Category: science

Chanda and his team tested the impact this paint had on the temperature of buildings covered in structural paint versus commercial paints and they found that structural paint kept surfaces 20 to 30 degrees cooler. This, Chanda said, is a massive new tool that could be used to fight rising temperatures caused by global warming while still allowing us to have a bright and colorful world. Unlike white and black cars, structural paint’s ability to reflect heat isn’t determined by how dark the color is. Blue, black or purple structural paints reflect just as much heat as bright whites or beige. This opens the door for more colorful, cooler architecture and design without having to worry about the heat.

It’s not just cleaner, Chanda said. Structural paint weighs much less than pigmented paint and doesn’t fade over time like traditional pigments. “A raisin’s worth of structural paint is enough to cover the front and back of a door,” he said. Unlike pigments which rely on layers of pigment to achieve depth of color, structural paint only requires one thin layer of particles to fully cover a surface in color. This means that structural paint could be a boon for aerospace engineers who rely on the lowest weight possible to achieve higher fuel efficiency. The possibilities for structural paint are endless and Chanda hopes that cans of structural paint will soon be available in hardware stores.

Overall, the participants regularly misremembered the letters, but in a specific way. People were generally good at remembering when a typical letter was shown, with their inaccuracy rates hovering around 10%. But they were substantially worse at remembering a mirrored letter, with inaccuracy rates up to 40% in some experiments. And, interestingly enough, their memory got worse the longer they had to wait before recalling it. When they were asked to recall what they saw a half second later, for instance, they were wrong less than 20% of the time, but when they were asked three seconds later, the rate rose as high as 30%.

According to Otten, the findings — published Wednesday in PLOS One — indicate that our memory starts being shaped almost immediately by our preconceptions. People expect to see a regular letter, and don’t get easily fooled into misremembering a mirrored letter. But when the unexpected happens, we might often still default to our missed prediction. This bias doesn’t seem to kick in instantaneously, though, since people’s short-term memory was better when they had to be especially quick on their feet. “It is only when memory becomes less reliable through the passage of a tiny bit of time, or the addition of extra visual information, that internal expectations about the world start playing a role,” Otten said.

“I am very happy that we have developed a system that I think can truly revolutionise the industry, first of all for the benefit of the chickens but also for all of us, because this is an issue that affects every person on the planet,” he said. The scientists have gene edited DNA into the Golda hens that can stop the development of any male embryos in eggs that they lay. The DNA is activated when the eggs are exposed to blue light for several hours. Female chick embryos are unaffected by the blue light and develop normally. The chicks have no additional genetic material inside them nor do the eggs they lay, according to Dr Cinnamon. “Farmers will get the same chicks they get today and consumers will get exactly the same eggs they get today,” he said. “The only minor difference in the production process is that the eggs will be exposed to blue light.”

First things first. What we often call laws of physics are really just consistent mathematical theories that seem to match some parts of nature. This is as true for Newton’s laws of motion as it is for Einstein’s theories of relativity, Schrödinger’s and Dirac’s equations in quantum physics or even string theory. So these aren’t really laws as such, but instead precise and consistent ways of describing the reality we see. This should be obvious from the fact that these laws are not static; they evolve as our empirical knowledge of the universe improves.

Here’s the thing. Despite many scientists viewing their role as uncovering these ultimate laws, I just don’t believe they exist…. I know from my 40 years of experience in working on real-life physical phenomena that the whole idea of an ultimate law based on an equation using just the building blocks and fundamental forces is unworkable and essentially a fantasy. We never know precisely which equation describes a particular laboratory situation. Instead, we always have to build models and approximations to describe each phenomenon even when we know that the equation controlling it is ultimately some form of the Schrödinger equation!
Even with quantum mechanics, space and time are variables that have to be “put in by hand,” the article argues, “when space and time should come out naturally from any ultimate law of physics. This has remained perhaps the greatest mystery in fundamental physics with no solution in sight….”

“It is difficult to imagine that a thousand years from now physicists will still use quantum mechanics as the fundamental description of nature…. I see no particular reason that our description of how the physical universe seems to work should reach the pinnacle suddenly in the beginning of the 21st century and become stuck forever at quantum mechanics. That would be a truly depressing thought…!”

“Our understanding of the physical world must continue indefinitely, unimpeded by the search for ultimate laws. Laws of physics continuously evolve — they will never be ultimate.”
Thanks to long-time Slashdot reader InfiniteZero for sharing the article!

