Comment

Comment by Dr. Krishna Kumari Challa on December 26, 2020 at 8:56am

When light and atoms share a common vibe

An especially counter-intuitive feature of quantum mechanics is that a single event can exist in a state of superposition – happening both here and there, or both today and tomorrow.

Such superpositions are hard to create, as they are destroyed if any kind of information about the place and time of the event leaks into the surrounding – and even if nobody actually records this information. But when superpositions do occur, they lead to observations that are very different from that of classical physics, questioning down to our very understanding of space and time.

Scientists demonstrated a state of vibration that exists simultaneously at two different times, and evidence this quantum superposition by measuring the strongest class of quantum correlations between light beams that interact with the vibration.

The researchers used a very short laser-pulse to trigger a specific pattern of vibration inside a diamond crystal. Each pair of neighboring atoms oscillated like two masses linked by a spring, and this oscillation was synchronous across the entire illuminated region. To conserve energy during this process, a light of a new color is emitted, shifted toward the red of the spectrum.

This classical picture, however, is inconsistent with the experiments. Instead, both light and vibration should be described as particles, or quanta: light energy is quantized into discrete photons while vibrational energy is quantized into discrete phonons (named after the ancient Greek “photo = light” and “phono = sound”).

The process described above should therefore be seen as the fission of an incoming photon from the laser into a pair of photon and phonon – akin to nuclear fission of an atom into two smaller pieces.

But it is not the only shortcoming of classical physics. In quantum mechanics, particles can exist in a superposition state, like the famous Schrödinger cat being alive and dead at the same time.

Even more counterintuitive: two particles can become entangled, losing their individuality. The only information that can be collected about them concerns their common correlations. Because both particles are described by a common state (the wavefunction), these correlations are stronger than what is possible in classical physics. It can be demonstrated by performing appropriate measurements on the two particles. If the results violate a classical limit, one can be sure they were entangled.

In the new study, EPFL researchers managed to entangle the photon and the phonon (i.e., light and vibration) produced in the fission of an incoming laser photon inside the crystal. To do so, the scientists designed an experiment in which the photon-phonon pair could be created at two different instants. Classically, it would result in a situation where the pair is created at time t1 with 50% probability, or at a later time t2 with 50% probability.

But here comes the “trick” played by the researchers to generate an entangled state. By a precise arrangement of the experiment, they ensured that not even the faintest trace of the light-vibration pair creation time (t1 vs. t2) was left in the universe. In other words, they erased information about t1 and t2. Quantum mechanics then predicts that the phonon-photon pair becomes entangled, and exists in a superposition of time t1andt2. This prediction was beautifully confirmed by the measurements, which yielded results incompatible with the classical probabilistic theory.

By showing entanglement between light and vibration in a crystal that one could hold in their finger during the experiment, the new study creates a bridge between our daily experience and the fascinating realm of quantum mechanics.

https://researchnews.cc/news/4299/When-light-and-atoms-share-a-comm...

Comment by Dr. Krishna Kumari Challa on December 26, 2020 at 8:24am

Different people will show different views on the best science breakthroughs of the year. We present some of them here.

One such view: The biggest and most important scientific breakthroughs of 2020

https://au.news.yahoo.com/most-important-scientific-breakthroughs-o...

Comment by Dr. Krishna Kumari Challa on December 26, 2020 at 7:40am

The Year's Biggest Breakthroughs in Physics

Comment by Dr. Krishna Kumari Challa on December 26, 2020 at 7:30am

The Year's Biggest Breakthroughs in Biology

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 10:09am

How could stars help us detect life on other planets?

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 9:45am

There’s no magic way to boost your energy. But ‘perineum sunning’ isn’t the answer

Perineum sunning is said to have roots in an ancient Taoist practice, where the perineum, or “Hui Yin”, is regarded as a gateway where energy enters and exits the body.

It’s probably also related to the idea that the sun has healing powers. Many years ago sun exposure was recommended after childbirth, and sunlamps were used in labour wards to ostensibly aid healing. But there was no evidence for this.

Some of the appeal of the trend might also lie in the fact many pale-skinned people like to be tanned.

That said, tanning is not the motivation behind the perineum sunning wellness trend. People who do it say it gives their body an intense dose of vitamin D, and therefore a significant energy boost.

It can also supposedly increase creativity, improve sleep, and even promote a healthy libido, among other reported benefits.

---

Read more: Your vagina cleans itself: why vagina cleaning fads are unnecessary...

---

But there’s no evidence to support any of these supposed benefits. Although there have been no scientific studies on perineum sunning to date. 

However, we can’t dismiss the placebo effect. For example, if someone thinks sunning their perineum will improve their libido, it probably will.

The main risk of perineum sunning is sunburn. Sun-exposed skin adapts to exposure to ultraviolet (UV) light by forming melanin, the natural protective pigment in skin that reduces the risk of sunburn. So when you get UV light on a part of your skin that’s not accustomed to sun exposure, you’re much more likely to get burnt.

If you do get sunburnt in this sensitive area, it’s likely to be very sore. You won’t be able to have sex for about a week, and it might sting to urinate.

