Friday, January 31, 2020

Brain Networks Come ‘Online’ During Adolescence to Prepare Teenagers for Adult Life

New brain networks come ‘online’ during adolescence, allowing teenagers to develop more complex adult social skills, but potentially putting them at increased risk of mental illness, according to new research published in the Proceedings of the National Academy of Sciences (PNAS).

Brain development during adolescence: red brain regions belong to the “conservative” pattern of adolescent development, while the blue brain regions belong to the “disruptive” pattern

Credit: Frantisek Vasa


Adolescence is a time of major change in life, with increasing social and cognitive skills and independence, but also increased risk of mental illness. While it is clear that these changes in the mind must reflect developmental changes in the brain, it has been unclear how exactly the function of the human brain matures as people grow up from children to young adults.

A team based in the University of Cambridge and University College London has published a major new research study that helps us understand more clearly the development of the adolescent brain.

The study collected functional magnetic resonance imaging (fMRI) data on brain activity from 298 healthy young people, aged 14-25 years, each scanned on one to three occasions about 6 to 12 months apart. In each scanning session, the participants lay quietly in the scanner so that the researchers could analyse the pattern of connections between different brain regions while the brain was in a resting state.

The team discovered that the functional connectivity of the human brain – in other words, how different regions of the brain ‘talk’ to each other – changes in two main ways during adolescence.

The brain regions that are important for vision, movement, and other basic faculties were strongly connected at the age of 14 and became even more strongly connected by the age of 25. This was called a ‘conservative’ pattern of change, as areas of the brain that were rich in connections at the start of adolescence become even richer during the transition to adulthood.

However, the brain regions that are important for more advanced social skills, such as being able to imagine how someone else is thinking or feeling (so-called theory of mind), showed a very different pattern of change. In these regions, connections were redistributed over the course of adolescence: connections that were initially weak became stronger, and connections that were initially strong became weaker. This was called a ‘disruptive’ pattern of change, as areas that were poor in their connections became richer, and areas that were rich became poorer.

By comparing the fMRI results to other data on the brain, the researchers found that the network of regions that showed the disruptive pattern of change during adolescence had high levels of metabolic activity typically associated with active re-modelling of connections between nerve cells.

Dr Petra Vértes, joint senior author of the paper and a Fellow of the mental health research charity MQ, said: “From the results of these brain scans, it appears that the acquisition of new, more adult skills during adolescence depends on the active, disruptive formation of new connections between brain regions, bringing new brain networks ‘online’ for the first time to deliver advanced social and other skills as people grow older.”

Professor Ed Bullmore, joint senior author of the paper and head of the Department of Psychiatry at Cambridge, said: “We know that depression, anxiety and other mental health disorders often occur for the first time in adolescence – but we don't know why. These results show us that active re-modelling of brain networks is ongoing during the teenage years and deeper understanding of brain development could lead to deeper understanding of the causes of mental illness in young people.”

Measuring functional connectivity in the brain presents particular challenges, as Dr František Váša, who led the study as a Gates Cambridge Trust PhD Scholar, and is now at King’s College London, explained.

“Studying brain functional connectivity with fMRI is tricky as even the slightest head movement can corrupt the data – this is especially problematic when studying adolescent development as younger people find it harder to keep still during the scan,” he said. “Here, we used three different approaches for removing signatures of head movement from the data, and obtained consistent results, which made us confident that our conclusions are not related to head movement, but to developmental changes in the adolescent brain.”

The study was supported by the Wellcome Trust.





Contacts and sources:
University of Cambridge
Publication: . Conservative and disruptive modes of adolescent change in human brain functional connectivity. František Váša, Rafael Romero-Garcia, Manfred G. Kitzbichler, Jakob Seidlitz, Kirstie J. Whitaker, Matilde M. Vaghi, Prantik Kundu, Ameera X. Patel, Peter Fonagy, Raymond J. Dolan, Peter B. Jones, Ian M. Goodyer, Petra E. Vértes, Edward T. Bullmore. Proceedings of the National Academy of Sciences, 2020; 201906144 DOI: 10.1073/pnas.1906144117




Meteorite Chunk Contains Unexpected Evidence of Presolar Grains



An unusual chunk in a meteorite may contain a surprising bit of space history, based on new research from Washington University in St. Louis.

Presolar grains — tiny bits of solid interstellar material formed before the sun was born — are sometimes found in primitive meteorites. But a new analysis reveals evidence of presolar grains in part of a meteorite where they are not expected to be found.

Curious Marie comes from the Allende meteorite, which fell in northern Mexico in February 1969. The white, fuzzy-looking features in this fragment of Allende are calcium-aluminum-rich inclusions — some of the first solids to condense in the solar system. 
Photo: Courtesy of The Planetary Society

“What is surprising is the fact that presolar grains are present,” said Olga Pravdivtseva, research associate professor of physics in Arts & Sciences and lead author of a new paper in Nature Astronomy. “Following our current understanding of solar system formation, presolar grains could not survive in the environment where these inclusions are formed.”

Curious Marie is a notable example of an “inclusion,” or a chunk within a meteorite, called a calcium-aluminum-rich inclusion (CAI). These objects, some of the first to have condensed in the solar nebula, help cosmochemists define the age of the solar system. This particular chunk of meteorite — from the collection of the Robert A. Pritzker Center for Meteoritics and Polar Studies at the Chicago Field Museum — was in the news once before, when scientists from the University of Chicago gave it its name to honor chemist Marie Curie.

Amari

Credit: Washington University
For the new work, Pravdivtseva and her co-authors, including Sachiko Amari, research professor of physics at Washington University, used noble gas isotopic signatures to show that presolar silicon carbide (SiC) grains are present in Curious Marie.

That’s important because presolar grains are generally thought to be too fragile to have endured the high-temperature conditions that existed near the birth of our sun.

But not all CAIs were formed in quite the same way.

“The fact that SiC is present in refractory inclusions tells us about the environment in the solar nebula at the condensation of the first solid materials,” said Pravdivtseva, who is part of Washington University’s McDonnell Center for the Space Sciences. “The fact that SiC was not completely destroyed in Curious Marie can help us to understand this environment a little bit better.

“Many refractory inclusions were melted and lost all textural evidence of their condensation. But not all.”

Like solving a mystery

Pravdivtseva and her collaborators used two mass spectrometers built in-house at Washington University to make their observations. The university has a long history of using noble gas isotopes as tracers of various nuclear processes and is home to one of the best-equipped noble gas laboratories in the world.Still, this work was uniquely challenging. 

Olga Pravdivtseva, research associate professor of physics in Arts & Sciences, uses noble gas isotopes to study the formation and evolution of the early solar system. Pravdivtseva, a member of the McDonnell Center for the Space Sciences, is pictured in her laboratory in Compton Hall. 
Olga Pravdivtseva
Photo: Whitney Curtis/Washington University


The researchers had 20 mg of Curious Marie to work with, which is a relatively large sample from a cosmochemistry perspective. They heated it up incrementally, increasing temperature and measuring the composition of four different noble gases released at each of 17 temperature steps.

“Experimentally, it is an elegant work,” Pravdivtseva said. “And then we had a puzzle of noble gas isotopic signatures to untangle. For me, it is like solving a mystery.”

Others have looked for evidence of SiC in such calcium-aluminum-rich inclusions in meteorites using noble gases before, but Pravdivtseva’s team is the first to find it.

“It was beautiful when all noble gases pointed to the same source of the anomalies — SiC,” she said.

“Not only do we see SiC in the fine-grained CAIs, we see a population of small grains that formed at special conditions,” Pravdivtseva said. “This finding forces us to revise how we see the conditions in the early solar nebula.”

Nebulae and galaxies. Elements of this image furnished by NASA.
 Image: Shutterstock

Funding: The work was supported by a grant from NASA.


