Sep 20, 2014
Fairness is a social ideal that cannot be measured, so to understand the evolution of fairness in humans, Dr. Sarah Brosnan of Georgia State's departments of Psychology and Philosophy, the Neuroscience Institute and the Language Research Center, has spent the last decade studying behavioral responses to equal versus unequal reward division in other primates.
In their paper, published in the journal Science, she and colleague Dr. Frans de Waal of the Yerkes National Primate Research Center and the Psychology Department at Emory University, reviewed literature from their own research regarding responses to inequity in primates, as well as studies from other researchers. Although fairness is central to humans, it was unknown how this arose. Brosnan and de Waal hypothesize that it evolved, and therefore elements of it can be seen in other species.
"This sense of fairness is the basis of lots of things in human society, from wage discrimination to international politics," Brosnan said. "What we're interested in is why humans aren't happy with what we have, even if it's good enough, if someone else has more. What we hypothesize is that this matters because evolution is relative. If you are cooperating with someone who takes more of the benefits accrued, they will do better than you, at your expense. Therefore, we began to explore whether responses to inequity were common in other cooperative species."
Brosnan and de Waal began their studies of fairness in monkeys in 2003, becoming the first in the field to report on this subject for any non-human species, Brosnan said. This paper, titled "Monkeys Reject Unequal Pay," was published in Nature.
In this study, brown capuchin monkeys became agitated and refused to perform a task when a partner received a superior reward for that same task. Since then, Brosnan has tested responses to inequity in nine different species of primates, including humans. She has found that species only respond to inequity when they routinely cooperate with those who are not related to them.
However, responding to getting less than a partner is not the only aspect of fairness. For a true sense of fairness, it also matters if you get more. Brosnan and de Waal hypothesize that individuals should be willing to give up a benefit in order to reach equal outcomes and stabilize valuable, long-term cooperative relationships. Thus far, this has only been found in humans and their closest relatives, the apes.
Read more at Science Daily
Rhinorex, which translates roughly into "King Nose," was a plant-eater and a close relative of other Cretaceous hadrosaurs like Parasaurolophus and Edmontosaurus. Hadrosaurs are usually identified by bony crests that extended from the skull, although Edmontosaurus doesn't have such a hard crest (paleontologists have discovered that it had a fleshy crest). Rhinorex also lacks a crest on the top of its head; instead, this new dinosaur has a huge nose.
Terry Gates, a joint postdoctoral researcher with NC State and the North Carolina Museum of Natural Sciences, and colleague Rodney Sheetz from the Brigham Young Museum of Paleontology, came across the fossil in storage at BYU. First excavated in the 1990s from Utah's Neslen formation, Rhinorex had been studied primarily for its well-preserved skin impressions. When Gates and Sheetz reconstructed the skull, they realized that they had a new species.
"We had almost the entire skull, which was wonderful," Gates says, "but the preparation was very difficult. It took two years to dig the fossil out of the sandstone it was embedded in -- it was like digging a dinosaur skull out of a concrete driveway."
Based on the recovered bones, Gates estimates that Rhinorex was about 30 feet long and weighed over 8,500 lbs. It lived in a swampy estuarial environment, about 50 miles from the coast. Rhinorex is the only complete hadrosaur fossil from the Neslen site, and it helps fill in some gaps about habitat segregation during the Late Cretaceous.
"We've found other hadrosaurs from the same time period but located about 200 miles farther south that are adapted to a different environment," Gates says. "This discovery gives us a geographic snapshot of the Cretaceous, and helps us place contemporary species in their correct time and place. Rhinorex also helps us further fill in the hadrosaur family tree."
Read more at Science Daily
Sep 19, 2014
The 24th edition of the annual Ig Nobel Prizes were handed out Thursday night to winners from across the world by genuine Nobel laureates in Cambridge, Mass.
The awards showcase "achievements that first make people laugh, and then make them think," said the organizers. The ceremony at Harvard's Sanders Theater was attended by hundreds and broadcast live online.
The winners are serious scientists whose work is generally considered only unintentionally funny.
Japanese researchers won the physics prize for measuring the amount of friction between a shoe and a banana skin, and between a banana skin and the floor when a person steps on the discarded fruit peel.
Scientists in China and Canada won a neuroscience prize for trying to understand what happens in the brains of people who see the face of Jesus in a piece of toast.
The authors come from Beijing Jiaotong University's School of Computer and Information Technology, Xidian University, the Institute of Automation Chinese Academy of Sciences in Beijing, and the University of Toronto.
Australia, Britain and the United States shared the psychology prize for collecting evidence that people who habitually stay up late are, on average, more self-admiring, manipulative and psychopathic than early risers.
The public health prize was shared by the Czech Republic, India, Japan and the United States for investigating whether it is mentally hazardous to own a cat.
The Czech Republic also joined Germany and Zambia in winning the biology prize for documenting that when dogs defecate and urinate, they prefer to align their body axis with Earth's north-south geomagnetic field lines.
Italy took the art prize for measuring the relative pain people suffer while looking at an ugly rather than a pretty painting.
The Italian government's National Institute of Statistics walked away with the economics prize for increasing the official size of its national economy by including revenue from prostitution, illegal drug sales, smuggling, and other unlawful financial transactions between willing participants, organizers said.
India and the United States shared the medicine prize for treating "uncontrollable" nosebleeds with strips of cured pork.
Germany and Norway won the Arctic science award for testing how reindeer react to seeing humans who are disguised as polar bears.
And Spanish researchers took home the nutrition prize for a study titled "Characterization of Lactic Acid Bacteria Isolated from Infant Feces as Potential Probiotic Starter Cultures for Fermented Sausages."
Read more at Discovery News
Ornate jewellery and intricately decorated daggers, known today as the Stonehenge treasure, were unearthed in 1808 from a burial mound known as Bush Barrow near the iconic monument.
The burial contained the skeleton of a clan leader who lived almost 4,000 years ago. He was laid to rest in regal splendor with the objects that showed his power and authority.
On his chest was a gold lozenge that fastened his cloak and would have glinted in the sun, while a bronze dagger adorned with an intricate design hung from his belt.
Now on permanent display at the Wiltshire Museum in Devizes, 15 miles north of the megalithic stone circle, the Stonehenge treasure was re-examined as part of a BBC documentary. On this occasion, experts considered for the first time the human cost of Bronze Age micro gold-working.
The ultra-fine craftwork was produced nearly 4,000 years ago — more than 1,000 years before the invention of any form of magnifying glass — and entailed extremely tiny components such as microscopic gold pins and gold wires.
“Only children and teenagers, and those adults who had become myopic naturally or due to the nature of their work as children, would have been able to create and manufacture such tiny objects,” Ronald Rabbetts, one of the Britain’s leading authorities on the optics of the human eye, said.
The handle of the Bush Barrow dagger was originally decorated with 140,000 tiny studs, each thinner than a human hair. They were set into the wood at a density of over 1,000 per square centimeter to create a zig-zag pattern.
“The size of the studs clearly shows they are too small for adults to have made and set into the dagger handle,” David Dawson, director of the Wiltshire Museum, told Discovery News.
He estimated the entire operation to produce the dagger’s intricate decoration, from wire manufacture and stud-making to hole-making and stud positioning, would have taken at least 2,500 hours to complete and would have left the workers almost blind. Today only fragments of the original wooden dagger handle survive.
Experts believe children were trained and worked in Brittany, where some 20 daggers with handles decorated with tiny gold pins have been found.
