Sunday, April 29, 2018

U.S. Autism Rate Edges Up in New CDC Report

Researchers at the Johns Hopkins Bloomberg School of Public Health contributed to a new U.S. Centers for Disease Control and Prevention (CDC) report that finds the prevalence of autism spectrum disorder (ASD) among 11 surveillance sites as one in 59 among children aged 8 years in 2014 (or 1.7 percent). This marks a 15 percent increase from the most recent report two years ago, and the highest prevalence since the CDC began tracking ASD in 2000. Consistent with previous reports, boys were four times more likely to be identified with ASD than girls. The rate is one in 38 among boys (or 2.7 percent) and one in 152 among girls (or 0.7 percent).

ASD is a developmental disorder characterized by social and communication impairments, combined with limited interests and repetitive behaviors. Early diagnosis and intervention are key to improving learning and skills. Rates have been rising since the 1960s, but researchers do not know how much of this rise is due to an increase in actual cases. There are other factors that may be contributing, such as: increased awareness, screening, diagnostic services, treatment and intervention services, better documentation of ASD behaviors and changes in diagnostic criteria. 

Credit: National Institutes of Mental Health, National Institutes of Health

For this new report, the CDC collected data at 11 regional monitoring sites that are part of the Autism and Developmental Disabilities Monitoring (ADDM) Network in the following states: Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee and Wisconsin. The Maryland monitoring site is based at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

This is the sixth report by the ADDM Network, which has used the same surveillance methods for more than a decade. Estimated prevalence rates of ASD in the U.S. reported by previous data were:
  • one in 68 children in the 2016 report that looked at 2012 data
  • one in 68 children in the 2014 report that looked at 2010 data
  • one in 88 children in the 2012 report that looked at 2008 data
  • one in 110 children in the 2009 report that looked at 2006 data
  • one in 150 children in the 2007 report that looked at 2000 and 2002 data

“The estimated overall prevalence rates reported by ADDM at the monitoring sites have more than doubled since the report was first published in 2007,” says Dr. Li-Ching Lee, PhD, ScM, a psychiatric epidemiologist with the Bloomberg School’s departments of Epidemiology and Mental Health and the principal investigator for Maryland-ADDM. “Although we continue to see disparities among racial and ethnic groups, the gap is closing,” Lee says.

ASD prevalence was reported to be approximately 20 to 30 percent higher among white children as compared with black children in previous ADDM reports. In the current report, the difference has dropped to 7 percent. In addition, approximately 70 percent of children with ASD had borderline, average or above average intellectual ability, a proportion higher than that found in ADDM data prior to 2012.

Some trends in the latest CDC report remain similar, such as the greater likelihood of boys being diagnosed with ASD, the age of earliest comprehensive evaluation and presence of a previous ASD diagnosis or classification. Specifically, non-white children with ASD are being identified and evaluated at a later age than white children. The majority of children identified with ASD by the ADDM Network (80 percent) had a previous ASD diagnosis or a special educational classification.

In Maryland, the prevalence of ASD was higher than in the network as a whole. An estimated one in 50 children (2 percent) was identified as having ASD -- one in 31 among boys and one in 139 among girls. The data were derived from health and special education records of children who were eight years old and living in Baltimore County in 2014.

Lee notes, similar to previous reports, the vast majority of children identified with ASD in Maryland had a developmental concern in their records by age three (92 percent), but only 56 percent of them received a comprehensive evaluation by that age. “This lag may delay the timing for children with ASD to get diagnosed and to start receiving needed services,” says Lee, an associate director of the school’s Wendy Klag Center for Autism and Developmental Disabilities.

The causes of autism are not completely understood; studies show that both environment and genetics may play a role. The CDC recommends that parents track their child’s development and act quickly to get their child screened if they have a concern. Free checklists and information for parents, physicians and child care providers are available at

Contacts and sources:
Michelle Landrum
Johns Hopkins University Bloomberg School of Public Health

Citation: A full copy of the report, “Prevalence of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2014” is available on the CDC website here.

A copy of the Community Report with individual state statistics is available here.

Life-Size Holograms Set To Revolutionize Videoconferencing

A Queen’s University researcher will soon unveil TeleHuman 2 – the world’s first truly holographic videoconferencing system. TeleHuman2 allows people in different locations to appear before one another in life-size 3D – as if they were in the same room.

“People often think of holograms as the posthumous Tupac Shakur performance at Coachella 2012,” says Roel Vertegaal, Professor of Human-Computer Interaction at the Queen’s University School of Computing. “Tupac’s image, however, was not a hologram but a Pepper Ghost: A two-dimensional video projected on a flat piece of glass. With TeleHuman 2, we’re bringing actual holograms to life.”
Credit: Human Media Lab

Using a ring of intelligent projectors mounted above and around a retro-reflective, human-sized cylindrical pod, Dr. Vertegaal’s team has been able to project objects as light fields that can be walked around and viewed from all sides simultaneously by multiple users – much like Star Trek’s famed, fictional ‘holodeck’. Capturing the remote 3D image with an array of depth cameras, his team has ‘teleported’ live, 3D images of a human from one room to another – a feat that is set to revolutionize human telepresence. Because the display projects a light field with many images, one for every degree of angle, users need not wear a headset or 3D glasses to experience each other in augmented reality.
Credit: Human Media Lab

“Face-to-face interaction transfers an immense amount of non-verbal information,” says Dr. Vertegaal, who is also the head of the Queen’s Human Media Lab. “This information is lost in online tools, promoting poor online behaviours. Users miss the proxemics, gestures, facial expressions, and eye contact that bring nuance, emotional connotation and ultimately empathy to a conversation. TeleHuman 2 injects these missing elements into long-distance conversations with a realism that cannot be achieved with a Skype or Facetime video chat.”

Dr. Vertegaal first debuted the TeleHuman technology in 2012, but at that time the device only allowed for a single viewer to see the holographic projection correctly. With TeleHuman 2, multiple participants are able to see their holographic friend or colleague, each from their individual perspective. To test the system, Dr. Vertegaal had users judge angles at which a robotic arrow, mounted on a tripod, was pointing whilst physically present in the room, and whilst rendered on the TeleHuman 2. They did not judge the angles between the real and the virtual representation as significantly different.

Credit: Human Media Lab

“In a professional environment like a meeting, our latest edition of TeleHuman technology will do wonders for attendees looking to address colleagues with eye contact or to more effectively manage turn taking” says Dr. Vertegaal. “But it has potential beyond professional situations. Think again of a large music festival, and now imagine a performer capable of appearing simultaneously, and in true 3D, on TeleHuman 2 devices throughout the venue – bringing a whole new level of audience intimacy to a performance. The TeleHuman technology could even mitigate environmental impacts of business travel – enabling organizations to conduct more engaging and effective meetings from a distance, rather than having to appear in person. “

Dr. Vertegaal and his collaborators presented TeleHuman 2 to the general public at the ACM CHI Conference on Human Factors in Computing Systems, the premier international conference on Human-Computer Interaction, in Montreal, Canada on April 25, 2018

Contacts and sources:
Dave Rideout
Queen's University

Citation: TeleHuman 2.0: A Cylindrical Light Field Teleconferencing System for Life-size 3D Human Telepresence
Daniel Gotsch, Xujing Zhang, Timothy Merritt, Roel Vertegaal.. Proceedings of CHI'18 Conference on Human Factors in Computing Systems, 2018; DOI: 10.1145/3173574.3174096

Desert Ants Use Their Sixth Sense to Navigate

Desert ants use the Earth's magnetic field for orientation, a new study has found which was conducted by scientists of the University of Würzburg. This provides ants the cue to find their way back to the nest.

Desert ants (Cataglyphis) spend the first weeks of their life exclusively in their dark underground nest. For around four weeks, they nurse the queen and the brood, dig tunnels, build chambers or tidy up. At some point, they leave the nest to start their outdoor career, working as foragers until their death.

Desert ants (Cataglyphis) at the nest entrance.

Credit: Pauline Fleischmann

Pirouettes lead the way

Before an ant sets out to forage, it has to calibrate its navigational system, however. For this purpose, the insects exhibit a rather peculiar behaviour during two to three days: They perform so-called learning walks to explore the vicinity of the nest entrance and frequently turn about their vertical body axes while doing so. High-speed video recordings show that the ants stop repeatedly during these pirouetting motions. What is special about the longest of these stopping phases is that at this moment the ants always look back precisely to the nest entrance, although they are unable to see the tiny hole in the ground.

