Jun 9, 2012

Hubble Spots a Bright Spark in a Nearby Spiral Galaxy

A new image, taken by the NASA/ESA Hubble Space Telescope, shows a detailed view of the spiral arms on one side of the galaxy Messier 99. Messier 99 is a so-called grand design spiral, with long, large and clearly defined spiral arms -- giving it a structure somewhat similar to the Milky Way.

Lying around 50 million light-years away, Messier 99 is one of over a thousand galaxies that make up the Virgo Cluster, the closest cluster of galaxies to us. Messier 99 itself is relatively bright and large, meaning it was one of the first galaxies to be discovered, way back in the 18th century. This earned it a place in Charles Messier's famous catalog of astronomical objects.

In recent years, a number of unexplained phenomena in Messier 99 have been studied by astronomers. Among these is the nature of one of the brighter stars visible in this image. Cataloged as PTF 10fqs, and visible as a yellow-orange star in the top-left corner of this image, it was first spotted by the Palomar Transient Facility, which scans the skies for sudden changes in brightness (or transient phenomena, to use astronomers' jargon). These can be caused by different kinds of event, including variable stars and supernova explosions.

What is unusual about PTF 10fqs is that it has so far defied classification: it is brighter than a nova (a bright eruption on a star's surface), but fainter than a supernova (the explosion that marks the end of life for a large star). Scientists have offered a number of possible explanations, including the intriguing suggestion that it could have been caused by a giant planet plunging into its parent star.

This Hubble image was made in June 2010, during the period when the outburst was fading, so PTF 10fqs's location could be pinpointed with great precision. These measurements will allow other telescopes to home in on the star in future, even when the afterglow of the outburst has faded to nothing.

Read more at Science Daily

The Venus Transit and Hunting for Alien Worlds

Forget simply detecting a slight "dip" in brightness as an exoplanet transits in front of its star, soon we'll be able to image the event. What's more, by doing this we'll see that exoplanetary transits look exactly like the historic Venus transit that wowed the world on Tuesday.

This is according to astronomer Gerard van Belle, of Lowell Observatory near Flagstaff, Ariz., who hopes to use an interferometer to carry out the mind-blowing goal of capturing the silhouettes of exoplanets drifting in front of distant stars. But that's not all, this whole effort may help us track down the first bona fide Earth-like alien world.

"We're not just trying to take pictures of stars and see them as disks -- which is something we can do -- but the feather in our cap is to image one of these transit events and it would look just like the Venus event," van Belle told Discovery News. "This is something that's just coming to within our grasp."

NASA's Kepler space telescope looks for the tell-tail signs of exoplanetary transits by detecting the slight dimming of a star. This dimming is caused by an exoplanet passing between the star and Kepler -- the amount of dimming corresponds to the exoplanet's physical size and the length of dimming corresponds to its orbital characteristics. Although Kepler is sensitive to Earth-sized worlds, it isn't designed to directly image an exoplanet's silhouette (as shown in the artist's impression, top-right).

Interferometers, on the other hand, are a number of telescopes that are linked and their combined observational power can mimic a larger telescope with the equivalent diameter the distance that separates them. The Navy Optical Interferometer at Lowell Observatory or the CHARA (Center for High Angular Resolution Astronomy) array atop Mt. Wilson, Calif., are two interferometer systems that could achieve direct imaging of transits, says van Belle.

Also, in the aim of using the Venus transit to educate the world on what Kepler 'sees' when it detects exoplanet transits, the Venus transit turned out to be the ideal exoplanetary "analog." He added: "I think it's really timely that we should have this Venus event, so that if we get to the point of being able to accomplish (directly imaging an exoplanetary transit) in the next year, three years or so, people can say, 'oh yeah, that looks just like the Venus event except it's around another star!'"

But the connection between the Venus transit and exoplanet transits go far beyond just "looking the same"; valuable science was done during this week's Venus transit -- the last such event until the year 2117, in 105 years time.

As Venus drifted in front of the sun's disk, it blocked a tiny amount of sunlight. However, it also refracted a smaller amount of sunlight through its atmosphere.

Certain molecules in Venus' upper atmosphere would have absorbed certain wavelengths of light, so by using very sensitive spectrometers -- instruments that split light into its component wavelengths -- absorption lines that correspond to the presence of certain components of the Venusian atmosphere should have been detected.

"For Lowell Observatory, we have a spectrograph on one of our telescopes -- the 42 inch Hall Telescope -- that is designed to take light from a fiber and you can feed that into your instrument to do science. It splits the light up into its different colors," van Belle continued. "You can look for calcium lines and other sorts of elements in the spectra.

"With that fiber on the delivering end, you can either attach it to the back end of the telescope, where at night time it's used to look at the stars. But in the daytime you just run the fiber outside and point the end at the sun -- just the tip of the fiber has enough collecting area. We are the proud owners of the smallest optical telescope!"

Basically, the same spectrometer can be used to analyze the light from a very dim and distant star (with the Hall Telescope attached) or the light from our nearest star (without the telescope attached). Although the like-for-like comparison sounds like a great way to do science, van Belle cautioned that the spectra from refracted light through Venus' atmosphere may be too weak for the Lowell spectrometer to detect (although the data collected still needs extensive analysis).

But why go through the painstaking analysis of trying to analyze light refracted by Venus' atmosphere in the first place? We know the composition of the Venus atmosphere very well, why would we need to analyze it from from Earth?

We've landed robots on the hellish Venusian surface and the European Space Agency currently has a spacecraft in orbit around the planet -- Venus Express. We therefore have in-situ and orbital measurements of the planet's atmospheric composition. It is for this reason that observations of the Venus transit are so important.

If the analysis of the Venus transit's spectrum detects components of Venus' atmosphere, and they are in agreement with measurements made by Venus Express (for example), then we can learn a method of detecting the spectroscopic signature of exoplanetary atmospheres when we analyze starlight during exoplanetary transits. Venus, once again, is acting like a close-up exoplanet that we can study in the aim of honing our skills to detect the atmospheric composition of distant alien worlds.

"This is really the direction the whole game is going in with planets around other stars -- not just finding them; just a short while ago this was a big fat deal! Nowadays we're careening headlong into that being passé," said van Belle.

"Now the new name of the game is actually full-blown characterization of these planets; being able to establish how big they are, establish what their masses are, figure out what the atmospheres are made out of -- do they have a lot of water, carbon dioxide, or other more interesting things?

Read more at Discovery News

Jun 8, 2012

Parasitic Plants Steal Genes from Their Hosts

New research published June 8 in BioMed Central's open access journal BMC Genomics reveals that the Malaysian parasitic plant Rafflesia cantleyi, with its 50cm diameter flowers, has 'stolen' genes from its host Tetrastigma rafflesiae. Analysis of these genes shows that their functions range from respiration to metabolism, and that some of them have even replaced the parasites own gene activity.

Vertical gene transfer is that between parents and their offspring, while horizontal gene transfer is the movement of genes between two different organisms. Bacteria use horizontal gene transfer to exchange resistance to antibiotics. Recent studies have shown that plants can also use horizontal gene transfer, especially parasitic plants and their hosts due to their intimate physical connections.

Rafflesia cantleyi is an obligate holoparasite (dependent on its host, and only that host, for sustenance), which grows on Tetrastigma rafflesiae, a member of the grape family. Researchers from Singapore, Malaysia and USA collaborated to systematically investigate the possibility of horizontal gene transfer between these two plants. By looking at the transcriptome (the transcribed products of switched on genes) they found 49 genes transcribed by the parasite, accounting for 2% of their total transcriptome, which originally belonged to the host. Three quarters of these transcripts appear to have replaced the parasites own version.

