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Comment by Dr. Krishna Kumari Challa on July 30, 2021 at 10:18am

New exotic matter particle, a tetraquark, discovered

Yesterday  the LHCb experiment at CERN has presented a new discovery at the European Physical Society Conference on High Energy Physics (EPS-HEP). The new particle discovered by LHCb, labeled as T_cc⁺, is a tetraquark—an exotic hadron containing two quarks and two antiquarks. It is the longest-lived exotic matter particle ever discovered, and the first to contain two heavy quarks and two light antiquarks.

Quarks are the fundamental building blocks from which matter is constructed. They combine to form hadrons, namely baryons, such as the proton and the neutron, which consist of three quarks, and mesons, which are formed as quark-antiquark pairs. In recent years a number of so-called exotic hadrons—particles with four or five quarks, instead of the conventional two or three—have been found. The present  discovery is of a particularly unique exotic hadron.

The new particle  contains two charm quarks and an up and a down antiquark. 

https://home.cern/news/news/physics/twice-charm-long-lived-exotic-p...

Comment by Dr. Krishna Kumari Challa on July 30, 2021 at 9:15am

More carbon emissions will kill more people; here's how many

A just-published study coins a new metric: the "mortality cost of carbon." That is, how many future lives will be lost—or saved—depending on whether we increase or decrease our current carbon emissions. If the numbers hold up, they are quite high. The study was published recently in the journal Nature Communications.

Researchers saw a major gap in current estimates of the social cost of carbon—the dollar figure that economists attach to each ton of emissions, based on future damages it is expected to inflict. A complex and highly malleable number, the social cost of carbon underpins how governments worldwide formulate climate policies,  by suggesting how much we should be willing to pay today in order to avert damages in the future. Yet, while recent studies project that climate change will cause millions of premature deaths, current estimates of the social cost of carbon rely on outdated research that does not include those projections. Scientists now attempts to add in the new data.

Based on the decisions made by individuals, businesses or governments, this tells you how many lives will be lost, or saved. It quantifies the mortality impact of those decisions. It brings this question down to a more personal, understandable level.

Assuming that emissions continue to increase on their current high path, researchers came up with a number: 2.26×10^-4, or 0.000226 excess deaths this century per metric ton of carbon dioxide emitted beyond the current rate of emissions. That is: For every 4,434 metric tons of CO₂ that we add beyond the 2020 rate of emissions, we will kill one person. 

This implies that we must cut emissions in a big way now, and reach full decarbonization by 2050. The result would be only 2.4 degrees of warming by 2100. As a result, by scientists' calculation, excess deaths would drop to 9 million by 2100—a saving of 74 million lives.

All these figures are subject to political finagling.

https://news.climate.columbia.edu/2021/07/29/more-carbon-emissions-...

Comment by Dr. Krishna Kumari Challa on July 29, 2021 at 12:24pm

Dark mode may not save battery life as much as anticipated

When Android and Apple operating system updates started giving users the option to put their smartphones in dark mode, the feature showed potential for saving the battery life of newer phones with screens that allow darker-colored pixels to use less power than lighter-colored pixels.

But dark mode is unlikely to make a big difference to battery life with the way that most people use their phones on a daily basis, says a new study by  researchers.

That doesn't mean that dark mode can't be helpful, though.

 Researchers found that switching from light mode to dark mode saves only 3%-9% power on average for several different OLED smartphones.

This percentage is so small that most users wouldn't notice the slightly longer battery life. But the higher the brightness when switching from light mode to dark mode, the higher the energy savings.

Pranab Dash et al, How much battery does dark mode save?, Proceedings of the 19th Annual International Conference on Mobile Systems, Applications, and Services (2021). DOI: 10.1145/3458864.3467682

https://techxplore.com/news/2021-07-dark-mode-battery-life.html?utm...