Researchers from the Biocenter of the University of Würzburg have now made the surprising discovery that the desert ant uses the Earth's magnetic field as orientation cue during these calibration trips. This ability had been previously unknown for desert ants.

Publication in Current Biology

Pauline Fleischmann and Robin Grob, research assistants of Professor Wolfgang Rössler, who holds the Chair of Zoology II at the Biocentre of the University of Würzburg, conducted the tests in the summer of 2017. The scientists designed the experiment together with Professor Rüdiger Wehner from the Brain Research Institute of the University of Zurich and physicist Valentin Müller from the University of Würzburg. They present their research results in the current issue of the journal Current Biology.

"While they are foraging for food, desert ants venture several hundred metres away from their nest, pursuing a sinusoidal path that includes larger loops. Once they have found food, they return to the nest entrance in a straight line," Wolfgang Rössler describes the ants' astonishing navigational abilities. The researchers had known already that the ants rely on the position of the sun and landmarks as orientational cues and integrate this information with the steps travelled.

Credit: University of Würzburg

Experiments in Greece

Recent research results have shown, however, that the desert ant also looks back to the nest entrance during its learning walks in the absence of solar information or landscape cues. "This sparked the idea that the insects might navigate using the Earth's magnetic field as a cue, as some birds do," Pauline Fleischmann says.

To confirm their hypothesis, the researchers travelled to the south of Greece where Cataglyphis ants are native. They took a 1.5-m-high pair of Helmholtz coils with them. A defined current passed through the coils creates an almost homogeneous, precisely known magnetic field in between the coils. This enabled the researchers to study the behaviour of the desert ants during their learning walks in their natural habitat under controlled conditions.

A surprising outcome

The result was unambiguous: When the scientists changed the orientation of the magnetic field, the desert ants no longer looked towards the real nest entrance but towards a predictable new location – the fictive nest entrance. "Their path integration provides them with a new vector to the nest based on the information of the magnetic field," Wolfgang Rössler explains. The scientists admit that they had been surprised by this finding. They say that although individual ant species are known to respond to changes in the magnetic field under certain conditions, the necessity and distinct influence on navigation in Cataglyphis ants was unexpected.

With this result the researchers have "opened a new door which raises a lot of further questions." One of them is: "When do desert ants use their magnetic sense?" It might well be that they already rely on it during the first weeks of their life which they spend underground. After all, a navigational aid can be quite useful in total darkness. But this is only a hypothesis at this point.

Interesting for neuroscience, computer science and robotics

The second question the scientists want to tackle is how and whether the ants switch between the different navigational cues - the position of the sun, landmarks and the magnetic field. Experienced foragers are already known to perform re-learning walks when they are forced to do so, for example by changing the environment at the nest entrance. It is unclear, however, whether they rely on magnetic field cues again in this case or whether they use their solar compass as during the foraging trips.

And ultimately, there is of course the overarching question of where the magnetic field sensor is located and how it works. According to Wolfgang Rössler, this question takes you deep into the field of orientational and navigational research in insects. How does the comparably small ant brain manage to store navigational information on the position of the sun, the magnetic field and landmarks and integrate this information with distance data from their step counter? Rössler believes that this question goes far beyond the field of behavioural research and neurosciences and is of great interest for computer science and robotics, too.

Contacts and sources:
Gunnar Bartsch
Prof. Dr. Wolfgang Rössler, Department of Zoology II
University of Würzburg

Citation: The geomagnetic field is a compass cue in Cataglyphis ant navigation. Pauline Nikola Fleischmann, Robin Grob, Valentin Leander Müller, Rüdiger Wehner, Wolfgang Rössler. Current Biology (2018),

Horses Remember Facial Expressions of People They’ve Seen Before

A study by the Universities of Sussex and Portsmouth reveals that horses can read and then remember people’s emotional expressions, enabling them to use this information to identify people who could pose a potential threat.

Published Thursday 26 April 2018 in the journal, Current Biology, the paper ‘Animals remember previous facial expressions that specific humans have exhibited’ is authored by a team of psychologists, co-led by Professor Karen McComb from the University of Sussex and Dr Leanne Proops, from the University of Portsmouth – both specialists in animal behaviour.
A researcher with neutral facial expression
Credit: University of Sussex

The research team conducted controlled experiments in which domestic horses were presented with a photograph of an angry or happy human face and several hours later saw the actual person who had exhibited the expression, now in an emotionally neutral state. This short-term exposure to the photograph of a person’s facial expression was enough to generate clear differences in subsequent responses upon meeting that individual in the flesh later the same day.

The study found that despite the humans being in a neutral state during the live meeting, the horses’ gaze direction revealed that they perceived the person more negatively if they had previously seen them looking angry in the photograph rather than happy.

Previous research, including at University of Sussex, has shown that animals tend to view negative events with their left eye due to the right brain hemisphere’s specialisation for processing threatening stimuli (information from the left eye is processed in the right hemisphere). I

mportantly, in the current experiment the humans did not know which photographs the horses had previously seen, to avoid any risk of behaving differently themselves. Also the differences in reaction only applied to the person the horses had actually seen in the photograph and were not given to a different person.

Professor McComb from the University of Sussex comments on the findings: "What we've found is that horses can not only read human facial expressions but they can also remember a person's previous emotional state when they meet them later that day – and, crucially, that they adapt their behaviour accordingly. Essentially horses have a memory for emotion.”

Co-lead author Dr Proops, of the University of Portsmouth, said: "We know that horses are socially intelligent animals, but this is the first time any mammal has been shown to have this particular ability. What's very striking is that this happened after just briefly viewing a photograph of the person with a particular emotional expression – they did not have a strongly positive or negative experience with the person."

Although past research (including that conducted by the University of Sussex) has demonstrated that horses can recognise human facial expressions, this is the first time that it has been shown that they can remember emotional experiences with specific individuals. This ability could have clear benefits for social bonding and aggression avoidance when these individuals are encountered again.

Contacts and sources:
Anna Ford
University of Sussex

Citation: Animals Remember Previous Facial Expressions that Specific Humans Have Exhibited.
Leanne Proops, Kate Grounds, Amy Victoria Smith, Karen McComb. Current Biology, 2018; DOI: 10.1016/j.cub.2018.03.035

Strange Underwater Phenomenon Like Russian Matryoshka Dolls within Dolls

Researchers at Utah State University are sending cascades of water into a tank to uncover a mystery of fluid dynamics.

After a yearlong research study, the team of engineers and fluid dynamicists uncovered the physics behind a unique underwater phenomenon that’s been likened to the Matryoshka doll — the traditional Russian doll within a doll.

In a study published last week in the Journal of Fluid Mechanics, researchers from USU’s Splash Lab describe what happens when rapid-succession water droplets impact a calm surface and create a cavity of air beneath the water.

“When a stream of droplets hits the surface, it pulls air under and creates an air-filled cavity,” says lead author and PhD candidate Nathan Speirs. “The shapes of the cavities vary based on the impact parameters such as the diameter of the droplet and the speed at impact.”

Researchers at USU’s Splash Lab uncovered the physics behind a unique underwater phenomenon that’s been likened to the Matryoshka doll — the traditional Russian doll within a doll.
Credit: Chris Mabey

When a continuous stream of water — a jet — impacts the water surface, it forms a cylindrical-shaped, deep, narrow cavity. When slow-succession droplets impact the water, they form individual cavities that close and collapse before the next droplet hits. The Splash Lab team wanted to know what happens when rapid-succession droplets impact the water. The result is a unique series of cavities within cavities that create a ribbed appearance.

“If the frequency of the falling droplets is high enough, the drops hit the same spot and create nested cavities,” said Speirs. “Each successive droplet forms a cavity at the base of the preceding cavity.”

Distinguishing the threshold between high and low frequency is a key part of the findings. Speirs says there has never been a number that defines that threshold. So he and his team developed one.

“We can define the types of cavities based on a new dimensionless number we call the Matryoshka number. If the number is less than one, the cavity will collapse before the next droplet hits. If it’s above one, we predict to see the formation of nested cavities.”

The researchers say their study offers new applications to everyday life.

“It has been known for a long time that a jet of fluid transitions into a stream of droplets just a few inches from the source of the jet,” said co-author and USU Associate Professor Tadd Truscott. “This means that when common daily jets impact a pool of water — such as water from a faucet into a kitchen sink or a stream of urine falling into a toilet — the droplet streams create cavities similar to those we’re studying at the Splash Lab.”

Understanding the nuances of splash types could lead to devices that reduce splash back and provide cleaner environments.