Most of these genes had been integrated into the parasite's nucleus, allowing the researchers to perform genomic analysis. Over time DNA randomly mutates and investigation of genetic drift between the genes for these transcripts, between the parasite and host, showed that some time has passed since the genes were acquired and that they were acquired gradually.

Prof Charles Davis, from the Harvard University Herbaria, who co-led this project with Prof Joshua Rest from Stony Brook University, explained, "The elevated rate of horizontal gene transfer between T. rafflesiae and its parasite R. cantleyi raises the possibility that there is a 'fitness' benefit to the parasite. For example they may improve the parasites ability to extract nutrients from the host, or help it evade the host's defences, as has been seen for a bacterial pathogen of citrus trees."

Read more at Science Daily

It’s Official: Neutrinos Can’t Beat Speed of Light

Physicists at the CERN laboratory have put the final nail in the coffin for the idea that neutrinos can travel faster than the speed of light. They also confirmed that the groundbreaking results from 2011 can be blamed on faulty equipment.

Back in September 2011, a team of particle physicists detected neutrinos moving faster than the speed of light as they traveled from CERN to the Gran Sasso lab. They smashed the universal speed limit by 60 nanoseconds — a result that was constant, even after 15,000 repetitions of the process.

The results seem to run counter to a century’s worth of physics and would overturn Einsten’s special theory of relativity if true. As such, CERN called for more experiments to double-check the findings.

“When an experiment finds an apparently unbelievable result, it’s normal procedure to invite broader scrutiny,” CERN research director Sergio Bertolucci said at the time. “We need to be sure that there are no other, more mundane, explanations.”

At the International Conference on Neutrino Physics and Astrophysics in Kyoto on June 8, CERN research director Sergio Bertolucci presented results on the travel time of neutrinos from CERN to the INFN Gran Sasso Laboratory, on behalf of four experiments — Borexino, Icarus, LVD and Opera.

All four experiments measured a neutrino time of flight that was below the speed of light, confirming that neutrinos respect Einstein’s cosmic speed limit. The previous anomaly was “attributed to a faulty element of the experiment’s fibreoptic timing system.”

“Although this result isn’t as exciting as some would have liked,” said Bertolucci, “it is what we all expected deep down.”

“The story captured the public imagination, and has given people the opportunity to see the scientific method in action — an unexpected result was put up for scrutiny, thoroughly investigated and resolved in part thanks to collaboration between normally competing experiments.”

Read more at Wired Science

Stoneage Artists Created Prehistoric Movies

Stone Age artists used‭ ‬cartoon-like techniques to give the impression that wild beasts were trotting or running across cave walls,‭ ‬a new study‭ has suggested.

‭Reporting in ‬ the June issue of Antiquity, archaeologist Marc Azéma of the University of Toulouse–Le Mirail in France and independent French artist Florent Rivère, argued that by about‭ ‬30,000‭ ‬years ago Paleolithic artists used "animation effects" in their paintings. To render the movement, they deconstructed it in successive images.

According to the researchers, this would explain multiple heads or limbs on some cave paintings.

"Prehistoric man foreshadowed one of the fundamental characteristics of visual perception, retinal persistence," Azéma and Rivère wrote.

Azéma, who spent ‭ ‬20‭ ‬years researching Stone Age animation techniques,‭ isolated 53 ‬figures in‭ ‬12‭ ‬French caves which superimpose two or more images to represent trot or gallop,‭ ‬head tossing and tail shaking.‭

"Lascaux is the cave with the greatest number of cases of split-action movement by superimposition of successive images. Some 20 animals, principally horses, have the head, legs or tail multiplied," Azéma said.

When the paintings are viewed by flickering torchlight, the animated effect "achieves its full impact," said Azéma.

"That such animation was intentional is endorsed by the likely use of incised disks as thaumatropes," he added.

Regarded as the direct ancestor of the cinematic camera, the thaumatrope (literally "miracle wheel", from the Greek thauma, ‘prodigy’ and tropion, ‘turn’) was invented in 1825 by the astronomer John Hershel and later commercialized by the physicist John Ayrton Paris (1785– 1856).

Consisting of a card or disk with different designs on either side, the device demonstrates the persistence of vision: when the card or disk is twirled, the designs appear to blend into one.

Azéma's co-author, Florent Rivère discovered that Paleolithic artists used similar optical toys well in advance of their nineteenth-century descendants.

Rivère examined Magdalenian bone discs -- objects found in the Pyrenees, the north of Spain and the Dordogne which measure about 1.50 inches in diameter.

Often pierced in their centre, the discs have been generally interpreted as buttons or pendants.

"Given that some are decorated on both sides with animals shown in different positions, we realized that another type of use, relating to sequential animation, was possible," the researchers said.

Read more at Discovery News

Only Two Cosmic Doomsdays Are Certain

The sardonic proverb "nothing is certain but death and taxes," can now be recast for the cosmos.

Last week's announcement of the inevitable collision of the Andromeda galaxy with the Milky Way is one of only two apocalyptic astronomical predictions that we can be absolutely certain of. The other is the death of our sun. Purely deterministic processes drive both.

The eventual galaxy smashup is the result of the inexorable pull of gravity between two heavyweight "island universes" each weighing over 1 trillion times the mass of our sun.

300 years ago, Isaac Newton could have predicted this ultimate Clash of the Titans if he simply had mass and velocity data of the two galaxies. It's as inevitable as Newton's apple falling out of a tree.

The sun will burn out 6 billion years from now, leaving Earth a cold barren cinder. And, the sun's fate this can be extrapolated to every other star in the universe. The last one winks out 100 trillion years from now.

Beyond these two irrevocable events, all other cosmic disasters are simply probabilistic. You might want to take out homeowners insurance against them, but you can still hold out hope you'll never need to cash in on your policy.

The idea that the Milky Way's head-on collision won't happen for another 4 billion years from now, is wonderfully ironic considering some folks are still sweating over many silly end-of-world predictions linked to the Mayan Calendar "ending" in 2012. The broad spectrum of cosmic disasters bandied about on the Internet stretches from possible, to improbable, to utterly impossible.

Where to begin?

Statistically, a planet-killer class asteroid should whack us in less than 100 million years.

A nearby supernova could irradiate Earth within 250 million years.

Chaos theory allows for a small probability that the planets will become unstable in their orbits in a few billion years, and Earth may collide with Mars. But by then, Earth's oceans will have been evaporated away under the warming sun.

There is an infinitesimally small chance a bypassing star or rogue black hole will run into the sun. And those odd would slightly increase during the Milky Way-Andromeda collision event, although it is essentially a "collinsionless collision" -- there is a vast amount of interstellar space, so there will be few (if any) direct stellar smash-ups, although the gravitational instabilities will likely wreak dynamical chaos on galactic scales.

But wait a minute. The future technological prowess of our civilization should mitigate the worst effects of these disasters. Frankly, we deserve to become extinct if we don't have the wherewithal to come up with the money and technology to protect Earth from maundering asteroids. Call it the Cosmic Darwin Awards.

What's more, straightforward Newtonian physics could be applied to move Earth farther from the warming sun by setting up an interplanetary pinball game where we rob momentum from large asteroids and small planetary bodies to widen our orbit.

Read more at Discovery News

Jun 7, 2012

A Super Tiny Giraffe

Shaahin Amini was ready to quit. The Ph.D. student at the University of California, Riverside's Bourns College of Engineering had spent three hours looking into a microscope scanning a maze of black-and-white crosshatched lines, tubes and beads made of nickel, aluminum and carbon magnified 3,800 times.

Then he saw it. It looked like some kind of animal. He zoomed in further. It now looked like the road runner from the Bugs Bunny cartoons. He rotated it. Bingo! A sheep? No, a giraffe. A 0.05 millimeter giraffe.

