вторник, 9 июля 2019 г.

Key early steps for origin of life occur under a variety of conditions

Potential precursors to life on Earth form from a variety of complex mixtures, according to a team of scientists who say this could point to the development of building blocks crucial to forming genetic molecules for the origins of life on Earth.

Key early steps for origin of life occur under a variety of conditions
Scientists conducted a series of test meant to capture complex chemical mixtures like those that lightning strikes may
have created before life on Earth. The resulting chemistry may reveal an important step toward the origin of life
[Credit: Pixabay/AbelEscobar]

Genetic molecules provide the ability to store and replicate information and may have been critical for the origin of life, but it is unclear how they arose from complex chemical environments that existed on early Earth. New findings, published this week in the journal Scientific Reports, suggest the answer may start with nitrogen heterocycles, ringed molecules believed to be common on young Earth and elsewhere in the solar system. Several types of heterocycles serve as nucleobases, or subunits, of DNA and RNA, the genetic molecules used by life as we know it.

«One of the challenges of studying the origin of life is deciphering what reactions were key steps,» said Christopher House, professor of geosciences at Penn State. «Our work here identified the most likely next steps these molecules could and would take.»

A team of researchers found that nitrogen heterocycles may have served as building blocks toward life in a series of tests that generated complex chemical mixtures like those possibly created by lightning strikes passing through early Earth’s atmosphere. Dozens of different heterocycles produced similar primitive genetic precursors even when the atmospheric composition was varied in the study.

«The real surprises were that so many different such ringed molecules were found to be reactive and that they formed the same next step regardless of what simulated atmosphere we used,» said House, who also serves as director of the Penn State Astrobiology Research Center and the NASA Pennsylvania Space Grant Consortium.

The results support a hypothesis that simpler genetic structures could predate the formation of DNA and RNA and suggest that similar prebiotic reactions could happen elsewhere in the solar system.

Unlike previous studies, which have explored similar reactions in isolated conditions, the team used organically complex mixtures that better simulate early Earth chemistry not knowing whether the reactions would represent a constructive step toward life or a dead end.

In the study, the heterocycles reacted in the complex mixture to form chemically reactive side chains, structures that link heterocycles together and facilitate the formation of more complex molecules, the researchers said.

These modified heterocycles could serve as the subunit of peptide nucleic acids (PNAs), a proposed precursor to RNA. That they formed so readily in different atmospheric conditions supports the theory that PNAs could have formed on prebiotic Earth.

«Our findings hint at the possibility of PNA on the early Earth since we observed many robust synthetic pathways for some of its components,» said Mike Callahan, assistant professor of chemistry at Boise State University.

The findings also have implications for similar genetic precursors on other worlds.

«The organics reacting with the heterocycles and forming these side chains have also been identified in the interstellar medium, comets, and even Titan’s atmosphere,» said Laura Rodriguez, who led the research as a doctoral student studying geosciences at Penn State. «And since the reactions were robust in complex mixtures under a broad range of conditions, our results may have implications for the formation of PNAs beyond Earth.»

Author: A’ndrea Elyse Messer | Source: Pennsylvania State University [July 08, 2019]



Jurassic shift: Changing the rules of evolution

For more than 150 years, scientists have debated whether the success of organisms is mainly down to environmental factors such as climate change or whether — as advocated by Charles Darwin — interaction between species has a significantly more important role to play. A British-German study involving palaeobiologist Prof. Dr. Wolfgang Kießling from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) has now shown that the influence of environmental factors was considerably greater at the early stages of the evolution of animal life before becoming significantly less important 170 million years ago.

Jurassic shift: Changing the rules of evolution
Satellite image of an algal bloom of Emiliana huxleyi off the south west coast of England.
The calcified shells colour the water milky white [Credit: NASA]

The team investigated the fossil record of marine life over the past 400 million years. The ecological success of marine organisms, measured by the proliferation of the various species, was strongly dependent on suitable chemical and climate conditions until roughly the middle of the Jurassic period. During the Jurassic period, approximately 170 million years ago, the situation changed. Since then, it would appear that biological interactions have played the major role.
Why this sudden change and why at this particular time? ‘The answer probably lies with microscopic organisms, or plankton. The rise of planktonic algae with a calcified shell began in the Jurassic period. Gigantic quantities of these calcifying algae are still drifting in the ocean today and form calciferous sediment on the ocean floor after they die. The calcite helps to balance out acid. This facilitates the formation of calcified shells and allows organisms to use their energy differently,’ explains Professor Wolfgang Kießling.

Another explanation can be found in the organisms’ metabolism itself. On average, evolution made animals more and more active. Increased activity goes hand in hand with an improved physiological buffer. A coral is more at the mercy of the environment than a snail, for example.

A greater level of activity also means, however, an increased need for oxygen. Again, the algae appear to have had a crucial impact: Calcifying plankton have a higher sinking velocity which allows them to reach greater depths before they are eventually eaten by other organisms consuming oxygen. This increases the oxygenation of shallow waters. 170 million years ago, small algae had a genuinely revolutionary effect on the rules of the game for evolution, which still apply today.

The study is published in Nature Geoscience.

Source: University of Erlangen-Nuremberg [July 08, 2019]



Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia

An analysis of a 160,000-year-old archaic human molar fossil discovered in China offers the first morphological evidence of interbreeding between archaic humans and Homo sapiens in Asia.

Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia
The three-rooted lower molar anomaly in a recent Asian individual. Left: tooth sockets showing position
of accessory root; right: three-rooted lower first molar tooth [Credit: Christine Lee]

The study, which appears in the journal Proceedings of the National Academy of Sciences, centers on a three-rooted lower molar—a rare trait primarily found in modern Asians—that was previously thought to have evolved after H. sapiens dispersed from Africa. The new research points to a different evolutionary path.
«The trait’s presence in the fossil suggests both that it is older than previously understood and that some modern Asian groups obtained the trait through interbreeding with a sister group of Neanderthals, the Densiovans,» explains Shara Bailey, a professor of anthropology at New York University and the paper’s lead author.

In a previous study, published in Nature, Bailey and her colleagues concluded that the Denisovans occupied the Tibetan Plateau long before Homo sapiens arrived in the region.

Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia
Three-rooted lower second molar of Xiahe Denisovan individual
[Credit: The Max Planck Institute]

That work, along with the new PNAS analysis, focused on a hominin lower mandible found on the Tibetan Plateau in Baishiya Karst Cave in Xiahe, China in 1980.