In industry, a more thorough understanding of this never-before-explained aspect of fluid dynamics could lead to advances in manufacturing chemicals and pharmaceuticals. Speirs says the findings are especially useful for developing safer and more efficient processes in which splash back is a concern.

Contacts and sources:
Dr. Tadd Truscott – Dept. of Mechanical and Aerospace Engineering
Utah State University

Citation: The water entry of multi-droplet streams and jets.
Nathan B. Speirs, Zhao Pan, Jesse Belden, Tadd T. Truscott. J
ournal of Fluid Mechanics, 2018; 844: 1084 DOI: 10.1017/jfm.2018.204

Researchers 3D Print Electronics and Cells Directly on Skin

In a groundbreaking new study, researchers at the University of Minnesota used a customized, low-cost 3D printer to print electronics on a real hand for the first time. The technology could be used by soldiers on the battlefield to print temporary sensors on their bodies to detect chemical or biological agents or solar cells to charge essential electronics.

Researchers also successfully printed biological cells on the skin wound of a mouse. The technique could lead to new medical treatments for wound healing and direct printing of grafts for skin disorders.

One of the key innovations of the new 3D-printing technique on skin is that the printer uses computer vision to track and adjust to movements in real-time.
Printing on hand
Credit: McAlpine group, University of Minnesota

The research study was published on the inside back cover of the academic journal Advanced Materials.

“We are excited about the potential of this new 3D-printing technology using a portable, lightweight printer costing less than $400,” said Michael McAlpine, the study’s lead author and the University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering. “We imagine that a soldier could pull this printer out of a backpack and print a chemical sensor or other electronics they need, directly on the skin. It would be like a ‘Swiss Army knife’ of the future with everything they need all in one portable 3D printing tool.”

One of the key innovations of the new 3D-printing technique is that this printer can adjust to small movements of the body during printing. Temporary markers are placed on the skin and the skin is scanned. The printer uses computer vision to adjust to movements in real-time.

“No matter how hard anyone would try to stay still when using the printer on the skin, a person moves slightly and every hand is different,” McAlpine said. “This printer can track the hand using the markers and adjust in real-time to the movements and contours of the hand, so printing of the electronics keeps its circuit shape.”

Another unique feature of this 3D-printing technique is that it uses a specialized ink made of silver flakes that can cure and conduct at room temperature. This is different from other 3D-printing inks that need to cure at high temperatures (up to 100 degrees Celsius or 212 degrees Fahrenheit) and would burn the hand.

To remove the electronics, the person can simply peel off the electronic device with tweezers or wash it off with water.

In addition to electronics, the new 3D-printing technique paves the way for many other applications, including printing cells to help those with skin diseases. McAlpine’s team partnered with University of Minnesota Department of Pediatrics doctor and medical school Dean Jakub Tolar, a world-renowned expert on treating rare skin disease. The team successfully used a bioink to print cells on a mouse skin wound, which could lead to advanced medical treatments for those with skin diseases.

“I’m fascinated by the idea of printing electronics or cells directly on the skin,” McAlpine said. “It is such a simple idea and has unlimited potential for important applications in the future.”

In addition to McAlpine and Tolar, the University of Minnesota team includes Ph.D. students Zhijie Zhu and Xiaoxiao Fan and postdoctoral researcher Shuang-Zhuang Guo from the Department of Mechanical Engineering in the College of Science and Engineering; and research staff Cindy Eide and Tessa Hirdler from the Department of Pediatrics in the Medical School.

This study was funded by grants from the National Institutes of Health and state-funded Regenerative Medicine Minnesota. In addition, the first author of the paper Zhijie Zhu was funded by a University of Minnesota Interdisciplinary Doctoral Fellowship.

Contacts and sources:
Lacey Nygard
University of Minnesota

Citation: “3D Printed Functional and Biological Materials on Moving Freeform Surfaces,”  Advanced Materials website.

Get a Grip: What Hand Strength Says About Marriage Prospects and Mortality

Researchers at Columbia University’s Mailman School of Public Health and the Columbia Aging Center found men with a stronger grip were more likely to be married than men with weaker grips. Grip strength was not a factor in the marital status of women. The findings are published online in the journal SSM-Population Health.

Grip strength is an established measure of health and has previously been linked to one’s ability to cope independently and predicts the risk of cardiovascular diseases and mortality.

“Our results hint that women may be favoring partners who signal strength and vigor when they marry,” said Vegard Skirbekk, PhD, professor, Columbia Aging Center and Mailman School professor of Population and Family Health. “If longer-lived women marry healthier men, then both may avoid or defer the role of caregiver, while less healthy men remain unmarried and must look elsewhere for assistance.”

Using a population-based study of 5,009 adults from the Norwegian city of Tromsø, the researchers examined the relationship of marital status to grip strength in two successive groups of people: those born 1923-35 and 1936-48, assessing the association between respondents’ marital status and grip strength when respondents were aged 59 to 71. These data were matched with the Norwegian national death registry. Handgrip strength was assessed using a vigorimeter, a device that asks participants to squeeze a rubber balloon.

Handshake (Workshop Cologne '06).jpeg
Credit: Tobias Wolter / Wikimedia Commons

Grip strength is particularly important for older adults, and has implications for a host of health risks—for heart disease and factures, physical mobility, the capacity to be socially active and healthy, and to enjoy a good quality of life. At the same time, marriage confers many of these same benefits.

The researchers found greater numbers of unmarried men with low grip strength in the second cohort—those born 1936-48—than in the first cohort, reflecting societal trends that have increasingly deemphasized the importance of marriage. “In recent decades, women are less dependent on men economically. At the same time, men have a growing ‘health dependence’ on women,” says Skirbekk. “The fact that many men are alone with a weak grip—a double burden for these men who lack both strength and a lack of support that comes from being married—suggests that more attention needs to be given to this group, particularly given their relatively poor health.”

Policies to help this population might include housing arrangements that encourage social interaction and counselling to better prepare these individuals for old age and information on how to avoid negative health consequences of independent living. “New technologies may potentially offset some of the limitations that low grip strength may imply,” says Skirbekk. “Social policies could also increasingly target this group by providing financial support for those who suffer the double-burden of low strength and lack of spousal support.”

Contacts and sources:
Stephanie Berger
Columbia University's Mailman School of Public Health

Citation: Vegard Skirbekk et al, Women's Spousal Choices and a Man's Handshake: Evidence from a Norwegian Study of Cohort Differences, SSM - Population Health (2018). DOI: 10.1016/j.ssmph.2018.04.004  Co-authors are Melissa Hardy, Pennsylvania State University and Bjørn Heine Strand, Norwegian Institute of Public Health.

Inexpensive Bionic Arms Provide a Sense of Touch

Losing an arm doesn’t have to mean losing all sense of touch, thanks to prosthetic arms that stimulate nerves with mild electrical feedback.

University of Illinois researchers have developed a control algorithm that regulates the current so a prosthetics user feels steady sensation, even when the electrodes begin to peel off or when sweat builds up.

“We’re giving sensation back to someone who’s lost their hand. The idea is that we no longer want the prosthetic hand to feel like a tool, we want it to feel like an extension of the body,” said Aadeel Akhtar, an M.D./Ph.D. student in the neuroscience program and the medical scholars program at the University of Illinois. Akhtar is the lead author of a paper describing the sensory control module, published in Science Robotics, and the founder and CEO of PSYONIC, a startup company that develops low-cost bionic arms.

Aadeel Akhtar, an M.D./Ph.D. student at Illinois, developed a control algorithm to give prosthetic arm users reliable sensory feedback.
Aadeel Akhtar, an M.D./Ph.D. student at Illinois, developed a control algorithm to give prosthetic arm users reliable sensory feedback.
Photo by L. Brian Stauffer

“Commercial prosthetics don’t have good sensory feedback. This is a step toward getting reliable sensory feedback to users of prosthetics,” he said.

Prosthetic arms that offer nerve stimulation have sensors in the fingertips, so that when the user comes in contact with something, an electrical signal on the skin corresponds to the amount of pressure the arm exerts. For example, a light touch would generate a light sensation, but a hard push would have a stronger signal.

Timothy Bretl is part of the Coordinated Science Laboratory at Illinois.
Photo by L. Brian Stauffer

However, there have been many problems with giving users reliable feedback, said aerospace engineering professor Timothy Bretl, the principal investigator of the study. During ordinary wear over time, the electrodes connected to the skin can begin to peel off, causing a buildup of electrical current on the area that remains attached, which can give the user painful shocks. Alternately, sweat can impede the connection between the electrode and the skin, so that the user feels less or even no feedback at all.

