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Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 7:56am

Weak equivalence principle violated in gravitational waves

The Weak equivalence principle (WEP) is a key aspect of classical physics. It states that when particles are in freefall, the trajectories they follow are entirely independent of their masses. However, it is not yet clear whether this property also applies within the more complex field of quantum mechanics. In new research published in EPJ C, James Quach at the University of Adelaide, Australia, proves theoretically that the WEP can be violated by quantum particles in gravitational waves—the ripples in spacetime caused by colossal events such as merging black holes.

James Q. Quach, Fisher information and the weak equivalence principle of a quantum particle in a gravitational wave, The European Physical Journal C (2020). DOI: 10.1140/epjc/s10052-020-08530-6

https://phys.org/news/2020-10-weak-equivalence-principle-violated-g...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 7:54am

Physicists circumvent centuries-old theory to cancel magnetic fields

A team of scientists including two physicists has found a way to circumvent a 178-year old theory which means they can effectively cancel magnetic fields at a distance. They are the first to be able to do so in a way which has practical benefits.

The work is hoped to have a wide variety of applications. For example, patients with neurological disorders such as Alzheimer's or Parkinson's might in future receive a more accurate diagnosis. With the ability to cancel out 'noisy' external magnetic fields, doctors using magnetic field scanners will be able to see more accurately what is happening in the brain.

"Earnshaw's Theorem" from 1842 limits the ability to shape magnetic fields. The team were able to calculate an innovative way to circumvent this theory in order to effectively cancel other magnetic fields which can confuse readings in experiments.

Rosa Mach-Batlle et al, Tailoring Magnetic Fields in Inaccessible Regions, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.177204

https://phys.org/news/2020-10-physicists-circumvent-centuries-old-t...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 7:45am

Researchers develop artificial cell on a chip

Researchers have developed a precisely controllable system for mimicking biochemical reaction cascades in cells. Using microfluidic technology, they produce miniature polymeric reaction containers equipped with the desired properties. This 'cell on a chip' is useful not only for studying processes in cells, but also for the development of new synthetic pathways for chemical applications or for biological active substances in medicine.

In order to survive, grow and divide, cells rely on a multitude of different enzymes that catalyze many successive reactions. Given the complexity of processes in living cells, it is impossible to determine when specific enzymes are present at what concentrations and what their optimum proportions are relative to one another. Instead, researchers use smaller, synthetic systems as models in order to study these processes. These synthetic systems simulate the subdivision of living cells into separate compartments.

developed a new strategy for producing these synthetic systems. Writing in the journal Advanced Materials, the researchers describe how they create various synthetic miniature reaction containers, known as vesicles, which—taken as a whole—serve as models of a cell.

"Unlike in the past, this is not based on the self-assembly of vesicles. "Rather, we've developed efficient microfluidic technology in order to produce enzyme-loaded vesicles in a controlled manner." The new method allows the researchers to tweak the size and composition of the different vesicles so that various biochemical reactions can take place inside them without influencing one another—like in the different compartments of a cell.

In order to manufacture the desired vesicles, the scientist feed the various components into tiny channels on a silicon-glass chip. On this chip, all of the microchannels come together at a junction. If the conditions are configured correctly, this arrangement produces an aqueous emulsion of uniformly sized polymer droplets that are formed at the point of intersection.

 Elena C. Santos et al. Combinatorial Strategy for Studying Biochemical Pathways in Double Emulsion Templated Cell‐Sized Compartments, Advanced Materials (2020). DOI: 10.1002/adma.202004804

https://phys.org/news/2020-10-artificial-cell-chip.html?utm_source=...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 7:33am

Judges' decisions in sport focus more on vigour than skill

Judges' decisions are an integral part of combat sports, from boxing and wrestling to mixed martial arts (MMA). However, a new study suggests the rate at which competitors fight is more likely to result in judges awarding victory than the skill with which they attack their opponents.

They analysed almost 550 men's and women's mixed martial arts contests, taking place between February 2019 and March 2020, using data collated for the Ultimate Fighting Championship (UFC).

That data included the percentage of significant strikes landed that land firmly on the target (a measure of skill), the number of strikes attempted per second (a measure of vigour), the outcome of the fight and whether it was determined by knockout or judges' decision.

The results showed that in all fights, winners fought more vigorously than losers but this performance trait was more important for fights resolved via judges' decisions compared with those ending as a result of a knockout or technical knockout.

Fighting skilfully (landing more significant strikes) also increased their chance of winning—with skilful fighting even enhancing the effect of vigour on success—but despite this, the rate of attack was consistently the dominant factor determining success in fights evaluated by judges.

