Lasers Zap Heads of Flies to Expose Brains

Using lasers, scientists can now surgically blast holes thinner than a human hair in the heads of live fruit flies, allowing researchers to see how the flies' brains work.

The researchers also successfully tested this technique on worms, ants and mice.

Microscopically peering into living animals can help scientists learn more about key details of these animals' biology. For instance, tiny glass windows surgically implanted into the sides of living mice  can help researchers study how cancers develop in real time and evaluate the effectiveness of potential medicines.

Surgically preparing small live animals for such "intravital microscopy" is often time-consuming and requires considerable skill and dexterity. Now, Supriyo Sinha, a systems engineer at Stanford University in California, and his colleagues have developed a way to prepare live animals for such microscopy that is both fast -- taking less than a second -- and largely automated.

Fruit-fly brains

To conduct this procedure, scientists first cooled fruit flies to anesthetize them. Then, the researchers carefully picked up the insects with tweezers and glued them to the tops of glass fibers in order to immobilize the flies' bodies and heads. Then, using a high-energy pulsed ultraviolet laser, the researchers blasted holes measuring 12 to 350 microns wide in the flies' heads. (In comparison, the average human hair is about 100 microns wide.) They then applied a saline solution to exposed tissue to help keep the fly brains healthy. (See Experiment Video).

The scientists then microscopically analyzed brain activity in the fruit flies. The insects in the experiment were genetically modified to generate a protein that emits a green glow in the presence of calcium ions, the flow of which is key to neural activity. By looking through these "windows" into the fruit flies' heads, the researchers successfully monitored calcium-ion-based activity in neurons in response to different smells.

Using lasers enabled the researchers to create these "windows" up to 100 times faster than they could be created manually. Moreover, these laser-cut windows were apparently substantially gentler on fly health than ones created by conventional surgery -- the researchers could image brain activity for longer than they could using the conventional method, up to 18 hours, about five to 20 times longer than prior microscopy studies of living, hand-dissected flies.

"The induced trauma to the fly is minimized, and the fly can remain alive longer," Sinha told LiveScience. "Learning and memory experiments in which the brain is imaged before and after training is possible."

Prior research had tried using laser surgery to open holes in animals for intravital microscopy before. Compared to past work that used infrared, visible or larger-wavelength ultraviolet lasers, this new technique can remove tissue more quickly or cause less collateral damage in the brain.

Sinha and his colleagues also successfully tested their technique on anesthetized and immobilized ants, nematode worms and mice. "Our main motivation is to better understand neural circuits, and faster screening and imaging could better help us reverse-engineer these circuits," Sinha said.

From one to 100

The scientists are also developing a way to automatically capture, mount and align the insects for laser surgery. Their short-term goal is to build a system that can hold a dozen flies.

"We are trying to streamline the procedure such that the experimentalist only has to press one button to have the system pick and mount and align 12 flies; a second button that would surgically remove the cuticle and apply saline to the 12 flies; and a third button to start imaging the 12 flies under predetermined stimulation," Sinha said.

Ultimately the researchers would like to simultaneously image the brains of about 100 awake fruit flies with a push of a few buttons, Sinha added.

Read more at Discovery News

Finned Monster Bit Heads Off Ancient Amphibians

DENVER — Talk about a creature feature: A bizarre boomerang-headed amphibian that burrowed in a seasonal pond in what is now Texas often met its doom in the jaws of a reptilian fin-backed mammalian ancestor, new fossils reveal.

These two weird critters were residents of the Permian period 298 million to 250 million years ago, before dinosaurs roamed the Earth. Dimetrodon, the jaguar-size finback, looked like a lizard but was actually more closely related to modern mammals. Diplocaulus, the boomerang-head, was a truly strange amphibian with an impractically wide, bony skull.

"It's just so weird," said study researcher Robert Bakker, the curator of paleontology at the Houston Museum of Natural Science. "This is an example of unintelligent design."

Unintelligent though a broad head may have been for a burrowing creature, the boomerang-head managed to survive for 45 million years during the Permian, a period known for its extinctions, Bakker told LiveScience.