“A steady, reliable sensory experience could significantly improve a prosthetic user’s quality of life,” Bretl said.

The controller monitors the feedback the patient is experiencing and automatically adjusts the current level so that the user feels steady feedback, even when sweating or when the electrodes are 75 percent peeled off.

A patient performs various everyday tasks with a sensory control module integrated with his prosthetic arm.

Photos courtesy of Aadeel Akhtar

The researchers tested the controller on two patient volunteers. They performed a test where the electrodes were progressively peeled back and found that the control module reduced the electrical current so that the users reported steady feedback without shocks. They also had the patients perform a series of everyday tasks that could cause loss of sensation due to sweat: climbing stairs, hammering a nail into a board and running on an elliptical machine.

“What we found is that when we didn’t use our controller, the users couldn’t feel the sensation anymore by the end of the activity. However, when we had the control algorithm on, after the activity they said they could still feel the sensation just fine,” Akhtar said.

Adding the controlled stimulation module would cost much less than the prosthetic itself, Akhtar said. "Although we don't know yet the exact breakdown of costs, our goal is to have it be completely covered by insurance at no out-of-pocket costs to users."

The group is working on miniaturizing the module that provides the electrical feedback, so that it fits inside a prosthetic arm rather than attaching to the outside. They also plan to do more extensive patient testing with a larger group of participants.

“Once we get a miniaturized stimulator, we plan on doing more patient testing where they can take it home for an extended period of time and we can evaluate how it feels as they perform activities of daily living. We want our users to be able to reliably feel and hold things as delicate as a child's hand,” Akhtar said. “This is a step toward making a prosthetic hand that becomes an extension of the body rather than just being another tool.”

The National Institutes of Health and the National Science Foundation supported this work.

Contacts and sources:
Liz Ahlberg Touchstone University of Illinois at Urbana-Champaign

Citation: Controlling sensation intensity for electrotactile stimulation in human-machine interfaces.
Aadeel Akhtar, Joseph Sombeck, Brandon Boyce, Timothy Bretl. Science Robotics, 2018; 3 (17): eaap9770 DOI: 10.1126/scirobotics.aap9770

Mercury's Thin Crust Is Denser Than Aluminum and It's Core Is 60% of Planet Volume

Mercury is small, fast and close to the sun, making the rocky world challenging to visit. Only one probe has ever orbited the planet and collected enough data to tell scientists about the chemistry and landscape of Mercury's surface. Learning about what is beneath the surface, however, requires careful estimation.

After the probe's mission ended in 2015, planetary scientists estimated Mercury's crust was roughly 22 miles thick. One University of Arizona scientist disagrees.

Using the most recent mathematical formulas, Lunar and Planetary Laboratory associate staff scientist Michael Sori estimates that the Mercurial crust is just 16 miles thick and is denser than aluminum. His study, "A Thin, Dense Crust for Mercury," will be published May 1 in Earth and Planetary Science Letters and is currently available online.

This image of Mercury was created using infrared, red and violet filters that capture wavelengths both visible and invisible to the human eye; the colors shown here are only slightly different from what the human eye would see. 
This image of Mercury was created using infrared, red and violet filters that capture wavelengths both visible and invisible to the human eye; the colors shown here are only slightly different from what the human eye would see. (Image credit: NASA/Johns Hopkins University APL/Carnegie Institute of Washington)
Image credit: NASA/Johns Hopkins University APL/Carnegie Institute of Washington

Sori determined the density of Mercury’s crust using data collected by the Mercury Surface, Space Environment and Geochemistry Ranging (MESSENGER) spacecraft. He created his estimate using a formula developed by Isamu Matsuyama, a professor in the Lunar and Planetary Laboratory, and University of California Berkeley scientist Douglas Hemingway.

Sori's estimate supports the theory that Mercury's crust formed largely through volcanic activity. Understanding how the crust was formed may allow scientists to understand the formation of the entire oddly structured planet.

“Of the terrestrial planets, Mercury has the biggest core relative to its size,” Sori said.

The United States Geologic Survey released this topographic map of Mercury in 2016. The highest elevations are colored red, and the lowest elevations are colored dark blue.

Mercury's core is believed to occupy 60 percent of the planet’s entire volume. For comparison, Earth’s core takes up roughly 15 percent of its volume. Why is Mercury’s core so large?

“Maybe it formed closer to a normal planet and maybe a lot of the crust and mantle got stripped away by giant impacts,” Sori said. “Another idea is that maybe, when you're forming so close to the sun, the solar winds blow away a lot of the rock and you get a large core size very early on. There’s not an answer that everyone agrees to yet.”

Sori’s work may help point scientists in the right direction. Already, it has solved a problem regarding the rocks in Mercury's crust.

Mercury's Mysterious Rocks

When the planets and Earth's moon formed, their crusts were born from their mantles, the layer between a planet's core and crust that oozes and flows over the course of millions of years. The volume of a planet's crust represents the percentage of mantle that was turned into rocks.

Before Sori's study, estimates of the thickness of Mercury's crust led scientists to believe 11 percent of the planet's original mantle had been turned into rocks in the crust. For the Earth's moon – the celestial body closest in size to Mercury – the number is lower, near 7 percent.

"The two bodies formed their crusts in very different ways, so it wasn't necessarily alarming that they didn't have the exact same percentage of rocks in their crust," Sori said.

Though Mercury may look drab to the human eye, different minerals appear in a rainbow of colors in this image from NASA's MESSENGER spacecraft. 
Image credit: NASA/Johns Hopkins University APL/Carnegie Institution of Washington

The moon's crust formed when less dense minerals floated to the surface of an ocean of liquid rock that became the body's mantle. At the top of the magma ocean, the moon's buoyant minerals cooled and hardened into a "flotation crust." Eons of volcanic eruptions coated Mercury's surface and created its "magmatic crust."

Explaining why Mercury created more rocks than the moon did was a scientific mystery no one had solved. Now, the case can be closed, as Sori's study places the percentage of rocks in Mercury's crust at 7 percent. Mercury is no better than the moon at making rocks.

Sori solved the mystery by estimating the crust's depth and density, which meant he had to find out what kind of isostasy supported Mercury's crust.

Determining Density and Depth

The most natural shape for a planetary body to take is a smooth sphere, where all points on the surface are an equal distance from the planet's core. Isostasy describes how mountains, valleys and hills are supported and kept from flattening into smooth plains.

There are two main types isostasy: Pratt and Airy. Both focus on balancing the masses of equally sized slices of the planet. If the mass in one slice is much greater than the mass in a slice next to it, the planet’s mantle will ooze, shifting the crust on top of it until the masses of every slice are equal.

Pratt isostasy states that a planet’s crust varies in density. A slice of the planet that contains a mountain has the same mass as a slice that contains flat land, because the crust that makes the mountain is less dense than the crust that makes flat land. In all points of the planet, the bottom of the crust floats evenly on the mantle.

Until Sori completed his study, no scientist had explained why Pratt isostasy would or wouldn't support Mercury's landscape. To test it, Sori needed to relate the planet’s density to its topography. Scientists had already constructed a topographic map of Mercury using data from MESSENGER, but a map of density didn't exist. So Sori made his own using MESSENGER's data about the elements found on Mercury's surface.

“We know what minerals usually form rocks, and we know what elements each of these minerals contain. We can intelligently divide all the chemical abundances into a list of minerals," Sori said of the process he used to determine the location and abundance of minerals on the surface. "We know the densities of each of these minerals. We add them all up, and we get a map of density.”

Sori then compared his density map with the topographic map. If Pratt isostasy could explain Mercury’s landscape, Sori expected to find high-density minerals in craters and low-density minerals in mountains; however, he found no such relationship. On Mercury, minerals of high and low density are found in mountains and craters alike.

With Pratt isostasy disproven, Sori considered Airy isostasy, which has been used to make estimates of Mercury's crustal thickness. Airy isostasy states that the depth of a planet's crust varies depending on the topography.

"If you see a mountain on the surface, it can be supported by a root beneath it," Sori said, likening it to an iceberg floating on water.

The tip of an iceberg is supported by a mass of ice that protrudes deep underwater. The iceberg contains the same mass as the water it displaces. Similarly, a mountain and its root will contain the same mass as the mantle material being displaced. In craters, the crust is thin, and the mantle is closer to the surface. A wedge of the planet containing a mountain would have the same mass as a wedge containing a crater.

“These arguments work in two dimensions, but when you account for spherical geometry, the formula doesn’t exactly work out,” Sori said.

