Friday, May 31, 2019

Supernovae Zapped Earth 2.6m Years Ago — Researchers Wonder If They Prompted Human Ancestors to Walk Upright



Did ancient supernovae induce proto-humans to walk on two legs, eventually resulting in homo sapiens with hands free to build cathedrals, design rockets and snap iPhone selfies?

A paper published in the Journal of Geology makes the case: Supernovae bombarded Earth with cosmic energy starting as many as 8 million years ago, with a peak some 2.6 million years ago, initiating an avalanche of electrons in the lower atmosphere and setting off a chain of events that feasibly ended with bipedal hominins such as homo habilis, dubbed “handy man.”

Supernovae bombarded Earth with cosmic energy starting as many as 8 million years ago, with a peak some 2.6 million years ago, initiating an avalanche of electrons in the lower atmosphere and setting off a chain of events that feasibly ended with bipedal hominins such as homo habilis, dubbed “handy man.” 
Credit: NASA.


The authors believe atmospheric ionization probably triggered an enormous upsurge in cloud-to-ground lightning strikes that ignited forest fires around the globe. These infernos could be one reason ancestors of homo sapiens developed bipedalism — to adapt in savannas that replaced torched forests in northeast Africa.

“It is thought there was already some tendency for hominins to walk on two legs, even before this event,” said lead author Adrian Melott, professor emeritus of physics & astronomy at the University of Kansas. “But they were mainly adapted for climbing around in trees. After this conversion to savanna, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright. They could see over the tops of grass and watch for predators. It’s thought this conversion to savanna contributed to bipedalism as it became more and more dominant in human ancestors.”

Based on a “telltale” layer of iron-60 deposits lining the world’s sea beds, astronomers have high confidence supernovae exploded in Earth’s immediate cosmic neighborhood — between 100 and only 50 parsecs (163 light years) away — during the transition from the Pliocene Epoch to the Ice Age.

“We calculated the ionization of the atmosphere from cosmic rays which would come from a supernova about as far away as the iron-60 deposits indicate,” Melott said. “It appears that this was the closest one in a much longer series. We contend it would increase the ionization of the lower atmosphere by 50-fold. Usually, you don’t get lower-atmosphere ionization because cosmic rays don’t penetrate that far, but the more energetic ones from supernovae come right down to the surface — so there would be a lot of electrons being knocked out of the atmosphere.”

According to Melott and co-author Brian Thomas of Washburn University, ionization in the lower atmosphere meant an abundance of electrons would form more pathways for lightning strikes.

“The bottom mile or so of atmosphere gets affected in ways it normally never does,” Melott said. “When high-energy cosmic rays hit atoms and molecules in the atmosphere, they knock electrons out of them — so these electrons are running around loose instead of bound to atoms. Ordinarily, in the lightning process, there’s a buildup of voltage between clouds or the clouds and the ground — but current can’t flow because not enough electrons are around to carry it. So, it has to build up high voltage before electrons start moving. Once they’re moving, electrons knock more electrons out of more atoms, and it builds to a lightning bolt. But with this ionization, that process can get started a lot more easily, so there would be a lot more lightning bolts.”

The KU researcher said the probability that this lightning spike touched off a worldwide upsurge in wildfires is supported by the discovery of carbon deposits found in soils that correspond with the timing of the cosmic-ray bombardment.

“The observation is that there’s a lot more charcoal and soot in the world starting a few million years ago,” Melott said. “It’s all over the place, and nobody has any explanation for why it would have happened all over the world in different climate zones. This could be an explanation. That increase in fires is thought to have stimulated the transition from woodland to savanna in a lot of places — where you had forests, now you had mostly open grassland with shrubby things here and there. That’s thought to be related to human evolution in northeast Africa. Specifically, in the Great Rift Valley where you get all these hominin fossils.”

Melott said no such event is likely to occur again anytime soon. The nearest star capable of exploding into a supernova in the next million years is Betelgeuse, some 200 parsecs (652 light years) from Earth.

“Betelgeuse is too far away to have effects anywhere near this strong,” Melott said. “So, don’t worry about this. Worry about solar proton events. That’s the danger for us with our technology — a solar flare that knocks out electrical power. Just imagine months without electricity.”



Contacts and sources:
Brendan M. Lynch
University of Kansas



Citation: From Cosmic Explosions to Terrestrial Fires?
Adrian L. Melott, Brian C. Thomas. The Journal of Geology, 2019; 000 DOI: 10.1086/703418

A Rose Inspires Smart Way to Collect and Purify Water



The rose may be one of the most iconic symbols of the fragility of love in popular culture, but now the flower could hold more than just symbolic value. A new device for collecting and purifying water, developed at The University of Texas at Austin, was inspired by a rose and, while more engineered than enchanted, is a dramatic improvement on current methods. Each flower-like structure costs less than 2 cents and can produce more than half a gallon of water per hour per square meter.

Credit: Cockrell School of Engineering, The University of Texas at Austin


A team led by associate professor Donglei (Emma) Fan in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering developed a new approach to solar steaming for water production – a technique that uses energy from sunlight to separate salt and other impurities from water through evaporation.

In a paper published in the most recent issue of the journal Advanced Materials, the authors outline how an origami rose provided the inspiration for developing a new kind of solar-steaming system made from layered, black paper sheets shaped into petals. Attached to a stem-like tube that collects untreated water from any water source, the 3D rose shape makes it easier for the structure to collect and retain more liquid.

Current solar-steaming technologies are usually expensive, bulky and produce limited results. The team’s method uses inexpensive materials that are portable and lightweight. Oh, and it also looks just like a black-petaled rose in a glass jar.

Those in the know would more accurately describe it as a portable low-pressure controlled solar-steaming-collection “unisystem.” But its resemblance to a flower is no coincidence.

“We were searching for more efficient ways to apply the solar-steaming technique for water production by using black filtered paper coated with a special type of polymer, known as polypyrrole,” Fan said.

Polypyrrole is a material known for its photothermal properties, meaning it’s particularly good at converting solar light into thermal heat.

Fan and her team experimented with a number of different ways to shape the paper to see what was best for achieving optimal water retention levels. They began by placing single, round layers of the coated paper flat on the ground under direct sunlight. The single sheets showed promise as water collectors but not in sufficient amounts. After toying with a few other shapes, Fan was inspired by a book she read in high school. Although not about roses per se, “The Black Tulip” by Alexandre Dumas gave her the idea to try using a flower-like shape, and she discovered the rose to be ideal. Its structure allowed more direct sunlight to hit the photothermic material – with more internal reflections – than other floral shapes and also provided enlarged surface area for water vapor to dissipate from the material.

The device collects water through its stem-like tube – feeding it to the flower-shaped structure on top. It can also collect rain drops coming from above. Water finds its way to the petals where the polypyrrole material coating the flower turns the water into steam. Impurities naturally separate from water when condensed in this way.

“We designed the purification-collection unisystem to include a connection point for a low-pressure pump to help condense the water more effectively,” said Weigu Li, a Ph.D. candidate in Fan’s lab and lead author on the paper. “Once it is condensed, the glass jar is designed to be compact, sturdy and secure for storing clean water.”

The device removes any contamination from heavy metals and bacteria, and it removes salt from seawater, producing clean water that meets drinking standard requirements set by the World Health Organization.

“Our rational design and low-cost fabrication of 3D origami photothermal materials represents a first-of-its-kind portable low-pressure solar-steaming-collection system,” Li said. “This could inspire new paradigms of solar-steaming technologies in clean water production for individuals and homes.”

The research was funded by the National Science Foundation and the Welch Foundation.



Contacts and sources:
John Holden
University of Texas at Austin


Citation: Portable Low‐Pressure Solar Steaming‐Collection Unisystem with Polypyrrole Origamis.
Weigu Li, Zheng Li, Karina Bertelsmann, Donglei Emma Fan. Advanced Materials, 2019; 1900720 DOI: 10.1002/adma.201900720



New Light on Circadian Clocks Shows Body Parts Respond to Day and Night Independently from Brain


Body parts respond to day and night independently from brain, studies show.

The future implications of our findings are vast,” says Paolo Sassone-Corsi, senior author of one of the two studies on circadian clocks published today in the journal Cell. He directs UCI’s Center for Epigenetics and Metabolism and is a Donald Bren Professor of Biological Chemistry.
UCI research helps shed new light on circadian clocks
Credit: Penny Lee / UCI School of Medicine

Can your liver sense when you’re staring at a television screen or cellphone late at night? Apparently so, and when such activity is detected, the organ can throw your circadian rhythms out of whack, leaving you more susceptible to health problems.

That’s one of the takeaways from two new studies by University of California, Irvine scientists working in collaboration with the Institute for Research in Biomedicine in Barcelona, Spain.

The studies, published today in the journal Cell, used specially bred mice to analyze the network of internal clocks that regulate metabolism. Although researchers had suspected that the body’s various circadian clocks could operate independently from the central clock in the hypothalamus of the brain, there was previously no way to test the theory, said Paolo Sassone-Corsi, director of UCI’s Center for Epigenetics and Metabolism and senior author of one of the studies.

