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Comment by Dr. Krishna Kumari Challa on August 26, 2022 at 11:38am

Eye movements in REM sleep mimic gazes in the dream world

When our eyes move during REM sleep, we’re gazing at things in the dream world our brains have created, according to a new study by researchers.

REM sleep — named for the rapid eye movements associated with it — has been known since the 1950s to be the phase of sleep when dreams occur. But the purpose of the eye movements has remained a matter of much mystery and debate. 

This new work showed that these eye movements aren’t random. They’re coordinated with what's happening in the virtual dream world of the mouse.This work gives us a glimpse into the ongoing cognitive processes in the sleeping brain and at the same time solves a puzzle that’s triggered the curiosity of scientists for decades.

some experts hypothesized that these REM movements may be following scenes in the dream world, but there was little way to test it, and the experiments that could be done (noting a dreamers’ eye direction and then waking them up to ask where they were looking in the dream) provided contradictory results. Many researchers wrote off REM movements as random actions, perhaps to keep the eyelids lubricated.

Given much more advanced technology, researchers now were able to look at “head direction” cells in the brains of mice, who also experience REM sleep. These cells act something like a compass, and their activity shows researchers which direction the mouse perceives itself as heading. 

The team simultaneously recorded data from these cells about the mouse’s heading directions while monitoring its eye movements. Comparing them, they found that the direction of eye movements and of the mouse’s internal compass were precisely aligned during REM sleep, just as they do when the mouse is awake and moving around.  

The research team found that the same parts of the brain — and there are many of them — coordinate during both dreaming and wakefulness, lending credence to the idea that dreams are a way of integrating information gathered throughout the day. 

How those brain regions work together to produce this generative ability is the mystery .

https://www.science.org/doi/10.1126/science.abp8852

Comment by Dr. Krishna Kumari Challa on August 26, 2022 at 9:16am

Physicists entangle more than a dozen photons efficiently

.Physicists  have managed to entangle more than a dozen photons efficiently and in a defined way. They are thus creating a basis for a new type of quantum computer. 

The phenomena of the quantum world, which often seem bizarre from the perspective of the common everyday world, have long since found their way into technology. For example, entanglement: a quantum-physical connection between particles that links them in a strange way over arbitrarily long distances. It can be used, for example, in a quantum computer—a computing machine that, unlike a conventional computer, can perform numerous mathematical operations simultaneously. However, in order to use a quantum computer profitably, a large number of entangled particles must work together. They are the basic elements for calculations, so-called qubits.

Photons, the particles of light, are particularly well suited for this because they are robust by nature and easy to manipulate. Researchers  have now succeeded in taking an important step towards making photons usable for technological applications such as quantum computing: For the first time, a research team generated up to 14 entangled photons in a defined way and with high efficiency.

The trick to this experiment was that they used a single atom to emit the photons and interweave them in a very specific way. To do this, the researchers placed a rubidium atom at the center of an optical cavity—a kind of echo chamber for electromagnetic waves. With laser light of a certain frequency, the state of the atom could be precisely addressed. Using an additional control pulse, the researchers also specifically triggered the emission of a photon that is entangled with the quantum state of the atom.

They  repeated this process several times and in a previously determined manner.

In between, the atom was manipulated in a certain way—in technical jargon: rotated. In this way, it was possible to create a chain of up to 14 light particles that were entangled with each other by the atomic rotations and brought into a desired state.

Because the chain of photons emerged from a single atom, it could be produced in a deterministic way. This means: in principle, each control pulse actually delivers a photon with the desired properties.

 Philip Thomas et al, Efficient generation of entangled multiphoton graph states from a single atom, Nature (2022). DOI: 10.1038/s41586-022-04987-5

Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 12:36pm

New research on the risks of lead exposure from bullets used in big game hunting

The lead in some bullets used for hunting deer, moose, and elk is toxic to the humans who eat the harvested meat and to scavenger animals that feast on remains left in the field.

Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 9:56am

Here's what a black hole sounds like, according to NASA.

Data Sonification: Black Hole at the Center of the Perseus Galaxy Cluster (X-ray)

Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 9:44am

Experiment on YouTube reveals potential to 'inoculate' users against misinformation

Fact-checkers can only rebut a fraction of the falsehoods circulating online. We need to teach people to recognize the misinformation playbook, so they understand when they are being misled.

https://phys.org/news/2022-08-youtube-reveals-potential-inoculate-m...

Comment by Dr. Krishna Kumari Challa on August 24, 2022 at 12:01pm

Study shows 90% of marine species at risk of extinction by 2100 if greenhouse gas emissions are not curbed

An international team of researchers has found that approximately 90% of all marine life on Earth will be at risk of extinction by 2100 if greenhouse gas emissions are not curbed. In their paper published in the journal Nature Climate Change, the group outlines their study of thousands of marine species and how greenhouse gas emissions might impact them in the future.

Greenhouse gas emissions impact the world's climate in two ways. They raise the temperature of the atmosphere (and by extension, Earth's surfaces and bodies of water) by holding in heat, and in the case of CO₂ emissions, they make water more acidic, like carbonated soft drinks. And as emissions continue to be pumped into the atmosphere despite dire warnings from scientists around the world, more research is being conducted to learn about its possible impact. In this new effort, the researchers took a broad look at the impact of greenhouse gas emissions on ocean life.

The work involved estimating the impact of certain levels of greenhouse gas emissions on marine life in the future. They looked specifically at 25,000 species, including fish, bacteria, plants and protozoans living in the top 100 meters of the world's oceans. They found that under the worst scenario, in which emissions lead to global atmospheric temperature increases of 3 to 5 degrees Celsius, approximately 90% of all marine life will disappear. They also found that if emissions are cut to the extent outlined by the Paris Climate Agreement, which would keep global temperature increases to below 2 degrees Celsius, then the risk of extinction would be reduced by approximately 98%.