Bakker and his colleagues discovered the Dimetrodonand Diplocaulus interaction in the Craddock bone bed in Baylor County, Texas. The bone bed is scattered with the bodies of boomerang-heads, curled in what were once burrows. The amphibians seem to have burrowed into the mud to survive the dry season, the researchers reported here Monday (Oct. 28) at the annual meeting of the Geological Society of America.

"The bed had a reputation of just being a stewpot with everything mixed together," Bakker said. "That's totally wrong. It's beautifully layered."

The excavations revealed that boomerang-heads were common in the pond — and that something was snacking on them.

"We have hundreds of these, mostly chewed, and even the guys in burrows got attacked," Bakker said.

The shed teeth, "like bullets in a crime scene," revealed the attacker to be Dimetrodon, he said. The finback's sharp fangs and long snout would have enabled it to bite boomerang-heads hiding in burrows, perhaps after partially excavating them with its sharp, digging claws.

One cluster of eight juvenile boomerang-heads was found stacked together, suggesting they all occupied the same burrow. Dimetrodon likely killed the top three, including one whose nose was bitten clean off (taking part of the brain with it). The other five boomerang-heads survived the Dimetrodon, only to perish during the next dry season, Bakker said.

Read more at Discovery News

Supervolcanoes Found in Maine! (Yes, Maine)

Maine has supervolcanoes. Wait, Maine has volcanoes? Yes, and their eruptions could have been among the biggest ever on Earth, geoscientist Sheila Seaman reported here Tuesday (Oct. 29) at the Geological Society of America's annual meeting.

"Long before there were these things called supervolcanoes, we've known about giant, big, horrific silicic volcanic eruptions," said Seaman, of the University of Massachusetts at Amherst. The most massive of these blasts in recent history was Toba, which blew up an island in Indonesia 2.5 million years ago. The explosion heaved 700 cubic miles (2,800 cubic kilometers) of magma out of the Earth's crust.

Around 420 million years ago, a series of super-eruptions dropped thick piles of ash and lava fragments along the proto-East Coast. There are at least four volcanoes spread out along 100 miles (160 km) of Maine's coast, Seaman said.

The huge volcanic rock piles are consistent with caldera-forming eruptions, Seaman said. These explosions empty a magma chamber, leaving a gaping wound in the Earth — think Yellowstone National Park, or the San Juan volcanic field in Colorado.

Since they formed, the ancient volcanic layers have been tilted up by tectonic forces, providing a top-to-bottom slice through a supervolcano. For example, Isle au Haut, part of Acadia National Park, exposes the heart of a volcano. "The whole magma chamber is lying on its side," Seaman said.

Building on years of geologic mapping and tectonic reconstructions by other researchers, Seaman has traced a direct connection between the cooled and crystallized magma chambers, called plutons, and their enormous ash deposits.

Volcanic rock layers on Maine's Cranberry Island have a 2,300-foot-thick (700 meters) layer of welded tuff, a rock formed from volcanic ash. The welded tuff from Toba's most recent blowout is 2,000 feet (600 m) thick, Seaman said. On the remote Isle au Haut, part of Acadia National Park, the volcanic rocks are more than 3 miles (5 km) thick, Seaman said. They're capped by an immense ash flow, more than 3,200 feet (1 km) thick.

Seaman estimates the caldera at Mount Desert Island would have been about 15 miles long and 15 miles wide (25 km by 25 km). For comparison, Toba's caldera is 62 miles long and 18 miles wide (100 km by 30 km).

"The coast is so serene and so beautiful and has such a terrible, violent past," Seaman told LiveScience's OurAmazingPlanet.

Seaman thinks the super-eruptions struck between 424 million to 419 million years ago, in the Silurian period, after islands the size of Japan slammed into the eastern edge of Laurentia, the continental core of North America. Afterward, tectonic forces stretched and tore Earth's crust behind the collision zone, making space for magma to rise from the mantle, the layer beneath the crust.

Read more at Discovery News

'Hybrid' Solar Eclipse to Dazzle on Sunday

The moon will blot out the sun Sunday (Nov. 3) in an eclipse that will be visible from eastern North America to the Middle East.

Sunday's celestial event is a relatively rare occurrence known as a hybrid solar eclipse. It will begin as an annular or "ring of fire" eclipse along the path of totality, then shift to a total eclipse as the moon's shadow sweeps across our planet.