To overcome that obstacle, scientists figured out how to disable the entire circadian system of the mice, then jump-start individual clocks. For the experiments reported in the Cell papers, they activated clocks inside the liver or skin.

“The results were quite surprising,” said Sassone-Corsi, Donald Bren Professor of Biological Chemistry. “No one realized that the liver or skin could be so directly affected by light.”

For example, despite the shutdown of all other body clocks, including the central brain clock, the liver knew what time it was, responded to light changes as day shifted to night and maintained critical functions, such as preparing to digest food at mealtime and converting glucose to energy.

Somehow, the liver’s circadian clock was able to detect light, presumably via signals from other organs. Only when the mice were subjected to constant darkness did the liver’s clock stop functioning.

In upcoming studies, UCI and Barcelona researchers will phase in other internal clocks to see how different organs communicate with each other, Sassone-Corsi said.

“The future implications of our findings are vast,” he noted. “With these mice, we can now begin deciphering the metabolic pathways that control our circadian rhythms, aging processes and general well-being.”

In earlier studies, Sassone-Corsi has examined how circadian clocks can be rewired by such factors as sleep deprivation, diet and exercise. Exposure to computer, television or cellphone light just before bed can also scramble internal clocks.

Because of modern lifestyles, it’s easy for people’s circadian systems to get confused, he said. In turn, that can lead to depression, allergies, premature aging, cancer and other health problems. Further mice experiments could uncover ways to make human internal clocks “less misaligned,” Sassone-Corsi added.

Other UCI researchers involved in the studies included Kevin B. Koronowski, Jacob G. Smith, Muntaha Samad, Siwei Chen, Christophe N. Magnan and Pierre Baldi. The work was supported by the National Institutes of Health, the Novo Nordisk Foundation, the Defense Advanced Research Projects Agency, Spain’s Ministry of Economy and Competitiveness, the European Research Council and the government of Catalonia, among other funding sources.



Contacts and sources:
Tom Vasich
University of California - Irvine

Citation: 

BMAL1-Driven Tissue Clocks Respond Independently to Light to Maintain Homeostasis.
Patrick-Simon Welz, Valentina M. Zinna, Aikaterini Symeonidi, Kevin B. Koronowski, Kenichiro Kinouchi, Jacob G. Smith, Inés Marín Guillén, Andrés Castellanos, Georgiana Crainiciuc, Neus Prats, Juan Martín Caballero, Andrés Hidalgo, Paolo Sassone-Corsi, Salvador Aznar Benitah. Cell, 2019; 177 (6): 1436 DOI: 10.1016/j.cell.2019.05.009


Defining the Independence of the Liver Circadian Clock.
Kevin B. Koronowski, Kenichiro Kinouchi, Patrick-Simon Welz, Jacob G. Smith, Valentina M. Zinna, Jiejun Shi, Muntaha Samad, Siwei Chen, Christophe N. Magnan, Jason M. Kinchen, Wei Li, Pierre Baldi, Salvador Aznar Benitah, Paolo Sassone-Corsi. Cell, 2019; 177 (6): 1448 DOI: 10.1016/j.cell.2019.04.025

Physicists ‘Teleport’ Logic Operation Between Separated Ions



Physicists at the National Institute of Standards and Technology (NIST) have teleported a computer circuit instruction known as a quantum logic operation between two separated ions (electrically charged atoms), showcasing how quantum computer programs could carry out tasks in future large-scale quantum networks.

Quantum teleportation transfers data from one quantum system (such as an ion) to another (such as a second ion), even if the two are completely isolated from each other, like two books in the basements of separate buildings. In this real-life form of teleportation, only quantum information, not matter, is transported, as opposed to the Star Trek version of “beaming” entire human beings from, say, a spaceship to a planet.

Teleportation of quantum data has been demonstrated previously with ions and a variety of other quantum systems. But the new work is the first to teleport a complete quantum logic operation using ions, a leading candidate for the architecture of future quantum computers. The experiments are described in the May 31 issue of Science.

“We verified that our logic operation works on all input states of two quantum bits with 85 to 87% probability—far from perfect, but it is a start,” NIST physicist Dietrich Leibfried said.

A full-scale quantum computer, if one can be built, could solve certain problems that are currently intractable. NIST has contributed to global research efforts to harness quantum behavior for practical technologies, including efforts to build quantum computers.

For quantum computers to perform as hoped, they will probably need millions of quantum bits, or “qubits,” as well as ways to conduct operations between qubits distributed across large-scale machines and networks. Teleportation of logic operations is one way do that without direct quantum mechanical connections (physical connections for the exchange of classical information will still be needed).

The NIST team teleported a quantum controlled-NOT (CNOT) logic operation, or logic gate, between two beryllium ion qubits located more than 340 micrometers (millionths of a meter) apart in separate zones of an ion trap, a distance that rules out any substantial direct interaction. A CNOT operation flips the second qubit from 0 to 1, or vice versa, only if the first qubit is 1; nothing happens if the first qubit is 0. In typical quantum fashion, both qubits can be in “superpositions” in which they have values of both 1 and 0 at the same time.

The NIST teleportation process relies on entanglement, which links the quantum properties of particles even when they are separated. A “messenger” pair of entangled magnesium ions is used to transfer information between the beryllium ions. (Story continues below infographic.)


Credit: D. Leibfried, N. Hanacek/NIST

The NIST team found that its teleported CNOT process entangled the two magnesium ions—a crucial early step—with a 95% success rate, while the full logic operation succeeded 85% to 87% of the time.

“Gate teleportation allows us to perform a quantum logic gate between two ions that are spatially separated and may have never interacted before,” Leibfried said. “The trick is that they each have one ion of another entangled pair by their side, and this entanglement resource, distributed ahead of the gate, allows us to do a quantum trick that has no classical counterpart.”

“The entangled messenger pairs could be produced in a dedicated part of the computer and shipped separately to qubits that need to be connected with a logic gate but are in remote locations,” Leibfried added.

The NIST work also integrated into a single experiment, for the first time, several operations that will be essential for building large-scale quantum computers based on ions, including control of different types of ions, ion transport, and entangling operations on selected subsets of the system.

To verify that they performed a CNOT gate, the researchers prepared the first qubit in 16 different combinations of input states and then measured the outputs on the second qubit. This produced a generalized quantum “truth table” showing the process worked.

In addition to generating a truth table, the researchers checked the consistency of the data over extended run times to help identify error sources in the experimental setup. This technique is expected to be an important tool in characterizing quantum information processes in future experiments.

This work was supported by the Office of the Director of National Intelligence, the Intelligence Advanced Research Projects Activity and the Office of Naval Research.




Contacts and sources:
Laura Ost
National Institute of Standards and Technology (NIST)


Citation: Quantum gate teleportation between separated qubits in a trapped-ion processor.
Yong Wan, Daniel Kienzler, Stephen D. Erickson, Karl H. Mayer, Ting Rei Tan, Jenny J. Wu, Hilma M. Vasconcelos, Scott Glancy, Emanuel Knill, David J. Wineland, Andrew C. Wilson, Dietrich Leibfried. Science, 2019; 364 (6443): 875-878 DOI: 10.1126/science.aaw9415



Ancient DNA Tells the Story of the First Herders and Farmers in East Africa



Herders move goats through the Engaruka Basin in northern Tanzania's Rift Valley. Ancient DNA shows that this way of life spread to East Africa through multiple population movements.

Credit: Katherine Grillo

"The origins of food producers in East Africa have remained elusive because of gaps in the archaeological record," said co-first author Mary Prendergast, Ph.D., professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, Spain.

A collaborative study led by archaeologists, geneticists and museum curators is providing answers to previously unsolved questions about life in sub-Saharan Africa thousands of years ago. The results were published online in the journal Science Thursday, May 30.

Researchers from North American, European and African institutions analyzed ancient DNA from 41 human skeletons curated in the National Museums of Kenya and Tanzania, and the Livingstone Museum in Zambia.

"This study uses DNA to answer previously unresolvable questions about how people were moving and interacting," added Prendergast.

Co-first author Mary Prendergast, Ph.D., is a professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, Spain.
 
Credit: Mary Prendergast


The research provides a look at the origins and movements of early African food producers.

The first form of food production to spread through most of Africa was the herding of cattle, sheep and goats. This way of life continues to support millions of people living on the arid grasslands that cover much of sub-Saharan Africa.

"Today, East Africa is one of the most genetically, linguistically, and culturally diverse places in the world," explains Elizabeth Sawchuk, Ph.D., a bioarchaeologist at Stony Brook University and co-first author of the study. "Our findings trace the roots of this mosaic back several millennia. Distinct peoples have coexisted in the Rift Valley for a very long time."

Previous archaeological research shows that the Great Rift Valley of Kenya and Tanzania was a key site for the transition from foraging to herding. Herders of livestock first appeared in northern Kenya around 5000 years ago, associated with elaborate monumental cemeteries, and then spread south into the Rift Valley, where Pastoral Neolithic cultures developed.

The new genetic results reveal that this spread of herding into Kenya and Tanzania involved groups with ancestry derived from northeast Africa, who appeared in East Africa and mixed with local foragers there between about 4500-3500 years ago. Previously, the origins and timing of these population shifts were unclear, and some archaeologists hypothesized that domestic animals spread through exchange networks, rather than by movement of people.