The PNAS study, which also included NYU anthropologist Susan Antón and Jean-Jacques Hublin, director of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology, centered on the molar, with the aim of understanding the relationship between archaic humans who occupied Asia more than 160,000 years ago and modern Asians.

«In Asia, there have long been claims for continuity between archaic and modern humans because of some shared traits,» observes Bailey.

«But many of those traits are primitive or are not unique to Asians. However, the three-rooted lower molar trait is unique to Asian groups. Its presence in a 160,000-year-old archaic human in Asia strongly suggests the trait was transferred to H. sapiens in the region through interbreeding with archaic humans in Asia.»

Source: New York University [July 08, 2019]



Archaeologists begin first excavations of Boston’s Chinatown

Boston is literally digging its Chinatown. City archaeologist Joe Bagley on Monday launched the first excavations in Boston’s Chinatown, and he expects the dig to turn up artifacts that will shed new light on immigrants—not only those from China but also Syria, Ireland and England who sought new lives in Boston from 1840 to 1980.

Archaeologists begin first excavations of Boston's Chinatown
Volunteers dig and screen soil at the first historical excavation in Boston’s Chinatown
[Credit: Elise Amendola/AP]

Work began at a vacant lot near the ornate gate to the colorful neighborhood. It’s expected to continue until early autumn.
«We’re excited to conduct the first archaeological dig in Boston’s historic Chinatown,» said Mayor Marty Walsh. «Boston is a city of immigrants, and this is an important piece of Boston’s history.»

Archaeologists begin first excavations of Boston's Chinatown
Volunteers Lauryn Poe, left, and Charlie Deknatel, dig and screen soil at the first historical
excavation in Boston’s Chinatown[Credit: Elise Amendola/AP]

Over the years, Boston has unearthed hundreds of archaeological sites.
«Digging into Boston’s past is an exciting experience,» said Bagley, who has led recent excavations of an outhouse next to Paul Revere’s home and the boyhood home of civil rights activist Malcolm X.

Archaeologists begin first excavations of Boston's Chinatown
Volunteer Carole Mooney shows green glass as she screens soil at the first historical
excavation in Boston’s Chinatown [Credit: Elise Amendola/AP]

Carole Mooney, a volunteer, sifted through topsoil at the site and found pieces of porcelain, other pottery and brick. «It all helps tell the story,» she said.
Organizers say the property owner, residents of Chinatown, the Chinese Historical Society of New England and residents of Boston’s Syrian community are involved in the dig.

Archaeologists begin first excavations of Boston's Chinatown
City of Boston archaeologist Joe Bagley digs at the first historical excavation in Boston’s Chinatown
[Credit: Elise Amendola/AP]

In the late 1800s, the neighborhood—now popular with tourists for its restaurants and groceries—drew thousands of newcomers attracted by cheap housing and plentiful warehouse jobs in the adjacent Leather District.
Because the area was underwater until around 1830, researchers don’t expect to find much of interest prior to then, Mooney said.

Archaeologists begin first excavations of Boston's Chinatown
Sarah Keklak, archaeology lab manager for the city of Boston, sorts samples as the first
historical excavation takes place [Credit: Elise Amendola/AP]

But this is Boston, so you never know.

«At the Malcolm X dig, we found a cannonball,» she said. «It shouldn’t have been there—we still aren’t sure how it got there—but there it was.»

Author: William J. Kole | Source: The Associated Press [July 08, 2019]



4,000-year-old Canaanite warrior grave found in Sidon dig

New excavations at Sidon’s Freres archaeological site have unearthed an ancient grave of Canaanite warriors dating back to the 19th century BC, shedding light on some of the ancient southern port city’s history.

4,000-year-old Canaanite warrior grave found in Sidon dig
The new findings shed light on some of the ancient southern port city’s history
[Credit: The Daily Star/Mohammed Zaatari]

The dig, led by the British Museum under the supervision of Sidon’s Directorate General of Antiquities, has uncovered 171 burials on the Freres site over 21 years, according to the head of the British Museum’s delegation Claude Doumet-Serhal.
The well-preserved grave that was recently unearthed is an important discovery, as it provides information about the traditions of the ancient societies that lived along the Lebanese coast, Doumet-Serhal told The Daily Star Thursday.

4,000-year-old Canaanite warrior grave found in Sidon dig
An archaeologist works on the remains of two skulls discovered at the site
[Credit: Mahmoud Zayyat/AFP/Getty Images]

The grave housed the bodies of two adult male warriors, who were found buried with daggers and bronze belts that had been carefully placed near them. The feet of sheep or goats had been placed by the warriors’ feet, meant to accompany them in the afterworld.
Doumet-Serhal said the daggers were not used for fighting, but were significant because they showed the warriors belonged to the society’s elite: “The Canaanites did not bury in such a way unless the dead belonged to the aristocratic and elite class of the Canaanite society.”

4,000-year-old Canaanite warrior grave found in Sidon dig
Bronze dagger in situ [Credit: Mahmoud Zayyat/AFP/Getty Images]

DNA taken previously from other Canaanites graves at Freres compared to the DNA of 100 Lebanese showed 95 percent were of Canaanite descent, Doumet-Serhal said, adding, “We were never divided. We were all Canaanites, then we were Phoenicians, then the Romans came, then the Byzantines, then the Arabs.”
Excavations at the site take place for two months each summer, with this year’s dig set to end next week.

4,000-year-old Canaanite warrior grave found in Sidon dig
The find was made at an archaeological dig in Sidon in southern Lebanon
[Credit: Mahmoud Zayyat/AFP/Getty Images]

Doumet-Serhal said she hoped excavations would resume next year, as the findings would be included in Sidon’s historical museum when it opens to the public. Doumet-Serhal said the museum would feature artifacts on its first floor, and visitors could visit the dig on the ground floor.
In 2014, Sidon began construction of a museum that would preserve and showcase ruins from the various civilizations that lived in the city over a period of 6,000 years. It is unclear when the museum will open.

4,000-year-old Canaanite warrior grave found in Sidon dig
Aerial view of the Freres archaeological site in Sidon in southern Lebanon
[Credit: Mahmoud Zayyat/AFP/Getty Images]

“The belt and the daggers excavated will be placed in this Sidon museum next to all the pieces and artifacts discovered in this site over the course of 21 years,” Doumet-Serhal said.

