3,000 Skeletons Recovered at London Train Station Site

Archaeologists in London have begun digging up some 3,000 skeletons including those of victims of the Great Plague from a burial ground that will become a new train station, the company in charge said.

A team of 60 researchers will work in shifts six days a week over the next month at the Bedlam burial ground to remove the ancient skeletons, which will eventually be re-buried at a cemetery near London.

Crossrail, which is building a new east-west train line in London, said the dig near Liverpool Street station was being carried out on its behalf by the Museum of London's archaeology unit.

The company said in a statement that the bones would be tested to "shed light on migration patterns, diet, lifestyle and demography" of Londoners at the time.

"Archaeologists hope that tests on excavated plague victims will help understand the evolution of the plague bacteria strain," Crossrail said.

The Bedlam ground was used between 1569 and 1738 -- a period that spanned Shakespeare's plays, the Great Fire of London and numerous plague outbreaks.

The excavation is also expected to further uncover the remains of an ancient Roman road, where Crossrail said that several artifacts such as horseshoes and cremation urns have already been found.

The area was London's first municipal burial ground and was named after the nearby Bethlem Royal Hospital or "Bedlam" -- the world's oldest psychiatric institution, which has since relocated outside London.

The burial ground was used by Londoners who could not afford a church burial or who chose to be buried there for religious or political reasons.

Members of the Levellers, a 17th-century political grouping that advocated popular sovereignty and religious tolerance, are believed to be buried there.

Following excavation, constructors will build a new ticket hall for Crossrail's Liverpool Street station.

"The Bedlam burial ground spans a fascinating phase of London's history, including the transition from the Tudor-period City into cosmopolitan early-modern London," said Jay Carver, Crossrail lead archaeologist.

Read more at Discovery News

Alexander the Great-Era Treasure Found in Israeli Cave

A rare cache of jewelry and silver coins, minted during the reign of Alexander the Great, has been discovered in a stalactite filled cave in northern Israel, the Israel Antiquities Authority (IAA) announced on Monday.

The 2,300-year-old treasure was found by three members of the Israeli Caving Club who wriggled through a narrow passage at the entrance of the stalactite cave and wandered inside for several hours.

Stashed inside a niche, one of the spelunkers, Hen Zakai, spotted two ancient silver coins.

On one side of the coins was an image of Alexander the Great, while the other side portrayed an arm raised Zeus sitting on his throne.

The archaeologsts believe the coins had been minted in the late fourth century B.C. at beginning of the Hellenistic Period during the reign of Alexander the Great.

Alongside the coins, the spelunkers found the remains of a cloth pouch with three rings, four bracelets, two decorated earrings, three other earrings, probably made of silver, a small stone weight, and a clay oil lamp.

Dating from the Hellenistic period, the lamp contained some agate stones that were part of a string of beads.

“The valuables might have been hidden in the cave by local residents who fled there during the period of governmental unrest stemming from the death of Alexander,” the IAA said in a statement.

At that time, the Wars of the Diadochi broke out in Israel between Alexander the Great’s successors who fought for the control of the king’s empire after his death in 323 B.C.

“Presumably the cache was hidden in the hope of better days, but today we know that whoever buried the treasure never returned to collect it,” the IAA said.

As archaeologists of the Israel Antiquities Authority this week-end entered the cave, they discovered evidence of human habitation that occurred there over extended periods, from the Chalcolithic period 6,000 years ago to the Hellenistic period approximately 2,300 years ago.

Numerous pottery vessels were discovered in the cave and some even merged with the limestone sediments.

“The finds in the cave will allow the researchers –- archaeologists and geologists alike –- to accurately date both the archaeological finds and the process of stalactite development,” the IAA said.

The treasure trove, which promises to shed light on the lives of ordinary people in Israel during the late 4th century BC, follows another significant finding. Last month amateur scuba divers stumbled across a trove of nearly 2,000 gold coins that sat on the bottom of the Roman-era port of Caesareafor about 1,000 years.

Read more at Discovery News

The Milky Way May be 50 Percent Bigger Than Thought

A ring-like filament of stars wrapping around the Milky Way may actually belong to the galaxy itself, rippling above and below the relatively flat galactic plane. If so, that would expand the size of the known galaxy by 50 percent and raise intriguing questions about what caused the waves of stars.

Scientists used data collected by the Sloan Digital Sky Survey to reanalyze the brightness and distance of stars at the edge of the galaxy. They found that the fringe of the disk is puckered into ridges and grooves of stars, like corrugated cardboard.