After around 3500 years ago, herders and foragers became genetically isolated in East Africa, even though they continued to live side by side. Archaeologists have hypothesized substantial interaction among foraging and herding groups, but the new results reveal that there were strong and persistent social barriers that lasted long after the initial encounters.

Another major genetic shift occurred during the Iron Age around 1200 years ago, with movement into the region of additional peoples from both northeastern and western Africa. These groups contributed to ancient ancestry profiles similar to those of many East Africans today. This genetic shift parallels two major cultural changes: farming and iron-working.

The study provided insight into the history of East Africa as an independent center of evolution of lactase persistence, which enables people to digest milk into adulthood. This genetic adaptation is found in high proportions among Kenyan and Tanzanian herders today.

###






Contacts and sources:
Jeanette GriderSaint Louis University


Citation: The study was supported by funding from the Howard Hughes Medical Institute, with additional funding from the US. National Institutes of Health (5R01GM100233), Allen Discovery Center, and John Templeton Foundation, NSF Archaeometry Program, and Radcliffe Institute for Advanced Study.

Mary Prendergast, Saint Louis University; Mark Lipson, Harvard Medical School; and Elizabeth Sawchuk, Stony Brook University; are study co-first authors and David Reich, Harvard Medical School is senior author.

Other authors are: Inigo Olalde (Harvard Medical School), Christine Ogola (National Museum of Kenya), Nadin Rohland (Harvard Medical School), Kendra Sirak (Harvard Medical School), Nicole Adamski (Harvard Medical School), Rebecca Bernardos (Harvard Medical School), Nasreen Broomandkhoshbacht (Harvard Medical School), Kimberly Callan (Harvard Medical School), Brendan Culleton (Pennsylvania State University), Laurie Eccles (Pennsylvania State University), Thomas Harper (Pennsylvania State University), Ann Marie Lawson (Harvard Medical School), Matthew Mah (Harvard Medical School), Jonas Oppenheimer (Harvard Medical School), Kristin Stewardson (Harvard Medical School), Fatma Zalzala (Harvard Medical School), Stanley Ambrose (University of Illinois Urbana-Champaign), George Ayodo (Jaramogi Oginga Odinga University of Science and Technology), Henry Louis Gates Jr. (Harvard University), Agness Gidna (National Museum of Tanzania), Maggie Katongo (Livingstone Museum), Amandus Kwekason (National Museum of Tanzania), Audax Mabulla (National Museum of Tanzania), George Mudenda (Livingstone Museum), Emmanuel Ndiema (National Museum of Kenya), Charles Nelson (Western Washington University), Peter Robertshaw (California State University San Bernardino), Douglas Kennett (University of California Santa Barbara), and Fredrick Manthi (National Museum of Kenya)

Prendergast and Sawchuk published a companion piece on their work in The Conversation.



Thursday, May 30, 2019

The 'Forbidden' Planet Found in the 'Neptunian Desert'



A Neptunian planet has been found in what should be a 'Neptunian Desert' by telescopes run by the University of Warwick in an international collaboration of astronomers.

NGTS-4b is 20% smaller than Neptune, about 3 times the size of Earth, and has been nicknamed the 'Forbidden' planet by researchers

Discovered using the state-of-the-art Next-Generation Transit Survey (NGTS) observing facility, designed to search for transiting planets on bright stars, but NGTS-4b is so small other ground surveys wouldn't have spotted it.

Exoplanet NGTS-4b -- also known as 'The Forbidden Planet'
Credit: University of Warwick/Mark Garlick

It's hotter than Mercury at 1,000 degrees Celsius

An exoplanet smaller than Neptune with its own atmosphere has been discovered in the Neptunian Desert, by an international collaboration of astronomers, with the University of Warwick taking a leading role.

New research, led by Dr Richard West including Professor Peter Wheatley, Dr Daniel Bayliss and Dr James McCormac from the Astronomy and Astrophysics Group at the University of Warwick, has identified a rogue planet.

NGTS is situated at the European Southern Observatory's Paranal Observatory in the heart of the Atacama Desert, Chile. It is a collaboration between UK Universities Warwick, Leicester, Cambridge, and Queen's University Belfast, together with Observatoire de Genève, DLR Berlin and Universidad de Chile.

NGTS-4b, also nick-named 'The Forbidden Planet' by researchers, is a planet smaller than Neptune but three times the size of Earth.

It has a mass of 20 Earth masses, and a radius 20% smaller than Neptune, and is 1000 degrees Celsius. It orbits around the star in only 1.3 days - the equivalent of Earth's orbit around the sun of one year.

It is the first exoplanet of its kind to have been found in the Neptunian Desert.

The Neptunian Desert is the region close to stars where no Neptune-sized planets are found. This area receives strong irradiation from the star, meaning the planets do not retain their gaseous atmosphere as they evaporate leaving just a rocky core. However NGTS-4b still has its atmosphere of gas.

When looking for new planets astronomers look for a dip in the light of a star - this the planet orbiting it and blocking the light. Usually only dips of 1% and more are picked up by ground-based searches, but the NGTS telescopes can pick up a dip of just 0.2%

Researchers believe the planet may have moved into the Neptunian Desert recently, in the last one million years, or it was very big and the atmosphere is still evaporating.

Dr Richard West, from the Department of Physics at the University of Warwick comments:

"This planet must be tough - it is right in the zone where we expected Neptune-sized planets could not survive. It is truly remarkable that we found a transiting planet via a star dimming by less than 0.2% - this has never been done before by telescopes on the ground, and it was great to find after working on this project for a year.

"We are now scouring out data to see if we can see any more planets in the Neptune Desert - perhaps the desert is greener than was once thought."


Contacts and sources:
Alice Scott
University of Warwick


Citation: NGTS-4b: A sub-Neptune transiting in the desert Richard G West Edward Gillen Daniel Bayliss Matthew R Burleigh Laetitia Delrez Maximilian N Günther Simon T Hodgkin James A G Jackman James S Jenkins George King James McCormac Louise D Nielsen Liam Raynard Alexis M S Smith Maritza Soto Oliver Turner Peter J Wheatley Yaseen Almleaky David J Armstrong Claudia Belardi François Bouchy Joshua T Briegal Artem Burdanov Juan Cabrera Sarah L Casewell Alexander Chaushev Bruno Chazelas Paul Chote Benjamin F Cooke Szilard Csizmadia Elsa Ducrot Philipp Eigmüller Anders Erikson Emma Foxell Boris T Gänsicke Michaël Gillon Michael R Goad Emmanuël Jehin Gregory Lambert Emma S Longstaff Tom Louden Maximiliano Moyano Catriona Murray Don Pollacco Didier Queloz Heike Rauer Sandrine Sohy Samantha J Thompson Stéphane Udry Simon R Walker Christopher A Watson Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 4, July 2019, Pages 5094–5103, https://doi.org/10.1093/mnras/stz1084  https://academic.oup.com/mnras/article/486/4/5094/5475662  http://dx.doi.org/10.1093/mnras/stz1084 
 

Friday, May 24, 2019

Chimpanzees Menu Includes Tortoises

Chimpanzees found to be eating tortoises after breaking their shells on tree trunks.

An international team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig and the University of Osnabrück, Germany, have observed wild chimpanzees in the Loango National Park, Gabon, eating tortoises. They describe the first observations of this potentially cultural behavior where chimpanzees hit tortoises against tree trunks until the tortoises’ shells break open and then feed on the meat.


Chimpanzee at Loango National Park in Gabon feeding on tortoise meat.

Credit: © Erwan Theleste

"We have known for decades that chimpanzees feed on meat from a variety of animal species, but until now the consumption of reptiles has not been observed", says Tobias Deschner, a primatologist at the Max Planck Institute for Evolutionary Anthropology. "What is particularly interesting is that they use a percussive technique that they normally employ to open hard-shelled fruits to gain access to meat of an animal that is almost inaccessible for any other predator".

The researchers studied the behaviour of chimpanzees of the newly habituated Rekambo community. They observed 38 prey events by ten different chimpanzees in the dry season, a period when other preferred food such as fruits is abundant. "Sometimes, younger animals or females were unable to crack open the tortoise on their own. They then regularly handed the tortoise over to a stronger male who cracked the tortoise’s shell open and shared the meat with all other individuals present", says Simone Pika, first author of the study and a cognitive scientist at the University of Osnabrück.

Leftovers from dinner


Credit: MaxPlanckSociety


There was one exceptional case in which an adult male, who was on his own, cracked a tortoise, ate half of it up while sitting in a tree and then tucked the rest of it in a tree fork. He climbed down, built his nest in a nearby tree and came back the next morning to retrieve the leftovers and continue to feast on them for breakfast. "This indicates that chimpanzees may plan for the future", says Pika. "The ability to plan for a future need, such as for instance hunger, has so far only been shown in non-human animals in experimental and/or captive settings. Many scholars still believe that future-oriented cognition is a uniquely human ability. Our findings thus suggest that even after decades of research, we have not yet grasped the full complexity of chimpanzees’ intelligence and flexibility".