Authors: Mohammed Zaatari & Sahar Houri | Source: The Daily Star [July 08, 2019]



Grazing animals drove domestication of grain crops

Many familiar grains today, like quinoa, amaranth, and the millets, hemp, and buckwheat, all have traits that indicate that they coevolved to be dispersed by large grazing mammals. During the Pleistocene, massive herds directed the ecology across much of the globe and caused evolutionary changes in plants. Studies of the ecology and growing habits of certain ancient crop relatives indicate that megafaunal herds were necessary for the dispersal of their seeds prior to human intervention. Understanding this process is providing scientists with insights into the early domestication of these plants.

Grazing animals drove domestication of grain crops
Large grazing animals have a strong selective force on plants, certain plants have evolved traits to thrive on pastoral
landscapes. Spengler and Mueller theorize that yak herding may have helped drive buckwheat domestication
in the southern Himalaya. This lone yak in the Lhasa region of Tibet is a significant evolutionary force
on the plant communities around where it grazes [Credit: Robert Spengler]

The domestication of small-seeded annuals involved an evolutionary switch from dispersal through animal ingestion to human dispersal. Those are the findings of a new study by Robert Spengler, director of the Paleoethnobotany Laboratories at the Max Planck Institute for the Science of Human History, and Natalie Mueller, a National Science Foundation fellow at Cornell University, published in Nature Plants.

Spengler and Mueller demonstrate, by looking at rangeland ecology and herd-animal herbivory patterns, that the progenitors of small-seeded crops evolved to be dispersed by megafaunal ruminants. Although today the wild varieties of these species grow in small, isolated patches, the researchers illustrate that heavy grazing of these plants by herd animals causes dense patches to form near rivers or other areas that the animals frequent.

In ancient times, these dense patches of plants could have easily been harvested, just like modern farmers’ fields — explaining how and why ancient people might have focused on these specific plants. This study provides an answer for this long-standing mystery of plant domestication.

Small-seeded crops are products of another age

During the mid-Holocene (7,000-5,000 years ago), in ecologically rich river valleys and grasslands all around the world, people started to cultivate small plants for their seed or grain. Wheat, barley, and rice are some of the earliest plants to show signs of domestication and scientists have extensively studied the domestication process in these large-seeded cereal crops.

Grazing animals drove domestication of grain crops
Cattle herding in the mountains of Central Asia leads to the formation of dense stands of plants that have specific
 adaptive traits to heavy grazing. As Spengler and Mueller point out, these homogenous plant patches or fields
 are often composed to the ancient relatives of modern grain crops [Credit: Robert Spengler]

Researchers know significantly less about the domestication of small-seeded grain crops, such as quinoa, amaranth, buckwheat, the millets, and several now-lost crops domesticated in North America. The wild ancestors of these crops have small seeds with indigestible shells or seed coats. Today, these wild plants exist in small fragmentary patches dispersed across huge areas — the fact that they do not grow in dense clusters, like the ancestors of wheat and rice, would seem to have made these crop ancestors unappealing targets for foragers. The small seed sizes and hard seed shells, combined with the lack of dense wild populations, led many researchers to argue that they must have been a famine food.

Foraging enough wild seeds from these varieties to grind into flour to bake a loaf of bread would take weeks, especially for rarer or endangered crop ancestors. So why did early foragers focus so heavily on these plants and eventually adopt them as crops?

Spengler and Mueller present a new model, suggesting that when humans first encountered these plants, they would have grown in dense stands created by grazing megafauna, making them easy to harvest. As humans began to cultivate these plants, they took on the functional role of seed dispersers, and eventually the plants evolved new traits to favor farming and lost the old traits that favored being spread by herd animals. The earliest traits of domestication, thinning or loss of indigestible seed protections, loss of dormancy, and increased seed size, can all be explained by to the loss of the ruminant dispersal process and concomitant human management of wild stands.

A novel model for the domestication of small-seeded grain crops

Spengler and Mueller have been interested in plant domestication since graduate school, when they studied under Dr. Gayle Fritz, one of the first scholars to recognize the importance of the American Midwest as a center of crop domestication. Despite decades of research into the nature of plant domestication in North America, no one recognized that the true key was the massive bison herds.

Grazing animals drove domestication of grain crops
A bison trail through a dense wild field of little barley. This plant is one of the progenitors
of a North American lost crop. Heavy bison grazing activity seems to result in dense
fields of this plant in the wild, which would have been easy for early foragers
to collect the seeds from [Credit: Natalie Mueller]

The plants that were domesticated, what Mueller calls the «Lost Crops,» would have been dispersed by bison in large swaths, making them easy to collect by ancient people and perhaps encouraging these communities to actively plant them themselves. When Europeans exterminated the herds, the plants that relied on these animals to disperse their seeds began to diminish as well. Because the wild ancestors of these lost crops are rare today and the bison herds are effectively extinct, researchers have overlooked this important coevolutionary feature in the domestication process.
However, this process is not unique to the American Midwest and the researchers suggest that there may be links between buckwheat domestication and yak herding in the Himalaya and amaranth domestication and llama herding in the Andes. The authors have identified parallel patterns in rangeland ecology studies, noting that heavy herd animal herbivory can homogenize vegetation communities. For example, heavy pastoralist grazing in the mountains of Central Asia causes many plants to die, but certain plants with adaptations for dispersal by animals thrive. The depositing of plant seeds in nutrient rich dung leads to ecological patches, often called hot spots, that foragers can easily target for seed collecting.

For over a century, scholars have debated why early foragers targeted small-seeded annuals as a major food source (eventually resulting in their domestication). Today, the progenitors of many of these crops have highly fragmentary populations and several are endangered or extinct. Likewise, without large dense homogenous stands of these plants in the wild, such as what exists in the wild for the progenitors of large-seeded cereal crops, it would have been impossible to harvest their seeds.

The conclusions that Spengler and Mueller draw help explain why people targeted these plants and were able to domesticate them. «Small-seeded annuals were domesticated in most areas of the world,» explains Spengler. «So the ramifications of this study are global-scale. Scholars all over the world will need to grapple with these ideas if they want to pursue questions of domestication.»

Spengler and Mueller are continuing their research into the role that grazing animals played in plant domestication. «Currently, we’re studying the ecology of fields where modern herd animals graze as proxies to what the ecology would have looked like during the last Ice Age, when large herds of bison, mammoths, and wooly horses dictated what kinds of plants could grow across the American Midwest and Europe,» explains Spengler. «We hope these observations will provide even greater insight into the process of domestication all over the world.»