Contacts and sources:
Talia Ogliore
Washington University in St. Louis
Publication: Evidence of presolar SiC in the Allende Curious Marie calcium–aluminium-rich inclusion. O. Pravdivtseva, F. L. H. Tissot, N. Dauphas, S. Ami. Nature Astronomy, 2020; DOI: 10.1038/s41550-019-1000-z





Thursday, January 30, 2020

Astronomers Witness the Dragging of Space-Time in Stellar Cosmic Dance

An international team of astrophysicists led by Australian Professor Matthew Bailes, from the ARC Centre of Excellence of Gravitational Wave Discovery (OzGrav), has found exciting new evidence for ‘frame-dragging’—how the spinning of a celestial body twists space and time—after tracking the orbit of an exotic stellar pair for almost two decades. The data, which is further evidence for Einstein’s theory of General Relativity, is published today (31 January 2020) in the prestigious journal, Science.

Artist’s depiction of ‘frame-dragging’: two spinning stars twisting space and time.

 Credit: Mark Myers, OzGrav ARC Centre of Excellence

​More than a century ago, Albert Einstein published his iconic theory of General Relativity – that the force of gravity arises from the curvature of space and time and that objects, such as the Sun and the Earth, change this geometry. Advances in instrumentation have led to a flood of recent (Nobel prize-winning) science from phenomena further afield linked to General Relativity. The discovery of gravitational waves was announced in 2016; the first image of a black hole shadow and stars orbiting the supermassive black hole at the centre of our own galaxy was published just last year.

Almost twenty years ago, a team led by Swinburne University of Technology’s Professor Bailes—director of the ARC Centre of Excellence in Gravitational Wave Discovery (OzGrav)—started observing two stars rotating around each other at astonishing speeds with the CSIRO Parkes 64-metre radio telescope. One is a white dwarf, the size of the Earth but 300,000 times its density; the other is a neutron star which, while only 20 kilometres in diameter, is about 100 billion times the density of the Earth. The system, which was discovered at Parkes, is a relativistic-wonder system that goes by the name ‘PSR J1141-6545’.

Artist's depiction of a neutron star orbiting a rapidly-spinning white dwarf. The white dwarf's spin drags the very fabric of space-time around with it, causing the orbit to tumble in space.
Credit: Mark Myers, OzGrav ARC Centre of Excellence.

Before the star blew up (becoming a neutron star), a million or so years ago, it began to swell up discarding its outer core which fell onto the white dwarf nearby. This falling debris made the white dwarf spin faster and faster, until its day was only measured in terms of minutes.

In 1918 (three years after Einstein published his Theory), Austrian mathematicians Josef Lense and Hans Thirring realised that if Einstein was right all rotating bodies should ‘drag’ the very fabric of space time around with them. In everyday life, the effect is miniscule and almost undetectable. Earlier this century, the first experimental evidence for this effect was seen in gyroscopes orbiting the Earth, whose orientation was dragged in the direction of the Earth’s spin. A rapidly spinning white dwarf, like the one in PSR J1141-6545, drags space-time 100 million times as strongly!

A pulsar in orbit around such a white dwarf presents a unique opportunity to explore Einstein’s theory in a new ultra-relativistic regime.

Lead author of the current study, Dr Vivek Venkatraman Krishnan (from Max Planck Institute for Radio Astronomy - MPIfR) was given the unenviable task of untangling all of the competing relativistic effects at play in the system as part of his PhD at Swinburne University of Technology. He noticed that unless he allowed for a gradual change in the orientation of the plane of the orbit, General Relativity made no sense.


Artist's depiction of a rapidly spinning neutron star and a white dwarf dragging the fabric of space time around its orbit.

Credit: Mark Myers, OzGrav ARC Centre of Excellence.


MPIfR’s Dr Paulo Friere realised that frame-dragging of the entire orbit could explain their tilting orbit and the team presents compelling evidence in support of this in today’s journal article—it shows that General Relativity is alive and well, exhibiting yet another of its many predictions.

The result is especially pleasing for team members Bailes, Willem van Straten (Auckland University of Tech) and Ramesh Bhat (ICRAR-Curtin) who have been trekking out to the Parkes 64m telescope since the early 2000s, patiently mapping the orbit with the ultimate aim of studying Einstein’s Universe. ‘This makes all the late nights and early mornings worthwhile’, said Bhat.

Expert commentary:

Lead author Vivek Venkatraman Krishnan, Max Planck Institute for Radio Astronomy (MPIfR):
‘At first, the stellar pair appeared to exhibit many of the classic effects that Einstein’s theory predicted. We then noticed a gradual change in the orientation of the plane of the orbit.’

‘Pulsars are cosmic clocks. Their high rotational stability means that any deviations to the expected arrival time of its pulses is probably due to the pulsar’s motion or due to the electrons and magnetic fields that the pulses encounter.’

‘Pulsar timing is a powerful technique where we use atomic clocks at radio telescopes to estimate the arrival time of the pulses from the pulsar to very high precision. The motion of the pulsar in its orbit modulates the arrival time, thereby enabling its measurement.’

Dr Paulo Freire: ‘We postulated that this might be, at least in-part, due to the so-called “frame-dragging” that all matter is subject to in the presence of a rotating body as predicted by the Austrian mathematicians Lense and Thirring in 1918.’

Professor Thomas Tauris, Aarhus University: ‘In a stellar pair, the first star to collapse is often rapidly rotating due to subsequent mass transfer from its companion. Tauris’s simulations helped quantify the magnitude of the white dwarf’s spin. In this system the entire orbit is being dragged around by the white dwarf’s spin, which is misaligned with the orbit.’

Dr Norbert Wex, Max Planck Institute for Radio Astronomy (MPIfR): ‘One of the first confirmations of frame-dragging used four gyroscopes in a satellite in orbit around the Earth, but in our system the effects are 100 million times stronger.’

Evan Keane (SKA Organisation): ‘Pulsars are super clocks in space. Super clocks in strong gravitational fields are Einstein’s dream laboratories. We have been studying one of the most unusual of these in this binary star system. Treating the periodic pulses of light from the pulsar like the ticks of a clock we can see and disentangle many gravitational effects as they change the orbital configuration, and the arrival time of the clock-tick pulses. In this case we have seen Lens-Thirring precession, a prediction of General Relativity, for the first time in any stellar system.’

From Willem van Straten (AUT):‘After ruling out a range of potential experimental errors, we started to suspect that the interaction between the white dwarf and neutron star was not as simple as had been assumed to date.’


Contacts and sources:
Matthew Bailes
OzGrav ARC Centre of Excellence

Publication: Lense–Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system V. Venkatraman Krishnan et al Science  31 Jan 2020: Vol. 367, Issue 6477, pp. 577-580 DOI: 10.1126/science.aax7007 http://dx.doi.org/10.1126/science.aax7007 






Ultrafast Camera Takes 1 Trillion Frames Per Second of Transparent Objects and Phenomena




A little over a year ago, Caltech's Lihong Wang developed the world's fastest camera, a device capable of taking 10 trillion pictures per second. It is so fast that it can even capture light traveling in slow motion.

But sometimes just being quick is not enough. Indeed, not even the fastest camera can take pictures of things it cannot see. To that end, Wang, Bren Professor of Medical Engineering and Electrical Engineering, has developed a new camera that can take up to 1 trillion pictures per second of transparent objects. A paper about the camera appears in the January 17 issue of the journal Science Advances.

A shockwave created by a laser striking water propagates in slow motion, as captured by a new ultrafast photography technology.
A blue dot on a black background spreads outward, indicating an expanding shockwave in water.
Credit: Caltech

The camera technology, which Wang calls phase-sensitive compressed ultrafast photography (pCUP), can take video not just of transparent objects but also of more ephemeral things like shockwaves and possibly even of the signals that travel through neurons.

Wang explains that his new imaging system combines the high-speed photography system he previously developed with an old technology, phase-contrast microscopy, that was designed to allow better imaging of objects that are mostly transparent such as cells, which are mostly water.

Phase-contrast microscopy, invented nearly 100 years ago by Dutch physicist Frits Zernike, works by taking advantage of the way that light waves slow down and speed up as they enter different materials. For example, if a beam of light passes through a piece of glass, it will slow down as it enters the glass and then speed up again as it exits. Those changes in speed alter the timing of the waves. With the use of some optical tricks it is possible to distinguish light that passed through the glass from light that did not, and the glass, though transparent, becomes much easier to see.

"What we've done is to adapt standard phase-contrast microscopy so that it provides very fast imaging, which allows us to image ultrafast phenomena in transparent materials," Wang says.

