вторник, 14 мая 2019 г.

Local Branches Our neurons grow tiny branches called neurites…

Local Branches

Our neurons grow tiny branches called neurites to connect with other cells, stretching into networks which help us to process and respond to the outside world. There are billions of neurons in the brain so spotting patterns among them is sometimes as challenging as “seeing the wood for the trees”. Yet in this mouse brain, a technique called brainbow ‘paints’ neurons with different colours using fluorescent proteins, allowing a new microscopy technique called ChroMS to pick out individual cells among the busy branches. Capturing the scene in high resolution, we can take a virtual stroll through the nearby brain forest but also – later in the video – zoom out to trace the delicate shapes of individual neuronal ‘trees’ in the cerebral cortex. This powerful combination of techniques may reveal more about how different brain areas communicate, and how changes brought about by ageing or disease might alter these patterns.

Written by John Ankers

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Caption Spotlight (13 May 2019): Resistant Lava and ErosionThis…

Caption Spotlight (13 May 2019): Resistant Lava and Erosion

This image demonstrates the curious phenomenon called “topographic inversion.” The southern half of the picture is covered by a well-preserved lava flow. The flow stops just at the brink of descending a steep slope. Lava isn’t afraid of falling, so what happened here?

It is likely that the terrain to the north was once higher, and stopped the lava from flowing any further. Once the lava cooled, it protected the ground beneath it, while the softer rocks to the north continued to erode, “inverting” the topography so that what was once low-lying ground is now the top of a mesa.

NASA/JPL/University of Arizona

2019 May 14 Young Star Cluster Trumpler 14 from Hubble Image…

2019 May 14

Young Star Cluster Trumpler 14 from Hubble
Image Credit: NASA, ESA, and J. Maíz Apellániz (IoAoA Spain); Acknowledgment: N. Smith (U. Arizona)

Explanation: Why does star cluster Trumpler 14 have so many bright stars? Because it is so young. Many cluster stars have formed only in the past 5 million years and are so hot they emit detectable X-rays. In older star clusters, most stars this young have already died – typically exploding in a supernova – leaving behind stars that are fainter and redder. Trumpler 14 spans about 40 light years and lies about 9,000 light years away on the edge of the famous Carina Nebula. A discerning eye can spot two unusual objects in this detailed 2006 image of Trumpler 14 by the Hubble Space Telescope. First, a dark cloud just left of center may be a planetary system trying to form before being destroyed by the energetic winds of Trumpler 14’s massive stars. Second is the arc at the bottom left, which one hypothesis holds is the supersonic shock wave of a fast star ejected 100,000 years ago from a completely different star cluster.

∞ Source: apod.nasa.gov/apod/ap190514.html

Space Station science looking at Earth

ISS — International Space Station logo.

13 May 2019

In this edition of our bi-weekly update on European research run on the International Space Station, we’re taking our cue from the Living Planet Symposium – the largest conference on Earth Observation taking place this week in Milan, Italy – and focusing on our own planet.

Installing first Norais receiver on Columbus

Marine traffic

Many of the experiments that run on the International Space Station do not require astronaut intervention after the initial setup and periodic check-ups. The Norais-2 receiver was installed outside Europe’s Columbus laboratory during a spacewalk in 2015 and has been monitoring roughly 33 000 ships every day since then.

Much like an air traffic control system for marine vehicles, the Automatic Identification System (AIS) transmits a ship’s location, heading and speed over radio and is required for passenger ships and all ships above a certain weight in international waters.


Although the system was designed to be received at harbours, satellites can also receive the radio signals but interpreting the data requires some calculation. The receiver on the International Space Station is used to test satellite-based ship identification systems and improve algorithms. Global coverage of shipping would have implications for fighting piracy, ensure aquatic nature reserves are respected and help develop faster and better shipping routes that could reduce fuel consumption.

Sage monitoring

Another active instrument on the Space Station is SAGE-III, the latest in a line of NASA satellites that monitor ozone. The Station takes only 90 minutes to circle our planet, experiencing 16 sunrises, 16 sunsets, and sometimes moonrises or moonsets, every day. This affords the Stratospheric Aerosol and Gas Experiment – SAGE – a continuous view of the Sun or Moon through the atmosphere to measure the quantity of ozone, aerosols and other gases.

SAGE and Hexapod

The device that keeps SAGE continuously pointing in the right direction was developed by ESA for NASA. Dozens of times each day, the six-legged ‘Hexapod’ tracks the Sun and Moon in the few seconds of their setting and rising. The readings are complementing long-term monitoring by Europe’s Copernicus Sentinel missions: Sentinel-5P is the first in a series focusing on the atmosphere.

Atmosphere and space

Another instrument looking down from the Space Station is the Atmosphere–Space Interactions Monitor that is observing phenomena above thunderstorms. After a year in orbit the data is being analysed by scientists with results in preparation. More to follow later this week.

Moonrise seen from Space Station

Fresh arrivals, fresh science

Two days after its launch the SpaceX Dragon cargo spacecraft arrived at its docking port on the Earth-facing side of the International Space Station’s Harmony module at 15:32 GMT on May 6. Two of the European experiments in its cargo-hold, Photobioreactor and Nano Antioxidants,  were installed the next day and are running smoothly. The Mission Zero educational project featuring credit-card sized computers called AstroPi’s also finished running student codes and the results have been downloaded for schools around Europe.

Dragon arriving at Space Station

The Compacted Granular experiment also completed a campaign inside the Fluid Science Laboratory located in Columbus. The experiment focuses on the behaviour of granules without the disturbing influence of gravity. Its findings could be used to improve the industrial processing of bulk solids on Earth, such as coal dust, flour and grain.

ICE Cubes

The four ICE Cubes currently running inside Columbus are also active, investigating commercial computer boards’ resistance to space radiation, exobiology hardware and cybersecurity in space. In a creative twist on the theme of ‘Taking the pulse of our planet’, the fourth Cube is an inspiring art installation that is literally doing that, linking people’s heart rates with the International Space Station.