“Physicists described the achievement as another small step in the effort to understand the relation between gravity, which shapes the universe, and quantum mechanics, which governs the subatomic realm of particles….

Quanta magazine reports:
The wormhole emerged like a hologram out of quantum bits of information, or “qubits,” stored in tiny superconducting circuits. By manipulating the qubits, the physicists then sent information through the wormhole, they reported Wednesday in the journal Nature. The team, led by Maria Spiropulu of the California Institute of Technology, implemented the novel “wormhole teleportation protocol” using Google’s quantum computer, a device called Sycamore housed at Google Quantum AI in Santa Barbara, California. With this first-of-its-kind “quantum gravity experiment on a chip,” as Spiropulu described it, she and her team beat a competing group of physicists who aim to do wormhole teleportation with IBM and Quantinuum’s quantum computers.

When Spiropulu saw the key signature indicating that qubits were passing through the wormhole, she said, “I was shaken.”

The experiment can be seen as evidence for the holographic principle, a sweeping hypothesis about how the two pillars of fundamental physics, quantum mechanics and general relativity, fit together…. The holographic principle, ascendant since the 1990s, posits a mathematical equivalence or “duality” between the two frameworks. It says the bendy space-time continuum described by general relativity is really a quantum system of particles in disguise. Space-time and gravity emerge from quantum effects much as a 3D hologram projects out of a 2D pattern. Indeed, the new experiment confirms that quantum effects, of the type that we can control in a quantum computer, can give rise to a phenomenon that we expect to see in relativity — a wormhole….

To be clear, unlike an ordinary hologram, the wormhole isn’t something we can see. While it can be considered “a filament of real space-time,” according to co-author Daniel Jafferis of Harvard University, lead developer of the wormhole teleportation protocol, it’s not part of the same reality that we and the Sycamore computer inhabit. The holographic principle says that the two realities — the one with the wormhole and the one with the qubits — are alternate versions of the same physics, but how to conceptualize this kind of duality remains mysterious. Opinions will differ about the fundamental implications of the result. Crucially, the holographic wormhole in the experiment consists of a different kind of space-time than the space-time of our own universe. It’s debatable whether the experiment furthers the hypothesis that the space-time we inhabit is also holographic, patterned by quantum bits.
“I think it is true that gravity in our universe is emergent from some quantum [bits] in the same way that this little baby one-dimensional wormhole is emergent” from the Sycamore chip, Jafferis said. “Of course we don’t know that for sure. We’re trying to understand it.”
Here’s how principal investigator Spiropulu summarizes their experiment. “We found a quantum system that exhibits key properties of a gravitational wormhole yet is sufficiently small to implement on today’s quantum hardware.”

It’s possible that this prompted her immune system to produce antibodies against her baby’s blood — antibodies that then crossed the placenta and harmed her child, ultimately leading to its loss. It may seem implausible that such a thing could happen, but many decades ago, before doctors had a better understanding of blood groups, it was much more common. Through studying the mother’s blood sample, along with a number of others, scientists were able to unpick exactly what made her blood different, and in the process confirmed a new set of blood grouping — the “Er” system, the 44th to be described. You’re probably familiar with the four main blood types — A, B, O, and AB. But this isn’t the only blood classification system. There are many ways of grouping red blood cells based on differences in the sugars or proteins that coat their surface, known as antigens.

The grouping systems run concurrently, so your blood can be classified in each — it might, for instance, be type O in the ABO system, positive (rather than negative) under the Rhesus system, and so on. Thanks to differences in antigens, if someone receives incompatible blood from a donor, for example, the recipient’s immune system may detect those antigens as foreign and react against them. This can be highly dangerous, and is why donated blood needs to be a suitable match if someone is having a transfusion. On average, one new blood classification system has been described by researchers each year during the past decade. These newer systems tend to involve blood types that are mind-bogglingly rare but, for those touched by them, just knowing that they have such blood could be lifesaving. This is the story of how scientists unraveled the mystery of the latest blood system — and why it matters.

Using previously done research on salamanders, Lynne and colleagues at City University of New York and Princeton examined how the arrow of time is represented in interactions between the amphibians’ neurons in response to watching a movie. Their research is soon to be published in the journal Physical Review Letters. On one hand, it’s somewhat obvious that an arrow of time would be biologically produced. “To be alive, almost, you have to have an arrow of time because you develop from a baby to an adult, and you’re constantly moving and taking in stimuli,” Lynne said. Indeed, entropy here is irreversible — you cannot go back. What the team found was anything but intuitive, however.