The fast-imaging portion of the system consists of something Wang calls lossless encoding compressed ultrafast technology (LLE-CUP). Unlike most other ultrafast video-imaging technologies that take a series of images in succession while repeating the events, the LLE-CUP system takes a single shot, capturing all the motion that occurs during the time that shot takes to complete. Since it is much quicker to take a single shot than multiple shots, LLE-CUP is capable of capturing motion, such as the movement of light itself, that is far too fast to be imaged by more typical camera technology.

In the new paper, Wang and his fellow researchers demonstrate the capabilities of pCUP by imaging the spread of a shockwave through water and of a laser pulse traveling through a piece of crystalline material.

A pulse of laser light travels through a crystal in slow motion, as captured by a new ultrafast photography technology.
A green beam travels from left to right across a black background.
Credit: Caltech

Wang says the technology, though still early in its development, may ultimately have uses in many fields, including physics, biology, or chemistry.

"As signals travel through neurons, there is a minute dilation of nerve fibers that we hope to see. If we have a network of neurons, maybe we can see their communication in real time," Wang says. In addition, he says, because temperature is known to change phase contrast, the system "may be able to image how a flame front spreads in a combustion chamber."

The paper describing pCUP is titled "Picosecond-resolution phase-sensitive imaging of transparent objects in a single shot." Co-authors include Taewoo Kim, a postdoctoral scholar in medical engineering, and Jinyang Liang and Liren Zhu, both formerly of Caltech.

Funding for the research was provided by the National Institutes of Health.





Contacts and sources:
Emily Velasco
Caltech







Neanderthal Ancestry in African Populations, Neanderthal DNA Discovered Carried by All Humans



After sequencing the Neanderthal genome, scientists discovered all present day non-African individuals carry some Neanderthal ancestry in their DNA. Now, researchers at Princeton University present evidence of Neanderthal ancestry in African populations too, and its origin provides new insights into human history.

After sequencing the Neanderthal genome, a team of Princeton researchers led by Joshua Akey discovered that all modern humans carry some Neanderthal ancestry in their DNA — including Africans, which was not previously known.
face of a neanderthal man in an outline of the African continent
Illustration by Matilda Luk

When the first Neanderthal genome was sequenced, using DNA collected from ancient bones, it was accompanied by the discovery that modern humans in Asia, Europe and America inherited approximately 2% of their DNA from Neanderthals — proving humans and Neanderthals had interbred after humans left Africa. Since that study, new methods have continued to catalogue Neanderthal ancestry in non-African populations, seeking to better understand human history and the effects of Neanderthal DNA on human health and disease. A comparable catalogue of Neanderthal ancestry in African populations, however, has remained an acknowledged blind spot for the field due to technical constraints and the assumption that Neanderthals and ancestral African populations were geographically isolated from each other.

In a paper published today in the journal Cell, a team of Princeton researchers detailed a new computational method for detecting Neanderthal ancestry in the human genome. Their method, called IBDmix, enabled them for the first time to search for Neanderthal ancestry in African populations as well as non-African ones. The project was led by Joshua Akey, a professor in Princeton’s Lewis-Sigler Institute for Integrative Genomics (LSI).

“This is the first time we can detect the actual signal of Neanderthal ancestry in Africans,” said co-first author Lu Chen, a postdoctoral research associate in LSI. “And it surprisingly showed a higher level than we previously thought,” she said.

The method the Princeton researchers developed, IBDmix, draws its name from the genetic principle “identity by descent” (IBD), in which a section of DNA in two individuals is identical because those individuals once shared a common ancestor. The length of the IBD segment depends on how long ago those individuals shared a common ancestor. For example, siblings share long IBD segments because their shared ancestor (a parent) is only one generation removed. Alternatively, fourth cousins share shorter IBD segments because their shared ancestor (a third-great grandparent) is several generations removed.

The Princeton team leveraged the principle of IBD to identify Neanderthal DNA in the human genome by distinguishing sequences that look similar to Neanderthals because we once shared a common ancestor in the very distant past (~500,000 years ago), from those that look similar because we interbred in the more recent present (~50,000 years ago). Previous methods relied on “reference populations” to aid the distinction of shared ancestry from recent interbreeding, usually African populations believed to carry little or no Neanderthal DNA. However, this reliance could bias estimates of Neanderthal ancestry depending on which reference population was used. The Princeton researchers termed IBDmix a “reference free method” because it does not use an African reference population. Instead, IBDmix uses characteristics of the Neanderthal sequence itself, like the frequency of mutations or the length of the IBD segments, to distinguish shared ancestry from recent interbreeding. The researchers were therefore able to identify Neanderthal ancestry in Africans for the first time and make new estimates of Neanderthal ancestry in non-Africans, which showed Europeans and Asians to have more equal levels than previously described.

Kelley Harris, a population geneticist at the University of Washington who was not involved in the study, noted that the new estimates of Neanderthal ancestry using IBDmix highlight the technical problem in methods reliant on reference panels. “We might have to go back and revisit a bunch of results from the published literature and evaluate whether the same technical issue has been throwing off our understanding of gene flow in other species,” she said.

In addition to identifying Neanderthal ancestry in African populations, the researchers described two revelations about the origin of the Neanderthal sequences. First, they determined that the Neanderthal ancestry in Africans was not due to an independent interbreeding event between Neanderthals and African populations. Based on features of the data, the research team concluded that migrations from ancient Europeans back into Africa introduced Neanderthal ancestry into African populations.

Second, by comparing data from simulations of human history to data from real people, the researchers determined that some of the detected Neanderthal ancestry in Africans was actually due to human DNA introduced into the Neanderthal genome. The authors emphasized that this human-to-Neanderthal gene flow involved an early dispersing group of humans out of Africa, occurring at least 100,000 years ago — before the Out-of-Africa migration responsible for modern human colonization of Europe and Asia and before the interbreeding event that introduced Neanderthal DNA into modern humans. The finding reaffirmed that hybridization between humans and closely related species was a recurrent part of our evolutionary history.

While the Princeton researchers acknowledged the limited number of African populations they were able to analyze, they hope their new method and their findings will encourage more study of Neanderthal ancestry across Africa and other populations. Regarding the overall significance of the research, Chen said: “This demonstrates the remnants of Neanderthal genomes survive in every modern human population studied to date.”

Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals,” by Lu Chen, Aaron B. Wolf, Wenqing Fu, Liming Li and Joshua M. Akey, appears in the Feb. 20 issue of Cell, with an advance online publication on Jan. 30 (Chen et al., 2020, Cell 180, 1–11, DOI: 10.1016/j.cell.2020.01.012). The research was supported by the National Institutes of Health’s National Institute of General Medical Sciences (R01 GM110068).



Contacts and sources:
Aaron Wolf
Lewis-Sigler Institute for Integrative Genomics
Princeton University

Publication: "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals," by Lu Chen, Aaron B. Wolf, Wenqing Fu, Liming Li and Joshua M. Akey, appears in the Feb. 20 issue of Cell, with an advance online publication on Jan. 30 (Chen et al., 2020, Cell 180, 1-11, DOI: 10.1016/j.cell.2020.01.012). The research was supported by the National Institutes of Health's National Institute of General Medical Sciences (R01 GM110068).





Earth’s Oldest Asteroid Strike Linked to ‘Big Thaw’



Curtin University scientists have discovered Earth’s oldest asteroid strike occurred at Yarrabubba, in outback Western Australia, and coincided with the end of a global deep freeze known as a Snowball Earth.

Zircon crystal used to date the Yarrabubba impact.

Credit: Curtin University

The research, published in the leading journal Nature Communications, used isotopic analysis of minerals to calculate the precise age of the Yarrabubba crater for the first time, putting it at 2.229 billion years old – making it 200 million years older than the next oldest impact.

Lead author Dr Timmons Erickson, from Curtin’s School of Earth and Planetary Sciences and NASA’s Johnson Space Center, together with a team including Professor Chris Kirkland, Associate Professor Nicholas Timms and Senior Research Fellow Dr Aaron Cavosie, all from Curtin’s School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were ‘shock recrystallized’ by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.

The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.

Professor Kirkland said the timing raised the possibility that the Earth’s oldest asteroid impact may have helped lift the planet out of a deep freeze.

“Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn’t well determined,” Professor Kirkland said.

“Now we know the Yarrabubba crater was made right at the end of what’s commonly referred to as the early Snowball Earth – a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions”.

Associate Professor Nicholas Timms noted the precise coincidence between the Yarrabubba impact and the disappearance of glacial deposits.

“The age of the Yarrabubba impact matches the demise of a series of ancient glaciations. After the impact, glacial deposits are absent in the rock record for 400 million years. This twist of fate suggests that the large meteorite impact may have influenced global climate,” Associate Professor Timms said.

“Numerical modelling further supports the connection between the effects of large impacts into ice and global climate change. Calculations indicated that an impact into an ice-covered continent could have sent half a trillion tons of water vapour – an important greenhouse gas – into the atmosphere. This finding raises the question whether this impact may have tipped the scales enough to end glacial conditions.”

Dr Aaron Cavosie said the Yarrabubba study may have potentially significant implications for future impact crater discoveries.

“Our findings highlight that acquiring precise ages of known craters is important – this one sat in plain sight for nearly two decades before its significance was realised. Yarrabubba is about half the age of the Earth and it raises the question of whether all older impact craters have been eroded or if they are still out there waiting to be discovered,” Dr Cavosie said.

The full research paper, ‘Precise radiometric age establishes Yarrabubba, Western Australia, as Earth’s oldest recognized meteorite impact structure,’ can be found online here.



Contacts and sources:
Lucien Wilkinson
Curtin University

Publication: Precise radiometric age establishes Yarrabubba, Western Australia, as Earth’s oldest recognised meteorite impact structure. Timmons M. Erickson, Christopher L. Kirkland, Nicholas E. Timms, Aaron J. Cavosie, Thomas M. Davison. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-019-13985-7






Sea-Level Rise Could Reshape the United States, Trigger Migration Inland


Climate change-driven sea-level rise could trigger mass migration of Americans to inland cities, finds new AI study.

Land-locked regions will be indirectly impacted by sea-level rise as coastal populations move inalnd to seek drier ground  

Credit: Prexels


When Hurricane Harvey slammed into the Texas coast in 2017, displaced residents flocked inland, trying to rebuild their lives in the disaster’s aftermath. Within decades, the same thing could happen at a much larger scale due to rising sea levels, says a new study led by USC Computer Science Assistant Professor Bistra Dilkina.

The study, published in PLOS ONE, Jan. 22, is the first to use machine learning to project migration patterns resulting from sea-level rise. The researchers found the impact of rising oceans will ripple across the country, beyond coastal areas at risk of flooding, as affected people move inland.

In the US alone, 13 million people could be forced to relocate due to rising sea levels by 2100. As a result, cities throughout the country will grapple with new populations. Effects could include more competition for jobs, increased housing prices, and more pressure on infrastructure networks.

Bistra Dilkina and Caleb Robinson analyze the map generated by their AI models

Credit: Haotian Mai.


“Sea level rise will affect every county in the US, including inland areas,” said Dilkina, the study’s corresponding author, a WiSE Gabilan Assistant Professor in computer science at USC and associate director of USC’s Center for AI for Society.

“We hope this research will empower urban planners and local decision-makers to prepare to accept populations displaced by sea-level rise. Our findings indicate that everybody should care about sea-level rise, whether they live on the coast or not. This is a global impact issue.”

According to the research team, most popular relocation choices will include land-locked cities such as Atlanta, Houston, Dallas, Denver and Las Vegas. The model also predicts suburban and rural areas in the Midwest will experience disproportionately large influx of people relative to their smaller local populations.

Predicting relocation areas

Sea-level rise is caused primarily by two factors related to global warming: added water from melting ice sheets and glaciers and the expansion of sea water as it warms. Within just a few decades, hundreds of thousands homes on the US coast will be flooded. In fact, by the end of the century, 6 feet of ocean-level rise would redraw the coastline of southern Florida, parts of North Carolina and Virginia and most of Boston and New Orleans.
Number of additional incoming migrants in the 1.8 meter sea-level rise scenario (versus a business-as-usual scenario) per country as a percentage of that county's population. 


Map credit:  Dilkina and Robinson


To predict the trajectory of sea-level rise migration, the researchers took existing projections of rising sea levels and combined this with population projections. Based on migration patterns after Hurricane Katrina and Hurricane Rita, the team trained machine learning models—a subset of artificial intelligence—to predict where people would relocate.

“We talk about rising sea levels, but the effects go much further than those directly affected on the coasts,” said Caleb Robinson, a USC visiting doctoral researcher from Georgia Tech advised by Dilkina and the study’s first author. “We wanted to look not only at who would be displaced, but also where they would go.”

As expected, the researchers found the greatest effects of sea-level rise migration will be felt by inland areas immediately adjacent to the coast, as well as urban areas in the southeast US. But their model also showed more incoming migrants to Houston and Dallas than previous studies, which flagged Austin as the top destination for climate migrants from the southeastern coast.

This result, notes the researchers, shows that population movement under climate change will not necessarily follow previously established patterns. In other words: it is not business as usual.

Sea-level rise could also reroute people relocating from unaffected areas. Counties surrounding Los Angeles, in particular, could see tens of thousands of migrants whose preferred coastal destinations are now flooded choosing alternative destinations.

The results of this study could help city planners and policymakers plan to expand critical infrastructure, from roads to medical services, to ensure the influx of people has a positive impact on local economies and social well-being.

“When migration occurs naturally, it is a great engine for economic activity and growth,” said co-author Juan Moreno Cruz, an economist and professor at the University of Waterloo.

“But when migration is forced upon people, productivity falls and human and social capital are lost as communities are broken apart. Understanding these migration decisions helps economies and policy makers prepare for what is to come and do as much as possible to make the influx of migration a positive experience that generates positive outcomes.”






Contacts and sources:
Caitlin Dawson
University of Southern California

Publication: Modeling migration patterns in the USA under sea level rise.Caleb Robinson, Bistra Dilkina, Juan Moreno-Cruz. PLOS ONE, 2020; 15 (1): e0227436

Saturday, January 11, 2020

Early Humans Revealed to Have Engineered Optimized Stone Tools at Olduvai Gorge

Early Stone Age populations living between 1.8 – 1.2 million years ago engineered their stone tools in complex ways to make optimised cutting tools, according to a new study by Kent and UCL.

The research, published in the Journal of Royal Society Interface on 8 January, shows that Palaeolithic hominins selected different raw materials for different stone tools based on information about how sharp, durable and efficient those materials were. They made these decisions in conjunction with information about the length of time the tools would be used for and the force with which they could be applied. This reveals previously unseen complexity in the design and production of stone tools during this period.
Credit: University of Kent


The research was led by Dr Alastair Key, from the School of Anthropology and Conservation, and is based on evidence from mechanical testing of the raw materials and artefacts found at Olduvai Gorge in Tanzania – one of the world’s most important sites for human origins research.

Dr Key collaborated with Dr Tomos Proffitt from UCL Institute of Archaeology and Professor Ignacio de la Torre of the CSIC-Centro de Ciencias Humanas y Sociales in Madrid, for the study.

Their research, which employed experimental methods more commonly used in modern engineering research, shows that hominins preferentially selected quartzite, the sharpest but least durable stone type at Olduvai for flake tools; a technology thought to have been used for expedient, short-lived cutting activities.

Chert, which was identified as being highly durable and nearly as sharp as quartzite, was only available to hominins for a short 200,000 year period. Whenever it was available chert was favoured for a variety of stone tool types due to its ability to maximise cutting performance over extended tool-use durations.

Other stone types, including highly durable lavas, were available at Olduvai, however their use varied according to factors such as how long a tool was intended to be used for, a tool’s potential to create high cutting forces, and the distance hominins had to travel to raw material sources.

Olduvai Gorge
Credit: University of Kent

The study reveals a level of complexity and flexibility in stone tool production previously unseen at this time. Earlier research had demonstrated Early Stone Age populations in Kenya to select highly durable stone types for tools, but this is the first time cutting edge sharpness has been able to be considered. By selecting the material best suited to specific functional needs, hominins optimised the performance of their tools and ensured a tool’s efficiency and ‘ease-of-use’ was maximised.

