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Child’s Play: Are Tibetan Hand and Foot Traces From 200,000 Years Ago the Earliest Example of Parietal Art?

Fossilized footprints, and more rarely, handprints, can be found around the world left as people went about their daily business, preserved by freak acts of geological preservation. In new research, an international team describe ancient hand and footprints made deliberately which they argue represent art.

Hand shapes are commonly found in prehistoric caves, usually the hand is used as a stencil with pigment spread around the edge of the hand. The caves at Sulawesi (Indonesia) or at El Castillo (Spain) have some fine examples and are the oldest known to date. We call this type of art parietal art, immobile art if you prefer, since you can’t take the cave wall with you when you move on, unlike an ornament.

At Quesang high on the Tibetan Plateau the team lead by Professor David Zhang (Guangzhou University) found hand and footprints preserved in travertine from a hot spring. Travertine is freshwater limestone, often used as bathroom tiles, and in this case deposited from hot waters fed by geothermal heat. The limescale that accumulates in your kettle provides an analogy for this. When soft the travertine takes an impression, but then hardens to rock.

Five handprints and five footprints appear to have been carefully placed probably by two children judging by the size of the traces. The prints were not left during normal walking and appear to have been deliberately placed. The child making the footprints was probably around 7 years old and the other, who made the handprints, slightly older, at 12 years in age.

Were the children casually playing in the mud while other members of the group took the waters at the hot spring? We do not know, but the team argues that they left a work of art. Prehistoric graffiti if you prefer.

The team dated the travertine using a radiometric method based on the decay of uranium found in the limestone. The age is surprising with the deposit dating to between ~169,000 and 226,000 years ago.  This dates from the middle Pleistocene (mid Ice Age) and provides evidence for the earliest human occupation found to date on the Tibetan Plateau. This is quite incredible when you think of the high altitude involved, Quasang has an elevation of over 4200 meters and would have been cold even during an interglacial period. The age also makes this the oldest example of parietal art in the world.

Where the children members of our own species, Homo sapiens, or members of another extinct hominin? We don’t know but potentially they may have been an enigmatic group of archaic hominins referred to as the Denisovans, given other recent skeletal finds on the Plateau.

Should we consider this as art? Well, that depends on one’s definition, but the marks were deliberately made, and have a clear composition.  Whatever these humble traces represent, they clearly evoke images of children at high elevations, enjoying a spot of creative play.

Reference: “Earliest parietal art: Hominin hand and foot traces from the middle Pleistocene of Tibet” by David D. Zhang, Matthew R. Bennett, Hai Cheng, Leibin Wang, Haiwei Zhang, Sally C. Reynolds, Shengda Zhang, Xiaoqing Wang, Teng Li, Tommy Urban, Qing Pei, Zhifeng Wu, Pu Zhang, Chunru Liu, Yafeng Wang, Cong Wang, Dongju Zhang and R. Lawrence Edwards, 10 September 2021, Science Bulletin.

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make light interact with matter – or more technically, photons with atoms.

Physicists at EPFL have found a way to get photons to interact with pairs of atoms for the first time. The breakthrough is important for the field of cavity quantum electrodynamics (QED), a cutting-edge field leading the way to quantum technologies.

There is no doubt that we are moving steadily toward an era of technologies based on quantum physics. But to get there, we first have to master the ability to make light interact with matter – or more technically, photons with atoms.

This has already been achieved to some degree, giving us the cutting-edge field of cavity quantum electrodynamics (QED), which is already used in quantum networks and quantum information processing. Nonetheless, there are still a long way to go. Current light-matter interactions are limited to individual atoms, which limits our ability to study them in the sort of complex systems involved in quantum-based technologies.

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In a paper published in Nature, researchers from the group of Jean-Philippe Brantut at EPFL’s School of Basic Sciences have found a way to get photons to ‘mix’ with pairs of atoms at ultra-low temperatures.

