Friday, September 30, 2011

Methodology Applied to Historical Walls May Explain Why Moss Gathers and How Paint Blackens

For the correct restoration of deteriorated works of cultural heritage, it helps to know what causes the degradation in the first place. There are studies that characterise these types of damage in detail, but that rarely touch on the origin and development of the deterioration. Chemist Maite Maguregui has come up with an analytical methodology with the intention of filling this need: considering the material of origin of the historical heritage and the product that substituted over time (the decay product), in order to appropriately understand the development of the degradation process.

She presented her PhD thesis at the University of the Basque Country (UPV/EHU), with the title, A new diagnosis protocol to assess the impact of environmental stressors on historical bricks, mortars and wall paintings.

Ms Maguregui characterised the deterioration caused by infiltrating water, atmospheric acid gases and microorganisms, and observed that human intervention has had much to do with all this. Specifically, she applied this methodology to bricks, mortars and wall paintings; amongst others the paintings in dwellings of old Pompeii. Ms Maguregui and her colleagues have published an article in Analytical Chemistry based precisely on the work undertaken in the Roman city and entitled Thermodynamic and spectroscopic speciation to explain the blackening process of hematite formed by atmospheric SO2 impact: the case of Marcus Lucretius House (Pompeii).

Diversity of techniques

This methodology included different analyses. To begin with, use was made of non-invasive spectroscopic techniques in order to characterise both the original compounds and the decay products. Moreover, microdestructive techniques were applied to the quantification of soluble salts, given that the considerable presence of these causes damage to works of cultural and historical heritage. Chemometry was employed for treatment of data and, in order to understand the development of the process of deterioration, chemico-thermodynamic models were used. In the final part, Raman spectroscopy and depth profiling were used, with the aim of determining the distribution of the components, both of the original compound and of the decay products.

With this analysis, it was seen that sulphur dioxide and oxides of nitrogen are amongst the principal causes of deterioration -- compounds that are found in industry, automotion, food industry, and so on. Thus, it is human activity that is responsible for the deterioration of cultural and historical heritage.

Also thanks to this analysis, Ms Maguregui concluded that environmental factors do not negatively affect heritage works in an isolated manner, but each item can deteriorate in diverse ways. In Pompeii, sulphur dioxide had damaged plaster, on which, in turn, moss grew. It was thus concluded in the thesis that there may be a nexus between these two phenomena. In fact, other researchers have already mentioned that gypsum could be a good nutrient for colonising microorganisms. Thus, the sulphation caused by sulphur dioxide on the plaster attracts microorganisms, which is why moss grows and accumulates.

Acceleration of the process

The data gathered with the new methodology enabled the researcher to make hypotheses about how the process takes place and what mechanisms take part in each case. But, besides explaining this at a theoretical level, she has validated it. She copied the supposed process of deterioration in some of the cases, applying it experimentally using a series of techniques that accelerated the development of the process, a series which the researcher, herself, designed.

Concretely Ms Maguregui carried out an experiment on the wall paintings of the Marcus Lucretius House in Pompeii. The zones that originally contained red haematites were blackened, as these had been substituted by magnetite and iron (III) sulphate nonahydrate. According to the researcher, both decay products would have appeared as a result of sulphur dioxide; a hypothesis that she verified thanks to the experimentation accelerating the process. As a result these zones of the wall paintings had blackened due to effect of human activity on the environment.

Science Daily. 2011. "Methodology Applied to Historical Walls May Explain Why Moss Gathers and How Paint Blackens". Science Daily. Posted: September 13, 2011. Available online:

Thursday, September 29, 2011

Pictish beast intrigues Highland archaeologists

A Pictish symbol stone built into the wall of a Highland farm building has been recorded by archaeologists.

The markings show a beast, crescent, comb and mirror.

Archaeologist Cait McCullagh said it was a mystery how it had taken until this year for the stone to be officially recorded.

She said it also suggested that more Pictish stones have still to be documented on the Black Isle where the beast was recorded.

Ms McCullagh, the co-founder and director of Archaeology for Communities in the Highlands (Arch), said the symbol stones probably dated from the 5th to 7th centuries AD.

She said it was unusual to find such carvings on the north side of the Moray Firth.

A lack of weathering on the Pictish beast may suggest the stone had been kept inside, or had been buried, for a long period before it was placed in the wall of the byre.

Isobel Henderson, an expert in the field of early medieval sculpture, came across the Pictish beast stone earlier this year and alerted Highland Council archaeologists.

Easter Ross-based Ms McCullagh was also notified and she confirmed the markings as Pictish.

She also went on to identify a Pictish symbol stone in the wall of a nearby farmhouse with markings thought to represent goose feathers, or fish scales. Harling obscures most the carving.

'A mystery'

Both stones are on private properties built in the 19th Century and owned by the same family for about 50 years until two years ago.

Ms McCullagh said the relics were never mentioned during a recent local heritage project that had asked people to suggest sites of archaeological and historical interest.

The Pictish beast and goose, or fish, markings have been recorded by Highland Council's Historic Environment Record.

Ms McCullagh said: "It is a mystery why it has taken so long for the stones to come to our attention.

"It is also exciting to think that there are maybe more still to be found.

"We are always encouraging people to put their Pictish specs on and look out for stones in church yards and dykes."

The Picts lived in north and east Scotland in the 3rd to 9th centuries AD.

Few written records of the people survive.

According to Highland Council, inscriptions suggest that the Picts spoke a language closely related to both Welsh and Gaelic.

McKenzie, Steven. 2011. "Pictish beast intrigues Highland archaeologists". BBC News. Posted: September 14, 2011. Available online:

Wednesday, September 28, 2011

Urban Population Explosion (Infographic)

science education


Toro, Ross. 2011. "Urban Population Explosion (Infographic)". Live Science. Posted: September 13, 2011. Available online:

Tuesday, September 27, 2011

New Technique for Dating Silk

Strand for strand no fabric can compare to the luxurious feel, luminosity and sheen of pure silk. Since millennia, the Chinese have been unraveling the cocoons of the silk worm (Bombyx mori) and weaving the fibers into sumptuous garments, hangings, carpets, tapestries and even artworks of painted silk.

Now, for the first time, scientists at the Smithsonian's Museum Conservation Institute have developed a fast and reliable method to date silk. This new technique, which is based on capillary electrophoresis mass spectrometry, has great potential to improve the authentication and dating of the priceless silk artifacts held in museum and other collections around the world.

The new method uses the natural deterioration of the silk's amino acids--a process known as racemization--to determine its age. As time goes by, the abundance of the L-amino acids used in the creation of the silk protein decreases while the abundance of D-amino acids associated with the silk's deterioration increases. Measuring this ever-changing ratio between the two types of amino acids can reveal the age of a silk sample.

Archaeologists and forensic anthropologists have used this process for decades to date bone, shells and teeth, but the techniques used required sizeable samples, which for precious silk objects are almost impossible to obtain.

"Many things an animal makes are protein based, such as skin and hair. Proteins are made of amino acids," explains Smithsonian research scientist Mehdi Moini, chief author of a recent paper in the journal Analytical Chemistry announcing the new dating method.

"Living creatures build protein by using specific amino acids known commonly as left-handed [L] amino acids. Once an animal dies it can no longer replace the tissues containing left-handed amino acids and the clock starts. As L- changes to D-amino acids [right handed], the protein begins to degrade," Moini explains.

Measuring this ever-changing ratio between left-handed and right-handed (D) amino acids can be used as a scientific clock by which a silk's age can be estimated. In controlled environments such as museum storage, the decomposition process of silk is relatively uniform, rendering D/L measurement more reliable.

The Smithsonian Museum Conservation Institute team used fiber samples taken from a series of well-dated silk artifacts to create a chart of left-hand and right-handed amino-acid calibration ratios against which other silks fabrics can be dated.

Those items included new silk fibers; a silk textile from the Warring States Period, China (475-221 B.C.) from the Metropolitan Museum of Art in New York City; a silk tapestry (1540s) from the Fontainebleau Series, Kunsthistorisches Museum, Vienna, Austria; a silk textile from Istanbul (1551-1599) from the Textile Museum, Washington, D.C.; a man's suit coat (1740) from the Museum of the City of New York; and a silk Mexican War flag (1845-1846) from the Smithsonian's National Museum of American History.

Previously, the scientists write, dating silk has been largely been a speculative endeavor that has mostly relied on the historical knowledge of a silk piece, as well as its physical and chemical characteristics.

The new technique takes about 20 minutes, and requires the destruction of about 100 microgram of silk fiber, making it preferable over C14 (carbon 14) dating, which requires the destruction of so much material that it is prohibitive for most fine silk items.

Science Daily. 2011. "New Technique for Dating Silk". Science Daily. Posted: September 22, 2011. Available online:

Monday, September 26, 2011

Dating Stone Tools

Q. How can scientists accurately date when stone tools were made, like those found at Lake Turkana in Kenya?

A. “An artifact like a tool made from flint is usually not dated directly but instead according to the age of the sediment layers it is found in,” said Dennis V. Kent, a research scientist at the Lamont-Doherty Earth Observatory of Columbia University.

Radiocarbon dating is widely used to date materials like charcoal from hearths and carbonate in snail shells, Dr. Kent said, but it is limited to about the last 50,000 years because of the short half-life of carbon 14. For older sediments, techniques include tephrochronology (involving potassium) and magnetostratigraphy (involving iron).

In tephrochronology, layers of volcanic ash, tephra, often contain potassium-bearing minerals whose crystallization age can be determined, even going back billions of years. But the infrequency of volcanic eruptions may make it hard to date intervening sediments.

These sediments, however, are likely to contain traces of iron-bearing minerals like magnetite, which act like compasses. Their magnetic orientation is preserved when they are encased, and there has been a well-dated series of reversals of the earth’s magnetic polarity.