“The Bush Barrow dagger is far and away the most intricate, but the numbers suggest that the daggers were made in Brittany — where there are also sources of gold. Metal ingots were traded across the English Channel, but the dagger may have been a gift from one chieftain to another,” Dawson said.
Read more at Discovery News
Data records spanning almost 600 years have shown that the strength of coastal upwelling off the west coast of North America has become more variable since 1950. Researchers pieced together this long-term look at ocean trends from an unlikely source: tree rings.
Coastal upwelling happens when winter winds lift deep, nutrient-rich waters up to the shallow layers of the sea. These nutrients fuel phytoplankton growth in the sunlit surface waters. Since 1950, California has experienced more winters with weak coastal upwelling than in the last five centuries. Researchers found that years with weak upwelling were associated with slower growth in fish populations and lower reproduction rates for seabirds, the researchers said.
But the weather pattern that causes the coastal upwelling also blocks storms from coming ashore. This causes drought and stunts the growth of trees. Blue oak trees along the California coast are particularly sensitive to winter precipitation, Bryan Black, assistant professor of marine science at the University of Texas at Austin, told Live Science.
Trees grow a new ring every year. By looking at a cross-section cut through the bark of a tree, scientists can count up the rings and determine a tree's age. Differences in the ring sizes reveal good seasons and bad seasons, with a thick ring signaling that the tree had a good growing season. The researchers found an inverse relationship between tree growth and the well-being of the marine ecosystem, Black explained.
"The winters we see robust growth in the trees, we see poor growth in the marine ecosystem," Black said.
Coastal upwelling happens during the winter when a strong, high-pressure weather system develops along the west coast of the continent. The system spins clockwise and brings in winds from the north. That spin combines with the rotation of the Earth to move the waters off shore and stir up clouds of nutrients. Phytoplankton at the surface rely on this seasonal influx of nutrients. These organisms are the backbone of the marine ecosystem and support huge populations of fish and seabirds.
Some variation in coastal upwelling from year to year is normal, but most direct data records don't go back more than 70 years. This makes it difficult for marine scientists to spot any long-term trends. By studying tree-ring patterns, however, researchers can piece together a much longer record of how coastal upwelling has changed.
To determine how upwelling influenced marine life, the researchers used data on yearly fish population growth since the 1940s, along with data on seabird egg laying and the survival of baby seabirds since the 1970s. By comparing the tree-ring data to the fish and seabird statistics, the researchers found that years with weak upwelling and lots of tree growth correlated with years when fish and seabird populations suffered.
Based on tree ring measurements taken by David Stahle, a tree ring expert and professor of geoscience at the University of Arkansas in Fayetteville, the team found that four out of the 10 weakest upwelling years in the past 600 years occurred after 1950. Seven out of 10 weakest years have happened since 1850.
While the data show there are years in which bird and fish populations don't fare well, "it's not necessarily indicative of a long-term decline," Black said, since the bird and fish populations usually bounce back within a couple years after a bad season.
Black said it's unclear if climate change is causing the recent high variation in coastal upwelling.
"California climate can be very extreme," Black said. "The 20th century is particularly variable in the context of the last few centuries, but it's not necessarily unique to history."
Read more at Discovery News
|Those are parasitic worms dancing in the snail’s eyes. Dancing in the snail’s eyes. It’s like Saturday Night Fever, only with more blindness and less chest hair.|
Mother Nature, you see, has cooked up an even more sadistic punishment for the humble snail. It’s called Leucochloridium, and it’s a parasitic worm that invades a snail’s eyestalks, where it pulsates to imitate a caterpillar (in biology circles this is known as aggressive mimicry—an organism pretending to be another to lure prey or get itself eaten). The worm then mind-controls its host out into the open for hungry birds to pluck out its eyes. The worm breeds in the bird’s guts, releasing its eggs in the bird’s feces, which are happily eaten up by another snail to complete the whole bizarre life cycle.
It’s an existence that’s as brilliant as it is strange. But while science has known about Leucochloridium for more than a century, it was only in 2013 that biologist Tomasz Wesołowski of Poland’s Wrocław University confirmed the worm is indeed capable of manipulating its snail hosts. (Specifically, amber snails—like many other mind-controlling parasites, it’s highly species-specific, that is, it’s unable to manipulate the behavior of more than one species.)
Inside the snail, Wesołowski says, the whole grand show begins as the ingested egg develops into what is known as a sporocyst, “which looks like a bunch of whitish tissue, seated mostly in the liver of the snail. And then it grows like a tumor, more or less.” It doesn’t have a mouth, so like many parasitic worms, such as the horsehair worm that infects and mind-controls crickets, it simply sits around soaking up the snail’s hard-earned nutrients through its skin. Like a clubber downing vodka Red Bulls, it’s gonna need energy if it’s gonna dance.
As if it weren’t enough of a meany-head, Leucochloridium also castrates its host. This makes good evolutionary sense: Energy normally spent producing eggs and sperm (snails are hermaphrodites) goes toward sustaining the worm. So, pumped full of the requisite nutrition, the sporocyst sends out branches that tunnel through the snail’s body and into its eyestalks, also known as tentacles, where it forms a brood sac full of larvae. It’s these larvae that eventually go all disco.
Now, it’s worth talking for a moment about the physiology of snail peepers. At the tip of the tentacle sits a rudimentary eyespot, which is really only good for discerning light and dark. The snail can’t see color, and the eyestalk doesn’t have the muscles required to focus. But what the snail does have are muscles that retract the tentacles, which it can then redeploy by pumping them full of fluid.
|Sketches of Leucochloridium. Notice the thin trailing bit, which would lead back to the sporocyst in the snail’s liver.|
The worm, though, has a problem: Snails are largely nocturnal, and passerine birds, which hunt by sight, most certainly are not. So once the Leucochloridium has sufficiently developed in the eyestalk, it begins manipulating the behavior of its host, forcing it out into the many dangers of the light of day, where predators swarm and the sun rapidly desiccates. It’s probably using chemicals, but how it’s able to pull off this incredible feat remains a mystery, as do the chemical secrets of any number of other zombifying parasites (though scientists are making progress in decoding the compounds that the Ophiocordyceps fungus uses to assume control over ants).
So quite weirdly the Leucochloridium worms must themselves know the difference between night and day. “What is most amazing is that these brood sacs are pulsating only in daylight,” said Wesołowski. “They have no photosensitive anything—no trace of, say, any nervous system, no sense organs. Nothing. Still they recognize when it’s worth pulsating and when it’s not worth pulsating. So that’s very, very unusual. Nobody knows how it’s achieved.”
Wesołowski also found infected snails are up to three times as active as their non-zombified peers: He even observed one traveling a full 3 feet in just 15 minutes. That may not sound impressive to you, what with your fancy legs and all, but “for a snail, that’s a race,” he said. In addition, he found that the worms convinced their host to stay “on the upper parts of plants and higher elevated places. So all of this combined made them easier to be spotted by foraging birds.”
|An amber snail wondering why it even bothers to get out of bed in the morning.|
And so the cycle begins anew as the worms grow and reproduce in the bird’s gut. Strangely, though, Leucochloridium and other so-called trematode worms (all of which are parasitic, though not necessarily zombifiers) seem to have figured out how to skip a step. They belong to the flatworm phylum, whose members typically go through two intermediate hosts on their way to their primary host, according to Wesołowski—the former for Leucochloridium just being the snail and the latter the bird. The intestinal worm Metagonimus yokogawai, for instance, starts in snails, which are eaten by fish, which if not cooked properly by humans ends up in our guts.