He spent a few hours using Photoshop to add brown for the skin patches, red for the tongue and green in the background to resemble a jungle. It was done.

He submitted the piece to the Science as Art competition at 2012 MRS (Materials Research Society) Spring Meeting in San Francisco. Amini's piece, which was one of about 150 entries, was selected by the chairs of the meeting as one of the 50 finalists from throughout the world to be displayed in the exhibition hall.

"Exploration under the microscope will give you the chance to detach yourself from this world and momentarily live in a microscopic wonderland where beauty can be found in unexpected spots." Amini said. "At the meeting I saw attendees taking pictures of the giraffe and laughing at it. I was glad that people found it quite fascinating."

Amini is a fourth-year Ph.D. student working with Reza Abbaschian, dean of the Bourns College of Engineering and William R. Johnson, Jr. Family Professor of Engineering.

Amini's research area is the nucleation and growth kinetics of graphene layers from molten metals. Graphene is a single-atom thick carbon crystal with unique properties, including superior electrical and heat conductivities, mechanical strength and unique optical absorption, which could have widespread use in electronics. Amini, for the first time, developed a novel processing technique to grow single layer graphene from a molten phase.

Read more at Science Daily

Great Wall of China Twice As Long As Thought

The Great Wall of China is more than twice as long as originally believed, according to the first definitive archaeological survey of the iconic ancient defensive structure.

Released by the State Administration of Cultural Heritage (SACH), the survey began in 2007, mapping every trace of the wall across 15 Chinese provinces.

It emerged that the wall is much longer than previously thought. Indeed, it measures 13,170.6956 miles, or 21,196.18 km. A preliminary study released in 2009 estimated the wall to snake 5,500 miles, or 8,850 km across the country.

A total of 43,721 heritage sites were identified during the survey, "including stretches of the wall, defense works and passes, as well as other related Great Wall facilities and ruins," Tongo Mingkang, SACH deputy chief, said.

Known to the Chinese as the "Long Wall of 10,000 Li", the Great Wall is the world's largest human-made structure -- a series often overlapping fortifications made of stone, bricks and earthen works whose construction begun as early as the 7th century BC.

The defensive structure was first linked up under Emperor Qin Shi Huang in about 220BC. to protect the ancient Chinese empire from marauding tribes from the north.

Since then, many dynasties have maintained and renovated the wall. The majority of the existing structure was reconstructed during the Ming Dynasty (1368-1644).

Today, only 8.2 percent of the wall built during the Ming Dynasty is intact, with the rest in poor condition, said the report.

Listed as a Unesco world heritage site in 1987, the wall has been heavily damaged from human activities, infrastructure development and tourism.

A large amount of the wall has collapsed and in some sections, only its foundation remains, the five-year survey concluded.

Read more at Discovery News

Secrets of Hard-Hitting Crustacean Claw Found

If sea creatures were Marvel comic book characters, the peacock mantis shrimp would be Thor. These colorful crustaceans have a hammerlike claw that can smash prey with the acceleration of a 0.22-caliber bullet — not unlike the superhero's mythological weapon.

Now, a new study reveals the secrets behind the strength of the mantis shrimp's claw at the molecular level. It turns out this appendage is ideally adapted to deliver punishing blow after punishing blow without breaking. These adaptations are already inspiring researchers to engineer biology-mimicking materials that could inspire everything from better boat propellers to safer body armor.

"What makes [mantis shrimp claws] so incredible is that they're stiff and they're also tough, which is really kind of an inverse relationship in materials science," said study researcher David Kisailus, a materials scientist at the University of California, Riverside.

Dangerous claw

Using electron microscopes and other sensitive techniques, Kisailus and his colleagues delved deep into the claw of the Indo-Pacific peacock mantis shrimp (Odontodactylus scyllarus). These crustaceans aren't actually shrimp, but they get their name from their shrimplike appearance, which Kisailus and his colleagues compare to "heavily armored caterpillars" in this week's issue of the journal Science.

Peacock mantis shrimp are solitary, territorial hunters. They lurk in dens or seafloor tunnels and use their hammerlike claws to kill mollusks, crabs and other tasty treats.

Fishermen sometimes call mantis shrimp "thumb-splitters," for reasons that aren't hard to imagine, given that the shrimp can wield their claws at speeds of 75 feet (23 meters) per second and deliver blows with 200 pounds (91 kg) of force behind them despite being only 4 inches (10 cm) long. These blows also create bubbles in the water that strike prey with about half the force of the initial strike. [Video: See Mantis Shrimp Strike]

Kisailus has experienced these forces firsthand, thanks to the mantis shrimp he keeps in his lab. Curiosity has gotten the best of him and his colleagues, Kisailus told LiveScience, and they have, on occasion, stuck their fingers in the mantis shrimp tanks — with multiple layers of rubber gloves and wax film for protection.

"It still hurts like hell," Kisailus said. "It didn't break our fingers after putting so many layers on, but I'm sure if we didn't, it would have."

Secrets of strength

Mantis shrimp molt and replace their claws every few months, but they still strike tens of thousands of times with each iteration of these clublike appendages. Kisailus and his colleagues found that this incredible strength comes from three different regions in the claw. The impact region, or striking surface, is dominated by a mineral called hydroxyapatite, a calcium-containing substance that gives human bones their hardness. The mineral is arranged so that it forms pillars perpendicular to the striking surface, not unlike a concrete pylon holding up a bridge.

A second region called the periodic region backs up the impact zone with chitosan, a carbohydrate molecule that forms long chains and makes up part of chitin, the substance in crustacean shells.

The chitosan in a peacock mantis' claw, which lies just beneath the impact zone, is stacked at different orientations, like a ream of paper where every sheet has been angled slightly askew. That makes it tough to crack, as any crack that does form has to change directions in order to continue through the claw.

Read more at Discovery News

How Vampire Spiders Choose a Blood Meal

Jumping spiders, also known as vampire spiders, have a very specific diet: female mosquitoes that have just fed on blood. A new study using "Franken-mosquitoes"— glued-together parts of different mosquitoes — finds that the spiders check for not only a blood-red belly but also for girly antennae while choosing where to pounce.

"In the past it was thought that jumping spiders responded to very basic stimuli that triggered predatory behavior. Something along the lines of, 'It is small and it moves, therefore it is prey,'" study researcher Ximena Nelson, of the University of Canterbury, in New Zealand, told LiveScience.

The new study indicates they are much pickier eaters than that, Nelson said: "It is clear from these results that this type of 'algorithm' is not used by E. culicivora [the jumping spider]. At the very least, it is much more sophisticated."

Picky eater

The spider's favorite food by far is freshly blood-filled mosquitoes, and this arachnid species seems to need the blood to survive, the researchers said, hence the "vampire" moniker.

"Other 'bugs' in general are not as tempting, possibly because of the absence of vertebrate blood," Nelson said. This blood "does seem to be integral to the diet of this spider, although we are not entirely sure why this is."

On the shores of Lake Victoria in Sub-Saharan Africa, the spiders stalk sitting mosquitoes until they are about an inch (2 to 3 centimeters) away, then jump on them. The youngest of the spiders actually jump onto the stomachs of mosquitoes and bite them in midflight. They hold on as the insects drop to the ground, then devour them.

Finding females

Since the spiders need the blood the female mosquitoes have ingested, it's important for them to choose the right prey. Female mosquitoes look slightly different from the males.

"A trained human with decent eyesight can detect the difference without much difficulty, but it is solely on the basis of how 'fluffy' the antennae look," Nelson said. "Males have more 'setae' on their antennae," which make their headgear fuzzier than the females'.

The spiders are also on the lookout for the swollen red belly of a recently blood-fed female.