What you'll observe depends on where you live. Skywatchers in the eastern United States, northeastern South America, southern Europe, the Middle East and most of Africa will be treated to a partial solar eclipse, while people along the path of totality in central Africa will see the sun totally obscured by Earth's nearest neighbor for a few dramatic moments.

If you live in eastern North America, you'll have to get up early to enjoy the show. The partial eclipse will be visible at sunrise — about 6:30 a.m. local time — and last for about 45 minutes, experts say. Viewers in Boston and New York will see the sun more than 50 percent covered by the moon, while our star will appear 47 percent obscured from Miami and Washington, D.C.

All of the action in this part of the world will be occurring low in the sky, less than 8 degrees from the east-southeast horizon. (Your fist held at arm's length measures about 10 degrees.) So you'll want to find a spot that affords a good look at the horizon, without any buildings or hills blocking the view.

The path of totality, meanwhile, starts in the Atlantic Ocean off the eastern U.S. and runs through Gabon, the Democratic Republic of Congo, and several other African nations before petering out in southern Ethiopia and Somalia around sunset.

Read more at Discovery News

Viking Graves Yield Grisly Find: Sacrificed Slaves

Viking graves in Norway contain a grisly tribute: slaves who were beheaded and buried along with their masters, new research suggests.

In Flakstad, Norway, remains from 10 ancient people were buried in multiple graves, with two to three bodies in some graves and some bodies decapitated. Now, an analysis reveals the beheaded victims ate a very different diet from the people with whom they were buried.

"We propose that the people buried in double and triple burials might have come from very different strata of society, and that slaves could have been offered as grave gifts in these burials," study co-author Elise Naumann, an archaeologist at the University of Oslo in Norway, wrote in an email.

Viking age

From about the 790s until about A.D. 1100, the Vikings were fierce, sea-faring raiders and often took slaves as booty. But this vicious lifestyle wasn't a full-time job. In everyday life, many Vikings were actually farmers, relying on slaves, or thralls, for agricultural work. Though some thralls were treated well, many were forced to endure backbreaking physical labor, Naumann said. Women were often used as sex slaves, and any children who resulted could either be considered the master's children or treated as slaves themselves.

The Viking burials were first discovered in the early 1980s, but only partially excavated at the time. The ancient graves were partly damaged by modern farming and contained just a few grave artifacts, such as an amber bead, some animal bones and a few knives. At the time, archaeologists noticed that four of the bodies were beheaded whereas the rest were intact.

That led many to conclude that the decapitated bodies were those of slaves sacrificed and buried with their masters.

Different classes

To bolster that notion, Naumann and her colleagues analyzed the skeletons' mitochondrial DNA, which is passed on through the maternal line. The team found that bodies buried together were most likely not related, at least on the maternal side.

Next, they analyzed the ratio of carbon and nitrogen isotopes, or elements with different molecular weights, in the bones of the ancient Scandinavians.

Because food that comes from the sea or the land contains different proportions of heavy and light isotopes of carbon and nitrogen, the concentration of these chemicals in bones can reveal the dietary history of a people.

Results showed the beheaded people ate more fish protein, whereas the others ate land-based protein sources, such as meat and dairy products. That suggests the people buried together came from very different strata of society.

Grave gifts

Naumann proposes the beheaded victims were slaves who were sacrificed as gifts to be offered in death on behalf of their masters. Though such human sacrifice was uncommon in Viking society, it wasn't unknown.

Read more at Discovery News

Why Do We Connect Halloween and Satanism?

For most people Halloween is a fun time of dressing up, creating elaborate costumes and decorations, visiting haunted houses, taking kids trick-or-treating, and of course eating candy. It has become a heavily commercialized holiday second only to Christmas in terms of the number of people who celebrate and participate in it.

For some, however, the fears associated with Halloween go beyond fake-scary ghosts and into genuine spiritual warfare for the souls of the innocent. These people, including many fundamentalist Christians, believe that there is a dark and sinister side to the Oct. 31 festivities. Where did this belief come from?

Fear of Witches

Part of the answer lies in the reputed origins of Halloween. Many trace it back to an ancient Celtic pagan celebration called Samhain (pronounced “sah-win”). Samhain, which occurred on Halloween, the night before All Saint’s Day, was an annual communal meeting to gather resources for the winter months.

