May 31, 2014

3-D bioprinting builds a better blood vessel

The tangled highway of blood vessels that twists and turns inside our bodies, delivering essential nutrients and disposing of hazardous waste to keep our organs working properly has been a conundrum for scientists trying to make artificial vessels from scratch. Now a team from Brigham and Women's Hospital (BWH) has made headway in fabricating blood vessels using a three-dimensional (3D) bioprinting technique.

The study is published online this month in Lab on a Chip.

"Engineers have made incredible strides in making complex artificial tissues such as those of the heart, liver and lungs," said senior study author, Ali Khademhosseini, PhD, biomedical engineer, and director of the BWH Biomaterials Innovation Research Center. "However, creating artificial blood vessels remains a critical challenge in tissue engineering. We've attempted to address this challenge by offering a unique strategy for vascularization of hydrogel constructs that combine advances in 3D bioprinting technology and biomaterials."

The researchers first used a 3D bioprinter to make an agarose (naturally derived sugar-based molecule) fiber template to serve as the mold for the blood vessels. They then covered the mold with a gelatin-like substance called hydrogel, forming a cast over the mold which was then reinforced via photocrosslinks.

"Our approach involves the printing of agarose fibers that become the blood vessel channels. But what is unique about our approach is that the fiber templates we printed are strong enough that we can physically remove them to make the channels," said Khademhosseini. "This prevents having to dissolve these template layers, which may not be so good for the cells that are entrapped in the surrounding gel."

Khademhosseini and his team were able to construct microchannel networks exhibiting various architectural features. They were also able to successfully embed these functional and perfusable microchannels inside a wide range of commonly used hydrogels, such as methacrylated gelatin or poly(ethylene glycol)-based hydrogels at different concentrations.

Read more at Science Daily

Australia's deadly eruptions were reason for the first mass extinction

A Curtin University researcher has shown that ancient volcanic eruptions in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life.

Published in the journal Geology, Associate Professor Fred Jourdan from Curtin's Department of Applied Geology, along with colleagues from several Australian and international institutions, used radioactive dating techniques to precisely measure the age of the eruptions of the Kalkarindji volcanic province -- where lavas covered an area of more than 2 million square kilometres in the Northern Territory and Western Australia.

Dr Jourdan and his team were able to prove the volcanic province occurred at the same time as the Early-Middle Cambrian extinction from 510-511 million years ago -- the first extinction to wipe out complex multicellular life.

"It has been well-documented that this extinction, which eradicated 50 per cent of species, was related to climatic changes and depletion of oxygen in the oceans, but the exact mechanism causing these changes was not known, until now," Dr Jourdan said.

"Not only were we able to demonstrate that the Kalkarindji volcanic province was emplaced at the exact same time as the Cambrian extinction, but were also able to measure a depletion of sulphur dioxide from the province's volcanic rocks -- which indicates sulphur was released into the atmosphere during the eruptions.

"As a modern comparison, when the small volcano Pinatubo erupted in 1991, the resulting discharge of sulphur dioxide decreased the average global temperatures by a few tenths of a degree for a few years following the eruption.

"If relatively small eruptions like Pinatubo can affect the climate just imagine what a volcanic province with an area equivalent to the size of the state of Western Australia can do."

The team then compared the Kalkarindji volcanic province with other volcanic provinces and showed the most likely process for all the mass extinctions was a rapid oscillation of the climate triggered by volcanic eruptions emitting sulphur dioxide, along with greenhouse gases methane and carbon dioxide.

"We calculated a near perfect chronological correlation between large volcanic province eruptions, climate shifts and mass extinctions over the history of life during the last 550 million years, with only one chance over 20 billion that this correlation is just a coincidence," Dr Jourdan said.

Read more at Science Daily

May 30, 2014

How Twisted Was Richard III's Spine? New Models Reveal

Shakespeare called him a hunchback, but a new three-dimensional model of King Richard III's spiraling spine shows his true disability: adolescent idiopathic scoliosis.

Richard III, who ruled England from 1483 to 1485, died in the Battle of Bosworth in 1485. His body was buried in a hastily dug grave in Leicester, where it was then lost to time. In 2012, archaeologists rediscovered the bones under a city council parking lot, and exhumed them for study.

The curve in Richard's spine was immediately obvious, confirming an anatomical anomaly that had long been controversial. No paintings made during the king's lifetime survive, according to the Richard III Society (though some exist from soon after his death that were likely copied from originals, and modern researchers have reconstructed the king's face).

The popular image of Richard III came from Shakespeare, who describe the king as a "poisonous bunch-backed toad" in his 1593 play. Shakespeare's Richard III had a hunchback and a withered arm, and modern historians were uncertain whether the depiction held any truth or was simply designed to please the political enemies of the king's Plantagenet family line.

Medical history

In 1490, just five years after Richard's death in battle, however, medieval historian John Rous described the king as a small man with "unequal shoulders, the right higher and the left lower." This description is consistent with scoliosis, a condition in which the spine curves sideways.

Richard III's rediscovered skeleton revealed that the king did, in fact, have scoliosis. Now, researchers led by University of Leicester bioarchaeologist Jo Appleby reveals the details of his condition.

Appleby and her colleagues conducted computed tomography scans of the king's individual vertebrae. These CT scans use X-rays to image the inside of the bone, creating virtual slices that can be explored digitally. Using the scans, the researchers then created polymer copies of each vertebra, piecing them together into a 3D model of Richard III's spine.

Model ruler

The scans and model showed that Richard III had a right-sided, spiral-shaped curve that peaked at thoracic vertebrae 8 and 9, approximately at his mid-back. The curve was well-balanced, meaning that Richard III's spine got back in line by the time it hit his pelvis. As a result, his hips were even, the researchers report today (May 29) in the journal The Lancet. Richard III would not have limped or had trouble breathing due to his condition, which are common side effects of severe scoliosis.

"Obviously, the skeleton was flattened out when it was in the ground," Appleby said in a statement. "We had a good idea of the sideways aspect of the curve, but we didn't know the precise nature of the spiral aspect of the condition."

Scoliosis can be caused by muscular imbalances that pull the spine out of alignment, but the rest of Richard III's skeleton showed no evidence of such problems, Appleby and her colleagues found. Nor were there any malformed hemivertebrae, which are wedge-shaped vertebrae that can cause the spine to twist and turn.

Instead, the researchers concluded, Richard III likely had adolescent-onset idiopathic scoliosis. Idiopathic means the cause is unknown, which is the case in the majority of people with scoliosis. The abnormal curve probably appeared in Richard after age 10.

The curve itself had a spiral appearance, and an angle that would be considered large today. Doctors use a measurement called the Cobb angle to gauge spine deformity. On an X-ray, they draw a line outward from the top of the highest vertebra on the curve and then do the same for the bottom of the lowest vertebra. They then measure the angle where the two lines meet. Richard III's Cobb angle was between 70 degrees and 90 degrees in life, the researchers determined.

Without scoliosis, Richard III would have stood about 5 feet, 8 inches (1.7 meters), average for a medieval European man. The curvature would have taken a few inches off his height, and it would have caused the shoulder imbalance that Rous described. Nevertheless, it would not have kept Richard III from being an active individual, Appleby said.

Read more at Discovery News

Unique Silk Cloth Found in Emperor Henry VII's Coffin

A unique silk cloth has been found in the tomb of German king and Holy Roman emperor Henry VII of Luxembourg (1275-1313), among bones and what remains of his boiled head, Italian researchers announced this week.

