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Comment by Dr. Krishna Kumari Challa on October 29, 2021 at 8:37am

10 UNESCO forests emit more CO2 than they soak up

Sites containing some of the world's most treasured forests, including the Yosemite National Park and Indonesia's Sumatra rainforest, have been emitting more heat-trapping carbon dioxide than they have absorbed in recent years, a U.N.-backed report said.

According to the report released Thursday, factors like logging, wildfires and clearance of land for agriculture are to blame. The excess carbon turns up from just 10 of 257 forests classified among UNESCO World Heritage sites.

The 10 sites that were net sources of carbon from 2001 to 2020 were the Tropical Rainforest in Sumatra; the Río Platano Biosphere Reserve in Honduras; Grand Canyon National Park and Yosemite National Park in the United States: Waterton Glacier International Peace Park in Canada and the U.S.; the Barberton Makhonjwa Mountains in South Africa; Kinabalu Park in Malaysia; the Uvs Nuur Basin in Russia and Mongolia; the Greater Blue Mountains area of Australia; and Morne Trois Pitons National Park in Dominica.

The Switzerland-based International Union for Conservation of Nature and UNESCO, the U.N.'s cultural and educational agency, said their report provides the first-ever assessment of greenhouse gases produced and absorbed in UNESCO-listed forests. The study was based on information collected through on-site monitoring and from satellites.

The study adds to growing signs that human activities and the fallout from climate change —which scientists say has made weather extremes like drought and wildfires more likely—have transformed some natural carbon sinks that suck up CO₂ from the air into net sources of it over the last two decades.

The report's finding that even some of the most iconic and best protected forests, such as those found in World Heritage sites, can actually contribute to climate change is alarming.

This is because of cutting trees and clearing forests , which produce CO2 and  also largely due to a bout of devastating wildfires in these areas in recent years.

https://phys.org/news/2021-10-unesco-forests-emit-co2.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on October 29, 2021 at 8:28am

Technology to produce unbreakable screens

Cracked phone screens could become a thing of the past thanks to breakthrough research.

A team of researchers  have unlocked the technology to produce next-generation composite glass for lighting LEDs and smartphone, television and computer screens.

The findings will enable the manufacture of glass screens that are not only unbreakable but also deliver crystal clear image quality.

The discovery was a huge step forward in perovskite nanocrystal technology as previously, researchers were only able to produce this technology in the bone-dry atmosphere of a laboratory setting. The emitting materials are made from nanocrystals, called lead-halide perovskites.

They can harvest sunlight and concert it into renewable electricity—playing a vital role in low-cost and high-efficiency new generation solar cells and many promising applications like lighting. Unfortunately, these nanocrystals are extremely sensitive to light, heat, air and water—even water vapor in our air would kill the current devices in a matter of minutes. But this team of chemical engineers and material scientists has developed a process to wrap or bind the nanocrystals in porous glass. This process is key to stabilizing the materials, enhancing its efficiency and inhibits the toxic lead ions from leaching out from the materials.

At present QLED or quantum dot light-emitting diode screens are considered the top performer for image display and performance. This research will enable us to improve on this nanocrystal technology by offering stunning picture quality and strength.

Jingwei Hou et al, Liquid-phase sintering of lead halide perovskites and metal-organic framework glasses, Science (2021). DOI: 10.1126/science.abf4460

https://phys.org/news/2021-10-technology-unbreakable-screens.html?u...

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 8:45am

The Pupil in Your Eye Can Perceive Numerical Information, Not Just Light

You might know that the size of the pupils in our eyes changes depending on how well lit our environment is, but there's more to the story: Scientists have now discovered that the pupil also shifts in size depending on how many objects we're observing.

The more objects in a scene, the bigger the pupil grows, as if to better accommodate everything that it has to look at. This "perceived numerosity" is a simple and automatic reflex, the new research shows.

In a new study, researchers observed the pupil sizes of 16 participants while they looked at pictures of dots. In some of the pictures, the dots were linked together in dumbbell shapes – creating the illusion that there were fewer objects – and pupil size then shrank. This result shows that numerical information is intrinsically related to perception.

As for where this reaction comes from, it's likely to be linked to the need for survival – most species are thought to have a dedicated 'number sense' that enables them to spot enemies in the wild, find food, get back home, and more besides.

When it comes to humans, being able to weigh up numbers is something that seems to appear as soon as a few hours after birth – even if you're terrible at math, you have a built-in aptitude for judging numerosity, and it appears the dilation of our pupils is part of a response to that. When we look around, we spontaneously perceive the form, size, movement and color of a scene. Equally spontaneously, we perceive the number of items before us. This ability, shared with most other animals, is an evolutionary fundamental: it reveals immediately important quantities, such as how many apples there are on the tree, or how many enemies are attacking.

And there's lots more to explore here as well. Our eyes seem to be more sensitive to the number of items we're looking at rather than how they're spaced or arranged, which is another reaction that can be analyzed in future studies.

https://www.nature.com/articles/s41467-021-26261-4

https://www.sciencealert.com/pupil-size-changes-depending-on-how-ma...

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 8:33am

Researchers create mirror-image peptides that can neutralize SARS-CoV-2

Researchers at the University of Toronto have created chemical compounds that can neutralize SARS-CoV-2 and several of its variants.

In a recent paper published in the Journal of Medicinal Chemistry, the researchers report the creation of D-peptides that neutralize the virus and stop infection of cultured human cells.

Known as mirror-image peptides, the compounds have chemical properties that make them suitable for the development of low-cost antiviral therapeutics.