Samhain has many aspects but focused on the changing of seasons and preparing for the dormancy (and eventual rebirth) of nature as summer turned to winter. These pre-Christian practices, with their focus on nature’s cycles and many deities, were viewed as occult by the Roman Catholic Church. All Saint’s Day and Samhain, coming so close together on the calendar, influenced each other and, many believe, later combined into the celebration we now call Halloween.

Then there’s the fact that the Bible is pretty clear about its position on magic and the occult  — for example Exodus 22:18 commands that “Thou shalt not suffer a witch to live.” Because witchcraft is seen as an abomination in the eyes of God — along with other occult practices such as dowsing, astrology and Ouija boards — anything associated with it is to be shunned as evil.

Still, you may ask, what’s the big deal? What, exactly, is the link between the Devil and the day kids dress up as ghosts, Spider-Man or Shrek? Christian evangelist Phil Phillips and Joan Hake Robie, in their book “Halloween and Satanism,” explain why many fundamentalists are concerned about Halloween: “A tragic by-product of fear in the lives of children as early as pre-pubescence is the interest and involvement in supernatural occult phenomena.”

Thus, they believe, if a child is scared by a haunted house zombie or spooky witch costume, his or her natural curiosity will soon lead them to read books and watch TV programs on the things that scared them — dead bodies or witches, for example. According to Phillips and Robie, this will start children on the road to Satanic practices.

Of course, it’s true that Halloween practices — like Christmas, Thanksgiving, and other holiday practices and rituals — have a historical context and make use of certain symbols, foods, music and so on. However just because there exists a long history of real, genuine witchcraft claims — such as those that resulted in the infamous Salem witch trials of 1692 — doesn’t mean that any child who sees a green-skinned, pointy-hatted witch costume will become interested in magic or witchcraft, much less become a witch.

Unlike concerned adults who read sinister meanings into things they fear or shun, children tend to take things at face value. They are more concerned about how much candy they get — or how good their costume is — than whether their black cat lawn ornament is really an invitation for Satan.

Halloween is only a high-profile part of the problem. Role-playing games like Dungeons and Dragons, the Harry Potter books, and even popular films like “E.T.: The Extraterrestrial” and “Ghostbusters” are also gateways to sin. Rap music, violent cartoons and video games, and so on are all evidence of social moral decay leading to drug use, suicide and murder. Underlying all this is a conspiracy-theory like belief that there are hidden meanings behind everything, and powerful, sinister forces at work trying to brainwash the innocent.

Halloween, Samhain and Satan

The connection between Satanism and Halloween is even less plausible in historical context. Though a clear and direct historical connection between Halloween and Samhain has never been proven, many scholars — and the public — believe that the traditions are linked.

As for the allegedly sinister nature of that ancient Celtic feast, Nicholas Rogers, a history professor at York University and author of “Halloween: From Pagan Ritual to Party Night,” writes:

“We can dismiss the argument that Samhain was ‘satanic’ or that in some essentialist sense Halloween is a ‘satanic ritual,’ as the Reverend Pat Robertson, the founder of the Christian Coalition, declared in 1982…. Satanism is essentially a Christian creation, a travesty of Christian forms centered on the fallen rebel angel Lucifer. In fact, the early Christian church left little room for Satan… Certainly, Satanism was incompatible with the polytheism of the ancient Celts. Indeed, the belief in satanic cults blossomed only in the late medieval period — long after the demise of Samhain.”

The confusion may have arisen, in part, because Wiccan witchcraft traditions worship a horned god which superficially resembles depictions of a goat-headed Devil. This “Horned One,” however, is a god of fertility (among other things). Since these early pagans did not believe in anything resembling a Christian Satan, it could not have played a role in their rituals.

Hell Houses for Jesus

Despite no evidence that Halloween is satanic or occult, some religious organizations have tried to ban the holiday. Nicholas Rogers writes:

“Christian fundamentalists have taken exception to Halloween school parties on the grounds that they insidiously promote pagan, if not satanic, beliefs. There have been attempts to ban the annual party outright, or at the very least prevent masquerading as devils and witches.”

In fact some religious groups have co-opted Halloween for their own purposes, creating their own evangelical version called Hell House to give wayward teenagers a chance to be “scared straight.”