Read more at Wired Science
Sep 18, 2014
She was not mummified, her body simply being wrapped in a mat. When archaeologists uncovered her remains they found she wore "a very complex coiffure with approximately 70 extensions fastened in different layers and heights on the head," writes Jolanda Bos, an archaeologist working on the Amarna Project, in an article recently published in the Journal of Egyptian Archaeology.
Researchers don't know her name, age or occupation, but she is one of hundreds of people, including many others whose hairstyles are still intact, who were buried in a cemetery near an ancient city now called Amarna.
This city was constructed as a new capital of Egypt by Akhenaten (reign ca. 1353-1335 B.C.), a pharaoh who unleashed a religious revolution that saw the Aten, a deity shaped as a sun disk, assume supremacy in Egyptian religion. Akhenaten ordered that Amarna be constructed in the desert and that images of some of Egypt's other gods be destroyed. Amarna was abandoned shortly after Akhenaten's death, and today archaeologists supported by the Amarna Trust are investigating all aspects of the ancient city, including the hairstyles its people wore.
Bos is leading the hairstyle research, and the woman with 70 extensions leaves her puzzled.
"Whether or not the woman had her hair styled like this for her burial only is one of our main research questions," said Bos in an email to Live Science. "The hair was most likely styled after death, before a person was buried. It is also likely, however, that these hairstyles were used in everyday life as well and that the people in Amarna used hair extensions in their daily life."
Many of the other skulls Bos analyzed also had hair extensions. One skull had extensions made of gray and dark black hair suggesting multiple people donated their hair to create extensions.
As Bos analyzed a selection of 100 recently excavated skulls (of which 28 still had hair) from the Armana cemetery, she noticed the people who lived in the ancient city had a wide variety of hair types. They range "from very curly black hair, to middle brown straight," she noted in the journal article, something "that might reflect a degree of ethnic variation."
Those skulls with brown hair often had rings or coils around their ears, a style that was popular at Amarna, she found. Why people in this city liked it is unknown. "We still have no idea. This is of course one of the answers we are still trying to find from the record," said Bos in the email.
People in the city also seemed to be fond of braids. "All braids found in the coiffures were simple and of three strands, mostly 1 cm [0.4 inches] wide, with strands of approximately 0.5 cm [0.2 inches] when tightly braided," Bos writes in the journal article.
People at Amarna also liked to keep their hair short. "Braids were often not more than 20 cm [7.9 inches] long, leaving the hair at shoulder length approximately," Bos added. "The longest hair that was found consisted of multilayered extensions to a length of approximately 30 cm [11.8 inches]."
Fat was used to help create all the hairstyles Bos found, something that would have helped keep the hair in one piece after death. More research is needed to determine whether the fat was from animals. A textile found on each of the skulls may have been used to cover part of the head.
Read more at Discovery News
Until now, the mainstream theory was that Europeans descended from early farmers who moved into Europe from the Middle East about 7,500 years ago, and local hunter-gatherers they interbred with.
But a DNA analysis in the journal Nature says there was a third group in the mix: people from northern Eurasia.
The finding means that North Eurasians -- who inhabited a vast swathe of land stretching across much of Russia and northern Asia -- contributed to the gene pool both in Europe and North America.
Their influence on the Americas were borne out in previous studies which showed that North Eurasians crossed to modern-day Alaska more than 15,000 years ago via an "ice bridge" that connected islands in the Bering Strait at the time.
"What we find is unambiguous evidence that people in Europe have all three of these ancestries," said David Reich of Harvard Medical School, who led the study with Johannes Krause at Germany's University of Tuebingen.
The 100-strong team of scientists drew on a vast collection of resources.
They unravelled DNA teased from nine ancient skeletons found in Sweden, Luxembourg and Germany. The remains were those of eight hunter-gatherers who lived about 8,000 years ago, before the advent of agriculture, and one farmer from about 7,000 years ago.
"There was a sharp genetic transition between the (era of) hunter-gatherers and the farmers, reflecting a major movement of new people into Europe from the Near East," said Reich.
The genomes were overlaid with the genetic codes of 2,300 present-day people living all over the world.
Read more at Discovery News
|Two Oxytricha cells mating.|
Unlike humans and most other organisms on Earth, Oxytricha doesn’t have sex to increase its numbers. It has sex to reinvent itself.
When its food is plentiful, Oxytricha reproduces by making imperfect clones of itself, much like a new plant can grow from a cutting. “If they’re well fed, they won’t mate,” said Laura Landweber, a molecular biologist at Princeton University and lead author of a recent study on Oxytricha genetics. But when Oxytricha gets hungry or stressed, it goes looking for sex.
When two cells come together (as in the image above), the ultimate result is: two cells. “They’ve perfected the art of sex without reproduction,” Landweber said. The exterior of the two cells remains, but each cell swaps half of its genome with the other. “They’re entering into this pact where each one is going to be 50 percent transformed,” Landweber said. “They emerge with a rejuvenated genome.”
In size, Oxytricha’s genome is roughly comparable to ours. It has about 18,500 genes, compared to 20,000 or so for humans. But that’s one of the few things we have in common with this pond-dwelling protist.
Unlike the cells of plants and animals (fungi too, for that matter), an Oxytricha cell has at least two nuclei. “You can see them under the microscope if you stain for DNA,” Landweber said. One nucleus contains a working copy of the genome—all the DNA it uses to make the RNA and proteins essential for everyday life. Last year, Landweber’s team discovered that the DNA in Oxytricha’s working nucleus is partitioned into approximately 16,000 “nanochromosomes,” most containing just a single gene. It’s a staggering number—most common plants and animals have somewhere between a dozen and a hundred chromosomes (we humans have 23 pairs).
In a recent paper in the journal Cell, Landweber and colleagues describe an even stranger arrangement in Oxytricha’s second nucleus, which contains the genes it will pass on to the next generation. In this nucleus, Oxytricha has about a hundred chromosomes, made up of a total of about 225,000 pieces of DNA. Tens of thousands of these pieces are encrypted: The letters of the genetic code are flipped or scrambled relative to the corresponding copy in the working nucleus.
When two cells mate, each partner transfers a set of these chromosomes to the other. Then, each cell breaks the chromosomes down into their constituent 225,000 pieces and uses those pieces to assemble a new working genome, decrypting the encrypted pieces along the way.
“It really is like it’s running an algorithm, and it’s a cellular computer,” Landweber said.
In the process of rebuilding its genome, which takes about 2 days, each cell discards more than 90 percent of its DNA to end up with a newly remodeled set of 16,000 nanochromosomes in its working nucleus. The final result for both cells is a new genome that incorporates pieces from its original stash of DNA as well as new pieces of DNA from its partner.
It’s “arguably the most complex genome architecture of any known eukaryote,” the scientists write. (Eukaryotes are cells with nuclei, which includes just about everything except bacteria).
The reason for all this complexity is a mystery. One possibility, says Landweber, is that encrypting its DNA helps Oxytricha thwart viruses that might otherwise take up residence in its genome, she says. Or maybe its ability to scramble, unscramble, and rebuild its genome let Oxytricha and its ancestors create new genetic variations that helped them survive whatever hardships they’ve encountered in their 2 billion years or more on Earth.
