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Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:32am

An illuminated water droplet creates an 'optical atom'

Shining light on a water droplet creates effects analogous to what happens in an atom. This can help us understand how atoms work, write researchers from the  in a new journal article published in Physical Review Letters.

If you whisper by the wall in the dome of St Paul's Cathedral in London, you'll discover that the sound bounces off the dome's walls all the way around and is audible on the opposite side. Which is why the Cathedral's dome has been dubbed "the whispering gallery."

The same effect is achieved when a beam of light is shone into a water droplet. Rays of light bounce off the inner wall of the water droplet over and over again, going around and around inside the droplet. When its circumference is a multiple of the light's wavelength, a resonance phenomenon occurs, just like the sound inside the Cathedral's dome, making the droplet shine brighter.

In their  experiments with laser light, we could see that the light is trapped inside the water droplet. When the droplet shrinks due to evaporation, it appears to flash every time its size is right to create the resonance phenomenon.

You cannot change the size of the dome in St. Paul's Cathedral, but a water droplet changes size as it evaporates. The researchers then discovered how the droplet flashed in a way similar to what occurs when an electron is emitted from an atom when illuminated by light of varying wavelengths. They were also able to use a quantum mechanics analogy to explain how the resonances—the size of the droplet when the scattering was greatest—correspond to the energy levels of an atom. This makes the droplet a model of an atom with the added bonus that its size can be varied. It provides deeper insights into how light scatters while being a model for understanding how atoms work.

Javier Tello Marmolejo et al, Fano Combs in the Directional Mie Scattering of a Water Droplet, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.130.043804

Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:27am

The neuroscientists used electroencephalography—or EEG—sensors attached to the head to measure electrical activity in the brain of 80 study participants, and sample brainwave rhythms.

The team took alpha waves readings. The mid-range of the brainwave spectrum, this wave frequency tends to dominate when we are awake and relaxed.

Alpha waves oscillate between eight to twelve hertz: a full cycle every 85-125 milliseconds. However, every person has their own peak alpha frequency within that range.

Scientists used these readings to create an optical "pulse": a white square flickering on a dark background at the same tempo as each person's individual alpha wave.

Participants got a 1.5-second dose of personalized pulse to set their brain working at its natural rhythm—a technique called "entrainment"—before being presented with a tricky quick-fire cognitive task: trying to identify specific shapes within a barrage of visual clutter.

A brainwave cycle consists of a peak and trough. Some participants received pulses matching the peak of their waves, some the trough, while some got rhythms that were either random or at the wrong rate (a little faster or slower). Each participant repeated over 800 variations of the cognitive task, and the neuroscientists measured how quickly people improved.

The learning rate for those locked into the right rhythm was at least three times faster than for all the other groups. When participants returned the next day to complete another round of tasks, those who learned much faster under entrainment had maintained their higher performance level.

The intervention itself is very simple, just a brief flicker on a screen, but when we hit the right frequency plus the right phase alignment, it seems to have a strong and lasting effect.

Importantly, entrainment pulses need to chime with the trough of a brainwave. Scientists think this is the point in a cycle when neurons are in a state of "high receptivity".

Elizabeth Michael et al, Learning at your brain's rhythm: individualized entrainment boosts learning for perceptual decisions, Cerebral Cortex (2022). DOI: 10.1093/cercor/bhac426

Part 2

Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:24am

Tuning into brainwave rhythms speeds up learning in adults, study finds

Scientists have shown for the first time that briefly tuning into a person's individual brainwave cycle before they perform a learning task dramatically boosts the speed at which cognitive skills improve.

Calibrating rates of information delivery to match the natural tempo of our brains increases our capacity to absorb and adapt to new information, according to the team behind the study.

The researchers say that these techniques could help us retain "neuroplasticity" much later in life and advance lifelong learning.

Each brain has its own natural rhythm, generated by the oscillation of neurons working together. Scientists simulated these fluctuations so the brain is in tune with itself—and in the best state to flourish. 

The brain's plasticity is the ability to restructure and learn new things, continually building on previous patterns of neuronal interactions. By harnessing brainwave rhythms, it may be possible to enhance flexible learning across the lifespan, from infancy to older adulthood.