A big advantage of mirror-image peptides is their long stability and that they are relatively cheap to produce.

Peptides are similar to proteins in that they are composed of the same amino-acids building blocks. But they are smaller than protein molecules. They can be designed to bind virtually any molecular target and with a greater specificity than small-molecule drugs, reducing the risk of side effects. In this way, peptides are similar to antibodies but are at least 100 times cheaper to produce thanks to their small size. The combination of low cost and easy scaling of manufacturing makes peptides attractive, particularly for low-income countries.

But there's a caveat. In the body, peptides are rapidly degraded by the enzymes that have evolved to stamp out harmful versions produced by bacteria and other pathogens. But science has found a solution in mirror-image peptides that are resistant to degradation.

For reasons that remain unclear, all naturally occurring amino acids exist in a left-handed configuration, as defined by the direction in which they rotate. Consequently, all proteins and peptides are also left-handed—and known as L-peptides. These mirror-image molecules are manufactured from synthetic D-amino acids strung together in the same way as their left-handed counterparts.  They can be engineered to bind the same targets with undiminished specificity. The main difference is that their unusual geometry makes them resistant to enzymes in the bloodstream that break down normal L-peptides. 

Pedro A. Valiente et al, Computational Design of Potent D-Peptide Inhibitors of SARS-CoV-2, Journal of Medicinal Chemistry (2021). DOI: 10.1021/acs.jmedchem.1c00655

https://phys.org/news/2021-10-mirror-image-peptides-neutralize-sars...

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Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 8:22am

Study confirms mistaken identity may explain why sharks bite humans

World-first research testing a simulated 'shark vision' model on swimming patterns of humans, seals and sea-lions, confirms theories that when great white sharks bite humans, it may be a case of mistaken identity.

Great white sharks are also called white sharks—and together with bull and tiger sharks, they account for by far the most bites on humans.

Researchers found that surfers, swimmers and pinnipeds (seals and sea-lions) on the surface of the ocean will look the same to a white shark looking up from below, because these sharks can't see fine details or colours.

Sharks use a range of sensory cues to distinguish between different objects and zero in on their food, and these differ in sensitivity between shark species. White sharks are highly visual—and juveniles are more dangerous to humans than are older, larger white sharks which have better vision.

When white sharks reach around 2.5 meters in length, their jaws begin to harden so they can take on bigger prey like seals. They need to develop a search image for these prey items and combine that with other sensory information; it's a learning process that could be prone to mistakes. Understanding why shark bites occur can help us find ways to prevent them, while keeping both humans and sharks safer.

 Laura A. Ryan et al, A shark's eye view: testing the 'mistaken identity theory' behind shark bites on humans, Journal of The Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0533

https://phys.org/news/2021-10-mistaken-identity-sharks-humans.html?...

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 7:54am

Atoms .... see them!

Comment by Dr. Krishna Kumari Challa on October 28, 2021 at 6:56am

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:59am

 quantum sensing can work without a high-powered vacuum system. This shrinks the package to a practical size without sacrificing reliability.

Instead of a powered vacuum pump, which whisks away molecules that leak in and wreck measurements, a pair of devices called getters use chemical reactions to bind intruders. The getters are each about the size of a pencil eraser so they can be tucked inside two narrow tubes sticking out of the titanium package. They also work without a power source.

To further keep out contaminants, Schwindt partnered with Sandia materials scientists to build the chamber out of titanium and sapphire. These materials are especially good at blocking out gasses like helium, which can squeeze through stainless steel and Pyrex glass. Funding was provided by Sandia’s Laboratory Directed Research and Development program.

Construction took sophisticated fabrication techniques that Sandia has honed to bond advanced materials for nuclear weapons components. And like a nuclear weapon, the titanium chamber must work reliably for years.

The Sandia team is continuing to monitor the device. Their goal is to keep it sealed and operational for five years, an important milestone toward showing the technology is ready to be fielded. In the meantime, they’re exploring ways to streamline manufacturing.

https://www.eurekalert.org/news-releases/932743

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Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:59am

This device could usher in GPS-free navigation

A new era of navigation.

For over a year, the avocado-sized vacuum chamber has contained a cloud of atoms at the right conditions for precise navigational measurements. It is the first device that is small, energy-efficient and reliable enough to potentially move quantum sensors — sensors that use quantum mechanics to outperform conventional technologies — from the lab into commercial use, said Sandia National Laboratories scientist Peter Schwindt.

Sandia developed the chamber as a core technology for future navigation systems that don’t rely on GPS satellite.

Countless devices around the world use GPS for wayfinding. It’s possible because atomic clocks, which are known for extremely accurate timekeeping, hold the network of satellites perfectly in sync.

But GPS signals can be jammed or spoofed, potentially disabling navigation systems on commercial and military vehicles alike, Schwindt said.

So instead of relying on satellites,  future vehicles might keep track of their own position. They could do that with on-board devices as accurate as atomic clocks, but that measure acceleration and rotation by shining lasers into small clouds of rubidium gas like this one.

Atomic accelerometers and gyroscopes already exist, but they’re too bulky and power-hungry to use in an airplane’s navigation system. That’s because they need a large vacuum system to work, one that needs thousands of volts of electricity.

“Quantum sensors are a growing field, and there are lots of applications you can demonstrate in the lab. But when you move it into the real world there are lots of problems you have to solve. Two are making the sensor compact and rugged. The physics takes place all in a cubic centimeter (0.06 cubic inches) of volume, so anything larger than that is wasted space.”

part1

Comment by Dr. Krishna Kumari Challa on October 27, 2021 at 9:53am

Underwater Drone Flies AND Swims

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