To find out what features the spiders use to choose their target, the researchers created "Franken-mosquitoes" by gluing together body parts of starved and blood-fed male and female mosquitoes (the head and thorax of one, the abdomen of another).

Read more at Discovery News

Jun 6, 2012

New Clues About the Origin of Cancer

A study by Travis H. Stracker, researcher at the Institute for Research in Biomedicine (IRB Barcelona), in collaboration with scientists at the Memorial Sloan Kettering Cancer Center (MSKCC) in New York, reveals new information about the origin of tumors. In this study, published in the journal Proceedings of the National Academy of Sciences (PNAS), the scientists postulate that the initiation of a tumor and the type and aggressivity of the same depend on a specific combination of defects in several processes that safeguard cell integrity, such as DNA repair pathways and cell cycle check-points. The study also demonstrates that mice with a high degree of chromosomal instability and defective programmed cell death (apoptosis), two hallmarks of cancer, rarely develop tumors.

"Whether or not a tumor develops depends on the moment of the cell cycle in which the damage occurs, which repair pathways components are affected, and which others are impaired in terms of apoptosis and cell cycle arrest," explains the North-American Travis H. Stracker, head of the "Genomic Instability and Cancer" group and an expert in DNA repair pathways and its implications on human health. In this study, H. Stracker and his team report on some of these combinations for the initiation of cancer and in different kinds of tissue. "The paper points out that our understanding of which aspects of damage response promote tumorigenesis and where they play a role in the process needs to be investigated further because it shows that it has been generalized and that there is a lot of specifics that are not at all clear."

The researchers utilized mice carrying mutations in key DNA repair genes involved in cancer. Next, they combined them with other mutations affecting cell cycle checkpoints or apoptosis until they hit upon the combinations that are sufficient to initiate tumorigenesis or to generate certain types of tumors. "It is like deconstructing cancer to find the factors responsible for it appearing," says H. Stracker. During DNA replication in a dividing cell there is a series of checkpoints to test that duplication is taking place properly. If the cell detects errors in any of these phases, cell growth is halted and highly complex DNA repair processes are triggered. If the repair is defective and the cell accumulates many genomic errors, "watch-out" proteins step in, such as tumor suppressor p53. Such proteins activate programmed cell death (apoptosis) or cell cycle arrest (senescence). "A very complex network of pathways and proteins are involved," explains the researcher.

Read more at Science Daily

Evolution Under Assault in South Korea’s Schools

Publishers in South Korea are set to remove examples of evolution from school textbooks following a petition driven by independent body the Society for Textbook Revise, according to a report in Nature.

The body, which is an offshoot of the Korea Association for Creation Research, won its campaign to remove mentions of the evolution of the horse and of the Archeopteryx — an avian ancestor from the late Jurassic period — from secondary school textbooks last month, using conflicting debates in evolutionary research on the Archeopteryx capacity to fly as support for its position. Its sights are now set on removing excerpts on human evolution and references to Darwin’s infamous finch research from On the Origin of Species.

Researchers in the field claim they were not consulted and that the petition instead went directly to the publishers who made the decision.

The news comes days after a poll by news site Gallup revealed that 46 percent of Americans believe in the creationist theory that God created man in the last 10,000 years. A third believe humans evolved under God’s guidance. When Gallup conducted the same poll in the US 30 years ago, the results were the same, give or take a few percent, demonstrating that despite countless research studies confirming otherwise, little has changed among the country’s conservative right.

In South Korea 26 percent of the population belong to a Christian denomination and over 23 percent are Buddhists, however the latter do not recognise any god or creator, so for many evolution does not conflict with the religion. This is compared to the US, where nearly 80 percent of the population is Christian.

Creationism in South Korea gained more attention following the 1980 World Evangelisation Crusade, which was held in Seoul. The following year, the Korea Association for Creation Research was setup. The association’s website stays up to date with current evolutionary research, publishing news stories that often state the facts as published, before going on to poke holes in the results, point out that “accidents” of “random mutations” were surely by design, before finishing off with a few references to “the Creator”.

The country’s anti-evolutionary sentiment appears to already be widespread within the schooling system, with a recent survey of trainee teachers in the country revealing half of those questioned disagreed with the statement that “modern humans are the product of evolutionary processes”.

Read more at Wired Science

'Vampire' Skeletons Found in Bulgaria

Two medieval "vampire" skeletons emerged near a monastery in the Bulgarian Black Sea town of Sozopol, local archaeologists announced.

Dating back 800 years to the Middle Ages, the skeletons were unearthed with iron rods pierced through their chests -- evidence of an exorcism against a vampire. The ritual was aimed at preventing potentially dangerous people, such as enemies, murderers or individuals who died suddenly from a strange illness, from turning into vampires after death.

"The practice was common in some Bulgarian villages up until the first decade of the 20th century," Bozhidar Dimitrov, chief of the National History Museum in Sofia, told reporters.

The newly discovered skeletons are the latest in a series of finds across Europe. According to Dimitrov, over 100 skeletons, buried in the same manner, had been unearthed in Bulgaria only.

Vampires of the time were quite different from the aristocratic blood-sucking character depicted in Bram Stoker's 1897 Gothic horror novel "Dracula" and in innumerable Hollywood movies.

Indeed, the vampire legend originated from the disturbing appearance of decomposing bodies that had succumbed to the plagues that ravaged Europe between 1300 and 1700.

During those epidemics, mass graves were often reopened to bury fresh corpses and gravediggers would stumble into bodies that were bloated by gas.

Featuring a hole in the shroud used to cover their faces, these bodies showed individuals with their hair still growing, their teeth appearing through the shroud, and blood seeping out of their mouths.

In a time before germ theory, when the decomposition of corpses was not well understood, these individuals appeared like they were still alive, drinking blood and eating their shrouds.

Modern forensic science would explain that the shrouds were consumed by bacteria found in the mouth area, but at that time it was believed that these "shroud-eaters" were vampires who spread pestilence.

Read more at Discovery News

Dinosaurs Skinnier Than Previously Thought

Dinosaurs were often hefty, but not as plump as previously thought.

A new study describes a new technique used to measure the weight and size of dinosaurs and other prehistoric animals. It could forever change museum exhibits, book illustrations, and other recreations of these now-extinct species. The study appears in the latest issue of Biology Letters

“This is a huge help for any sort of reconstruction,” lead author William Sellers told Discovery News. “We now have a number that suggests how much flesh to add to the bones and that should help people produce animals that are the right balance of too fat or too thin.”

“This technique can also allow you to calculate the numbers you need for more sophisticated locomotor reconstructions, such as the running simulations we have produced in the past,” added Sellers, who is based at the University of Manchester’s Faculty of Life Sciences.

He and his team used lasers to measure the minimum amount of skin required to wrap around the skeletons of large modern animals that included reindeer, polar bears, giraffes and elephants. Doing this, the researchers noticed that the animals had almost exactly 21 percent more body mass than the minimum skeletal “skin and bone” wrap volume.

The formula was then applied to a giant Brachiosaur skeleton housed at Berlin’s Museum für Naturkunde. Previous estimates of this dinosaur’s weight have been as high as 176,370 pounds. This latest study, however, reduces the figure to just 50,706 pounds -- impressively weighty, but not nearly as heavy.

“The 23 tonne weight (50,706 pounds) is quite low, but I think it reflects the fact that all dinosaur weights are getting lower,” Sellers said, explaining that the estimated weight for this dino, along with other species, has been dropping since about the early 1960’s.

He continued that the new estimate "reflects a better understanding of biology, and I think the early estimates were set in that big, fat and slow lizard mindset before the dinosaur renaissance. I think we will find that the lower estimates are much more appropriate for many dinosaurs.”