Resting in Pisa Cathedral, the remains of Henry VII were exhumed last fall with the aim of getting more insights into the emperor’s physical features and cause of death.

The research is still ongoing, but the opening of the sarcophagus has already revealed a medieval treasure trove.

"Along with the emperor's mortal remains, the coffin contained a crown, a scepter and an orb, all made in gilded silver. But the most unexpected find was a large, magnificent silk cloth," Moira Brunori, at the Center for Textile Restoration in Pisa, told Discovery News. "It's extremely well preserved." Brunori said.

As the researchers opened the coffin for the third time since Henry VII's death in 1313 -- previous investigations were carried in 1727 and in 1921 -- they found the emperor's bones wrapped in the silk cloth. The crown, scepter and orb were laid on top of the cloth.

The three objects were commonly associated with the emperor. Indeed a set of contemporary miniatures often show Henry VII wearing them during his journey through Italy.

Celebrated as the "alto Arrigo" (high Henry) in Dante's Divine Comedy, Henry is best remembered for his struggle to reestablish imperial control over the city-states of 14th-­century Italy.

He was crowned King of Germany in 1308 and two years later he descended into Italy with the aim of pacifying destructive disputes between Guelf (pro-papal) and Ghibelline (pro-imperial) factions. His goal was to be crowned emperor and restore the glory of the Holy Roman Empire.

After meeting strong opposition among anti-imperialist Guelf lords, Henry entered Rome by force, and was indeed crowned Holy Roman Emperor on June 29, 1312.

"He who came to reform Italy before she was ready for it," as Dante described Henry VII, died just a year after his coronation, having failed to defeat opposition by a secular Avignon papacy, city-states and lay kingdoms.

Henry died prematurely at Buonconvento, near Siena, on Aug. 24, 1313. Rumors of him being poisoned began to spread.

The emperor's body was hastily buried; two years later he was reburied in the Cathedral of Pisa.

"Not having enough time to treat the corpse for transportation, the emperor's followers burned his body, detached the head and boiled it. His bones were kept in wine to better preserve them," Brunori said.

Indeed researchers found in the coffin ashes and bones showing signs of burning.

Anthropological examination has revealed the skeleton belonged to a 40-year-old male who was 5 feet, 5 inches tall -- and who was used to kneeling in prayer.

Analysis has so far revealed a high concentration of arsenic in the bones, which could support the poisoning theory, although many drugs at that time were arsenic based.

Not much evidence has emerged about Henry's demise by malaria, which has long been considered by many scholars a likely cause of death.

As for the silk cloth, it is unclear how it ended up in the coffin.

"In 1921, it was described as a piece of cloth with little value," Brunori said. "Instead it's a unique example of the noble production of silk textiles dating back to the beginning of the 14th century."

More than 10 feet long and 4 feet wide, the exquisitely woven cloth features horizontal bands of around 4 inches showing alternating colors, a reddish nut-brown (originally red) and blue.

"The blue bands are embroidered in gold and silver with pairs of lions facing each other, while an elaborated monochromatic tone-on-tone decoration, currently indecipherable, is visible on the reddish bands," Brunori said.

A crimson strip edged with yellow, placed at the top of the piece of fabric, bears traces of an inscription. Other unique features are the finished edge along the length of the fabric -- to keep it from unraveling -- and the checked bands at the shorter ends marking the beginning and end of the piece.

"The chequered starting and finishing borders are typical of this period," leading textile expert Lisa Monnas told Discovery News.

"For textile historians, it is exciting to see a complete loom width of silk fabric from this date, and, if it has both starting and finishing borders, a complete piece. It would be even more exciting if the inscription could be deciphered," she added.

According to Brunori, the lions, the most characteristic emblem of sovereignty, as well as other decorations symbolizing power, indicate a clear link to the emperor.

"What makes this cloth unique is its size, the very high level of craftsmanship and its amazing preservation," Brunori said.

According to Gale Owen-Crocker, professor of Anglo-Saxon Culture at the University of Manchester and an expert on medieval clothing and textiles, such silks were treasured possessions of the rich and royal.

"Expensive silks have been found in medieval royal and ecclesiastical graves. St. Cuthbert, the seventh-century English ascetic and bishop had several precious silk cloths added to his tomb over a period of centuries," Owen-Crocker told Discovery News.

Read more at Discovery News

Ancient Rock Hints at Early Continent Formation

How did Earth's continents first form? A University of Alberta geochemistry PhD student studied a 4-billion-year-old rock and concluded: Look at modern-day Iceland.

The student, Jesse Reimink, collected ancient rock samples from the Acasta Gneiss complex in Canada's Northwest Territories, which contains some of the planet's oldest rocks.

Because they're so old and have undergone so many changes, many of the Acasta Gneiss rocks don't lend themselves to precise geochemical analysis. But some of the ones Reimink collected were preserved well enough to reveal what Reimink called, in a University of Alberta (U of A) article, "crust-forming processes that are very similar to those occurring in present-day Iceland."

Today it's accepted that plate tectonics -- in which pieces of the Earth's crust shift beneath each other into the Earth's mantle and cause magma to rise to the surface -- are responsible for the buildup of continents.

But, Reimink told the U of A, it's not as clear whether plate tectonics existed a couple of billion years ago. One theory holds that the land masses formed in the ocean as liquid magma rose from Earth's mantle and then, over much time, cooled and became a solid crust.

Iceland's crust built up when magma from the mantle rose to shallow waters and incorporated volcanic rocks already in place. Reimink says this makes today's Iceland a good proxy for how continental crust formed in the early life of Earth.

Read more at Discovery News

The Parasitic Worm That Turns Crickets Into Suicidal Maniacs

A mass of parasitic horsehair worms emerge from their host, then immediately mate. “Oh, come on, guys,” says the cricket. “Get a room—one that isn’t my abdomen.
In 333 B.C., Alexander the Great marched his army into the city of Gordion, where there was a massive knot in desperate need of untying. Legend held that the hero who could undo this exceedingly intricate Gordian Knot, as it was not-so-creatively called, would rule Asia. Alexander, unable to unravel the knot, drew his sword and sliced right through it, then, apparently with the blessing of the eviscerated loops, went on to conquer Asia minor.

The tall tale gives us the expression “to cut the Gordian Knot,” meaning to solve a seemingly insurmountable problem by over-the-top means. It also lends its name to one of the animal kingdom’s most clever parasites, the Gordian worm, which has solved the often insurmountable problem of survival with means that are horrifyingly over-the-top.

More commonly known as the horsehair worms, because folks with a limited understanding of reality once thought they were horsehairs that animated upon hitting water, the 350 or so known species invade insects like the luckless cricket above. After developing for several months, the worms mind-control their hosts to make a kamikaze dive into water, then escape through holes bored in the insect’s exoskeleton. The parasites end up in a tangled knot that can be as heavy as the tattered—and oftentimes very much alive—host they leave behind.

All across America in rivers or streams, horsehair worm eggs hatch and settle lazily to the bottom as larvae (we’ll be talking specifically about the species Paragordius varius and its parasitism of crickets). Unable to swim up the water column, the larva simply wait to be eaten by the larvae of other insects like midges, mayflies, and mosquitoes. When these insects metamorphose and emerge from the water, they live out their aerial lives with the larva in tow, then inevitably croak and get snatched up by a cricket, according to parasitologist Ben Hanelt of the University of New Mexico.