Source: Max Planck Institute for the Science of Human History [July 08, 2019]



Giant Bugs Many types of bacteria are shaped like microscopic…

Giant Bugs

Many types of bacteria are shaped like microscopic balls or rods, like the ones on the left of this image. But break a gene called murA – which builds the stiff bacterial cell wall – and something strange starts to happen. Within 24 hours, the bugs have grown into bizarre giant cells (right) that look nothing like the neat rods that they normally resemble. Under most circumstances, having a faulty murA should be enough to kill the cells. But researchers have worked out a clever way of keeping them alive long enough to see its strange effects. Many antibiotics are designed to target parts of the cell wall, yet bacteria are increasingly evolving resistance to these life-saving therapies. By figuring out how these bugs survive without such an essential cell wall gene, scientists hope to find ways of combating antibiotic resistance or developing more effective new drugs in the future.

Written by Kat Arney

You can also follow BPoD on Instagram, Twitter and Facebook

Archive link

Powering the Extreme Jets of Active Galaxies

Black-hole-powered galaxies called blazars have powerful jets that are thought to be fortuitously aimed directly toward Earth. Astronomers have used multi-band observations, from the gamma-ray to the radio, to study the powerful jets and their driving sources. Credit: NASA; M. Weiss/CfA

An active galaxy nucleus (AGN) contains a supermassive black hole that is vigorously accreting material. It typically ejects jets of particles that move at close to the speed of light, radiating across many wavelengths, in particular the X-ray, in processes are among the most energetic phenomena in the universe. The jets are often also highly collimated and extend far beyond their host galaxy, and if they happen to be pointed along our line of sight they are the most spectacular class of this phenomenon: blazars.

A few years ago astronomers noticed that some types of blazars have jet powers that appear to exceed the power provided by the accretion. Two ideas were put forward to explain the difference: the jets are also extracting power from the spin of the black hole or from the magnetic flux around the object. How either process happens – if indeed they do happen — is hotly debated, but one popular line of argument asserts that the processes are somehow related to the mass of the supermassive black hole, with the most massive cases (more than a hundred million solar-masses) being the most anomalous. Recently the Fermi Gamma-Ray Space Telescope detected gamma-rays (even more energetic photons than X-rays) coming from jets in a class of galaxies called Seyferts, spiral galaxies with relatively small supermassive black hole masses, typically about ten million solar-masses. Astronomers speculated that these relatively low-mass yet powerful emission engines might provide keys to sorting out the various sources of jet power.

CfA astronomer Mislav Balokovic and his colleagues completed a multi-wavelength study of the bright blazar-like Seyfert galaxy PKSJ1222+0413 and included data from the gamma-ray to the radio, both archival and new observations, including new results from the NuSTAR space observatory They then undertook a complete modeling of this source, the most distant one of its type known — its light has been traveling towards us for about eight billion years. They detected the pronounced signature of an accretion disk, and estimated the mass of the supermassive black hole from the widths and strengths of the emission lines to be about two hundred million solar-masses, about ten times higher than most other Seyferts of its type. The jet luminosity is only about half the accretion luminosity, unlike cases like galaxies whose jet power exceeds the accretion. But the object nonetheless clearly falls into a transition regime for jet strengths, enabling future studies to study in more detail the origins of jet power both Seyfert galaxies and in blazars.


«The Relativistic Jet of the γ-ray Emitting Narrow-Line Seyfert 1 Galaxy PKS J1222+0413,» Daniel Kynoch, Hermine Landt, Martin J. Ward, Chris Done, Catherine Boisson, Mislav Balokovic, Emmanouil Angelakis, and Ioannis Myserlis, MNRAS 487, 181, 2019.

Archive link

New Method May Resolve Difficulty in Measuring Universe’s Expansion

Artist’s impression of the explosion and burst of gravitational waves emitted when a pair of superdense neutron stars collide. New observations with radio telescopes show that such events can be used to measure the expansion rate of the Universe. Credit: NRAO/AUI/NSF. Hi-Res File

Radio observations of a jet of material ejected in the aftermath of the neutron-star merger were key to allowing astronomers to determine the orientation of the orbital plane of the stars prior to their merger, and thus the «brightness» of the gravitational waves emitted in the direction of Earth. This can make such events an important new tool for measuring the expansion rate of the Universe. Credit: Sophia Dagnello, NRAO/AUI/NSF. Hi-Res File

Astronomers using National Science Foundation (NSF) radio telescopes have demonstrated how a combination of gravitational-wave and radio observations, along with theoretical modeling, can turn the mergers of pairs of neutron stars into a “cosmic ruler” capable of measuring the expansion of the Universe and resolving an outstanding question over its rate.

The astronomers used the NSF’s Very Long Baseline Array (VLBA), the Karl G. Jansky Very Large Array (VLA) and the Robert C. Byrd Green Bank Telescope (GBT) to study the aftermath of the collision of two neutron stars that produced gravitational waves detected in 2017. This event offered a new way to measure the expansion rate of the Universe, known by scientists as the Hubble Constant. The expansion rate of the Universe can be used to determine its size and age, as well as serve as an essential tool for interpreting observations of objects elsewhere in the Universe.

Two leading methods of determining the Hubble Constant use the characteristics of the Cosmic Microwave Background, the leftover radiation from the Big Bang, or a specific type of supernova explosions, called Type Ia, in the distant Universe. However, these two methods give different results.

“The neutron star merger gives us a new way of measuring the Hubble Constant, and hopefully of resolving the problem,” said Kunal Mooley, of the National Radio Astronomy Observatory (NRAO) and Caltech.

The technique is similar to that using the supernova explosions. Type Ia supernova explosions are thought to all have an intrinsic brightness which can be calculated based on the speed at which they brighten and then fade away. Measuring the brightness as seen from Earth then tells the distance to the supernova explosion. Measuring the Doppler shift of the light from the supernova’s host galaxy indicates the speed at which the galaxy is receding from Earth. The speed divided by the distance yields the Hubble Constant. To get an accurate figure, many such measurements must be made at different distances.

When two massive neutron stars collide, they produce an explosion and a burst of gravitational waves. The shape of the gravitational-wave signal tells scientists how “bright” that burst of gravitational waves was. Measuring the “brightness,” or intensity of the gravitational waves as received at Earth can yield the distance.

“This is a completely independent means of measurement that we hope can clarify what the true value of the Hubble Constant is,” Mooley said.

However, there’s a twist. The intensity of the gravitational waves varies with their orientation with respect to the orbital plane of the two neutron stars. The gravitational waves are stronger in the direction perpendicular to the orbital plane, and weaker if the orbital plane is edge-on as seen from Earth.

“In order to use the gravitational waves to measure the distance, we needed to know that orientation,” said Adam Deller, of Swinburne University of Technology in Australia.