Dr Key, Lecturer in Biological Anthropology, said: ‘Why Olduvai populations preferentially chose one raw material over another has puzzled archaeologists for more than 60 years. This has been made all the more intriguing given that some stone types, including lavas and quartzite, were always available.

‘What we’ve been able to demonstrate is that our ancestors were making quite complex decisions about which raw materials to use, and were doing so in a way that produced tools optimised for specific circumstances. Although we knew that later hominin species, including our own, were capable of such decisions, it’s amazing to think that populations 1.8 – 1.2 million years ago were also doing so.’

Dr Proffitt added: ‘Early hominins during the Oldowan were probably using stone flakes for a variety of tasks. Mostly for butchering animals whilst scavenging, but also probably for cutting various plants and possibly even shaping wood. A durable cutting edge would have been an important factor when using these tools.

‘There are many modern analytical techniques used in material sciences and engineering that can be used to interrogate the archaeological record, and may provide new insights into the mechanical properties of such tools and artefacts. By understanding the way that these tools work and their functional limits it allows archaeologists to build up a greater understanding of the capabilities of our earliest ancestors at the dawn of technology.’

The team now hopes that researchers at other archaeological sites will want to apply similar mechanical tests and techniques to help understand the behaviour of Stone Age populations.



Contacts and sources:
Gary Hughes
University of Kent

Global Warming 14 Million Years Ago Saw Temperatures Similar to 2100 Projections

Cardiff University scientists have shed new light on the Earth’s climate behaviour during the last known period of global warming over 14 million years ago.

During this period, known as the middle Miocene Climate Optimum, global temperatures were as much as 3 to 4 degrees warmer than today’s average temperatures, similar to estimates for 2100. The position of the continents were similar to today and the seas were flourishing with life.

Marine microfossil, foraminifera
Image of marine microfossil called foraminifera
Credit: Cardiff University


This period, which occurred between 15 and 17 million years ago, has puzzled geologists for decades as they have tried to explain the initial cause of the global warming and the environmental conditions that existed on Earth afterwards.

It is already known that this period of global warming was accompanied by massive volcanic eruptions which covered most of the modern-day Pacific Northwest in the USA, called the Columbia River flood basalts.

Around the same time a significant oil-rich layer of rock, known as the Monterey Formation, was created along the coastline of California as a result of the burial of carbon-rich marine life.

Up until now scientists have struggled to piece together the puzzle and come up with a viable explanation for the origin of the warmth and the link between the volcanic eruptions and the increased amounts of carbon burial.

Prof Carrie Lear, the senior scientist on the study and based at Cardiff University’s School of Earth and Ocean Sciences, said: “Our planet has been warm before. We can use ancient fossils to help understand how the climate system works during these times.”

In their study, published today in the journal Nature Communications, the team used the chemistry of marine fossils taken from long sediment cores from the Pacific, Atlantic and Indian oceans to fingerprint the temperature and carbon levels of the seawater in which the ancient creatures once lived during the middle Miocene Climate Optimum.

Their results showed that the massive volcanic eruptions of the Columbia River flood basalts released CO2 into the atmosphere and triggered a decline in ocean pH. With global temperatures rising as a consequence of this, sea-levels also rose, flooding large areas of the continents. This created the ideal conditions to bury large amounts of carbon from the accumulations of marine organisms in sediments, and to transfer volcanic carbon from the atmosphere to the ocean over tens of thousands of years.

“The elevated marine productivity and carbon burial helped to remove some of the carbon dioxide from the volcanoes and acted as a negative feedback, mitigating some, but not all, of the climatic effects associated with the outpouring of volcanic CO2,” said lead author of the study Dr Sindia Sosdian from Cardiff University’s School of Earth and Ocean Sciences.

Past large episodes of volcanism throughout Earth’s history have been linked to mass extinctions and widespread oxygen depletion in the oceans; however, there was no such occurrence in the middle Miocene Climate Optimum.

Co-author of the study Dr Tali Babila from the School of Ocean and Earth Sciences at the Univesity of Southampton added: “During the Miocene Climatic Optimum the response of the oceans and climate was remarkably similar to other massive volcanic eruptions in the geological record. The presence of the Antarctic ice sheet and the relatively slow release of carbon however minimised the magnitude of environmental change and the associated consequences on marine life during this event.”

“Thanks to our findings we now have a very clear picture of what was going on over 14 million years ago and this will change the way that scientists look at this period of global warming,” continued Dr Sosdian.

“We know that our current climate is warming much faster than the Miocene Climatic Optimum so we won’t be able to rely on these slow natural feedbacks to counteract global warming. But this research is still important because it helps us understand how our planet works when it is in a warm mode.”

This collaborative study involves Cardiff University (UK), the University of Southampton (UK), and St. Andrews University (UK) and is part of an research project funded by the National Environmental Research Council (NERC).



Contacts and sources:
Dr Sindia Sosdian, Professor Carrie Lear
Cardiff University






Friday, January 10, 2020

Study Finds Salt Nanoparticles Are Toxic to Cancer Cells



A new study at the University of Georgia has found a way to attack cancer cells that is potentially less harmful to the patient. Sodium chloride nanoparticles – more commonly known as salt – are toxic to cancer cells and offer the potential for therapies that have fewer negative side effects than current treatments.

Led by Jin Xie, associate professor of chemistry, the study found that SCNPs can be used as a Trojan horse to deliver ions into cells and disrupt their internal environment, leading to cell death. SCNPs become salt when they degrade, so they’re not harmful to the body.

Jin Xie discusses research projects with students in the laboratory.

Photo by Dorothy Kozlowski/UGA

“This technology is well suited for localized destruction of cancer cells,” said Xie, a faculty member in the Franklin College of Arts and Sciences. “We expect it to find wide applications in treatment of bladder, prostate, liver, and head and neck cancer.”

Nanoparticles are the key to delivering SCNPs into cells, according to Xie and the team of researchers. Cell membranes maintain a gradient that keeps relatively low sodium concentrations inside cells and relatively high sodium concentrations outside cells. The plasma membrane prevents sodium from entering a cell, but SCNPs are able to pass through because the cell doesn’t recognize them as sodium ions.

Once inside a cell, SCNPs dissolve into millions of sodium and chloride ions that are trapped inside by the gradient and overwhelm protective mechanisms, inducing rupture of the plasma membrane and cell death. When the plasma membrane ruptures, the molecules that leak out signal the immune system that there’s tissue damage, inducing an inflammatory response that helps the body fight pathogens.

“This mechanism is actually more toxic to cancer cells than normal cells, because cancer cells have relatively high sodium concentrations to start with,” Xie said.

Using a mouse model, Xie and the team tested SCNPs as a potential cancer therapeutic, injecting SCNPs into tumors. They found that SCNP treatment suppressed tumor growth by 66% compared to the control group, with no drop in body weight and no sign of toxicity to major organs.

They also performed a vaccination study, inoculating mice with cancer cells that had been killed via SCNPs or freeze thaw. These mice showed much greater resistance to a subsequent live cancer cell challenge, with all animals remaining tumor free for more than two weeks.

The researchers also explored anti-cancer immunity in a tumor model. After injecting primary tumors with SCNPs and leaving secondary tumors untreated, they found that the secondary tumors grew at a much lower speed than the control, showing a tumor inhibition rate of 53%.

Collectively, the results suggest that SCNPs killed cancer cells and converted the dying cancer cells to an in situ vaccine.

SCNPs are unique in the world of inorganic particles because they are made of a benign material, and their toxicity is based on the nanoparticle form, according to Xie.

“With a relatively short half-life in aqueous solutions, SCNPs are best suited for localized rather than systemic therapy. The treatment will cause immediate and immunogenic cancer cell death,” he said. “After the treatment, the nanoparticles are reduced to salts, which are merged with the body’s fluid system and cause no systematic or accumulative toxicity. No sign of systematic toxicity was observed with SCNPs injected at high doses.”

The study was published in Advanced Materials.