Deschner adds: "Wild chimpanzee behaviour has been studied now for more than 50 years and at more than ten long-term field sites all across tropical Africa. It is fascinating that we can still discover completely new facets of the behavioural repertoire of this species as soon as we start studying a new population".

The authors further emphasize the importance of non-human primate field observations to inform theories of hominin evolution. "As one of our closest living relatives, the study of chimpanzee behaviour is a window into our own history and evolution", says Pika. "To prevent this window from closing once and for all, we need to do whatever we can to secure the survival of these fascinating animals in their natural habitats across Africa", concludes Deschner.





Contacts and sources:
Prof. Dr. Simone Pika, Sandra Jacob
Max Planck Institute for Evolutionary Anthropology
Citation: Wild chimpanzees (Pan troglodytes troglodytes) exploit tortoises (Kinixys erosa) via percussive technology.
Simone Pika, Harmonie Klein, Sarah Bunel, Pauline Baas, Erwan Théleste, Tobias Deschner. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-43301-8



The Beer of Pharaohs and Drunken Philistines Recreated with Ancient Yeast

What kind of beer did the Pharaohs drink? In ancient times, beer was an important ingredient in people's daily diet. Great powers were attributed to beer in the ancient world, particularly for religious worship and healing properties.

Israeli scientists resurrected yeast from ancient beer jugs to recreate a 5,000-year-old brew.

The pottery used to produce beer in antiquity served as the basis for this new research. The research was led by Dr. Ronen Hazan and Dr. Michael Klutstein, microbiologists from the School of Dental Medicine at the Hebrew University of Jerusalem (HUJI). They examined the colonies of yeast that formed and settled in the pottery's nano-pores. Ultimately, they were able to resurrect this yeast to create a high-quality beer...that's approximately 5,000 years old.

Beer cruse from Tel Tzafit/Gath archaeological digs, from which Philistine beer was produced.

Credit:  Yaniv Berman/Israel Antiquities Authority.


Many cooks were invited into this'beer kitchen to isolate the yeast specimens from the ancient debris and to create a beer with it. First the scientists reached out to vintners at Kadma Winery. This winery still produces wine in clay vessels, proving that yeast may be safely removed from pottery, even if it had lain dormant in the sun for years.

The yeast was then photographed by Dr. Tziona Ben-Gedalya at Ariel University's Eastern R&D Center. Following her initial examination, the team reached out to archaeologists Dr. Yitzhak Paz from the Israel Antiquities Authority (IAI), Professor Aren Maeir at Bar Ilan University and Professors Yuval Gadot and Oded Lipschits from Tel Aviv University. These archaeologists gave them shards of pottery that had been used as beer and mead (honey wine) jugs back in ancient times--and miraculously, still had yeast specimens stuck inside. These jars date back to the reign of Egyptian Pharaoh Narmer (roughly 3000 BCE), to Aramean King Hazael (800 BCE) and to Prophet Nehemiah (400 BCE) who, according to the bible, governed Judea under Persian rule.

The researchers, with the help of HUJI student Tzemach Aouizerat, cleaned and sequenced the full genome of each yeast specimen and turned them over to Dr. Amir Szitenberg at the Dead Sea-Arava Science Center for analysis. Szitenberg found that these 5,000-year yeast cultures are similar to those used in traditional African brews, such as the Ethiopian honey wine tej, and to modern beer yeast.


L'chaim! The Israeli research team samples their ancient brew.

Credit: Yaniv Berman, Israel Antiquities Authority.


Now it was time to recreate the ancient brew. Local Israeli beer expert Itai Gutman helped the scientists make the beer and the brew was sampled by Ariel University's Dr. Elyashiv Drori, as well as by certified tasters from the International Beer Judge Certification Program (BJCP), under the direction of brewer and Biratenu owner Shmuel Nakai. The testers gave the beer a thumbs up, deeming it high-quality and safe for consumption.

Dr. Ronen Hazan, Hebrew University-Hadassah School of Dental Medicine: "The greatest wonder here is that the yeast colonies survived within the vessel for thousands of years--just waiting to be excavated and grown. This ancient yeast allowed us to create beer that lets us know what ancient Philistine and Egyptian beer tasted like. By the way, the beer isn't bad. Aside from the gimmick of drinking beer from the time of King Pharaoh, this research is extremely important to the field of experimental archaeology--a field that seeks to reconstruct the past. Our research offers new tools to examine ancient methods, and enables us to taste the flavors of the past."

Dr. Yitzchak Paz, Israel Antiquities Authority: "We are talking about a real breakthrough here. This is the first time we succeeded in producing ancient alcohol from ancient yeast. In other words, from the original substances from which alcohol was produced. This has never been done before."

Prof. Yuval Gadot, Tel Aviv University's Department of Archaeology and Ancient Near Eastern Cultures: "We dug at Ramat Rachel, the largest Persian site in the Judaean kingdom, and found a large concentration of jugs with the letters J, H, D - Yahud - written on them. In a royal site like Ramat Rachel it makes sense that alcohol would be consumed at the home of the Persian governor."

Prof. Aren Maeir, Bar-Ilan University's Department of Land of Israel Studies and Archaeology: "These findings paint a portrait that supports the biblical image of drunken Philistines."


Contacts and sources:
Tali Aronsky
Hebrew University of Jerusalem

Citation: Isolation and Characterization of Live Yeast Cells from Ancient Vessels as a Tool in Bio-Archaeology Tzemach Aouizerat, Itai Gutman, Yitzhak Paz, Aren M. Maeir, Yuval Gadot, Daniel Gelman, Amir Szitenberg, Elyashiv Drori, Ania Pinku https://mbio.asm.org/content/10/2/e00388-19 http://dx.doi.org/10.1128/mBio.00388-19



Unique Iron Age Shield Gives Insight into Prehistoric Technology



A unique bark shield, thought to have been constructed with wooden laths during the Iron Age, has provided new insight into the construction and design of prehistoric weaponry.

The unique find has given new insight into prehistoric technology

The only one of its kind ever found in Europe, the shield was found south of Leicester on the Everards Meadows site, in what is believed to have been a livestock watering hole.

Credit:  University of York

Following analysis of the construction of the shield by Michael Bamforthat the University of York, it became apparent that the shield had been carefully constructed with wooden laths to stiffen the structure, a wooden edging rim, and a woven boss to protect the wooden handle.

Although prior evidence has shown that prehistoric people used bark to make bowls and boxes, this is the first time researchers have seen the material used for a weapon of war.

Severe damage

The outside of the shield has been painted and scored in red chequerboard decoration. Radiocarbon dating has revealed that the shield was made between 395 and 255 BC.

The shield was severely damaged before being deposited in the ground, with some of the damage likely to have been caused by the pointed tips of spears. Further analysis is planned to help understand if this occurred in battle or as an act of ritual destruction.

Prehistoric technology

Michael Bamforth, from the University of York’s Department of Archaeology, said: “This truly astonishing and unparalleled artefact has given us an insight into prehistoric technology that we could never have guessed at.

“Although we know that bark has many uses, including making boxes and containers it doesn't survive well in the archaeological record. Initially we didn't think bark could be strong enough to use as a shield to defend against spears and swords and we wondered if it could be for ceremonial use.

"It was only through experimentation that we realised it could be tough enough to protect against blows from metal weapons. Although a bark shield is not as strong as one made from wood or metal, it would be much lighter allowing the user much more freedom of movement."

CT scanning

The shield was first discovered by archaeologists at the University of Leicester's Archaeoligical Services in 2015 at an Iron Age site within a farming landscape known to have been used and managed by Iron Age communities, with the Fosse Way Roman road running close by.

Many cutting-edge analytical techniques have been used to understand the construction of the object, including CT scanning and 3D printing.

Dr Rachel Crellin, Lecturer in later Prehistory at the University of Leicester, who assessed the evidence for impact damage, said: “The first time I saw the shield I was absolutely awed by it: the complex structure, the careful decorations, and the beautiful boss.

“I must admit I was initially sceptical about whether the shield would have functioned effectively, however the experimental work showed that the shield would have worked very effectively, and analysis of the surface of the object has identified evidence of use.”

Craft practices

The shield has now been conserved by York Archaeological Trust and will be deposited with the British Museum on behalf of Everards of Leicestershire, who funded and supported the project.

Dr Julia Farley, Curator of British and European Iron Age Collections at the British Museum, said: “This is an absolutely phenomenal object, one of the most marvelous, internationally important finds that I've encountered in my career.

“Bark and basketry objects were probably commonplace in ancient Britain, but they seldom survive, so to be able to study this shield is a great privilege. It holds a rich store of information about Iron Age society and craft practices.”

Contacts and sources:
Samantha Martin
University of York






Simple Test Can Tell If You're Stressed Out


Would you like to know if you are stressed out.

Stress is often called "the silent killer" because of its stealthy and mysterious effects on everything from heart disease to mental health. University of Cincinnati engineers are developing a home-testing kit that can measure stress hormones in sweat, blood, urine or saliva.

Now researchers at the University of Cincinnati have developed a new test that can easily and simply measure common stress hormones using sweat, blood, urine or saliva. Eventually, they hope to turn their ideas into a simple device that patients can use at home to monitor their health.