Once the worm larvae find themselves in the insect, “they will penetrate through the gut of the cricket and get into the body cavity, where they then grow from a tiny, tiny larva to something that’s now on the average of a foot long,” he said. (There’s a 6-foot species, by the way, that parasitizes an as-yet-unknown insect, probably a giant and perpetually nervous cockroach.)

Can you find the horsehair worms in this photo? It’s like Where’s Waldo, only horsehair worms despise horizontal stripes.
Really, the horsehair worm is nothing more than a giant gonad wrapped in a thin sheath of muscles, and I say that with all due reverence. Curiously, they don’t even have a mouth to eat with or chew their way through the cricket, so Hanelt remains unsure how they bore into the body cavity, and then through the exoskeleton to escape.

And there’s no digestive system as we would recognize it, because like the tapeworms that take up residence in our guts, they’re living in a veritable sea of food. “The way that these guys actually get their nutrients is right through the cuticle,” said Hanelt. “Right through the skin of the worm is where the fat and the sugar is actually absorbed straight from the body fluids of the host.”

Robbed Zombies

Now, it’s nearly impossible to identify an infected cricket, for this is no clumsy zombie of popular culture. Outwardly, the cricket behaves quite normally, save for a brilliant little trick the worm plays: It manipulates them to shut the hell up with the chirping. Chirping is, after all, energetically expensive, not to mention a real fine way to get yourself noticed and eaten, a rather anticlimactic end to the worm’s grand scheme.

When the worm is ready to leave the cricket, though, you’ll know it. Typically crickets give running water a wide berth, instead getting their hydration from food and the occasional dew drop. According to Hanelt, you can take a non-infected specimen and drop it near running water and it’ll leg it right out of there, every time. The dangers of hungry fish and drowning are simply too great.

 But a cricket infected with a horsehair worm swears, quite wrongly, that it’s a great swimmer. At the behest of the worm it seeks out bodies of water with its antennae, which pick up the slightest changes in humidity. Then, seemingly against its better judgment, the host proceeds to perform a sicknasty cannonball: “If you take a cricket that actually has a worm in it,” said Hanelt, “and put it next to the water, it will always, in every case, jump immediately in.”

After admiring the cannonball, the worm, monitoring the world through a porthole it bored in the cricket, makes its move, squirming out of its host as soon as it hits the water. In nature, it’s typically one worm per cricket, though every now and then two or three will emerge. In Hanelt’s lab, however, his record is an astonishing 32 worms erupting from one unfortunate host (that GIF at top, which I ain’t even about to apologize for, was half that many worms).

The parasite, now free, will swim around in search of a mate. When they pair up, the male aligns his cloaca with the female and passes his sperm. Having served his sole earthly purpose, he will die. The female goes on to lay as many as 15 million eggs, which she pastes underwater on a stick or stone. When she’s done, she too will die, emptied of eggs and totally flattened out like a straw wrapper that’s lost its straw. Two weeks later, her eggs hatch into the larvae that settle once more onto the river bottom, beginning the process anew.

It’s a remarkable tale of an organism adapting over evolutionary time to manipulate another and use it as a private escort. But how on Earth can the worm hijack a cricket’s brain? And why would this evolve in the first place?

After laying her eggs, the female horsehair worm perishes. Which is just as well, since she releases up to 15 million of the things. Ain’t nobody got time for that amount of parenting.
 “First of all,” said Hanelt, “the worm appears to be producing large amounts of neurotransmitters,” chemicals that allow the transmission of signals between neurons. “And the neurotransmitters that it’s producing are thought to make the cricket basically act in ways that normally the cricket wouldn’t act. And exactly which neurotransmitters these are and how they’re affecting the crickets, that we don’t know.” Secondly, it appears the worm triggers the cricket to boost production of neurotransmitters. But there is still much, much to be learned, just as there is with other highly sophisticated mind-controllers like wasps that enslave cockroaches and fungi that zombify ants.

As for why the worms would have needed to evolve such tactics, we have only theories. For Hanelt’s money, it’s a matter of opportunism. In the high deserts of New Mexico, he finds horsehair worms aplenty. Wandering through an extremely dry forest, he’ll come across a dinner-plate-sized puddle, and sure enough, there they squirm. “When I look around, I see very few resources,” he said, “flowering plants, grasses, etc. So, if I was a worm, the best way to make a living out here is to get into a very nutritious insect host, which is filled with fat. This represents the easy life.”

Read more at Wired Science

May 29, 2014

Spider Masquerades as Bird Poo to Avoid Being Eaten

One of the best ways to avoid being bothered is to masquerade as something unsavory, reports a new study identifying a spider whose web and body resemble bird droppings.

The orb-web Cyclosa ginnaga adds to the growing list of spiders that are nearly indistinguishable from avian excrement.

In this case, the spider sells the look via additions, otherwise known as "decorations," to its web, which may include carcasses, egg sacs, plant detritus or silk.

Researchers Min-Hui Liu and colleagues explained: "We found that: (1) the presence of the spider's decorations rendered its body indistinguishable from bird droppings in the eyes of its predators and (2) concealing C. ginnaga's web decorations resulted in an increase in predatory attack probability. Accordingly, we concluded that the body and web decorations of C. ginnaga form a bird dropping masquerade to avoid predators."

Liu is a researcher at National Chung-Hsin University and the Taiwan Endemic Species Research Institute.

For the study, published in the latest issue of Scientific Reports, Liu and the other scientists compared the spider's body and its web to bird poop, in terms of how they reflect light and otherwise appear in a natural setting.

Since those values were so similar, the scientists suspected that wasp predators could not distinguish between these very different items. They tested the theory by monitoring what happened when they blackened, with carbon powder, some of the spider bodies, thus ridding the spiders of their disguise.

Sure enough, the blackened spiders were quickly attacked and eaten by the wasps. The other spiders, retaining their poop look, were usually ignored.

Masquerading as bird poo could be much more common than previously thought among spiders. The spider Celaenia excavate's common name is "the bird-dropping spider." Species from the genus Mastophora, such as the bolas spider, also resemble bird feces.

In addition to keeping predators at bay, the disguise may help the spiders to fool their own prey. The bird-dropping spider, for example, stays motionless on its web during the day to fool passers by.

At night, the spider engages in another form of mimicry. It releases a moth female sex pheromone that attracts male moths. Once the moths come close, the spider suddenly jumps into action, capturing the amorous moth victim with its powerful front legs.

Read more at Discovery News

'Fish Lizard' Graveyard Discovered Under Melting Glacier

Dozens of nearly complete skeletons of prehistoric marine reptiles have been uncovered near a melting glacier in southern Chile.

Scientists found 46 specimens from four different species of extinct ichthyosaurs. These creatures, whose Greek name means "fish lizards," were a group of large, fast-swimming marine reptiles that lived during the Mesozoic Era, about 245 million to 90 million years ago.

The newly discovered skeletons are from both embryos and adults. The creatures, likely killed during a series of catastrophic mudslides, were preserved in deep-sea sediments that were later exposed by the melting glacier, the researchers said in the study, published May 22 in the journal Geological Society of America Bulletin.

Ichthyosaurs had torpedo-shaped bodies with vertical flippers, and long snouts with teeth.

"They look a lot like dolphins today," said Wolfgang Stinnesbeck, a paleontologist at the University of Heidelberg in Germany and the leader of the study.