Comment by Dr. Krishna Kumari Challa on July 29, 2021 at 12:18pm

Motivation depends on how the brain processes fatigue

How do we decide whether or not an activity which requires work is 'worth the effort'? Researchers  have shown that the willingness to work is not static, and depends upon the fluctuating rhythms of fatigue.

Fatigue—the feeling of exhaustion from doing effortful tasks—is something we all experience daily. It makes us lose motivation and want to take a break. Although scientists understand the mechanisms the brain uses to decide whether a given task is worth the effort, the influence of fatigue on this process is not yet well understood.

The research team conducted a study to investigate the impact of fatigue on a person's decision to exert effort. They found that people were less likely to work and exert effort—even for a reward—if they were fatigued. The results are published in Nature Communications.

Intriguingly, the researchers found that there were two different types of fatigue that were detected in distinct parts of the brain. In the first, fatigue is experienced as a short-term feeling, which can be overcome after a short rest. Over time, however, a second, longer term feeling builds up, stops people from wanting to work, and doesn't go away with short rests.

Tanja Müller et al, Neural and computational mechanisms of momentary fatigue and persistence in effort-based choice, Nature Communications (2021). DOI: 10.1038/s41467-021-24927-7

Comment by Dr. Krishna Kumari Challa on July 29, 2021 at 12:08pm

Earth's 'vital signs' worsening as humanity's impact deepens

The global economy's business-as-usual approach to climate change has seen Earth's "vital signs" deteriorate to record levels, an influential group of scientists said recently, warning that several climate tipping points were now imminent.

The researchers, part of a group of more than 14,000 scientists who have signed on to an initiative declaring a worldwide climate  emergency, said that governments had consistently failed to address the root cause of climate change: "the overexploitation of the Earth".

Of 31 "vital signs"—key metrics of planetary health that include greenhouse gas emissions, glacier thickness, sea-ice extent and deforestation—they found that 18 hit record highs or lows.

For example, despite a dip in pollution linked to the pandemic, levels of atmospheric CO2 and methane hit all-time highs in 2021.

Greenland and Antarctica both recently showed all-time low levels of ice mass, and glaciers are melting 31 percent faster than they did just 15 years ago, the authors said.

Both ocean heat and global sea levels set new records since 2019, and the annual loss rate of the Brazilian Amazon reached a 12-year high in 2020.

Echoing previous research, they said that forest degradation linked to fire, drought and logging was causing parts of the Brazilian Amazon to now act as a source of carbon, rather than absorb the gas from the atmosphere.

Livestock such as cows and sheep are now at record levels, numbering more than four billion and with a mass exceeding that of all humans and wild land mammals combined, they said.

We need to respond to the evidence that we are hitting climate tipping points with equally urgent action to decarbonise the global economy and start restoring instead of destroying nature, they stressed.

The researchers said there was "mounting evidence that we are nearing or have already crossed" a number of climate tipping points.

https://academic.oup.com/bioscience/advance-article/doi/10.1093/bio...

https://phys.org/news/2021-07-earth-vital-worsening-humanity-impact...

Comment by Dr. Krishna Kumari Challa on July 29, 2021 at 10:51am

The Hidden Beauty of Rainbows

Comment by Dr. Krishna Kumari Challa on July 28, 2021 at 10:35am

Physicists Have Figured Out How We Could Make Antimatter Out of Light

A new study by scientists has demonstrated how researchers may be able to create an accelerating jet of antimatter from light.

A team of physicists has shown that high-intensity lasers can be used to generate colliding gamma photons – the most energetic wavelengths of light – to produce electron-positron pairs. This, they say, could help us understand the environments around some of the Universe's most extreme objects: neutron stars.

The process of creating a matter-antimatter pair of particles – an electron and a positron – from photons is called the Breit-Wheeler process, and it's extremely difficult to achieve experimentally.

The probability of it taking place when two photons collide is very small. You need very high-energy photons, or gamma rays, and a lot of them, in order to maximize the chances of observation.