The formula recently developed by Matsuyama and Hemingway, though, does work for spherical bodies like planets. Instead of balancing the masses of the crust and mantle, the formula balances the pressure the crust exerts on the mantle, providing a more accurate estimate of crustal thickness.

Sori used his estimates of the crust's density and Hemingway and Matsuyama's formula to find the crust's thickness. Sori is confident his estimate of Mercury's crustal thickness in its northern hemisphere will not be disproven, even if new data about Mercury is collected. He does not share this confidence about Mercury's crustal density.

MESSENGER collected much more data on the northern hemisphere than the southern, and Sori predicts the average density of the planet's surface will change when density data is collected over the entire planet. He already sees the need for a follow-up study in the future.

The next mission to Mercury will arrive at the planet in 2025. In the meantime, scientists will continue to use MESSENGER data and mathematical formulas to learn everything they can about the first rock from the sun.

Contacts and sources:
Emily Walla
University of Arizona

Citation: A thin, dense crust for Mercury.
Michael M. Sori. Earth and Planetary Science Letters, 2018; 489: 92 DOI: 10.1016/j.epsl.2018.02.033

Einstein-Podolsky-Rosen Paradox Observed in Many-Particle System for The First Time

Physicists from the University of Basel have observed the quantum mechanical Einstein-Podolsky-Rosen paradox in a system of several hundred interacting atoms for the first time. The phenomenon dates back to a famous thought experiment from 1935. It allows measurement results to be predicted precisely and could be used in new types of sensors and imaging methods for electromagnetic fields. The findings were recently published in the journal Science.

How precisely can we predict the results of measurements on a physical system? In the world of tiny particles, which is governed by the laws of quantum physics, there is a fundamental limit to the precision of such predictions. This limit is expressed by the Heisenberg uncertainty relation, which states that it is impossible to simultaneously predict, for example, the measurements of a particle’s position and momentum, or of two components of a spin, with arbitrary precision.

A cloud of atoms is held above a chip by electromagnetic fields. The EPR paradox was observed between the spatially separated regions A and B 
A cloud of atoms is held above a chip by electromagnetic fields. The EPR paradox was observed between the spatially separated regions A and B (Illustration: University of Basel, Department of Physics)
Illustration: University of Basel, Department of Physics

A paradoxical decrease in uncertainty

In 1935, however, Albert Einstein, Boris Podolsky, and Nathan Rosen published a famous paper in which they showed that precise predictions are theoretically possible under certain circumstances. To do so, they considered two systems, A and B, in what is known as an “entangled” state, in which their properties are strongly correlated.

In this case, the results of measurements on system A can be used to predict the results of corresponding measurements on system B with, in principle, arbitrary precision. This is possible even if systems A and B are spatially separated. The paradox is that an observer can use measurements on system A to make more precise statements about system B than an observer who has direct access to system B (but not to A).

First observation in a many-particle system

In the past, experiments have used light or individual atoms to study the EPR paradox, which takes its initials from the scientists who discovered it. Now, a team of physicists led by Professor Philipp Treutlein of the Department of Physics at the University of Basel and the Swiss Nanoscience Institute (SNI) has successfully observed the EPR paradox using a many-particle system of several hundred interacting atoms for the first time.

The experiment used lasers to cool atoms to just a few billionths of a degree above absolute zero. At these temperatures, the atoms behave entirely according to the laws of quantum mechanics and form what is known as a Bose-Einstein condensate – a state of matter that Einstein predicted in another pioneering paper in 1925. In this ultracold cloud, the atoms constantly collide with one another, causing their spins to become entangled.

The researchers then took measurements of the spin in spatially separated regions of the condensate. Thanks to high-resolution imaging, they were able to measure the spin correlations between the separate regions directly and, at the same time, to localize the atoms in precisely defined positions. With their experiment, the researchers succeeded in using measurements in a given region to predict the results for another region.

“The results of the measurements in the two regions were so strongly correlated that they allowed us to demonstrate the EPR paradox,” says PhD student Matteo Fadel, lead author of the study. “It’s fascinating to observe such a fundamental phenomenon of quantum physics in ever larger systems. At the same time, our experiments establish a link between two of Einstein’s most important works.”

On the path towards quantum technology

In addition to their basic research, the scientists are already speculating about possible applications for their discovery. For example, the correlations that are at the heart of the EPR paradox could be used to improve atomic sensors and imaging methods for electromagnetic fields. The development of quantum sensors of this kind is one objective of the National Centre of Competence in Research Quantum Science and Technology (NCCR QSIT), in which the team of researchers is actively involved.

Contacts and sources:
Prof. Dr. Philipp Treutlein
University of Basel

Citation: Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in Bose-Einstein condensates
Matteo Fadel, Tilman Zibold, Boris Décamps, Philipp Treutlein. Science, 2018; 360 (6387): 409 DOI: 10.1126/science.aao1850

How Asteroids Can Deliver Water Throughout the Solar System

New research shows that a surprising amount of water survives simulated asteroid impacts, a finding that may help explain how asteroids deposit water throughout the solar system.

Experiments using a high-powered projectile cannon show how impacts by water-rich asteroids can deliver surprising amounts of water to planetary bodies. The research, by scientists from Brown University, could shed light on how water got to the early Earth and help account for some trace water detections on the Moon and elsewhere.

Experiments using a high-powered projectile cannon suggest that asteroids can deliver surprising amounts of water when they smash into planetary bodies.
Credit: Schultz Lab / Brown University

“The origin and transportation of water and volatiles is one of the big questions in planetary science,” said Terik Daly, a postdoctoral researcher at Johns Hopkins University who led the research while completing his Ph.D. at Brown. “These experiments reveal a mechanism by which asteroids could deliver water to moons, planets and other asteroids. It’s a process that started while the solar system was forming and continues to operate today.”

The research is published in Science Advances.

The source of Earth’s water remains something of a mystery. It was long thought that the planets of the inner solar system formed bone dry and that water was delivered later by icy comet impacts. While that idea remains a possibility, isotopic measurements have shown that Earth’s water is similar to water bound up in carbonaceous asteroids. That suggests asteroids could also have been a source for Earth's water, but how such delivery might have worked isn’t well understood.

“Impact models tell us that impactors should completely devolatilize at many of the impact speeds common in the solar system, meaning all the water they contain just boils off in the heat of the impact,” said Pete Schultz, co-author of the paper and a professor in Brown’s Department of Earth, Environmental and Planetary Sciences. “But nature has a tendency to be more interesting than our models, which is why we need to do experiments.”

Hypervelocity impact experiments, like the one shown here, reveal key clues about how impacts deliver water to asteroids, moons, and planets. In this experiment, a water-rich impactor collides with a bone-dry pumice target at around 11,200 miles per hour. The target was designed to rupture partway through the experiment in order to capture materials for analysis. This high-speed video, taken at 130,000 frames per second, slows down the action, which in real time is over in less than a second.
Credit: Schultz Lab / Brown University

For the study, Daly and Schultz used marble-sized projectiles with a composition similar to carbonaceous chondrites, meteorites derived from ancient, water-rich asteroids. Using the Vertical Gun Range at the NASA Ames Research Center, the projectiles were blasted at a bone-dry target material made of pumice powder at speeds around 5 kilometers per second (more than 11,000 miles per hour). The researchers then analyzed the post-impact debris with an armada of analytical tools, looking for signs of any water trapped within it.

They found that at impact speeds and angles common throughout the solar system, as much as 30 percent of the water indigenous in the impactor was trapped in post-impact debris. Most of that water was trapped in impact melt, rock that’s melted by the heat of the impact and then re-solidifies as it cools, and in impact breccias, rocks made of a mish-mash of impact debris welded together by the heat of the impact.

The research gives some clues about the mechanism through which the water was retained. As parts of the impactor are destroyed by the heat of the collision, a vapor plume forms that includes water that was inside the impactor.

“The impact melt and breccias are forming inside that plume,” Schultz said. “What we’re suggesting is that the water vapor gets ingested into the melts and breccias as they form. So even though the impactor loses its water, some of it is recaptured as the melt rapidly quenches.”

Samples of impact glasses created during an impact experiment. In impact experiments, these glasses capture surprisingly large amounts of water delivered by water-rich, asteroid-like impactors.

Credit: Brown University

The findings could have significant implications for understanding the presence of water on Earth. Carbonaceous asteroids are thought to be some of the earliest objects in the solar system — the primordial boulders from which the planets were built. As these water-rich asteroids bashed into the still-forming Earth, it’s possible that a process similar to what Daly and Schultz found enabled water to be incorporated in the planet’s formation process, they say. Such a process could also help explain the presence of water within the Moon’s mantle, as research has suggested that lunar water has an asteroid origin as well.