Over a period of months, the astronomers used the radio telescopes to measure the movement of a superfast jet of material ejected from the explosion. “We used these measurements along with detailed hydrodynamical simulations to determine the orientation angle, thus allowing use of the gravitational waves to determine the distance,” said Ehud Nakar from Tel Aviv University.

This single measurement, of an event some 130 million light-years from Earth, is not yet sufficient to resolve the uncertainty, the scientists said, but the technique now can be applied to future neutron-star mergers detected with gravitational waves.

“We think that 15 more such events that can be observed both with gravitational waves and in great detail with radio telescopes, may be able to solve the problem,” said Kenta Hotokezaka, of Princeton University. “This would be an important advance in our understanding of one of the most important aspects of the Universe,” he added.

The international scientific team led by Hotokezaka is reporting its results in the journal Nature Astronomy.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Media Contact:

Dave Finley, Public Information Officer
(575) 835-7302

Archive link

Hundreds of sharks and rays tangled in plastic

Hundreds of sharks and rays have become tangled in plastic waste in the world’s oceans, new research shows.

Hundreds of sharks and rays tangled in plastic
An adult shortfin mako shark entangled in fishing rope (biofouled with barnacles) in the Pacific Ocean,
causing scoliosis of the back [Credit: Daniel Cartamil]

University of Exeter scientists scoured existing published studies and Twitter for shark and ray entanglements, and found reports of more than 1,000 entangled individuals.

And they say the true number is likely to be far higher, as few studies have focussed on plastic entanglement among shark and rays.

The study says such entanglement — mostly involving lost or discarded fishing gear — is a «far lesser threat» to sharks and rays than commercial fishing, but the suffering it causes is a major animal welfare concern.

«One example in the study is a shortfin mako shark with fishing rope wrapped tightly around it,» said Kristian Parton, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

«The shark had clearly continued growing after becoming entangled, so the rope — which was covered in barnacles — had dug into its skin and damaged its spine.

«Although we don’t think entanglement is a major threat to the future of sharks and rays, it’s important to understand the range of threats facing these species, which are among the most threatened in the oceans.

«Additionally, there’s a real animal welfare issue because entanglements can cause pain, suffering and even death.»

Co-author Professor Brendan Godley, co-ordinator of the university’s marine strategy, added: «Due to the threats of direct over-fishing of sharks and rays, and ‘bycatch’ (accidental catching while fishing for other species), the issue of entanglement has perhaps gone a little under the radar.

Hundreds of sharks and rays tangled in plastic
Hundreds of sharks and rays have become tangled in plastic waste in the world’s oceans,
new research shows [Credit: Martin Stelfox]

«We set out to remedy this. Our study was the first to use Twitter to gather such data, and our results from the social media site revealed entanglements of species — and in places — not recorded in the academic papers.»

The review of academic papers found reports of 557 sharks and rays entangled in plastic, spanning 34 species in oceans including the Atlantic, Pacific and Indian. Almost 60% of these animals were either lesser spotted dogfish, spotted ratfish or spiny dogfish.

On Twitter, the researchers found 74 entanglement reports involving 559 individual sharks and rays from 26 species including whale sharks, great whites, tiger sharks and basking sharks.

Both data sources suggested «ghost» fishing gear (nets, lines and other equipment lost or abandoned) were by far the most common entangling objects. Other items included strapping bands used in packaging, polythene bags and rubber tyres.

The study identified factors that appear to put certain species more at risk:

— Habitat — sharks and rays in the open ocean appear more likely to get entangled, as do those living on the sea floor, where materials such as nets loaded with dead fish sink and attract predators, which in turn get stuck.

— Migration — species that cover long distances appear at more at risk of encountering plastic waste.

— Body shape — sharks seem to be at greater risk than rays. Species with unusual features — such as manta rays, basking sharks and sawfish — are also at more risk.

The study says more research is needed, and the researchers have worked with the Shark Trust to create an online report form to gather data on entanglements: https://recording.sharktrust.org/entanglement/record

The study has been published in the journal Endangered Species Research.

Source: University of Exeter [July 04, 2019]



The global tree restoration potential

Restoration of the Earth’s forests is the world’s most effective solution to climate change available today and has the potential to capture two thirds of man-made carbon emissions, finds landmark research by the Crowther Lab, published today in the journal Science.

The global tree restoration potential
Reforestation would be the most effective method to combat climate change
[Credit: Vershinin-M/iStock]

The study is the first to quantify how many trees the Earth can support, where they could exist and how much carbon they could store. It finds that there is potential to increase the world’s forest land by a third without affecting existing cities or agriculture, regrowing trees over an area the size of the United States or larger than Brazil.

Once mature, these new forests could store 205 billion tonnes of carbon, about two thirds of the 300 billion tonnes of extra carbon that exists in atmosphere as a result of human activity since the Industrial Revolution.

The study, led by Dr. Jean-Francois Bastin, also suggests that there is further potential to regrow trees in croplands and urban areas, highlighting the scope for agroforestry and city trees to play a major role in tackling climate change.

But the research paper, The global tree restoration potential, warns that the need for action is urgent: the climate is already changing and every year reduces the area of land that can support new forests. Even if global warming is limited to 1.5°C, the area available for forest restoration could be reduced by a fifth by 2050.

Professor Tom Crowther, senior author of the study said: «We all knew restoring forests could play a part in tackling climate change, but we had no scientific understanding of what impact this could make. Our study shows clearly that forest restoration is the best climate change solution available today and it provides hard evidence to justify investment. If we act now, this could cut carbon dioxide in the atmosphere by up to 25%, to levels last seen almost a century ago.

«However, it will take decades for new forests to mature and achieve this potential. It is vitally important that we protect the forests that exist today, pursue other climate solutions, and continue to phase out fossil fuels from our economies in order to avoid dangerous climate change.»

The Crowther Lab is a group of multi-disciplinary scientists studying the ecological processes that influence climate change, based at ETH Zürich, the world’s leading University in Earth and Environmental Sciences. Its study provides the first quantitative assessment of the feasibility of global forest restoration targets.

Research provides benchmark for a global action plan

Forests have always been considered an option for capturing atmospheric carbon, but it has never been clear what impact this could have at a global scale. This is because, until now, there has been no quantitative assessment of how much tree cover might be possible under current or future climate conditions.