“It looks to me like maybe these patterns are following the spiral structure of the Milky Way, so they may be related,” astronomer Heidi Newberg, with Rensselaer Polytechnic Institute in New York, told Discovery News.

She and colleagues suspect that a dwarf galaxy may have plunged through the disk of the Milky Way, setting off ripples, like a pebble falling into a pond.

Intruder galaxies also may have set up spiral wave patterns that later trigger star formation in the gas along waves, leading to spiral arms in galaxies.

Evidence that the so-called Monoceros Ring, located more than 65,000 light years from the center of the galaxy, actually is part of the Milky Way surprised Newberg, who was on a team that discovered the ring in 2002.

“We thought it was a tidal debris stream -- a dwarf galaxy that came in and spread itself out in this big ring. For 15 years, there’s been a controversy in the field where half the astronomers think it’s a tidal stream and half the astronomers think its something in the disk. I was in the stream camp,” Newberg said.

“What I was trying to do was find more evidence that it was streams. It took a very long time to get this result, partly because I had to change my whole my whole way of thinking. It now looks to me like it’s part of the disk,” she said.

Incorporating the ring into the map of the Milky Way expands the galaxy’s span from 100,000 light years to 150,000 light years, said astronomer Yan Xu, with the National Astronomical Observatories of China and a former visiting scientist at Rensselaer.

Light travels at 186,000 miles per second, so one light year is nearly 6 trillion miles.

Read more at Discovery News

Earth-Based Radar Unveils Venus' Mysterious Surface

These days if you look toward the west after sunset you’ll see a bright star that’s the first to appear in the sky – except it’s not a star at all, but our neighboring planet Venus. Covered in a dense layer of thick clouds, Venus not only reflects a lot of sunlight but also keeps its surface well concealed from visible-light observations.

But Venus’ clouds can be easily penetrated by radar, which was used by NASA’s Magellan spacecraft to map nearly all of its surface from orbit in the early 1990s as well as by the previous Pioneer and Soviet Venera spacecraft in the early 80s. While these missions provided incredibly detailed maps of Venus’ rugged terrain, they lack the ability to monitor for surface changes that may occur either suddenly or over short time frames — changes that could indicate ongoing geologic or weather-related processes unique to the planet.

Fortunately with the capabilities of powerful ground-based radar observatories, scientists have been able to create global maps of Venus from right here on Earth… no rockets necessary.

The image above was created by bouncing radar waves transmitted from the Arecibo Observatory in Puerto Rico off Venus and receiving their echoes at the 100-meter Green Bank Telescope in West Virginia. Such observations had been performed in 1988, 1999, 2001, and most recently in 2012, and the comparison allows researchers to hunt for clues to any surface activity.

“It is painstaking to compare radar images to search for evidence of change, but the work is ongoing,” said Bruce Campbell, Senior Scientist with the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington, D.C. ”In the meantime, combining images from this and an earlier observing period is yielding a wealth of insight about other processes that alter the surface of Venus.”

Venus appears to have a relatively young surface covered in volcanoes as well as ridged and folded terrain, but with little to no tectonic activity. It’s not yet known what, if any,  geologic processes are currently in action on the Earth-sized planet today, although there are several volcanoes that are thought to have been active in the past couple million years and there have also been indications of possible volcanic outbursts observed in Venus’ atmosphere by ESA’s Venus Express.

A paper discussing the radar observations has been accepted for publication in the journal Icarus.

From Discovery News

Dog Sniffs Out Thyroid Cancer in Human Urine

A scent-trained dog was able to identify the presence or absence of thyroid cancer in human urine samples 88.2 percent of the time, a new study concluded.

The study out of the University of Arkansas for Medical Sciences (UAMS) gathered urine samples from 34 university thyroid clinic patients before they underwent a biopsy for suspicion of thyroid cancer.

Fifteen of those biopsies came back positive for thyroid cancer, while the remaining 19 were diagnosed as benign thyroid disease.

Enter Frankie, a male German shepherd mix that had been trained to recognize the scent of cancer in thyroid tissue. Frankie's sharp nose matched 30 out of 34 samples with their pathology diagnoses.

"Frankie is the first dog trained to differentiate benign thyroid disease from thyroid cancer by smelling a person’s urine," said study co-author Arny Ferrando, PhD at UAMS, in a release.