High-tech scanners, fast computers and other tools were simply not available back in the day when dinosaur weights were first estimated. Up until fairly recently, even experts resorted to some fairly homespun methods for attempting to calculate dinosaur heft.

“One very common method is to take an artist’s reconstruction sculpture of the animal and measure its volume by dipping it in water just like Archimedes," Sellers said. "That gives you the volumes, which you can multiply by the density to get its weight.”

Read more at Discovery News

Jun 5, 2012

Exceptional Rise in Ancient Sea Levels Revealed

Since the end of the last ice age 21,000 years ago, our planet has seen ocean levels rise by 120 meters to reach their current levels. This increase has not been constant, rather punctuated by rapid accelerations, linked to massive outburst floods from the ice caps. The largest increase, known by paleoclimatologists as 'Melt-Water Pulse 1A', proved to be enigmatic in many respects. A study recently published in Nature by a team from the CEREGE laboratory in collaboration with the universities of Tokyo and Oxford has revealed the mysteries of this event, without doubt one of the most important in the last deglaciation.

A spectacular rise

The research has primarily confirmed the existence of this exceptional event, which had been controversial in some regards. Its chronology, amplitude and duration have now been defined. It began precisely 14,650 years ago and coincides with the start of the warm period known as the 'Bølling oscillation', which marked the end of the ice age. The rise in sea levels at that time was an average of 14m worldwide, over less than 350 years. This corresponds to a rate of 40mm per year -- compared to the 3mm per year we are currently experiencing.

Coral: a climate archive

To describe this remarkable event, researchers analysed cores taken from the coral reef surrounding Tahiti, Polynesia, during the international IODP 310 'Tahiti Sea Level'(4) expedition. The corals that built these reefs and atolls are excellent indicators of sea level variation* and also provide a virtual archive of previous climates(5).

Using reconstructions of sea levels from the fossilised corals as well as geophysical simulations, scientists have been able to identify the source of this accelerated rise in sea levels. They have demonstrated that the Antarctic ice cap was responsible for up to 50% of these increases. Experts had previously believed that only melting ice from the Northern hemisphere had contributed to Melt-Water Pulse 1A, particularly the Laurentide ice cap that covered a large part of North America.

To demonstrate the mechanisms occurring, the research team compared the rise in water levels in Polynesia with those observed during a previous research expedition to Barbados, in the Caribbean. According to the previously accepted hypothesis, the amplitude of the increase in sea levels must have been twice as large in Tahiti than in Barbados, which was closer to the Laurentide ice cap. And yet, the study showed that the rise was equivalent in these two locations, implying a highly significant role played by the Antarctic ice cap.

A modified global climate

These studies have shed new light on the complex relationship between climate, ocean circulation and sea levels. By demonstrating the synchronicity between Melt Water Pulse 1A and the warming of the Bølling oscillation, they have specifically demonstrated the part played by the massive oceanic inflow of fresh water in planetary deglaciation. This almost certainly caused major disturbances to thermohaline circulation(6) in the global ocean, which itself had a discernable impact on the global climate. This study also demonstrates the complex reaction of the ice caps to a major climactic disturbance, particularly for the potential instability of the Antarctic ice cap.

From past to present…

These results are highly important with regard to the current rise in sea levels, which is one of the most worrying effects of global warming dating from the start of the industrial era. In the past century, marigraphic data have suggested that ocean levels have risen by between 1.5 and 2mm per year. More recently, altimetry satellites have demonstrate an average global rise of 3.3mm per year over the past two decades. Although the estimates of their respective contributions are still being studied, it is clear that the thermal expansion of the oceans, in addition to melting polar ice caps and mountain glaciers, are the major causes.

Read more at Science Daily

How Infectious Disease May Have Shaped Human Origins

Roughly 100,000 years ago, human evolution reached a mysterious bottleneck: Our ancestors had been reduced to perhaps five to ten thousand individuals living in Africa. In time, "behaviorally modern" humans would emerge from this population, expanding dramatically in both number and range, and replacing all other co-existing evolutionary cousins, such as the Neanderthals.

The cause of the bottleneck remains unsolved, with proposed answers ranging from gene mutations to cultural developments like language to climate-altering events, among them a massive volcanic eruption.

Add another possible factor: infectious disease.

In a paper published in the June 4, 2012 online Early Edition of The Proceedings of the National Academy of Sciences, an international team of researchers, led by scientists at the University of California, San Diego School of Medicine, suggest that inactivation of two specific genes related to the immune system may have conferred selected ancestors of modern humans with improved protection from some pathogenic bacterial strains, such as Escherichia coli K1 and Group B Streptococci, the leading causes of sepsis and meningitis in human fetuses, newborns and infants.

"In a small, restricted population, a single mutation can have a big effect, a rare allele can get to high frequency," said senior author Ajit Varki, MD, professor of medicine and cellular and molecular medicine and co-director of the Center for Academic Research and Training in Anthropogeny at UC San Diego. "We've found two genes that are non-functional in humans, but not in related primates, which could have been targets for bacterial pathogens particularly lethal to newborns and infants. Killing the very young can have a major impact upon reproductive fitness. Species survival can then depend upon either resisting the pathogen or on eliminating the target proteins it uses to gain the upper hand."

In this case, Varki, who is also director of the UC San Diego Glycobiology Research and Training Center, and colleagues in the United States, Japan and Italy, propose that the latter occurred. Specifically, they point to inactivation of two sialic acid-recognized signaling receptors (siglecs) that modulate immune responses and are part of a larger family of genes believed to have been very active in human evolution.

Working with Victor Nizet, MD, professor of pediatrics and pharmacy, Varki's group had previously shown that some pathogens can exploit siglecs to alter the host immune responses in favor of the microbe. In the latest study, the scientists found that the gene for Siglec-13 was no longer part of the modern human genome, though it remains intact and functional in chimpanzees, our closest evolutionary cousins. The other siglec gene -- for Siglec-17 -- was still expressed in humans, but it had been slightly tweaked to make a short, inactive protein of no use to invasive pathogens.

"Genome sequencing can provide powerful insights into how organisms evolve, including humans," said co-author Eric D. Green, MD, PhD, director of the National Human Genome Research Institute at the National Institutes of Health.

In a novel experiment, the scientists "resurrected" these "molecular fossils" and found that the proteins were recognized by current pathogenic strains of E. coli and Group B Streptococci. "The modern bugs can still bind and could potentially have altered immune reactions," Varki said.

Though it is impossible to discern exactly what happened during evolution, the investigators studied molecular signatures surrounding these genes to hypothesize that predecessors of modern humans grappled with a massive pathogenic menace between 100,000 and 200,000 years ago. This presumed "selective sweep" would have devastated their numbers. Only individuals with certain gene mutations survived -- the tiny, emergent population of anatomically modern humans that would result in everyone alive today possessing a non-functional Siglec-17 gene and a missing Siglec-13 gene.

Varki said it's probable that humanity's evolutionary bottleneck was the complex result of multiple, interacting factors. "Speciation (the process of evolving new species from existing ones) is driven by many things," he said. "We think infectious agents are one of them."

Read more at Science Daily

Why Humans Prevailed Over Neanderthals

One hundred thousand years ago, several humanlike species walked the Earth. There were tribes of stocky Neanderthals eking out an existence in Europe and northwest Asia, and bands of cave-dwelling Denisovans in Asia. A diminutive, hobbitlike people called Homo floresiensis inhabited Indonesia. What were essentially modern humans roamed Africa.

Then, about 60,000 years ago, a few thousand of those humans migrated out of Africa. As they slowly moved into new territories over the course of generations, they encountered the Neanderthals, the Denisovans and the hobbit people — all of whom descended from hominin groups that had left Africa during prior waves of migration. DNA analysis shows the humans interbred with these strangers, but other details of the encounters are lost to history. One thing is clear: only humans remain.