The global tree restoration potential
Figure A shows the total land available that can support trees across the globe (total of current forested areas
and forest cover potential available for restoration [Credit: ETH Zurich/Crowther Lab]

The future scenarios proposed by the UN’s Intergovernmental Panel on Climate Change propose that limiting climate change to 1.5°C will require up to an extra billion hectares of forest by 2050, even while radically reducing emissions from energy, transport and so on. The new study allows this claim to be evaluated for the first time, showing where these trees could be restored and how much carbon they can capture. It confirms that this scenario projection is «undoubtedly achievable under the current climate».

Currently there are 5.5 billion hectares of forest (defined by the UN Food and Agriculture Organisation as land with at least 10% tree cover and without human activity), with a total 2.8 billion hectares of tree canopy cover.

The Crowther Lab finds that forests could be regrown on 1.7-1.8 billion hectares of land in areas with low human activity that are not currently used as urban or agricultural land, adding 0.9 billion hectares of tree canopy. Importantly, these are not areas that would naturally be grasslands or wetlands, but degraded ecosystems that would naturally support some level of tree cover.

If cropland and urban areas were included the study finds that forests could be regrown on a further 1.4 billion hectares of land, adding 0.7 billion hectares of tree canopy.

Dr Jean-François Bastin, the lead author of the study, said: «Our study provides a benchmark for a global action plan, showing where new forests can be restored around the globe. Action is urgent and governments must now factor this into their national strategies to tackle climate change.»

The study finds that more than half the potential to restore trees can be found in just six countries: Russia (151 million hectares); USA (103 million); Canada (78 million); Australia (58 million); Brazil (50 million); and China (40 million).

It also highlights major inconsistencies in the targets of several global restoration initiatives and warns that better country-level forest accounting is critical for developing effective forest management and restoration strategies.

At the start of 2019, 48 countries had signed up to the Bonn Challenge, which aims to restore 350 million hectares of forest by 2030. However, the study finds that over 43% of these countries have committed to restore less than half the area that can support new forests while 10% have committed to restoring considerably more land than is suitable for forest growth.

Climate models wrong in forecasting more tree cover in warming world

The study also warns that some existing climate models are wrong in expecting climate change to increase global tree cover. It finds that there is likely to be an increase in the area of Northern «Boreal» forests in regions such as Siberia, where tree cover averages 30-40%. However, this would be outweighed by losses in dense tropical forests, which typically have 90-100% tree cover.

The global tree restoration potential
Figure B shows the land available for forest restoration (excluding deserts, agricultural and urban areas;
current forestland not shown) [Credit: ETH Zurich/Crowther Lab]

Prof, Crowther added: «Although government action is essential to make the most of this opportunity, this is a climate solution we can all get involved in and make a tangible impact. You can grow trees yourself, donate to forest restoration organizations or just invest your money responsibly in businesses which are taking action on climate change.»

René Castro, Assistant Director-General, FAO, commented on the paper: «Forests are one of our biggest allies in combatting climate change with measurable results. Deforestation not only contributes to an alarming loss of biodiversity, but limits our ability to store carbon in the trees, undergrowth and soil. We now have definitive evidence of the potential land area for re-growing forests, where they could exist and how much carbon they could store.»

Ms. Christiana Figueres, Founding Partner, Global Optimism and Former Executive Secretary, UN Climate Convention, also commented: «Finally an authoritative assessment of how much land we can and should cover with trees without impinging on food production or living areas. A hugely important blueprint for governments and private sector».

Will Baldwin-Cantello, Global lead on Forests at WWF, said: «Our forests are the world’s biggest natural ally in the fight against climate change but without them, we will lose the fight to keep global warming below 1.5 C. That’s why it’s crucial that we act to restore forests whilst drastically cutting our global carbon emissions. This new research demonstrates how much natural capacity our planet has to grow and sustain additional forest; now, the challenge is to understand how and where we can accelerate this implementation, whilst still feeding our growing global population.

«Tackling the climate crisis and restoring our forests requires unprecedented levels of co-operation and support at both a local and global level, supported by initiatives such as Trillion Trees that are accelerating delivery on the ground. We have the solutions at our fingertips; we just need the global political will to fight for our world.»

Restoration of the Earth’s forests is the world’s most effective solution to climate change available today 
and has the potential to capture two thirds of man-made carbon emissions, finds landmark research 
by the Crowther Lab [Credit: Crowther Lab/Brodie Lea]

A tool on the Crowther Lab website enables users to look at any point on the globe, and identify the areas for restoration and learn which native tree species exist there. It also offers lists of forest restoration organizations. Furthermore, Crowther Lab are supporting the creation of a global coalition that will bring targeted innovation to the opportunities and challenges identified by the Report.


This is the first study to link direct tree measurements to environmental characteristics to provide quantitative, spatially explicit global estimates of potential tree cover. This was made possible because of a unique global dataset of forest observations and the free mapping software of Google Earth Engine.

Researchers analyzed tree cover in protected forest areas largely unaffected by human activity across the Earth’s ecosystems, from arctic tundra to equatorial rainforest, studying nearly 80,000 high resolution satellite photographs. They used this to approximate the natural level of tree cover in each ecosystem.

In Google Earth Engine, they then used machine learning to identify 10 soil and climate variables that determine tree cover in each ecosystem and generate a predictive model to map potential tree cover worldwide under current environmental conditions in areas with minimal human activity.

They used three well-known climate models to update changes to the variables in order to project tree cover capacity for 2050.

Source: Crowther Lab, ETH Zurich [July 04, 2019]



Argentine palaeontologists discover giant prehistoric condor in Buenos Aires

The team of the Paleontological Museum of San Pedro found an extinct condor that exceeded 3.50 meters in length with its wings open, much more than the current Andean condor. Its fossil remains are about 10 thousand years old.

Argentine palaeontologists discover giant prehistoric condor in Buenos Aires
The current Andean condor has an average wingspan of about 3 meters while this extinct condor
had an extension of more than three and a half meters [Credit: Agency CTyS-UNLaM]

The discovery occurred 12 kilometers south of the Buenos Aires city of San Pedro. Dr. Federico Agnolin, researcher at the Argentine Museum of Natural Sciences (MACN), Felix de Azara Foundation and CONICET, said that «it is an exceptional finding, since it is the record of a new species of giant bird that flew over the province of Buenos Aires at the end of the Pleistocene».

The current Andean condor has an average wingspan of about 3 meters while this extinct condor had an extension of more than three and a half meters.

«The ulna and radius found, belonging to the right wing, are much more robust than the Vultur gryphus, popularly known as the Andean condor, so we estimate that its body mass was much higher, although the study has just begun», Agnolin added to the Agency CTyS-UNLaM.