University of Cincinnati research assistant Shima Dalirirad holds up a test strip that can measure stress biomarkers in UC's Nanoelectronics Laboratory.

Credit: Andrew Higley/UC Creative Services

The results were published this month in the journal American Chemical Society Sensors.

“I wanted something that’s simple and easy to interpret,” said Andrew Steckl, an Ohio Eminent Scholar and professor of electrical engineering in UC’s College of Engineering and Applied Science.

“This may not give you all the information, but it tells you whether you need a professional who can take over,” Steckl said.

The breakthrough was made possible because of UC's commitment to research as described in its strategic plan called Next Lives Here.

UC researchers developed a device that uses ultraviolet light to measure stress hormones in a drop of blood, sweat, urine or saliva. These stress biomarkers are found in all of these fluids, albeit in different quantities, Steckl said.

"It measures not just one biomarker but multiple biomarkers. And it can be applied to different bodily fluids. That's what's unique," he said.

Steckl has been studying biosensors for years in his Nanoelectronics Laboratory. The latest journal article is part of a series of research papers his group has written on biosensors, including one that provides a review of methods for point-of-care diagnostics of stress biomarkers.

University of Cincinnati research assistant Shima Dalirirad examines a machine that prints test strips in UC's Nanoelectronics Laboratory.
Credit: Andrew Higley/UC Creative Services

Personal experience helping his father with a health crisis informed his research and opinion that a home test for various health concerns would be incredibly helpful.

"I had to take him quite often to the lab or doctor to have tests done to adjust his medication. I thought it would be great if he could just do the tests himself to see if he was in trouble or just imagining things," Steckl said. "This doesn't replace laboratory tests, but it could tell patients more or less where they are."

UC received grant funding for the project from the National Science Foundation and the U.S. Air Force Research Lab. Steckl said the military studies acute stress in its pilots and others who are pushing the edges of human performance.

"Pilots are placed under enormous stress during missions. The ground controller would like to know when the pilot is reaching the end of his or her ability to control the mission properly and pull them out before a catastrophic ending," Steckl said.

But the UC device has widespread applications, Steckl said. His lab is pursuing the commercial possibilities.

"You're not going to replace a full-panel laboratory blood test. That's not the intent," Steckl said. "But if you're able to do the test at home because you're not feeling well and want to know where you stand, this will tell whether your condition has changed a little or a lot."

UC graduate Prajokta Ray, the study's first author, said she was excited to work on such a pressing problem for her Ph.D. studies.

"Stress harms us in so many ways. And it sneaks up on you. You don't know how devastating a short or long duration of stress can be," Ray said. "So many physical ailments such as diabetes, high blood pressure and neurological or psychological disorders are attributed to stress the patient has gone through. That's what interested me."

Ray said taking exams always gave her stress. Understanding how stress affects you individually could be extremely valuable, she said.

"Stress has been a hot topic over the past couple years. Researchers have tried very hard to develop a test that is cheap and easy and effective and detect these hormones in low concentrations," she said. "This test has the potential to make a strong commercial device. It would be great to see the research go in that direction."

UC is at the forefront of biosensor technology. Its labs are examining continuous sweat testing and point-of-care diagnostics for everything from traumatic brain injury to lead poisoning.

Steckl, too, has been a preeminent innovator at UC. His papers have been cited more than 13,000 times, according to Google Scholar. In 2016, he used salmon sperm, a common byproduct of the fishing industry, to replace rare earth metals used in light-emitting diodes for a new kind of organic LED.

"We're device engineers at heart," Steckl said. "We don't shy away from things we don't know much about to begin with. We look for opportunities. That's a hallmark of electrical engineers. We're not smart enough not to go where we shouldn't. Sometimes that pays off!"

Contacts and sources:


Citation:




Bacteria in Fermented Food Signal the Human Immune System, Explaining Health Benefits

How fermented food help our immune system found. 

Researchers have discovered that humans and great apes possess a receptor on their cells that detects metabolites from bacteria commonly found in fermented foods and triggers movement of immune cells. Claudia Stäubert of the University of Leipzig and colleagues report these findings in a new study published 23rd May in PLOS Genetics.

Consuming lactic acid bacteria - the kind that turn milk into yogurt and cabbage into sauerkraut - can offer many health benefits, but scientists still don't understand, on a molecular level, why it is helpful to ingest these bacteria and how that affects our immune system. Now, Stäubert and her colleagues have found one way that lactic acid bacteria interact with our bodies. Initially the researchers were investigating proteins on the surface of cells called hydroxycarboxylic acid (HCA) receptors. 

Researchers found that D-phenyllactic acid is absorbed from lactic acid bacteria fermented food (e.g. Sauerkraut) and induces HCA3-dependent migration in human monocytes. Future studies need to address how HCA3 activation by lactic acid bacteria-derived metabolites modulates immune function and energy storage.

Credit: Claudia Stäubert

Most animals have only two types of this receptor but humans and great apes have three. The researchers discovered that a metabolite produced by lactic acid bacteria, D-phenyllactic acid, binds strongly to the third HCA receptor, signalling the immune system their presence. The researchers propose that the third HCA receptor arose in a common ancestor of humans and great apes, and enabled them to consume foods that are starting to decay, such as fruits picked up from the ground.

The study yields new insights into the evolutionary dynamics between microbes and their human hosts and opens new research directions for understanding the multiple positive effects of eating fermented foods. "We are convinced that this receptor very likely mediates some beneficial and anti-inflammatory effects of lactic acid bacteria in humans," stated author Claudia Stäubert. "That is why we believe it could serve as a potential drug target to treat inflammatory diseases."

Future studies may reveal the details of how D-phenyllactic acid impacts the immune system, and whether the metabolite also affects fat cells, which also carry the third HCA receptor on their surfaces.


Contacts and sources:
Claudia Stäubert
PLOS


Citation: Metabolites of lactic acid bacteria present in fermented foods are highly potent agonists of human hydroxycarboxylic acid receptor 3. Peters A, Krumbholz P, Jäger E, Heintz-Buschart A, Çakir MV, Rothemund S, et al. (2019) PLoS Genet 15(5): e1008145. https://doi.org/10.1371/journal.pgen.1008145  The article is freely available.



Exotic Matter Discovered in The Sun's Atmosphere

Solar flares are the most energetic phenomena in the solar system. A major new finding about how matter behaves in the extreme conditions of the Sun's atmosphere was announced this week by scientists from Ireland and France.

The scientists used large radio telescopes and ultraviolet cameras on a NASA spacecraft to better understand the exotic but poorly understood "fourth state of matter". Known as plasma, this matter could hold the key to developing safe, clean and efficient nuclear energy generators on Earth. The scientists published their findings in the leading international journal Nature Communications.

Most of the matter we encounter in our everyday lives comes in the form of solid, liquid or gas, but the majority of the Universe is composed of plasma - a highly unstable and electrically charged fluid. The Sun is also made up of this plasma.

A solar flare captured by NASA's Solar Dynamics Observatory in 2015. Credit NASA, SDO.

Credit: NASA/SDO

Despite being the most common form of matter in the Universe plasma remains a mystery, mainly due to its scarcity in natural conditions on Earth, which makes it difficult to study. Special laboratories on Earth recreate the extreme conditions of space for this purpose, but the Sun represents an all-natural laboratory to study how plasma behaves in conditions that are often too extreme for the manually constructed Earth-based laboratories.

Postdoctoral Researcher at Trinity College Dublin and the Dublin Institute of Advanced Studies (DIAS), Dr Eoin Carley, led the international collaboration. He said: "The solar atmosphere is a hotbed of extreme activity, with plasma temperatures in excess of 1 million degrees Celsius and particles that travel close to light-speed. The light-speed particles shine bright at radio wavelengths, so we're able to monitor exactly how plasmas behave with large radio telescopes."

"We worked closely with scientists at the Paris Observatory and performed observations of the Sun with a large radio telescope located in Nançay in central France. We combined the radio observations with ultraviolet cameras on NASA's space-based Solar Dynamics Observatory spacecraft to show that plasma on the sun can often emit radio light that pulses like a light-house. We have known about this activity for decades, but our use of space and ground-based equipment allowed us to image the radio pulses for the first time and see exactly how plasmas become unstable in the solar atmosphere."

Studying the behaviour of plasmas on the Sun allows for a comparison of how they behave on Earth, where much effort is now under way to build magnetic confinement fusion reactors. These are nuclear energy generators that are much safer, cleaner and more efficient than their fission reactor cousins that we currently use for energy today.

Professor at DIAS and collaborator on the project, Peter Gallagher, said: "Nuclear fusion is a different type of nuclear energy generation that fuses plasma atoms together, as opposed to breaking them apart like fission does. Fusion is more stable and safer, and it doesn't require highly radioactive fuel; in fact, much of the waste material from fusion is inert helium."

"The only problem is that nuclear fusion plasmas are highly unstable. As soon as the plasma starts generating energy, some natural process switches off the reaction. While this switch-off behaviour is like an inherent safety switch -- fusion reactors cannot form runaway reactions -- it also means the plasma is difficult to maintain in a stable state for energy generation. By studying how plasmas become unstable on the Sun, we can learn about how to control them on Earth."