The sediment around the Turkana tools was deposited soon after a reversal that occurred 1.778 million years ago, Dr. Kent said, thus helping establish an estimated age for the tools: 1.76 million years.

Ray, C. Claiborne. 2011. "Dating Stone Tools". The New York Times. Posted: September 12, 2011. Available online:

Sunday, September 25, 2011

Google Earth reveals Nazca-like structures in Arabia

Google continues to allow us to virtually go where no archaeologist has gone before. The latest finds, in the Arabian peninsula, are of spectacular stone structures that rival the Nazca lines of southern Peru in their intricacy.

The ruins are known to local Bedouin groups as "the works of the old men", and were first spotted from the air in 1927 by Percy Maitland, a lieutenant in the British Royal Air Force. But their full extent became apparent only when David Kennedy at the University of Western Australia, Perth, clicked onto Google Earth.

Kennedy says that many countries in the Middle East will not provide aerial photographs or permit flights for archaeological research, so Google Earth provides the only way to analyse the region.

Earlier this year, he identified almost 2000 potential archaeological sites in Saudi Arabia from his office chair using Google Earth's satellite images. Expanding his virtual exploration to cover the entire Arabian peninsula he has now found over 2000 "kites" – stone structures with a roughly circular head and tails hundreds of metres long. Thought to be animal traps, the tails may have funnelled in gazelle and oryx, leaving them stuck in the head.

Wheels between 20 and 70 metres across, thought to have a spiritual purpose, pepper the desert too. Similar structures in more accessible Yemen are around 9000 years old, says Kennedy.

David Thomas at La Trobe University in Melbourne, Australia, is also an armchair archaeologist. In 2008, he used Google Earth to find 463 potential sites in the Registan desert of Afghanistan. "Google Earth has a policy of no censorship, so you can get access everywhere," he says.

Zukerman, Wendy. 2011. "Google Earth reveals Nazca-like structures in Arabia ". New Scientist. Posted: September 20, 2011. Available online:

Saturday, September 24, 2011

Alaskan Archaeologists Find Ancient Artefacts

A team from the University of Alaska Museum of the North expected to find more boulders etched with petroglyphs during an expedition to further explore the remains of three prehistoric lake-front dwellings in Northwest Alaska’s Noatak National Preserve this summer.

However, when archaeologist Scott Shirar and members of his team began small-scale excavations at two of the sites, they made a fascinating new discovery: four decorated clay disks that appear to be the first of their kind found in Alaska.

“The first one looks like a little stone that had some scratch marks on it,” said Shirar, a research archaeologist at the University of Alaska Museum of the North. “We got really excited when we found the second one with the drilled hole and the more complicated etchings on it. That’s when we realised we had something unique.”

After discussion with colleagues and searching for references in the archaeological record, Shirar came to the conclusion that the disks appear to be a new artefact type for Alaska. He added, “We only opened up a really small amount of ground at the site, so the fact that we found four of these artefacts indicates there are probably more and that something really significant is happening.”

While prehistoric rock art is common in some regions, such as the American Southwest, it is exceptionally rare in Interior and Northern Alaska. Archaeologists working in the 1960s and 70s found the boulders at three different lake-front sites in what is now the Noatak National Preserve.

The rock art remained on location, undocumented for almost 40 years until this summer, when a team from the UA Museum of the North and the National Park Service assembled to create a permanent record at two of the sites.

Mareca Guthrie, fine arts collection manager at the University of Alaska Museum of the North, joined the expedition to make sketches and take tracings of the boulders. At first, she was just excited for an opportunity to get out of the basement of the museum for a week, but she quickly developed an appreciation for the people who had lived there.

It felt so intimate to be looking through someone else’s things, knowing that they sat in the same spot and saw the same view of the mountains. When I started getting tired of the mixed nuts I brought for lunch, I thought, ‘Did the kids complain when they ate caribou day after day or were they thankful to have it?’” she said. “I became so hungry to know more about them, I’m afraid I may have driven the archaeologists a little crazy with my questions.”

The team visited the site to both document the rock art and also excavate subterranean house pits to locate samples that could be used for radiocarbon dating, such as animal bones, charcoal or other organic matter in order to get a better idea of when people lived there.

Archaeologists use the term rock art to describe any human-made marks on natural stone. Petroglyphs are pictures created by picking, carving or abrading the surface of a rock.

Shirar said the precise meaning of these petroglyphs, as well as the designs on the clay disks, is still unknown, but their value is clear.

“These objects and places clearly had special significance to their makers. These finds offer an especially tangible reminder of the rich spiritual and intellectual lives they led.”

Past Horizons. 2011. "Alaskan Archaeologists Find Ancient Artefacts". Past Horizons. Posted: September , 2011. Available online:

Friday, September 23, 2011

Ancient Mediterranean Water Supply Networks Revived

Years of drought had dried up the ancient water supply networks existing around the Mediterranean Rim. However, with rainfall returning over the past 5 years, the hydraulic heritage has come to life again. The names of the tunnels that carry the revived streams -khettaras in Morocco, foggaras in Algeria or qanâts in Iran- evoke the trickling sounds of water. These underground infiltration galleries are the most characteristic and original illustration of local communities' recovery of ancestral schemes. As IRD researchers and their partners1 show, these water mines in the middle of the desert, most of which had been abandoned, have now been restored by oasis inhabitants.

These communities are now reinvesting in the maintenance of khettaras and in agriculture, especially young people returning to rural environments after experiencing unemployment in towns and cities. This is a risk owing to the uncertainties of climate, but fully assumed to revive collective action and to reappropriate the rules governing water-supply access, indeed in anticipation of possible new shortages in the years to come.

The ancestral hydraulic heritage which exists all around the Mediterranean Basin is finding renewed life. Over the past five years, the return of water is bringing back the old water supply amenities to their former status. An IRD research team and its partners1 have shown that the local communities are reinvesting these networks, abandoned during several years of drought.

The most typical, original and sophisticated examples of this revival are the underground2 infiltration galleries, tunnels known since Antiquity as khettaras in Morocco, qanât in Iran, foggaras in Algeria. These water mines are the result of an traditional technology, developed on a grand scale from the XIIth Century in North-West Africa to create artificial oases in the Sahara.

High-level technical know-how behind centuries-old schemes

The tunnels serve to conduct water from the groundwater body. The principle used for construction testifies to considerable knowledge and sophisticated technical mastery. It consists in digging into a hillside to create an underground conduit, far enough to meet a shallow aquifer. Set with a low downstream gradient, the conduit allows water to descend by gravity flow, with almost constant discharge, to emerge at the foot of the hill.

Observed from the ground surface, only a line of small characteristic cones of earth over several kilometres tells of the existence of such engineering works beneath our feet. They are the spoil removal shafts which mark the trace of the tunnel, about 30m away, and are used as access points for maintenance.

The example of Morocco

Length of the tunnels can range from 5 to 20 km for a height of 2 to 4m but scarcely 50cm wide. One example is in Tafilalet province of Morocco, in the Meknès area, where the khettaras have been better preserved. The research team focused their investigations especially on these. A total of 450 have been counted in this area. These conduits were dug from the end of the XVIIIth or early XIXth Century until 1950 and enabled a population of about 600 000, 75% of them living mainly from agriculture, to develop in this extensive area at the foot of the Atlas, hemmed in between the mountain and the Sahara.

Tunnel renovation

Modernization of public water networks during the second half of the past century, notably with dam construction, and the surge in private drilling have left the khettaras weakened. These modern networks have been superimposed on the traditional works, on the means of reinforcement or competition, and a great number of infiltration galleries were taken out of service. Then the periods of severe drought which hit in the 1970s and again from 1995 to 2005 in their turn dried up the khettaras. Five years ago, only a few dozen tunnels were still permanently in operation.

However, regular abundant rain has returned, since May 2006. The groundwater resource again feeds the catchment area upstream of some of the galleries which were partially or completely abandoned. The local communities then undertook to renovate them. In five years, at Jorf, in the west of Tafilalet, nearly 50 conduits have been put back into working order thanks to community initiatives. The local and regional water and political authorities are now also working towards the same objective and putting forward a rehabilitation scheme for khettaras.

This new boost for the communities' hydraulic heritage gives them the opportunity to reinvest in oasis-based agriculture, in particular involving young people returning from towns and cities mainly due to unemployment encountered there. Only recently, many young people started to come back to the oases to take on the restoration and maintenance of khettaras.

Like the communities living in the oases, the populations around the Mediterranean Rim are renovating the old water supply networks, in a similar way to those in the Moroccan High-Atlas, the Alps, Pyrenees or again in the mountains of Lebanon who are again injecting new life into the impressive terraced landscapes they have sculpted over the past centuries.

An uncertainty nevertheless remains: is the return of the water sustainable? A point difficult to ascertain according to the scientists. But this is where these rural societies are putting their stakes. To avoid any further individual groundwater extraction by unverifiable pumping, they are relaunching collective action to establish a new level of justice for access to water supplies… with the looming prospect of a possible new water shortage in the coming years.

Science Daily. 2011. "Ancient Mediterranean Water Supply Networks Revived". Science Daily. Posted: September 9, 2011. Available online:

Thursday, September 22, 2011

Australopithecus sediba paved the way for Homo species, new studies suggest

Fossils from South Africa display unique combination of modern features

Researchers have revealed new details about the brain, pelvis, hands and feet of Australopithecus sediba, a primitive hominin that existed around the same time early Homo species first began to appear on Earth. The new Au. sediba findings make it clear that this ancient relative displayed both primitive characteristics as well as more modern, human-like traits. And due to this "mosaic" nature of the hominin's features, researchers are now suggesting that Au. sediba is the best candidate for an ancestor to the Homo genus.