Stinnesbeck and his team found the Early Cretaceous (150 million to 100 million years old) specimens near the Tyndall Glacier in the Torres del Paine National Park in Chile. As the glacier melted, the rock containing the fossils became exposed, Stinnesbeck told Live Science.

Very few of the ancient reptiles have been found in South America before; only a few remnants of rib cages and vertebrae had been found.

The largest ichthyosaur skeleton unearthed in Chile measures more than 16 feet (5 meters) long. The skeletons were extremely well preserved — some even retained soft tissues. The researchers also found fossil embryos inside a female specimen. They assigned the fossils to the family Ophthalmosauridae.

These "fish lizards" probably hunted in an underwater canyon near the coastline, pursuing a diet of squidlike animals and fish, the researchers said. Occasionally, there would have been mudflows that cascaded into the water like an avalanche, and the researchers think these mudflows killed the ichthyosaurs. The animals likely became disoriented and drowned, getting sucked into the deep sea, where their bodies were entombed in the sediment, the researchers said.

Read more at Discovery News

Measles Infections in U.S. Reach 20-Year High

The United States hasn't seen so many measles cases since 1994, with 288 cases of the highly contagious respiratory disease reported to the Centers for Disease Control and Prevention so far this year — about double the number seen last year.

“The current increase in measles cases is being driven by unvaccinated people, primarily U.S. residents, who got measles in other countries, brought the virus back to the United States and spread to others in communities where many people are not vaccinated,” said Dr. Anne Schuchat, assistant surgeon general and director of CDC's National Center for Immunizations and Respiratory Diseases, in a press release.

The vast majority (97 percent) of the U.S. infections were imported from at least 18 countries, including the Philippines, where there are about 26,014 suspected cases, over 6,000 confirmed cases, and at least 41 deaths.

Among the infected U.S. residents who were not vaccinated (90 percent), most (85 percent) chose not to vaccinate for religious, philosophical or personal reasons.

The U.S. cases tend to be clustered. In Ohio, for example, unvaccinated Amish missionaries who traveled to the Philippines may have spread the disease to at least 138 people.

“We believe people are still getting exposed,” Melanie Amado, public information officer for the Ohio Department of Health told CNN earlier this week, because the incubation period for measles is up to 21 days.

Other affected areas include California with 60 cases and New York City with 26 cases; 17 states overall have reported measles in patients ranging from babies to 65-year-olds.

Read more at Discovery News

Lyme Disease Bacteria Older than the Human Race

The bacteria that causes Lyme disease has been around for a super-whopping long time, according to evidence pried from ticks trapped in amber some 15 to 20 million years ago.

Researchers from Oregon State University (OSU) studied four ticks found in the Dominican Republic, and the sap-trapped critters revealed a large grouping of cells that bear a close resemblance to Borrelia, a type of bacteria that to this day causes Lyme disease.

The ticks represent the oldest known fossil evidence of Borrelia, and they suggest the startling notion that tick-borne bacteria has likely been delivering Lyme disease to humans for as long as there have been humans.

Soft-bodied bacteria aren't often preserved in the fossil record, but amber, which starts out as tree sap, makes a great preservation medium, as it slowly bides its time and becomes a mineral.

Lyme disease itself was not even identified until 1975. The disease -- which hampers the joints, heart and central nervous system -- can be cured with antibiotics if it's caught early, but it's often misdiagnosed.

The tick-borne disease has been on the rise, thanks to growing deer populations in many areas. Lyme disease cases in Nova Scotia, for example, nearly tripled in 2013 from the prior year.

"In the United States, Europe and Asia, ticks are a more important insect vector of disease than mosquitoes," noted George Poinar, Jr., professor emeritus in the Department of Integrative Biology of the OSU College of Science, in a press release.

"(Ticks) can carry bacteria that cause a wide range of diseases, affect many different animal species, and often are not even understood or recognized by doctors," Poinar said. "It's likely that many ailments in human history for which doctors had no explanation have been caused by tick-borne disease."

Read more at Discovery News

What Is 'Manhattanhenge?'

This Thursday marks a biannual solar event called Manhattanhenge, where the rising or setting sun aligns with the east-west grid of Manhattan streets. Astrophysicist Neil deGrasse Tyson coined the term back in 2002, inspired by the famous Stonehenge site in the United Kingdom, where the sun sets in alignment with the stones every summer solstice.

Technically, “Manhattanhenge” occurs around the summer solstice, not on the solstice itself. That’s because of the orientation of Manhattan’s famous grid pattern — established by the the Commissioners’ Plan of 1811 — is not perfectly aligned with the geographic north-south line; it’s rotated 29 degrees east, shifting the dates of alignment. If that alignment had been perfect, Manhattanhenge would have occurred on the equinoxes every year: the first day of spring and autumn, respectively.

(Historical side note: The goal of the 1811 plan was “a free and abundant circulation of air” to stave off disease. The right angles were also favored because “straight-sided and right-angled houses are the most cheap to build.” The rigid Manhattan grid has been much-maligned over the last 200 years, but recently has come back into favor with city planners.)

This kind of alignment is not unique to Manhattan; any city with a uniform street grid will have dates where the sun aligns with those streets, including Chicago, Toronto and Montreal.

But Manhattan also boasts a clear view of the horizon, looking across the Hudson River toward New Jersey. Plus you’ve got all those tall buildings lining the streets, creating the perfect vertical frame to show the setting sun to best advantage.

Read more at Discovery News

May 28, 2014

Iron Pin May Be Western Europe's Earliest False Tooth

The oldest false tooth yet seen in Western Europe may have been pulled from the earth during a 2009 archaeological excavation in northern France, reports BBC News.

The poorly preserved skeleton of a 20- to 30-year-old Iron Age woman, unearthed in Le Chene, suggests that an iron pin filled a place normally held by one of her upper incisors. Although it's not possible to confirm, the pin may have held in place a false wood or bone tooth that rotted away.

The woman's remains were part of a third-century B.C., Celtic burial enclosure that contained four adult females. In total, 31 of the woman's teeth were found in their correct anatomical locations, with the iron pin in the space where an incisor would normally have been.

The pin was the same size and shape as the surrounding teeth. "The best hypothesis is that it was a dental prosthesis, or at least, an attempt at one," Guillaume Seguin, who was in charge of the excavation and works with the Bordeaux archaeology firm Archeosphere, told BBC News.

Seguin expressed skepticism about whether the crude prosthesis would have performed well in its job as an implant. Iron tends to corrode in the body, and the third-century B.C. was not exactly a time in history where dental work could have guaranteed sterile conditions.

Lack of a sterile environment means the pin could well have caused an infection that took the woman's life.

But due to the poor state of her remains, there is no way to prove that a cosmetic procedure was the woman's ultimate undoing. The "tooth" may even have been inserted after the woman's death, as part of her burial process.

Read more at Discovery News

Rare Crusade-Era Seal Discovered in Jerusalem

A rare Crusade-era lead seal used to secure a letter was uncovered in an ancient farmstead in Jerusalem, the Israel Antiquities Authority announced today (May 27).

The 800-year-old seal was likely once fixed to a document delivered to the farm from a sprawling cliffside monastery in the Judean Desert that was founded by Saint Sabas ("Mar Saba" in Aramaic) and once housed hundreds of monks.

"This is an extraordinarily rare find, because no such seal has ever been discovered to date," Benyamin Storchan and Benyamin Dolinka, excavation directors from the Israel Antiquities Authority, said in a statement.