Perceived and actual fighting ability: Determinants of success via decision, knockout or submission in human combat sports, Biology Letters (2020). royalsocietypublishing.org/doi … .1098/rsbl.2020.0443

https://phys.org/news/2020-10-decisions-sport-focus-vigour-skill.ht...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 7:08am

Researchers examine the decline in average body temperature among healthy adults over the past two decades

Why human body temperatures are decreasing among healthy adults over the past two decades

In the nearly two centuries since German physician Carl Wunderlich established 98.6°F (37 C) as the standard "normal" body temperature, it has been used by parents and doctors alike as the measure by which fevers—and often the severity of illness—have been assessed.

In more recent years, lower body temperatures have been widely reported in healthy adults. A 2017 study among 35,000 adults in the United Kingdom found average body temperature to be lower (97.9°F / 36.6 C), and a 2019 study showed that the normal body temperature in Americansis about 97.5°F (36.4 C). Several similar reports from around the world have been noticed in recent times.

In less than two decades we're seeing about the same level of decline as that observed in the U.S. over approximately two centuries. Researchers’ analysis is based on a large sample of 18,000 observations of almost 5,500 adults, and adjust for multiple other factors that might affect body temperature, such as ambient temperature and body mass.

Declines might be due to the rise of modern health care and lower rates of lingering mild infections now as compared to the past. It could be that people are in better condition, so their bodies might be working less to fight infection. Or greater access to antibiotics and other treatments means the duration of infection is shorter now than in the past. Consistent with that argument, Researchers found that having a respiratory infection in the early period of the study led to having a higher body temperature than having the same respiratory infection more recently.

It's also possible that greater use of anti-inflammatory drugs like ibuprofen may reduce inflammation, though the researchers found that the temporal decline in body temperature remained even after their analyses accounted for biomarkers of inflammation.

Another possibility is that our bodies don't have to work as hard to regulate internal temperature because of air conditioning in the summer and heating in the winter.

While Tsimane body temperatures do change with time of year and weather patterns, the Tsimane still do not use any advanced technology for helping to regulate their body temperature. They do, however, have more access to clothes and blankets.

The researchers were initially surprised to find no single "magic bullet" that could explain the decline in body temperature. "It's likely a combination of factors—all pointing to improved conditions.

 M. Gurven el al., "Rapidly declining body temperature in a tropical human population," Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.abc6599

https://phys.org/news/2020-10-decline-average-body-temperature-heal...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 6:58am

Researchers link poor memory to attention lapses and media multitasking

Scientists are now able to predict whether an individual will remember or forget something based on their neural activity and pupil size.

As we navigate our lives, we have these periods in which we're frustrated because we're not able to bring knowledge to mind, expressing what we know. Fortunately, science now has tools that allow us to explain why an individual, from moment to moment, might fail to remember something stored in their memory.

To monitor attention lapses in relation to memory, 80 study subjects between the ages of 18 to 26 had their pupils measured and their brain activity monitored via an electroencephalogram (EEG) - specifically, the brain waves referred to as posterior alpha power—while performing tasks like recalling or identifying changes to previously studied items.

Increases in alpha power in the back of your skull have been related to attention lapses, mind wandering, distractibility and so forth. Constrictions in pupil diameter—in particular before you do different tasks—are related to failures of performance like slower reaction times and more mind wandering.

This work demonstrates a correlation, not causation. You can't say that heavier media multitasking causes difficulties with sustained attention and memory failures, though we are increasingly learning more about the directions of the interactions. 

one direction that the field as a whole has been heading in is a focus on what happens before learning or, as in this case, before remembering even occurs. That's because memory heavily depends on goal-directed cognition—we essentially need to be ready to remember, have attention engaged and a memory goal in mind—in order to retrieve our memories.

"While it's logical that attention is important for learning and for remembering, an important point here is that the things that happen even before you begin remembering are going to affect whether or not you can actually reactivate a memory that is relevant to your current goal.

conscious awareness of attentiveness, readiness to remember and limiting potential distractions allow individuals to influence their mindsets and alter their surroundings to improve their memory performance."Hacking" memory. While these relatively straightforward strategies can be applied now, the researchers note that there may eventually be targeted attention-training exercises or interventions that people can employ to help them stay engaged. These are referred to as "closed-loop interventions" and are an active area of research.

 advances in measuring attentional states and their impacts on the use of goals to guide remembering also hold promise for a better understanding of disease or health conditions that affect memory.