The discoveries are casting doubt on some long-standing theories about human evolution, including the notion that early human pelvises evolved in response to larger brain sizes. And there is also some new evidence suggesting that Au. sediba may have been a tool-maker.

These new findings, which include the most complete hand ever described in an early hominin, one of the more complete pelvises ever discovered and brand new pieces of the foot and ankle, are detailed in five separate studies. The Au. sediba research also boasts a high-resolution scan of an early hominin's cranium along with work that refines the date of this early hominin site in Malapa, South Africa, to nearly 2.0 million years ago, close to the emergence of Homo.

The five studies appear in the 9 September issue of the journal Science, which is published by AAAS, the international nonprofit science society.

Lee Berger, the project leader from the University of the Witwatersrand in Johannesburg, South Africa, explains what these new findings mean for modern humans. "The many advanced features found in the brain and body, along with the earlier date, make it possibly the best candidate ancestor for our genus—the genus Homo—more so than previous discoveries, such as Homo habilis."

The age of these Au. sediba fossils has been constrained to about 1.977 million years, which predates the earliest appearances of Homo-specific traits in the fossil record. Until now, fossils dated to 1.90 million years ago—and mostly attributed to Homo habilis and Homo rudolfensis—have been considered ancestral to Homo erectus, the earliest undisputed human ancestor. But, the older age of these Au. sediba fossils raises the possibility of a separate, older lineage from which Homo erectus may have evolved.

"Science is pleased to be publishing these papers, which add important new information regarding this species, who lived during an important time in human evolution and was first described in the 9 April 2010 issue," according to Brooks Hanson, deputy editor of physical sciences. "Well-preserved and complete early human fossils are so rare, and Au. sediba now provides a detailed look at some key parts of the anatomy, such as the hand and foot which are rarely well-preserved."

The caves of Malapa, nearly 30 miles northwest of Johannesburg, have provided a rich assemblage of early hominin fossils over the years. They are part of the Cradle of Humankind, which has been recognized as a World Heritage Site and set aside for its physical and cultural significance. Last year, Berger and colleagues announced the discovery of the remains of a juvenile male (MH-1) and an adult female (MH-2) Au. sediba that were found together in one of these caves

Since the fossils are too old to be dated themselves, researchers turned to the calcified sediments that have kept the fossils so well-preserved. The fossils hadn't moved since they were cemented into place, and researchers were able to identify flowstones above and below them. So, Robyn Pickering from the University of Melbourne in Victoria, Australia, and colleagues used advanced uranium-lead dating techniques and something called palaeo-magnetic dating, which measures how many times the Earth's magnetic field has reversed, on the surrounding rocks.

"This allowed us to narrow the deposition of the Au. sediba-bearing deposits to one of these short geomagnetic field events, the Pre-Olduvai event at about 1.977 million years ago," wrote Pickering.

The old age of these fossils somewhat surprised the researchers, given some of the apparently Homo-like features that Au. sediba was already displaying at the time.

Kristian Carlson from the University of the Witwatersrand and colleagues took a look at the partial skull of MH-1 and made an endocast, or a detailed scan, of the space where the juvenile's brain would have been.

"The actual brain residing within a cranium does not fossilize," said Carlson. "Rather, by studying the impressions on the inside of a cranium, palaeontologists have an opportunity to estimate what the surface of a brain may have looked like. By quantifying how much volume is contained within a cranium, palaeontologists can estimate the size of a brain."

According to researchers, the young australopith would have been around 10 to 13 years old, in human developmental terms, at the time of his death.

"The exceptionally well-preserved cranium of MH-1 was scanned at the European Synchrotron Radiation Facility, revealing internal anatomy with the highest achievable precision and contrast," continued Carlson. "The European Synchrotron Radiation Facility is the most powerful installation worldwide for scanning fossils, setting the standard for what can be achieved during non-destructive studies of internal structures of fossils."

The researchers found that the brain of the juvenile was human-like in shape, but still much smaller than the brains seen in Homo species. The orbitofrontal region of the brain, directly behind the eyes, shows some signs of neural reorganization, which perhaps indicates a rewiring toward a more human-like frontal lobe, according to the researchers. Carlson's results cast doubt upon the long-standing theory of gradual brain enlargement during the transition from Australopithecus to Homo. Instead, their findings corroborate the alternative hypothesis which proposes that a reorganization of the neurons in the orbitofrontal region allowed Au. sediba to evolve while keeping its smaller cranium intact.

A separate study of the partial pelvis of MH-2 echoes that sentiment. Job Kibii from the University of the Witwatersrand and colleagues say that Homo pelvises could not have evolved in response to their expanding cranial capacity. In fact, Au. sediba's pelvis was already developing modern, Homo-like features when their brains and skulls were still small.

"It's clear there could be two things driving the evolution of the pelvis in our Homo lineage," said Steven Churchill from Duke University in Durham, North Carolina, a co-author of the paper. "One is bipedal locomotion. Between six and two million years ago, we begin to see a lot of it. The other thing is our big brains."

"Our brains have to pass through the pelvis, so accommodations must be made," continued Churchill. "What's cool about sediba is their pelvises are already different from other australopiths, and yet they're still small-brained… It's hard to imagine that there's no change in locomotion behind all this."

And like most other aspects of Au. sediba, the hominin's hands and feet display an interesting mix of both primitive and modern features.

The wrist and hand of MH-2 are only missing a few bones, making them the most complete hand fossils for an early hominin on record. Tracy Kivell from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues analyzed the female Au. sediba's hand and found that there was a strong flexor apparatus, which hints at tree-climbing. But, the hand also had a long thumb and short fingers, which is a sign of precision gripping—a grip that just involves the thumb and fingers, but not the palm. It's even possible that Au. sediba had already started dabbling with tool-making, the researchers say.

"The hand is one of the very special features of the human lineage, as it's very different from the hand of the apes," said Kivell. "Apes have long fingers for grasping branches or for use in locomotion, and thus relatively short thumbs that make it very difficult for them to grasp like a human."

"Au. sediba has, in contrast, a more human-like hand that has shortened fingers and a very long thumb," continued Kivell. "Although at the same time, it appears to have possessed very powerful muscles for grasping. Our team interpreted this as a hand, capable of tool manufacture and use, but still in use for climbing and certainly capable of human-like precision grip."

The findings don't mean that Au. sediba was the only hominin around two million years ago who was capable of making stone tools, though. (Homo habilis, or the "handy man," was on the scene, but this hominin had a very different hand structure.) These latest findings do indicate, however, that different hominins with various hand morphologies may have been around at the same time, fashioning simple tools.

Finally, an analysis of the feet and ankles of MH-1 and MH-2 demonstrate that Au. sediba probably climbed trees sometimes and practiced a unique form of bipedal walking. Bernhard Zipfel from the University of the Witwatersrand and colleagues say that the MH-2 ankle is one of the most complete hominin ankles ever found—and at the same time, no ankle has ever been described with so many primitive and advanced features.

"…If the bones had not been found stuck together, the team may have described them as belonging to different species," said Zipfel.

The ankle joint is largely like a human's, with some evidence for a human-like arch and a well-defined Achilles tendon, according to the researchers. However, its heel and shin bone appear to be mostly ape-like.

This mix of modern and primitive characteristics evokes the image of a hominin who helped to usher in the various Homo species two million years ago. But, only time (and more research) will tell exactly how MH-1 and MH-2 were related to our own human lineage.

"The fossil record for early Homo is a mess," said Churchill. "Many fossils are either questionably attributed to various species or their dating is very poor… Au. sediba has a number of derived characteristics, which it shares with the genus Homo. If you were to make a list of these shared traits—including those seen in habilis, rudolfensis and sediba—the list for sediba would be much longer than the other two, which suggests it's a good ancestor of the first species that everyone recognizes in the Homo genus: H. erectus."

There are a lot of links to this story. Here are a few:
  • Nature
  • The Guardian
  • NPR
  • Science News
  • National Geographic News
  • Live Science


    EurekAlert. 2011. "Australopithecus sediba paved the way for Homo species, new studies suggest". EurekAlert. Posted: September 8, 2011. Available online:
  • Wednesday, September 21, 2011

    Linguist revives lost Aboriginal language

    GAMO, Bama, Jambon - forgotten words from a lost language. But Japanese linguist Professor Tasaku Tsunoda hopes to change that.

    Professor Tsunoda travelled to the Aboriginal community of Palm Island this week to re-establish a severed link with the past.

    As surprising as it may seem, he's the last living speaker of the Worrongo language, a native tongue of Aboriginal clans living around Townsville and Palm Island.

    While visiting Palm Island in the 1970s as a linguistics student, Professor Tsunoda met a local elder named Alf Palmer who, fearing that his language would die with him, passed on his knowledge of Worrongo to the young Japanese man.

    From his recordings of Mr Palmer, Professor Tsunoda was able to create a 1500-word dictionary and 900-word grammar guide for Worrongo.

    He returned to the island as part of a program established by the Australian Literacy & Numeracy Foundation (ALNF) to teach traditional languages to Aboriginal children.

    With Professor Tsunoda's help the foundation is producing reading and teaching material to help local children learn the language.

    He has even provided translations of classic children's books such as The Very Hungry Caterpillar, and recorded a Worrongo version of Kookaburra Sits in the Old Gum Tree, to help Palm Island kids learn the language.

    ALNF founder Mary-Ruth Mendel said Professor Tsunoda received a "magical" reception.

    "The children were just drawn to him, boys walked up and hugged him and parents brought their kids up to receive a Worrongo name," she said.

    "It is quite remarkable, he is the children's professor."