And of course, UV is a known carcinogen, which is why nowadays we discourage any kind of tanning. Sunburn can increase your risk of skin cancer, and chronic UV exposure can raise skin cancer risk even without causing sunburn.

https://theconversation.com/theres-no-magic-way-to-boost-your-energ...

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 9:41am

Study on health effects and citizen resistance during the lockdown

https://medicalxpress.com/news/2020-12-publish-health-effects-citiz...

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 9:38am

Can't draw a mental picture? Aphantasia causes blind spots in the mind's eye

If you were asked to draw a picture of your grandparents' living room from memory, could you do it? For most people, certain details are easy to visualize: "There's a piano in the corner, a palm by the window and two seashells on the coffee table."

But for others, such a task would be almost impossible. These individuals have a rare condition called aphantasia, which prevents them from easily recreating images in their mind's eye—in fact, the phrase "mind's eye" may be meaningless to them.

"Some individuals with aphantasia have reported that they don't understand what it means to 'count sheep' before going to bed." They thought it was merely an expression, and had never realized until adulthood that other people could actually visualize sheep without seeing them.

The differences in the memory experiment were striking: Individuals with typical imagery usually drew the most salient objects in the room with a moderate amount of detail, like color and key design elements (a green carpet, rather than a rectangle).

Individuals with aphantasia had a harder time—they could place a few objects in the room, but their drawings were often simpler, and relied at times on written descriptions. For example, some wrote the word "window" inside an outline of a window rather than drawing the windowpanes.

While people with aphantasia lack visual imagery, they appear to have intact spatial memory, which is distinct from imagery and may be stored differently . People who are congenitally blind, for example, can still describe the layout of a familiar room.

even though people with aphantasia remembered fewer objects overall, they also made fewer mistakes: They didn't create any false memories of objects that hadn't been in any of the rooms, and placed objects in the correct location—but the wrong room—only three times.

"One possible explanation could be that because aphantasics have trouble with this task, they rely on other strategies like verbal-coding of the space. Their verbal representations and other compensatory strategies might actually make them better at avoiding false memories."

Wilma A. Bainbridge et al. Quantifying aphantasia through drawing: Those without visual imagery show deficits in object but not spatial memory, Cortex (2020). DOI: 10.1016/j.cortex.2020.11.014

https://medicalxpress.com/news/2020-12-mental-picture-aphantasia-mi...

**

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 9:34am

Astrocytes eat connections to maintain plasticity in adult brains Developing brains constantly sprout new neuronal connections called synapses as they learn and remember. Important connections—the ones that are repeatedly introduced, such as how to avoid danger—are nurtured and reinforced, while connections deemed unnecessary are pruned away. Adult brains undergo similar pruning, but it was unclear how or why synapses in the adult brain get eliminated.

Love and hate in the mouse brain Mounting behavior, that awkward thrusting motion dogs sometimes do against your leg, is usually associated with sexual arousal in animals, but this is not always the case. New research by Caltech neuroscientists that explores the motivations behind mounting behavior in mice finds that sometimes there is a thin line between love and hate (or anger) in the mouse brain. **

Comment by Dr. Krishna Kumari Challa on December 25, 2020 at 9:28am

Scientists pioneer new method of measuring electricity in cells

Electricity is a key ingredient in living bodies. We know that voltage differences are important in biological systems; they drive the beating of the heart and allow neurons to communicate with one another. But for decades, it wasn't possible to measure voltage differences between organelles—the membrane-wrapped structures inside the cell—and the rest of the cell.

A pioneering technology now developed  allows researchers to peer into cells to see how many different organelles use voltages to carry out functions.

Tiny sensors were built to travel inside cells and report back on what's happening, so that researchers can understand how cells work—and how they break down in disease or disorders. Previously, they have built such machines to study neurons and lysosomes, among others.

In this case, they decided to use the technique to investigate the electric activities of the organelles inside live cells.

In the membranes of neurons, there are proteins called ion channels which act as gateways for charged ions to enter and exit the cell. These channels are essential for neurons to communicate. Previous research had shown that organelles have similar ion channels, but we weren't sure what roles they played.

The researchers' new tool, called Voltair, makes it possible to explore this question further. It works as a voltmeter measuring the voltage difference of two different areas inside a cell. Voltair is constructed out of DNA, which means it can go directly into the cell and access deeper structures.

In their initial studies, the researchers looked for membrane potentials—a difference in voltage inside an organelle versus outside. They found evidence for such potentials in several organelles, such as trans-Golgi networks and recycling endosomes, that were previously thought not to have membrane potentials at all.

The membrane potential in organelles could play a larger role—maybe it helps organelles communicate.

Anand Saminathan et al. A DNA-based voltmeter for organelles, Nature Nanotechnology (2020). DOI: 10.1038/s41565-020-00784-1

https://phys.org/news/2020-12-scientists-method-electricity-cells.h...

• ‹ Previous
• 1
• …
• 672
• 673
• 674
• 675
• 676
• …
• 1054
• Next ›
• Page