Part 1

Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:15am

The majority of the results fit perfectly with the currently accepted best theory of the universe.

But there are also signs of a crack—one that has been suggested in the past by other analyses, too.

It seems like there are slightly less fluctuations in the current universe, than we would predict assuming our standard cosmological model anchored to the early universe.

That is, if you make a model incorporating all the currently accepted physical laws, then take the readings from the beginning of the universe and extrapolate it forward through time, the results look slightly different from what we actually measure around us today.

Specifically, today's readings find the universe is less "clumpy"—clustering in certain areas rather than evenly spread out—than the model would predict.

If other studies continue to find the same results, scientists say, it may mean there is something missing from our existing model of the universe, but the results are not yet to the statistical level that scientists consider to be ironclad. That will take further study.

 Y. Omori et al, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck . I. Construction of CMB lensing maps and modeling choices, Physical Review D (2023). DOI: 10.1103/PhysRevD.107.023529

C. Chang et al, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck . II. Cross-correlation measurements and cosmological constraints, Physical Review D (2023). DOI: 10.1103/PhysRevD.107.023530

T. M. C. Abbott et al, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck . III. Combined cosmological constraints, Physical Review D (2023). DOI: 10.1103/PhysRevD.107.023531

Part 2

Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:14am

Scientists release new map of all the matter in the universe

When the universe began, matter was flung outward and gradually formed the planets, stars and galaxies that we know and love today. Scientists are very interested in tracing the path of this matter; by seeing where all the matter ended up, they can try to recreate what happened and what forces would have had to have been in play. By carefully assembling a map of that matter today, scientists can try to understand the forces that shaped the evolution of the universe.

A group of scientists have released one of the most precise measurements ever made of how matter is distributed across the universe today.

Combining data from two major telescope surveys of the universe, the Dark Energy Survey and the South Pole Telescope, the analysis involved more than 150 researchers and is published as a set of three articles Jan. 31 in Physical Review D.

Among other findings, the analysis indicates that matter is not as "clumpy" as we would expect based on our current best model of the universe, which adds to a body of evidence that there may be something missing from our existing standard model of the universe.

Combining two different methods of looking at the sky reduces the chance that the results are thrown off by an error in one of the forms of measurement. "It functions like a cross-check, so it becomes a much more robust measurement than if you just used one or the other. In both cases, the analysis looked at a phenomenon called "gravitational lensing." As light travels across the universe, it can be slightly bent as it passes objects with lots of gravity, like galaxies.

This method catches both regular matter and dark matter—the mysterious form of matter that we have only detected due to its effects on regular matter—because both regular and dark matter exert gravity.
By rigorously analyzing these two sets of data, the scientists could infer where all the matter ended up in the universe. It is more precise than previous measurements—that is, it narrows down the possibilities for where this matter wound up—compared to previous analyses.
Part 1

Comment by Dr. Krishna Kumari Challa on February 1, 2023 at 9:04am

Scientists couple terahertz radiation with spin waves

An international research team has developed a new method for the efficient coupling of terahertz waves with much shorter wavelengths, so-called spin waves. As the experts report in the journal Nature Physics, their experiments, in combination with theoretical models, clarify the fundamental mechanisms of this process previously thought impossible. The results are an important step for the development of novel, energy-saving spin-based technologies for data processing.

Ruslan Salikhov et al, Coupling of terahertz light with nanometre-wavelength magnon modes via spin–orbit torque, Nature Physics (2023). DOI: 10.1038/s41567-022-01908-1

Comment by Dr. Krishna Kumari Challa on January 31, 2023 at 11:48am

Voles fall in love, even without oxytocin

Gene-edited prairie voles that can’t detect the ‘love hormone’ oxytocin still form monogamous relationships and care for their pups. The study challenges decades of research suggesting that prairie vo.... The study might help scientists to understand oxytocin’s role in humans. It has been trialled as a treatment for conditions that can affect social attachment. “There’s a sort of eerie similarity between prairie vole social behaviours and human social behaviours,” says neuroscientist Nirao Shah. “Prairie voles are one of the few mammalian species that exhibit social attachment.”

https://www.nature.com/articles/d41586-023-00197-9?utm_source=Natur...