Read more at Discovery News

Daylight Doesn't Matter: Native Trees Need Cold

Northern native trees’ early awakening in spring may depend on chilling out during a cold winter. Whereas invading plants from the south have less need for a long winter’s nap.

Biologists recently observed that trees from further north, including syrup-dribbling sugar maples, sprouted earlier if they suffered through long cold periods. The effect of chilling exceeded that of increasing day length. The complete lack of a frigid time greatly delayed the budding of new leaves by native trees.

However, more southerly species, such as walnut and locust trees, responded to increasing day length, regardless of whether or not they had rested through a cold snap. As winters warm up, these species have been moving further north and taking turf from chill-cherishing oak and beech.

“Contrary to previous assumptions, the increasing length of the day in spring plays no big role in the timing of budding,” said lead author Julia Laube of Germany’s Technische Universitaet Muenchen in a press release. “An ample ‘cold sleep’ is what plants need in order to wake up on time in the spring.”

Climate change may give an advantage to invaders from the south. Since the newcomers get an early start in the spring, they have more time to overgrow native trees. However, nature could take revenge on these southern species. A sudden cold spell can destroy the tender buds of trees that sprang for spring too soon.

Read more at Discovery News

Redwoods Record Ancient Ocean Climate

The tallest trees on the planet, the coastal redwood, trapped a record of the Pacific Ocean within their ancient wood.

Centuries of fog from the ocean left a chemical signature in the rings of the massive redwoods (Sequoia sempervirens) that was distinct from the chemicals left by rainwater. A recent study identified that difference and used it to reconstruct the climate patterns of the past 50 years. The same method could produce a Pacific Ocean weather report stretching back to the Roman empire.

“Redwoods are restricted to a very narrow strip along the coastline,” co-author Jim Johnstone said in a press release. “They’re tied to the coastline, and they’re sensitive to marine conditions, so they actually may tell you more about what’s happening over the ocean than they do about what’s happening over land.”

Coastal redwoods can live for nearly 2,000 years. However, until now, the erratic patterns of the trees’ rings limited their usefulness in reconstructing climate from the size of growth rings, a technique known as dendrochronology. Coastal redwoods may grow incomplete rings that don’t always complete the circle around the trunk. This makes it difficult to count the rings to learn the trees’ age or measure the rings to learn about the weather in each year of the trees’ lives

Instead of counting and measuring rings, a team of scientists, measured the levels of different forms of oxygen trapped in the wood. Oxygen in the air holds more of the lighter-weight form, or isotope, of oxygen, O-16, with smaller amounts of heavier O-18.

When water evaporated off of the ocean, some of the water rains back down onto the ocean, carrying the heavier O-18 molecules with it. The rain that reaches land carries more O-16.

Fog, on the other hand, evaporates from the ocean and blows directly onto the trees where it condenses and drips down to water the trees. Since fog doesn’t condense until it reaches the trees, it carries a higher percentage of O-18.

The redwoods sucked up the water from both rain and fog. The ratio of the different types of oxygen corresponded to the varying amounts of fog and rain over the years. For example, a foggy yet dry summer would result in more O-18. Similarly, variations in carbon isotopes in the redwoods reflected changes in growth related to temperature and total moisture in the environment.

Read more at Discovery News

Sensitive Dark Matter Detector Draws a Blank

A new experiment buried deep underground has proven itself to be the most sensitive dark-matter detector ever built. But the first results from the high-tech instrument have turned up empty in its search for elusive dark matter, scientists announced today (Oct. 30).

Housed 1 mile (1.6 kilometers) underground in the Black Hills of South Dakota, the Large Underground Xenon (LUX) experiment's sensitivity makes it better at seeking out dark matter than any other detectors built for that purpose, LUX officials said. Although the powerful dark matter detector has just completed its first run, LUX has not yet found conclusive evidence of the elusive substance.

"The universe's mysterious dark sector presents us with two of the most thrilling challenges in all of physics," Saul Perlmutter, of the Lawrence Berkeley National Laboratory and a winner of the 2011 Nobel Prize in physics, said in a statement. "We call it the dark sector precisely because we don't know what accounts for most of the energy and mass in the universe. Dark energy is one challenge, and as for the other, the LUX experiment's first data now take the lead in the hunt for the dark-matter component of the dark sector."