This type of ancient seal was also known as a bulla in Latin. It consisted of two blank lead disks that would have been hammered together with a string between them. Opening the letter would cause obvious damage to the bulla, which was intended to discourage unauthorized people from breaking the seal.

One side of the seal bears the image of the bearded Byzantine-era Saint Sabas, who is wearing a himation (essentially a Greek version of a toga), brandishing a cross in his right hand and perhaps holding a copy of the gospel in his left hand. The other side of the seal is etched with a Greek inscription, translated as: "This is the seal of the Laura of the Holy Sabas." (The monastery was also called the "Great Laura" of Mar Saba. A laura, or lavra, is a type of Orthodox Christian monastery that has a cluster of caves for hermit monks.)

"The Mar Saba monastery apparently played an important role in the affairs of the Kingdom of Jerusalem during the Crusader period, maintaining a close relationship with the ruling royal family," Robert Kool, a researcher with the Israel Antiquities Authority who examined the seal, said in a statement. "The monastery had numerous properties, and this farm may have been part of the monastery's assets during the Crusader period."

Read more at Discovery News

47-Million-Year-Old Bird Fossil May Be Oldest Pollinator

Pollen seeds found in the fossilized stomach of a tiny bird shows that birds and flowers have been linked for at least 47 million years.

Researchers discovered two types of seeds in the belly of the bird, called Pumiliornis tessellatus, plus nectar and insects. Finding the bird was a key way to confirm the likely presence of bird-pollinated plants, since other clues, such as red coloring and scent, vanish over time.

“The presence of pollen not only offers direct evidence of the bird’s feeding habits, but shows that birds already visited flowers as long as 47 million years ago,” said researcher Volker Wilde, a paleobotanist at the Senckenberg Research Institute in Frankfurt.

“We don’t just have a fossil that can tell us about the birds,” said study lead author Gerald Mayr, an ornithologist at the Senckenberg Research Institute in Frankfurt, Germany. “We have a unique sign that tells us about the special ecosystem it lived in. There’s a bigger story that this single skeleton can tell.”

The skeleton was found in an oil shale pit in Germany in 2012, and is the third Pumiliornis tessellatus ever found. It appears to have had a beak similar to a hummingbird’s, and four toes that it likely used to cling to branches while it sucked nectar.

From Discovery News

Oldest Traces of Life on Earth? Not So Fast

What were thought to be some of the oldest traces of life on Earth may not have been caused by life at all, new research suggests.

The fossils, tiny tubules etched into ancient rocks in South Africa, were initially thought to be formed by ancient bacteria boring through volcanic glass in the seafloor — a process called bioalteration — during the Archean Eon, about 3.4 billion years ago.

But the new study, published yesterday (May 26) in the journal Proceedings of the National Academy of Sciences, suggests these tiny tunnels were actually formed by the cooling of the volcanic rock nearby, just 2.9 billion years ago.

"Our new data challenges this complex 'bioalteration model' proposed to have occurred in the Archean pillow lava rims," study co-author Eugene Grosch, an earth scientist at the University of Norway, wrote in an email to Live Science.

Several fossils have vied for the title of Earth's oldest life. Geologists thought rippling, wavy textures imprinted into rocks in the Dresser Formation in western Australia may have been formed by microbial mats about 3.4 billion years ago. At another formation in western Australia known as Strelley Pool, domelike structures called stromatolites may also have been formed by microbes nearly 3.5 billion years ago.

And in 2004, researchers digging at the Barberton Greenstone Belt in South Africa identified the newly analyzed microscopic filament structures, made of a mineral called titanite, that they believed were formed by ancient microbes in oceanic crust about 3.49 billion years ago.

But finding the signature of tiny microbes that lived billions of years ago is extraordinarily difficult, and geologists hotly debate which of these specimens is truly the earliest hint of life on Earth.

Grosch and his colleague Nicola McLoughlin, an earth scientist at the University of Norway, weren't convinced that the Barberton textures were formed by ancient microbes. To test that idea, the team drilled 590 feet (180 meters) into the rock where the textures were found.

They measured hundreds of the textures throughout the core and analyzed their size and shape distribution. The filaments had huge diameters and a very large size distribution compared with those of the miniscule tunnels formed by microbes in oceanic crust today, Grosch said.

The team also used the decay of uranium and lead isotopes (elements with the same number of protons but a different number of neutrons) to estimate the age of the titanite. (Because these elements decay at different rates, the ratio of the two can reveal the age of the rock.)

The tiny trace fossils were formed between 2.9 billion and 2.8 billion years ago, so they're about 650 million years younger than the formation as a whole.

The team also used a mathematical model of the cooling conditions in nearby pillow lava and found that the titanite structures were likely formed by the prevailing conditions in the cooling rock at that time.

Read more at Discovery News

May 27, 2014

Light-colored butterflies and dragonflies thriving as European climate warms

Butterflies and dragonflies with lighter colours are out-competing darker-coloured insects in the face of climate change.

In a new study published in Nature Communications, scientists from Imperial College London, Philipps-University Marburg and University of Copenhagen have shown that as the climate warms across Europe, communities of butterflies and dragonflies consist of more lighter coloured species. Darker coloured species are retreating northwards to cooler areas, but lighter coloured species are also moving their geographical range north as Europe gets warmer.

For example, several Mediterranean dragonfly species have expanded their northern range and immigrated to Germany, such as the Southern Migrant Hawker (Aeshna affinis), the Scarlet Darter (Crocothemis erythraea) and the Dainty Damselfly (Coenagrion scitulum). In 2010, the Dainty Damselfly was also sighted in England for the first time in over 50 years. Butterfly species that thrive in warm climates, like the Southern Small White (Pieris mannii), have dispersed to Germany during the last ten years and are still continuing their northward shift.

As with lizards and snakes, the colour of an insect's body plays a key role in how they absorb energy from the sun, and is crucial in fuelling their flight as well as regulating their body temperature.

Dark-coloured insects are able to absorb more sunlight than light-coloured insects, in order to increase their body temperature, and are more likely to be found in cooler climates. In contrast, insects in hotter climates need to protect themselves against overheating. Light-coloured insects are more likely to be found in hotter climates as they can reflect the light to prevent overheating their body and be active for longer periods of time.

Carsten Rahbek, from the Department of Life Sciences at Imperial College London said: "For two of the major groups of insects, we have now demonstrated a direct link between climate and insect colour, which impact their geographical distribution."

"We now know that lighter-coloured butterflies and dragonflies are doing better in a warmer world, and we have also demonstrated that the effects of climate change on where species live are not something of the future, but that nature and its ecosystems are changing as we speak," concluded Professor Rahbek, who is also Director of the Center for Macroecology, Evolution and Climate at the University of Copenhagen. To identify whether colour lightness was correlated to temperature, the scientists combined digital image analysis, which scanned and measured colour values of butterfly and dragonfly wings and bodies, with distributional data which mapped where in Europe the species are found.

They looked at 366 butterfly species and 107 dragonfly species across Europe, and showed a clear pattern of light-coloured insects dominating the warmer south of Europe and darker insects dominating the cooler north.

To test whether a warming climate had caused any shifts, they looked at changes in species distributions over an 18-year period from 1988-2006. Results showed that on average insects were becoming lighter in colour, and that darker-coloured insects were shifting towards the cooler areas in Western margins of Europe, the Alps and the Balkans.

Read more at Science Daily

Biologists Find New Rules for Life at the Edge of Chaos

Detail from a computationally-modeled critical genetic network.
In the space between order and chaos, a zone usually described with the mathematics of impending avalanches and crystallizing liquids, scientists are finding new rules for life.