Related links:

Living Planet Symposium: https://www.esa.int/Our_Activities/Observing_the_Earth/Living_Planet_Symposium

Norais-2 receiver: https://www.ffi.no/no/Forskningen/forsvarssystemer/Sider/NORAIS-2.aspx

SAGE-III: https://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Research/Earth_s_atmosphere_new_results_from_the_International_Space_Station/(print)

Sentinel-5P: https://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-5P

Atmosphere–Space Interactions Monitor: https://www.esa.int/ASIM

Photobioreactor and Nano Antioxidants: https://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/The_latest_in_Space_Station_science

Mission Zero educational project: https://astro-pi.org/missions/zero/

Compacted Granular experiment: https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-11017/1813_read-26337/#/gallery/30236

Linking people’s heart rates: https://www.isunet.edu/admissions/8-news/561-hydras-go-to-space-two-isu-payloads-launch-to-the-international-space-station

European space laboratory Columbus: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Columbus

International Space Station (ISS): http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/International_Space_Station

Images, Video, Text, Credits: ESA/NASA/OHB.

Best regards, Orbiter.chArchive link

Shrinking Moon May Be Generating Moonquakes

NASA — Lunar Reconnaissance Orbiter (LRO) patch.

May 13, 2019

The Moon is shrinking as its interior cools, getting more than about 150 feet (50 meters) skinnier over the last several hundred million years. Just as a grape wrinkles as it shrinks down to a raisin, the Moon gets wrinkles as it shrinks. Unlike the flexible skin on a grape, the Moon’s surface crust is brittle, so it breaks as the Moon shrinks, forming “thrust faults” where one section of crust is pushed up over a neighboring part.

“Our analysis gives the first evidence that these faults are still active and likely producing moonquakes today as the Moon continues to gradually cool and shrink,” said Thomas Watters, senior scientist in the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington. “Some of these quakes can be fairly strong, around five on the Richter scale.”

Lee Lincoln Scarp at the Apollo 17 Landing Site

Video above: This visualization of Lee Lincoln scarp is created from Lunar Reconnaissance Orbiter photographs and elevation mapping. The scarp is a low ridge or step about 80 meters high and running north-south through the western end of the Taurus-Littrow valley, the site of the Apollo 17 Moon landing. The scarp marks the location of a relatively young, low-angle thrust fault. The land west of the fault was forced up and over the eastern side as the lunar crust contracted. In a May 2019 paper published in Nature Geoscience, Thomas Watters and his coauthors provide evidence that this fault and others like it are still active and producing moonquakes today. Video Credits: NASA/Goddard/SVS/Ernie Wright.

These fault scarps resemble small stair-step shaped cliffs when seen from the lunar surface, typically tens of yards (meters) high and extending for a few miles (several kilometers). Astronauts Eugene Cernan and Harrison Schmitt had to zig-zag their lunar rover up and over the cliff face of the Lee-Lincoln fault scarp during the Apollo 17 mission that landed in the Taurus-Littrow valley in 1972.

Image above: This is a view of the Taurus-Littrow valley taken by NASA’s Lunar Reconnaissance Orbiter spacecraft. The valley was explored in 1972 by the Apollo 17 mission astronauts Eugene Cernan and Harrison Schmitt. They had to zig-zag their lunar rover up and over the cliff face of the Lee-Lincoln fault scarp that cuts across this valley. Image Credits: NASA/GSFC/Arizona State University.

Watters is lead author of a study that analyzed data from four seismometers placed on the Moon by the Apollo astronauts using an algorithm, or mathematical program, developed to pinpoint quake locations detected by a sparse seismic network. The algorithm gave a better estimate of moonquake locations. Seismometers are instruments that measure the shaking produced by quakes, recording the arrival time and strength of various quake waves to get a location estimate, called an epicenter. The study was published May 13 in Nature Geoscience.

Astronauts placed the instruments on the lunar surface during the Apollo 11, 12, 14, 15, and 16 missions. The Apollo 11 seismometer operated only for three weeks, but the four remaining recorded 28 shallow moonquakes – the type expected to be produced by these faults – from 1969 to 1977. The quakes ranged from about 2 to around 5 on the Richter scale.

Using the revised location estimates from the new algorithm, the team found that eight of the 28 shallow quakes were within 30 kilometers (18.6 miles) of faults visible in lunar images. This is close enough to tentatively attribute the quakes to the faults, since modeling by the team shows that this is the distance over which strong shaking is expected to occur, given the size of these fault scarps. Additionally, the new analysis found that six of the eight quakes happened when the Moon was at or near its apogee, the farthest point from Earth in its orbit. This is where additional tidal stress from Earth’s gravity causes a peak in the total stress, making slip-events along these faults more likely.

Image above: This prominent lunar lobate thrust fault scarp is one of thousands discovered in Lunar Reconnaissance Orbiter Camera (LROC) images. The fault scarp or cliff is like a stair-step in the lunar landscape (left-pointing white arrows) formed when the near-surface crust is pushed together, breaks, and is thrust upward along a fault as the Moon contracts. Boulder fields, patches of relatively high bright soil or regolith, are found on the scarp face and back scarp terrain (high side of the scarp, right-pointing arrows). Image LROC NAC frame M190844037LR. Image Credits: NASA/GSFC/Arizona State University/Smithsonian.

“We think it’s very likely that these eight quakes were produced by faults slipping as stress built up when the lunar crust was compressed by global contraction and tidal forces, indicating that the Apollo seismometers recorded the shrinking Moon and the Moon is still tectonically active,” said Watters. The researchers ran 10,000 simulations to calculate the chance of a coincidence producing that many quakes near the faults at the time of greatest stress. They found it is less than 4 percent. Additionally, while other events, such as meteoroid impacts, can produce quakes, they produce a different seismic signature than quakes made by fault slip events.

Other evidence that these faults are active comes from highly detailed images of the Moon by NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft. The Lunar Reconnaissance Orbiter Camera (LROC) has imaged over 3,500 of the fault scarps. Some of these images show landslides or boulders at the bottom of relatively bright patches on the slopes of fault scarps or nearby terrain. Weathering from solar and space radiation gradually darkens material on the lunar surface, so brighter areas indicate regions that are freshly exposed to space, as expected if a recent moonquake sent material sliding down a cliff. Examples of fresh boulder fields are found on the slopes of a fault scarp in the Vitello cluster and examples of possible bright features are associated with faults that occur near craters Gemma Frisius C and Mouchez L. Other LROC fault images show tracks from boulder falls, which would be expected if the fault slipped and the resulting quake sent boulders rolling down the cliff slope. These tracks are evidence of a recent quake because they should be erased relatively quickly, in geologic time scales, by the constant rain of micrometeoroid impacts on the Moon. Boulder tracks near faults in Schrödinger basin have been attributed to recent boulder falls induced by seismic shaking.

Images above: The Taurus-Littrow valley is the location of the Apollo 17 landing site (asterisk). Cutting across the valley, just above the landing site, is the Lee-Lincoln fault scarp. Movement on the fault was the likely source of numerous moonquakes that triggered events in the valley. 1) Large landslides on of slopes of South Massif draped relatively bright rocks and dust (regolith) on and over the Lee-Lincoln scarp. 2) Boulders rolled down the slopes of North Massif leaving tracks or narrow troughs in the regolith on the slopes of North Massif. 3) Landslides on southeastern slopes of the Sculptured Hills. Images Credits: NASA/GSFC/Arizona State University/Smithsonian.

Additionally, one of the revised moonquake epicenters is just 13 kilometers (8 miles) from the Lee-Lincoln scarp traversed by the Apollo 17 astronauts. The astronauts also examined boulders and boulder tracks on the slope of North Massif near the landing site. A large landslide on South Massif that covered the southern segment of the Lee-Lincoln scarp is further evidence of possible moonquakes generated by fault slip events.

“It’s really remarkable to see how data from nearly 50 years ago and from the LRO mission has been combined to advance our understanding of the Moon while suggesting where future missions intent on studying the Moon’s interior processes should go,” said LRO Project Scientist John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Since LRO has been photographing the lunar surface since 2009, the team would like to compare pictures of specific fault regions from different times to see if there is any evidence of recent moonquake activity. Additionally, “Establishing a new network of seismometers on the lunar surface should be a priority for human exploration of the Moon, both to learn more about the Moon’s interior and to determine how much of a hazard moonquakes present,” said co-author Renee Weber, a planetary seismologist at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Lunar Reconnaissance Orbiter (LRO). Image Credit: NASA

The Moon isn’t the only world in our solar system experiencing some shrinkage with age. Mercury has enormous thrust faults — up to about 600 miles (1,000 kilometers) long and over a mile (3 kilometers) high — that are significantly larger relative to its size than those on the Moon, indicating it shrank much more than the Moon. Since rocky worlds expand when they heat up and contract as they cool, Mercury’s large faults reveal that is was likely hot enough to be completely molten after its formation. Scientists trying to reconstruct the Moon’s origin wonder whether the same happened to the Moon, or if instead it was only partially molten, perhaps with a magma ocean over a more slowly heating deep interior. The relatively small size of the Moon’s fault scarps is in line with the more subtle contraction expected from a partially molten scenario.

NASA will send the first woman, and next man, to the Moon by 2024. These American astronauts will take a human landing system from the Gateway in lunar orbit, and land on the lunar South Pole. The agency will establish sustainable missions by 2028, then we’ll take what we learn on the Moon, and go to Mars.

This research was funded by NASA’s LRO project, with additional support from the Natural Sciences and Engineering Research Council of Canada. LRO is managed by NASA Goddard for the Science Mission Directorate at NASA Headquarters in Washington. The LROC is managed at Arizona State University in Tempe.

Related links:

Nature Geoscience: https://www.nature.com/articles/s41561-019-0362-2

Apollo 17 mission: https://www.nasa.gov/mission_pages/apollo/missions/apollo17.html

Lunar Reconnaissance Orbiter (LRO): http://www.nasa.gov/mission_pages/LRO/main/index.html

Lunar Reconnaissance Orbiter Camera (LROC): https://www.lroc.asu.edu/

Goddard Space Flight Center (GSFC): https://www.nasa.gov/centers/goddard/home/index.html

Marshall Space Flight Center: https://www.nasa.gov/centers/marshall/home/index.html

Images (mentioned), Video, (mentioned), Text, Credits: NASA/Bill Steigerwald/GSFC/Nancy Jones.

Best regards, Orbiter.chArchive link

Robotics and Space Biology Today as Cosmonauts Look to Next Spacewalk

ISS — Expedition 59 Mission patch.

May 13, 2019

A pair of robotic arms from Canada and Japan continued swapping experiment hardware on the International Space Station over the weekend. Meanwhile, the Expedition 59 crew started the week exploring robotics and biology today while a pair of cosmonauts look to the next spacewalk.

The 57.7-foot-long Canadarm2 robotic arm started removing a pair of external investigations last week from the SpaceX Dragon’s unpressurized trunk. The remotely controlled Canadarm2 first grabbed the new Orbiting Carbon Observatory-3 (OCO-3) then handed it off to the Japan Aerospace Exploration Agency’s (JAXA) robotic arm for installation on the Kibo lab module’s external pallet.

Image above: NASA astronaut Anne McClain works inside the Japanese Kibo laboratory module checking out the new Astrobee hardware. The cube-shaped, free-flying robotic assistant could save the crew time performing routine maintenance duties and providing additional lab monitoring capabilities. Image Credit: NASA.

The Canadarm2 next removed the Space Test Program-Houston 6 (STP-H6) experiment from Dragon and installed it on the station’s truss structure. STP-H6 provides a platform for studying space physics to improve spacecraft navigation and communication techniques. The Canadian robotic arm then removed the completed SCAN radio communications study from the truss and placed it inside Dragon’s trunk.

JAXA’s robotic arm also retrieved the Cloud-Aerosol Transport System (CATS) experiment from the station and handed it off to the Canadarm2 for installation inside Dragon’s trunk. CATS successfully began demonstrating atmospheric monitoring after its delivery aboard a SpaceX Dragon cargo craft in January 2015. CATS and SCAN will now burn up in the atmosphere when Dragon’s trunk separates from the resupply ship before it returns to Earth at the end of May.

Waxing Crescent Moon Above Earth’s Limb

Image above: The International Space Station crew photographed the waxing crescent moon just above Earth’s limb and the bluish hue of the atmosphere at the beginning of an orbital sunrise. A portion of one of the Space Station’s solar arrays is seen in the left foreground as the orbital complex flew 256 miles above the Sea of Japan. Image Credit: NASA.

Back inside the orbital lab today, NASA astronaut Anne McClain calibrated the Astrobee and mapped the Kibo lab module with the free-flying robotic assistant. Flight Engineers Nick Hague and Christina Koch continued exploring how space changes the immune system, pathogens and kidney cells.

Two cosmonauts, Commander Oleg Kononenko and Flight Engineer Alexey Ovchinin, are planning for the fourth spacewalk at the station this year on May 29. The duo is timelined for about six hours of experiment retrieval work, window cleaning and sample collecting on the station’s Russian segment.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Canadarm2 robotic arm: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

Orbiting Carbon Observatory-3 (OCO-3): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1786

Kibo lab module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Space Test Program-Houston 6 (STP-H6): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/search.html?#q=%22stp-h6%22&i=&p=&c=&g=&s=

SCAN: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=156

Cloud-Aerosol Transport System (CATS): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1007

Immune system: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7868

Pathogens: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7642

Kidney cells: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7819

Fourth spacewalk: https://www.nasa.gov/mission_pages/station/spacewalks/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.chArchive link

Huge growth in use of quartz for tools shows sophistication of ancient communities

A growth in the use of crystal quartz to make tools thousands of years ago shows the sophistication of ancient communities, according to new research.

Huge growth in use of quartz for tools shows sophistication of ancient communities
Image shows the piezoelectric properties of a piece of quartz and its ability to generate an electric charge,
 as a toolmaker hits it [Credit: Exeter University]

The mineral was chosen because of its powerful symbolism, even though it involved painstaking work and other materials that would have been easier to use were available to prehistoric toolmakers, archaeologists argue.

Archaeologists have found there was a sudden spike in the number of tiny hand-made tools of less than 1cm made of crystal quartz in southern Africa around 14,000 years ago.

People could have used chert, which was more durable and found locally, but they may have chosen crystal quartz because it has several unique properties including as a source of light when it is struck and as a source of sharp cutting edges. Communities may have engaged with crystal quartz because they saw material as “alive” and believed they were able to harness the power from the mineral to see into the future.

The technique of constructing tiny crystal quartz tools would have taken specific sets of skills to master. Crystal quartz was also used in other parts of the world for tools at this time, when other raw materials were available. Crystal quartz is brittle and can fracture, but can give an exceptionally sharp and precise cutting edge.

Archaeologists examined two sites, in Sehonghong and Ntloana Tšoana, in Lesotho which are approximately 100 km apart from each other and in very different environments. Although communities used other raw materials for tool production, after around 14,000 years ago they both increasingly started to use crystal quartz. In some layers excavated more than 75 per cent of tools were made of the mineral, particularly those which hold remains from 18 thousand years ago at Sehonghong. This suggests that widely dispersed hunter-gatherer groups were connected and engaged with one another.

“We show that although crystal quartz was never the dominant raw material for tool production at either Sehonghong or Ntloana Tsoana, the mineral does show increased frequencies after 14,000 years ago,” says first author Justin Pargeter, from Emory University. “This pattern is shared between the two sites, separated by 100 kilometers and in very different environments, which suggests that widely dispersed hunter-gatherer groups were connected and engaged with one another.”

Dr Jamie Hampson, from the University of Exeter, who is co-author of the paper, said: “Quartz is abundant in the region, but from a functional point of view it is not the best material for making small tools. It takes more energy and time to use this material. If it flakes well, it can provide an extremely sharp cutting tool. But most of the time it just shatters.

“We found stone tools became smaller and smaller, there was a spike in their use, and increasingly they were made of crystal quartz instead of chert, which would have been a more readily available rock. We can’t say for sure why crystal quartz was used, but it may have been chosen for its unique symbolic qualities. This shows communities were more sophisticated and thoughtful than they were previously given credit for.”

Evidence from ethnographic texts and also from rock paintings suggests ancient communities at the time – in this region and elsewhere around the world — entered a hallucinogenic state. The luminescence caused by the sparks when crystal quartz was hit may have been part of their rituals performed in order to enter an altered state of consciousness and access the spirit world.

Dr Hampson has been examining evidence from cave paintings and engravings for 20 years, showing how they depict and embody these rituals. In some places people put pieces of quartz into gaps and cracks in the rock faces, seen by many indigenous communities as the barrier between their world and the spiritual world.

The findings are published in Antiquity.

Source: University of Exeter [May 10, 2019]



Modern economic theory explains prehistoric Mediterranean societies

A Florida State University professor’s research suggests a theory by famed economist Thomas Piketty on present-day wealth inequality actually explains a lot about how smaller-scale societies in the prehistoric Mediterranean developed.

Modern economic theory explains prehistoric Mediterranean societies
Gold pendant from the Aegina treasure showing a Minoan nature god — the ‘Master of Animals’
[Credit: British Museum]

Piketty’s theory says that high-growth economic conditions can slow the rate of wealth inequality and low-growth can accelerate it. In a new study, FSU Assistant Professor of Anthropology Thomas Leppard argues that certain hierarchical Mediterranean societies from about 3500 B.C. to 1000 B.C. fall into this low-growth context described by Piketty.

«Even though they never achieved the size and scale of societies in richer environments throughout the Old World, the fact that these Mediterranean societies developed in zones that were not prime for agriculture provided opportunities for some individuals to amass great wealth and social status compared to other individuals,» Leppard said.

Because many of these societies were pre-monetary, wealth and growth rates can be approximated by agricultural production, particularly of large-scale, extensive farming of different grains.

«We know that agriculture was, to an extent, vital for the emergence of urban and ‘state’ societies,» Leppard said.

Leppard argues that in larger, urban societies located in Mesopotamia, or near the Nile and the Yellow rivers, exaggerated income inequality took longer to occur because they were high-growth environments. This growth held off rapidly emergent wealth inequality and associated institutional hierarchies for longer, allowing these societies to coalesce at larger scales before durable hierarchies and state-type institutions appeared.

Piketty’s theory, Leppard said, illustrates that very different conditions can drive similar social outcomes, and this challenges some current models in anthropological archaeology on how societal hierarchies developed.

«Ultimately, if very different processes can drive the appearance of societies that appear structurally similar, we’re going to have to start thinking about multiple pathways to societies that we like to think of in one category,» Leppard said.

Leppard’s research is published in the journal Current Anthropology.

Author: Kathleen Haughney | Source: Florida State University [May 10, 2019]



Scientists prove gold purifying process used in medieval West Africa works

Humble fragments of clay crucibles and coin molds flecked with gold excavated by a joint team of British and Malian archaeologists in 2005 led archaeologist Sam Nixon, in consultation with Thilo Rehren, a specialist on ancient materials and technologies, to theorize how West Africans used them to purify gold and cast unmarked coins during the 10th and 11th centuries in Tadmekka, Mali. The theory was supported by writings from that time—largely thought in recent times to be exaggerated—that praised Tadmekka’s pure gold «blank dinar» [coins].

Scientists prove gold purifying process used in medieval West Africa works
These coin mould fragments, excavated at the site of Tadmekka, Mali, are archaeological remnants of medieval gold
processing. Institut des sciences humaines, Mali [Credit: Clare Britt/The Block Museum of Art]

Now a team of Northwestern University materials scientists have experimentally replicated the medieval gold purification method outlined by Nixon and Rehren in a 2014 paper using the same material resources and found the process works incredibly well. The unusual method involves heating a mixture of gold, sand and glass to high temperatures and separating out the gold.

«We proved this innovative process of purifying gold works,» said Marc Walton, who led the analytical team. «These medieval Africans, at a confluence of trade routes in the Sahara, were sophisticated in their use of available materials. Their technique of percolating raw materials through molten glass had not been seen before. It is unique to the archaeological record.»

The team used sand from nearby Lake Michigan, gold dust and recycled glass to conduct a reduced version of the original process. The gold dust was melted and filtered through crushed glass to purify it. Copies of the original clay thumbprint moulds were then used to cast replica blank coins in bronze instead of gold, due to gold’s high cost.

Walton is co-director of the Center for Scientific Studies in the Arts, a collaboration between Northwestern and the Art Institute of Chicago. He and former postdoctoral fellow Gianluca Pastorelli conducted the replication experiments after Kathleen Bickford Berzock, the curator of the Caravans of Gold exhibition and associate director of curatorial affairs at Northwestern’s Block Museum of Art, put them in touch with Nixon about the excavation.

«It’s exciting to connect esteemed colleagues across fields and particularly gratifying to learn that this unique casting process is indeed possible,» Berzock said. «Experiments like these allow us to envision life in medieval Saharan Africa with new detail and depth.»

Two of the moulds used to produce gold coins in Tadmekka and three replica coins made of wax are included in Berzock’s groundbreaking exhibition, Caravans of Gold, Fragments in Time: Art, Culture and Exchange Across Medieval Saharan Africa, currently at The Block Museum through July 21. The show on the movement of things, people and ideas across the Sahara Desert in the medieval period aims to change public perception of Africa’s role in the global economy in the 8th to 16th centuries.

«Archaeologists are bound by what they find,» said Walton, a research professor of materials science and engineering at Northwestern’s McCormick School of Engineering. «These fragments speak loudly about ancient civilizations and human history. Now we have proved the process used to refine gold in Tadmekka is real.»

Walton, Pastorelli and Nixon, curator of Africa in the department of Africa, Oceania and the Americas at the British Museum, are authors of a chapter in the exhibition catalog about the preliminary results from the gold processing replication.

Author: Megan Fellman | Source: Northwestern University [May 10, 2019]



Metal detectorists find largest Roman coin hoard in Britain

The largest haul of Roman coins from the early 4th Century AD ever found in Britain was discovered in Lincolnshire. It has now been declared as Roman treasure.

Metal detectorists find largest Roman coin hoard in Britain
The coins were found in a ceramic pot which was buried in the centre of a large oval pit
[Credit: Lincolnshire County Council]

Two metal detector enthusiasts – Rob Jones and Craig Paul – made the discovery near the village of Rauceby in Lincolnshire in July 2017 after having searched the area for years.
On Thursday, May 9, 2019 the coins were officially declared a treasure under the Treasure Act 1996 at Lincoln Coroner’s Court.

Rob, a 59-year-old engineering teacher from Lincoln, and his friend Craig, 32, a planner from Woodhall Spa, made the discovery. The hoard included over three thousand copper alloy coins which are now being looked at by The British Museum.

Metal detectorists find largest Roman coin hoard in Britain
The hoard consisted of more than three thousand copper alloy coins
[Credit: Lincolnshire County Council]

Rob said: “Our metal detectors started making signal noises, prompting us to dig down and have a look. I couldn’t believe what I was seeing. I’ve found a few things before, but absolutely nothing on this scale. I was totally amazed. Finding the coins was the ultimate experience that we will never forget. It’s an incredibly humbling experience knowing that when you discover something like this, the last time someone touched it was nearly 2,000 year ago! I was completely flabbergasted!”
A full investigation of the site was the undertaken by Craig, archaeologist at Lincolnshire County Council Dr Adam Daubney and Sam Bromage from the University of Sheffield. During the excavation another hoard of 10 coins was found.

Dr Daubney said the coins were found in a ceramic pot which was buried in the centre of a large oval pit lined with quarried limestone.

Metal detectorists find largest Roman coin hoard in Britain
The coins may have been buried as part of a «ceremonial or votive offering»
[Credit: Lincolnshire County Council]

He said: “What we found during the excavation suggests to me that the hoard was not put in the ground in secret, but rather was perhaps a ceremonial or votive offering. The Rauceby hoard is giving us further evidence for so-called ‘ritual’ hoarding in Roman Britain.”

Curator of Iron Age and Roman Coins Hoards at the British Museum, Dr Eleanor Grey, added: “At the time of the burial of the hoard around AD 307, the Roman Empire was increasingly decentralised and Britain was once again in the spotlight following the death of the emperor Constantius in York. Roman coins had begun to be minted in London for the first time. As the largest fully recorded find of this date from Britain, it has great importance for the study of this coinage and the archaeology of Lincolnshire.”

Author: Joseph Verney | Source: Lincolnshire Reporter [May 10, 2019]



French village offers reward to decipher mysterious stone inscription

Lapped by the waves of the Atlantic and visible at only low tide, a mysterious rock inscription believed to be centuries old and so far undeciphered lurks outside a French village in Brittany.

French village offers reward to decipher mysterious stone inscription
The mysterious inscription composed of indecipherable words on a rock in the
Brittany village of Plougastel-Daoulas 
[Credit: Fred Tanneau/AFP]

The town hall in Plougastel-Daoulas in the Finistere region of Brittany in northwest France is now offering a 2,000-euro ($2,250) reward for anyone who can decrypt the sequence of letters and symbol.

Could the small boulder have been used for a love letter whose secret has remained untouched for centuries, or a proud note left by an eighteenth-century fort-builder? Or something even more mysterious?

Locally, the rock is sometimes compared to the Rosetta Stone, the great ancient Egyptian stele now in the British Museum whose inscription was partly deciphered by the French Egyptologist Jean-Francois Champollion.

The authorities in Plougastel-Daoulas hope that their competition will shed light on the enigmatic piece of history.

«This inscription is a mystery and it is for this that we are launching the appeal,» said Veronique Martin, who is spearheading the search for a code-cracker.

The rock, which is around the size of a person, is accessed via a path from the hamlet of Illien ar Gwenn just to the north of Corbeau point.

French village offers reward to decipher mysterious stone inscription
French local councillor in charge of small heritage Michel Paugam shows the mysterious inscription
[Credit: Fred Tanneau/AFP]

The inscription fills the entirety of one of its sides and is mainly in capital letters but there are also pictures including a sailing boat. There are two dates, 1786 and 1787.

«These dates correspond more or less to the years that various artillery batteries that protected Brest and notably Corbeau Fort which is right next to it,» she said.

On a first glance the inscription defies interpretation.


«There are people who tell us that it’s Basque and others who say it’s old Breton,» said the mayor of Plougastel-Daoulas Dominique Cap.

«But we still have not managed to decipher the text,» the mayor told AFP, adding the rock was first spotted around three-four years ago.

French village offers reward to decipher mysterious stone inscription
Inscription detail [Credit: Fred Tanneau/AFP]

The appeal to crack the code has been made to linguists, historians, academics, students or simply people who enjoy code-breaking as a hobby.

A jury will then meet to choose the most plausible suggestion and award the prize.

«There are a lot of words, they’re letters from our alphabet, but we can’t read them, we can’t make them out,» said the municipal councillor in charge of local heritage Michel Paugam.

Source: AFP [May 11, 2019]



Peru to limit Machu Picchu access to prevent deterioration

Peru announced on Friday a two-week restriction to three important areas at Machu Picchu to prevent greater degradation to the iconic Inca citadel.

Peru to limit Machu Picchu access to prevent deterioration
Machu Picchu, which means «old mountain» in the Quechua language indigenous to the area, is at the top of a lush
mountain and was built during the reign of the Inca emperor Pachacuti (1438-1471) [Credit: AFP]

From May 15-28, access to the Temple of the Sun, Temple of the Condor and Intihuatana Stone will be strictly controlled at the UNESCO World Heritage Site, the government said.

«These measures are necessary to conserve Machu Picchu, given the evidence of deterioration» on stone surfaces caused by visitors to the three areas, the culture ministry said.

Almost 6,000 visitors a day are permitted onto the 15th century site in two waves. The new plan will give tourists just three hours to visit the three emblematic areas.

Authorities will evaluate the impact of the measures before applying new permanent rules from June 1.

Machu Picchu, which means «old mountain» in the Quechua language indigenous to the area, is at the top of a lush mountain and was built during the reign of the Inca emperor Pachacuti (1438-1471).

It lies around 100 kilometers (60 miles) from the Andean city of Cusco, the old Inca capital in southeastern Peru.

It was rediscovered in 1911 by the American explorer Hiram Bingham. UNESCO declared it a World Heritage Site in 1983.

Source: AFP [May 11, 2019]



How Venus and Mars can teach us about Earth

ESA — European Space Agency patch.

13 May 2019

One has a thick poisonous atmosphere, one has hardly any atmosphere at all, and one is just right for life to flourish – but it wasn’t always that way. The atmospheres of our two neighbours Venus and Mars can teach us a lot about the past and future scenarios for our own planet.

Rewind 4.6 billion years from the present day to the planetary construction yard, and we see that all the planets share a common history: they were all born from the same swirling cloud of gas and dust, with the newborn Sun ignited at the centre. Slowly but surely, with the help of gravity, dust accumulated into boulders, eventually snowballing into planet-sized entities.

The Moon, Mars and Venus rising over Earth’s horizon

Rocky material could withstand the heat closest to the Sun, while gassy, icy material could only survive further away, giving rise to the innermost terrestrial planets and the outermost gas and ice giants, respectively. The leftovers made asteroids and comets.

The atmospheres of the rocky planets were formed as part of the very energetic building process, mostly by outgassing as they cooled down, with some small contributions from volcanic eruptions and minor delivery of water, gases and other ingredients by comets and asteroids. Over time the atmospheres underwent a strong evolution thanks to an intricate combination of factors that ultimately led to the current status, with Earth being the only known planet to support life, and the only one with liquid water on its surface today.

We know from space missions such as ESA’s Venus Express, which observed Venus from orbit between 2006 and 2014, and Mars Express, investigating the Red Planet since 2003, that liquid water once flowed on our sister planets, too. While the water on Venus has long since boiled away, on Mars it is either buried underground or locked up in ice caps. Intimately linked to the story of water – and ultimately to the big question of whether life could have arisen beyond Earth – is the state of a planet’s atmosphere. And connected to that, the interplay and exchange of material between the atmosphere, oceans and the planet’s rocky interior.

A comparison of terrestrial planets

Planetary recycling

Back at our newly formed planets, from a ball of molten rock with a mantle surrounding a dense core, they stated to cool down. Earth, Venus and Mars all experienced outgassing activity in these early days, which formed the first young, hot and dense atmospheres. As these atmospheres also cooled, the first oceans rained down from the skies.

At some stage, though, the characteristics of the geological activity of the three planets diverged. Earth’s solid lid cracked into plates, in some places diving below another plate in subduction zones, and in other places colliding to create vast mountain ranges or pulling apart to create giant rifts or new crust. Earth’s tectonic plates are still moving today, giving rise to volcanic eruptions or earthquakes at their boundaries.

Venus, which is only slightly smaller than Earth, may still have volcanic activity today, and its surface seems to have been resurfaced with lavas as recently as half a billion years ago. Today it has no discernable plate tectonics system; its volcanoes were likely powered by thermal plumes rising through the mantle – created in a process that can be likened to a ‘lava lamp’ but on a gigantic scale.

Mars from horizon to horizon

Mars, being a lot smaller, cooled off more quickly than Earth and Venus, and when its volcanoes became extinct it lost a key means of replenishing its atmosphere. But it still boasts the largest volcano in the entire Solar System, the 25 kilometre high Olympus Mons, likely too the result of continuous vertical building of the crust from plumes rising from below. Even though there is evidence for tectonic activity within the last 10 million years, and even the occasional marsquake in present times, the planet is not believed to have an Earth-like tectonics system either.

It is not just global plate tectonics alone that make Earth special, but the unique combination with oceans. Today our oceans, which cover about two-thirds of Earth’s surface, absorb and store much of our planet’s heat, transporting it along currents around the globe. As a tectonic plate is dragged down into the mantle, it warms up and releases water and gases trapped in the rocks, which in turn percolate through hydrothermal vents on the ocean floor.

Extremely hardy lifeforms have been found in such environments at the bottom of Earth’s oceans, providing clues as to how early life may have begun, and giving scientists pointers on where to look elsewhere in the Solar System: Jupiter’s moon Europa, or Saturn’s icy moon Enceladus for example, which conceal oceans of liquid water beneath their icy crusts, with evidence from space missions like Cassini suggesting hydrothermal activity may be present.

Moreover, plate tectonics helps to modulate our atmosphere, regulating the amount of carbon dioxide on our planet over long timescales. When atmospheric carbon dioxide combines with water, carbonic acid is formed, which in turn dissolves rocks. Rain brings the carbonic acid and calcium to the oceans – carbon dioxide is also dissolved directly in oceans – where it is cycled back into the ocean floor. For almost half of Earth’s history the atmosphere contained very little oxygen. Oceanic cynobacteria were the first to use the Sun’s energy to convert carbon dioxide into oxygen, a turning point in providing the atmosphere that much further down the line allowed complex life to flourish. Without the planetary recycling and regulation between the mantle, oceans and atmosphere, Earth may have ended up more like Venus.

Extreme greenhouse effect

Venus is sometimes referred to as Earth’s evil twin on account of it being almost the same size but plagued with a thick noxious atmosphere and a sweltering 470ºC surface. Its high pressure and temperature is hot enough to melt lead – and destroy the spacecraft that dare to land on it. Thanks to its dense atmosphere, it is even hotter than planet Mercury, which orbits closer to the Sun. Its dramatic deviation from an Earth-like environment is often used as an example of what happens in a runaway greenhouse effect.

The main source of heat in the Solar System is the Sun’s energy, which warms a planet’s surface up, and then the planet radiates energy back into space. An atmosphere traps some of the outgoing energy, retaining heat – the so-called greenhouse effect. It is a natural phenomenon that helps regulate a planet’s temperature. If it weren’t for greenhouse gases like water vapour, carbon dioxide, methane and ozone, Earth’s surface temperature would be about 30 degrees cooler than its present +15ºC average.

Earth’s evil twin

Over the past centuries, humans have altered this natural balance on Earth, strengthening the greenhouse effect since the dawn of industrial activity by contributing additional carbon dioxide along with nitrogen oxides, sulphates and other trace gases and dust and smoke particles into the air. The long-term effects on our planet include global warming, acid rain and the depletion of the ozone layer. The consequences of a warming climate are far-reaching, potentially affecting freshwater resources, global food production and sea level, and triggering an increase in extreme-weather events.

There is no human activity on Venus, but studying its atmosphere provides a natural laboratory to better understand a runaway greenhouse effect. At some point in its history, Venus began trapping too much heat. It was once thought to host oceans like Earth, but the added heat turned water into steam, and in turn, additional water vapour in the atmosphere trapped more and more heat until entire oceans completely evaporated. Venus Express even showed that water vapour is still escaping from Venus’ atmosphere and into space today.

Venus Express also discovered a mysterious layer of high-altitude sulphur dioxide in the planet’s atmosphere. Sulphur dioxide is expected from the emission of volcanoes – over the mission’s duration Venus Express recorded large changes in the sulphur dioxide content of the atmosphere. This leads to sulphuric acid clouds and droplets at altitudes of about 50-70 km – any remaining sulphur dioxide should be destroyed by intense solar radiation. So it was a surprise for Venus Express to discover a layer of the gas at around 100 km. It was determined that evaporating sulphuric acid droplets free gaseous sulphuric acid that is then broken apart by sunlight, releasing the sulphur dioxide gas.

The observation adds to the discussion what might happen if large quantities of sulphur dioxide are injected into Earth’s atmosphere – a proposal made for how to mitigate the effects of the changing climate on Earth. The concept was demonstrated from the 1991 volcanic eruption of Mount Pinatubo in the Philippines, when sulphur dioxide ejected from the eruption created small droplets of concentrated sulphuric acid – like those found in Venus’ clouds – at about 20 km altitude. This generated a haze layer and cooled our planet globally by about 0.5ºC for several years. Because this haze reflects heat it has been proposed that one way to reduce global temperatures would be to inject artificially large quantities of sulphur dioxide into our atmosphere. However, the natural effects of Mt Pinatubo only offered a temporary cooling effect. Studying the enormous layer of sulphuric acid cloud droplets at Venus offers a natural way to study the longer term effects; an initially protective haze at higher altitude would eventually be converted back into gaseous sulphuric acid, which is transparent and allows all the Sun’s rays through. Not to mention the side-effect of acid rain, which on Earth can cause harmful effects on soils, plant life and water.

Global freezing

Our other neighbour, Mars, lies at another extreme: although its atmosphere is also predominantly carbon dioxide, today it hardly has any at all, with a total atmospheric volume less than 1% of Earth’s.

Mars’ existing atmosphere is so thin that although carbon dioxide condenses into clouds, it cannot retain sufficient energy from the Sun to maintain surface water – it vaporises instantly at the surface. But with its low pressure and relatively balmy temperatures of -55ºC (ranging from -133ºC at the winter pole to +27ºC during summer), spacecraft don’t melt on its surface, allowing us greater access to uncover its secrets. Furthermore, thanks to the lack of recycling plate tectonics on the planet, four billion year old rocks are directly accessible to our landers and rovers exploring its surface. Meanwhile our orbiters, including Mars Express, which has been surveying the planet for more than 15 years, are constantly finding evidence for its once flowing waters, oceans and lakes, giving a tantalizing hope that it might have once supported life.

Terrestrial planet magnetospheres

The Red Planet too would have started out with a thicker atmosphere thanks to the delivery of volatiles from asteroids and comets, and volcanic outgassing from the planet as its rocky interior cooled down. It simply couldn’t hold on to its atmosphere most likely because of its smaller mass and lower gravity. In addition, its initial higher temperature would have given more energy to gas molecules in the atmosphere, allowing them to escape more easily. And, having also lost its global magnetic field early in its history, the remaining atmosphere was subsequently exposed to the solar wind – a continuous flow of charged particles from the Sun – that, just as on Venus, continues to strip away the atmosphere even today.

With a decreased atmosphere, the surface water moved underground, released as vast flash-floods only when impacts heated the ground and released the subsurface water and ice. It is also locked up in the polar ice caps. Mars Express also recently detected a pool of liquid water buried within two kilometres of the surface. Could evidence of life also be underground? This question is at the heart of Europe’s ExoMars rover, scheduled to launch in 2020 and land in 2021 to drill up to two metres below the surface to retrieve and analyse samples in search for biomarkers.

Mars is thought to be currently coming out of an ice age. Like Earth, Mars is sensitive to changes in factors such as the tilt of its rotational axis as it orbits the Sun; it is thought that the stability of water at the surface has varied over thousands to millions of years as the axial tilt of the planet and its distance from the Sun undergo cyclical changes. The ExoMars Trace Gas Orbiter, currently investigating the Red Planet from orbit, recently detected hydrated material in equatorial regions that could represent former locations of the planet’s poles in the past.

The Trace Gas Orbiter’s primary mission is to conduct a precise inventory of the planet’s atmosphere, in particular the trace gases which make up less than 1% of the planet’s total volume of atmosphere. Of particular interest is methane, which on Earth is produced largely by biological activity, and also by natural and geological processes. Hints of methane have previously been reported by Mars Express, and later by NASA’s Curiosity rover on the surface of the planet, but the Trace Gas Orbiter’s highly sensitive instruments have so far reported a general absence of the gas, deepening the mystery. In order to corroborate the different results, scientists are not only investigating how methane might be created, but also how it might be destroyed close to the surface. Not all lifeforms generate methane, however, and the rover with its underground drill will hopefully be able to tell us more. Certainly the continued exploration of the Red Planet will help us understand how and why Mars’ habitability potential has changed over time.

Dried out river valley network on Mars

Exploring farther

Despite starting with the same ingredients, Earth’s neighbours suffered devastating climate catastrophes and could not hold on to their water for long. Venus became too hot and Mars too cold; only Earth became the ‘Goldilocks’ planet with the just-right conditions. Did we come close to becoming Mars-like in a previous ice age? How close are we to the runaway greenhouse effect that plagues Venus? Understanding the evolution of these planets and the role of their atmospheres is tremendously important for understanding climatic changes on our own planet as ultimately the same laws of physics govern all. The data returned from our orbiting spacecraft provide natural reminders that climate stability is not something to be taken for granted.

In any case, in the very long term – billions of years into the future – a greenhouse Earth is an inevitable outcome at the hands of the aging Sun. Our once life-giving star will eventually swell and brighten, injecting enough heat into Earth’s delicate system to boil our oceans, sending it down the same pathway as its evil twin.

We are changing our natural world faster than at any other time in history. Understanding the intricacies of how Earth works as a system and the impact that human activity is having on natural processes are huge environmental challenges. Satellites are vital for taking the pulse of our planet, delivering the information we need to understand and monitor our precious world, and for making decisions to safeguard our future. Earth observation data is also key to a myriad of practical applications to improve everyday life and to boost economies. This week we focus on the world’s biggest conference on Earth observation where thousands of scientists and data users discuss the latest results and look to the future of Earth observation.

Related links:

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

ExoMars rover: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_2020_rover

Living Planet Symposium: http://www.esa.int/Our_Activities/Observing_the_Earth/Living_Planet_Symposium

Space Science: http://www.esa.int/Our_Activities/Space_Science

Images, Text, Credits: ESA/NASA/DLR/FU Berlin, CC BY-SA 3.0 IGO/MPS/DLR-PF/IDA.

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Creswell Crags Prehistoric Caves, Derbyshire 12.5.19. The location of some of...

Creswell Crags Prehistoric Caves, Derbyshire 12.5.19.

The location of some of Britain’s earliest cave art and occupied for over 100,000 years!

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Prehistoric Hyena Skull from Cresswell Crags, Worksop, Derbyshire, 12.5.19.

Prehistoric Hyena Skull from Cresswell Crags, Worksop, Derbyshire, 12.5.19.

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