The researchers used what is known as a Fermi gas, a state of matter made of atoms that resembles that of electrons in materials. “In the absence of photons, the gas can be prepared in a state where atoms interact very strongly with each other, forming loosely bound pairs,” explains Brantut. “As light is sent onto the gas, some of these pairs can be turned into chemically bound molecules by absorbing with photons.”

A key concept in this new effect is that that it happens “coherently”, which means that photon can be absorbed to turn a pair of atoms into a molecule, then emitted back, then reabsorbed multiple times. “This implies the pair-photon system forms a new type of ‘particle’ – technically an excitation – which we call ‘pair-polariton’,” says Brantut. “This is made possible in our system, where photons are confined in an ‘optical cavity’ – a closed box that forces them to interact strongly with the atoms.”

The hybrid pair-polaritons take on some of the properties of photons, meaning that they can be measured with optical methods. They also take on some of the properties of the Fermi gas, like the number of atom pairs it had originally before the incoming photons.

“Some of the very intricate properties of the gas are translated onto optical properties, which can be measured in a direct way, and even without perturbing the system,” says Brantut. “A future application would be in quantum chemistry, since we demonstrate that some chemical reactions can be coherently produced using single photons.”

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Educations

A key concept in this new effect is that that it happens “coherently”, which means that photon can

Physicists at EPFL have found a way to get photons to interact with pairs of atoms for the first time. The breakthrough is important for the field of cavity quantum electrodynamics (QED), a cutting-edge field leading the way to quantum technologies.

There is no doubt that we are moving steadily toward an era of technologies based on quantum physics. But to get there, we first have to master the ability to make light interact with matter – or more technically, photons with atoms.

This has already been achieved to some degree, giving us the cutting-edge field of cavity quantum electrodynamics (QED), which is already used in quantum networks and quantum information processing. Nonetheless, there are still a long way to go. Current light-matter interactions are limited to individual atoms, which limits our ability to study them in the sort of complex systems involved in quantum-based technologies.

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In a paper published in Nature, researchers from the group of Jean-Philippe Brantut at EPFL’s School of Basic Sciences have found a way to get photons to ‘mix’ with pairs of atoms at ultra-low temperatures.

The researchers used what is known as a Fermi gas, a state of matter made of atoms that resembles that of electrons in materials. “In the absence of photons, the gas can be prepared in a state where atoms interact very strongly with each other, forming loosely bound pairs,” explains Brantut. “As light is sent onto the gas, some of these pairs can be turned into chemically bound molecules by absorbing with photons.”

A key concept in this new effect is that that it happens “coherently”, which means that photon can be absorbed to turn a pair of atoms into a molecule, then emitted back, then reabsorbed multiple times. “This implies the pair-photon system forms a new type of ‘particle’ – technically an excitation – which we call ‘pair-polariton’,” says Brantut. “This is made possible in our system, where photons are confined in an ‘optical cavity’ – a closed box that forces them to interact strongly with the atoms.”

The hybrid pair-polaritons take on some of the properties of photons, meaning that they can be measured with optical methods. They also take on some of the properties of the Fermi gas, like the number of atom pairs it had originally before the incoming photons.

“Some of the very intricate properties of the gas are translated onto optical properties, which can be measured in a direct way, and even without perturbing the system,” says Brantut. “A future application would be in quantum chemistry, since we demonstrate that some chemical reactions can be coherently produced using single photons.”

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Educations

Times Record News! North Texas schools adjust to mask-optional life

New research released Friday by the Centers for Disease Control and Prevention reinforces an old message: COVID-19 spreads less in schools where teachers and staff wear masks. Yet the study arrives as states and school districts across the country have begun scaling back or simply dropping their masking requirements for staff and students alike.

With the majority of school-age children still too young to qualify for vaccination, Friday’s research is the latest salvo in a simmering fight between public health officials and politicians — with parents lining up on both sides.