Read more at Wired Science
|“Here, have this bread, so as not to eat me instead.”|
It worked. The man was able to lead the giant to a small island offshore, where the great captain waited. Describing the scene was a scholar along for the journey, Antonio Pigafetta, who kept a diary of the journey that was later turned into the book Magellan’s Voyage: A Narrative Account of the First Circumnavigation: “When he was before us, he began to marvel and to be afraid, and he raised one finger upward, believing that we came from heaven. And he was so tall that the tallest of us only came up to his waist,” and had a big, booming voice. The illustration above proves it—Patagonia was once inhabited by giants that positively dwarfed the heavenly Europeans that would come to conquer them.
Alright, maybe that isn’t airtight evidence. But it could well be that the people Magellan encountered, the Tehuelche, were indeed enormous, and that therefore this myth has some grounding in reality. And our trusty explorer would be damned if he wasn’t going to try to bring back evidence in pretty much the most obnoxious way you could imagine.
After several weeks with the tribe, Magellan hit upon a scheme: He’d kidnap two of them and take them back to Spain to prove he had discovered giants. “But this was by a cunning trick, for otherwise [the giants] would have troubled some of our men.” Magellan gave them all manner of metal goods to fool around with—mirrors, scissors, bells—so they wouldn’t mind at all when he slapped cuffs and chains on their legs. “Whereat these giants took great pleasure in seeing these fetters, and did not know where they had to be put, and they were grieved that they could not take them in their hands” because their mitts already were full of other trinkets.
Magellan, though, lost his evidence during the long haul back to Spain. The giants didn’t survive. But what Magellan and Pigafetta did bring back was the tale and the new name of the land of the giants, Patagonia, the etymology of which is still unclear. Some have argued it means “Land of the Big Feet,” from “pata,” Spanish for foot. More likely, though, Magellan picked up the name from a popular novel at the time, Primaleon, which featured a race of wild people called the Patagonians.
|A map by Diego Gutiérrez from 1562, showing the Patagonian giants and some mermaids playing frisbee, apparently.|
“Magellan was not altogether deceived in naming these giants, for they generally differ from the common sort of man both in stature, bigness and strength of body, as also in the hideousness of their voices: but they are nothing so monstrous and giant-like as they were represented, there being some English men as tall as the highest we could see, but peradventure the Spaniards did not think that ever any English man would come hither to reprove them, and therefore might presume the more boldly to lie.”
|You may have noticed by now that most illustrations of the Patagonian giants involve Europeans handing them things. It was the map above that likely influenced them, including this drawing of Commodore John Byron conversing with a Patagonian woman.|
“Popular interest in Patagonian giants waned as scientific reports began to appear,” writes Sturtevant. “Some 19th century estimates or measurements of individuals were still high,” upwards of 7 feet. But better samples of Tehuelche men brought them down to around 6 feet tall, perfectly reasonable for a human being but entirely unimpressive for a giant. “If we accept the lowest (and least well documented) of these means based on modern measurements of males series,” he adds, “the Tehuelche are nevertheless among the tallest populations known anywhere in the world.” By contrast, male Europeans like Magellan in the 16th through 18th centuries would have measured in the low-5-foot range. Their imaginations, though, apparently outgrew their small stature.
But why, then, do human beings vary so much in their height? There is of course the factor of nutrition, but a much more subtle influence is at work here.
|The tallest man who ever lived, Robert Wadlow, with his father, who appears grumpy probably because of all the money he had to spend on his son’s giant clothes.|
There’s also the possibility that the Tehuelche man who Magellan and his crew claimed was so tall they only reached his waist suffered from a disorder of the pituitary gland. This releases runaway levels of the human growth hormone, as it did in the tallest man in recorded history, the 8-foot-11 Robert Wadlow. Indeed, the photograph above shows Robert and his 5-foot-11 father—a man far taller than the average male in the 1500s—coming up to his son’s waist.
The human body, though, is simply not meant to grow to such heights. Pituitary giants typically have much shorter life spans than the average human because their hearts, even though proportionally enlarged, struggle to pump blood through their bodies. Wadlow himself had little sensation in his feet, eventually dying at just 22 from an infected blister that he never felt forming.
Read more at Wired Science
Sep 17, 2014
The new findings, published in the journal Biology Letters, are troubling, given that one effect of the human consumption of fossil fuels is to make ocean water more acidic. If fossil fuel burning continues as is, sharks may face even more challenges than they do today — when a quarter of species are already at risk of extinction.
"Usually when you expose a fish to some kind of environmental stressor, they usually acclimate to that stressor, and that makes them less vulnerable to that stressor," said study researcher Fredrik Jutfelt, an animal physiologist at the University of Gothenburg in Sweden. "But here, it seemed like this high CO2 [carbon dioxide] continued to be a stressor to these sharks for quite a long time."
The world's oceans absorb carbon dioxide from the atmosphere, a process that decreases the pH (a measure of how acidic or basic a substance is) of ocean water, turning it more acidic. According to the National Oceanic and Atmospheric Administration (NOAA), the pH of ocean surface water has fallen by 0.1 on the 14-point scale since the beginning of the Industrial Revolution. That drop on the pH scale translates to surface water that's 30 percent more acidic than before.
Today, ocean water has a pH of about 8.1, Jutfelt told Live Science, and the atmosphere contains about 400 parts per million of carbon dioxide. If humans continue to load the atmosphere with carbon, this concentration is expected to rise to about 1,000 parts per million by 2100. In that scenario, the pH of ocean water is expected to drop to about 7.7 or 7.8. The pH scale runs from 0 (most acidic) to 14 (most basic), with a pH of 7 being neutral.
Studies of bony fishes have found that some species react catastrophically to acidified water, while others are quite tolerant, Jutfelt said. But hardly anyone had examined the effects of ocean acidification on sharks and rays, fish known for their cartilaginous bones.
Jutfelt and his colleague Leon Green, also of the University of Gothenburg, borrowed 20 small-spotted catsharks (Scyliorhinus canicula), from a local aquarium. This small, common bottom-dweller is found throughout the Atlantic Ocean and Mediterranean Sea. They put half of the sharks in tanks filled with typical ocean water with a pH of 8.1, and half in tanks filled with acidified ocean water with a pH of about 7.7 for four weeks.
After this period, the researchers tested the sharks on a variety of physiological responses and behaviors, including their blood pH and oxygen consumption rates. They also took video of the sharks at night, when these nocturnal animals are most active.
Although the CO2-exposed sharks' metabolisms were normal, the researchers found more sodium and bicarbonate ions in their blood, apparently a molecular adjustment made to keep the sharks' blood pH stable in the more-acidic water. Most strikingly, however, was the discovery that the sharks in the acidified water exhibited odd nighttime behavior.
"The control sharks, they would have these many starts and stops throughout the night. They would swim for a few seconds, or up to a minute, maybe, and then stop," Jutfelt said. "But the CO2-exposed sharks, they kept swimming for longer time periods. Some of them swam for an hour continuously."
This continuous swimming behavior could have been a result of altered ion concentrations in the brain, Jutfelt said. Alternatively, the sharks could have sensed that the water was too acidic and kept swimming in hopes of finding better-quality water elsewhere. Surprisingly, Jutfelt said, the sharks kept up this behavior change four to six weeks after first being introduced to the acidified water.
"They don't seem to be able to completely acclimate," he said.
Read more at Discovery News
Depicted by William Shakespeare as a bloodthirsty usurper, Richard ruled England from 1483 to 1485. He was killed in 1485 in the Battle of Bosworth, which was the last act of the decades-long fight over the throne known as War of the Roses. England’s last king to die in battle, he was defeated by Henry Tudor, who became King Henry VII.