    During his brief visits, Professor Tsunoda was able to teach children a few simple words including: Gamo (water), Bama (man) and Jambon (witchetty grub), and hopes his learning materials will lead to the revival of the Worrongo language.

    "Language is a very important part of a people's identity and you could see how important it was when we were on Palm Island," he said.

    While on the island he visited Mr Palmer's grave to tell his friend, in Worrongo, that he was bringing his language back.

    "I said I am your friend, I have brought these people here to talk to you, we want to learn your language, we are making books for your language," he said.

    He considered it "very special" to be able to visit Palm Island again and hopefully revive his friend's language.

    Ms Mendel said helping indigenous children to become fluent in traditional languages not only boosted their self esteem and established a link to their heritage, but also helped them to learn English.

    Children in Aboriginal communities typically fall well below the national average for literacy levels but Ms Mendel said the structural similarities between aboriginal languages and Latin made it easier for those fluent in a native tongue to learn English.

    However, she said the foundation needed greater funding to establish similar projects in other parts of Australia.

    Schwarten, Evan. 2011. "Linguist revives lost Aboriginal language ". The Australian. Posted: September 12, 2011. Available online:

    Tuesday, September 20, 2011

    The secret life of pronouns

    The smallest words in our vocabulary often reveal the most about us, including our levels of honesty and thinking style

    STOP for a moment and think about your most recent conversation, email, tweet or text message. Perhaps you think you said something about dinner plans, domestic chores or work. And you probably did. But at the same time, you said much more. The precise words you used revealed more about you than you can imagine.

    Hidden inside language are small, stealthy words that can reveal a great deal about your personality, thinking style, emotional state and connections with others. These words account for less than 0.1 per cent of your vocabulary but make up more than half of the words commonly used. Your brain is not wired to notice them but if you pay close attention, you will start to see their subtle power.

    I'm a social psychologist whose interest in these words came about almost accidentally. In the early 1980s, I stumbled on a finding that fascinated me. People who reported having a traumatic experience and who kept the experience a secret had far more health problems than people who talked openly. Why would keeping a secret be so unhealthy? If you asked people to write about their secrets, would their health improve? The answer, I soon discovered, was yes.

    As part of this work, we developed a computer program to analyse the language people used when they wrote about traumas. We made numerous discoveries using this tool, such as the value of using words associated with positive emotions.

    However, our most striking discovery was not about the content of people's writing but the style. In particular, we found that the use of pronouns – I, me, we, she, they – mattered enormously. The more people changed from using first-person singular pronouns (I, me, my) to using other pronouns (we, you, she, they) from one piece of writing to the next, the better their health became. Their word use reflected their psychological state.

    This was the prelude to a more substantial discovery that has become my life's work. I found myself reading endless reams of text to analyse language style. For example, I wondered if there were any gender distinctions and found that yes, there were significant differences.

    As I played with more and more words, certain patterns kept recurring. Not only was gender a factor, there were large differences in language style as a function of people's age, social class, emotional state, level of honesty, personality, degree of formality, leadership ability, quality of relationships and so on. Word use was associated with almost every dimension of social psychology I studied.

    I'm now convinced that by understanding language style, we gain a far clearer sense of the social and psychological processes affecting our behaviours.

    What do I mean by style? In any given sentence, there are two basic types of word. The first is content words, which provide meaning. These include nouns (table, uncle), verbs (to love, to walk), adjectives (blue, mouthwatering) and adverbs (sadly, hungrily).

    The other type are "function" words. These serve quieter, supporting roles – connecting, shaping and organising the content words. They are what determines style.

    Function words include pronouns (I, she, it), articles (a, an, the), prepositions (up, with), auxiliary verbs (is, don't), negations (no, never), conjunctions (but, and), quantifiers (few, most) and common adverbs (very, really). By themselves, they don't have much meaning. Whereas a content word such as "table" can trigger an image in everyone's mind, try to imagine "that" or "really" or "the".

    Why make such a big deal about these words? Because they are the keys to the soul. OK, maybe that's an overstatement, but bear with me.

    Function words are psychologically very revealing. They are used at high rates, while also being short and hard to detect. They are processed in the brain differently than content words. And, critically, they require social skills to use properly. It's about time that these forgettable little words got their due.

    In November 1863, four months after the devastating Battle of Gettysburg, Abraham Lincoln delivered one of the most significant speeches in American history:

    Four score and seven years ago our fathers brought forth, upon this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.

    Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived, and so dedicated, can long endure. We are met here on a great battlefield of that war. We have come to dedicate a portion of it as a final resting place for those who here gave their lives that that nation might live. It is altogether fitting and proper that we should do this.

    But in a larger sense we can not dedicate – we can not consecrate – we can not hallow this ground. The brave men, living and dead, who struggled, here, have consecrated it far above our poor power to add or detract. The world will little note, nor long remember, what we say here, but can never forget what they did here.

    It is for us, the living, rather to be dedicated here to the unfinished work which they have, thus far, so nobly carried on. It is rather for us to be here dedicated to the great task remaining before us – that from these honored dead we take increased devotion to that cause for which they here gave the last full measure of devotion – that we here highly resolve that these dead shall not have died in vain; that this nation shall have a new birth of freedom; and that this government of the people, by the people, for the people, shall not perish from the earth.

    Close your eyes and reflect on the content of the speech. Which words occurred most frequently? Most people say "nation", "war", "men" and possibly "dead". Not so. The most commonly used word is "that", followed by "the". Only one content word is in the top 15 – "nation". It is remarkable that such a great speech can be largely composed of small, insignificant words.

    But this is typical. A very small number of function words account for most of the words we hear, read and say. Over the past 20 years, my colleagues and I have analysed billions of written and spoken words and compiled a list of the most common. Every one of the top 20 is a function word; together they account for almost 30 per cent of all words that we use, read and hear. English has about 450 common function words in total, which account for 55 per cent of all the words we use.

    To put this into perspective, the average English speaker has a vocabulary of perhaps 100,000 words. More than 99.9 per cent of this is made up of content words but these account for less than half of the words we use. This split is comparable in other languages.

    Function words are both short and hard to perceive. One reason we have trouble spotting their high rate of usage is that our brains naturally slide over them. We automatically focus on content words as they provide the basic who, what and where of a conversation.

    This distinction can also be seen in people with brain damage. Occasionally, a person will have a brain injury that affects their ability to use content words but not function words. Injuries in other areas can produce the opposite results.

    The two brain regions of interest are Broca's and Wernicke's areas. If a person with damage to their Broca's area were asked to describe a picture of, say, a girl and an old woman, he or she might say, "girl… ummm… woman… ahh… picture, uhhh… old." Someone with a damaged Wernicke's area might say, "Well, right here is one of them and I think she's next to that one. So if I see over there you'll see her too." To say that Broca's area controls style words and Wernicke's controls content words is a gross oversimplification. Nevertheless, it points to the fact that the distinction between content and style words is occurring at a fairly basic level in the brain. Interestingly, Broca's area is in the frontal lobe of the brain, which controls a number of social skills.

    Brain research, then, supports the conclusion that function words are related to our social worlds. To see just how social, imagine finding this note on the street:


    The note is grammatically correct and is understandable in a certain sense, but we have no real idea what it means. Every word is a function word. Whoever wrote the note had a shared understanding with its intended recipient of who "he" is, where "here" is, and so on.

    Now you find out the note was written by Bob to Julia, who had the following phone conversation a few minutes earlier:

    Bob: Hi, you caught me at a crazy time. I've got to go out but I'll leave a note on the door.

    Julia: Great. I need the accountant to sign my expense form. Do you know where he is?

    Bob: I'll see if he's in.

    Julia: Did I tell you that I'm thinking of taking up smoking again? I know it annoys you.

    Bob: Are you nuts? Let's talk about this.

    All of a sudden, the note makes sense.

    Function words require social skills to use properly. The speaker assumes the listener knows who everyone is and the listener must know the speaker to follow the conversation. The ability to understand a simple conversation packed full of function words demands social knowledge. All function words work in this way. The ability to use them is a marker of basic social skills – and analysing how people use function words reveals a great deal about their social worlds.

    That is not to say a single sentence is particularly revealing. If you mention "a chair" versus "that chair", it says very little about you. But what if we monitored your words over the course of a week? What if we found that you use "a" and "the" at high rates, or hardly at all?

    In fact, there are people who use articles at very high rates and others who rarely use them. Men tend to use them at higher rates than women. Gender aside, high article users tend to be more organised, emotionally stable, conscientious, politically conservative and older.

    Now things start to get interesting. It seems the use of articles can tell us about the ways people think, feel and connect with others. The same is true for pronouns, prepositions, and virtually all function words.

    One area this is useful is in personality research. As you might guess, different patterns of function words reveal important parts of people's personalities.

    In one experiment, we analysed hundreds of essays written by my students and we identified three very different writing styles: formal, analytic and narrative.

    Formal writing often appears stiff, sometimes humourless, with a touch of arrogance. It includes high rates of articles and prepositions but very few I-words, and infrequent discrepancy words, such as "would", and adverbs. Formality is related to a number of important personality traits. Those who score highest in formal thinking tend to be more concerned with status and power and are less self-reflective. They drink and smoke less and are more mentally healthy, but also tend to be less honest. As people age, their writing styles tend to become more formal.

    Analytical writing, meanwhile, is all about making distinctions. These people attain higher grades, tend to be more honest, and are more open to new experiences. They also read more and have more complex views of themselves.

    Narrative writers are natural storytellers. The function words that generally reveal storytelling involve people, past-tense verbs and inclusive words such as "with" and "together". People who score high for narrative writing tend to have better social skills, more friends and rate themselves as more outgoing.

    By watching how people use function words, we gain insight into how they think, how they organise their worlds and how they relate to other people.