The new study comes from Georgia and compares COVID-19 infection rates across 169 K-5 schools. Some schools required teachers, staff and sometimes students to wear masks; some did not.

Schools Are Deciding What The New CDC Mask Guidelines Mean For The Classroom
THE CORONAVIRUS CRISIS
Schools Are Deciding What The New CDC Mask Guidelines Mean For The Classroom
Between Nov. 16 and Dec. 11, researchers found that infection rates were 37% lower in schools where teachers and staff members were required to wear masks. The difference between schools that did and did not require students to wear masks was not statistically significant.

This is one more study showing that masking, among other mitigation efforts, “can reduce infections and ultimately save lives,” said Dr. Sean O’Leary, a professor of pediatrics at the University of Colorado and vice chair of the Committee on Infectious Diseases for the American Academy of Pediatrics.

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O’Leary points to a previous CDC study, of schools in Florida, that also found “a strong association with student mask requirements and lower rates of infections in students.”

Like any study, Friday’s release comes with caveats. Only 12% of schools invited to share their data did so. And it’s always worth remembering: Correlation is not causation. Still, the results offer an important warning to states and school districts that are now lifting their school-based mask requirements, especially for adults: It’s safer if you don’t.

The latest, and perhaps broadest effort to change schools’ masking policies comes from Texas, where Republican Gov. Greg Abbott issued an executive order Tuesday banning all mask mandates in the state’s public schools. After June 4, the order says, “no student, teacher, parent or other staff member or visitor may be required to wear a face covering.”

No Masks Are Required At Most Texas State Facilities Anymore
THE CORONAVIRUS CRISIS
No Masks Are Required At Most Texas State Facilities Anymore
For Abbott, and many opponents of mask mandates, the move is about restoring a balance between safety and freedom. “We can continue to mitigate COVID-19 while defending Texans’ liberty to choose whether or not they mask up,” he said in announcing the order.

Zeph Capo, president of the Texas American Federation of Teachers, called the move “unconscionable” in a statement. “The governor’s new verdict takes a blanket approach to addressing what is still extremely dangerous for some Texans — a return to school unmasked.”

And Texas isn’t alone. On Thursday, Iowa’s Republican governor, Kim Reynolds, also signed a law banning schools from requiring masks. The justification is similar: “I am proud to be a governor of a state that values personal responsibility and individual liberties,” Reynolds said in a statement.

“Whether a child wears a mask in school is a decision that should be left only to a student’s parents,” South Carolina Gov. Henry McMaster said last week as he issued an executive order allowing parents to opt their children out of school-based mask requirements.

Public health experts have been quick to sound the alarm.

“All along in this pandemic, we have seen the tragic consequences when politics start to play a role in public health decisions. And to me, this kind of maneuver smells like politics — to ban the requirements that are ultimately there to save lives,” O’Leary said. “The body of evidence shows us that masks work.”

And Dr. Aaron Milstone, a professor of pediatric infectious diseases at Johns Hopkins, likens the banning of mask mandates to having a variable speed limit.

“Unfortunately, with contagious diseases the decisions I make impact someone else,” Milstone said. “It would be like saying: You can drive 55 mph if you think that’s safe for you, but if someone else thinks they can safely drive 90 mph, their choice may wind up risking your life.”

While the CDC recently scaled back its masking guidance for people who are fully vaccinated, the agency also reiterated that schools should continue to require universal masking, at least through the end of the current school year. Though one vaccine has been approved for use for 12- to 15-year-olds, those kids won’t be considered fully vaccinated for another month.

Milstone said it’s simply too early to talk about schools without masking. “Until vaccines are eligible for all children, it’s hard to abandon the practices that we know work the best to prevent the spread of COVID.”

Dr. Anthony Fauci, chief medical adviser to the White House, told CNBC this week that it is conceivable the CDC could recommend that middle and high schools be mask-free in the fall — if, that is, enough students 12 years of age and older get vaccinated.