They’re researching the dynamics of criticality, where one system transforms rapidly into another. Scientists have studied such behavior in physical systems for decades; some have theorized that it might be found in living systems too, perhaps underlying some of biology’s fundamental and largely unexplained phenomena: how a few interacting genes shape an organism’s development, and how networked neurons give rise to complex cognitive functions.

Such speculation has been intriguing, but also difficult to study. Only now, with the advent of exquisitely sensitive biological probes and high-powered data analysis, have experiments started catching up to theory.

“In the past, there has been a lot of discussion about the potential benefits of biological systems poised at criticality,” said theoretical biophysicist Dmitry Krotov of Princeton University, co-author of a Feb. 10 Proceedings of the National Academy of Sciences paper on criticality in genetic networks. “Now high-quality experimental data are appearing, and we are able to quantitatively test these ideas.”

In the new study, Krotov and co-author William Bialek, also a biophysicist at Princeton, measured protein-coding activity in a genetic network crucial to the development of fruit fly embryos. Expressed in mathematical terms, the activity contained the signatures — relationships between gene activity, patterns of correlation at far-flung locations in embryos — characteristic of criticality.

The study is just one data point, a bit of extra weight on the evidentiary scale. But other researchers have made similar findings, observing apparently critical patterns in the genetic networks of single-celled and also multicellular organisms. Criticality seems to be an integral part of life.

Presence alone doesn’t signify importance, but the essential properties of critical networks should make them useful to biological systems, said physicist Maximino Aldana of the National Autonomous University of Mexico. His work suggests criticality could be an optimal evolutionary solution for systems that need to balance resilience with adaptability.

Another key feature of critical networks is the speed at which information passes through them. Though easier to describe in the rarefied language of statistical biophysics than in conversational terms, a tangible example comes from Bialek’s work on flocks of starlings, which fly in critically networked formations. Within them, thousands of birds move with uncanny coordination, with individual movements rippling almost instantaneously across the entire group.

Another instructive analogy, said biophysicist John Beggs of Indiana University, is of sand grains dropped one-by-one from a single point. For a long time, nothing much happens: a conical pile slowly accumulates. Eventually, however, it becomes so steep that the addition of just one more grain can trigger a miniature avalanche, though not in a predictable way. Avalanches can be small or large, and sometimes they don’t happen at all.

Just before the pile enters its avalanche-prone state, said Beggs, it’s poised at criticality. From a biological perspective, the trick is to harness the capacity for small perturbations — such as a protein’s presence or a neuron’s firing — to produce large effects without entirely entering that avalanche-prone state, in which perturbations would soon become overwhelming. Researchers studying such behaviors sometimes refer to this as the “edge of chaos.”

“You’ve got randomness, and you’ve got order. And right between them, you’ve got the phase transition,” Beggs said. “The idea is, you want to get as close as possible to chaos, but you don’t want to go into the chaos. You want to be on the edge, on the safe side.”

Beggs’ own research involves these avalanche behaviors in networks of neurons. These have been documented at small scales encompassing a few hundred or thousand cells, and also in large-scale, across-the-brain activity in organisms as disparate as roundworms and humans.

It’s been proposed that these criticalities may underlie cognition — the extraordinary dynamics of memory formation and sensory integration and on-the-fly processing — and even be involved in cognitive disorders, though these remain open and largely untested questions.

“It’s not clear how critical this phenomenon is to biology,” cautioned Krotov. He characterized the present state of research as one in which scientists, flush with results from early rounds of experiments, can now refine and update their models of criticality, and use those to inform new investigations.

One important insight, said Krotov, is that criticality in biology won’t precisely resemble what’s seen in the classical, physical systems where criticality was first studied. In the latter — the aforementioned pile of sand, or magnets losing their magnetization at high temperatures — criticality is a global property, the same at every point in a system. Biology could involve many critical networks, nestled together in hierarchies that generate ever more complex phenomena.

Another open question is whether criticality is found at even higher scales. Apart from group dynamics — in addition to starlings, crowds of people sometimes seem to be poised at the edge of chaos — criticality may even operate at ecological levels. This has primarily been studied in a catastrophic context, as when a diseased coral reef turns into an underwater desert, but it’s possible that communities of plants and animals also function as information-processing networks, exhibiting what one speculative early paper described as “coevolution to the edge of chaos.”

“Maximum information at a state of criticality in biodiversity has not been explored so much,” said ecologist Marten Scheffer of Wageningen University, who specializes in ecological tipping-point dynamics. “It’s a potentially interesting area.”

Read more at Wired Science

How a Swinging Pendulum Proves the Earth Rotates

Once upon a time, you were probably on an elementary school field trip at a science museum or an observatory. Just before lunch, your teacher had the class stand in a circle around an enormous weight suspended on a string, and watch it swing back and forth, back and forth.

The teacher (or maybe a tour guide) explained that if you watched the pendulum for long enough, it would seem to alter its course, swinging in a slightly different direction. And that this somehow proved the Earth was rotating beneath your feet. You probably nodded and watched the weight swing for a while. And even though you didn’t see anything really change, you thought, “Sure,” and then went to trade your friend an Oreo cookie for half of their Hi-C Ecto Cooler.

Now that you’re older, you’ll occasionally think back on that pendulum and wonder how it could have proved anything. After all, the demonstration was in a building on the Earth, so if the Earth was rotating, shouldn’t the pendulum be rotating with it?

This famous experiment, now found in museums around the world, was first demonstrated in 1851. French physicist Leon Foucault suspended a 61-pound weight from a 200-foot-long wire at the Pantheon in Paris and set it swinging. He needed the bob to be so heavy and the wire so long to ensure that the pendulum would be able to swing for a long time, at least an hour. A pin on the bottom of the weight drew a line in a circle of wet sand set underneath the experiment.

After an hour, the line the pin drew in the sand intersected with the first line at an angle of roughly 11.25 degrees, which is exactly what Foucault had predicted. The demonstration was an international sensation and was quickly repeated to crowds across Europe and North America. By this point, everyone knew that the Earth rotated but this was the first experiment to measure the speed at which it did so. Foucault got eternal fame by having a pendulum named after him, which later became the title of a mind-bending book by Umberto Eco you probably tried to read in college before turning to the much easier candy of Dan Brown novels.

So how does this all work? To explain, we’re going to have to do a little thought experiment.

Let’s say that one day you and a friend decide to play a game of catch at the North Pole (your friend is an eccentric billionaire in this story). You stand on one side of the pole and toss the ball directly over the pole to your friend, who is standing opposite you. Try to think about things from the ball’s perspective. At the moment it’s released from your hand, its path is set. It will travel in a straight line toward the point that you threw it. But in the time it takes the ball to travel, the Earth has rotated just a tiny bit. Your friend has moved ever so slightly to the right. This movement is so minute that it’s hardly going to affect your game of catch. But if you were on a planet with a very fast rotation rate, your friend would have moved much more in the time it takes the ball to travel. The ball could entirely miss your friend, going straight past her left arm.