The work could also explain later water activity in the solar system. Water found on the Moon’s surface in the rays of the crater Tycho could have been derived from the Tycho impactor, Schultz says. Asteroid-derived water might also account for ice deposits detected in the polar regions of Mercury.

“The point is that this gives us a mechanism for how water can stick around after these asteroid impacts,” Schultz said. “And it shows why experiments are so important because this is something that models have missed.”

The research was supported by NASA (NNX13AB75G), the National Science Foundation (DGE-1058262) and the NASA Rhode Island Space Grant (NNX15AI06H).

Contacts and sources:
Kevin Stacey
Brown University

Citation: The delivery of water by impacts from planetary accretion to present.
R. Terik Daly, Peter H. Schultz.  Science Advances, 2018; 4 (4): eaar2632 DOI: 10.1126/sciadv.aar2632

‘Infinitely’ Recyclable Polymer Has Practical Properties of Plastics

The world fell in love with plastics because they’re cheap, convenient, lightweight and long-lasting. For these same reasons, plastics are now trashing the Earth.

Colorado State University chemists have announced in the journal Science another major step toward waste-free, sustainable materials that could one day compete with conventional plastics. Led by Eugene Chen, professor in the Department of Chemistry, they have discovered a polymer with many of the same characteristics we enjoy in plastics, such as light weight, heat resistance, strength and durability. But the new polymer, unlike typical petroleum plastics, can be converted back to its original small-molecule state for complete chemical recyclability. This can be accomplished without the use of toxic chemicals or intensive lab procedures.

Eugene Chen’s lab at Colorado State University has developed a completely recyclable polymer.
recyclable polymerCredit: Bill Cotton/Colorado State University

Polymers are a broad class of materials characterized by long chains of chemically bonded, repeating molecular units called monomers. Synthetic polymers today include plastics, as well as fibers, ceramics, rubbers, coatings, and many other commercial products.
Building on fundamental knowledge

The work builds on a previous generation of a chemically recyclable polymer Chen’s lab first demonstrated in 2015. Making the old version required extremely cold conditions that would have limited its industrial potential. The previous polymer also had low heat resistance and molecular weight, and, while plastic-like, was relatively soft.

But the fundamental knowledge gained from that study was invaluable, Chen said. It led to a design principle for developing future-generation polymers that not only are chemically recyclable, but also exhibit robust practical properties.

Eugene Chen, professor of chemistry
Credit:  CSU

The new, much-improved polymer structure resolves the issues of the first-generation material. The monomer can be conveniently polymerized under environmentally friendly, industrially realistic conditions: solvent-free, at room temperature, with just a few minutes of reaction time and only a trace amount of catalyst. The resulting material has a high molecular weight, thermal stability and crystallinity, and mechanical properties that perform very much like a plastic. 

Most importantly, the polymer can be recycled back to its original, monomeric state under mild lab conditions, using a catalyst. Without need for further purification, the monomer can be re-polymerized, thus establishing what Chen calls a circular materials life cycle.

This piece of innovative chemistry has Chen and his colleagues excited for a future in which new, green plastics, rather than surviving in landfills and oceans for millions of years, can be simply placed in a reactor and, in chemical parlance, de-polymerized to recover their value – not possible for today’s petroleum plastics. Back at its chemical starting point, the material could be used over and over again – completely redefining what it means to “recycle.”

“The polymers can be chemically recycled and reused, in principle, infinitely,” Chen said.
Next steps

Chen stresses that the new polymer technology has only been demonstrated at the academic lab scale. There is still much work to be done to perfect the patent-pending monomer and polymer production processes he and colleagues have invented.

With the help of a seed grant from CSU Ventures, the chemists are optimizing their monomer synthesis process and developing new, even more cost-effective routes to such polymers. They’re also working on scalability issues on their monomer-polymer-monomer recycling setup, while further researching new chemical structures for even better recyclable materials.

“It would be our dream to see this chemically recyclable polymer technology materialize in the marketplace,” Chen said.

The paper’s first author is CSU research scientist Jian-Bo Zhu. Co-authors are graduate students Eli Watson and Jing Tang.

Chen’s co-authors, from left: Research scientist Jian-Bo Zhu, and graduate students Jing Tang and Eli Watson.

Credit: CSU

Contacts and sources:
Anne Manning 
Colorado State University (CSU)

Citation:  A synthetic polymer system with repeatable chemical recyclability.
Jian-Bo Zhu, Eli M. Watson, Jing Tang, Eugene Y.-X. Chen. Science, 2018; 360 (6387): 398 DOI: 10.1126/science.aar5498

Yellowstone National Park: A Guide to Life on Mars?

A University of Cincinnati geology student is helping NASA determine whether life existed on other planets.

Doctoral candidate Andrew Gangidine is working with UC geology professor Andrew Czaja to develop a marker for ancient bacterial life on Mars. The research could help scientists put to rest one of our most fundamental mysteries.

“We’re trying to answer the question: How rare is life in the universe?” Gangidine said.

Czaja, an assistant professor in UC's McMicken College of Arts and Sciences, serves on a NASA advisory committee that will decide where on Mars to send the next remote-controlled rover. Among other objectives, the rover will look for evidence that life once existed on the red planet. The advisory committee has narrowed the list of landing-site candidates to three and will recommend a finalist later this year.

UC graduate student Andrew Gangidine stands in front of a hot spring in Yellowstone National Park.

Photo by Annie Gangidine

Meanwhile, Gangidine is studying microbial life in silica hot springs to come up with a useful indicator of life on Mars. For the past two years, he has conducted fieldwork in the geyser basins of Wyoming’s Yellowstone National Park to examine what elements are associated with bacteria that live in these geothermal pools.

“We want to remain objective. Some people think there has to be life on Mars,” Gangidine said. “Others think there certainly isn’t life on Mars. And either side has a good chance of being correct. Both have valid arguments. Which is why if we go there and don’t see anything, it won’t be ‘mission fail.’”

UC geologists studied steam cone geysers that deposit layers of silica over thousands of years.

Photo by Annie Gangidine

Gangidine presented his research April 25 at the Second International Mars Sample Return conference in Berlin, Germany.

UC geologists think if life ever existed on Mars, NASA might find evidence preserved somewhere around the red planet's geothermal areas.

Today, we know that life cannot exist on Mars, at least not on its dry surface. Solar radiation split most of its surface water into its elemental parts nearly 3 billion years ago when the red planet lost its protective magnetic field.

But scientists are debating whether life might exist somewhere deep underground, among pockets of water trapped around geothermal areas similar to Yellowstone’s geysers.

Finding evidence of life on Mars is surprisingly complicated.

If Mars ever sustained life, it’s possible that it was wiped out when most of its atmosphere vanished in the solar wind, Czaja said.

So NASA scientists must be prepared to look for fossil evidence of bacterial life dating back that far. Gangidine said the good news is that similar fossils of early bacterial life more than 3.5 billion years ago have been found on Earth. This makes him optimistic that if similar life ever existed on Mars, NASA has a chance of finding a fossil record of it.

“We can look at life being preserved in these silica deposits today. We have evidence of this happening throughout geologic time,” Gangidine said. “What we’re trying to do is catch fossilization as it happens. What happens to the microbes themselves? And what happens to the trace elements we think are associated with them while they’re alive?”

To unearth clues about ancient life on Mars, geologists look to hot springs such as those found in America’s first national park.

Gangidine and his colleagues need permits to collect samples in the park’s backcountry. But exploring the geyser basins can be tricky and dangerous. A tourist died in 2017 after falling into one of the basin’s boiling pools while hiking off-trail.

“These things really can strip the flesh off your bones,” Gangidine said. “At the bottom of hot springs we study you see skulls of bison and other animals that were unfortunate enough to wander too close.”

Gangidine’s team includes an experienced backcountry field researcher, UC postdoctoral fellow Jeff Havig who is now with the University of Minnesota. They pick their way carefully across the caldera. Sometimes, they can see where a bison’s hoof has broken through the thin crust to reveal steaming mud.

The geology work takes them across “quaking bogs,” a thin layer of peat and grass covering deep shifting mud. Gangidine was walking alongside a colleague on one such hike when he sank above his knees in the treacherous mire.

“Luckily, that place wasn’t super hot. But I was walking just a foot away from someone else. The ground can really change quickly,” he said. “When we go into these settings, we have to be very careful.”