Why did we prevail? A panel of experts discussed their latest interpretations of genetic and fossil evidence Saturday (June 2), at the fifth annual World Science Festival in New York. Humanity's success, they said, appears to be a "revenge of the nerds" story of global proportions.

First, although Neanderthals had as big a brain as anyone, the shapes of their fossilized skulls indicate humans had slightly larger frontal lobes, said Chris Stringer, a paleoanthropologist at the Natural History Museum in London. That brain region controls decision-making, social behavior, and such uniquely human tendencies as creativity and abstract thought. Meanwhile, Neanderthals were broader and stronger than us, with especially powerful upper bodies, and their robustness made them better adapted to Europe's cold climate. "In a sense, we're wimps," Stringer said. "Physically, we didn't have any advantage over the Neanderthals — quite the opposite."

This would suggest brains won out over brawn, and that rather than destroying our enemies in some epic battle, our ancestors may simply have been savvier survivors, steadily growing our numbers while our burlier brethren met their demise.

Braininess helped us broaden our diets, for example. We had smaller teeth than Neanderthals, suggesting we put some of those superior abstract thinking skills toward processing food (such as pounding cooked yams), which would have conferred a major survival advantage. "The more processing you do before it goes in your mouth, the more energy you save," Stringer said. "If you want your kids to survive, you can process the food for them as well."

Ancient hunting tools such as snares and fishing nets suggest we may also have been more efficient hunter-gatherers. "Modern humans had technology that allowed them to get a more consistent, reliable and balanced diet," said Alison Brooks, an anthropologist at George Washington University.

Another handy cognitive capacity allowed the rapid spread of new technologies, as well as the sharing of knowledge and information relevant for survival: We were — and clearly still are — adept social networkers. According to Brooks, excavations of ancient human settlements in Africa have turned up stashes of stone tools located as many as 100 kilometers from where the stones were quarried, implying the presence of a sophisticated and multidirectional trade network. "You're seeing a completely different approach to social organization in modern humans … than we're seeing in the Neanderthals," Brooks said. "Neanderthals simply did not do this."

Why didn't they? Such activities would have required the ability to communicate in great detail, which raises an important question in terms of the other hominins' demise: Were Neanderthals, Denisovans and Homo floresiensis capable of language, and if so, how well-developed was their system of communication? "If they could talk, then perhaps that's not the reason why we beat them, but if they couldn't, it's an obvious reason," said Ed Green, a genome biologist at the University of California, Santa Cruz, and a member of the team that sequenced the Neanderthal genome in 2010 using DNA from fossils. "If you think about all the things that you know, and calculate how much of that you figured out yourself versus what was told to you, it's obvious how important speech and language is and being able to communicate."

Neanderthals probably did have some form of language. They appear to have had a gene that is crucial to language in humans, and they buried their dead, which seems too complex an idea to have arisen among a tribe of mutes. But Brooks argues they may have lacked the vocal cords necessary for complex communication. "The sounds they made would have been a little bit less distinct" — somewhat like the speech of a 2-year-old, she said. That would imply they communicated in small groups, but not with others in a network; they simply wouldn't have been able to make sense of individuals with different accents.

Read more at Discovery News

Did Early Birds Exterminate Giant Insects?

Giant insects that ruled prehistoric skies for millions of years may have met their end due to the evolution of predatory birds, researchers say.

Gigantic insects once dominated the Earth. About 300 million years ago, during the late Carboniferous and early Permian periods, the largest flying insects  known, the predatory dragonfly-like griffinflies, had wingspans of up to 28 inches, about the same as the modern wood duck.

The leading theory of how flying insects reached such stupendous sizes has to do with past periods of high oxygen concentrations in the atmosphere, reaching up to some 50 percent richer than today. All this extra oxygen is thought to have supported the energy-hungry metabolisms of flying insects, helping them grow to titanic maximum sizes.

To test this theory linking oxygen with body size, paleontologists Matthew Clapham and Jered Kerr at the University of California, Santa Cruz, compiled a data set of insect wing lengths from more than 10,500 fossils collected from more than 1,000 published records. They next compared wing sizes with models of prehistoric atmospheric oxygen levels from data spanning the last 320 million years.

The researchers found that average insect wing size roughly matched atmospheric oxygen levels as they varied up and down for the first 150 million years of insect evolution.

Clapham and Kerr detailed their findings online June 4 in the Proceedings of the National Academy of Sciences.

"Before, we only had anecdotal reports that there were giant insect fossils in the late Carboniferous and early Permian when oxygen levels were high, but no one had looked systematically at the maximal size of insects over a broad range of evolutionary time," said evolutionary physiologist Jon Harrison at Arizona State University, who did not take part in this research.

However, Clapham and Kerr found this pattern changed dramatically about 150 million years ago, with insect size shrinking despite rising oxygen levels. They  note this shift coincided with the first appearance of birds in the fossil record. They suggest that given the aerial threat posed by feathered predators, the driving force in the evolution of flying insects became the need for maneuverability, thus favoring smaller body size.

In addition, maximum insect size decreased further between 60 million and 90 million years ago. This change might be linked with how ancient birds got better at flying during this period, as they came to resemble modern birds in performance by then, Clapham said. Another factor could be the evolution of bats, or environmental collapses following the so-called K-T mass extinction that ended the age of dinosaurs about 65 million years ago. More insect fossils from this time are needed to judge which factors might be responsible.

Ancient insects contended with other aerial predators, including the flying reptiles known as pterosaurs, which appeared about 230 million years ago and perished with the K-T mass extinction. The researchers found weak evidence that insect size shrunk after pterosaurs evolved, although a 20-million-year gap in the insect fossil record and a drop in oxygen level at about the same time has made it challenging to see how much of an effect pterosaurs had.

"Although there is evidence from pterosaur teeth that some may have been insectivorous, I think they probably weren't as agile or maneuverable fliers as birds so it would make sense that they had a lesser effect on size evolution," Clapham said.

Although these findings suggested the maximum sizes that insects reached were influenced by atmospheric oxygen, future research can seek to see if average insect sizes also rose and fell with oxygen levels.

"Our results describe changes in the maximum size of the largest insects, not changes in the size of all insects," Clapham said. "Even though there were giant insects in the past, most insects have always been small like they are today."

The problem with studying if atmospheric oxygen levels influenced average insect wing size is that the wings of small insects may not always get preserved very well -- they may be too small to make enough of an impression on surrounding sediment that survives to get fossilized.

Read more at Discovery News

Jun 4, 2012

Groundbreaking X-Ray Snapshots of Active Photosynthesis

Working with researchers in the US and Germany, Johannes Messinger at Umeå University is opening new avenues to understand photosynthesis and create artificial photosynthesis. Using x-ray analysis, they have managed to see the structure of molecules under conditions where photosynthesis can occur, and they have also found that calcium plays a critical role in decomposing water.

The solar energy reaching Earth is 5,000 times greater than all energy consumption in the world. To be able to exploit this source of energy and store it would help solve humans' more and more acute energy problems.

Two major research projects at Umeå University are devoted to developing artificial photosynthesis by imitating plants' extremely successful way of making use of energy from the sun. Both projects ("solar fuels" and "artificial leaf") are directed by Johannes Messinger, a professor at the Department of Chemistry, Umeå University.

To be able to create an "artificial leaf," researchers need to study the ingenious system that plants have used for millions of years on earth. We need to answer two crucial questions: What molecules are necessary to break down water in plant photosynthesis? What is their role, that is, how do they function and when?