The director of the Museum of San Pedro Jose Luis Aguilar commented that «the weight of this great bird was probably between 18 and 20 kilos, while the Andean condor has a body mass between 12 and 15 kilos.»

Argentine palaeontologists discover giant prehistoric condor in Buenos Aires
Credit: Agency CTyS-UNLaM

The discovery was made by a team from the San Pedro Museum made up of Jose Luis Aguilar, Julio Simonini, Javier Saucedo, Matias Swistun, Bruno Zarlenga and Bruno Rolfo in the La Paloma establishment of the cereal company Ramon Rosa SA. «In that place, the rains generate cuts in the ground, which allows us to observe ancient sediments from the Lujanenese Age,» Aguilar said.

This gigantic new condor (which still has no name) lived accompanied by other scavenger birds such as giant caranchos, vultures and jotes. However, since birds have hollow bones, there are very few remains preserved.

Dr. Agnolin affirmed that he has just begun the study of this new specimen. «It is a relevant finding and it shows us that the condors were much more diverse at that time and that they also inhabited the Pampean region, while at present they can be seen in the Andean region, in the north of Argentina and, even, up to in the province of Cordoba».

Director Jose Luis Aguilar revealed to the Agency CTyS-UNLaM that «together with the remains of the giant condor, its was discovered the upper jaw of a juvenile peccary, that is, of a very small piglet, and the pelvis of a turtle».

Researchers Nicolas Chimento from MACN and German Gasparini from the La Plata Museum collaborated to identify the remains of these two animals found near the condor.
Aguilar said that these two animals could have been part of the diet of the giant condor: «We hope to confirm it when they finish analyzing the remains under the microscope; we see that the surface of the remains of the peccary and the turtle differs in appearance with that of the bones of the condor, which is why we believe that it has been eroded by the gastric juices of the bird».

In the presentation of this finding, the Museum of San Pedro will feature a life-size sculpture of this giant condor. The work was made by paleoartist Miguel Lugo, from the city of Ramallo, commissioned by the Municipality of San Pedro.

Source: Agency CTyS-UNLaM [July 04, 2019]



Stone inscription with Tamil script found in China

A 13th century stone inscription with Tamil and Mandarin scripts has been discovered in Quanzhou, an ancient port city in Fujiyan province, South East China, and it has been deciphered by an amateur archaeologist in Dindigul.

Stone inscription with Tamil script found in China
Credit: TOI

Archaeologist V Narayanamoorthy said that many people with archaeology as a common interest led by Orissa Balu, historian and Tamil researcher, had formed a group. There are over 110 members from over 100 countries in this group whose common interest is Tamil. WhatsApp was their main mode of communication, except for KiKi Zhang, alias Niraimadi, a lecturer from Yunnan Minzu university in China. She sent messages through email, which reached Narayanamoorthy.

A Tamil enthusiast, she had discovered the ancient inscription in Fujian province, which is a coastal region, through which global trade flourished in ancient times.

Narayanamoorthy, who is also a paleographist, was able to decipher some of the wordings. He was able to date the inscription to the 13th century as it matched the palaeography pertaining to that period.

Some of the letters have been damaged. After careful reading, he was able to determine the lines of a poem praising the king.

“It starts with the words, Hari Om and goes on to praise the greatness of Lord Shiva and seeks his blessings for the king,’’ he said, though there were some grammatical errors in the inscription.

He said that lines like the first stanza of the poem had been found in copper and palm leaf manuscripts, found in many parts of Tamil Nadu. Many poems of this type have a common beginning and later talk of different topics, he said.

A similar stone inscription dating back to 1281 AD was discovered in the same city about 70 years ago, which had information about a temple for Lord Shiva being built in the region and it was called Kaneeswaram.

This stone inscription too may have some connection to the temple, said Naryanamoorthy.

“What is outstanding in this inscription is that the Tamil writings are on top and the mandarin letters, which have withered away, at the bottom,’’ he said.

Source: The Times of India [July 04, 2019]



The ancestor of the great white shark

Mackerel sharks (Lamniformes) are a group consisting of some of the most iconic sharks we know, including the mako shark (the fastest shark in the world), the infamous great white shark, and Megalodon, the biggest predatory shark that has ever roamed  the world’s oceans. An international team of researchers around Patrick L. Jambura from the University of Vienna found a unique feature in the teeth of these apex predators, which allowed them to trace back the origin of this group to a small benthic shark from the Middle Jurassic (165 mya).

The ancestor of the great white shark
A whole skeleton of the fossil shark Palaeocarcharias stromeri (total length approximately 1m)
from the Jura Museum Eichstatt [Credit: © Jurgen Kriwet]

Similar to humans, shark teeth are composed of two mineralized structures: a hard shell of hypermineralized tissue (in humans enamel, in sharks enameloid) and a dentine core. Depending on the structure of the dentine we distinguish between two different types: orthodentine and osteodentine.
Orthodentine has a very compact appearance and is similar to the dentine we can find in human teeth. In shark teeth, orthodentine is confined to the tooth crown. In contrast, the other dentine type is spongious in appearance and resembles real bone and therefore is called osteodentine. It can be found in the root, anchoring the tooth to the jaw and in some species also in the tooth crown where it supports the orthodentine.

Using high resolution CT scans, Patrick L. Jambura and his colleagues examined the tooth composition of the great white shark and its relatives and found a peculiar condition of the teeth of members of this group: the osteodentine of the roots intrudes into the crown and replaces the orthodentine there completely, making it the only type of dentine being present. This condition is not known from any other shark, which all possess orthodentine to some degree and thus it is confined to members of this group.

The ancestor of the great white shark
High resolution micro-CT images reveal the same unique tooth histology in great white sharks
and the 160 million years old shark Palaeocarcharias stromeri
[Credit: © Patrick L. Jambura]

Another species that was examined was the fossil shark Palaeocarcharias stromeri, which is well-represented by complete skeletons from the famous 150 million year old Solnhofen Plattenkalks of South Germany. The oldest find of this species is from the Middle Jurassic (165 million years ago) and it didn’t have much in common with today’s mackerel sharks.

Palaeocarcharias was a small sluggish benthic shark, not exceeding lengths of more than a metre, that seemingly hunted small fish in shallow waters. To this day, its affiliation has been a riddle to scientists, since its body shape resembles a carpet shark, while its fang-like teeth are similar to mackerel sharks.

The examination of the tooth microstructure yielded the presence of the same unique tooth composition that is found only in great white sharks and their relatives. The shared tooth histology is a strong indicator that this small inconspicuous shark gave rise to one of the most iconic shark lineages that includes giants like the extinct Megalodon or the living great white shark.