Harvard University geologist T.A. Jaggar Jr. poses next to several brown bears that were asphyxiated by toxic fumes in Yellowstone's Death Gulch in this 1899 photo. Today, animals such as bison occasionally wander into low-lying areas of Yellowstone's geyser basin where they succumb to trapped toxic gases.
Photo by U.S. Geological Survey

Boiling acid and lava-like mud aren’t the only hazards for researchers in the geyser basins. They also have to be careful not to spend too long around the steam vents, which contain a mix of gases such as carbon dioxide, hydrogen sulfide and methane that can asphyxiate a person under the right conditions.

The U.S. Geological Survey documented this phenomenon in 1888 in part of the park nicknamed “Death Gulch,” a natural depression between two steep hills where toxic gases bubble up from Cache Creek. Harvard University geologist T.A. Jaggar Jr. returned to the area in 1899 and found six bears, an elk and various small animals that died apparently after succumbing to the toxic fumes.

But even in the fresh air, the gas rising from the ground can have a cumulative effect, Gangidine said.

“These hot springs emit a lot of gases you don’t want to breathe in. They bind to the hemoglobin that carries oxygen through your body. Breathing that in, you get very fatigued,” Gangidine said.

“That’s why we try to schedule a day out of the field for every three days we work in the field. If you’re there for four days, you can really feel like a zombie. It’s really hard to think, hard to move.”

A team of geologists stands near one of Yellowstone's famed hot springs. The deep blue color comes from the scattered light of the sun passing through the clear water.
A team of geologists stands near one of Yellowstone's famed hot springs. The deep blue color comes from the scattered light of the sun passing through the clear water. (Photo by Annie Gangidine)
Photo by Annie Gangidine

As a biology undergraduate at UC, Gangidine worked with UC biology professor Dennis Grogan to examine microbial life called extremophiles that live in hostile places such as Yellowstone’s acidic or alkaline hot springs. Now as a geologist, Gangidine is studying the fossils these hardy single-celled creatures leave behind.

“Hot springs make silica deposits that preserve life really well,” Gangidine said. “When left exposed on a planet’s surface, it doesn’t crystallize and doesn’t metamorphose. So these samples should be relatively well preserved if we find them.”

In UC professor Czaja’s geology lab, Gangidine peers through a microscope at slides he prepared from chunks of Yellowstone silica he took from a mountainous steam cone geyser.

The bacterial filaments from samples taken at the top of the geyser are full of color. But the older samples, some perhaps thousands of years old, are colorless, even if they hold their shape. So for more clues about this basic form of life, Gangidine subjects the bacterial samples to elemental analysis using a secondary ion mass spectrometer. The analysis renders the elements in vivid color: deep yellows, reds and greens representing chromium or gallium perhaps associated with the bacterial life.

If Gangidine finds a correlation between the concentrations and spatial distributions of particular elements and the bacteria, it might serve as a biosignature that scientists can use to identify past life on Mars.

“The reason we chose gallium is it’s not known to be associated with life. But when we look at the fossilized bacterial samples, we find it, so there must be something going on,” Gangidine said. “Do the bacteria store certain elements preferentially as opposed to what you would find elsewhere in these rocks?”

Spectroscopy reveals elements such as gallium in a bacterial sample taken from silica in Yellowstone National Park.

Credit: Andrew Gangidine

Gangidine is working with researchers in Australia, home to some of the world’s oldest fossils, some dating back 3.5 billion years.

“If I want to create a biosignature, I have to prove that it persists throughout time,” Gangidine said. “It exists in these relatively younger samples. But does it exist in these ancient samples, too? That will be crucial to figure out.”

Gangidine also plans to build an artificial hot spring in a lab aquarium using similar elements found in geysers. By introducing a super-saturation to the water, the excess silica will precipitate much the same way it does in nature. Then he can add trace chemicals associated with life and study what happens in a miniature world absent of life.

“To prove we found a biosignature, we have to prove the signature doesn’t occur without life,” he said.

“Gallium is the one we were surprised by,” Czaja said. “It is associated with silica near the bacteria but isn’t in the bacteria.”

Like Gangidine, Czaja got his start in the sciences by studying biology before pursuing a career in paleontology.

Czaja’s NASA advisory committee will meet in October to decide where on Mars they would like to send the rover among the three preferred destinations. The rover is tentatively slated for launch in July or August of 2020, arriving on Mars about seven months later.

“NASA tends to like to go new places to push the frontier. Geologists like to go back to the same places over and over to ask new questions,” Czaja said.

The rover will collect samples in sealed containers for shipping back to Earth in a later mission. So it could be many years before geologists such as Czaja and Gangidine know whether their hunches about where best to look for life on Mars were correct.

Helping to frame a question that you may never live to see answered is one of science’s most selfless pursuits, Czaja said.

“One thing I like about these NASA missions is the long-term thinking and planning,” he said. “People working on these projects now may never see the results. But they’re still willing to put in the work because it’s such a fascinating question.”

UC student Andrew Gangidine is looking for an elemental marker that could help NASA identify ancient life on Mars during its upcoming Mars 2020 mission.

Yellowstone National Park in Wyoming is home to one of the world's most active geothermal areas, featuring mud pots, erupting geysers and boiling springs like this one.

 Photo by Annie Gangidine

The Mars 2020 mission will not be a failure if scientists find no evidence of life. Quite the contrary, Gangidine said.

“If we find it, we can say maybe life is not that rare among planets,” Gangidine said. “But if we don’t find life in places that would be the most ideal and best preserved candidates, then maybe life is pretty rare.”

But if NASA does find evidence of life on Mars, that might suggest that sparking life from a primordial soup isn’t so extraordinary after all. And the first question will be how life on Mars compares to life on Earth, Czaja said. Was there a common ancestor?

“Maybe we’re all Martians,” Czaja said.

Any claim about the existence or absence of life on Mars will be subjected to worldwide scrutiny and skepticism. Czaja said researchers must be prepared to provide a wealth of evidence to fortify their findings.

“It’s not nearly enough to find something that looks like a bacterial cell,” Czaja said. “There are nonbiological things that could look like that. But if you have a cascade of traits — this and this and this added together — it’s hard to explain it any other way except for life.”

Contacts and sources:
Michael Miller
University of Cincinnati

Scientists Use Quantum “Spooky Action” to Entangle Objects You Can Actually See

Even in the odd world of quantum physics, the phenomenon known as entanglement—in which two objects become tied together although not physically connected—is among the hardest to comprehend. It’s equally difficult to achieve in the lab; scientists usually have to work very hard just to do it with single atoms.

But a UChicago physicist is among a group of researchers that announced April 26 in Nature that they had managed to entangle perhaps the largest items yet, at a whopping 20 microns across—about the diameter of a single human hair.

Scientists say that harnessing the mysterious property that Albert Einstein called “spooky action at a distance” is a crucial step toward exploiting quantum quirks for technology such as new kinds of sensors or computers.

“Entanglement is not just some academic curiosity; it’s also something you can harness as a basis for doing useful things with quantum mechanics,” said Prof. Aashish Clerk of the University of Chicago’s Institute for Molecular Engineering.

An illustration of an experiment where scientists entangled the vibrations of tiny drumheads, each the diameter of a human hair.
Credit: Aalto University / Petja Hyttinen & Olli Hanhirova, ARKH Architects.

Unfortunately for applications, entangled states are typically extremely fragile—especially so when they involve large objects. So Clerk and his former postdoc Matt Woolley (now at UNSW Sydney) developed a theoretical proposal for how to keep the motion of large objects entangled. Their approach involves involved coupling the objects to a specially designed circuit made out of a superconducting metal—a special material that can have zero electrical resistance, meaning that it conducts electricity perfectly. This circuit acts to keep the two objects in the special entangled quantum state: When they are disturbed and threaten to fall out of alignment, the circuit nudges the two objects back into the entangled state.

A group led by Mika Sillanpaa at Aalto University in Finland put the idea to the test. They used a circuit to entangle the motion of two aluminum plates, each one vibrating like a tiny drumhead. Not only did it work, but they were able to keep the plates entangled for times approaching an hour. (For most systems, the time you can maintain entanglement is measured in microseconds or even shorter.)

“Looking towards the future, there’s a lot of interest in using mechanical objects in quantum regimes for applications,” Clerk said. This includes powerful new kinds of sensors, with potential applications ranging from new ways to look inside the human body to even better methods to detect ripples of gravitational waves from faraway stars and black holes.