The study's senior investigator, Donald Bodenner, M.D., PhD, and chief of endocrine oncology at UAMS, said Frankie was only slightly less accurate than a standard thyroid biopsy with a needle. The dog's results offer the possibility of a cheaper, less invasive approach to diagnosis of the illness.

"Current diagnostic procedures for thyroid cancer often yield uncertain results, leading to recurrent medical procedures and a large number of thyroid surgeries performed unnecessarily," Bodenner explained. "Scent-trained canines could be used by physicians to detect the presence of thyroid cancer at an early stage and to avoid surgery when unwarranted."

Bodenner is not yet using canines in formal diagnoses outside of the study and said the next step will be to collaborate with Auburn University's College of Veterinary Medicine on an expansion of the scent-training program. The veterinary center plans to train two of its bomb-sniffing dogs to learn how to sniff out thyroid cancer, using samples from UAMS patients.

From Discovery News

Sheep Use Their Brains to Save Water

Sheep can reduce water loss by using a heat exchange system in their brain to cool down their blood, new research suggests.

The animals can save up to 80 percent of their daily water intake by using this system, said comparative physiologist, Dr Shane Maloney from the University of Western Australia.

Previous research has shown that sheep cool blood flowing into their brains using a structure called a carotid rete at the base of the brain. In this structure, the artery with blood flowing towards the brain divides into many fine blood vessels about 50 microns in diameter.

Heat in warm arterial blood can transfer out of these fine arteries into cooler venous blood that also passes by the rete. The venous blood, traveling down the body, has been cooled by evaporation in the sheep's nose.

The common wisdom has been that this cooling system is used to protect the sheep's brain from overheating. But a discovery in a study of South African black wildebeest in the 1990s didn't fit this theory.

While data loggers on the wildebeest showed that brain cooling was often switched on through the day, it was switched off when the animals were at their hottest when being chased by researchers in helicopters.

The fact they were hot but not using brain cooling led to the idea that brain cooling serves another purpose than protecting the brain.

An alternative theory suggests the system is actually a water-saving mechanism that works by cooling the hypothalamus, the body's thermostat, which sits at the base of the brain. When the hypothalamus is hot it triggers panting and sweating, which helps the animal to lose heat through evaporation.

"By switching on this brain cooling mechanism you lower the hypothalamic temperature and therefore you don't stimulate water use for thermoregulation (panting and sweating)," said Maloney.

Hot sheep

To test this hypothesis, Maloney and colleagues studied nine sheep, which naturally varied in the percentage of time they spent brain cooling during the day. When the hypothalamus is hot it triggers panting and sweating, which helps the animal to lose heat through evaporation.

"It was a bit like a Perth summer," said Maloney.

The sheep were deprived of water for the last five days (Maloney said sheep are known to go for a week without water). Throughout the experiment the researchers measured water loss, and brain and body temperatures every five minutes.

Their findings, reported in a recent issue of PLOS ONE, showed the longer an animal went without water, the more time it spent with its brain cooling system switched on.

This led to a greater difference between the animal's body and brain temperatures, and decreased the amount of water lost.

This is the first study of its kind to lend support to the hypothesis that brain cooling saves water, said Maloney.

He and colleagues calculate that a 50-kilogram sheep can save 2.6 liters of water a day, which is about 60 percent of its daily water intake, by using this system for 50 percent of the day.

For an animal using the system 80 percent of the day, this amount would increase to 3.54 liters a day, or 80 percent of normal water use.

Need for calm

Maloney said there is some evidence that the more stressed an animal becomes, the less amount of brain cooling it uses. Brain cooling is switched off by the sympathetic nervous system which in turn is triggered by stress.

This explains why the wildebeest in the 1990s South African study had their system switched off even though they were hot -- they were stressed due to being chased by helicopters. In this situation it was more important for them to lose heat than to save water.

"Whereas if you've got a nice calm docile animal ... they don't switch on the sympathetic nervous system, selective brain cooling is activated so they lower brain temperature and don't pant and sweat."

Read more at Discovery News

'Habitable' Super-Earth Might Exist After All

Despite having discovered nearly 2,000 alien worlds beyond our solar system, the profound search for exoplanets — a quest focused on finding a true Earth analog — is still in its infancy. It is therefore not surprising that some exoplanet discoveries aren’t discoveries at all; they are in fact just noise in astronomical data sets.

But when disproving the existence of extrasolar planets that have some characteristics similar to Earth, we need to take more care during the analyses of these data, argue astronomers from Queen Mary, University of London and the University of Hertfordshire.