The success of this research was made possible by the close ties between researchers at Trinity, DIAS, and their French collaborators.

Dr Nicole Vilmer, lead collaborator on the project in Paris, said: "The Paris Observatory has a long history of making radio observations of the Sun, dating back to the 1950s. By teaming up with other radio astronomy groups around Europe we are able to make groundbreaking discoveries such as this one and continue the success we have in solar radio astronomy in France. It also further strengthens scientific collaboration between France and Ireland, which I hope continues in the future."

Dr Carley previously worked at the Paris Observatory, funded by a fellowship awarded by the Irish Research Council and the European Commission. He continues to work closely with his French colleagues today, and hopes to soon study the same phenomena using both French instruments and newly built, state-of-the-art equipment in Ireland.

Dr Carley added: "The collaboration with French scientists is ongoing and we're already making progress with newly built radio telescopes in Ireland, such as the Irish Low Frequency Array (I-LOFAR). I-LOFAR can be used to uncover new plasma physics on the Sun in far greater detail than before, teaching us about how matter behaves in both plasmas on the Sun, here on Earth and throughout the Universe in general."

The work was funded by the Irish Research Council.


Contacts and sources:
Thomas DeaneTrinity College Dublin

Citation: Loss-cone instability modulation due to a magnetohydrodynamic sausage mode oscillation in the solar corona Eoin P. Carley, Laura A. Hayes, Sophie A. Murray, Diana E. Morosan, Warren Shelley, Nicole Vilmer & Peter T. Gallagher Nature Communications 10, Article number: 2276 (2019) https://www.nature.com/articles/s41467-019-10204-1 http://dx.doi.org/10.1038/s41467-019-10204-1





Geometry of an Electron Shown in an Artificial Atom


Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

An electron is trapped in a quantum dot, which is formed in a two-dimensional gas in a semiconductor wafer. However, the electron moves within the space and, with different probabilities corresponding to a wave function, remains in certain locations within its confinement (red ellipses). Using the gold gates applied electric fields, the geometry of this wave function can be changed.

Image: University of Basel, Department of Physics


The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or coupling it with other spins is a challenge on which numerous research groups worldwide are working. The stability of a single spin and the entanglement of various spins depends, among other things, on the geometry of the electrons – which previously had been impossible to determine experimentally.

Only possible in artificial atoms

Scientists in the teams headed by professors Dominik Zumbühl and Daniel Loss from the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have now developed a method by which they can spatially determine the geometry of electrons in quantum dots.

A quantum dot is a potential trap which allows to confine free electrons in an area which is about 1000 times larger than a natural atom. Because the trapped electrons behave similar to electrons bound to an atom, quantum dots are also known as “artificial atoms”.

The electron is held in the quantum dot by electric fields. However, it moves within the space and, with different probabilities corresponding to a wave function, remains in certain locations within its confinement.

Charge distribution sheds light

The scientists use spectroscopic measurements to determine the energy levels in the quantum dot and study the behavior of these levels in magnetic fields of varying strength and orientation. Based on their theoretical model, it is possible to determine the electron’s probability density and thus its wave function with a precision on the sub-nanometer scale.

“To put it simply, we can use this method to show what an electron looks like for the first time,” explains Loss.

Better understanding and optimization

The researchers, who work closely with colleagues in Japan, Slovakia and the US, thus gain a better understanding of the correlation between the geometry of electrons and the electron spin, which should be stable for as long as possible and quickly switchable for use as a qubit.

“We are able to not only map the shape and orientation of the electron, but also control the wave function according to the configuration of the applied electric fields. This gives us the opportunity to optimize control of the spins in a very targeted manner,” says Zumbühl.

The spatial orientation of the electrons also plays a role in the entanglement of several spins. Similarly to the binding of two atoms to a molecule, the wave functions of two electrons must lie on one plane for successful entanglement.

With the aid of the developed method, numerous earlier studies can be better understood and the performance of spin qubits can be further optimized in the future.



Contacts and sources:
Prof. Dr. Dominik Zumbühl
University of Basel


Citation:
Spectroscopy of quantum dot orbitals with in-plane magnetic fieldsLeon C. Camenzind, Liuqi Yu, Peter Stano, Jeramy D. Zimmerman, Arthur C. Gossard, Daniel Loss, and Dominik M. Zumbühl
Physical Review Letters (2019), doi: 10.1103/PhysRevLett.122.207701

Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot
Peter Stano, Chen-Hsuan Hsu, Leon C. Camenzind, Liuqi Yu, Dominik Zumbühl, and Daniel Loss
Physical Review B (2019), doi: 10.1103/PhysRevB.99.085308





Did Leonardo da Vinci Have ADHD?

The best explanation for Leonardo da Vinci's inability to finish his works is that the great artist may have had Attention Deficit and Hyperactivity Disorder (ADHD), King's College London Professor Marco Catani  suggests.  ADHD is a brain disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.  

Leonardo da Vinci, presumed self-portrait circa 1512
File:Leonardo da Vinci - presumed self-portrait - WGA12798.jpg
Credit: Wikimedia Commons

Leonardo da Vinci produced some of the world’s most iconic art, but historical accounts of his work practices and behavior show that he struggled to complete projects. Drawing on these accounts, Professor Catani lays out the evidence supporting his hypothesis that, as well as explaining his chronic procrastination, ADHD could have been a factor in Leonardo’s extraordinary creativity and achievements across the arts and sciences.

Professor Catani, from the Institute of Psychiatry, Psychology & Neuroscience at King’s, says: ‘While impossible to make a post-mortem diagnosis for someone who lived 500 years ago, I am confident that ADHD is the most convincing and scientifically plausible hypothesis to explain Leonardo’s difficulty in finishing his works. Historical records show Leonardo spent excessive time planning projects but lacked perseverance. ADHD could explain aspects of Leonardo’s temperament and his strange mercurial genius.’

ADHD is a behavioral disorder characterized by continuous procrastination, the inability to complete tasks, mind-wandering and a restlessness of the body and mind. While most commonly recognised in childhood, ADHD is increasingly being diagnosed among adults including university students and people with successful careers.

Leonardo’s difficulties with sticking to tasks were pervasive from childhood. Accounts from biographers and contemporaries show Leonardo was constantly on the go, often jumping from task to task. Like many of those suffering with ADHD, he slept very little and worked continuously night and day by alternating rapid cycles of short naps and time awake.

Leonardo da Vinci, possible self-portrait, c. 1513
Credit: Wikimedia Commons

Alongside reports of erratic behaviour and incomplete projects from fellow artists and patrons, including Pope Leone X, there is indirect evidence to suggest that Leonardo’s brain was organised differently compared to average. He was left-handed and likely to be both dyslexic and have a dominance for language in the right-hand side of his brain, all of which are common among people with ADHD.

Perhaps the most distinctive and yet disruptive side of Leonardo’s mind was his voracious curiosity, which both propelled his creativity and also distracted him. Professor Catani suggests ADHD can have positive effects, for example mind-wandering can fuel creativity and originality. However, while beneficial in the initial stages of the creative process, the same traits can be a hindrance when interest shifts to something else.

Design for a helicopter
Credit: Wikimedia Commons

Professor Catani, who specialises in treating neurodevelopmental conditions like autism and ADHD, says: ‘There is a prevailing misconception that ADHD is typical of misbehaving children with low intelligence, destined for a troubled life. On the contrary, most of the adults I see in my clinic report having been bright, intuitive children but develop symptoms of anxiety and depression later in life for having failed to achieve their potential.’

‘It is incredible that Leonardo considered himself as someone who had failed in life. I hope that the case of Leonardo shows that ADHD is not linked to low IQ or lack of creativity but rather the difficulty of capitalising on natural talents. I hope that Leonardo’s legacy can help us to change some of the stigma around ADHD.’

The article, published in the journal BRAIN, is available online.


Contacts and sources:
King's College London

Citation: Leonardo da Vinci: a genius driven to distraction.
Marco Catani, Paolo Mazzarello. Brain, 2019; DOI: 10.1093/brain/awz131



Soft, Social Robot Brings Coziness to Home Robotics

Soft and cuddly social robots are coming. 

A few years ago, when social robots began appearing in stores and homes, Guy Hoffman wondered why they all looked so much alike.

“I noticed a lot of them had a very similar kind of feature – white and plasticky, designed like consumer electronic devices,” said Hoffman, assistant professor and the Mills Family Faculty Fellow in the Sibley School of Mechanical and Aerospace Engineering. “Especially when these social robots were marketed to be part of our families, I thought it would be strange to all have identical family members.”

He envisioned robots built from warmer, homier materials, such as wood and wool; he also imagined robots that could be customized by their owners, so each would be unique. A friend gave him crocheted models of his robots and he thought: What if the robot itself was crocheted? So he learned to crochet.

Project "Blossom" is a robot that is soft inside and out. It is built using traditional crafts like wool and wood. We wanted to bring back warm materials to home robotics, instead of more plastics, glass, and metal. You can customize Blossom by knitting new exteriors and attaching different crafted parts to make each robot unique.