The king’s twisted skeleton was found two years ago under a car park by archaeologists from the University of Leicester.
The skeleton, showing a severe spinal scoliosis, was widely examined by researchers.
The latest investigation, carried out by researchers at the University of Leicester, focused on the king’s final moments.
Modern forensic techniques, including whole body CT scans and micro-CT imaging, were used to examine the 500-year-old skeleton for trauma. The aim was to draw the most likely scenario of Richard’s death and determine which of the king's wounds might have proved fatal.
The researchers identified 11 wounds. Nine were found to the skull, suggesting Richard had removed or lost his helmet, and two to the rest of the skeleton. All injuries were consistent with the types of weapons used in the late medieval period.
"The most likely injuries to have caused the king's death are the two to the (underside) of the skull -- a large sharp force trauma possibly from a sword or staff weapon, such as a halberd or bill, and a penetrating injury from the tip of an edged weapon,” said Guy Rutty, study co-author, from the East Midlands Pathology Unit at the University of Leicester.
Both the head wounds described by Rutty would have caused hemorrhage, injury to the brain or air embolus, leading to death within a short time. Most probably, it was the penetrating injury that went from the base of the skull through to the inner surface of the skull that led to immediate death.
According to the researchers, the head trauma confirms some near-contemporary accounts of the battle, which reported the king abandoned his horse after it became stuck in a mire and was killed while fighting his enemies.
“The injuries are highly consistent with the body having been in a prone position or on its knees with the head pointing downwards,” researchers wrote in the journal The Lancet.
“There were no defensive injuries to the arms or hands suggesting he was still armored at the point of death,” Sarah Hainsworth, professor of materials engineering at the University of Leicester, told Discovery News.
The injuries represent either a sustained attack or an attack by several assailants.
“It is possible that he suffered a simultaneous attack from several assailants,” Hainsworth said.
She noted that at least three weapons were involved in causing injury to the skull. A rondel dagger was most probably used to create a square-shaped injury to the top of the skull, while a number of "shaving type" injuries were caused by a sharp bladed weapon such as a dagger or sword.
Of the two potentially fatal wounds to the base of the skull, one was most likely caused by a pole weapon such as a bill or halberd. The other injury, penetrating through the skull from the base to the inside, was again likely caused by a sword or dagger.
“It is therefore likely that more than one person was involved if each person held one weapon. But we can't say exactly how many people were there or how fast the injuries were sustained,” Hainsworth said.
In addition to the injuries to the base of the skull, the researchers found another potentially fatal wound. It was inflicted to the pelvis, one of the most vulnerable areas to attack in a medieval battle.
But Richard was wearing his armor, so it’s likely he was already dead when a fine-bladed weapon penetrated the right buttock and traversed the right side of the pelvic cavity.
“The most probable mode of injury is after Richard’s armor had been removed,” the researchers said.
Indeed, contemporary accounts of the battle describe Richard’s body as being slung over the back of a horse suffering insults.
“The angle of the injury to the pelvis is highly consistent with such treatment,” the researchers wrote.
The pelvis injury adds to other wounds, such as three face injuries, which were most likely caused after death.
Read more at Discovery News
Consider M60-UCD1, an ultra-compact dwarf galaxy located about 55 million light-years from Earth in the Virgo cluster. Despite its diminutive stance, the galaxy appears to harbor a supermassive black hole, one more fitting in a galaxy 80 times bigger.
The discovery may help resolve a long-standing mystery about ultra-compact dwarf galaxies, which are densely packed, spherical conglomerations of stars.
Scientists suspect these galaxies are the centers of what were once much larger galaxies that were striped of stars by passing neighbors. After the raid, the dense center cluster and its supermassive black hole were all that remained.
“There are quite a few of these ultra-compact dwarf galaxies and people have debated the nature of these objects for a long time. Are they just really, really massive star clusters -- because that’s really what they look like -- or are they the stripped nuclei of galaxies? This one is the first clear case that it is a striped galaxy nucleus,” University of Michigan astronomer Amy Reines told Discovery News.
The discovery also means that the local universe may be teeming with many more supermassive black holes than previous surveys suggest.
“This gives us a whole new home for black holes that we never knew existed before,” Reines said.
M60-UCD1 showed up on astronomer’s proverbial radar screens by an unusual X-ray emission.
“That could be a sign of a weakly accreting, really massive black hole,” said lead researcher Anil Seth, with the University of Utah. “But it also could be a stellar-mass black hole that’s rapidly accreting, or a neutron star.”
“It was an intriguing possibility,” Seth told Discovery News.
Read more at Discovery News
A team of researchers has delineated the "Venus Zone," the range of distances from a host star where planets are likely to resemble Earth's similarly sized sister world, which has been rendered unlivably hot due to a runaway greenhouse effect.
The new study should help scientists get a better handle on how many of the rocky planets spotted by NASA's prolific Kepler space telescope are truly Earth-like, team members said.
"The Earth is Dr. Jekyll, and Venus is Mr. Hyde, and you can't distinguish between the two based only on size," lead author Stephen Kane, of San Francisco State University, said in a statement. "So the question then is, how do you define those differences, and how many 'Venuses' is Kepler actually finding?"
The results could also lead to a better understanding of Earth's history, Kane added.
"We believe the Earth and Venus had similar starts in terms of their atmospheric evolution," he said. "Something changed at one point, and the obvious difference between the two is proximity to the sun."
Kane and his team defined the Venus Zone based on solar flux — the amount of stellar energy that orbiting planets receive. The outer edge of the zone is the point at which a runaway greenhouse effect would take hold, with a planet's temperature soaring thanks to heat-trapping gases in its atmosphere. The inner boundary, meanwhile, is the distance at which stellar radiation would completely strip away a planet's air.
The thinking is similar to that behind the "habitable zone" — the just-right range of distances from a star at which liquid water, and perhaps life as we know it, may be able to exist.
The dimensions of these astronomical zones vary from star to star, since some stars are hotter than others. In our own solar system, the Venus Zone's outer boundary lies just inside the orbit of Earth, researchers said.
Future space-based instruments — such as NASA's $8.8 billion James Webb Space Telescope, scheduled to launch in 2018 — will be able to analyze some exoplanets' atmospheres, helping scientists refine the Venus Zone concept, researchers said.
"If we find all of these planets in the Venus Zone have a runaway greenhouse-gas effect, then we know that the distance a planet is from its star is a major determining factor. That's helpful to understanding the history between Venus and Earth," Kane said.
Read more at Discovery News
Sep 16, 2014
The squid had been kept in optimum freezing conditions at the Te Papa museum in Wellington ever since it was brought back to New Zealand from the seas off the frozen continent during the southern hemisphere's summer.
The colossal squid is thought to extend up to 4-5 metres (13-16 feet) from tip to tentacle and weigh up to 500 kilograms. Its relation, the giant squid, can grow a lot longer but is much more spindly.
This specimen, like other octopus and squid species, has three hearts -- one to pump blood around the body and two for its gills (lungs) -- and is estimated to be about 3.5 metres in length.
"This one had two perfect eyes," scientist Kat Bolstad from Auckland University of Technology who led the examination told AFP.
"They have very large and very delicate eyes because they live in the deep sea. It's very rare to see an eye in good condition at all."
Measurements revealed the animal's eye was 35 centimetres (14 inches) in diameter, and confirmed that the specimen was a female.