As it goes through its swing, the pendulum acts like this ball. Once the pendulum reaches the top of its arc, its path is set. It will head to the opposite end of its swing without deviation. Essentially, it will continue swinging back and forth in the same exact plane. Imagine you’ve suspended the pendulum over the North Pole. You glue a pin to its bottom and send it swinging, drawing a line in the snow. But in the time it takes to go from one top of an arc to the next, the Earth underneath the experiment has rotated. And each time the pendulum swings; the Earth rotates a little more. If you kept the pendulum swinging for six hours, one-quarter of a day, the line it now traced in the snow would intersect the first line at 90 degrees. (Note: Some truly awesome and dedicated physicists did this in 2001 at the South Pole.)

Those of you checking my math will probably now interject something like this: “But you said that Foucault’s pendulum in Paris moved 11.25 degrees in one hour, which means it would have only changed by 67.5 degrees in six hours, not 90 degrees.” Well congratulations, you’ve shown that the thought experiment we did above only works at either the North or South Pole. And also, that you are a nerd.

Imagine the same setup at the equator. You start the pendulum swinging in a perfect east-west direction. The Earth still rotates each time the weight goes through an arc, but now it’s moving in exactly the same direction as the pendulum. There’s no relative motion. Think about this carefully. I can set the pendulum swinging north-south and the Earth’s rotation still won’t affect the plane it moves in. That’s because the Earth can’t twist underneath the setup; it’s always headed in the same direction.

Read more at Wired Science

Peat Bog the Size of England Discovered in Congo

A massive peat bog covering some 40,000 to 80,000 square miles has been discovered in the central African nation of the Democratic Republic of the Congo, reported the BBC.

After satellite images suggested what could be a huge tropical peatland -- about the size of England, according to the BBC -- in a remote area of Congo-Brazzaville, a research team from the University of Leeds, the Wildlife Conservation Society-Congo, and Congo-Brazzaville's Marien Ngouabi University ventured into the soggy area and confirmed its presence.

Peat is formed when plant matter does not fully decompose and sinks over time into the soil. The peat-layer in the enormous bog reaches nearly 23 feet beneath the ground and contains billions of tonnes of ancient, partially decayed vegetation, researchers said.

"Peatlands, generally, have been a big carbon sink over the past 10,000 years," the University of Leeds' Dr. Simon Lewis told BBC News. With so much organic matter caught so deep in the carbon-packed soil, the team hopes peat samples taken from the area will help shed more light on Earth's distant-past climate.

Besides its sheer size, another thing that makes the peat bog discovery amazing is its location in a tropical climate, Lewis said. Peatlands generally need colder areas that will slow vegetation decomposition. "It's rare to find them in the wet and warm tropics, so that makes this an unusual discovery," he said.

The peat samples taken from the expedition have been sent to the United Kingdom for analysis.

From Discovery News

May 26, 2014

Molecules do the triple twist

An international research team led by Academy Professor Kari Rissanen of the University of Jyväskylä (Finland) and Professor Rainer Herges of the University of Kiel (Germany) has managed to make a triple-Möbius annulene, the most twisted fully conjugated molecule to date, as reported in Nature Chemistry.

An everyday analogue of a single twisted Möbius molecule is a Möbius strip. It can be made easily by twisting one end of a paper strip by 180 degrees and then joining the two ends. A triple twisted Möbius molecule is more difficult to visualize, but its graphical representation resembles the well-known recycling logo, this time with three twisted corners.

However, it has turned out to be extremely difficult to twist molecules to a Möbius surface that has only one side. Up to now, only the simplest Möbius molecules have been prepared. Now Dr. Gaston Schaller and Professor Rainer Herges from the University of Kiel and M.Sc. Filip Topić and Academy Professor Kari Rissanen from the University of Jyväskylä, together with Professor Yoshio Okamoto (Osaka, Japan) and Jun Shen (Harbin, China), have succeeded in preparing and characterizing a triple twisted annulene -- a more complex Möbius molecule which has three twists but only one surface.

Currently these chiral one-sided compounds are merely scientifically intriguing topological objects and far from practical application, but they exhibit a high potential in future applications in molecular electronics and optoelectronics.

From Science Daily

Insights into genetics of cleft lip

Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, have identified how a specific stretch of DNA controls far-off genes to influence the formation of the face. The study, published today in Nature Genetics, helps understand the genetic causes of cleft lip and cleft palate, which are among the most common congenital malformations in humans.

"This genomic region ultimately controls genes which determine how to build a face and genes which produce the basic materials needed to execute this plan," says François Spitz from EMBL, who led the work. "We think that this dual action explains why this region is linked to susceptibility to cleft lip or palate in humans."

Previous studies had shown that variations in a large stretch of DNA are more frequent in people with cleft lip or cleft palate. But there are no genes in or around this DNA stretch, so it was unclear what its role might be. To answer this question, Spitz and colleagues genetically engineered mice to lack that stretch of DNA, as the mouse and human versions are very similar, and are therefore likely to have the same role in both species. They found that these genetically engineered mice had slight changes to the face -- such as a shorter snout -- and a few had cleft lips. The scientists also used this mouse model to look at what happened during embryonic development to lead to those changes.

"We found that this stretch of DNA contains regulatory elements that control the activity of a gene called Myc, which sits far away on the same chromosome," Spitz explains, "and it exerts that control specifically in the cells that will form the upper lip."

The researchers discovered that, in the face of mouse embryos that lack this stretch of DNA, Myc becomes largely inactive. This in turn affects two groups of genes: genes directly involved in building the face, and genes that make ribosomes, the cell's protein-producing factories. The latter effect could make the developing upper lip more sensitive to other genetic conditions and to environmental factors -- like smoking or drinking during pregnancy -- that can influence cell growth. This is because making the face in general, and the upper lip in particular, are very complex processes, requiring different groups of cells in the embryo to grow and fuse with each other at the right time. If the cells involved have their protein production impaired -- due to reduced Myc activity -- any additional burden could disrupt that growth, increasing the likelihood of a malformation like cleft palate. This increased susceptibility to a wide range of factors -- both genetic and environmental -- could the link between variations in this stretch of DNA and the incidence of cleft lip.

Read more at Science Daily

Sound and vision: Visual cortex processes auditory information, too

Scientists studying brain process involved in sight have found the visual cortex also uses information gleaned from the ears as well as the eyes when viewing the world.

They suggest this auditory input enables the visual system to predict incoming information and could confer a survival advantage.

Professor Lars Muckli, of the Institute of Neuroscience and Psychology at the University of Glasgow, who led the research, said: "Sounds create visual imagery, mental images, and automatic projections.

"So, for example, if you are in a street and you hear the sound of an approaching motorbike, you expect to see a motorbike coming around the corner. If it turned out to be a horse, you'd be very surprised."

The study, published in the journal Current Biology, involved conducting five different experiments using functional Magnetic Resonance Imaging (fMRI) to examine the activity in the early visual cortex in 10 volunteer subjects.

In one experiment they asked the blindfolded volunteers to listen to three different natural sounds -- birdsong, traffic noise and a talking crowd.

Using a special algorithm that can identify unique patterns in brain activity, the researchers were able to discriminate between the different sounds being processed in early visual cortex activity.

A second experiment revealed even imagined images, in the absence of both sight and sound, evoked activity in the early visual cortex.

Lars Muckli said: "This research enhances our basic understanding of how interconnected different regions of the brain are. The early visual cortex hasn't previously been known to process auditory information, and while there is some anatomical evidence of interconnectedness in monkeys, our study is the first to clearly show a relationship in humans.

"In future we will test how this auditory information supports visual processing, but the assumption is it provides predictions to help the visual system to focus on surprising events which would confer a survival advantage.