Credit: Human-Robot Collaboration and Companionship Lab

Then he watched another friend crochet part of the robot far faster than he could. “That made me think people who are not engineers could also participate in making a robot,” he said.

These ideas led Hoffman to create Blossom – a simple, expressive, inexpensive robot platform that could be made from a kit and creatively outfitted with handcrafted materials.

“We wanted to empower people to build their own robot, but without sacrificing how expressive it is,” said Hoffman, senior author of “Blossom: A Handcrafted Open-Source Robot,” published in March in the Association for Computing Machinery Transactions on Human-Robot Interaction. “Also, it’s nice to have every robot be a little bit different. If you knit your robot, every family would have their own robot that would be unique to them.”

Blossom robots can be constructed by users from handcrafted materials, making each one a little bit different
Trio of robots
Credit: Michael Suguitan

Blossom’s mechanical design – developed with Michael Suguitan, a doctoral student in Hoffman’s lab and first author of the paper – is centered on a floating “head” platform using strings and cables for movement, making its gestures more flexible and organic than those of a robot composed of rigid parts.

Blossom can be controlled by moving a smartphone using an open-source puppeteering app; the robot’s movements resemble bouncing, stretching and dancing. The cost of the parts needed to assemble a Blossom is less than $250, and researchers are currently working on a Blossom kit made entirely of cardboard, which would be even cheaper.

Partly because of its simplicity, Blossom has a variety of potential uses, Hoffman said. Human-robot interaction researchers who aren’t engineers could build their own from a kit to use in studies. Because of the ease of interacting with the robot and the hands-on experience of helping to build it, it could help teach children about robotics.

In a case study, children ages 4-8 had a chance to control and make accessories for Blossom at a science fair. Some children created accessories, such as appendages or jewelry, while others controlled the robot so the new items could be attached, illustrating how Blossom could inspire collaboration.

“The children also had additional expectation of the robot’s movement, such as making it locomote and jump. These expectations were emphasized by that fact that several children chose to make appendages such as legs and wings,” the authors wrote.

In the coming months, Blossom will be used by the Upper Grand school district in Ontario, Canada, to help teach math to fourth-graders, Hoffman said.

He said his team also has been working on an algorithm to make Blossom react to YouTube videos – performing a certain dance in response to a certain song, for instance, building on previous research showing that a robot’s response to listening to songs can influence a human’s reaction. This might be particularly useful in modeling behavior for children with autism, Hoffman said.

“It’s meant to be a flexible kit that is also very low cost. Especially if we can make it out of cardboard, you could make it very inexpensively,” he said. “Because of computation becoming so powerful, it could be a really open-ended way for people to do whatever they want with robotics.”

The work was partly supported by a grant from Google Creative Robotics.





Contacts and sources:
Melanie Lefkowitz
Cornell University


Citation: Blossom: A Handcrafted Open-Source Robot.
Michael Suguitan, Guy Hoffman. ACM Transactions on Human-Robot Interaction, 2019; 8 (1): 1 DOI: 10.1145/3310356




Complex Bacterial Ecosystem at Work on The International Space Station


A new genomic approach provides a glimpse into the diverse bacterial ecosystem on the International Space Station. Scientists at Université de Montréal and McGill University have pioneered and tested a new genomic methodology which reveals a complex bacterial ecosystem at work on the International Space Station.

NASA astronaut Peggy Whitson walks in space outside the Destiny and Harmony modules of the International Space Station.
Credit:  University of Montreal.

Their study is published today in Environmental Microbiology.

Until now, relatively little was known about the different types of microbes found on the space station. The new approach enables researchers to identify and map different species inside the ISS, which will ultimately help safeguard astronauts’ health and be key to future long-term space travel.

It will also have applications in the realms of environmental management and health care.

“The new methodology provides us spectacular snapshots of the bacterial world in space and the possibilities of applying this method to explore new microbiome environments are really exciting,” said Nicholas Brereton, a researcher at UdeM's Institut de recherche en biologie végétale.



Credit University of Montreal 

The challenge of maintaining cleanliness within space environments was first documented on the Russian MIR space station, where conditions eventually deteriorated so much that mold became widespread. On the ISS, space agencies have been trying to reduce the amount of microbial growth in the station since it was first launched in 1998

Resupply missions bring new bacteria

Strict cleaning and decontamination protocols are now in place to maintain a healthy ISS environment; in orbit, crew members regularly clean and vacuum the space station’s living and working quarters. But as resupply missions arrive carrying a range of material including food, lab equipment, live plants and animals, new bacteria species are continually being added.

Combined with existing human bacteria, and also because no windows can be opened, the build-up of bacteria inside the cramped quarters can be significant.

"Scientists have a well-documented understanding of broad bacterial families on the ISS, but now we’ve discovered a more diverse bacterial ecosystem that we ever expected," said Emmanuel Gonzalez, a metagenomic specialist at McGill. "It’s an exciting step forward in understanding the biosphere that will accompany humans into extra-terrestrial habitats."




Credit:  University of Montreal.

Although the microbial characterization method was piloted in space, its applications will be far broader, say the scientists behind the technology. Researchers can replicate this approach to address many challenges and environments, including in oceans and soils It is already being applied to human diseases and microbiomes.




Contacts and sources:
Jeff Heinrich
University of Montreal
Citation: . ANCHOR: a 16S rRNA gene amplicon pipeline for microbial analysis of multiple environmental samples.
Emmanuel Gonzalez, Frederic E. Pitre, Nicholas J. B. BreretonEnvironmental Microbiology, 2019; DOI: 10.1111/1462-2920.14632




Oldest Meteorite Collection on Earth Found in One of the Driest Places

Meteorite with thin, dark, fusion crust in the Atacama Desert.
 Photo by Jérôme Gattacceca (CEREGE).

Earth is bombarded every year by rocky debris, but the rate of incoming meteorites can change over time. Finding enough meteorites scattered on the planet’s surface can be challenging, especially if you are interested in reconstructing how frequently they land. Now, researchers have uncovered a wealth of well-preserved meteorites that allowed them to reconstruct the rate of falling meteorites over the past two million years.

“Our purpose in this work was to see how the meteorite flux to Earth changed over large timescales—millions of years, consistent with astronomical phenomena,” says Alexis Drouard, Aix-Marseille Université, lead author of the new paper in Geology.

The L6 ordinary chondrite El Médano 128, a 556 g meteorite recovered in the Atacama Desert.

Photo courtesy CCJ-CNRS, P. Groscaux.


To recover a meteorite record for millions of years, the researchers headed to the Atacama Desert. Drouard says they needed a study site that would preserve a wide range of terrestrial ages where the meteorites could persist over long time scales.

While Antarctica and hot deserts both host a large percentage of meteorites on Earth (about 64% and 30%, respectively), Drouard says, “Meteorites found in hot deserts or Antarctica are rarely older than half a million years.” He adds that meteorites naturally disappear because of weathering processes (e.g., erosion by wind), but because these locations themselves are young, the meteorites found on the surface are also young.

“The Atacama Desert in Chile, is very old ([over] 10 million years),” says Drouard. “It also hosts the densest collection of meteorites in the world.”

Meteorite recovery campaign in the Atacama Desert (Nov. 2017). 
Photo by Katherine Joy (University of Manchester


The team collected 388 meteorites and focused on 54 stony samples from the El Médano area in the Atacama Desert. Using cosmogenic age dating, they found that the mean age was 710,000 years old. In addition, 30% of the samples were older than one million years, and two samples were older than two million. All 54 meteorites were ordinary chondrites, or stony meteorites that contain grainy minerals, but spanned three different types.

“We were expecting more ‘young’ meteorites than ‘old’ ones (as the old ones are lost to weathering),” says Drouard. “But it turned out that the age distribution is perfectly explained by a constant accumulation of meteorites for millions years.” The authors note that this is the oldest meteorite collection on Earth’s surface.

Large meteorite found in the Atacama Desert. 
Photo by Jérôme Gattacceca (CEREGE).

Drouard says this terrestrial crop of meteorites in the Atacama can foster more research on studying meteorite fluxes over large time scales. “We found that the meteorite flux seems to have remained constant over this [two-million-year] period in numbers (222 meteorites larger than 10 g per squared kilometer per million year), but not in composition,” he says. Drouard adds that the team plans to expand their work, measuring more samples and narrowing in on how much time the meteorites spent in space. “This will tell us about the journey of these meteorites from their parent body to Earth’s surface.”



Contacts and sources:
Kea Giles
Geological Society of America
Citation: The meteorite flux of the past 2 m.y. recorded in the Atacama Desert
Alexis Drouard; J. Gattacceca; A. Hutzler; P. Rochette; R. Braucher; D. Bourlès; ASTER Team; M. Gounelle; A. Morbidelli; V. Debaille; M. Van Ginneken; M. Valenzuela; Y. Quesnel; R. Martinez.  https://pubs.geoscienceworld.org/gsa/geology/article/570818/the-meteorite-flux-of-the-past-2-m-y-recorded-in.




Machines Getting "Spidey Senses"



Researchers are building animal-inspired sensors into the shells of aircraft, cars, giving them "spidey senses."