    This work on personality only scratches the surface. We have also found that function words can detect emotional states, spot when people are lying, predict where they rank in social hierarchies and the quality of their relationships. They reveal much about the dynamics within groups. They can be used to identify the authors of disputed texts, and much more.

    The smallest, stealthiest words in our vocabulary often reveal the most about us.

    Pennebaker, James W. 2011. "The secret life of pronouns". New Scientist. Posted: September 7, 2011. Available online:

    Monday, September 19, 2011

    Language speed vs. efficiency: Is faster better?

    A recent study of the speech information rate of seven languages concludes that there is considerable variation in the speed at which languages are spoken, but much less variation in how efficiently languages communicate the same information. The study, "A cross-linguistic perspective on speech information rate," to be published in the September 2011 issue of the scholarly journal Language, is co-authored by François Pellegrino, Christophe Coupé, and Egidio Marsico. A preprint version is available on line at

    Their research sheds new light on the ways in which languages ensure the efficient communication of information. The study is based on 20 short texts (each consisting of five sentences) translated into seven languages (Mandarin Chinese, English, French, German, Japanese, Italian, and Spanish) and pronounced by about 60 native speakers. Dr. Pellegrino outlined the major findings of the team's research: "Languages do need more or less time to tell the same story – for instance in our study, the texts spoken in English are much shorter than their Japanese counterparts. Despite those variations, there is a tendency to regulate the information rate, as shown by a strong negative correlation between the syllabic rate and the information density." In other words, languages that are spoken faster (i.e., that have a higher syllabic rate) tend to pack less information into each individual syllable (i.e. have a lower information density).

    As Dr. Pellegrino notes, "this result illustrates that several encoding strategies are possible. For instance, Spanish is characterized by a fast rate of low-information syllables, while Mandarin exhibits a slower syllabic rate with more informative syllables. In the end, their information rates are very similar (differing only by four percent)." Furthermore, Dr. Pellegrino concluded, "we discovered a strong relationship between the information density of the syllables and the complexity of their linguistic structure." Pellegrino and colleagues' result confirms the existence of distinct linguistic ways of packing information into syllables which eventually interact with the actual speech rate to result in a tendency toward a uniform information rate.

    The origin of the speech regulation remains unclear and the team explores several hypotheses in the article involving cognitive or social factors for potential follow-on research. Whether this variation involves cognitive or social factors, it also affirms our appreciation for the richness of languages and their power of expression across different cultures and peoples.

    EurekAlert. 2011. "Language speed vs. efficiency: Is faster better?". EurekAlert. Posted: September 1, 2011. Available online:

    Sunday, September 18, 2011

    Myth-Making: Say It Often, People Will Believe

    The United States is reeling from a hurricane, drought, heat waves, and even an earthquake in Virginia. And we're already well into a nasty national election campaign.

    Now is the time to get those rumors flying, because science is proving what most of us already know: If you say something often enough, people will believe it, even if it seems too far out at first to be taken seriously.

    Why are people so eager to embrace myths, even if there is not a shred of evidence to support them? Why are so many so eager to believe the unbelievable?

    It's no surprise that myths are common in politics, but they invade every field of thought, including science, even when they have been shown to be false. They spread at lightning speed in these days of social media, 24-hour television news, and instant global communications. They aren't harmless.

    And it's so easy to do.

    Here's how it's done, according to a new mathematical model for rumor-mongering offered by a physicist turned linguist, Lukasz Debowski, although there's no reason to believe he intentionally planned to throw fuel on the rumor mill. His prescription, developed through incredibly complex mathematics, is this:

    Say it often. Keep it short.

    That formula is backed by research among psychologists and sociologists who have studied the spread of myths in recent years, including psychologist Norbert Schwarz of the University of Michigan, who found that it doesn't take many believers to spread a rumor. A single voice, heard often enough, can sound like a chorus. And it doesn't seem to make much difference whether or not that single voice is credible.

    In his research, Schwarz used a flier put out by the Centers for Disease Control that was intended to knock down rumors that flu shots were harmful. Within 30 minutes after they read the flier, a fourth of the older participants in the study believed the false rumors were true, and that rose to 40 percent in just three days. Younger people fared no better. So a flier that was designed to discredit rumors actually reinforced them.

    If you think that's exceptional, ask a few friends if they think flu shots can cause autism.

    Gregory Poland of the Mayo Clinic in Rochester, Minn., has reason to view that with alarm. His clinic issued a news release Tuesday warning that measles are making a comeback in this country and Europe because many parents believe the inoculation has been linked to autism.

    That belief grew out of a paper published in 1998 by the British medical journal, The Lancet. It has since been retracted because it was found to be based on fraudulent research. So it clearly is not true, even though some celebrities have urged parents to refuse to immunize their children against the potentially deadly virus. Thus, the myth survives clear scientific evidence.

    Some scientists, including pediatricians Aaron Carroll and Rachel Vreeman of the Indiana University School of Medicine, have spent years debunking myths. It is not true that cold weather can give you a cold (colds are caused by a virus, not temperature). Frogs do not give you warts. Chewing gum does not stay in your stomach for seven years.

    But the question persists: Why do so many continue to believe claims that have no basis in fact?

    Many psychologists have pointed to a problem all of us have encountered. We believe some things just because we want to think they are true. Psychologist Nicholas DiFonzo adds another element. Humans have a desperate need to make sense out of a world that often seems senseless. We believe, because the alternative seems unacceptable.

    And sometimes, especially in politics, it's just convenient to say you believe, even if you don't. How else can you explain so many politicians running for high office, including the presidency of the United States, who deny global climate change in the face of overwhelming evidence? Perhaps their constituents, who have heard over and over that we are partly to blame, can't buy it.

    But of all the fields of science, the one that is most plagued by myths is evolution. For openers, evolution is not a theory, it is a fact. The evidence, which critics call lacking, is so powerful that virtually every major research university in the world has a department of evolutionary biology.

    The debate among scientists is not over whether Charles Darwin's revolutionary ideas were fundamentally correct. They do debate details, but not the substance.

    There are scores of excellent books available to anyone with a curious mind that will lay out the fundamentals of evolutionary science. One of the best is very recent, "Here Be Dragons," by Dennis McCarthy, a researcher at the Museum of Natural History at Buffalo. McCarthy's brilliant work traces the evolution of hundreds of plants and animals around the world, leading to the conclusion that the vast diversity of species could only have occurred through natural selection, or "survival of the fittest," as so apply described by Darwin so many years ago.

    Evolution will remain on the front burner among myth-makers in the coming months because some candidates will chose to deny it. Chances are they will say it often, and keep it brief, and their supporters will offer them praise.

    But it's ignorance, or cowardice, that will make them do it. It's not all that hard to understand one of the most important discoveries in human history.

    So beware the sound bite. Especially if you hear it often.

    Dye, Lee. 2011. "Myth-Making: Say It Often, People Will Believe". ABC News. Posted: September 1, 2011. Available online:

    Saturday, September 17, 2011

    A human face to the convict past of Australia

    University of Manchester archaeologist Dr Eleanor Casella says the find of textile manufacturing paraphernalia in a Tasmanian prison nursery proves women prisoners were allowed informal contact with their babies – a contravention of official British policy for the management of imperial convicts.

    Dr Casella had spotted three intact lead bale seals while excavating the nursery of the Ross Female Factory, a heritage-listed prison which confined British criminal women and their children exiled to Van Diemen’s Land – now Tasmania. They were put to use making convict uniforms out of cotton and woollens imported from the textile factories of north-west England. The lead seals – which prevent theft from the bolts of cloth during export down to the penal colonies –were found alongside fragments of buttons, sewing pins and thimbles.

    Dr Casella who has been excavating at the Ross Factory site for over 15 years said: “Strict official regulations kept criminal mothers separated from their children. It was a dark period for many thousands of people, but the bale seals and other textile-related fragments we found suggest the Ross Factory Superintendent ignored formal orders and allowed women to complete their required work assignments in the company of their children.”

    She pointed out that this was a direct and never before documented subversion of the British penal regulations that governed this penal colony. So though it was a dark and brutal period, these artefacts attribute a human side to these colonialists.

    The Superintendent at the time was a Dr Edward Swarbeck Hall, a minor figure in Australian colonial history. As Swarbeck was known within Tasmania as a “thorough disciplinarian”, historians will now need to modify their appraisal of him.

    Officially, the women were not allowed to see their babies within the Ross Factory nursery other than for breast feeding. At the age of three, the ‘convict babies’ were transferred to the Queen’s Orphan School in Hobart Town, approximately 70 miles away from Ross. However, evidence is also emerging that the prisoners appealed to the Governor who quietly allowed them to find work close to their children once they had left prison.

    Dr Casella said: “We have no way of knowing if these acts of kindness happened across Britain’s penal colonies – but I suspect they did.“ She added “There were colonial prisons across the British empire: in Australia alone, 12,000 women were exiled to Tasmania between 1803 and 1854, and an additional 12,000 had previously been sent to New South Wales from 1788 to 1840. It’s one thing to concoct draconian rules 8,000 miles away in London – but to make a society function properly, the local hierarchy had much to gain from letting people get on with their lives.”

    One of the lead seals was impressed with the stamp of the Royal Army Ordnance Corp — the branch of Her Majesty’s Army charged with provisioning the Imperial prisons throughout the Australian penal colonies. They are about an inch in diameter and were used as a security seal which was pressed into the cloth to show if it had been tampered with.

    The seals, currently in Manchester, have been conserved and cleaned at the Museum of London, and will be returned to the Queen Victoria Museum in Tasmania to join permanent exhibitions. The excavation and conservation of the bale seals was funded by a British Academy grant.