Read more at Science Daily

Buried fossil soils found to be awash in carbon

Soils that formed on Earth's surface thousands of years ago and that are now deeply buried features of vanished landscapes have been found to be rich in carbon, adding a new dimension to our planet's carbon cycle.

The finding, reported in the journal Nature Geoscience, is significant as it suggests that deep soils can contain long-buried stocks of organic carbon which could, through erosion, agriculture, deforestation, mining and other human activities, contribute to global climate change.

"There is a lot of carbon at depths where nobody is measuring," says Erika Marin-Spiotta, a University of Wisconsin-Madison assistant professor of geography and the lead author of the new study. "It was assumed that there was little carbon in deeper soils. Most studies are done in only the top 30 centimeters. Our study is showing that we are potentially grossly underestimating carbon in soils."

The soil studied by Marin-Spiotta and her colleagues, known as the Brady soil, formed between 15,000 and 13,500 years ago in what is now Nebraska, Kansas and other parts of the Great Plains. It lies up to six-and-a- half meters below the present-day surface and was buried by a vast accumulation of windborne dust known as loess beginning about 10,000 years ago, when the glaciers that covered much of North America began to retreat.

The region where the Brady soil formed was not glaciated, but underwent radical change as the Northern Hemisphere's retreating glaciers sparked an abrupt shift in climate, including changes in vegetation and a regime of wildfire that contributed to carbon sequestration as the soil was rapidly buried by accumulating loess.

"Most of the carbon (in the Brady soil) was fire derived or black carbon," notes Marin-Spiotta, whose team employed an array of new analytical methods, including spectroscopic and isotopic analyses, to parse the soil and its chemistry. "It looks like there was an incredible amount of fire."

The team led by Marin-Spiotta also found organic matter from ancient plants that, thanks to the thick blanket of loess, had not fully decomposed. Rapid burial helped isolate the soil from biological processes that would ordinarily break down carbon in the soil.

Such buried soils, according to UW-Madison geography Professor and study co-author Joseph Mason, are not unique to the Great Plains and occur worldwide.

The work suggests that fossil organic carbon in buried soils is widespread and, as humans increasingly disturb landscapes through a variety of activities, a potential contributor to climate change as carbon that had been locked away for thousands of years in arid and semiarid environments is reintroduced to the environment.

The element carbon comes in many forms and cycles through the environment -- land, sea and atmosphere -- just as water in various forms cycles through the ground, oceans and the air. Scientists have long known about the carbon storage capacity of soils, the potential for carbon sequestration, and that carbon in soil can be released to the atmosphere through microbial decomposition.

Read more at Science Daily

May 25, 2014

Untangling whole genomes of individual species from a microbial mix

A new approach to studying microbes in the wild will allow scientists to sequence the genomes of individual species from complex mixtures. It marks a big advance for understanding the enormous diversity of microbial communities -- including the human microbiome. The work is described in an article published May 22 in Early Online form in the journal G3: Genes|Genomes|Genetics, published by the Genetics Society of America.

"This new method will allow us to discover many currently unknown microbial species that can't be grown in the lab, while simultaneously assembling their genome sequences," says co-author Maitreya Dunham, a biologist at the University of Washington's Department of Genome Sciences.

Microbial communities, whether sampled from the ocean floor or a human mouth, are made up of many different species living together. Standard methods for sequencing these communities combine the information from all the different types of microbes in the sample. The result is a hodgepodge of genes that is challenging to analyze, and unknown species in the sample are difficult to discover.

"Our approach tells us which sequence fragments in a mixed sample came from the same genome, allowing us to construct whole genome sequences for individual species in the mix," says co-author Jay Shendure, also of the University of Washington's Department of Genome Sciences.

The key advance was to combine standard approaches with a method that maps out which fragments of sequence were once near each other inside a cell. The cells in the sample are first treated with a chemical that links together DNA strands that are in close proximity. Only strands that are inside the same cell will be close enough to link. The DNA is then chopped into bits, and the linked portions are isolated and sequenced.

Read more at Science Daily

Tiny muscles help bats fine-tune flight, stiffen wing skin

Bats appear to use a network of hair-thin muscles in their wing skin to control the stiffness and shape of their wings as they fly, according to a new study. The finding provides new insight about the aerodynamic fine-tuning of membrane wings, both natural and human-made.

A new study of bats reveals a capability within their wondrous wings that may help them fine-tune their flight.

Bats employ a network of nearly hair-thin muscles embedded in the membrane of their inherently floppy wing skin to adjust the wings' stiffness and curvature while they fly, Brown University researchers report. Birds and insects have stiff wings, but the new evidence suggests bats have evolved this muscular means of preserving or adjusting wing shape.

"Aerodynamic performance depends upon wing shape," said Brown biology graduate student Jorn Cheney, lead author of the newly published paper in Bioinspiration and Biomimetics. "The shape of a membrane wing might initially begin flat but as soon as it starts producing lift it's not going to remain flat because it has to deform in response to that aerodynamic load.

"The shape it adopts could be a terrible one -- it could make the animal crash -- or it could be beneficial," Cheney said. "But they are not locked into that shape. Because bats have these muscles in their wings, and also bones that can control the general shape as well, they can adopt any number of profiles."

Membrane muscle measurements

Cheney wasn't sure what to make of the tiny muscles, called plagiopatagiales, heading into the experiments reported in the paper. They have been known for more than a century but their function has never been demonstrated.

When Cheney considered the muscle function, he estimated that each individual muscle would be too weak to reshape the wing. That led him to form two competing hypotheses: either that the muscles would activate together to enhance force or that these oddly shaped, weak muscles might exist solely as sensors of stretch.

Only experiments could settle the question, so Cheney attached electrode sensors to a few muscles on the wings of a few Jamaican fruit bats and filmed them as they flew in the lab's wind tunnel.

Three key findings emerged from the data. They all point to the plagiopatagiales modulating skin stiffness.

One result was that the muscle activation and relaxation follows a distinct pattern during flight: They tense on the downstroke and relax on the upstroke.

"This is the first study showing that bats turn these muscles on and off during a typical wingbeat cycle," said co-author Sharon Swartz, professor of biology at Brown.

.Another finding was that the muscles don't act individually. Instead they exert their force in synchrony, providing enough collective strength to stiffen the wing.

Finally, Cheney found, the muscles appeared to activate with different timing at different flight speeds. As the bats flew faster, they tensed the muscles sooner in the upstroke-downstroke cycle.

In other words, the data suggested that the muscles do not behave passively but actively and collectively in keeping with conditions of flight.

None of the data, however, preclude the muscles from serving a sensory function as well.

Technological insight, too

Cheney's findings fit into a larger program of research at Brown between the labs of biologist Swartz and co-author Kenneth Breuer, professor of engineering, in which, as Breuer puts it, they are "using biology to inspire engineering and using engineering to inspire biology."

In parallel with studies of real bats, the team has also built a robotic bat wing that incorporates their biological observations. Then they use the wing to generate data from experiments that they could never do with living creatures, such as precisely varying kinematic parameters like wingbeat frequency and amplitude, or the degree of wing folding during flapping.

In a separate paper in the same edition of Bioinspiration and Biomimetics, Swartz, Breuer, and former student Joe Bahlman report on how energy costs and aerodynamic forces changed as they varied several kinematic parameters in the robotic bat wing. They found that to generate a given force, such as lift, each of several parameters requires about the same amount of energy, but that the timing and extent of wing folding varies the ratio between lift and power significantly.

Read more at Science Daily