Berendzen, K. M. et al. Neuron https://doi.org/10.1016/j.neuron.2022.12.011 (2023)

Comment by Dr. Krishna Kumari Challa on January 31, 2023 at 10:39am

Why do the cores of stars spin more slowly than expected?

Under certain conditions, the cores of stars contract. When this happens, they start to spin faster than the external layers of the star. However, the study of oscillations in stars, asteroseismology, has uncovered an astonishing phenomenon: The cores of such stars actually rotate more slowly than calculations predict. Why is this so?

Three  scientists from CNRS, INRIA and ENS-PSL have studied this question and report their findings in an article published in Science on January 19, 2023. Their numerical stimulations, which model plasma flow in the deep layers of a star, have shown that the slowing down of the core can be produced by an internal magnetic field. More specifically, plasma flow can amplify a magnetic field to the point where it generates strong turbulent motions. Such turbulence may further amplify the magnetic field until it causes the star's core to spin down.

The results obtained with the research team's simulations are also in agreement with asteroseismological observations of many stars. In addition, the simulations show that the magnetic field would be hidden by the outer layers of the star, which explains why no magnetic field of this kind has yet been measured with current techniques.

More information: Ludovic Petitdemange et al, Spin-down by dynamo action in simulated radiative stellar layers, Science (2023). DOI: 10.1126/science.abk2169

Comment by Dr. Krishna Kumari Challa on January 31, 2023 at 10:33am

The cognitive effects of air pollution- Even chess experts perform worse when air quality is lower, suggesting a negative effect on cognition

Here's something else chess players need to keep in check: air pollution.

That's the bottom line of a newly published study co-authored by an MIT researcher, showing that chess players perform objectively worse and make more suboptimal moves, as measured by a computerized analysis of their games, when there is more fine particulate matter in the air.

Fine particulate matter refers to tiny particles 2.5 microns or less in diameter, notated as PM_2.5. They are often associated with burning matter—whether through internal combustion engines in autos, coal-fired power plants, forest fires, indoor cooking through open fires, and more. The World Health Organization estimates that air pollution leads to over 4 million premature deaths worldwide every year, due to cancer, cardiovascular problems, and other illnesses.

More specifically, given a modest increase in fine particulate matter, the probability that chess players will make an error increases by 2.1 percentage points, and the magnitude of those errors increases by 10.8%. In this setting, at least, cleaner air leads to clearer heads and sharper thinking.

When individuals are exposed to higher levels of air pollution, they make more more mistakes, and they make larger mistakes, this study finds. Moreover, air pollution may affect people in settings where they might not think it makes a difference. It's not like you have to live next to a power plant. You can live miles away and be affected.

And while the focus of this particular study is tightly focused on chess players, the authors write in the paper that the findings have "strong implications for high-skilled office workers," who might also be faced with tricky cognitive tasks in conditions of variable air pollution. 

Steffen Künn et al, Indoor Air Quality and Strategic Decision Making, Management Science (2023). DOI: 10.1287/mnsc.2022.4643

Comment by Dr. Krishna Kumari Challa on January 31, 2023 at 10:19am

The model could be used for a virtual patient trial, allowing researchers to generate dozens of patients and then predict which ones would have hyper- or hypokalemia based on different controls.

"A lot of our models are pieces of a bigger picture," said Anita Layton, professor of applied mathematics and Canada 150 Research Chair in mathematical biology and medicine. "This model is one new and exciting piece in helping us understand how our incredibly complex internal systems work."

The model is especially exciting because it allows scientists to test something called the muscle-kidney cross-talk signal hypothesis. Scientists have hypothesized that skeletal muscles, which are responsible for most of the potassium storage in the body, can directly signal to the kidneys that it's time to excrete excess when too much potassium is stored, and vice versa. When the math researchers tested the hypothesis in their model, it more accurately reflected existing biological data regarding potassium homeostasis, suggesting that muscle-kidney cross talk might be an essential piece in the puzzle of potassium regulation.

The study was published in PLOS Computational Biology.

More information: Melissa M. Stadt et al, A mathematical model of potassium homeostasis: Effect of feedforward and feedback controls, PLOS Computational Biology (2022). DOI: 10.1371/journal.pcbi.1010607

Part 2

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