"We were excited to find that out... as it turns out this one is a female, and it has got some eggs," Bolstad told reporters.
"This was by far the most perfect colossal squid that I have seen."
The only other time scientists anywhere have had the chance to examine an intact colossal squid was in 2008, also at Te Papa, the museum said. That specimen was also female.
Bolstad said the latest specimen was so well preserved the scientists were able to examine it with an unusual level of detail, including the lens on the eyes.
"The fact that we have a specimen in good shape, but that we can get so much information from and still have in good shape, is a win-win," Bolstad said.
Read more at Discovery News
The ongoing excavations at the Kasta Hill burial mound in Amphipolis -- about 65 miles (104 kilometers) east of Thessaloniki -- have generated excitement and speculation over what (and whom) archaeologists might find inside.
The latest images, released by the Greek Ministry of Culture yesterday (Sept. 14), show an arched, soil-filled room, with some traces of red paint on the limestone walls. The chamber lies beyond beyond the two female statues known as caryatids that were uncovered last week.
The Kasta Hill tomb is enclosed by an enormous wall whose perimeter measures 1,600 feet (490 meters). In August, archaeologists revealed two broken sphinxes at the entrance to the burial complex. Over the past several weeks, they've been removing soil and walls of heavy sealing stones to probe deeper into the tomb. They've discovered mosaic floors, and last week, the team uncovered the wavy-haired caryatids — statues that take the place of columns or pillars — standing guard at the second doorway.
The archaeologists, led by Katerina Peristeri, have said they believe the tomb dates back to the late fourth century B.C. and has the characteristics of a work by Dinocrates, Alexander the Great's chief architect. But excavators are unlikely to find the body of Alexander the Great himself; historical records indicate he was buried in Alexandria, though his body has never been found.
"This is an ongoing excavation; much more will be discovered as the excavation goes forward," Beth Carney, a history professor at Clemson University, told Live Science in an email. Carney, who is not involved in the excavation, said the tomb seems remarkable for its huge circumference and carved portals, but she isn't sure what evidence the archaeologists have for a late fourth century B.C. date.
The date of the tomb could prove important if archaeologists find bones inside that are tough to identify. Archaeologists have quarreled for decades over the identity of a couple buried in the lavish Macedonian tomb at Vergina in northern Greece, near the site of the early capital of the Kingdom of Macedonia. When Greek archaeologist Manolis Andronikos opened the grave (dubbed Tomb II) at Vergina in 1977, he claimed to have found the resting place of Alexander's father, Philip II, a powerful leader in his own right who paved the way for his son's conquests before he was assassinated in 336 B.C. But others have suggested that the tomb actually belonged to Philip III Arrhidaeus, Alexander's (perhaps mentally disabled) half-brother, who was executed in 317 B.C. after a less successful reign.
Read more at Discovery News
The event wiped out about half of plant species, and fast-growing deciduous trees replaced evergreens, researchers from the University of Arizona report.
"When you look at forests around the world today, you don't see many forests dominated by evergreen flowering plants," said the study's lead author, Benjamin Blonder from the University of Arizona, in a statement. "Instead, they are dominated by deciduous species, plants that lose their leaves at some point during the year."
Blonder and his colleagues studied 1,000 plant leaves fossilized in southern North Dakota, which are stored at the the Denver Museum of Nature and Science.
"There is a spectrum between fast- and slow-growing species," Blonder said. "There is the 'live fast, die young' strategy and there is the 'slow but steady' strategy. You could compare it to financial strategies investing in stocks versus bonds."
Evergreens take more time to build their leaves and last a long time, the researchers reported. Deciduous plants die sooner, but they're able to move more water and acquire carbon faster.
"If you think about a mass extinction caused by catastrophic event such as a meteorite impacting Earth, you might imagine all species are equally likely to die," Blonder said. "Survival of the fittest doesn't apply — the impact is like a reset button. Our study provides evidence of a dramatic shift from slow-growing plants to fast-growing species."
From Discovery News
Schizophrenia is classified as a psychotic disorder, one characterized by an inability to discern what is real and not real, to think clearly, have normal emotional responses, and act normally in social situations. As Elyn Saks told us last year, "it's a waking nightmare, where you have all the bizarre images, the terrible things happening, and the utter terror -- only with a nightmare you open your eyes and it goes away. No such luck with a psychotic episode."
Scientists aren't entirely sure what causes it, nor does it manifest identically in all people who have it (leading to the broader diagnosis of being on the 'schizophrenia spectrum'). But links have been made to genetics, social factors (including early development), and neurobiology. The heritability link looks to be particularly promising, however; about 80 percent of the risk for schizophrenia is genetic. Yet scientists have struggled to identify which genes are responsible for the condition.
But a novel approach to analyzing genetic influences on more than 4,000 people with schizophrenia has finally allowed researchers to identify distinct gene clusters that contribute to eight different classes of schizophrenia.
"Genes don't operate by themselves," noted C. Robert Cloninger, MD, PhD, one of the study's senior investigators in a statement. "They function in concert, much like an orchestra, and to understand how they're working, you have to know not just who the members of the orchestra are but how they interact."
Indeed, complex diseases like schizophrenia may be influenced by hundreds or thousands of genetic variants that interact with one another in complicated and dynamic ways, leading to what scientists call "multifaceted genetic architectures." Now, thanks to the work of investigators at the Washington University School of Medicine in St. Louis, the genetic architecture for schizophrenia is starting to take shape.
For the study, Cloninger and his colleagues matched precise DNA variations in people with and without schizophrenia to symptoms in individual patients. In total, they looked at nearly 700,000 sites within the genome where a single unit of DNA is altered (i.e. a single nucleotide polymorphism, or SNP). Specifically, they analyzed the SNPs of 4,200 people with schizophrenia and 3,800 people without it. This allowed them to learn how individual genetic variations interact with each other to produce the illness.
So, for example, hallucinations and delusions were associated with one set of DNA variations, that carried a 95 percent risk of schizophrenia. Another symptom, disorganized speech and behavior, was found to carry a 100 percent risk with another set of DNA.
"What we've done here, after a decade of frustration in the field of psychiatric genetics, is identify the way genes interact with each other, how the 'orchestra' is either harmonious and leads to health, or disorganized in ways that lead to distinct classes of schizophrenia," Cloninger said.
When it comes to schizophrenia and other complex conditions, individual genes have only a weak and inconsistent association (which is why it's often silly to look for single-gene factors). But groups of interacting gene clusters create an extremely high and consistent risk of illness -- in this case, on the order of 70 percent to 100 percent. It's nearly impossible for people with these precise genetic variations to avoid the condition. In all, the researchers found no less than 42 clusters of genetic variations that significantly increase the risk of schizophrenia.
"In the past, scientists had been looking for associations between individual genes and schizophrenia," explained Dragan Svrakic, PhD, MD, a co-investigator and a professor of psychiatry at Washington University. "When one study would identify an association, no one else could replicate it. What was missing was the idea that these genes don't act independently. They work in concert to disrupt the brain's structure and function, and that results in the illness."
According to Svrakic, the key to the study was in organizing the genetic variations and the patients' symptoms into groups. This allowed them to see that particular clusters of DNA variations acted together to cause specific symptoms. Patients were then divided according to the type and severity of their symptoms. Results showed that those symptom profiles corresponded to eight qualitatively distinct disorders based on underlying genetic conditions.