In collaboration with American and German colleagues (there are a total of 36 authors of the publication), Johannes Messinger has devised a tool to investigate plant photosynthesis systems while they are active. Using ultra-short x-ray flashes, they have succeeded in performing structural analyses of isolated photosynthesis molecules from plant photosystem II at room temperature. The movement of the atoms was registered for a period of 50 femtoseconds (10-15 seconds). The equipment used, an x-ray free-electron laser, is located at Stanford University in the US.

Normally the structure of molecules is determined by using x-ray flashes in frozen samples. But because the x-ray flashes used in this experiment are so brief, they do not last long enough to disrupt the photosystem during measurement. This opens new possibilities of discovering structures and studying how the system reacts in the leaf under natural conditions when they are actively carrying out photosynthesis.

"Our objective is to study how oxygen atoms form a bridge to create oxygen molecules when water is broken down. Until now, it has been impossible to study this phase of photosynthesis in detail," says Johannes Messinger.

In his efforts to construct an artificial leaf that can convert water to hydrogen and oxygen, the Umeå scientist, together with collaborative partners at the Max Planck Institute for Bioinorganic Chemistry, have discovered another building block. It is already known that calcium ions are involved in decomposing water and that a system that has no calcium cannot produce oxygen. But the researchers now wanted to find out whether calcium is necessary to keep the structure of the photosystem stable (especially manganese ions) or whether calcium is needed in the reaction itself.

The research team managed to remove the calcium ions from the whole molecule complex and then study the structure using EPR spectroscopy, electron paramagnetic resonance.

Read more at Science Daily

Wallflowers of the Earth System

In cities, the presence of algae, lichens, and mosses is not considered desirable and they are often removed from roofs and walls. It is, however, totally unfair to consider these cryptogamic covers, as the flat growths are referred to in scientific terms, just a nuisance. Scientists at the Max Planck Institute for Chemistry have discovered that these mostly inconspicuous looking growths take up huge amounts of atmospheric carbon dioxide and nitrogen and fix it at Earth's surface.

Cryptogamic covers are responsible for about half of the naturally occurring nitrogen fixation on land and they take up as much carbon dioxide as is released yearly from biomass burning. These new findings will help to improve global flux calculations and climate models, in which up to now the carbon and nitrogen balance of the cryptogamic covers have been neglected.

The roles that forests and oceans play in the climate and in the global exchange of oxygen, carbon, and nitrogen have been documented in numerous scientific studies. The importance of algae that grow on land, lichens, and mosses for the nitrogen and carbon fluxes and also for the carbon dioxide balance is normally not taken into consideration. This even though cryptogamic covers including the blue green algae (cyanobacteria) cover approximately 30% of soil surface that includes the surfaces of plants. Life forms that get their energy through photosynthesis, but don't flower, belong to the cryptogams. They are found in all ecosystems, not just on roofs, trees, or walls. Cryptogamic covers, which consist of some of the oldest life forms on our Planet, are also found on cliffs and in soils in dry regions.

"Actually, we wanted to know which compounds the cryptogamic covers emit into the air," said Wolfgang Elbert, who initiated the research at the Max Planck Institute of Chemistry. "We found that there are a lot of studies about the ecological role of these life forms, but their contribution to the global nitrogen and carbon balance has been neglected until now." To get at the importance of the cryptogamic covers, the chemists analysed the data from hundreds of studies in cooperation with biologists and geologists. Their finding: Algae, mosses, and lichens take up approximately 14 billion tons of carbon dioxide and fix approximately 50 million tons of nitrogen per year.

The magnitude of these numbers surprised the Mainz researchers and their colleagues at the University of Kaiserslautern and the Biodiversity and Climate Research Centre in Frankfurt because the cryptogamic covers take up about as much carbon dioxide as is annually released by the burning of forests and other biomass.

Especially amazing is the amount of nitrogen that is fixed by the cryptogams and that is thereby made available in the soil and to other organisms. "This represents half of the naturally fixed nitrogen on land, which is of particular importance for ecosystems because nitrogen is often the limiting nutrient. Also, the uptake of CO2 by plants is often limited by the availability of nitrogen," explained Ulrich Pöschl, leader of the research group.

Read more at Science Daily

Earliest Known Human Relatives Came from Asia

The ancestors of humans, apes and monkeys evolved first in Asia before moving on to Africa, suggests a new fossil find from Myanmar.

Remains of a newly found primate, Afrasia djijidae, show this monkey-like animal lived 37 million years ago and was a likely ancestor of anthropoids -- the group including humans, apes and monkeys.

"Many people have heard about the 'Out of Africa' story of human origins and human evolution," said Christopher Beard, a Carnegie Museum of Natural History vertebrate paleontologist who co-authored a study about the fossil find in the latest Proceedings of the National Academy of Sciences. "Our paper is the logical precursor to that, because we are showing how the anthropoid ancestors of humans made their way 'Into Africa' in the first place."

He added, "We would not be here talking about this subject, or any other subject, if these early Asian anthropoids had not made that fateful voyage to Africa."

Beard, project leader Jean-Jacques Jaeger of the University of Poitiers, and their colleagues analyzed the tooth remains of Afrasia. They found that it is very similar to, but more primitive than, another early anthropoid, Afrotarsius libycus, recently discovered at a site of similar age in the Sahara Desert of Libya. (The term "anthropoid" is used instead of "primate" because all anthropoids are primates, but not all primates are anthropoids. Lemurs, for example, fall into that latter group.)

The tooth size of Afrasia and Afrotarsius indicates that in life, both animals only weighed around 3.5 ounces. They likely fed mostly on insects and probably resembled small monkeys, Beard said.

Although quite similar, the fossils differ in that Afrasia is more closely tied to the world’s oldest known anthropoid, Eosimias, which lived between 40-45 million years ago in China.

It remains a mystery as to how the small Asian animals came to Africa.

"What we do know is that they had to cross a much larger version of the Mediterranean Sea (the ancient body of water was called the Tethys Sea) in order to go from Asia to Africa," Beard said. "At that time, Africa was an island continent like Australia is today."

He said one possibility is that the early Asian anthropoids rafted across the Tethys on a floating island of tree-covered land that may have eroded off large riverbanks in Asia during storms and floods. Beard explained, "There have been a few examples where scientists have found animals living on mats of vegetation like this, out at sea, following a hurricane or large storm."

Afrasia, he said, "is a close relative of humans and other living anthropoids. It is a member of an evolutionary side-branch of the monkey, ape and human family tree."

He and his colleagues suspect that this branch eventually went extinct. It is likely that multiple Asian anthropoid species were able to colonize Africa 38-37 million years ago, with one species evolving many years later into Homo sapiens.

So far, it appears that the close ancestors of Afrasia, which remained in Asia, also went extinct. Some anthropoids made the journey back to Asia from Africa, however. Orangutans, for example, made that trip about 10 to 15 million years ago.

"Human ancestors left Africa much more recently than that," Beard said, explaining that the oldest fossil human relatives outside of Africa are about 1.8 million years old. "They come from the former Soviet Republic of Georgia."

Read more at Discovery News

Taking Venus' Temperature During Transit

As excitement builds for Tuesday's Venus transit, astronomers hope to catch a rare and exciting glimpse of the planet's atmosphere. What's more, by analyzing the sunlight refracted through the Venusian upper atmosphere, we may also gauge its temperature.

During historic Venus transits, the celestial event has been used by astronomers as a scientific tool to precisely measure the distance from Venus to Earth, and Earth to the sun. In this modern age, these distances are well known -- we also have robotic spacecraft orbiting all the inner planets, Mercury, Venus and Mars taking in-situ observations -- but remote observations from Earth are a great means of validating these measurements.

Although Venus currently has a spacecraft in orbit -- the European Space Agency's Venus Express -- some rather exciting observations of the Venusian atmosphere will also be made.