Contacts and sources:
Allyson MannUniversity of Georgia


Publication:
NaCl Nanoparticles as a Cancer Therapeutic. Wen Jiang, Lei Yin, Hongmin Chen, Amy Victoria Paschall, Liuyang Zhang ,Wenyan Fu, Weizhong Zhang, Trever Todd, Kevin Shengyang Yu, Shiyi  Zhou, Zipeng Zhen, Michael Butler, Li Yao, Feng Zhang, Ye Shen, Zibo Li, Amelia Yin, Hang Yin, Xianqiao Wang, Fikri Y. Avci, Xiaozhong Yu, Jin Xie.  Advanced Materials   https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201904058





Animal Life Thriving around Fukushima Shows Study



Nearly a decade after the nuclear accident in Fukushima, Japan, researchers from the University of Georgia have found that wildlife populations are abundant in areas void of human life.

Raccoon dog


 Credit: University of Georgia

The camera study, published in the Journal of Frontiers in Ecology and the Environment, reports that over 267,000 wildlife photos recorded more than 20 species, including wild boar, Japanese hare, macaques, pheasant, fox and the raccoon dog—a relative of the fox—in various areas of the landscape.

 Credit: University of Georgia

UGA wildlife biologist James Beasley said speculation and questions have come from both the scientific community and the general public about the status of wildlife years after a nuclear accident like those in Chernobyl and Fukushima.

This recent study, in addition to the team’s research in Chernobyl, provides answers to the questions.


Badger

 Credit: University of Georgia

“Our results represent the first evidence that numerous species of wildlife are now abundant throughout the Fukushima Evacuation Zone, despite the presence of radiological contamination,” said Beasley, associate professor at the Savannah River Ecology Laboratory and the Warnell School of Forestry and Natural Resources.

Species that are often in conflict with humans, particularly wild boar, were predominantly captured on camera in human-evacuated areas or zones, according to Beasley.

“This suggests these species have increased in abundance following the evacuation of people.”

The team, which included Thomas Hinton, professor at the Institute of Environmental Radioactivity at Fukushima University, identified three zones for the research.

Wild boar


 Credit: University of Georgia

Photographic data was gathered from 106 camera sites in three zones: humans excluded due to the highest level of contamination; humans restricted due to an intermediate level of contamination; and humans inhabited, an area where people have been allowed to remain due to “background” or very low levels of radiation found in the environment.

The researchers based their designations on zones previously established by the Japanese government after the 2011 Fukushima Daiichi accident.

For 120 days, cameras captured over 46,000 images of wild boar. Over 26,000 of those images were taken in the uninhabited area, compared to approximately 13,000 in the restricted and 7,000 in the inhabited zones.

Other species seen in higher numbers in the uninhabited or restricted zones included raccoons, Japanese marten and Japanese macaque or monkeys.

Japanese serow

 Credit: University of Georgia


Anticipating questions about physiological condition of the wildlife, Hinton said their results are not an assessment of an animal’s health.

“This research makes an important contribution because it examines radiological impacts to populations of wildlife, whereas most previous studies have looked for effects to individual animals,” said Hinton.

The uninhabited zone served as the control zone for the research.

The scientists said although there is no previous data on wildlife populations in the evacuated areas, the close proximity and similar landscape of the human-inhabited zone made the area the ideal control for the study.

The team evaluated the impact of other variables: distance to road, time of activity as captured by the cameras’ date-time stamps, vegetation type and elevation.

Wild hare

 Credit: University of Georgia

“The terrain varies from mountainous to coastal habitats, and we know these habitats support different types of species. To account for these factors, we incorporated habitat and landscape attributes such as elevation into our analysis,” Beasley said.

“Based on these analyses, our results show that level of human activity, elevation and habitat type were the primary factors influencing the abundance of the species evaluated, rather than radiation levels.”

Macaque monkeys

 Credit: University of Georgia

The study’s results indicate the activity pattern of most species aligned with their well-known history or behavior patterns. Raccoons, who are nocturnal, were more active during the night, while pheasants, which are diurnal animals, were more active during the day. However, wild boar inside the uninhabited area were more active during the day than boar in human-inhabited areas, suggesting they may be modifying their behavior in the absence of humans.

One exception to these patterns was the Japanese serow, a goat-like mammal. Normally far-removed from humans, they were most frequently seen on the camera footage in rural human-inhabited upland areas. The researchers suggest this might be a behavioral adjustment to avoid the rapidly growing boar population in the evacuated zone.

The free-roaming menagerie in Fukushima also included the red fox, masked palm civet, weasel, sika deer and black bear. The full list of wildlife captured on camera and additional details on the study can be found at: esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2149

Additional authors on this study include Phillip Lyons, University of Georgia’s Savannah River Ecology Laboratory, Aiken, South Carolina, and UGA’s Warnell School of Forestry and Natural Resources, Athens, Georgia; Kei Okuda and Thomas Hinton, Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan; and Mathew Hamilton, SREL, Aiken, South Carolina.





Contacts and sources:
Vicky L. Sutton-Jackson
University of Georgia

Publication: Rewilding of Fukushima's human evacuation zone. Phillip C Lyons, Kei Okuda, Matthew T Hamilton, Thomas G Hinton, James C Beasley. Frontiers in Ecology and the Environment, 2020; DOI: 10.1002/fee.2149






Skin-Like Sensors Bring a Human Touch to Wearable Tech



University of Toronto (U of T) Engineering researchers have developed a super-stretchy, transparent and self-powering sensor that records the complex sensations of human skin.

Dubbed artificial ionic skin — or AISkin for short — the researchers believe the innovative properties of AISkin could lead to future advancements in wearable electronics, personal health care and robotics. The artificial 'skin' sensor could have a big future in wearable and stretchable electronics, with applications in wound-healing, gaming and more. 

“Since it’s hydrogel, it’s inexpensive and biocompatible — you can put it on the skin without any toxic effects. It’s also very adhesive, and it doesn’t fall off, so there are so many avenues for this material,” Professor Xinyu Liu (MIE), whose lab is focused on the emerging areas of ionic skin and soft robotics.

Super stretchy, transparent and self-powering, researchers Xinyu Liu (MIE) and Binbin Ying (MIE, pictured) believe their AISkin will lead to meaningful advancements in wearable electronics, personal health care, and robotics. 
Photo: Daria Perevezentsev

The adhesive AISkin is made of two oppositely charged sheets of stretchable substances known as hydrogels. By overlaying negative and positive ions, the researchers create what they call a “sensing junction” on the gel’s surface.

When the AISkin is subjected to strain, humidity or changes in temperature, it generates controlled ion movements across the sensing junction, which can be measured as electrical signals such as voltage or current.

“If you look at human skin, how we sense heat or pressure, our neural cells transmit information through ions — it’s really not so different from our artificial skin,” says Liu.

AISkin is also uniquely tough and stretchable. “Our human skin can stretch about 50 per cent, but our AISkin can stretch up to 400 per cent of its length without breaking,” says Binbin Ying (MIE), a visiting PhD candidate from McGill University who’s leading the project in Liu’s lab. The researchers recently published their findings in Materials Horizons.

Human skin can stretch about 50 per cent, but our AISkin can stretch up to 400 per cent of its length without breaking.
 (Video: Daria Perevezentsev)

The new AISkin could open doors to skin-like Fitbits that measure multiple body parameters, or an adhesive touchpad you can stick onto the surface of your hand, adds Liu. “It could work for athletes looking to measure the rigour of their training, or it could be a wearable touchpad to play games.”

It could also measure the progress of muscle rehabilitation. “If you were to put this material on a glove of a patient rehabilitating their hand for example, the health care workers would be able to monitor their finger-bending movements,” says Liu.

Binbin Ying demonstrates how AISkin could be used to measure the progress of muscle rehabilitation. 
(Courtesy of Binbin Ying)

Another application is in soft robotics — flexible bots made completely out of polymers. An example is soft robotic grippers used in factories to handle delicate objects such as light bulbs or food.

The researchers envision AISkin being integrated onto soft robots to measure data, whether it’s the temperature of food or the pressure necessary to handle brittle objects.

Over the next year, Liu’s lab will be focused on further enhancing their AISkin, aiming to shrink the size of AISkin sensors through microfabrication. They’ll also add bio-sensing capabilities to the material, allowing it to measure biomolecules in body fluids such as sweat.