Read more at Discovery News
Sep 15, 2014
Paleontologists discovered the massive fossil in 2007 during fieldwork in the Rukwa Rift Basin in southwestern Tanzania.
Political instability in certain parts of Africa can prevent dinosaur digs, but fossils in this part of the world are also elusive for geological reasons. As the continents drifted apart, Africa did not move as much as the other continents did, leaving its fossils buried instead of pushed up by plate tectonics, said Patrick O'Connor, a professor of anatomy at Ohio University in Athens, Ohio, and one of the researchers on the new study.
Africa also had fewer ideal areas where sediment could quickly bury a creature and begin the fossilization process. Politics and geology, "those two things together account for why we don't know so much about continental Africa as we do about other parts of the world," O'Connor said.
Joseph Sertich, then a graduate student at Stony Brook University in Long Island, New York, and now a paleontologist at the Denver Museum of Nature & Science, was the first to spot the bones in the Rukwa Rift Basin.
"He scrambled into a gully and found the skeleton coming out the cliff surface," O'Connor said.
A careful excavation by local coal miners and paleontologists in 2007 and 2008 suggests that muddy elements had buried the dinosaur's remains — not once, but twice, O'Connor told Live Science. About 100 million years ago, the dinosaur likely died on a muddy floodplain. Mudstone eventually covered its body, but shortly after, a river running through the plain cut away at the mudstone, exposing part of the skeleton and encasing it in sandstone.
A river still runs near the site, and its drainage through the cliff face had begun to uncover the ancient skeleton, O'Connor said.
The researchers recovered about two dozen fossilized bones, enough to determine that they had a new species on their hands, O'Connor said. An analysis of the bones' shapes and features suggest the dinosaur was a titanosaurian, a member of the giant, long-necked and plant-eating sauropod dinosaurs.
The paleontologists named the dinosaur Rukwatitan bisepultus for the Rukwa Rift Basin and its titanosaurian roots — an allusion to the powerful and mythical Greek Titan deities. In Latin, bisepultus means "twice buried," said Eric Gorscak, the study's lead researcher and a doctoral candidate of biological sciences at Ohio University.
"A lot of what we know about titanosaurian evolution and their biology stems from South America, where there's a lot of specimens," Gorscak said. Titanosaurian remains are found on every continent including Antarctica, but "the early evolutionary history outside of South America is fuzzy."
The new finding helps bridge that gap, said Matthew Lamanna, a curator of vertebrate paleontology at the Carnegie Museum of Natural History in Pittsburgh, who was not involved with the study.
Rukwatitan is important because it's "one of the very few Cretaceous-aged dinosaurs known from Africa south of the Sahara Desert," Lamanna told Live Science in an email. "That part of the world is one of the biggest 'black holes' in our understanding of dinosaurs," he said.
Previously, paleontologists found thetitanosaurian Malawisaurus dixeyi in Malawi, but the Rukwatitan fossils are markedly different in shape and size from that specimen and other titanosaurians found in northern Africa, O'Connor said.
Rukwatitan weighed between 10 and 15 tons — about as much as two elephants but not nearly as much as Dreadnoughtus schrani, another type of titanosaurian, discovered in Argentina, that weighed about 65 tons, Gorscak said. He and his colleagues used a computed tomography (CT) scan to view Rukwatitan's bones and its internal structure. Like other titanosaurians and meat-eating theropods — dinosaurs that may have given flight to birds — Rukwatitan's neck bone was hollow and filled with air.
Read more at Discovery News
The massive beast, Eremotherium eomigrans, along with all of the sloth's giant predecessors, went extinct by about 11,000 years ago.
The new study found that some sloth lineages grew more than 220 pounds (100 kilograms) every million years — one of the fastest body growth rates known in the evolution of mammals. The rapid growth rate indicates that several factors in prehistoric times, such as environmental conditions or competition with other animals, may have favored large sloths, the researchers said in a statement.
Other studies have examined sloth growth rates, but accounted for only living species. The researchers incorporated extinct sloths into the equation for the new study to show that the animals grew at an incredibly fast rate over time.
There are six species of sloths living in South America today, which reach a maximum weight of about 12 lbs. (6 kg). However, the fossil record shows a richer diversity, with more than 50 known species that lived between about 2.6 million and 11,700 years ago. In all, the researchers looked at 57 species of sloths that are living or from the fossil record, and examined the average changes in body mass throughout their evolution, the study reported.
"Today's sloths are really the black sheep of the sloth family," study co-author Anjali Goswami, of the University College London earth sciences department, said in a statement. "If we ignore the fossil record and limit our studies to living sloths, as previous studies have done, there's a good chance that we'll miss out on the real story and maybe underestimate the extraordinarily complex evolution that produced the species that inhabit our world."
Nowadays, sloths are vegetarians that live in trees and typically weigh between 8 and 12 pounds (3.5 and 5.5 kg), the researchers said. In contrast, extinct sloths lived in a range of environments, and included ground-, tree- and water-dwelling sloths. Fossilized footprints suggest that some of these ancient sloths walked on their hind legs, and may have also eaten both plants and animals.
Read more at Discovery News
At that time, the Nile wasn't surrounded by desert; rather, the warmer, wetter landscape resembled the current scenery of sub-Saharan East Africa.
Today, Egypt's elephants and giraffes are extinct. So are its cheetahs and aurochs and wildebeests. But animal bones and images of animals on ancient artifacts reveal what creatures once roamed the region. A team of researchers looked at Egypt's rich archaeological record and found that most mammal extinctions over the last six millennia were linked to periods of big change in terms of climate and human civilization.
Justin Yeakel -- a researcher out of the University of California, Santa Cruz, who is now a postdoctoral fellow at the Santa Fe Institute in New Mexico -- said the work was first inspired by a trip with a colleague to see a traveling exhibit on King Tutankhamun while it was in San Francisco a few years ago.
"We were just amazed at the diversity of animals in the artifacts," Yeakel told Live Science. "It got us thinking about how we could use representations of animals in the historical record to understand how animal communities have changed."
Egypt turned out to be a good area for a case study, because the area has been occupied continuously for thousands of years and has an extensive archaeological record. There are rock art drawings of hippopotamuses and rhinoceroses from the early Holocene. The tombs of Egyptian pharaohs are decorated with hunting scenes that show which creatures would have been prized prey. Import records of cheetahs and lions reveal when certain animals might have been considered exotic after disappearing locally.
The researchers found that Egypt was home to 37 large-bodied mammals (those over 8.8 lbs., or 4 kilograms) during the Late Pleistocene and early Holocene. Today, just eight of those creatures remain: the golden jackal, the ibex, the Barbary goat, the Egyptian fox, the Dorcas gazelle, the wild ass, the striped hyena and the slender-horned gazelle, which is on the verge of extinction.
"Our simplest observation was that the community changed in a very nonrandom way," Yeakel said.
The stability of the ecosystem tended to unravel during periods of major climate change and socio-political turnover, the scientists found. When the so-called African Humid Period ended about 5,000 years ago, Egypt's landscape switched to a drier, desert-like climate; around the same time, humans started farming and ancient Egypt's Dynastic Period began. Another aridification period occurred about 4,170 years ago and has been linked to the collapse of Egypt's Old Kingdom, the period that saw the first pyramids. A third drying period has been linked to the fall of the New Kingdom in Egypt about 3,000 years ago.