Just as the transit begins at 3:09 p.m. PDT (6:09 p.m. EDT) on June 5 (Tuesday), astronomers will be looking for a phenomenon that has been reported for centuries during previous Venus transits. In 1761, French astronomer Chappe d’Auteroche was first to record an observation of a bright arc around the dark edge of the planet as it sunk into the sun's limb, beginning the transit -- a period known as "ingress." The brightening was also visible as Venus completed its transit, emerging from the limb -- a period known as "egress."

d'Auteroche correctly deduced that this brightening, or "aureole," was caused by the presence of an atmosphere refracting sunlight around the planet.

Since those pioneering days, Venus aureole have been repeatedly recorded by observers on the ground and by space telescopes -- like observations by NASA's Transition Region And Coronal Explorer (TRACE) solar observatory during the 2004 transit, shown top. As it turns out, far from just being a curiosity, science can be done by observing this beautiful event.

Paolo Tanga, an astronomer from the Observatory of Côte d'Azur in Nice, France, describes the "Aureole Effect" in an entry for the Transit of Venus Project website, pointing out that the luminescent crescent isn't uniform and that, until recently, it was a bit of a mystery. Often, just as Venus is about to pass into the solar limb (at ingress) and after it has passed out of the limb (at egress), a bright spot emerges from the aureole. So what causes it?

"Only in the 20th century, when the rotational properties of the planet were known, the astronomers were able to verify that this spot coincides roughly with one of the planet’s poles," says Tanga.

Basically, as Venus begins to pass in front of the sun, some sunlight is refracted around the planet's atmosphere, creating the luminescent crescent of the aureole. The physics of refraction is very well known, as is the composition of Venus' atmosphere. The amount of refraction applied to a beam of light is greatly influenced by the density of the medium (in this case atmospheric gases), which is affected by atmospheric temperature.

As we know the rotational properties of Venus, astronomers are able to deduce that the persisting bright spot of the aureole is located over the poles. This means that some property of the atmosphere above Venus' poles is changing the angle of refraction through the atmosphere. As it turns out, this modification is caused by a temperature difference in Venus' upper polar atmosphere -- in a mysterious region known as the mesosphere.

Read more at Discovery News

Jun 3, 2012

Where Have All the Hummingbirds Gone?

The glacier lily as it's called, is a tall, willowy plant that graces mountain meadows throughout western North America. It flowers early in spring, when the first bumblebees and hummingbirds appear.

Or did.

The lily, a plant that grows best on subalpine slopes, is fast becoming a hothouse flower. In Earth's warming temperatures, its first blooms appear some 17 days earlier than they did in the 1970s, scientists David Inouye and Amy McKinney of the University of Maryland and colleagues have found.

The problem, say the biologists, with the earlier timing of these first blooms is that the glacier lily is no longer synchronized with the arrival of broad-tailed hummingbirds, which depend on glacier lilies for nectar.

By the time the hummingbirds fly in, many of the flowers have withered away, their nectar-laden blooms going with them.

Broad-tailed hummingbirds migrate north from Central America every spring to high-mountain breeding sites in the western United States. The birds have only a short mountain summer to raise their young. Male hummingbirds scout for territories before the first flowers bloom.

But the time between the first hummingbird and the first bloom has collapsed by 13 days over the past four decades, say Inouye and McKinney. "In some years," says McKinney, "the lilies have already bloomed by the time the first hummingbird lands."

The biologists calculate that if current trends continue, in two decades the hummingbirds will miss the first flowers entirely.

The results are reported in a paper in the current issue of the journal Ecology. In addition to McKinney and Inouye, co-authors of the paper are Paul CaraDonna of the University of Arizona; Billy Barr of the Rocky Mountain Biological Laboratory in Crested Butte, Colo.; David Bertelsen of the University of Arizona; and Nickolas Waser, affiliated with all three institutions.

"Northern species, such as the broad-tailed hummingbird, are most at risk of arriving at their breeding sites after their key food resources are no longer available, yet ecologists predict that species will move northward as climate warms," says Saran Twombly, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.

"These conflicting pressures challenge society to ensure that species don't soon find themselves without a suitable place to live."

Broad-tailed hummingbirds that breed farther south have fewer challenges.

"In Arizona, for example," says Inouye, "there's no obvious narrowing of the timing between the first arriving males and the first blooms of, in this case, the nectar-containing Indian paintbrush."

Higher latitudes may be more likely to get out of sync ecologically because global warming is happening fastest there.

Read more at Science Daily

American 'Cannibal Apocalypse'?

A recent spate of sensational cannibalism cases is making headlines. On May 26, in Miami, Florida, Rudy Eugene was high on drugs when he attacked a homeless man, Ronald Poppo, biting his victim's face and ripping his flesh until police shot and killed him.

As if that crime wasn't bizarre enough, a second case emerged a few days later when Alexander Kinyua, a student at Maryland's Morgan State University, allegedly confessed to killing, dismembering, and eating his roommate's heart and brain. Kinyua's motive is unclear, though many believe it is related to African belief in magic. Kinyua is from Kenya in East Africa, where there is strong belief that body parts (including those of albinos) have magical abilities.

As Jennifer Viegas recently pointed out here on Discovery News, though human cannibalism is rare in the modern world, it still persists. Viegas described a case in Brazil where two suspects confessed to murdering at least two women, eating parts of their bodies, and using the rest to make meat pies sold on a streetcorner in Sao Paulo. One of the killers stated that the murder and cannibalism was driven by religious duty.

Cannibalism has occasionally been practiced by murderers; serial killer Jeffrey Dahmer infamously killed and ate parts of several victims during the late 1980s and early 1990s, and in 1994 an Ohio man named Henry Heepe killed his mother, dismembered her, and cooked some of her body parts. Heepe said he killed his mother because he believed she was a "vampire devil."

Perhaps the strangest case was that in 2006 of German Armin Meiwes, who solicited for -- and found -- a willing victim to cannibalize. Meiwes posted an online ad "looking for a well-built 18- to 30-year-old to be slaughtered and then consumed." A man named Bernd Jürgen Brandes volunteered, and Meiwes ate Brandes over the course of the next ten months. Despite his victim's participation Meiwes was convicted of murder and sentenced to life in prison.

The idea that consuming another's flesh (or taking another person's body parts) gives the cannibal or killer some special power or ability is ancient. Tribes in South America, Indonesia, and elsewhere practiced headhunting into the twentieth century, often taking limbs and heads as war trophies and sources of magic. This theme can be found in mainstream religion as well; for example in Roman Catholicism bread and wine are believed to literally -- not just figuratively -- become the flesh and blood of Jesus upon consumption (in a process called transubstantiation).

There are many myths about humans eating human flesh. While some historians believe that cannibalism was an accepted practice in some tribal societies, this view has been disputed by William Arens, an anthropologist at the State University of New York at Stony Brook.

In his 1980 book The Man-Eating Myth (Oxford University Press 1980), Arens challenges the claim that that cannibalism was ever a socially approved custom anywhere in the world. Arens doesn't deny that cannibalism has been practiced, but questions the assumption that it was ever routine, ritualized, or acceptable. Instead, incidents of cannibalism were driven by famine, mental illness, or aberrant belief in mysticism or religion.

As it turns out, one of the most famous cases of American cannibalism may not be true. In 2006, archaeologists who researched Alder Creek, Nevada -- the site where the ill-fated Donner pioneer party became trapped during the winter of 1846 and allegedly resorted to cannibalism -- announced that "there's no physical evidence that the family who gave the Donner Party its name had anything to do with cannibalism." The findings did not disprove the sensational stories that emerged after the survivors were rescued, but found no physical evidence to support the claims.

Read more at Discovery News