We don't yet have the capability to build a gamma-ray laser, so the photon-photon Breit-Wheeler process currently remains experimentally unachieved. But a team of physicists led by Yutong He of the University of California, San Diego (UC San Diego) has proposed a new workaround that, according to their simulations, could actually work.

It consists of a plastic block, carved with a pattern of criss-crossing channels on the micrometer scale. Two powerful lasers, one on either side of the block, fire strong pulses at this target.

"When the laser pulses penetrate the sample, each of them accelerates a cloud of extremely fast electrons. 

These two electron clouds then race toward each other with full force, interacting with the laser propagating in the opposite direction."

The resulting collision is so energetic that it produces a cloud of gamma photons. These gamma photons should collide with each other to produce electron-positron pairs,  in accordance with Einstein's theory of general relativity.

Even more excitingly, this process should generate powerful magnetic fields that collimate the positrons (rather than the electrons) into strongly accelerated, jet-shaped beams. In a distance of just 50 micrometers, the researchers found, the acceleration should increase the energy of the particles to one gigaelectronvolt.

Using a complex computer simulation, the researchers tested their model, and found that it should work, even when using less powerful lasers than previous proposals.

Not only would the collimation and acceleration of the positron beam improve the detection rate of the particles, but it bears a strong similarity to the powerful collimated particle jets beamed out by strongly magnetic, rapidly rotating neutron stars known as pulsars.

Scientists believe that processes that take place close to these stars could result in clouds of gamma radiation, similar to their proposed experiment.

https://www.nature.com/articles/s42005-021-00636-x

https://www.sciencealert.com/physicists-have-figured-out-how-we-cou...

Comment by Dr. Krishna Kumari Challa on July 28, 2021 at 9:50am

Fingertip-powered wearable

Comment by Dr. Krishna Kumari Challa on July 28, 2021 at 9:47am

'Good cholesterol' may protect liver

 The body's so-called good cholesterol may be even better than we realize. New research from Washington University School of Medicine in St. Louis suggests that one type of high-density lipoprotein (HDL) has a previously unknown role in protecting the liver from injury. This HDL protects the liver by blocking inflammatory signals produced by common gut bacteria. The study was published July 23 in the journal Science. HDL is mostly known for mopping up cholesterol in the body and delivering it to the liver for disposal. But in the new study, the researchers identified a special type of HDL called HDL3 that, when produced by the intestine, blocks gut bacterial signals that cause liver inflammation. If not blocked, these bacterial signals travel from the intestine to the liver, where they activate immune cells that trigger an inflammatory state, which leads to liver damage. Even though HDL has been considered good cholesterol,’ drugs that increase overall HDL levels have fallen out of favor in recent years because of clinical trials that showed no benefit in cardiovascular disease.  study suggests that raising levels of this specific type of HDL, and specifically raising it in the intestine, may hold promise for protecting against liver disease, which, like heart disease, also is a major chronic health problem.

Any sort of intestinal damage can impact how a group of microbes called Gram-negative bacteria can affect the body. Such microbes produce an inflammatory molecule called lipopolysaccharide that can travel to the liver via the portal vein. The portal vein is the major vessel that supplies blood to the liver, and it carries most nutrients to the liver after food is absorbed in the intestine. Substances from gut microbes may travel along with nutrients from food to activate immune cells that trigger inflammation. In this way, elements of the gut microbiome may drive liver disease, including fatty liver disease and liver fibrosis, in which the liver develops scar tissue.

https://researchnews.cc/news/8017/-Good-cholesterol--may-protect-li...

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Comment by Dr. Krishna Kumari Challa on July 28, 2021 at 9:39am

When our defences turn on us

When the body becomes the target of its own defensive arsenal, medicine must step in. This Nature Outlook explores why autoimmune disease is around three times more common in women than in men, the genetic variants that increase the risk of autoimmunity and how the microbes in our gut might sometimes be to blame. It also reveals how the possible links between long COVID and the immune system might finally prove that viruses can spark autoimmune disease.

Nature | Full collection

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