“If we further advance this research, this could be something we put on like a ‘smart bandage,’” says Liu. “Wound healing requires breathability, moisture balance – ionic skin feels like the natural next step.”





Contacts and sources:
Liz Do
University of Toronto Engineering


Publication: An ambient-stable and stretchable ionic skin with multimodal sensation. Binbin Ying, Qiyang Wu, Jianyu Li and Xinyu Liu. Material Horizons http://dx.doi.org/10.1039/C9MH00715F






Baby and Adult Brains 'Sync Up' During Play, Finds Princeton Baby Lab

Have you ever played with a baby and felt a sense of connection, even though they couldn’t yet talk to you? New research suggests that you might quite literally be “on the same wavelength,” experiencing similar brain activity in the same brain regions.

It’s not your imagination — you and your baby really are on the same wavelength. "Infancy is the foundational period for learning from adults, and the dynamics of the social environment have long been considered central to children’s development."

A team of Princeton researchers has developed a way to measure baby and adult brain activity during natural interaction. In their experiment, an adult spent five minutes playing, singing songs and reading “Goodnight Moon” with babies and toddlers, as the researchers measured neural synchrony using a method called functional near-infrared spectroscopy.

Photo by Elise Piazza, Princeton Baby Lab

A team of Princeton researchers has conducted the first study of how baby and adult brains interact during natural play, and they found measurable similarities in their neural activity. In other words, baby and adult brain activity rose and fell together as they shared toys and eye contact. The research was conducted at the Princeton Baby Lab, where University researchers study how babies learn to see, talk and understand the world.

“Previous research has shown that adults’ brains sync up when they watch movies and listen to stories, but little is known about how this ‘neural synchrony’ develops in the first years of life,” said Elise Piazza, an associate research scholar in the Princeton Neuroscience Institute (PNI) and the first author on a paper published Dec. 17, 2019, in Psychological Science.

Piazza and her co-authors — Liat Hasenfratz, an associate research scholar in PNI; Uri Hasson, a professor of psychology and neuroscience; and Casey Lew-Williams, an associate professor of psychology — posited that neural synchrony has important implications for social development and language learning.

Studying real-life, face-to-face communication between babies and adults is quite difficult. Most past studies of neural coupling, many of which were conducted in Hasson’s lab, involved scanning adults’ brains with functional magnetic resonance imaging (fMRI), in separate sessions, while the adults lay down and watched movies or listened to stories.

But to study real-time communication, the researchers needed to create a child-friendly method of recording brain activity simultaneously from baby and adult brains. With funding from the Eric and Wendy Schmidt Transformative Technology Grant, the researchers developed a new dual-brain neuroimaging system that uses functional near-infrared spectroscopy (fNIRS), which is highly safe and records oxygenation in the blood as a proxy for neural activity. The setup allowed the researchers to record the neural coordination between babies and an adult while they played with toys, sang songs and read a book.

The same adult interacted with all 42 infants and toddlers who participated in the study. Of those, 21 had to be excluded because they “squirmed excessively,” and three others flat-out refused to wear the cap, leaving 18 children, ranging in age from 9 months to 15 months.

The experiment had two portions. In one, the adult experimenter spent five minutes interacting directly with a child — playing with toys, singing nursery rhymes or reading Goodnight Moon — while the child sat on their parent’s lap. In the other, the experimenter turned to the side and told a story to another adult while the child played quietly with their parent.

The caps collected data from 57 channels of the brain known to be involved in prediction, language processing and understanding other people’s perspectives.

When they looked at the data, the researchers found that during the face-to-face sessions, the babies’ brains were synchronized with the adult’s brain in several areas known to be involved in high-level understanding of the world — perhaps helping the children decode the overall meaning of a story or analyze the motives of the adult reading to them.

When the adult and infant were turned away from each other and engaging with other people, the coupling between them disappeared.

That fit with researchers’ expectations, but the data also had surprises in store. For example, the strongest coupling occurred in the prefrontal cortex, which is involved in learning, planning and executive functioning and was previously thought to be quite underdeveloped during infancy.

“We were also surprised to find that the infant brain was often ‘leading’ the adult brain by a few seconds, suggesting that babies do not just passively receive input but may guide adults toward the next thing they’re going to focus on: which toy to pick up, which words to say,” said Lew-Williams, who is a co-director of the Princeton Baby Lab.

“While communicating, the adult and child seem to form a feedback loop,” Piazza added. “That is, the adult’s brain seemed to predict when the infants would smile, the infants’ brains anticipated when the adult would use more ‘baby talk,’ and both brains tracked joint eye contact and joint attention to toys. So, when a baby and adult play together, their brains influence each other in dynamic ways.”

This two-brain approach to neuroscience could open doors to understanding how coupling with caregivers breaks down in atypical development — such as in children diagnosed with autism — as well as how educators can optimize their teaching approaches to accommodate children’s diverse brains.

The researchers are continuing to investigate how this neural coupling relates to preschoolers’ early language learning.

Infant and adult brains are coupled to the dynamics of natural communication,” by Elise A. Piazza, Liat Hasenfratz, Uri Hasson and Casey Lew-Williams, was published Dec. 17, 2019, in Psychological Science. This work was supported by the Princeton University C. V. Starr Fellowship to E. A. Piazza; the Eric and Wendy Schmidt Transformative Technology Award to E. A. Piazza, U. Hasson and C. Lew-Williams; National Institutes of Health Grant 5DP1HD091948 to U. Hasson; and NIH Grants R01HD095912 and R03HD079779 to C. Lew-Williams.




Contacts and sources:
Liz Fuller-Wright
Princeton University


Publication: Infant and Adult Brains Are Coupled to the Dynamics of Natural Communication Show less Elise A. Piazza, Liat Hasenfratz, Uri Hasson, Casey Lew-Williams https://journals.sagepub.com/doi/10.1177/0956797619878698 http://dx.doi.org/10.1177/0956797619878698






Giving Entire Course of Cancer Radiation Treatment in Less Than a Second is Feasible



Cancer patients may one day be able to get their entire course of radiation therapy in less than a second rather than coming in for treatment over the course of several weeks, and researchers in the Abramson Cancer Center of the University of Pennsylvania have taken the first steps toward making it a reality.  The findings related to FLASH Radiotherapy could pave a new path for the future for cancer therapy.

Radiation therapy for Hodgkin's Lymphoma in a Versa HD.
File:Radiation therapy for cancer.jpg
Credit: Jakembradford / Wikimedia Commons

In a new report published today in the International Journal of Radiation Oncology, Biology, and Physics, researchers detail how they used proton radiation to generate the dosage needed to theoretically give a cancer patient their entire course of radiotherapy in one rapid treatment. It’s known as FLASH radiotherapy, and it’s an experimental paradigm that could represent a sea change for the world of oncology in the future. In this study, researchers also found FLASH demonstrated the same effect on tumors as traditional photon radiation while sparing healthy tissue due to the shorter exposure time.

“This is the first time anyone has published findings that demonstrate the feasibility of using protons – rather than electrons – to generate FLASH doses, with an accelerator currently used for clinical treatments,” said the study’s co-senior author James M. Metz, MD, director of the Roberts Proton Therapy Center and chair of Radiation Oncology. The co-senior authors on the study are Constantinos Koumenis, PhD, the Richard H. Chamberlain Professor of Research Oncology, and Keith A. Cengel, MD, PhD, an associate professor of Radiation Oncology, both in Penn’s Perelman School of Medicine.

Metz noted that other research teams have generated similar doses using electrons, which do not penetrate deep enough into the body to be clinically useful as a cancer treatment for internal tumors. Other groups have tried the approach with conventional photons, but currently available treatment devices do not have the ability to generate the necessary dosage. This study shows, that with technical modifications, the currently available accelerators for protons can achieve FLASH doses with the biologic effects today.

The key for the Penn team was the ability to generate the dose with protons, and even in that setting, researchers had to specially develop the tools needed to effectively and accurately measure radiation doses, since the standard detectors were quickly saturated due to the high levels of radiation. The Roberts Proton Therapy Center includes a dedicated research room to run experiments like these, allowing investigators to use photon and proton radiation side-by-side just feet from the clinic. It’s one of the few facilities in the world with those unique features, and Metz said this infrastructure is what made Penn’s FLASH experiments possible.