    Past Horizons. 2011. "A human face to the convict past of Australia". Past Horizons. Posted: August 31, 2011. Available online:

    Friday, September 16, 2011

    Black Death bug identified from medieval bones

    The Black Death infamously wiped out about a third of Europe's population in the 14th century, but until now there was no firm evidence that bubonic plague was the cause.

    Some researchers have suggested that the epidemic was caused by a virus such as Ebola, but an analysis of DNA from a London plague pit seems to settle the argument in favour of the "plague" bacterium Yersinia pestis.

    Hendrik Poinar at McMaster University in Hamilton, Ontario, Canada, and colleagues developed a technique to look for Yersinia DNA in the bones of Black Death victims. The task was made tricky because of the possibility of contamination, Poinar says. "When we extract DNA from the skeletons, we also get DNA from their environment."

    To pick out the signature of Y. pestis, Poinar's team took DNA from a modern strain and made a molecular "probe" that would bind to DNA from this type of bacterium. The team attached a magnetic chip to the probe and tested it on around 100 samples of teeth and bone excavated from a London plague pit.

    Then they used a magnet to fish out the chips, which carried bacterial DNA belonging to a strain of Y. pestis unlike any known today. The DNA was not present in teeth from skeletons buried elsewhere in London before the Black Death.

    First confirmation

    The findings are the first confirmation that these Black Death victims were infected with Y. pestis, Poinar says. The evidence was strong enough to convince two team members who had previously argued that the bug was not the cause.

    Tom Gilbert at the University of Copenhagen, Denmark, who was not involved with the work, is convinced too. "I've been sceptical of previous research on this topic," he says. "What makes this work stand out is its very clever approach."

    Both Gilbert and Poinar reckon the technique could uncover the full genetic sequence of the bacterial strain behind the Black Death, which could help explain both why it was so virulent and how it evolved – as well as whether similarly devastating strains might appear in future.

    "This technology will open up a brave new world of ancient pathogen identification," Poinar says.

    Hamzelou, Jessica. 2011. "Black Death bug identified from medieval bones ". New Scientist. Posted: August 30, 2011. Available online:

    Thursday, September 15, 2011

    Localizing language in the brain

    New study pinpoints areas of the brain used exclusively for language, providing a partial answer to a longstanding debate in cognitive science

    New research from MIT suggests that there are parts of our brain dedicated to language and only language, a finding that marks a major advance in the search for brain regions specialized for sophisticated mental functions.

    Functional specificity, as it's known to cognitive scientists, refers to the idea that discrete parts of the brain handle distinct tasks. Scientists have long known that functional specificity exists in certain domains: In the motor system, for example, there is one patch of neurons that controls the fingers of your left hand, and another that controls your tongue. But what about more complex functions such as recognizing faces, using language or doing math? Are there special brain regions for those activities, or do they use general-purpose areas that serve whatever task is at hand?

    Language, a cognitive skill that is both unique to humans and universal to all human cultures, "seems like one of the first places one would look" for this kind of specificity, says Evelina Fedorenko, a research scientist in MIT's Department of Brain and Cognitive Sciences and first author of the new study. But data from neuroimaging — especially functional magnetic resonance imaging (fMRI), which measures brain activity associated with cognitive tasks — has been frustratingly inconclusive. Though studies have largely converged on several areas important for language, it's been hard to say whether those areas are exclusive to language. Many experiments have found that non-language tasks seemingly activate the same areas: Arithmetic, working memory and music are some of the most common culprits.

    But according to Fedorenko and her co-authors — Nancy Kanwisher, the Walter A. Rosenblith Professor of Cognitive Neuroscience, and undergraduate student Michael Behr — this apparent overlap may simply be due to flaws in methodology, i.e., how fMRI data is traditionally gathered and analyzed. In their new study, published in this week's Proceedings of the National Academy of Sciences, they used an innovative technique they've been developing over the past few years; the new method yielded evidence that there are, in fact, bits of the brain that do language and nothing else.

    Forget the forest, it's all in the trees

    fMRI studies of language are typically done by group analysis, meaning that researchers test 10, 20 or even 50 subjects, then average data together onto a common brain space to search for regions that are active across brains.

    But Fedorenko says this is not an ideal way to do things, mainly because the fine-grained anatomical differences between brains can cause data "smearing," making it look as if one region is active in two different tasks when in reality, the tasks activate two neighboring — but not overlapping — regions in each individual subject.

    By way of analogy, she says, imagine taking pictures of 10 people's faces and overlaying them, one on top of another, to achieve some sort of average face. While the resulting image would certainly look like a face, when you compared it back to the original pictures, it would not line up perfectly with any of them. That's because there is natural variation in our features — the size of our foreheads, the width of our noses, the distance between our eyes.

    It's the same way for brains. "Brains are different in their folding patterns, and where exactly the different functional areas fall relative to these patterns," Fedorenko says. "The general layout is similar, but there isn't fine-grained matching." So, she says, analyzing data by "aligning brains in some common space … is just never going to be quite right."

    Ideally, then, data would be analyzed for each subject individually; that is, patterns of activity in one brain would only ever be compared to patterns of activity from that same brain. To do this, the researchers spend the first 10 to 15 minutes of each fMRI scan having their subject do a fairly sophisticated language task while tracking brain activity. This way, they establish where the language areas lie in that individual subject, so that later, when the subject performs other cognitive tasks, they can compare those activation patterns to the ones elicited by language.

    A linguistic game of 'Where's Waldo?'

    This methodology is exactly what allows Fedorenko, Behr and Kanwisher to see if there are areas truly specific to language. After having their subjects perform the initial language task, which they call a "functional localizer," they had each one do a subset of seven other experiments: one on exact arithmetic, two on working memory, three on cognitive control and one on music, since these are the functions "most commonly argued to share neural machinery with language," Fedorenko says.

    Out of the nine regions they analyzed — four in the left frontal lobe, including the region known as Broca's area, and five further back in the left hemisphere — eight uniquely supported language, showing no significant activation for any of the seven other tasks. These findings indicate a "striking degree of functional specificity for language," as the researchers report in their paper.

    Future studies will test the newly identified language areas with even more non-language tasks to see if their functional specificity holds up; the researchers also plan to delve deeper into these areas to discover which particular linguistic jobs each is responsible for.

    Fedorenko says the results don't imply that every cognitive function has its own dedicated piece of cortex; after all, we're able to learn new skills, so there must be some parts of the brain that are both high-level and functionally flexible. Still, she says, the results give hope to researchers looking to draw some distinctions within in the human cortex: "Brain regions that do related things may be nearby … [but] it's not just all one big mushy multifunctional thing in there."

    EurekAlert. 2011. "Localizing language in the brain ". EurekAlert. Posted: August 30, 2011. Available online:

    Wednesday, September 14, 2011

    Bilingual babies' vocabulary linked to early brain differentiation

    Babies and children are whizzes at learning a second language, but that ability begins to fade as early as their first birthdays.

    Researchers at the University of Washington's Institute for Learning & Brain Sciences are investigating the brain mechanisms that contribute to infants' prowess at learning languages, with the hope that the findings could boost bilingualism in adults, too.

    In a new study, the researchers report that the brains of babies raised in bilingual households show a longer period of being flexible to different languages, especially if they hear a lot of language at home. The researchers also show that the relative amount of each language – English and Spanish – babies were exposed to affected their vocabulary as toddlers.

    The study, published online Aug. 17 in Journal of Phonetics, is the first to measure brain activity throughout infancy and relate it to language exposure and speaking ability.

    "The bilingual brain is fascinating because it reflects humans' abilities for flexible thinking – bilingual babies learn that objects and events in the world have two names, and flexibly switch between these labels, giving the brain lots of good exercise," said Patricia Kuhl, co-author of the study and co-director of the UW's Institute for Learning & Brain Sciences.

    Kuhl's previous studies show that between 8 and 10 months of age, monolingual babies become increasingly able to distinguish speech sounds of their native language, while at the same time their ability to distinguish sounds from a foreign language declines. For instance, between 8 and 10 months of age babies exposed to English become better at detecting the difference between "r" and "l" sounds, which are prevalent in the English language. This is the same age when Japanese babies, who are not exposed to as many "r" and "l" sounds, decline in their ability to detect them.

    "The infant brain tunes itself to the sounds of the language during this sensitive period in development, and we're trying to figure out exactly how that happens," said Kuhl, who's also a UW professor of speech and hearing sciences. "But almost nothing is known about how bilingual babies do this for two languages. Knowing how experience sculpts the brain will tell us something that goes way beyond language development."

    In the current study, babies from monolingual (English or Spanish) and bilingual (English and Spanish) households wore caps fitted with electrodes to measure brain activity with an electroencephalogram, or EEG, a device that records the flow of energy in the brain. Babies heard background speech sounds in one language, and then a contrasting sound in the other language occurred occasionally.

    For example, a sound that is used in both Spanish and English served as the background sound and then a Spanish "da" and an English "ta" each randomly occurred 10 percent of the time as contrasting sounds. If the brain can detect the contrasting sound, there is a signature pattern called the mismatch response that can be detected with the EEG.

    Monolingual babies at 6-9 months of age showed the mismatch response for both the Spanish and English contrasting sounds, indicating that they noticed the change in both languages. But at 10-12 months of age, monolingual babies only responded to the English contrasting sound.

    Bilingual babies showed a different pattern. At 6-9 months, bilinguals did not show the mismatch response, but at 10-12 months they showed the mismatch for both sounds.

    This suggests that the bilingual brain remains flexible to languages for a longer period of time, possibly because bilingual infants are exposed to a greater variety of speech sounds at home.

    This difference in development suggests that the bilingual babies "may have a different timetable for neurally committing to a language" compared with monolingual babies, said Adrian Garcia-Sierra, lead author and a postdoctoral researcher at UW's Institute for Learning & Brain Sciences.