Lynne and colleagues looked at a separate 2015 study where researchers had salamanders watch two different movies. One depicted a scene of fish swimming around, similar to what a salamander might experience in everyday life. As in the real world, the video had a clear arrow of time — that is, if you watched it in reverse, it would look different than if you played it forwards. The other video contained only a gray screen with a black, horizontal bar in the middle of the screen, which moved quickly up and down in a random, jittery way. This video didn’t have an obvious arrow of time. A major question for the researchers was if they could pick out signs of “local irreversibility” in interactions between small groups of retinal neurons in response to this stimulus. Would interactions with irreversibility — they would look different if played in reverse, having an “arrow of time” — present in simpler or more complex interactions between neurons? “You can go look at a system and you can ask: are the more complicated interactions strongly producing the arrow of time, or is it the simpler dynamics?” said Lynn.

The researchers found that the interactions between simple pairs of neurons primarily determined the arrow of time, no matter which movie the salamanders watched. In fact, the authors found a stronger arrow of time for the neurons when salamanders watched the video with the gray screen and black bar — in other words, the video without an arrow of time in its content elicited a greater arrow of time in the neurons. “We naively thought that if the stimulus has a stronger arrow of time, that would show up on your retina,” said Lynn. “But it was the opposite. So that’s why it was surprising to us.” While the researchers can’t say for sure why this is, Lynn said that it might be because salamanders are more used to seeing something like the fish movie, and processing the more artificial movie took greater energy. In a more disordered system, which would have a greater arrow of time, more energy is consumed. “Being alive will still define an arrow of time,” Lynne said, no matter the stimulus.

Although most psychedelics remain illegal under federal law, the Food and Drug Administration is weighing potential therapeutic uses for compounds like psilocybin, LSD and MDMA, the drug better known as Ecstasy. Dr. Michael Bogenschutz, director at NYU Langone Center for Psychedelic Medicine and the study’s lead investigator, said the findings offered hope for the nearly 15 million Americans who struggle with excessive drinking — roughly 5 percent of all adults. Excessive alcohol use kills an estimated 140,000 people each year.

In the current study, the team looked to level up the number of graphene layers. They fabricated two new structures, made from four and five graphene layers, respectively. Each structure is stacked alternately, similar to the shifted cheese sandwich of twisted trilayer graphene. The team kept the structures in a refrigerator below 1 kelvin (about -273 degrees Celsius), ran electrical current through each structure, and measured the output under various conditions, similar to tests for their bilayer and trilayer systems. Overall, they found that both four- and five-layer twisted graphene also exhibit robust superconductivity and a flat band. The structures also shared other similarities with their three-layer counterpart, such as their response under a magnetic field of varying strength, angle, and orientation.

These experiments showed that twisted graphene structures could be considered a new family, or class of common superconducting materials. The experiments also suggested there may be a black sheep in the family: The original twisted bilayer structure, while sharing key properties, also showed subtle differences from its siblings. For instance, the group’s previous experiments showed the structure’s superconductivity broke down under lower magnetic fields and was more uneven as the field rotated, compared to its multilayer siblings. The team carried out simulations of each structure type, seeking an explanation for the differences between family members. They concluded that the fact that twisted bilayer graphene’s superconductivity dies out under certain magnetic conditions is simply because all of its physical layers exist in a “nonmirrored” form within the structure. In other words, there are no two layers in the structure that are mirror opposites of each other, whereas graphene’s multilayer siblings exhibit some sort of mirror symmetry. These findings suggest that the mechanism driving electrons to flow in a robust superconductive state is the same across the twisted graphene family.

In this case, they arranged the carbon atoms into the shape of the organic compound polyacetylene, which is made up of a repeating chain of carbon and hydrogen atoms with an alternating pattern of single and double carbon bonds between them. To simulate those bonds, the team placed the carbon atoms at different distances apart. Next, the researchers ran an electrical current through the circuit to check whether it would match the signature of a natural polyacetylene molecule — and sure enough, it did. In other tests, the team created two different versions of the chain by cutting bonds at different places, and the resulting currents matched theoretical predictions perfectly. The significance of this new quantum circuit, the team says, is that it could be used to study more complicated molecules, which could eventually yield new materials, pharmaceuticals, or catalysts. This 10-atom version is right on the limit of what classical computers can simulate, so the team’s plans for a 20-atom quantum circuit would allow for simulation of more complex molecules for the first time. The research has been published in the journal Nature.