“We’ve been able to develop specialized systems in the research room to generate FLASH doses, demonstrate that we can control the proton beam, and perform a large number of experiments to help us understand the implications of FLASH radiation that we simply could not have done with a more traditional research setup,” Metz said.

Researchers said they are already beginning to optimize how they would use this down the road for clinical trials, including taking the necessary steps to translate the ability from the research room to a clinical space, as well as designing a delivery system for FLASH in humans.

The study’s co-lead authors are Eric S. Diffenderfer, Ioannis Verginadis, and Michele Kim. Additional Penn authors include Khayrullo Shoniyozov, Anastasia Velalopoulou, Denisa Goia, Mary Putt, Sarah Hagan, Stephen Avery, Kevin Teo, Wei Zou, Alexander Lin, Samuel Swisher-McClure, Cameron Koch, Ann R. Kennedy, Andy Minn, Amit Maity, Theresa M. Busch, and Lei Dong.



Contacts and sources:
John Infanti
The Perelman School of Medicine
The University of Pennsylvania Health System


 





African Grey Parrots Spontaneously 'Lend a Wing'

People and other great apes are known for their willingness to help others in need, even strangers. "Helping others to obtain benefits, even at a cost to oneself, poses an evolutionary puzzle." say the authors of a recent study. 

Now, researchers reporting in Current Biology on January 9 have shown for the first time that some birds--and specifically African grey parrots--are similarly helpful.

"We found that African grey parrots voluntarily and spontaneously help familiar parrots to achieve a goal, without obvious immediate benefit to themselves," says study co-author Désirée Brucks of the Max Planck Institute for Ornithology, Germany.

Parrots and crows are known for having large brains relative to the size of their bodies and problem-solving skills to match. For that reason, they are sometimes considered to be "feathered apes," explain Brucks and study co-author Auguste von Bayern.

However, earlier studies showed that, despite their impressive social intelligence, crows don't help other crows. In their new study, Brucks and von Bayern wondered: what about parrots?

This image shows African grey parrots Nikki and Jack exchanging tokens with one another. 
Credit:  Anastasia Krasheninnikova

To find out, they enlisted several African grey parrots and blue-headed macaws. Both parrot species were eager to trade tokens with an experimenter for a nut treat. But, their findings show, only the African grey parrots were willing to transfer a token to a neighbor parrot, allowing the other individual to earn a nut reward.

"Remarkably, African grey parrots were intrinsically motivated to help others, even if the other individual was not their friend, so they behaved very 'prosocially,'" von Bayern says. "It surprised us that 7 out of 8 African grey parrots provided their partner with tokens spontaneously--in their very first trial--thus without having experienced the social setting of this task before and without knowing that they would be tested in the other role later on. Therefore, the parrots provided help without gaining any immediate benefits and seemingly without expecting reciprocation in return."
This image shows an overview of the test setup: the bird on the left can exchange tokens, while the exchange hole on the right is covered.

Credit: Anastasia Krasheninnikova

Importantly, she notes, the African grey parrots appeared to understand when their help was needed. When they could see the other parrot had an opportunity for exchange, they'd pass a token over. Otherwise, they wouldn't.

The parrots would help out whether the other individual was their "friend" or not, she adds. But, their relationship to the other individual did have some influence. When the parrot in need of help was a "friend," the helper transferred even more tokens.

The researchers suggest the difference between African greys and blue-headed macaws may relate to differences in their social organization in the wild. Despite those species differences, the findings show that helping behavior is not limited to humans and great apes but evolved independently also in birds.

This image shows an African grey parrot returning a token to the researcher.
Credit: Anastasia Krasheninnikova

It remains to be seen how widespread helping is across the 393 different parrot species and what factors may have led to its evolution. The researchers say that further studies are required to investigate the underlying mechanisms of the parrots' helping behavior. For instance, how do parrots tell when one of their peers needs help? And, what motivates them to respond?

Current Biology, Brucks and  von Bayern: Parrots voluntarily help each other to obtain food rewards https://www.cell.com/current-biology/fulltext/S0960-9822(19)31469-1





Contacts and sources:
Cell Press,  Current Biology

Publication: Parrots Voluntarily Help Each Other to Obtain Food Rewards. Désirée Brucks and Auguste M.P. von Bayern Published: January 09, 2020 

Thursday, January 9, 2020

Tea Drinkers Live Longer

Drinking tea at least three times a week is linked with a longer and healthier life, according to a study published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).

"Habitual tea consumption is associated with lower risks of cardiovascular disease and all-cause death," said first author Dr. Xinyan Wang, Chinese Academy of Medical Sciences, Beijing, China. "The favorable health effects are the most robust for green tea and for long-term habitual tea drinkers."

Four Green Teas in White Bowls

Credit: A Girl With Tea / Wikimedia Commons

The analysis included 100,902 participants of the China-PAR project with no history of heart attack, stroke, or cancer. Participants were classified into two groups: habitual tea drinkers (three or more times a week) and never or non-habitual tea drinkers (less than three times a week) and followed-up for a median of 7.3 years.

Habitual tea consumption was associated with more healthy years of life and longer life expectancy.

For example, the analyses estimated that 50-year-old habitual tea drinkers would develop coronary heart disease and stroke 1.41 years later and live 1.26 years longer than those who never or seldom drank tea.

Compared with never or non-habitual tea drinkers, habitual tea consumers had a 20% lower risk of incident heart disease and stroke, 22% lower risk of fatal heart disease and stroke, and 15% decreased risk of all-cause death.

Green tea 
File:Green Tea.jpg
Credit: MASA / Wikimedia Commons

The potential influence of changes in tea drinking behavior were analysed in a subset of 14,081 participants with assessments at two time points. The average duration between the two surveys was 8.2 years, and the median follow-up after the second survey was 5.3 years.

Habitual tea drinkers who maintained their habit in both surveys had a 39% lower risk of incident heart disease and stroke, 56% lower risk of fatal heart disease and stroke, and 29% decreased risk of all-cause death compared to consistent never or non-habitual tea drinkers.

Senior author Dr. Dongfeng Gu, Chinese Academy of Medical Sciences, said: "The protective effects of tea were most pronounced among the consistent habitual tea drinking group. Mechanism studies have suggested that the main bioactive compounds in tea, namely polyphenols, are not stored in the body long-term. Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect."

In a subanalysis by type of tea, drinking green tea was linked with approximately 25% lower risks for incident heart disease and stroke, fatal heart disease and stroke, and all-cause death. However, no significant associations were observed for black tea.

Dr. Gu noted that a preference for green tea is unique to East Asia. "In our study population, 49% of habitual tea drinkers consumed green tea most frequently, while only 8% preferred black tea. The small proportion of habitual black tea drinkers might make it more difficult to observe robust associations, but our findings hint at a differential effect between tea types."

Two factors may be at play. First, green tea is a rich source of polyphenols which protect against cardiovascular disease and its risk factors including high blood pressure and dyslipidaemia. Black tea is fully fermented and during this process polyphenols are oxidised into pigments and may lose their antioxidant effects. Second, black tea is often served with milk, which previous research has shown may counteract the favourable health effects of tea on vascular function.

Gender-specific analyses showed that the protective effects of habitual tea consumption were pronounced and robust across different outcomes for men, but only modest for women. Dr. Wang said: "One reason might be that 48% of men were habitual tea consumers compared to just 20% of women. Secondly, women had much lower incidence of, and mortality from, heart disease and stroke. These differences made it more likely to find statistically significant results among men."

She added: "The China-PAR project is ongoing, and with more person-years of follow-up among women the associations may become more pronounced."

The authors concluded that randomized trials are warranted to confirm the findings and provide evidence for dietary guidelines and lifestyle recommendations.

Funding: Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (2017-I2M-1-004); National Key R&D Program of China (2017YFC0211700 and 2018YFC1311703).






Contacts and sources:
The European Society of Cardiology


Publication: Tea consumption and the risk of atherosclerotic cardiovascular disease and all-cause mortality: The China-PAR project. Wang X, Liu F, Li J, et al. . Eur J Prev Cardiol. 2019. doi:10.1177/2047487319894685.
2China-PAR: Prediction for ASCVD Risk in China project