Soon drones and self-driving cars may have the tingling “spidey senses” of Spider-Man?

They might actually detect and avoid objects better, says Andres Arrieta, an assistant professor of mechanical engineering at Purdue University, because they would process sensory information faster.

Illustration by Taylor Callery

Better sensing capabilities would make it possible for drones to navigate in dangerous environments and for cars to prevent accidents caused by human error. Current state-of-the-art sensor technology doesn’t process data fast enough – but nature does.

And researchers wouldn’t have to create a radioactive spider to give autonomous machines superhero sensing abilities.

Instead, Purdue researchers have built sensors inspired by spiders, bats, birds and other animals, whose actual spidey senses are nerve endings linked to special neurons called mechanoreceptors.

In nature, ‘spidey-senses’ are activated by a force associated with an approaching object. Researchers are giving autonomous machines the same ability through sensors that change shape when prompted by a predetermined level of force.

































Credit: ETH Zürich images/Hortense Le Ferrand

The nerve endings – mechanosensors – only detect and process information essential to an animal’s survival. They come in the form of hair, cilia or feathers.  Mechanosensing is ubiquitous in natural systems. From the skin ridges of our finger tips to the microscopic ion channels in cells, mechanosensors allow organisms to probe their environment and gather information needed for processing, decision making, and actuation

“There is already an explosion of data that intelligent systems can collect – and this rate is increasing faster than what conventional computing would be able to process,” said Arrieta, whose lab applies principles of nature to the design of structures, ranging from robots to aircraft wings.

“Nature doesn’t have to collect every piece of data; it filters out what it needs,” he said.

Many biological mechanosensors filter data – the information they receive from an environment – according to a threshold, such as changes in pressure or temperature.

A spider’s hairy mechanosensors, for example, are located on its legs. When a spider’s web vibrates at a frequency associated with prey or a mate, the mechanosensors detect it, generating a reflex in the spider that then reacts very quickly. The mechanosensors wouldn’t detect a lower frequency, such as that of dust on the web, because it’s unimportant to the spider’s survival.

The idea would be to integrate similar sensors straight into the shell of an autonomous machine, such as an airplane wing or the body of a car. The researchers demonstrated in a paper published in ACS Nano that engineered mechanosensors inspired by the hairs of spiders could be customized to detect predetermined forces. In real life, these forces would be associated with a certain object that an autonomous machine needs to avoid.

But the sensors they developed don’t just sense and filter at a very fast rate – they also compute, and without needing a power supply.

“There’s no distinction between hardware and software in nature; it’s all interconnected,” Arrieta said. “A sensor is meant to interpret data, as well as collect and filter it.”

In nature, once a particular level of force activates the mechanoreceptors associated with the hairy mechanosensor, these mechanoreceptors compute information by switching from one state to another.

Purdue researchers, in collaboration with Nanyang Technology University in Singapore and ETH Zürich, designed their sensors to do the same, and to use these on/off states to interpret signals. An intelligent machine would then react according to what these sensors compute.

These artificial mechanosensors are capable of sensing, filtering and computing very quickly because they are stiff, Arrieta said. The sensor material is designed to rapidly change shape when activated by an external force. Changing shape makes conductive particles within the material move closer to each other, which then allows electricity to flow through the sensor and carry a signal. This signal informs how the autonomous system should respond.

“With the help of machine learning algorithms, we could train these sensors to function autonomously with minimum energy consumption,” Arrieta said. “There are also no barriers to manufacturing these sensors to be in a variety of sizes.”

This work is financially supported by ETH Zürich and Purdue University, and aligns with Purdue's Giant Leaps celebration, acknowledging the university’s global advancements made in AI, algorithms and automation as part of Purdue’s 150th anniversary. This is one of the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.



Contacts and sources:
Kayla Wiles
Purdue University


Citation: Filtered Mechanosensing Using Snapping Composites with Embedded Mechano-Electrical Transduction.
Hortense Le Ferrand, André R. Studart, Andres F. Arrieta. ACS Nano, 2019; 13 (4): 4752 DOI: 10.1021/acsnano.9b01095




On Mars, Sands Shift to a Different Drum

In the most detailed analysis of how sands move around on Mars, a team of planetary scientists led by the University of Arizona (UA) found that processes not involved in controlling sand movement on Earth play major roles on Mars.

The retreat of Mars' polar cap of frozen carbon dioxide during the spring and summer generates winds that drive the largest movements of sand dunes observed on the red planet. 
The retreat of Mars' polar cap of frozen carbon dioxide during the spring and summer generates winds that drive the largest movements of sand dunes observed on the red planet. (Image: NASA/JPL/University of Arizona/USGS)
Credit: NASA/JPL/University of Arizona/USGS)


Wind has shaped the face of Mars for millennia, but its exact role in piling up sand dunes, carving out rocky escarpments or filling impact craters has eluded scientists until now.

In the most detailed analysis of how sands move around on Mars, a team of planetary scientists led by Matthew Chojnacki at the University of Arizona Lunar and Planetary Lab set out to uncover the conditions that govern sand movement on Mars and how they differ from those on Earth.

The results, published in the current issue of the journal Geology, reveal that processes not involved in controlling sand movement on Earth play major roles on Mars, especially large-scale features on the landscape and differences in landform surface temperature.

"Because there are large sand dunes found in distinct regions of Mars, those are good places to look for changes," said Chojnacki, associate staff scientist at the UA and lead author of the paper, "Boundary conditions controls on the high-sand-flux regions of Mars." "If you don't have sand moving around, that means the surface is just sitting there, getting bombarded by ultraviolet and gamma radiation that would destroy complex molecules and any ancient Martian biosignatures."

Compared to Earth's atmosphere, the Martian atmosphere is so thin its average pressure on the surface is a mere 0.6 percent of our planet's air pressure at sea level. Consequently, sediments on the Martian surface move more slowly than their Earthly counterparts.

The Martian dunes observed in this study ranged from 6 to 400 feet tall and were found to creep along at a fairly uniform average speed of two feet per Earth year. For comparison, some of the faster terrestrial sand dunes on Earth, such as those in North Africa, migrate at 100 feet per year.

"On Mars, there simply is not enough wind energy to move a substantial amount of material around on the surface," Chojnacki said. "It might take two years on Mars to see the same movement you'd typically see in a season on Earth."

Planetary geologists had been debating whether the sand dunes on the red planet were relics from a distant past, when the atmosphere was much thicker, or whether drifting sands still reshape the planet's face today, and if so, to what degree.

"We wanted to know: Is the movement of sand uniform across the planet, or is it enhanced in some regions over others?" Chojnacki said. "We measured the rate and volume at which dunes are moving on Mars."

The team used images taken by the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter, which has been surveying Earth's next-door neighbor since 2006. HiRISE, which stands for High Resolution Imaging Science Experiment, is led by the UA's Lunar and Planetary Laboratory and has captured about three percent of the Martian surface in stunning detail.

The researchers mapped sand volumes, dune migration rates and heights for 54 dune fields, encompassing 495 individual dunes.

"This work could not have been done without HiRISE," said Chojnacki, who is a member of the HiRISE team. "The data did not come just from the images, but was derived through our photogrammetry lab that I co-manage with Sarah Sutton. We have a small army of undergraduate students who work part time and build these digital terrain models that provide fine-scale topography."

Across Mars, the survey found active, wind-shaped beds of sand and dust in structural fossae – craters, canyons, rifts and cracks – as well as volcanic remnants, polar basins and plains surrounding craters.

In the study's most surprising finding, the researchers discovered that the largest movements of sand in terms of volume and speed are restricted to three distinct regions: Syrtis Major, a dark spot larger than Arizona that sits directly west of the vast Isidis basin; Hellespontus Montes, a mountain range about two-thirds the length of the Cascades; and North Polar Erg, a sea of sand lapping around the north polar ice cap. All three areas are set apart from other parts of Mars by conditions not known to affect terrestrial dunes: stark transitions in topography and surface temperatures.

"Those are not factors you would find in terrestrial geology," Chojnacki said. "On Earth, the factors at work are different from Mars. For example, ground water near the surface or plants growing in the area retard dune sand movement."

On a smaller scale, basins filled with bright dust were found to have higher rates of sand movement, as well.

"A bright basin reflects the sunlight and heats up the air above much more quickly than the surrounding areas, where the ground is dark," Chojnacki said, "so the air will move up the basin toward the basin rim, driving the wind, and with it, the sand."

Understanding how sand and sediment move on Mars may help scientists plan future missions to regions that cannot easily be monitored and has implications for studying ancient, potentially habitable environments.

Funded by NASA and HiRISE, the study is co-authored by Maria Banks at NASA's Goddard Space Flight Center in Greenbelt, Maryland, Lori Fenton at the Carl Sagan Center at the SETI institute in Mountain View, California, and Anna Urso at LPL.



Contacts and sources:
Daniel Stolte
University of Arizona

Citation: Boundary conditions controls on the high-sand-flux regions of Mars
Matthew Chojnacki, Maria E. Banks, Lori K. Fenton, Anna C. Urso. Geology, 2019; 47 (5): 427 DOI: 10.1130/G45793.1