    "When the brain is exposed to two languages rather than only one, the most adaptive response is to stay open longer before showing the perceptual narrowing that monolingual infants typically show at the end of the first year of life," Garcia-Sierra said.

    To see if those brain responses at 10-12 months related to later speaking skills, the researchers followed up with the parents when the babies were about 15 months old to see how many Spanish and English words the children knew. They found that early brain responses to language could predict infants' word learning ability. That is, the size of the bilingual children's vocabulary was associated with the strength of their brain responses in discriminating languages at 10-12 months of age.

    Early exposure to language also made a difference: Bilingual babies exposed to more English at home, including from their parents, other relatives and family friends, subsequently produced more words in English. The pattern held true for Spanish.

    The researchers say the best way for children to learn a second language is through social interactions and daily exposure to the language.

    "Learning a second language is like learning a sport," said Garcia-Sierra, who is raising his two young children as bilingual. "The more you play the better you get."

    EurekAlert. 2011. "Bilingual babies' vocabulary linked to early brain differentiation ". EurekAlert. Posted: August 29, 2011. Available online:

    Tuesday, September 13, 2011

    Aztec Maps Put Cortés to Shame

    As far as tax collectors in colonial Mexico went, Gonzalo de Salazar, often dubbed "El Gordo," was a pinchpenny. The conquistador-turned-regional-chief demanded steep tributes from his charges living in an area called Tepetlaoxtoc just north of what is now Mexico City. To expose El Gordo's greed, census takers from the Acolhua-Aztecs, a subset of the larger Aztec group, set out to count their own numbers in the mid-1500s and tally the extent of their farmland and hence their tax burden. They did a remarkably good job, a new study suggests. The early surveyors calculated the sizes of their farms with a degree of accuracy likely beyond the means of El Gordo or his cronies.

    The Tepetlaoxtoc census, also known as the Codex Vergara, was much more than a simple survey. This paint-on-paper record incorporated icons for every adult and child in the region, as well as detailed maps for at least 386 farms. The surveyors measured the borders around each of these fields and then calculated their areas in square tlalcuahuitls, units equal to roughly 2.5 meters.

    Using these records, Clara Garza-Hume, a mathematician at the National Autonomous University of Mexico in Mexico City, and colleagues went back to the codex to check the Aztecs' math. That was easy for the rectangular-shaped farms but much harder for the more than 200 recorded plots that, although still four-sided, lacked that uniform shape. The Aztecs hadn't yet stumbled upon trigonometry, so their maps failed to record at what angles the farms' borders joined up. Since the exact angles weren't clear from the maps, such odd four-sided shapes could have taken on a number of different forms, Garza-Hume says. "The side lengths remain constant, but you can still wiggle the figure and obtain many different areas."

    What the team could do, however, was calculate the wiggle range of possible shapes for each of the fields. And the surveyors "did quite well" in matching those shapes, she says. The Aztecs calculated the sizes of their farms within a 10% error range about 85% of the time, Garza-Hume and her colleagues report online today in the Proceedings of the National Academy of Sciences. The few high guesses likely stemmed from reliance on the "surveyor's rule" to compute areas, she adds. This old trick, in which surveyors average out the lengths of a quadrilateral's opposing sides and then multiply them together, is notorious for giving high numbers.

    But the Aztecs could just have easily have fudged their measurements, trying to trick their governor out of a few spools of cloth. Luckily, a field near the modern town of Texcoco still vouches for their honesty; this sloping lot contains the remnants of 38 old farms censused in the codex. The boundaries between the individual plots here had long ago eroded away, but Garza-Hume and her colleagues could still make out the larger borders of the region. Using GPS markers, they reckoned that the 38 farms had once taken up about 135,577 square meters, not too far off from the Aztecs' estimate of 124,072 square meters. El Gordo can keep his place in infamy.

    Although El Gordo fought against lower taxes, the Codex Vergara did put the Spanish in their place, at least mathematically. Early colonialists were largely clueless when it came to land surveys, rarely knowing for sure where their expansive cattle ranches started or stopped, says Andrew Sluyter, a geographer at Louisiana State University in Baton Rouge. "Really, you don't get to that kind of map in Mexico ... until the Enlightenment, the 1700s."

    Studies like these are important because they show the Mesoamericans' prowess in fields outside of astronomy, says Michael Smith, an archaeologist at Arizona State University, Tempe. Hernán Cortés and his countryman burned library after library in the old Aztec kingdom, leaving few records of day-to-day achievements behind. Still, indigenous Mexicans didn't always use their record-keeping acumen for good, Smith adds. The Aztecs, conquerors themselves, would have needed meticulous notes to squeeze every penny out of their squashed foes.

    Strain, Daniel. 2011. "Aztec Maps Put Cortés to Shame". . Posted: August 29, 2011. Available online:

    Monday, September 12, 2011

    Where the tongue hits its limits

    LMU phonetician wins prestigious EU grant

    Marianne Pouplier, a phonetician of the Institute of Phonetics and Speech Processing at LMU Munich has won one of the prestigious Starting Grants awarded by the European Research Council (ERC). She received the accolade, worth approximately 1.5 million euros, for a proposed project on "Stability and change in sound patterns of the world's languages". With its Starting Grants the ERC aims to facilitate cutting-edge research by supporting especially innovative projects proposed by highly creative young academics.

    The world's languages are extraordinarily diverse, and yet there are certain sound patterns that turn up in most, or even all of them over and over again. For instance, all languages distinguish between consonants and vowels, and most words are made up of more or less regular sequences of consonants and vowels. Nevertheless, there are sound structures that turn up very rarely. In Georgian, for instance, there are words that consist entirely of consonants. One example is the word "prtskvn", which means "to peel". For linguists, the question of the limits of linguistic diversity is of great interest, because universal patterns can tell us something about the evolutionary development of language as such, and throw light on the significance of physiological and cognitive factors in its origin and diversification. Exactly why particular sound patterns are rarely encountered is an issue that is hotly debated among linguists, psychologists and cognitive scientists. In her project, Marianne Pouplier wants to clarify whether or not rare sound patterns are really "tongue-twisters" – sequences that are much more difficult to articulate, discriminate perceptually and harder to learn than others. If that is so, it would explain why they occur infrequently. To tackle the problem, she has chosen an empirical approach. She will use ultrasound imaging to observe the movements of the tongue, in order to analyze the complexity of the motor patterns required to produce rare sound sequences. Furthermore, she will use perceptual tests to study whether the brain actually takes more time to process rare sound patterns. In its use of a combination of empirical methods, the project suggests new ways of probing the nature of speech universals and their significance for the cognitive processing of sound sequences in natural languages. (göd)

    Marianne Pouplier studied German and English at the University of Freiburg, and graduated 1998. From 1999 until 2003 she was a member of the scientific staff of Haskins Laboratories, and obtained her PhD from Yale University in 2003 (USA) . She then served as a Postdoctoral Research Fellow at the Universities of Maryland (USA) and Edinburgh (UK). Since 2007 Pouplier has led an Emmy Noether Junior Research Group at LMU's Institute of Phonetics and Speech Processing. The group focuses on aspects of "Timing and Cohesion of Gestures in Speech Production".

    EurekAlert. 2011. "Where the tongue hits its limits ". EurekAlert. Posted: August 26, 2011. Available online:

    Sunday, September 11, 2011

    Black death study lets rats off the hook

    Rats weren’t the carriers of the plague after all. A study by an archaeologist looking at the ravages of the Black Death in London, in late 1348 and 1349, has exonerated the most famous animal villains in history.

    “The evidence just isn’t there to support it,” said Barney Sloane, author of The Black Death in London. “We ought to be finding great heaps of dead rats in all the waterfront sites but they just aren’t there. And all the evidence I’ve looked at suggests the plague spread too fast for the traditional explanation of transmission by rats and fleas. It has to be person to person – there just isn’t time for the rats to be spreading it.”

    He added: “It was certainly the Black Death but it is by no means certain what that disease was, whether in fact it was bubonic plague.”

    Sloane, who was previously a field archaeologist with the Museum of London, working on many medieval sites, is now attached to English Heritage. He has concluded that the spread of the 1348-49 plague, the worst to hit the capital, was far faster, with an impact far worse than had been estimated previously.

    While some suggest that half the city’s population of 60,000 died, he believes it could have been as high as two-thirds. Years later, in 1357, merchants were trying to get their tax bill cut on the grounds that a third of all property in the city was lying empty.

    Sloane spent nearly 10 years researching his book, poring over records and excavation reports. Many records have gone missing, while there was also a documentation shortfall as disaster overwhelmed the city. Names of those buried in three emergency cemeteries seem not to have been recorded.

    However, Sloane found a valuable resource in records from the Court of Hustings, of wills made and then enacted during the plague years. As the disease gripped – in October 1348 rather than the late summer others suggested, reaching its height in April 1349 – the numbers of wills soared as panic-striken wealthy citizens realised their deaths were probably imminent.

    On 5 February 1349 Johanna Ely, her husband already dead, arranged provision for her children, Richard and Johanna. She left them property, spelled out which beds and even pots and pans each was to receive, and placed them in the guardianship of her own mother. She was dead within 72 hours.

    It appeared to the citizens that everyone in the world might die. Richard de Shordych left goods and money to his son Benedict when he died in early March: his son outlived him by a fortnight.

    Money, youth, and formerly robust good health were no protection. Edward III’s own daughter, Joan, sailed for Spain with her trousseau, her dowry and her bridesmaids, to marry Pedro, heir to the throne of Castile. She would never see her wedding day as she died of the plague within 10 days of landing.