In a paper published by the journal Science last week, the researchers focus on the first exoplanet discovered to orbit a nearby star within its habitable zone.

Revealed in 2009, Gliese 581d hit the headlines as a “super-Earth” that had the potential to support liquid water on its possibly rocky surface. With a mass of around 7 times that of Earth, Gliese 581d would be twice as big with a surface gravity around twice that of Earth. Though extreme, it’s not such a stretch of the imagination that such a world, if it is proven to possess an atmosphere and liquid ocean, that life could take hold.

And the hunt for life-giving alien worlds is, of course, the central motivation for exoplanetary studies.

But the exoplanet signal has been called into doubt.

Gliese 581d’s star, Gliese 581, is a small red dwarf around 20 light-years away. Red dwarfs are known to be tempestuous little stars, often generating violent flaring outbursts and peppered in dark features called starspots. To detect the exoplanet, astronomers measured the very slight frequency shift (Doppler shift) of light from the star — as the world orbits, it exerts a tiny gravitational “tug”, causing the star to wobble. When this periodic wobble is detected, through an astronomical technique known as the “radial velocity method,” a planet may be revealed.

Last year, however, in a publication headed by astronomers at The Pennsylvania State University, astronomers pointed to the star’s activity as an interfering factor that may have imitated the signal from an orbiting planet when in fact, it was just noisy data.

But this conclusion was premature, argues Guillem Anglada-Escudé, of Queen Mary, saying that “one needs to be more careful with these kind of claims.”

“The existence, or not, of GJ 581d is significant because it was the first Earth-like planet discovered in the ‘Goldilocks’-zone around another star and it is a benchmark case for the Doppler technique,” said Anglada-Escudé in a university press release. “There are always discussions among scientists about the ways we interpret data but I’m confident that GJ 581d has been in orbit around Gliese 581 all along. In any case, the strength of their statement was way too strong. If the way to treat the data had been right, then some planet search projects at several ground-based observatories would need to be significantly revised as they are all aiming to detect even smaller planets.”

The upshot is that this new paper challenges the statistical technique used in 2014 to account for the signal being stellar noise — focusing around the presence of starspots in Gliese 581′s photosphere.

Read more at Discovery News

We Need to Cast a Wide Net in Search for Alien Life

The hunt for signs of life on planets beyond our solar system should cast as wide a net as possible, some researchers stress.

Scientists scanning the atmospheres of exoplanets for gases produced by alien life should look for more than just oxygen, methane and the other familiar biosignatures that swirl about in Earth's air, Sara Seager and William Bain, both of MIT, wrote in a review article published on March 6 in the journal Science Advances.

"We know there will not be huge numbers of accessible planets," Seager told Space.com via email. "We want to make sure we do not miss any signatures, by trying our best to think outside the box. Oxygen is a great biosignature gas for Earth, but what are the chances it will be present on an exoplanet?"

To date, scientists have discovered more than 1,800 alien planets, most of which are very different from the worlds in our solar system.

"A specific, astonishing finding is that the most common type of planet in our galaxy are those with sizes between those of Earth and Neptune — a new class of planet that is neither terrestrial nor giant and one without an accepted theory for its formation," Seager and Bain wrote.

The diversity of exoplanets reinforces the very real possibility that alien life may be quite different from life on Earth, even if it inhabits a rocky world like our own. For example, what might live on "exo-Earths" whose atmospheres are dominated by molecular hydrogen instead of nitrogen and oxygen, as Earth's is?

"Although not yet observed, such planets are theoretically anticipated," Seager and Bains wrote.

Based on that reasoning, the researchers advocate an open-minded approach that would first identify "all viable biosignature gases, through a systematic, exhaustive study both from the view of molecules (there is no shortage) and of planetary environments and where the candidate biosignature gas molecules would accumulate and survive," they wrote.

"The near-term goal is to understand which molecules could be biosignature gases in atmospheres of exoplanets; a systematic table of chemicals made by life will give a starting point for predicting which molecules are stable, volatile and detectable remotely by space telescopes," Seager and Bains added.

Such a challenging project would likely take years to complete, Seager told Space.com. But researchers can spare the time because a systematic search for signs of life on alien worlds is probably at least a decade away, she and Bains wrote.

Scientists have already begun probing exoplanet atmospheres, using instruments such as the European Southern Observatory's Very Large Telescope in Chile.