«Orthodentine is known for almost all vertebrates—from fish to mammals, including all modern sharks, except for the mackerel sharks. The discovery of this unique tooth structure in the fossil shark Palaeocarcharias strongly indicates that we found the oldest known ancestor of the great white shark and shows that even this charismatic giant shark started on a shoestring,» says Patrick L. Jambura.

The study was recently published in the journal Scientific Reports.

Source: University of Vienna [July 05, 2019]



Saving the secrets of the jars of Laos

In the mountains and plains of upper Laos sit thousands of stone jars, the only relics of an ancient civilisation possibly 2500 years old.

Saving the secrets of the jars of Laos
We actually know very little about the people who created the sites, or even when
 they placed the jars [Credit: Plain of Jars Research Project]

The jars, weighing up to 20 tonnes, appear to be part of a complex burial ritual, and were transported from quarries up to 10 kilometres away.

The Laos Plain of Jars joined the UNESCO World Heritage Register in July, with the committee describing the area as «the most prominent evidence of the Iron Age civilisation that made and used them until it disappeared».

It’s the third World Heritage property in Laos, after Vat Phou and Luang Prabang.

This is a global acknowledgement of the cultural and historic significance of this remarkable collection of sites, but we actually know very little about the people who created them, or even when they were placed.

No other evidence of this society exists beyond these mortuary sites; adding to the intrigue are a group of remarkably similar jar sites some 1200 kilometres away in Northeast India.

Using drones, ground penetrating radar, advanced chemical analysis and some good old-fashioned detective work, researchers are diligently putting together the missing pieces of this puzzle.

Saving the secrets of the jars of Laos
The team are using chemical analysis to narrow down potential quarry sites
[Credit: Shutterstock]

Dr. Louise Shewan, is an archaeological scientist and Centenary Fellow from the University of Melbourne and co-leads an Australian Research Council funded research team—along with Associate Professor Dougald O’Reilly from ANU, and Dr. Thonglith Luangkoth from the Laos Department of Heritage—that has been studying the Lao megalithic jar sites since 2016.

The Megaliths of Upper Laos

The team follows in the footsteps of pioneering archaeologist Dr. Madeleine Colani, a Frenchwomen who excavated the sites in the 1930s while employed by the École Française d’Extrême-Orient. Professor Shewan expresses «extreme admiration» for Dr. Colani and her work.

«She was diminutive in stature but a powerhouse who started this work at the age of 65,» she says. «With assistance from her younger sister, Eleonore, she researched, mapped and recorded many jar sites, collating individual attributes of the jars, and produced a two-volume piece of work.»

Dr. Shewan and Dr. O’Reilly have recently published a translation of Ms Colani’s work, Megaliths of Upper Laos, with up-to-date additions based on their more recent discoveries.

Each year the team spends several weeks identifying, mapping and excavating jar sites, and then many months analysing samples and data collected on these trips.

Saving the secrets of the jars of Laos
Dr Shewan excavating Burial 5 at Site 1 alongside student Joanna Koczur
[Credit: Plain of Jars Research Project]

Much of this work is done in the research labs in the School of Earth Sciences at the University of Melbourne.

On their most recent trip, in February this year, their co-supervised Ph.D. student, Nick Skopal and Lao colleagues found 15 new sites containing more than 100 jars. The sites are about a six-hour bus trip from the Laos capital, Vientiane.

«The sites are mesmerising,» Dr. Shewan says. «In 2017, we conducted research at a remote mountainous site that was especially mystical, heavily vegetated and cloaked in mist.»

Only a small number of the more than 100 known jar sites have been studied in depth. Some are inaccessible due to unexploded ordnance (UXO) left over from the Vietnam war era.

A clearing program is steadily opening up more sites, allowing the archaeologists to start building a picture of the people and society that created them.

What Teeth Can Tell Us

Human remains, including teeth, have been found buried around the jars, and so it is believed that these sites are associated with funerary practices.

Saving the secrets of the jars of Laos
Researchers are using drones, ground penetrating radar and advanced chemical analysis to try
and solve the puzzle of the jars [Credit: Plain of Jars Research Project]

Dr. Shewan says by analysing tooth enamel for ‘signatures’ or chemical residues preserved in the teeth like strontium or oxygen ratios, we can find out how the people used the landscape and where they obtained their food during childhood.

«Strontium isotope ratios vary in bedrock according to age and composition,» she says. «This signature is carried through to the soil via weathering, inherited by plants, and absorbed into teeth and bones of animals and humans through food and water.»

«Oxygen isotopes vary with climate, environment and geography. The oxygen isotope composition of skeletal tissue is related to that of ingested drinking water. Depending on the type of tooth analysed, we can use these signatures to get a snapshot of life from between birth to 16 years of age.»

The team are also using a similar kind of analysis to create chemical fingerprints for the stone jars, which can then be matched to potential quarry sites.

«Geochronology work has so far confirmed that the jars, some weighing more than 20 tonnes, were transported from quarry sites eight to 10 kilometres away,» says Dr. Shewan.

But we still don’t know how the jars were moved. «The actual mechanism of transport is another area of the research.»

Using an Eye in the Sky

As the work continues, the team are using drones to take photographs and video footage to create 3-D models and build a much richer map of jar sites than they can from the ground.

«We will use drone images to explore possible spatial patterning in jar placement, search for habitation areas as we don’t know where the population lived, measure distances between jar sites and observed quarry sites,» says Dr. Shewan. «And potentially find new sites under the forest canopy using drone-mounted lidar.»

Lidar technology uses a pulsed laser to measure distance from the drone and can penetrate canopied and inaccessible sites providing highly accurate details of the ground surface.

Remarkably, similar jars sites have been found over 1200 kilometres away in northeast India.

«The Assam sites are now gaining renewed interest given identified linguistic and genetic connections between Southeast Asia and Northeast India, and we hope to more fully explore these sites and the links between them in collaboration with our colleagues in India in the near future,» says Dr. Shewan.

Dr. Shewan, who has previously worked on prehistoric sites near the World Heritage site of Angkor Watt in Cambodia, is excited to see the Plain of Jars recognised in the same way.

«The World Heritage listing of the Lao megalithic jar sites will bring this unique cultural landscape to global awareness, leading to greater conservation of the sites. «It heightens the need to understand more about the culture that created the sites.»

See also: More mysterious jars of the dead unearthed in Laos

Author: Dr Daryl Holland | Source: University of Melbourne [July 08, 2019]




https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...