Yeakel said he and his fellow researchers can't really tease apart the possible causes that led to these ecological changes. But the scientists have identified the potential drivers. During the first big change after the African Humid Period, for example, human populations grew and overhunting might have driven the decline of large herbivores -- such as elephants, giraffes and native camels -- which then indirectly affected the populations of the predators that ate the herbivores. Agriculture was also on the rise during this period. Most of the region's nutrients were concentrated in the Nile floodplain, and competition with farmers might have also hurt herbivore populations. A third possible driver could have been the climate; the drier environment might have limited the availability of plants at the bottom of the food chain.
Read more at Discovery News
This civilization, which pre-dates the Aztecs, remains a mystery in many ways. But new research has found they brewed a tequila-like drink called pulque as a source of food and nutrition, not just to forget their woes.
Pulque is a milky-white liquor made from the maguey plant -- a relative of the agave used in tequila -- and is still popular among local residents. Traces of pulque have been found on pottery shards dating at Teotihuacan dating back to 150 B.C., according to a new study published today in Proceedings of the National Academy of Sciences.
Pulque was not just reserved for the upper classes, according to Marisol Correa-Ascencio, a doctoral student in chemistry at the University of Bristol (UK) and first author on the paper.
"The beverage was consumed by greater part of the population," Correa-Ascencio said. "It could have helped to compliment the diet of the people."
While ancient Egyptian and Mesopotamian cultures brewed beer and wine before the rise of the Teotihuacan culture, this is the earliest finding of an alcoholic beverage in Mesoamerica, Correa-Ascencio said.
Her colleagues used a new approach to identifying chemical residue on the pottery using a lipid biomarker, or a tiny fat molecule that had bonded with the ceramic molecules of the vase-like amphoras that held the pulque and were sealed with pine resin.
"The principle is that when you process food like cooking or storing, the lipids are absorbed into the ceramic matrix and get encapsulated," Correa-Ascensio said. "We take a potsherd, clean it, crush it and then perform lipid extraction."
The researcher said this is the first time this method has been used to identify an ancient alcoholic beverage. Pulque was widely used by the Aztecs at the time of the Spanish conquest in 1521, and remains in use today.
One expert on the Teotihuacan people says the method could be used to research the history of other cultures use of alcohol.
Read more at Discovery News
Archaeologists on the Danish island of Zealand recently discovered a Viking fortress that likely dates back to the 10th century A.D. It's the first time in 60 years that such a fortress has been unearthed in Denmark, the researchers said.
"The Vikings have a reputation as [fierce Norse warriors] and pirates. It comes as a surprise to many that they were also capable of building magnificent fortresses," Søren Sindbæk, a professor of medieval archeology at Aarhus University in Denmark, said in a statement. The discovery of the new fortress provides an opportunity for archaeologists to gain even more knowledge about Viking wars and conflicts, Sindbæk added.
Prior to this latest discovery, three other Viking fortresses were discovered in Denmark. These structures, named Fyrkat, Aggersborg and Trelleborg, are known collectively as the "Trelleborg" fortresses.
"We recognize the 'Trelleborg' fortresses by the precise circular shape of the ramparts and by the four massive gates that are directed at the four corners of the compass," said Nanna Holm, curator of the Danish Castle Centre in Denmark, who helped identify the site of the newly unearthed fortress. "Our investigations show that the new fortress was perfectly circular and had sturdy timber along the front. We have so far examined two gates, and they agree exactly with the 'Trelleborg' plan."
The fortress, located south of the capital city of Copenhagen, is huge, Holm said. It spans nearly 476 feet (145 meters) across, longer than 1.5 football fields.
Archaeologists long suspected that a fourth Trelleborg fortress might exist on the island of Zealand, according to Sindbæk, who has studied these structures for years. And the site of Vallø, now part of the Zealand Region on the east coast of Zealand, is an ideal place for the Vikings to have built such a structure, Sindbæk said.
During the 10th century, Vallø marked the spot where two main roads met, Sindbæk said. It also overlooked the Køge river valley, which at that time was a navigable fjord and one of the best natural harbors on the island, Sindbæk added.
Suspecting a fortress might be buried beneath Vallø, the team of archaeologists used advanced laser and magnetic tools to determine the structure's exact location. The team included Helen Goodchild from the University of York, in the United Kingdom.
"By measuring small variation in the Earth's magnetism, we can identify old pits or features without destroying anything," Sindbæk said. "In this way, we achieved an amazingly detailed 'ghost image' of the fortress in a few days. Then we knew exactly where we had to put in excavation trenches to get as much information as possible about the mysterious fortress."
Read more at Discovery News
Sep 14, 2014
To reconstruct leopard diets, scientists had to take a close look at leopard poop. A team led by researchers with the Wildlife Conservation Society scooped up 85 leopard fecal samples as they scoured footpaths, dried-up streams and fields in a rural section of western Maharashtra (the same state where Mumbai is located). Back in a lab, the researchers looked for signs of claws, hoofs and hair and other indigestible parts of unlucky prey in the scat.
The researchers found that domestic dogs were by far the most common prey, making up 39 percent of the leopards' diet (in terms of biomass). The remains of domestic cats were found in 15 percent of poop samples and accounted for 12 percent of the mass of leopards' meals.
By comparison, livestock were a relatively small portion of the leopard diet. Domestic goats, for example, accounted for just 11 percent of the mass of the big cats' meals, even though they were seven times more abundant than dogs in the study area.
All told, 87 percent of the leopards' diet was made up of domestic animals, including both livestock and pets; this suggests the leopards, though considered wild, are completely dependent on human-related sources of food. The small portion of the wild animals in the leopards' diet consisted of mostly rodents, as well as civets, monkeys, mongooses and birds.
The study illustrates just how big of an impact people have on the lifestyle of leopards that live in human-dominated landscapes. The largely agricultural study area around the town of Akole did not contain any natural patches of forest, and the nearest protected area was the Kalsubai Harishchandragad Wildlife Sanctuary, 11 miles (18 kilometers) to the west.
The researchers speculated that domestic animals make easier prey, because they lack anti-predatory behavior, unlike their wild counterparts. And free-roaming dogs might be particularly easy targets, because they likely are not as heavily guarded as economically valuable livestock.
Read more at Discovery News
A 6.0-magnitude earthquake shook sections of Alaska and Canada's Yukon Territory on July 17. The quake struck Seward Glacier, which is located 62 miles (100 kilometers) from the Alaskan city of Yakutat, reported the Alaska Earthquake Information Center.
NASA scientists based in Fairbanks, Alaska, flew near Seward Glacier one day before the quake, on July 16, and observed that an earlier landslide had strewn rocks and other debris across the icy slopes. Four days after the earthquake, on July 21, the scientists revisited the site and discovered that a quake-induced avalanche had blanketed the mountainside in snow, covering much of the previous landslide's rocky trail.
"It's obvious that many big debris and snow slides happened in this short time window," NASA glaciologist Kelly Brunt said in a statement. "This is a super steep area, so you get a lot of activity here. The bulk of the activity in this case is probably associated with the July 17 quake."
Brunt and her colleagues snapped photos of the earthquake's aftermath using a digital camera mounted inside the nose cone of NASA's high-altitude ER-2 aircraft. The researchers flew within 1.2 miles (2 km) of the earthquake's epicenter.
The scientists were already scheduled to conduct flights over Alaska, near Seward Glacier, to test an instrument called the Multiple Altimeter Beam Experimental Lidar (MABEL), which is designed to detect changes in Earth's landscape — particularly Arctic sea ice — using lasers and photon detectors.
Read more at Discovery News