And the effort will kick into higher gear soon, with the launch of NASA's Transiting Exoplanet Survey Satellite (TESS) in 2017 and the agency's James Webb Space Telescope (JWST) in 2018. TESS should find a number of nearby rocky planets whose atmospheres JWST can investigate. (Most exoplanets found to date, including those found by NASA's prolific Kepler space telescope, are too far away for such follow-up study.)

Massive ground-based telescopes, such as the Giant Magellan Telescope, Thirty Meter Telescope and European Extremely Large Telescope — which boast light-collecting surfaces 80 feet (24 meters), 98 feet (30 m) and 128 feet (39 m) wide, respectively — will boost the search further when they come online in the mid-2020s.

But Seager and many other experts say that the biosignature search really needs a space telescope with a mirror in the 33- to 39-foot (10 to 12 m) range — something like the proposed Advanced Technology Large-Aperture Space Telescope, or ATLAST.

Such an instrument could potentially analyze enough exoplanet atmospheres for researchers to do some number crunching. And that's important; the biosignature hunt will probably center on probabilistic inference because a slam-dunk detection will be difficult, if not impossible, to make, Seager and Bains wrote.

Read more at Discovery News

'Extinct' Bird Not Seen Since 1941 Suddenly Reappears

A conservation research team in Myanmar got a local call from the distant past when a bird long thought to be extinct suddenly chirped and begged to differ. And with that the Myanmar Jerdon's babbler (Chrysomma altirostre) was back in the birding phone book (for those who remember those big blocky books with phone numbers in them).

While surveying grasslands near the town of Myitkyo in May 2014, a team comprised of researchers from the Wildlife Conservation Society, Myanmar's Nature and Wildlife Conservation Division, and the National University of Singapore (NUS) heard the call of the long-lost babbler.

The team quickly played back a recording of the call, and soon an adult Jerdon's babbler, a bird not seen in Myanmar since 1941, came into view.

After that first encounter, it got even better. It was Jerdon's babblers aplenty, as over the next two days the team found the suddenly conspicuous birds in multiple locations near the first call.

A Jerdon's babbler is small and brown -- about the size of an ordinary house sparrow. It was first described in 1862 and was a common sight in Myanmar at the start of the 20th century, in wide-ranging grasslands around the Yangon region that were lost over time to agriculture and community development.

"The degradation of these vast grasslands had led many to consider this subspecies of Jerdon’s babbler extinct," explained Colin Poole, director of the Wildlife Conservation Society's efforts in Singapore. "This discovery not only proves that the species still exists in Myanmar but that the habitat can still be found as well."

The re-discovered Myanmar babbler is at this point considered one of three Jerdon's babbler subspecies found in river basins in South Asia (Terai and Sind are the other subspecies). But DNA samples and audio recordings obtained from the newfound birds should help researchers determine whether or not the Myanmar Jerdon's babbler should be a full species in its own right.

"Our sound recordings indicate that there may be pronounced bio-acoustic differences between the Myanmar subspecies and those further west, and genetic data may well confirm the distinctness of the Myanmar population," noted Frank Rheindt, an assistant professor in the NUS Department of Biological Sciences.

Read more at Discovery News

Far Flung Star Cluster Found at Milky Way's Edge

Astronomers in Brazil have discovered a cluster of stars forming at the edge of the Milky Way, according to a press release from the Royal Astronomical Society.

This is unusual because it was believed that stars generally take form closer to the center of our spiral-shaped galaxy, rather than from its swirling, spiral arms, which are thousands of light-years away. These two clusters of stars — named Camargo 438 and 439 — were seen in a cloud at the galaxy’s outskirts.

Denilso Camargo, an astronomer at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil, led a team that analyzed data from NASA’s orbiting Wide-Field Infrared Survey Explorer (WISE) observatory. They zeroed in on dense clumps of gas in so-called giant molecular clouds(GMCs) that are known to generate stars. GMCs are mainly located in the inner part of the galactic disc.

The new star clusters lie about 16,000 light-years away from the main disk of the Milky Way galaxy. How did they form there? The scientists aren’t yet sure but Camargo theorizes that one of two scenarios could have led to the stars’ formation.

In the first scenario, called the “chimney model,” supernovas could have flung the gas and dust that formed the cloud out of the Milky Way. Another explanation is the material could have drifted in from outside the galaxy.

“Our work shows that the space around the Galaxy is a lot less empty that we thought,” said Camargo. “The new clusters of stars are truly exotic.”

Camargo’s team published their results in the journal Monthly Notices of the Royal Astronomical Society.

From Discovery News