The researchers also found that larger top predators are more at risk than smaller predators, as are fish species  in areas where they are heavily fished by humans. Those at lowest risk, on the other hand, include small, short-lived species. Notably, Earth has not seen a die-off as great as these projections since the Great Dying 252 million years ago.

Daniel G. Boyce et al, A climate risk index for marine life, Nature Climate Change (2022). DOI: 10.1038/s41558-022-01437-y

Comment by Dr. Krishna Kumari Challa on August 24, 2022 at 11:58am

Your Next Wooden Chair Could Arrive Flat, Then Dry Into a 3D Shape

Comment by Dr. Krishna Kumari Challa on August 23, 2022 at 8:23am

Researchers discover a material that can learn like the brain

Researchers have discovered that Vanadium Dioxide (VO₂), a compound used in electronics, is capable of "remembering" the entire history of previous external stimuli. This is the first material to be identified as possessing this property, although there could be others.

A PhD student made a chance discovery during his research on phase transitions in Vanadium Dioxide (VO₂). VO₂ has an insulating phase when relaxed at room temperature, and undergoes a steep insulator-to-metal transition at 68 °C, where its lattice structure changes. Classically, VO₂ exhibits a volatile memory: "the material reverts back to the insulating state right after removing the excitation" . For his thesis, he set out to discover how long it takes for VO₂ to transition from one state to another. But his research led him down a different path: after taking hundreds of measurements, he observed a memory effect in the material's structure.

In his experiments, the student applied an electric current  to a sample of VO₂. The current moved across the material, following a path until it exited on the other side. As the current heated up the sample, it caused the VO₂ to change state. And once the current had passed, the material returned to its initial state.

He then applied a second current pulse to the material, and saw that the time it took to change state was directly linked to the history of the material. The VO₂ seemed to 'remember' the first phase transition and anticipate the next. The researchers didn't expect to see this kind of memory effect, and it has nothing to do with electronic states but rather with the physical structure of the material. It's a novel discovery: no other material behaves in this way.

The researchers went on to find that VO₂ is capable of remembering its most recent external stimulus for up to three hours. The memory effect could in fact persist for several days, but we don't currently have the instruments needed to measure that.

The research team's discovery is important because the memory effect they observed is an innate property of the material itself. Engineers rely on memory to perform calculations of all kinds, and materials that could enhance the calculation process by offering greater capacity, speed and miniaturization are in high demand. VO₂ ticks all three of these boxes. What's more, its continuous, structural memory sets it apart from conventional materials that store data as binary information dependent on the manipulation of electronic states.

The researchers performed a host of measurements to arrive at their findings. They also corroborated their results by applying the new method to different materials at other laboratories around the world. This discovery replicates well what happens in the brain, as VO₂ switches act just like neurons.

Mohammad Samizadeh Nikoo, Electrical control of glass-like dynamics in vanadium dioxide for data storage and processing, Nature Electronics (2022). DOI: 10.1038/s41928-022-00812-z. www.nature.com/articles/s41928-022-00812-z

Comment by Dr. Krishna Kumari Challa on August 22, 2022 at 10:13am

How Quinine Fights Malaria

Comment by Dr. Krishna Kumari Challa on August 20, 2022 at 10:14am

Non-nutritive sweeteners affect human microbiomes and can alter glycemic responses

Since the late 1800s non-nutritive sweeteners have promised to deliver all the sweetness of sugar with none of the calories. They have long been believed to have no effect on the human body, but researchers publishing in the journal Cell on August 19 challenge this notion by finding that these sugar substitutes are not inert, and, in fact, some can alter human consumers' microbiomes in a way that can change their blood sugar levels.

In 2014 researchers found that non-nutritive sweeteners affected the microbiomes of mice in ways that could impact their glycemic responses. They were interested in whether these results would also be found in humans.

To address this important question, the researchers  carefully screened over 1,300 individuals for those who strictly avoid non-nutritive sweeteners in their day-to-day lives, and identified a cohort of 120 individuals. These participants were broken into six groups: two controls and four who ingested well below the FDA daily allowances of either aspartame, saccharin, stevia, or sucralose.

In subjects consuming the non-nutritive sweeteners, scientists could identify very distinct changes in the composition and function of gut microbes, and the molecules they secret into peripheral blood. This seemed to suggest that gut microbes in the human body are rather responsive to each of these sweeteners.

When they looked at consumers of non-nutritive sweeteners as groups, they found that two of the non-nutritive sweeteners, saccharin and sucralose, significantly impacted glucose tolerance in healthy adults. Interestingly, changes in the microbes were highly correlated with the alterations noted in people's glycemic responses.

To establish causation, the researchers transferred microbial samples from the study subjects to germ-free mice—mice that have been raised in completely sterile conditions and have no microbiome of their own.

The results were quite striking. In all of the non-nutritive sweetener groups, but in none of the controls, when the researchers transferred into these sterile mice the microbiome of the top responder individuals collected at a time point in which they were consuming the respective non-nutritive sweeteners, the recipient mice developed glycemic alterations that very significantly mirrored those of the donor individuals. In contrast, the bottom responders' microbiomes were mostly unable to elicit such glycemic responses. These results suggest that the microbiome changes in response to human consumption of non-nutritive sweetener may, at times, induce glycemic changes in consumers in a highly personalized manner.

The effects of the sweeteners will vary person to person because of the incredibly unique composition of our microbiome.

 Eran Elinav, Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance, Cell (2022). DOI: 10.1016/j.cell.2022.07.016. www.cell.com/cell/fulltext/S0092-8674(22)00919-9

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