    John of Reading, a monk in Westminster, left one of the few witness accounts. He described deaths happening so fast there was “death without sorrow, marriage without affection, self-imposed penance, want without poverty, and flight without escape”.

    In Rochester, William of Dene wrote that nobody could be found to bury the dead, “but men and women carried the bodies of their own little ones to church on their shoulders and threw them into mass graves from which arose such a stink that it was barely possible for anyone to go past a churchyard”.

    Sloane estimates that people living near the cemetery at Aldersgate, which is now buried under Charterhouse Square, in Smithfield, would have seen a corpse carried past every five minutes at the height of the plague.

    As many wills were being made in a week as in a normal year. Usually these would only be activated months or years later: in the worst weeks of the plague there was barely time to get them written down. Many, like Johanna Ely, probably made their wills when they felt the first dreaded sweats and cramps of the disease. Others left property and the care of their children to people who then barely outlived them.

    The archaeology of the plague also reveals that most people, however, were buried with touching care, neatly laid out in rows, heads facing west, with far more bodies put in coffins than in most medieval cemeteries – but possibly through fear of infection.

    Only a few jumbled skeletons hint at burials carried out some time after death and decomposition; those cases probably arose because bodies were found later on in buildings where every member of the household had died.

    Sloane believes there was little difference in mortality rates between rich and poor, because they lived so closely packed together. The plague, he is convinced, spread from person to person in the crowded city.

    Mortality continued to rise throughout the bitterly cold winter, when fleas could not have survived, and there is no evidence of enough rats.

    Black rat skeletons have been found at 14th-century sites, but not in high enough numbers to make them the plague carriers, he said.

    In sites beside the Thames, where most of the city’s rubbish was dumped and rats should have swarmed, and where the sodden ground preserves organic remains excellently, few black rats have been found.

    Sloane wants to dig up Charterhouse, where he believes 20,000 bodies lie under the ancient alms houses and modern buildings, including the Art Deco block where the fictional character Hercule Poirot lives in the television series. And, if anyone finds a mass medieval rat grave, he would very much like to know.

    Past Horizons. 2011. "Black death study lets rats off the hook". Past Horizons. Posted: August , 2011. Available online:

    Saturday, September 10, 2011

    Horses Domesticated 9,000 Years Ago in Saudi Arabia

    Saudi Arabia has found traces of a civilization that was domesticating horses about 9,000 years ago, 4,000 years earlier than previously thought, the kingdom said.

    "This discovery shows that horses were domesticated in the Arabian Peninsula for the first time more than 9,000 years ago, whereas previous studies estimated the domestication of horses in Central Asia dating back 5,000 years, Ali al-Ghabban, vice-chairman of the Department of Museums and Antiquities, said at a news conference late Wednesday.

    The remains of the civilization were found close to Abha, in southwestern Asir province, an area known to antiquity as Arabia Felix.

    The civilization, given the name al-Maqari, used "methods of embalming that are totally different to known processes," Ghabban said.

    Among the remains found at the site are statues of animals such as goats, dogs, hawks, and a three foot-tall bust of a horse, Ghabban said.

    "A statue of an animal of this dimension, dating back to that time, has never been found anywhere in the world," Ghabban said.

    He added that archaeologists also found arrowheads, stone tools, weaving tools and mortars for pounding grain, reflecting the development of that civilization.

    The remains were found in a valley that was once a riverbed, at a time when the now-arid Arabian Peninsula was more humid and fertile, the official said.

    An international team of archaeologists published an article in January that suggested human beings could have been present on the Arabian Peninsula about 125,000 years ago.

    Discovery News. 2011. "Horses Domesticated 9,000 Years Ago in Saudi Arabia". Science Daily. Posted: August 25, 2011. Available online:

    Friday, September 9, 2011

    British Men May Have a Hunter-Gatherer Past

    British men may trace their lineage back to hunter-gatherers, not farmers as had previously been suspected.

    A new genetic lineage study finds that, contrary to previous research, British men do not descend from immigrant farmers who migrated west from the Near East around 10,000 years ago. Instead, the new study finds that a common Y-chromosome gene in today's British men traces back to hunter-gatherers who settled in Europe long before farming got popular.

    In a study first published online in August 2010 in the European Journal of Human Genetics, researchers from the Sorenson Molecular Genealogy Foundation in Utah reported that a certain genetic mutation on the Y chromosome (male sex chromosome) was most common in the southeast of Europe and much less prevalent on the British Isles and other northwestern regions. This southeast-northwest pattern matched the spread of the Linearbandkeramik, or Linear Pottery, culture, a Neolithic culture known for their pottery kitchen dishes.

    Another study, this one published in the journal PLoS Biologyin 2010, also argued that a group of people who carried a certain set of genes known as haplogroup R1b1b2 (R-M269) could trace their ancestry to the Neolithic expansion of farming cultures from the east. About 110 million European men are in this group.

    But the new paper, published in the journal Proceedings of the Royal Society B: Biological Sciences, uses a larger dataset of more than 10,000 Europeans, Near Easterners and West Asians. In this comprehensive dataset, the researchers found, the previously reported southeast-northwest gradient didn't appear. Multiple R-M269 subgroups are common in different parts of Europe, the researchers wrote, suggesting that various hunter-gatherer groups radiated outward from different areas to populate Europe.

    According to Dr Cristian Capelli, the Oxford geneticist who led the research, the study "resets" the debate on the peopling of Europe.

    "Our works overturns the recent claims of European Y chromosomes being brought into the continent by farmers," Capelli said in statement.

    Pappas, Stephanie. 2011. "British Men May Have a Hunter-Gatherer Past". Live Science. Posted: August 24, 2011. Available online:

    Thursday, September 8, 2011

    Himalaya village caught between culture and nature

    An ethnic community in Nepal's remotest Himalayan district, bordering Tibet, says it has been struggling to save its unique Buddhist culture from being uprooted by floods from a glacial lake.

    The locals of Halji village in Humla district of western Nepal practise the Drikung Kagyu school of Tibetan Buddhism, which has an 11th-Century monastery at its heart.

    They are very worried that the Rinchenling monastery - one of the oldest in Nepal and highly revered in Tibet - could be swept away or damaged by floods and mudslides caused by the outburst of a glacial lake on the mountain overlooking their village.

    For the past five years, Halji has been hit by glacial lake floods almost every summer and the last one, nearly two months ago, damaged two houses and swept away four horses.

    Several crop fields were washed away and many remain covered with sands, rendering them barren for many years to come.

    Villagers say the historic monastery now stands only around 15m away from the river bank that has been eroded by flood waters.

    They fear the next time the Tak Tsho lake bursts like it did this year, it may hit the 1,000 year-old sacred site.

    "It is our identity," said Kojuk Objang Tamang, the head of Halji village. "We cannot even imagine about our community without the monastery which is the base of our religious culture," he told the BBC.

    So strong is the community's belief in the monastery that they are convinced that it has saved them from the floods and mudslides so far.

    Mixed blessings

    "It is because of the blessings of the monastery that the village is hit by floods at day time only and so there is no loss of human lives because we can run to safety during daylight," said Mr Tamang. "Had it happened in the night when we were asleep, God knows how many of us would have been dead by now.

    Astrid Hovden of the University of Oslo, who has been conducting her PhD research in Halji, has witnessed how central the monastery is to the community of around 100 households.

    "At the night of the flood (last June), after the water level in the river started to get back to normal, the monks performed an elaborate ritual in the monastery to pray for the safety of their village.

    "Since the villagers became aware of the problem, they have invited important lamas (priests) from outside to perform rituals to protect their village."

    Prayers apart, the villagers have also done whatever they could to save the monastery and their settlement.

    Although almost all of them are uneducated, they have knocked on the doors of the prime minister's office in the capital Kathmandu, the local authority and the national planning commission.

    Those efforts had secured some funding, which they used to build defences using rocks and gabion wires to tame the flood waters.

    "Every family in our village worked free of cost for the construction of those infrastructures," says Tamang.

    Dicing with danger

    But villagers say that every year, the floods and mudslides hurtling down from the glacial lake - at a height of around 5,300m on the Gurla Mandhata mountain - become increasingly dangerous.

    "Our effort to save the village is proving to be no match for the force of the floods," said Mangal Lama, a social worker from the region.

    Mr Lama and other locals said they hiked up to the area where the Tak Tsho lake is located and found that it is hidden behind a hanging glacier.

    "We saw huge cracks on the glacier, and that explained why we used to hear big sounds around the same time in June every year before we were hit by floods.

    "Apparently, it appears that the huge pieces of ice sheet from the cracked parts of the glacier might have fallen into the glacial lake which then overflowed, causing floods and mudslides downstream."

    Some scientists say climate change has accelerated glacial meltdown in the Himalayas, creating many new glacial lakes and filling up existing ones to dangerous levels.

    Most of the 4,000 or so glaciers and their lakes in the Nepalese Himalayas are not monitored, like the one above Halji in Humla district.

    Nepal's National Adaptation Programme of Action, prepared under the United Nations climate convention, has rated the district's vulnerability to glacial lake outburst flood as "very low" - something which has been disputed.

    Mr Lama said some villagers are so frustrated that they are considering going to Tibet across the border to become refugees.

    "It takes five days walk to reach the nearest local authority of Nepal while Taklakot (the nearest Tibetan market) is only 12 hours away and moreover the villagers speak the Tibetan language and follow all traditions of Tibet."

    Locals say they cannot move the monastery and their settlement to a safe place.

    "The moment we move the monastery, its religious and historic value will drop to zero," says Tamang. "And that, in turn, means our century-old intact religious and cultural community will break and it will all be over."

    Khadka, Navin Singh. 2011. "Himalaya village caught between culture and nature". BBC News. Posted: August 23, 2011. Available online: