Friday, June 22, 2018

Tongues of Dinosaurs More Like Alligators Than Lizards

Dinosaurs are often depicted as fierce creatures, baring their teeth, with tongues wildly stretching from their mouths like giant, deranged lizards. But new research reveals a major problem with this classic image: Dinosaurs couldn't stick out their tongues like lizards. Instead, their tongues were probably rooted to the bottoms of their mouths in a manner akin to alligators.

Researchers from The University of Texas at Austin and the Chinese Academy of Sciences made the discovery by comparing the hyoid bones -- the bones that support and ground the tongue -- of modern birds and crocodiles with those of their extinct dinosaur relatives. In addition to challenging depictions of dino tongues, the research proposes a connection on the origin of flight and an increase in tongue diversity and mobility.

Incredible fossils discovered in Northeast China with the hyoid bones preserved. The blue and green arrows are pointing to the hyoid apparatus.

Credit: Li et al. 2018

The research was published June 20 in the journal PLOS ONE.

"Tongues are often overlooked. But, they offer key insights into the lifestyles of extinct animals," said lead author Zhiheng Li, an associate professor at the Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences.He conducted the work while earning his Ph.D. at the UT Jackson School of Geosciences.

The researchers made their discovery by comparing the hyoid bones of extinct dinosaurs, pterosaurs and alligators to the hyoid bones and muscles of modern birds and alligator specimens. Hyoid bones act as anchors for the tongue in most animals, but in birds these bones can extend to the tip. Because extinct dinosaurs are related to crocodiles, pterosaurs and modern birds, comparing anatomy across these groups can help scientists understand the similarities and differences in tongue anatomy and how traits evolved through time and across different lineages.

Reconstructions of dinosaurs at museums and theme parks often show their tongues wildly waving--a feature that is incorrect, according to new research led by The University of Texas at Austin and the Chinese Academy of Sciences.

Credit:  Spencer Wright

The comparison process involved taking high-resolution images of hyoid muscles and bones from 15 modern specimens, including three alligators and 13 bird species as diverse as ostriches and ducks, at the Jackson School's High-Resolution X-Ray Computed Tomography Facility (UTCT). The fossil specimens, most from northeastern China, were scrutinized for preservation of the delicate tongue bones and included small bird-like dinosaurs, as well as pterosaurs and a Tyrannosaurus rex.

The results indicate that hyoid bones of most dinosaurs were like those of alligators and crocodiles -- short, simple and connected to a tongue that was not very mobile. Co-author and Jackson School Professor Julia Clarke said that these findings mean that dramatic reconstructions that show dinosaurs with tongues stretching out from between their jaws are wrong.

"They've been reconstructed the wrong way for a long time," Clarke said. "In most extinct dinosaurs their tongue bones are very short. And in crocodilians with similarly short hyoid bones, the tongue is totally fixed to the floor of the mouth."

Clarke is no stranger to overturning dinosaur conventions. Her 2016 study on dinosaur vocalizations found evidence that large dinosaurs might make booming or cooing sounds, similar to the sounds made by crocodiles and ostriches.

Tongue and hyoid reconstructions from living taxa.

Credit: Li et al. 2018

In contrast to the short hyoid bones of crocodiles, the researchers found that pterosaurs, bird-like dinosaurs, and living birds have a great diversity in hyoid bone shapes. They think the range of shapes could be related to flight ability, or in the case of flightless birds such as ostriches and emus, evolved from an ancestor that could fly. The researchers propose that taking to the skies could have led to new ways of feeding that could be tied to diversity and mobility in tongues.

"Birds, in general, elaborate their tongue structure in remarkable ways," Clarke said. "They are shocking."

That elaboration could be related to the loss of dexterity that accompanied the transformation of hands into wings, Li said.

"If you can't use a hand to manipulate prey, the tongue may become much more important to manipulate food," Li said. "That is one of the hypotheses that we put forward."

The scientists note one exception linking tongue diversity to flight. Ornithischian dinosaurs -- a group that includes triceratops, ankylosaurs and other plant-eating dinosaurs that chewed their food -- had hyoid bones that were highly complex and more mobile, though they were structurally different from those of flying dinosaurs and pterosaurs.

Further research on other anatomical changes that occurred with shifts in tongue function could help improve our knowledge of the evolution of birds, Clarke said, giving an example of how changes in the tongues of living birds are associated with changes in the position of the opening of the windpipe. These changes could in turn affect how birds breathe and vocalize.

However, the researchers note that the fossil record as yet can't pin down when these changes to the windpipe occurred.

"There is more work to be done," Li said.

The study was funded by the Chinese Academy of Sciences, The University of Texas at Austin, the Smithsonian Institution and the Gordon and Betty Moore Foundation.




Contacts and sources:
Monica Kortsha
The University of Texas at Austin
 

Last of Universe's Missing Ordinary Matter Found



Researchers at the University of Colorado Boulder have helped to find the last reservoir of ordinary matter hiding in the universe.

Ordinary matter, or "baryons," make up all physical objects in existence, from stars to the cores of black holes. But until now, astrophysicists had only been able to locate about two-thirds of the matter that theorists predict was created by the Big Bang.

In the new research, an international team pinned down the missing third, finding it in the space between galaxies. That lost matter exists as filaments of oxygen gas at temperatures of around 1 million degrees Celsius, said CU Boulder's Michael Shull, a co-author of the study.

A simulation of the cosmic web, or diffuse tendrils of gas connecting galaxies across the universe.

Credit: NASA, ESA, E. Hallman (CU Boulder)

The finding is a major step for astrophysics. "This is one of the key pillars of testing the Big Bang theory: figuring out the baryon census of hydrogen and helium and everything else in the periodic table," said Shull of the Department of Astrophysical and Planetary Sciences (APS).

The new study, which will appear June 20 in Nature, was led by Fabrizio Nicastro of the Italian Istituto Nazionale di Astrofisica (INAF)--Osservatorio Astronomico di Roma and the Harvard-Smithsonian Center for Astrophysics.

Researchers have a good idea of where to find most of the ordinary matter in the universe--not to be confused with dark matter, which scientists have yet to locate: About 10 percent sits in galaxies, and close to 60 percent is in the diffuse clouds of gas that lie between galaxies.

In 2012, Shull and his colleagues predicted that the missing 30 percent of baryons were likely in a web-like pattern in space called the warm-hot intergalactic medium (WHIM). Charles Danforth, a research associate in APS, contributed to those findings and is a co-author of the new study.

To search for missing atoms in that region between galaxies, the international team pointed a series of satellites at a quasar called 1ES 1553--a black hole at the center of a galaxy that is consuming and spitting out huge quantities of gas. "It's basically a really bright lighthouse out in space," Shull said.

Scientists can glean a lot of information by recording how the radiation from a quasar passes through space, a bit like a sailor seeing a lighthouse through fog. First, the researchers used the Cosmic Origins Spectrograph on the Hubble Space Telescope to get an idea of where they might find the missing baryons. Next, they homed in on those baryons using the European Space Agency's X-ray Multi-Mirror Mission (XMM-Newton) satellite.

The team found the signatures of a type of highly-ionized oxygen gas lying between the quasar and our solar system--and at a high enough density to, when extrapolated to the entire universe, account for the last 30 percent of ordinary matter.

"We found the missing baryons," Shull said.

He suspects that galaxies and quasars blew that gas out into deep space over billions of years. Shull added that the researchers will need to confirm their findings by pointing satellites at more bright quasars.




Contacts and sources:
Daniel Strain
University of Colorado Boulder

Citation: Observations of the missing baryons in the warm–hot intergalactic medium
http://dx.doi.org/10.1038/s41586-018-0204-1

Understanding the Himalayas Using Mars Technology

The Himalayan Range includes some of the youngest and most spectacular mountains on Earth, but the rugged landscape that lends it the striking beauty for which it is known can also keep scientists from fully understanding how these mountains formed. "We know more about the rocks on parts of Mars than we do about some of the areas in the Himalaya," said Dr. Alka Tripathy-Lang.

"Many researchers have done extraordinary geologic mapping in this rugged region, but the fact is that some places are just completely inaccessible because of topography, elevation, or geopolitical issues. The rocks in those areas are an important piece of the tectonic puzzle and are important for understanding the way the region evolved," said Dr. Wendy Bohon. "The tools we used, originally developed for mapping rocks on Mars, were a way to safely access information about the rocks in the Himalayas."

This is a temple in the Nubra Valley of Ladakh, India, which is in the study area. The picture illustrates the enormous size and scale of the mountains in this part of the Himalayas.

Credit: Wendy Bohon

Bohon and colleagues worked with researchers at the Mars Space Flight Facility at Arizona State University to use data from the Earth orbiting satellite Terra in the same way planetary geologists have been using data from the Mars orbiting satellite Odyssey.

The researchers relied on the fact that every mineral has a unique spectral "signature," where some parts of the thermal infrared spectrum are absorbed and some parts are reflected. Rocks are made of different combinations of minerals, so when all of these mineral signatures are combined, they reveal the rock type. To easily distinguish between different kinds of rocks the researchers translated these signals into red/green/blue imagery, which results in a distinguishable color for each rock type that can be used to map the distribution of rocks throughout the region.

Top: Map made using ASTER satellite data imagery. Bottom: one "stretch" - or one color combination - of the ASTER data that was used to make the map.
ASTER images
Credit:  GSA

To double-check that the colors they're mapping are truly the rock type predicted by the imagery, the researchers took hand samples from accessible locations in the study area to the laboratory and measured the spectral signatures of each rock using a thermal emission spectrometer. Then they compared these laboratory signatures to those collected from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) instrument on the Terra satellite. They matched. "There is some variation between the lab and ASTER spectral signatures due to different factors like weathering and the averaging area, but overall the match between them was surprisingly consistent," said Tripathy-Lang.

The map they created revealed some interesting geology. They were able to clearly see "suture zones" -- ancient seafloor pushed up and exposed during the collision between India and Eurasia -- as well as subtle differences in the granitic mountains that indicates different phases of formation. They were also able the see the intersection of two massive fault systems, the Karakoram and Longmu Co Faults. "These fault systems are hugely important to the story of the Himalayan-Tibetan collision, and determining the way that these systems have evolved and how they interact is critical for understanding this part of the Himalayan Mountains," said Bohon.





Contacts and sources:
Kea Giles
Geological Society of America

Citation: Structural relationship between the Karakoram and Longmu Co Fault systems, southwestern Tibetan Plateau, revealed by ASTER remote sensing 
Authors: Wendy Bohon, Kip V. Hodges, Alka Tripathy-Lang, J. Ramón Arrowsmith, and Christopher Edwards. Contact author: Wendy Bohon, Wendy.Bohon@iris.edu. Paper URL: https://pubs.geoscienceworld.org/gsa/geosphere/article/532684/structural-relationship-between-the-karakoram-and.

Today's Beer Breweries Have Origins from the Iron Age

The importance of beer in society is well documented in inscriptions and legal documents dating back to the fourth millennium BC from Mesopotamian cultures and ancient Egypt

Archaeologists at Lund University in Sweden have found carbonised germinated grains showing that malt was produced for beer brewing as early as the Iron Age in the Nordic region. The findings made in Uppåkra in southern Sweden indicate a large-scale production of beer, possibly for feasting and trade.

"We found carbonised malt in an area with low-temperature ovens located in a separate part of the settlement. The findings are from the 400-600s, making them one of the earliest evidence of beer brewing in Sweden", says Mikael Larsson, who specialises in archaeobotany, the archaeology of human-plant interactions.

Carbonated turkeys from 400-600 BC found in Uppåkra interpreted as malt. 
Carbonated turkeys from 400-600 BC found in Uppåkra talkade as malt.  Photographer: Mikael Larsson
Photographer: Mikael Larsson

Archaeologists have long known that beer was an important product in ancient societies in many parts of the world. Through legal documents and images, it has been found, for example, that beer was produced in Mesopotamia as early as 4 000 BCE. However, as written sources in the Nordic region are absent prior to the Middle Ages (before ca 1200 CE), knowledge of earlier beer production is dependent on botanical evidence.

"We often find cereal grains on archaeological sites, but very rarely from contexts that testify as to how they were processed. These germinated grains found around a low-temperature oven indicate that they were used to become malt for brewing beer", says Mikael Larsson.

Beer is made in two stages. The first is the malting process, followed by the actual brewing. The process of malting starts by wetting the grain with water, allowing the grain to germinate. During germination, enzymatic activities starts to convert both proteins and starches of the grain into fermentable sugars. Once enough sugar has been formed, the germinated grain is dried in an oven with hot air, arresting the germination process. This is what happened in the oven in Uppåkra.

Ancient low temperature oven dug out by the researchers
The low temperature oven that the research group dug out.
Credit: Mikael Larsson / Lund University

"Because the investigated oven and carbonised grain was situated in an area on the site with several similar ovens, but absent of remains to indicate a living quarter, it is likely that large-scale production of malt was allocated to a specific area on the settlement, intended for feasting and/or trading", explains Mikael Larsson.

Early traces of malt in connection with beer brewing have only been discovered in two other places in the Nordic region. One is in Denmark from 100 CE and one is in Eketorp on Öland from around 500 CE.

"From other archaeological sites in the Nordic region, traces of the bog-myrtle plant have been found, which indicates beer brewing. Back then, bog-myrtle was used to preserve and flavour beer. It wasn't until later during the Middle Ages that hops took over as beer flavouring", Mikael Larsson concludes.

Facts: Method

Two-litre soil samples are taken from various archaeological contexts - in houses, in pits, around hearths and ovens. The plant material found is usually preserved in a carbonised state. The soil is mixed with water and the carbon rises to the surface and is sieved through a fine mesh. The particles extracted are dried and studied under a microscope.

Facts: Uppåkra

Uppåkra is currently the largest Iron Age settlements in southern Scandinavia and served as a densely populated political and religious centre of power for more than 1 000 years, from 100s BCE to the 1 000s CE. The many findings made of imported luxury items such as jewellery and glass bowls, and from a developed production of crafts, indicate that the location was both rich and a significant trading centre.



Contacts and sources:
Mikael Larsson
Lund University

Citation: Botanical evidence of malt for beer production in fifth–seventh century Uppåkra, Sweden

New Questions about the Early Inhabitants of North America

Scientists have shown that at the Anzick site in Montana – the only known Clovis burial site – the skeletal remains of a young child and the antler and stone artifacts found there were buried at the same time, raising new questions about the early inhabitants of North America, says a Texas A&M University professor involved in the research.

Michael Waters, director of the Center for the Study of the First Americans and colleagues from the University of Oxford and Stafford Research of Colorado have had their work published in the current issue of PNAS (Proceedings of the National Academy of Sciences).

The burial mound at the Anzick site.
The burial mound at the Anzick site.
Credit: Texas A&M University

The main focus of the team's research centered on properly dating the Anzick site which is named after the family who own the land. The site was discovered in 1968 by construction workers, who found the human remains and stone tools which include Clovis spear points and antler tools. It is the only known Clovis burial site and is associated with Clovis stone and antler artifacts.

"One thing that has always been a problem has been the accurate dating of the human remains from the site," explains Waters.

"The human remains yielded a younger age that was not in agreement with the ages from the antler artifacts which dated older than the human remains. If the human remains and Clovis artifacts were contemporaneous, they should be the same age." To resolve the issue, the team used a process called Specific Amino Acid Radiocarbon Dating, which allows a specific amino acid, in this case hydroxyproline, to be isolated from the human bones.

"This amino acid could only have come from the human skeleton and could not be contaminated," Waters adds.

"The other previous ages suffered from some sort of contamination. With the new method, we got very accurate and secure ages for the human remains based on dating hydroxyproline. As a test, we also redated the antler artifacts using this technique."

The results prove that both the human remains and antler Clovis artifacts are of the same date.

"The human remains and Clovis artifacts can now be confidently shown to be the same age and date between 12,725 to 12,900 years ago," Waters notes. "This is right in the middle to the end of the Clovis time period which ranges from 13,000 to 12,700 years ago.

Artifacts from the Anzick site.
some of the artifacts from the Anzick site
Credit: Texas A&M University

"This is important because we have resolved the dating issues at the site. Some researchers had argued that the human remains were not Clovis and were younger than the Clovis artifacts, based on the earlier radiocarbon dates. We have shown that they are the same age and confirmed that the Anzick site represents a Clovis burial."

While not the earliest inhabitants of the Americas, Clovis is the first widespread prehistoric culture that first appeared 13,000 years ago. Clovis originated south of the large Ice Sheets that covered Canada at that time and are the direct descendants of the earliest people who arrived in the New World around 15,000 years ago. Clovis people fashioned their stone spear tips with grooved, or fluted, bases. They invented the "Clovis point,' a spear-shaped weapon made of stone that is found in Texas and other portions of the United States and northern Mexico, and these weapons were used to hunt animals

The researchers say the findings will also help geneticists in their estimates of the timing of the peopling of the Americas because the Anzick genome is critical to understanding early settlements and the origin of modern Native peoples.



Contacts and sources:
Keith Randall
Texas A&M University



Citation: Reassessing the chronology of the archaeological site of Anzick
Lorena Becerra-Valdivia, Michael R. Waters, Thomas W. Stafford Jr., Sarah L. Anzick, Daniel Comeskey, Thibaut Devièse, and Thomas Higham http://dx.doi.org/10.1073/pnas.1803624115

Microscopic Paramedics and Emergency Room for DNA Rescue and Repair

The cell has its own paramedic team and emergency room to aid and repair damaged DNA, a new USC study reveals.

The findings are timely, as scientists are delving into the potential of genome editing with the DNA-cutting enzyme CRISPR-Cas9 to treat diseases or to advance scientific knowledge about humans, plants, animals and other organisms, said Irene Chiolo, Gabilan Assistant Professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences.

USC researchers studied the mechanism responsible for repairing DNA. 
Actin Myosin illustration
Illustration/Yekaterina Kadyshevskaya

Genome editing has arrived before scientists have thoroughly studied the significance and impact of DNA damage and repair on aging and diseases such as cancer. Chiolo’s work has offered more details about those processes.

Tracking what happened

Using fluorescent markers, Chiolo and her team of USC Dornsife researchers tracked what happened when DNA was damaged in fruit fly cells and mouse cells. They saw how the cell launches an emergency response to repair broken DNA strands from heterochromatin, a type of tightly packed DNA. The study was published Wednesday in Nature.

“Heterochromatin is also referred to as the ‘dark matter of the genome’ because so little is known about it,” Chiolo said. “But DNA damage in heterochromatin is likely a major driving force for cancer formation.”

DNA repair: Don’t call it junk

Repeated DNA sequences have had the bad nickname “junk DNA” for about 20 years. Scientists decoding the genome called it junk because they were initially focused on understanding the functions of individual genes.

Since then, studies have shown that repeated DNA sequences are in fact essential for many nuclear activities, but their defective repair is also linked to aging and disease.

“Heterochromatin is mostly composed of repeated DNA sequences,” Chiolo said. “The low gene content is part of the reason why these sequences are less characterized.”

In fact, mutations that compromise heterochromatin repair result in massive chromosome rearrangements affecting the entire genome.

First responders take a walk

The scientists found that after the DNA strands are broken, the cell prompts a series of threads — nuclear actin filaments — to assemble and create a temporary highway to the edge of the nucleus. Then come the paramedics — proteins known as myosins.

“Myosins are conveyed as a walking molecule because they have two legs. One is attached and the other moves,” Chiolo said. “It’s like a molecular machine that walks along the filaments.”

The myosins pick up the injured DNA, walk along the filament road and then reach the emergency room, a pore at the periphery of the nucleus.
In the ‘emergency room’

Based on a prior study, researchers knew that there was an “emergency room” — the nuclear pore where the cell fixes its broken DNA strands. Now, they have discovered how the damaged DNA travels there, Chiolo said.

“What we think is happening is that the damage triggers a defense mechanism that quickly builds the road, the actin filament, while also turning on an ambulance, the myosin.”

The researchers plan further studies examining the repair of DNA in heterochromatin.

“I’m excited to see how the molecular mechanisms we uncovered work in humans, as well as in plants that have much larger heterochromatin,” said Christopher Caridi, a co-lead author for the study and a postdoctoral researcher in Chiolo’s lab at USC Dornsife. It will be fascinating, he said, to see how such a complex repair mechanism functions and evolves over time and what aspects of the mechanisms may be adapted for other functions.



Contacts and sources:
Emily Gersema
University of Southern California


Citation: Nuclear F-actin and myosins drive relocalization of heterochromatic breaks.
Christopher P. Caridi, Carla D’Agostino, Taehyun Ryu, Grzegorz Zapotoczny, Laetitia Delabaere, Xiao Li, Varandt Y. Khodaverdian, Nuno Amaral, Emily Lin, Alesandra R. Rau, Irene Chiolo. Nature, 2018; DOI: 10.1038/s41586-018-0242-8

Horses Understand Human Emotions, Even Those of Strangers

Scientists demonstrated for the first time that horses integrate human facial expressions and voice tones to perceive human emotion, regardless of whether the person is familiar or not.

Recent studies showed the herd-forming animal possesses high communication capabilities, and can read the emotions of their peers through facial expressions and contact calls, or whinnies. Horses have long been used as a working animal and also as a companion animal in sports and leisure, establishing close relationships with humans just like dogs do with people.

Dogs are known to relate human facial expressions and voices to perceive human emotions, but little has been known as to whether horses can do the same.

Credit: Ayaka Takimoto

In the present study to be published in Scientific Reports, Associate Professor Ayaka Takimoto of Hokkaido University, graduate student Kosuke Nakamura of The University of Tokyo, and former Professor Toshikazu Hasegawa of The University of Tokyo, used the expectancy violation method to investigate whether horses cross-modally perceive human emotion by integrating facial expression and voice tone. They also tested whether the familiarity between the horse and the person affected the horse’s perception.

The expectancy violation method has been used to study infant cognitive development. Horses were shown a picture of a happy facial expression or an angry facial expression on a screen, and they then heard a pre-recorded human voice ­– praising or scolding – from a speaker behind the screen. Horses received both the congruent condition, in which the emotional values of facial expression and voice tone were matched, and the incongruent condition, in which they were not.

Horses are shown an angry or happy facial expression on the screen followed by a praising or scolding tone of voice during the test. Horses responded differently in a congruent and incongruent condition.

Photo taken by Kosuke Nakamura.

Results of the experiment showed that horses responded to voices 1.6 to 2.0 times faster in the incongruent condition than in the congruent condition regardless of familiarity of the person. In addition, the horses looked to the speaker 1.4 times longer in the incongruent condition than in the congruent condition when the person was familiar. These results suggest that horses integrate human facial expressions and voice tones to perceive human emotions, therefore an expectancy violation occurred when horses heard a human voice whose emotional value was not congruent with the human facial expression.

“Our study could contribute to the understanding of how humans and companion animals send and receive emotional signals to deepen our relationships, which could help establish a better relationship that emphasizes the well-being of animals,” says Ayaka Takimoto of Hokkaido University.

Associate Professor Ayaka Takimoto of Hokkaido University.

Credit: Hokkaido University

This study was supported by a Grant-in-Aid for Young Scientists (B) (15K20946) and Grants-in-Aid for Scientific Research on Innovative Areas (No. 26118004, No. 30172894).



Contacts and sources:
Associate Professor Ayaka Takimoto
Graduate School of Letters
Hokkaido University


Naoki Namba (Media Officer)
Global Relations Office
Institute for International Collaboration
Hokkaido University

Citation:  Cross-modal perception of human emotion in domestic horses (Equus caballus), Nakamura K., et al.,Scientific Reports, June 21, 2018. DOI: 10.1038/s41598-018-26892-6

Putting Sensors on Gummy Bears: Why Eat High Tech Candy?

Have you ever eaten high tech candy?  You may soon being doing so

Microelectrodes can be used for direct measurement of electrical signals in the brain or heart. These applications require soft materials, however. With existing methods, attaching electrodes to such materials poses significant challenges. A team at the Technical University of Munich (TUM) has now succeeded in printing electrodes directly onto several soft substrates.

Researchers from TUM and Forschungszentrum Jülich have successfully teamed up to perform inkjet printing onto a gummy bear. This might initially sound like scientists at play - but it may in fact point the way forward to major changes in medical diagnostics. For one thing, it was not an image or logo that Prof. Bernhard Wolfrum's team deposited on the chewy candy, but rather a microelectrode array. These components, comprised of a large number of electrodes, can detect voltage changes resulting from activity in neurons or muscle cells, for example.

Researchers from the Technical University of Munich (TUM) have succeeded in printing microelectrode arrays directly onto several soft substrates. Soft materials are better suited for devices that directly measure electrical signals from organs like the brain or heart.

Credit: N. Adly / TUM

Second, gummy bears have a property that is important when using microelectrode arrays in living cells: they are soft. Microelectrode arrays have been around for a long time. In their original form, they consist of hard materials such as silicon. This results in several disadvantages when they come into contact with living cells. In the laboratory, their hardness affects the shape and organization of the cells, for example. And inside the body, the hard materials can trigger inflammation or the loss of organ functionalities.

Rapid prototyping with inkjet printers

When electrode arrays are placed on soft materials, these problems are avoided. This has sparked intensive research into these solutions. Until now, most initiatives have used traditional methods, which are time-consuming and require access to expensive specialized laboratories. "If you instead print the electrodes, you can produce a prototype relatively quickly and cheaply. The same applies if you need to rework it," says Bernhard Wolfrum, Professor of Neuroelectronics at TUM. "Rapid prototyping of this kind enables us to work in entirely new ways."

Wolfrum and his team work with a high-tech version of an inkjet printer. The electrodes themselves are printed with carbon-based ink. To prevent the sensors from picking up stray signals, a neutral protective layer is then added to the carbon paths.

Materials for various applications

The researchers tested the process on various substrates, including PDMS (polydimethylsiloxane) - a soft form of silicon - agarose - a substance commonly used in biology experiments - and finally various forms of gelatin, including a gummy bear that was first melted and then allowed to harden. Each of these materials has properties suitable for certain applications. For example, gelatin-coated implants can reduce unwanted reactions in living tissue.

Through experiments with cell cultures, the team was able to confirm that the sensors provide reliable measurements. With an average width of 30 micrometers, they also permit measurements on a single cell or just a few cells. This is difficult to achieve with established printing methods.

"The difficulty is in fine-tuning all of the components - both the technical set-up of the printer and the composition of the ink," says Nouran Adly, the first author of the study. "In the case of PDMS, for example, we had to use a pre-treatment we developed just to get the ink to adhere to the surface."

Wide range of potential applications

Printed microelectrode arrays on soft materials could be used in many different areas. They are suitable not only for rapid prototyping in research, but could also change the way patients are treated. "In the future, similar soft structures could be used to monitor nerve or heart functions in the body, for example, or even serve as a pacemaker," says Prof. Wolfrum. At present he is working with his team to print more complex three-dimensional microelectrode arrays. They are also studying printable sensors that react selectively to chemical substances, and not only to voltage fluctuations.

Prof. Wolfrum's lab is part of the Munich School of BioEngineering (MSB). This interdisciplinary TUM research center is Europe's most multi-disciplinary university institution focused on the interface between medicine, engineering and natural sciences.



Contacts and sources:
Prof. Dr. Bernhard Wolfrum
Professor of Neuroelectronics
Munich School of BioEngineering
Department of Electrical and Computer Engineering
Technical University of Munich (TUM) 

Munich School of BioEngineering: https://www.bioengineering.tum.de/
Neuroelectronics Group: http://www.nel.ei.tum.de/

Citation: N. Adly, S. Weidlich, S. Seyock, F. Brings, A.Yakushenko, A. Offenhäusser, B. Wolfrum. "Printed Microelectrode Arrays on Soft Materials: From PDMS to Hydrogels." Npj Flexible Electronics 2:1 (2018). DOI:10.1038/s41528-018-0027-z.
Weblink (open access): https://www.nature.com/articles/s41528-018-0027-z

Eating Too Much Salt Can Shorten Your Life Confirms New Study

Eating foods high in salt is known to contribute to high blood pressure, but does that linear relationship extend to increased risk of cardiovascular disease and death? 

Recent cohort studies have contested that relationship, but a new study published in the International Journal of Epidemiology by investigators from Brigham and Women's Hospital and their colleagues using multiple measurements confirms it. The study suggests that an inaccurate way of estimating sodium intake may help account for the paradoxical findings of others.

Sea salt  File:Fleur de sel1.jpg
Credit: Christian Mertes / Wikimedia Commons

"Sodium is notoriously hard to measure," said Nancy Cook, ScD, a biostatistician in the Department of Medicine at BWH. "Sodium is hidden - you often don't know how much of it you're eating, which makes it hard to estimate how much a person has consumed from a dietary questionnaire. Sodium excretions are the best measure, but there are many ways of collecting those. In our work, we used multiple measures to get a more accurate picture."

Sodium intake can be measured using a spot test to determine how much salt has been excreted in a person's urine sample. However, sodium levels in urine can fluctuate throughout the day so an accurate measure of a person's sodium intake on a given day requires a full 24-hour sample. In addition, sodium consumption may change from day to day, meaning that the best way to get a full picture of sodium intake is to take samples on multiple days.

While previous studies have used spot samples and the Kawasaki formula, the team assessed sodium intake in multiple ways, including estimates based on that formula as well as ones based on the gold-standard method, which uses the average of multiple, non-consecutive urine samples. They assessed results for participants in the Trials of Hypertension Prevention, which included nearly 3,000 individuals with pre-hypertension.

The gold-standard method showed a direct linear relationship between increased sodium intake and increased risk of death. The team found that the Kawasaki formula suggested a J-shaped curve, which would imply that both low levels and high levels of sodium consumption were associated with increased mortality.

"Our findings indicate that inaccurate measurement of sodium intake could be an important contributor to the paradoxical J-shaped findings reported in some cohort studies. Epidemiological studies should not associate health outcomes with unreliable estimates of sodium intake," the authors wrote.

Funding for this work was provided by the National Heart, Lung and Blood Institute (NHLBI) grant numbers HL37849, HL37852, HL37853, HL37854, HL37872, HL37884, HL37899, HL37904, HL37906, HL37907, HL37924, HL57915; and 14GRNT18440013 from the American Heart Association.




Contacts and sources:
Haley Bridger
Brigham and Women's Hospital





Citation: He, FJ et al. "Errors in estimating usual sodium intake by the Kawasaki formula alter its relationship with mortality: implications for public health" International Journal of Epidemiology http://dx.doi.org/10.1093/ije/dyy114

E-Dermis Brings Sense of Feeling to Robotic Prosthetic Hands

Amputees often experience the sensation of a "phantom limb"—a feeling that a missing body part is still there.

That sensory illusion is closer to becoming a reality thanks to a team of engineers at Johns Hopkins University that has created an electronic skin. When layered on top of prosthetic hands, this e-dermis brings back a real sense of touch through the fingertips.

"After many years, I felt my hand, as if a hollow shell got filled with life again," says the amputee who served as the team's principal volunteer. (The research protocol used in the study does not allow identification of the amputee volunteers.)

Made of fabric and rubber laced with sensors to mimic nerve endings, e-dermis recreates a sense of touch as well as pain by sensing stimuli and relaying the impulses back to the peripheral nerves.

"We've made a sensor that goes over the fingertips of a prosthetic hand and acts like your own skin would," says Luke Osborn, a graduate student in biomedical engineering. "It's inspired by what is happening in human biology, with receptors for both touch and pain.


 Luke Osborn interacts with a prosthetic hand sporting the e-dermis

 Credit: Larry Canner  /Homewood Photography

"This is interesting and new," Osborn adds, "because now we can have a prosthetic hand that is already on the market and fit it with an e-dermis that can tell the wearer whether he or she is picking up something that is round or whether it has sharp points."

The work, published online in the journal Science Robotics, shows it's possible to restore a range of natural, touch-based feelings to amputees who use prosthetic limbs. The ability to detect pain could be useful, for instance, not only in prosthetic hands but also in lower limb prostheses, alerting the user to potential damage to the device.

Human skin is made up of a complex network of receptors that relay a variety of sensations to the brain. This network provided a biological template for the research team, which includes members from the Johns Hopkins departments of Biomedical Engineering, Electrical and Computer Engineering, and Neurology, and from the Singapore Institute of Neurotechnology.


Credit: Johns Hopkins University

Bringing a more human touch to modern prosthetic designs is critical, especially when it comes to incorporating the ability to feel pain, Osborn says.

"Pain is, of course, unpleasant, but it's also an essential, protective sense of touch that is lacking in the prostheses that are currently available to amputees," he says. "Advances in prosthesis designs and control mechanisms can aid an amputee's ability to regain lost function, but they often lack meaningful, tactile feedback or perception."

That's where the e-dermis comes in, conveying information to the amputee by stimulating peripheral nerves in the arm, making the so-called phantom limb come to life. Inspired by human biology, the e-dermis enables its user to sense a continuous spectrum of tactile perceptions, from light touch to noxious or painful stimulus.

The e-dermis does this by electrically stimulating the amputee's nerves in a non-invasive way, through the skin, says the paper's senior author, Nitish Thakor, a professor of biomedical engineering and director of the Biomedical Instrumentation and Neuroengineering Laboratory at Johns Hopkins.

"For the first time, a prosthesis can provide a range of perceptions from fine touch to noxious to an amputee, making it more like a human hand," says Thakor, co-founder of Infinite Biomedical Technologies, the Baltimore-based company that provided the prosthetic hardware used in the study.


The team created a "neuromorphic model" mimicking the touch and pain receptors of the human nervous system, allowing the e-dermis to electronically encode sensations just as the receptors in the skin would. Tracking brain activity via electroencephalography, or EEG, the team determined that the test subject was able to perceive these sensations in his phantom hand.

The researchers then connected the e-dermis output to the volunteer by using a noninvasive method known as transcutaneous electrical nerve stimulation, or TENS. In a pain-detection task the team determined that the test subject and the prosthesis were able to experience a natural, reflexive reaction to both pain while touching a pointed object and non-pain when touching a round object.

The e-dermis is not sensitive to temperature—for this study, the team focused on detecting object curvature (for touch and shape perception) and sharpness (for pain perception). The e-dermis technology could be used to make robotic systems more human, and it could also be used to expand or extend to astronaut gloves and space suits, Osborn says.

The researchers plan to further develop the technology and work to better understand how to provide meaningful sensory information to amputees in the hopes of making the system ready for widespread patient use.

Johns Hopkins is a pioneer in the field of upper limb dexterous prosthesis. More than a decade ago, the university's Applied Physics Laboratory led the development of the advanced Modular Prosthetic Limb, which an amputee patient controls with the muscles and nerves that once controlled his or her real arm or hand.




Contacts and sources:
Amy Lunday
Johns Hopkins University


Citation: Prosthesis with neuromorphic multilayered e-dermis perceives touch and pain.
Luke E. Osborn, Andrei Dragomir, Joseph L. Betthauser, Christopher L. Hunt, Harrison H. Nguyen, Rahul R. Kaliki, Nitish V. Thakor. Science Robotics, 2018; 3 (19): eaat3818 DOI: 10.1126/scirobotics.aat3818

Something Big Is Happening Under the Antarctic Ice Sheet

An international team led by DTU Space at the Technical University of Denmark with Colorado State University has found that the bedrock below the remote West Antarctic Ice Sheet is rising much more rapidly than previously thought, in response to ongoing ice melt.

The study, “Observed rapid bedrock uplift in the Amundsen Sea Embayment promotes ice-sheet stability,” reveals new insights on the geology of the region and its interaction with the ice sheet and is published in the journal Science.

Researchers said the findings have important implications in understanding and predicting the stability of the ice sheet and Earth’s rising sea levels.

Antarctica, as seen using Google Earth, and a cut to show the interior of the earth, where the mantle (red and dark red) and the core (yellow) are visible. The Amundsen Sea Embayment is indicated by the red rectangle. On the right, a photo reveals one of the GPS sites in the study.

a Google Earth view of Antarctica and a photo of a research site in W. Antarctica
 Credit: VR. Barletta, DTU Space at the Technical University of Denmark/Google Earth/Terry Wilson, The Ohio State University

“We studied a surprising and important mechanism, glacial isostatic adjustment, that may slow the demise of the massive West Antarctic Ice Sheet by lifting up the bedrock and sediments beneath the ice sheet,” explained CSU Professor Rick Aster, a co-author of the study and head of the Geosciences department at the university.

Ice sheet’s bowl-like position makes it susceptible to collapse

Scientists have been concerned that this ice sheet is particularly precarious in the face of a warming climate and ocean currents, because it is grounded hundreds to thousands of feet below sea level — unlike the ice sheets of East Antarctica or Greenland — and its base slopes inland. This bowl-like topography makes it susceptible to runaway destabilization and even complete collapse over centuries or even thousands of years.

The entirety of West Antarctica contains enough ice that, if it were to melt, would contribute more than 10 feet of average global sea level rise. In addition, the ice sheet is so massive that it attracts an ocean bulge, due to gravity. If this mass of water is released, it would lead to an additional increase of three feet or more to average sea level in parts of the Northern Hemisphere.

The West Antarctic Ice Sheet is currently contributing approximately 25 percent of global melting land-based ice each year, and recent satellite-based studies have shown that this amount has increased in recent decades. This figure is equivalent to about 37 cubic miles or a cube of over three miles on each side.

Co-authors of the study based at The Ohio State University led the installation of sensitive GPS stations on rock outcrops around the remote region to measure the rise in response to thinning ice and to directly measure the uplift due to changes in the ice sheet. These measurements showed that the bedrock uplift rates were as high as 1.6 inches per year, one of the fastest rates ever recorded in glacial areas.

Professor Rick Aster is a co-author of a new study that analyzed the remote West Antarctic Ice Sheet, which is susceptible to collapse.
                                                    
Credit: CSUi

“This very rapid uplift may slow the runaway wasting and eventual collapse of the ice sheet,” said Aster. The uplift tends to stabilize the critical grounding line where the ice sheet loses contact with underlying bedrock or sediment and goes afloat, he explained. This grounding line then counteracts the process of the ice sheet collapsing.

‘A game changer’

Researchers also found in this study that the uplift is accelerating, and predicted that it will continue to do so into the next century.

“Our research indicates that recent and ongoing ice loss in the region has been underestimated by approximately 10 percent in past studies, because this bedrock uplift was inadequately accounted for in satellite measurements,” said Aster.

Lead author Valentina Barletta, a postdoctoral researcher at DTU SPACE, Technical University of Denmark, said that this uplift is occurring quite rapidly, when compared with other regions of the earth where glaciers are melting.

“Normally we would see this type of uplift happening slowly, over thousands of years after an ice age,” said Barletta. “What we found tells us that earth’s underlying viscous mantle is relatively fluid and moves quickly when the weight of the ice is taken off,” she added.

Terry Wilson, professor emeritus of Earth Sciences at The Ohio State University, said the findings suggest that the geological conditions beneath the ice are very different from what scientists had previously believed.

“The rate of uplift we found is unusual and very surprising,” she said. “It’s a game changer.”

Seismic scans uncover clues about the earth’s mantle

Aster, Barletta and the study co-authors have deployed a large network of sensitive seismographs across Antarctica to produce seismic tomographic images — analogous to a gigantic CAT scan — of the deep earth below Antarctica.

The work assisted in the interpretation and modeling of the GPS uplift data by delineating a vast region of the earth’s mantle, 40 to 400 miles below West Antarctica, that is relatively hot and fluid.

Previous and related studies conducted by the research team have also revealed that some hotter features below Antarctica extend still deeper, over 600 miles, into the earth.

“These warmer mantle features drive the previously enigmatic volcanic activity in West Antarctica, including Mount Erebus on Ross Island,” said Aster. “This geothermal heat at the base of the ice sheet helps to sustain subglacial lakes in some regions and lubricates the ice sheet as it slips towards the ocean,”he added.

Aster said while the research does provide room for a positive outcome, if future global warming is extreme, the entire West Antarctic Ice Sheet will still melt.

“To keep global sea levels from rising more than a few feet during this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere through international cooperation and innovation,” he said.

Co-authors of this study also include researchers from DTU Compute at the Technical University of Denmark (DTU Compute), University of Washington, University of Colorado-Boulder, TU Delft in the Netherlands, University of Texas, University of Memphis, Penn State University and Washington University in St. Louis.

The Department of Geosciences is part of the Warner College of Natural Resources.

Contacts and sources:
Colorado State University



Citation: Valentina R. Barletta, Michael Bevis, Benjamin E. Smith, Terry Wilson, Abel Brown, Andrea Bordoni, Michael Willis, Shfaqat Abbas Khan, Marc Rovira-Navarro, Ian Dalziel, Robert Smalley, Eric Kendrick, Stephanie Konfal, Dana J. Caccamise, Richard C. Aster, Andy Nyblade, Douglas A. Wiens. Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability. Science, 2018; 360 (6395): 1335 DOI: 10.1126/science.aao1447  

Thursday, June 21, 2018

Hubble Proves Einstein Right on Galactic scales



An international team of astronomers using the NASA/ESA Hubble Space Telescope and the European Southern Observatory’s Very Large Telescope has made the most precise test of general relativity yet outside our Milky Way. The nearby galaxy ESO 325-G004 acts as a strong gravitational lens, distorting light from a distant galaxy behind it to create an Einstein ring around its centre. By comparing the mass of ESO 325-G004 with the curvature of space around it, the astronomers found that gravity on these astronomical length-scales behaves as predicted by general relativity. This rules out some alternative theories of gravity.

 
Credit: ESO, ESA, Hubble, M. Kornmesser, J. Colosimo, ALMA, NRAO, NAOJ, L. Calçada and the Hubble Heiratage Team (STScl/AURA)


An image of the nearby galaxy ESO 325-G004, created using data collected by the NASA/ESA Hubble Space Telescope and the MUSE instrument on the ESO’ Very Large Telescope. MUSE measured the velocity of stars in ESO 325-G004 to produce the velocity dispersion map that is overlaid on top of the Hubble Space Telescope image. Knowledge of the velocities of the stars allowed the astronomers to infer the mass of ESO 325-G004. The inset shows the Einstein ring resulting from the distortion of light from a more distant source by intervening lens ESO 325-004, which becomes visible after subtraction of the foreground lens light.
Image of ESO 325-G004
Credit: ESO, ESA/Hubble, NASA

Using the NASA/ESA Hubble Space Telescope and European Southern Observatory’s Very Large Telescope (VLT), a team led by Thomas Collett (University of Portsmouth, UK), was able to perform the most precise test of general relativity outside the Milky Way to date.

The theory of general relativity predicts that objects deform spacetime, causing any light that passes by to be deflected and resulting in a phenomenon known as gravitational lensing. This effect is only noticeable for very massive objects. A few hundred strong gravitational lenses are known, but most are too distant to precisely measure their mass. However, the elliptical galaxy ESO 325-G004 is amongst the closest lenses at just 450 million light-years from Earth.

Einstein’s general theory of relativity predicts that objects deform spacetime, causing any light that passes by to be deflected. This effect is only noticeable for very massive objects. One result of this deformation of spacetime is that light from distant sources is deflected around a massive intervening object, such as a galaxy. ESO 325-G004 is the large haze of light in the centre of the screen which is deforming light from the background galaxies.

Credit: ESO/L. Calçada

This diagram shows how the effect of gravitational lensing around a normal galaxy focuses the light coming from a very distant star-forming galaxy merger to created a distorted, but brighter view.

The NASA/ESA Hubble Space Telescope and many other telescopes on the ground and in space have enlisted the help of a galaxy-sized magnifying glass to reveal otherwise invisible detail and obtain the best view yet of a collision that took place between two galaxies when the Universe was only half its current age. The image showing these combined observations can be seen in the inset.

These new studies of the galaxy H-ATLAS J142935.3-002836 have shown that this complex and distant object looks surprisingly like the well-known local galaxy collision, the Antennae Galaxies.
How gravitational lensing acts as a magnifying glass — diagram
Credit: ESA/ESO/M. Kornmesser


Using the MUSE instrument on the VLT the team calculated the mass of ESO 325-G004 by measuring the movement of stars within it. Using Hubble the scientists were able to observe an Einstein ring resulting from light from a distant galaxy being distorted by the intervening ESO 325-G004. Studying the ring allowed the astronomers to measure how light, and therefore spacetime, is being distorted by the huge mass of ESO 325-G004.

This infographic compares the two methods used to measure the mass of the galaxy ESO 325-G004. The first method used ESO’s Very Large Telescope to measure the velocities of stars in ESO 325-G004. The second method used the NASA/ESA Hubble Space Telescope to observe an Einstein ring caused by light from a background galaxy being bent and distorted by ESO 325-G004. By comparing these two methods of measuring the strength of the gravity of ESO 325-G004, it was determined that Einstein’s general theory of relativity works on extragalactic scales — something that had not been previously tested.
Two methods of measuring the mass of a galaxy
Credit: ESA/Hubble, ESO, NASA
Collett comments: “We know the mass of the foreground galaxy from MUSE and we measured the amount of gravitational lensing we see from Hubble. We then compared these two ways to measure the strength of gravity — and the result was just what general relativity predicts, with an uncertainty of only nine percent. This is the most precise test of general relativity outside the Milky Way to date. And this using just one galaxy!”

General relativity has been tested with exquisite accuracy on Solar System scales, and the motions of stars around the black hole at the centre of the Milky Way are under detailed study, but previously there had been no precise tests on larger astronomical scales. Testing the long range properties of gravity is vital to validate our current cosmological model.

This video pans across NASA/ESA Hubble Space Telescope observations of the elliptical galaxy ESO 325-G004 that lies about 450 million light-years away. The galaxy is part of a diverse collection of galaxies in the cluster Abell S0740.

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

These findings may have important implications for models of gravity alternative to general relativity. These alternative theories predict that the effects of gravity on the curvature of spacetime are “scale dependent”. This means that gravity should behave differently across astronomical length-scales from the way it behaves on the smaller scales of the Solar System. Collett and his team found that this is unlikely to be true unless these differences only occur on length scales larger than 6000 light-years.

“The Universe is an amazing place providing such lenses which we can use as our laboratories,” adds team member Bob Nichol (University of Portsmouth). “It is so satisfying to use the best telescopes in the world to challenge Einstein, only to find out how right he was.”

This image from the NASA/ESA Hubble Space Telescope shows the diverse collection of galaxies in the cluster Abell S0740 that is over 450 million light-years away in the direction of the constellation Centaurus. The giant elliptical ESO 325-G004 looms large at the cluster's centre. Hubble resolves thousands of globular star clusters orbiting ESO 325-G004. Globular clusters are compact groups of hundreds of thousands of stars that are gravitationally bound together. At the galaxy's distance they appear as pinpoints of light contained within the diffuse halo. This image was created by combining Hubble science observations taken in January 2005 with Hubble Heritage observations taken a year later to form a 3-colour composite. The filters that isolate blue, red and infrared light were used with the Advanced Camera for Surveys aboard Hubble.
Hubble illuminates cluster of diverse galaxies
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

This research was presented in a paper entitled “A precise extragalactic test of General Relativity” by Collett et al., to appear in the journal Science.

Thomas Collett discusses the methods behind his research into whether Einstein’s general theory of relativity is correct on extragalactic length scales. This research was published in the journal, Science, in June 2018
s
Credit: University of Portsmouth
The international team is comprised of: Thomas E. Collett (Institute of Cosmology and Gravitation, University of Portsmouth, UK), Lindsay J. Oldham (Institute of Astronomy, University of Cambridge, UK, and Harvard College, Harvard-Smithsonian Center for Astrophysics, USA), Russell Smith (Centre for Extragalactic Astronomy, University of Durham, UK), Matthew W. Auger (Institute of Astronomy, University of Cambridge, UK), Kyle B. Westfall (ICG, Portsmouth, UK, and University of California, Santa Cruz, USA), David Bacon (ICG, Portsmouth, UK), Robert C. Nichol (ICG, Portsmouth, UK), Karen L. Masters (ICG, Portsmouth, UK), Kazuya Koyama (ICG, Portsmouth, UK) and Remco van den Bosch (Max Planck Institute for Astronomy, Garching, Germany).
Links




Contacts and sources:
Thomas Collett
University of Portsmouth

Bob Nichol
University of Portsmouth

Mathias Jäger
ESA/Hubble, Public Information Officer

Science paper

Tuesday, June 19, 2018

Two Strange New Creatures Discovered from Dawn of Animal Life

Earth’s first complex animals were an eclectic bunch that lived in the shallow oceans between 580-540 million years ago.

The iconic Dickinsonia — large flat animals with a quilt-like appearance — were joined by tube-shaped organisms, frond-like creatures that looked more like plants, and several dozen other varieties already characterized by scientists.

Add to that list two new animals discovered by a University of California Riverside (UCR)-led team of researchers:
  • Obamus coronatus, a name that honors President Barack Obama’s passion for science. This disc-shaped creature was between 0.5-2 cm across with raised spiral grooves on its surface. Obamus coronatus did not seem to move around, rather it was embedded to the ocean mat, a thick layer of organic matter that covered the early ocean floor.
  • Attenborites janeae, named after the English naturalist and broadcaster Sir David Attenborough for his science advocacy and support of paleontology. This tiny ovoid, less than a centimeter across, was adorned with internal grooves and ridges giving it a raisin-like appearance.

Two new Ediacaran-era fossils discovered by UCR researchers: Obamus coronatus (left) and Attenborites janeae.
Photos of the two new fossils discovered by UCR researchers.
 Credit:  UCR

The discovery of Obamus coronatus was published online June 14 in the Australian Journal of Earth Sciences, or AJES, and the Attenborites janeae paper is forthcoming in the same journal. The studies were led by Mary Droser, a professor of paleontology in UCR’s Department of Earth Sciences. Both papers will be included in print in a 2019 thematic AJES issue focusing on South Australia’s Flinders Ranges region, where the discoveries were made.

Part of the Ediacara Biota, the soft-bodied animals are visible as fossils cast in fine-grained sandstone that have been preserved for hundreds of millions of years. These Precambrian lifeforms represent the dawn of animal life and are named after the Ediacara Hills in the Flinders Ranges, the first of several areas in the world where they have been found.

An extremely well-preserved example of the fossil animal Dickinsonia costata found in a bed that was recently excavated by UCR researchers.

Credit: UCR


In the hierarchical taxonomic classification system, the Ediacara Biota are not yet organized into families, and little is known about how they relate to modern animals. About 50 genera have been described, which often have only one species.

“The two genera that we identified are a new body plan, unlike anything else that has been described,” Droser said. “We have been seeing evidence for these animals for quite a long time, but it took us a while to verify that they are animals within their own rights and not part of another animal.”

The animals were glimpsed in a particularly well-preserved fossil bed described in another paper published by Droser’s group that will be included in the Flinders Ranges issue of AJES. The researchers dubbed this fossil bed “Alice’s Restaurant Bed,” a tribute to the Arlo Guthrie song and its lyric, “You can get anything you want at Alice’s Restaurant.”

“I’ve been working in this region for 30 years, and I’ve never seen such a beautifully preserved bed with so many high quality and rare specimens, including Obamus and Attenborites,” Droser said. “The AJES issue on the Flinders Ranges will support South Australia’s effort to obtain World Heritage Site status for this area, and this new bed demonstrates the importance of protecting it.”

The titles of the papers are:

Stuck in the mat: Obamus coronatus, a new benthic organism from the Ediacara Member, Rawnsley Quartzite, South Australia

You can get anything you want from Alice’s Restaurant Bed: exceptional preservation and an unusual fossil assemblage from a newly excavated bed (Ediacara Member, Nilpena, South Australia)

Attenborites janeae: A new enigmatic organism from the Ediacara Member (Rawnsley Quartzite), South Australia (forthcoming).

In addition to Droser, authors from UCR include Scott Evans, a graduate student in the Department of Earth Sciences; and Peter Dzaugis, a volunteer and field assistant. The work was performed in collaboration with James Gehling of the South Australian Museum in Adelaide, a co-author on the papers.

Ian Hughes of Scripps Institute of Oceanography at UC San Diego, and Emily Hughes of Wesleyan University also participated in the research.



Contacts and sources:
Sarah Nightingale
University of California Riverside

Citation: Stuck in the mat: Obamus coronatus, a new benthic organism from the Ediacara Member, Rawnsley Quartzite, South Australia

You can get anything you want from Alice’s Restaurant Bed: exceptional preservation and an unusual fossil assemblage from a newly excavated bed (Ediacara Member, Nilpena, South Australia)

Monday, June 18, 2018

Explosive Volcanoes Spawned Mysterious Martian Rock Formation

Explosive volcanic eruptions that shot jets of hot ash, rock and gas skyward are the likely source of a mysterious Martian rock formation, a new study finds. The new finding could add to scientists' understanding of Mars's interior and its past potential for habitability, according to the study's authors.

The Medusae Fossae Formation is a massive, unusual deposit of soft rock near Mars's equator, with undulating hills and abrupt mesas. Scientists first observed the Medusae Fossae with NASA's Mariner spacecraft in the 1960s but were perplexed as to how it formed.

Now, new research suggests the formation was deposited during explosive volcanic eruptions on the Red Planet more than 3 billion years ago. The formation is about one-fifth as large as the continental United States and 100 times more massive than the largest explosive volcanic deposit on Earth, making it the largest known explosive volcanic deposit in the solar system, according to the study's authors.

An isolated hill in the Medusae Fossae Formation. The effect of wind erosion on this hill is evident by its streamlined shape. 
HRSC_2.png
Credit: High Resolution Stereo Camera/European Space Agency.

"This is a massive deposit, not only on a Martian scale, but also in terms of the solar system, because we do not know of any other deposit that is like this," said Lujendra Ojha, a planetary scientist at Johns Hopkins University in Baltimore and lead author of the new study published in the Journal of Geophysical Research: Planets, a journal of the American Geophysical Union.

Formation of the Medusae Fossae would have marked a pivotal point in Mars's history, according to the study's authors. The eruptions that created the deposit could have spewed massive amounts of climate-altering gases into Mars's atmosphere and ejected enough water to cover Mars in a global ocean more than 9 centimeters (4 inches) thick, Ojha said.

A 13-kilometer (8-mile) diameter crater being infilled by the Medusae Fossae Formation. 
HRSC_3.png
Credit: High Resolution Stereo Camera/European Space Agency

Greenhouse gases exhaled during the eruptions that spawned the Medusae Fossae could have warmed Mars's surface enough for water to remain liquid at its surface, but toxic volcanic gases like hydrogen sulfide and sulfur dioxide would have altered the chemistry of Mars's surface and atmosphere. Both processes would have affected Mars's potential for habitability, Ojha said.

Determining the source of the rock

The Medusae Fossae Formation consists of hills and mounds of sedimentary rock straddling Mars's equator. Sedimentary rock forms when rock dust and debris accumulate on a planet's surface and cement over time.

Scientists have known about the Medusae Fossae for decades, but were unsure whether wind, water, ice or volcanic eruptions deposited rock debris in that location.

Previous radar measurements of Mars's surface suggested the Medusae Fossae had an unusual composition, but scientists were unable to determine whether it was made of highly porous rock or a mixture of rock and ice. In the new study, Ojha and a colleague used gravity data from various Mars orbiter spacecraft to measure the Medusae Fossae's density for the first time. They found the rock is unusually porous: it's about two-thirds as dense as the rest of the Martian crust. They also used radar and gravity data in combination to show the Medusae Fossae's density cannot be explained by the presence of ice, which is much less dense than rock.

A global geographic map of Mars, with the location of the Medusae Fossae Formation circled in red. 
Mars_geographical_map.jpg
Credit: MazzyBor, CC BY-SA 4.0 via Wikimedia Commons

Because the rock is so porous, it had to have been deposited by explosive volcanic eruptions, according to the researchers. Volcanoes erupt in part because gases like carbon dioxide and water vapor dissolved in magma force the molten rock to rise to the surface. Magma containing lots of gas explodes skyward, shooting jets of ash and rock into the atmosphere.

Ash from these explosions plummets to the ground and streams downhill. After enough time has passed, the ash cements into rock, and Ojha suspects this is what formed the Medusae Fossae. As much as half of the soft rock originally deposited during the eruptions has eroded away, leaving behind the hills and valleys seen in the Medusae Fossae today.

Understanding Mars's interior

The new findings suggest the Martian interior is more complex than scientists originally thought, according to Ojha. Scientists know Mars has some water and carbon dioxide in its crust that allow explosive volcanic eruptions to happen on its surface, but the planet's interior would have needed massive amounts of volatile gases - substances that become gas at low temperatures - to create a deposit of this size, he said.

"If you were to distribute the Medusae Fossae globally, it would make a 9.7-meter (32-foot) thick layer." Ojha said. "Given the sheer magnitude of this deposit, it really is incredible because it implies that the magma was not only rich in volatiles and also that it had to be volatile-rich for long periods of time."

This graphic shows the relative size of the Medusae Fossae Formation compared to Fish Canyon Tuff, the largest explosive volcanic deposit on Earth.
018_29552_Medusa-Fossae-Infographic.jpg
Credit: AGU
The new study shows the promise of gravity surveys in interpreting Mars's rock record, according to Kevin Lewis, a planetary scientist at Johns Hopkins University and co-author of the new study. "Future gravity surveys could help distinguish between ice, sediments and igneous rocks in the upper crust of the planet," Lewis said.
 


Contacts and sources:
Lauren Lipuma
The American Geophysical Union

Researchers Map Brain Of Blind Patient Who Can See Motion

 Neuroscientists at Western University’s Brain and Mind Institute, have confirmed and detailed a rare case of a blind woman able to see objects – but only if in motion.

A team led by neuropsychologist Jody Culham has conducted the most extensive analysis and brain mapping to date of a blind patient, to help understand the remarkable vision of a 48-year-old Scottish woman, Milena Canning.

Neuropsychologist Jody Culham of the Brain and Mind Institute at Western University in London, Canada, led research into the brain of a blind woman able to se the motion of objects but not the objects themselves.

Credit: Western University

Canning lost her sight 18 years ago after a respiratory infection and series of strokes. Months after emerging blind from an eight-week coma, she was surprised to see the glint of a sparkly gift bag, like a flash of green lightning.

Then she began to perceive, sporadically, other moving things: her daughter’s ponytail bobbing when she walked, but not her daughter’s face; rain dripping down a window, but nothing beyond the glass; and water swirling down a drain, but not a tub already full with water.

Glaswegian ophthalmologist Gordon Dutton referred Canning to the Brain and Mind Institute in London, Canada, where tests by Culham’s team included functional Magnetic Resonance Imaging (fMRI) to examine the real-time structure and workings of her brain.

They determined Canning has a rare phenomenon called Riddoch syndrome – in which a blind person can consciously see an object if moving but not if stationary.

“She is missing a piece of brain tissue about the size of an apple at the back of her brain – almost her entire occipital lobes, which process vision,” says Culham, a professor in the Department of Psychology and Graduate Program in Neuroscience.

“In Milena’s case, we think the ‘super-highway’ for the visual system reached a dead end. But rather than shutting down her whole visual system, she developed some ‘back roads’ that could bypass the superhighway to bring some vision – especially motion – to other parts of the brain.”

In essence, Canning’s brain is taking unexpected, unconventional detours around damaged pathways.

During the study, Canning was able to recognize the motion, direction, size and speed of balls rolled towards her; and to command her hand to open, intercept and grab them at exactly the right time. She could navigate around chairs.

Yet she inconsistently identified an object’s colour, and was able only half the time to detect whether someone’s hand in front of her showed thumb-up or thumb-down.

“This work may be the richest characterization ever conducted of a single patient’s visual system,” says Culham. “She has shown this very profound recovery of vision, based on her perception of motion.”

The research shows the remarkable plasticity of the human brain in finding work-arounds after catastrophic injuries. And it suggests conventional definitions of ‘sight’ and ‘blindness’ are fuzzier than previously believed.

“Patients like Milena give us a sense of what is possible and, even more importantly, they give us a sense of what visual and cognitive functions go together,” Culham says.

For Canning, the research at BMI helps explain more about what she perceives and how her brain is continuing to change.She is able to navigate around chairs, can see a bright-shirted soccer goalie and can see steam rising from her morning cup of coffee, for example.

“I can’t see like normal people see or like I used to see. The things I’m seeing are really strange. There is something happening and my brain is trying to rewire itself or trying different pathways,” Canning says.

The research is newly publishedin the journal Neuropsychologia.




Contacts and sources:
University of Western Ontario

Citation: Psychophysical and neuroimaging responses to moving stimuli in a patient with the Riddoch phenomenon due to bilateral visual cortex lesions.
Michael J. Arcaro, Lore Thaler, Derek J. Quinlan, Simona Monaco, Sarah Khan, Kenneth F. Valyear, Rainer Goebel, Gordon N. Dutton, Melvyn A. Goodale, Sabine Kastner, Jody C. Culham. Neuropsychologia, 2018; DOI: 10.1016/j.neuropsychologia.2018.05.008

True Origin of Ancient Turquoise Unveiled

The true source of turquoise used by ancient Mesoamerican people has been found and it is not what scientists thought.

New research published June 13th in the journal Science Advances overturns more than a century of thought about the source of turquoise used by ancient civilizations in Mesoamerica, the vast region that extends from Central Mexico to Central America. For more than 150 years, scholars have argued that the Aztec and Mixtec civilizations, which revered the precious, blue-green mineral, acquired it through import from the American Southwest. However, extensive geochemical analyses reveal that the true geologic source of Aztec and Mixtec turquoise lies within Mesoamerica.

This is a close up view of Mixteca-style mask decorated with turquoise mosaic from the collections of the Smithsonian Institution-National Museum of the American Indian. NMAI Catalog #10/8712.

Credit:  Alyson M. Thibodeau

Geochemist Alyson Thibodeau, assistant professor of earth sciences at Dickinson College, and a team of researchers from the University of Arizona, California State University at San Bernardino, and the Museo del Templo Mayor in Mexico City, measured the isotopic signatures of Mesoamerican turquoise artifacts associated with both the Aztecs and Mixtecs. These isotopic signatures function like fingerprints that can be used to determine the geologic origins of the turquoise.

Specifically, Thibodeau and her research team carried out analyses of lead and strontium isotopes on fragments of turquoise-encrusted mosaics, which are one of the most iconic forms of ancient Mesoamerican art. Their samples include dozens of turquoise mosaic tiles excavated from offerings within the Templo Mayor, the ceremonial and ritual center of the Aztec empire, and which is located in present-day Mexico City.

This is a close up view of Mixteca-style shield decorated with turquoise mosaic from the collections of the Smithsonian Institution-National Museum of the American Indian. NMAI Catalog #10/8708. 
Credit:  Frances F. Berdan

 They also analyzed five tiles associated with Mixteca-style objects held by the Smithsonian's National Museum of the American Indian. The analyses revealed that turquoise artifacts had isotopic signatures consistent with geology of Mesoamerica, not the Southwestern United States.

"This work revises our understanding of these relatively rare objects and provides a new perspective on the availability of turquoise, which was a highly valued luxury resource in ancient Mesoamerica," said Thibodeau. The work is the result of a decade-long collaboration between archaeologists and isotope geochemists to understand the nature of turquoise circulation and trade across southwestern North America. In earlier published research, Thibodeau showed that isotopic signatures could distinguish among turquoise deposits across the southwestern U.S. and identified the geologic sources of turquoise artifacts from archaeological sites in Arizona and New Mexico.

This is a reconstructed turquoise mosaic disk from Offering 99 in the Templo Mayor.
 
Photo by Oliver Santana. Reproduced with permission from Editorial Raices.

Thibodeau said that long-standing assumption that Mesoamerican civilizations imported turquoise from the Southwest had not been fully substantiated with evidence and that the new geochemical measurements unveil a different story. "These findings potentially re-shape our understanding of both the nature and extent of long-distance contacts between Mesoamerican and Southwestern societies, said Thibodeau. "I hope this inspires people to be skeptical of claims."




Contacts and sources:
Christine Baksi
Dickinson College


Citation: Was Aztec and Mixtec turquoise mined in the American Southwest?
Alyson M. Thibodeau, Leonardo López Luján, David J. Killick, Frances F. Berdan, Joaquin Ruiz. Science Advances, 2018; 4 (6): eaas9370 DOI: 10.1126/sciadv.aas9370

What Saved The West Antarctic Ice Sheet 10,000 Years Ago Won’t Save It Today 

The retreat of the West Antarctic ice masses after the last Ice Age was reversed surprisingly about 10,000 years ago, scientists found. This is in stark contrast to previous assumptions. In fact, it was the shrinking itself that stopped the shrinking: relieved from the weight of the ice, the Earth crust lifted and triggered the re-advance of the ice sheet. However, this mechanism is much too slow to prevent dangerous sea-level rise caused by West Antarctica’s ice-loss in the present and near future. Only rapid greenhouse-gas emission reductions can.


West Antarctica: The maximum ice sheet extension is shown in green, the minimum extent 10,000 years ago in red, and the modern grounding line after the rebound in orange.
What saved the West Antarctic Ice Sheet 10,000 years ago will not save it today
 Fig.: Albrecht/PIK (cutout)

“The warming after the last Ice Age made the ice masses of West Antarctica dwindle,” says Torsten Albrecht from the Potsdam Institute for Climate Impact Research, one of the three lead authors of the study now published in the scientific journal Nature. “It retreated inland by more than 1,000 kilometers in a period of 1,000 years in large parts of this region – on geological time-scales, this is really high-speed. But now we detected that this process at some point got partially reversed. Instead of potential collapse, the ice sheet grew again by up to 400 kilometers. This is a limited, yet amazing self-induced stabilization. However, it took a whopping 10,000 years, up until now. Given the speed of current climate-change from burning fossil fuels, the mechanism we detected unfortunately does not work fast enough to save today’s ice sheets from melting and causing seas to rise.”

The team was able to find out why the rebound happened in West Antarctica. It is well-known that the Earth crust can get depressed by the weight of kilometer-thick ice on it – when the ice disappears, the ground lifts up. This is called isostatic rebound. However, this depends on the complicated characteristics of the Earth mantle in a given region – scientists for instance talk about viscosity. So far it was not known that the Earth crust in West Antarctica lifted in a way that made the shrinking ice re-advance. Previously, researchers assumed that after the last glacial maximum West Antarctica’s ice retreated continuously. Now it seems they have been generally right about the retreat, but have not fully grasped its dynamics.

Three sources of evidence: computer simulations, ice radar data, subglacial sediments
Credit: Potsdam Institute

“When I observed the re-growth in our numerical computer simulations of Western Antarctica, I first thought this might be a flaw – it looked so different from what you find in the text books,” says Torsten Albrecht. “So I started figuring out the involved interactions between the ice, ocean and Earth and their typical time scales.” In fact, the computer simulations turned out to help making sense out of observational data that other scientists found who had not relation to the work of the Potsdam modeling team – but were equally irritated at first about their respective findings.

During a trip to Antarctica to study ancient ice flows, Jonathan Kingslake and colleagues from Columbia University’s Lamont-Doherty Earth Observatory, based in New York, towed a radar device across the ice. To their surprise, the radar spotted cracks in the ice where there shouldn’t be any. “It was just bizarre,” says Kingslake, who is one of the study’s three lead-authors. “We hadn’t seen these kinds of structure near the base of an ice sheet before.” Further analyses of the signals revealed that the ice on the rocky ground must have been stretching or squishing rapidly, whereas this was so far considered a slow-moving area.

In yet another independent investigation, scientists looked into sediments recovered by drilling through many layers of ice to where it is grounded on rocks. The area was thought to be covered by grounded ice since the past Ice Age. But the team of Reed Scherer from Northern Illinois University, the third lead-author of the study now published, found organic material beneath the ice – the remains of tiny sea creatures long dead. This indicates that this area was connected to the ocean more recently than anybody thought. This is due to the rapid retreat and slow re-growth of the ice thousands of years ago.

Uplift won't help regrow the ice until long after coastal cities have felt the effects of sea level rise

A number of factors influences the ice-sheet behavior under warming. In the studied region sea mountains turned out to be rather important for the ice dynamics. The peaks of these mountains underneath the floating ice shelves reach up from the bottom of the ocean. When the bottom rises they can become ice rises within the ice shelf. Since they’re made of solid rock, they increase the stability of the ice sheet. The scientists call this a buttressing effect. Conditions for ice re-growth might be less favorable in other areas.

Yet it is the time-scale that is key in the end. “What happened roughly 10.000 years ago might not dictate where we’re going in our carbon dioxide-enhanced world, in which the oceans are rapidly warming in the Polar regions,” says Scherer. “If the ice sheet were to dramatically retreat now, triggered by anthropogenic warming, the uplift process won’t help regrow the ice sheet until long after coastal cities have felt the effects of sea level rise.”


Contacts and sources:
\
Potsdam Institute for Climate Impact Research (PIK)

Citation: Extensive retreat and re-advance of the West Antarctic Ice Sheet during the Holocene.
J. Kingslake, R. P. Scherer, T. Albrecht, J. Coenen, R. D. Powell, R. Reese, N. D. Stansell, S. Tulaczyk, M. G. Wearing, P. L. Whitehouse. Nature, 2018; DOI: 10.1038/s41586-018-0208-x