Scientists think that dark matter makes up the majority of the matter in the universe; however, it cannot be seen or touched. Astronomers detect dark matter because they have seen its gravitational effects on galaxies and stars.

By running experiments like LUX far underground, scientists hope to shield the dark-matter detector from everything but WIMPs — weakly interacting massive particles that are thought to be the leading candidates for the particles that make up dark matter.

"LUX is the quietest place verified in the world," Rick Gaitskell, a Brown University physicist, said during a seminar on the findings. "That's how far we've had to go in order to be in a position to look for these WIMPs."

LUX is particularly adept at searching for low-mass WIMPs, which are predicted by some theoretical physics models. WIMPS are extremely difficult to find because they rarely interact with ordinary matter, except through gravity, LUX officials said.

Scientists think that WIMPs can be both low-mass and high-mass, and LUX has an enhanced sensitivity to low-mass WIMPs. The dark-matter detector recently completed its first data-collecting research run.

Through the course of the approximately three-month WIMP search, scientists did not find signals of WIMPs, although previous experiments with other detectors predicted that they would.

"Three candidate WIMP events recently reported in ultracold silicon detectors, however, would have produced more than 1,600 events in LUX's much larger detector, or one every 80 minutes in the recent run," LUX officials said in a statement. "No such signals were seen."

Read more at Discovery News

Largest Dino of All Time Is Digitally Recreated

A digital reconstruction of the world’s largest known land animal, the Cretaceous dinosaur Argentinosaurus, has allowed it to take its first steps -- albeit virtually -- in over 94 million years.

The recreation, outlined in PLoS ONE, is the most anatomically detailed walking simulation so far for a dinosaur, according to the researchers. The study also provides the first ever virtual trackway for Argentinosaurus.

The skeleton used in the study shows that the plant-eating dinosaur measured at least 131 feet long. The reconstruction reveals that it lumbered along at around 5 miles per hour.

“The simulation shows a slow walking gait, which is to be expected, given that the animal weighs 80 tonnes,” lead researcher Bill Sellers from the University of Manchester’s Faculty of Life Sciences, told Discovery News. “What is interesting is how well the simulated footfall pattern matches up with typical sauropod trackways.”

For the study, Sellers and his colleagues laser scanned the huge dinosaur’s skeleton. They then used an advanced computer modeling system (Sellers has his own software called Gaitsym) that involves the equivalent of 30,000 desktop computers. It virtually recreated the dinosaur, including the sauropod’s movements.

The discovery that Argentinosaurus could walk counters prior speculation that the animal could not have done so, based on previous estimations of its size.

This latest research concludes not only that Argentinosaurus could walk, but that it was also at the top of its food chain.

“Once you hit 80 tonnes, you don’t have to worry about being eaten by predators,” Sellers explained. “We don’t know whether this animal used its long neck to graze over wide areas of low-laying vegetation or for reaching the tops of trees, but from its locomotion we know that it was a slow, steady mover.”

Argentinosaurus eggs, however, were no bigger than those of many dinosaurs and large birds. It's therefore likely that Argentinosaurus young were fairly small and would have been easy prey for other carnivorous species that lived along the Cretaceous planes of what is now Patagonia, South America.

Understanding how such past animals moved may help us to better understand modern day musculoskeletal systems.

“If you are trying to understand any body system that is shared by a range of different animals then it is often extremely useful to compare this system across different species,” Sellers explained. “Vertebrate muscles, skeletons and joints work exactly the same way in everything from fish to humans.”

He continued, “The really interesting aspect of dinosaur locomotion is that you are looking at animals that test the limits of the musculoskeletal system simply by virtue of being so big. They have to make compromises and come up with ways of coping that help us to understand the limits and compromises in the human musculoskeletal system.”

Phillip Manning is head of the Paleontology Research Group at the University of Manchester and is a research associate at the American Museum of Natural History.

Manning told Discovery News that paleontology is now undergoing a renaissance, with more interdisciplinary approaches, such as this, helping to solve long-standing questions.

“To carefully break down the key components of the locomotion of such vast animals as Argentinosaurus is allowing us greater insight to the biology and physiology of such vast organisms,” Manning said. “The diverse plethora of techniques and technology available to paleontology today is changing the way we study and interpret the fossil record.”

Read more at Discovery News