Such mechanical objects also could be a powerful way to integrate different systems to make up a quantum computer or quantum network, Clerk said. “Mechanical motion could be a kind of ‘bus’ for quantum information.”

Besides Aalto and UChicago, other scientists in the study hailed from Finland’s University of Jyväskylä and UNSW Canberra in Australia.

Contacts and sources:
University of Chicago

Citation: “Entangled massive mechanical oscillators.” Nature, Ockeloen-Korppi et al, April 26, 2018.

Funding: Academy of Finland, European Research Council, European Commission.

Algorithm Shaped News Landscape and the Rise of Disinformation

Fake news is not a new phenomenon at all; it is as old as the newspaper industry. The first occurrence of fake news was reported in the 16th century . It is only recently however that it has surged back onto our radar screens, in the wake of the digital transformation of news from offline to online distribution and the rise of social media as a news distribution channel.

On 26 April 2018 the European Commission took steps to tackle the spread and impact of online disinformation in Europe and ensure the protection of European values and democracies.

The Commission proposed an EU-wide Code of Practice on Disinformation, support to an independent network of fact-checkers, and concrete tools to stimulate quality journalism.

The JRC study on the digital transformation of news media and the rise of disinformation contributed to defining the tools for tackling disinformation online. The report contains an overview of the relevant economic research literature on the digital transformation of news markets and related impact on the quality of news.

The JRC study on the digital transformation of news media and the rise of disinformation contributed to defining the tools for tackling disinformation online.

Credit: EU 2018

Algorithm-driven platforms shape the news landscape

The report points out that two-thirds of online news consumers prefer to access it through algorithm-driven platforms such as search engines and news aggregators, and social media websites.

It also states that market power and revenue streams shifted from news publishers to platform operators who have the data to match readers, articles and ads.

The quality concerns in news are a result of not so much the shift from offline to online distribution, but rather the shift from direct access to newspapers to indirect algorithm-driven distribution of news. This is characterised by the mix of genuine edited news articles, user generated content and deliberately produced disinformation.

True news dwarf false news

Despite the much wider availability and accessibility of online news, user trust in news media, especially in online sources of news, is low and differs considerably by age, education and country. Traditional print and broadcasted news remain the most trusted sources.

True news audiences dwarf false news audiences, though fake news travels faster and further on social media sites, also across echo chambers and may capture consumer attention longer than true news. Research in this field, however, is only at the fledgling stage, with findings sensitive to the sample selection of false and real news sources.

Most studies analysed in the JRC report find limited impact of false news on political choices.

Are digital news market failing?

There are concerns about distribution platforms such as search engines, news aggregators and social media sites, because their main objective is not the provision of quality news but rather to maximize traffic and advertising revenue. They may weaken consumer trust and news brand recognition and facilitate the introduction of disinformation and false news into the market. This may contribute to news market failure when it becomes difficult for consumers to distinguish between good quality news and disinformation or fake news.

Disinformation detectives

The JRC is also carrying out extensive research on the issue of fake news. From identifying sources of disinformation to tracking trendy narratives, this work seeks to detect early such stories and prevent them from spreading.

The European Media Monitor (EMM) developed by JRC covers about 300,000 articles per day from traditional news sites. With such an overwhelming volume of information, specific software is necessary in order to classify the information by policy area, and to cluster it in order to find the top stories. However, the monitoring cannot rely on technology alone, human analysis is ultimately necessary.

The JRC has been working with the European External Action Service East StratComm Task Force, set up by the EEAS in 2015 to address pro-Kremlin disinformation. This surveillance allows capturing trends and ongoing narratives, for instance, that NATO was behind the protests in Ukraine or that the West is trying to attack Russia or to legalize pedophilia. 

Social media and bot accounts

The JRC is also developing monitoring to cover social media, including Twitter. Around 55 million tweets circulate daily through this platform. The JRC analyses a sample of 10% of them, in order to identify trends, to see how news can quickly "go viral", and to map communities based on the information users share and on how they interact with each other.

Another area of current research is the tonality of known fake news. Usually, balanced journalistic reporting presents positive and negative aspects, therefore the overall tonality is neutral. Disinformation articles, on the contrary, often push emotions to the extreme. On this topic, the JRC is organizing workshops with journalists, social media managers and policy officers, in order to help them understand the use of emotions by fake news sources.

Contacts and sources:
Barbara Piotrowska 
European Commission Joint Research Centre (JRC)

Citation: JRC study: The digital transformation of news media and the rise of disinformation and fake news

Saturday, April 28, 2018

Fungi Used as Tinder for Fires in Stone Age Spain

Inhabitants of the Neolithic community at la Draga (Banyoles, Girona) already used fungi to light or transport fires 7300 years ago. The discovery represents one of the oldest examples of technological use of fungi documented until now and is the result of several archaeological interventions at the site, which have also yielded an exceptional collection of these organisms, unique in all of prehistoric Europe.

The study of this atypical set of remains, published recently in the journal PLOS ONE, was conducted by Marian Berihuete-Azorín (Hohenheim University), Josep Girbal (UAB), Raquel Piqué (UAB), Antoni Palomo (Museum of Archaeology of Catalonia) and Xavier Terradas (CSIC-IMF).

"Despite the use of fire being well documented, at the la Draga site we had not yet found proof of the materials used to light or transport it. Data gathered points to the majority of fungi recovered were selected, taken to the forest surrounding the site, dried and stored, with the intention of using them as tinder. In addition, it was evident in two of the samples we analysed that they were being used for this purpose, which proved our hypothesis", explains Raquel Piqué, researcher at the UAB Department of Prehistory.

Sample of Ganoderma adspersum with signs of carbonisation.
 Photo: la Draga team

The site of la Draga is one of the exceptional examples for the study of archaeological remains, which remain under the phreatic level, and this has allowed researchers to recover up to 86 different individuals, some of them complete, and conduct a taxonomic study which allowed to verify the presence of six fungi species: Skeletocutis nivea, Coriolopsis gallica, Daedalea quercina, Daldinia concentrica, Ganoderma adspersum and Lenzites warnieri.

"Being able to recover these remains is extraordinary, given that their conservation as archaeological material is very difficult due to their easiness to decompose", adds Antoni Palomo, research at the MAC and the UAB.

The majority of fungi recovered at la Draga are polypore and can both grow on dead tree trunks and parasitise living trees. They are non-edible species which have been traditionally used to light fires, and are therefore known as "tinder-fungi". Their woody structure makes them high inflammable and therefore ideal for starting and transporting fire. Among the species used for this purpose there are Daedalea quercina, different kinds of Ganoderma, Coriolopsis gallica and Daldinia concentrica, all of them documented at la Draga. 

Tinder fungi was used to catch the sparks produced by hitting a siliceous rock against a mineral rich in ferric sulphide such as pyrite or marcasite. Researchers assure that the discovery makes La Draga an exceptional example for the study of fungi during Prehistory. It is one of the archaeological sites with a higher variety of fungi that has been retrieved till date.

Until now, the few archaeological discoveries of fungi belonged to sites in northern and central Europe, and only in a few cases was it possible to demonstrate technological uses. One of the most important was at the Mesolithic site of Starr Carr in England, in which samples were also interpreted as having been intentionally transported in order to be used as tinder fungi. Another notable example, but chronologically more recent than La Draga, are the remains transported by the iceman Ötzi as part of his equipment.

Importance of the Neolithic Site of la Draga

The remains studied form part a set of discoveries made at the Neolithic site of la Draga, located at the eastern shore of Lake Banyoles. The importance of this prehistoric settlement lies in the fact that it is one of the first enclaves where Neolithic farming societies decided to settle in the northeast of the Iberian Peninsula, about 7300 years ago, transforming the surroundings in order to carry out the agricultural and livestock practices necessary for their subsistence. The most outstanding feature at the site is the conservation of elements built with wood and other organic materials, an exceptional feat for such an early society and which contributes to a more complete comprehension of these first farming societies of the westernmost Mediterranean.

The site was discovered in 1990 and since then, different interventions have been carried out under the coordination of the Archaeological Museum of Banyoles and the participation of the Universitat Autònoma de Barcelona, the Spanish National Research Council (IMF, Barcelona) and the Museum of Archaeology of Catalonia.

The excavations are funded by a project granted by the Department of Culture of the Government of Catalonia, while the research project has received the support of the Spanish Ministry for Economy and Competitiveness through a project coordinated by the CSIC, the UAB, and Recercaixa.

Contacts and sources:
Maria Jesus Delgado 
Universitat Autònoma de Barcelona - UAB Barcelona