More information: Memory failure predicted by attention lapsing and media multitasking, Nature (2020). DOI: 10.1038/s41586-020-2870-z , www.nature.com/articles/s41586-020-2870-z

https://medicalxpress.com/news/2020-10-link-poor-memory-attention-l...

Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 6:49am

Researchers break magnetic memory speed record

Spintronic devices are attractive alternatives to conventional computer chips, providing digital information storage that is highly energy efficient and also relatively easy to manufacture on a large scale. However, these devices, which rely on magnetic memory, are still hindered by their relatively slow speeds, compared to conventional electronic chips.

Now an international team of researchers has reported a new technique for magnetization switching—the process used to "write" information into magnetic memory—that is nearly 100 times faster than state-of-the-art spintronic devices. The advance could lead to the development of ultrafast magnetic memory for computer chips that would retain data even when there is no power.

In the study, the researchers report using extremely short, 6-picosecond electrical pulses to switch the magnetization of a thin film in a magnetic device with great energy efficiency. A picosecond is one-trillionth of a second.

 Kaushalya Jhuria et al. Spin–orbit torque switching of a ferromagnet with picosecond electrical pulses, Nature Electronics (2020). DOI: 10.1038/s41928-020-00488-3

https://techxplore.com/news/2020-10-magnetic-memory.html?utm_source...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:21pm

**'Fireball' meteorite contains pristine extraterrestrial organic compounds

O n the night of January 16, 2018, a fireball meteor streaked across the sky over the Midwest and Ontario before landing on a frozen lake in Michigan. Scientists used weather radar to find where the pieces landed and meteorite hunters were able to collect the meteorite quickly, before its chemical makeup got changed by exposure to liquid water. And, as a new paper in Meteoritics & Planetary Science shows, that gave scientists a glimpse of what space rocks are like when they're still in outer space—including a look at pristine organic compounds that could tell us about the origins of life.

This meteorite is special because it fell onto a frozen lake and was recovered quickly. It was very pristine. Researchers could see the minerals weren't much altered and later found that it contained a rich inventory of extraterrestrial organic compounds. These kinds of organic compounds were likely delivered to the early Earth by meteorites and might have contributed to the ingredients of life.

Scientists aren't sure how the organic (carbon-containing) compounds responsible for life on Earth got here; one theory is that they hitched their way here on meteorites. That doesn't mean that the meteorites themselves contain extraterrestrial life; rather, some of the organic compounds that help make up life might have first formed in an asteroid that later fell to Earth.

As soon as the thing lands, it gets covered with microbes and life from Earth. We have meteorites with lichens growing on them. So the fact that this meteorite was collected so quickly after it fell, and that it landed on ice rather than in the dirt, helped keep it cleaner.

https://phys.org/news/2020-10-fireball-meteorite-pristine-extraterr...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:15pm

60-year-old limit to lasers overturned by quantum researchers

A team of Australian quantum theorists has shown how to break a bound that had been believed, for 60 years, to fundamentally limit the coherence of lasers.

The coherence of a laser beam can be thought of as the number of photons (particles of light) emitted consecutively into the beam with the same phase (all waving together). It determines how well it can perform a wide variety of precision tasks, such as controlling all the components of a quantum computer.

Now, in a paper published in Nature Physics, the researchers from Griffith University and Macquarie University have shown that new quantum technologies open the possibility of making this coherence vastly larger than was thought possible.

It 's shown now that  the true limit imposed by quantum mechanics is that the coherence cannot be greater than the fourth power of the number of photons stored in the laser.

 Travis J. Baker et al. The Heisenberg limit for laser coherence, Nature Physics (2020). DOI: 10.1038/s41567-020-01049-3

https://phys.org/news/2020-10-year-old-limit-lasers-overturned-quan...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:03pm

Random effects key to containing epidemics

To control an epidemic, authorities will often impose varying degrees of lockdown. In a paper in the journal Chaos, scientists have discovered, using mathematics and computer simulations, why dividing a large population into multiple subpopulations that do not intermix can help contain outbreaks without imposing contact restrictions within those local communities.

The key idea is that, at low infection numbers, fluctuations can alter the course of the epidemics significantly, even if you expect an exponential increase in infection numbers on average. 

When infection numbers are high, random effects can be ignored. But subdividing a population can create communities so small that the random effects matter.

When a large population is divided into smaller communities, these random effects completely change the dynamics of the full population. Randomness causes peak infection numbers to be brought way down.

"Stochastic effects on the dynamics of an epidemic due to population subdivision," Chaos (2020). DOI: 10.1063/5.0028972

https://phys.org/news/2020-10-random-effects-key-epidemics.html?utm...

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