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Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:56am

Understanding the role quantum tunneling plays in the building and rearrangements of molecules could have important ramifications in the calculations of energy release in nuclear reactions, such as those involving hydrogen in stars and fusion reactors here on Earth.

While we've modeled this phenomenon for examples involving reactions between a negatively charged form of deuterium – an isotope of hydrogen containing a neutron – and dihydrogen or H₂, proving the numbers experimentally requires a challenging level of precision.

To accomplish this, Wild and his colleagues cooled negative deuterium ions to a temperature that brought them close to a standstill before introducing a gas made of hydrogen molecules.

Without heat, the deuterium ion was far less likely to have the energy required to force hydrogen molecules into a rearrangement of atoms. Yet it also forced the particles into sitting quietly near one another, giving them more time to bond through tunneling.

In their experiment, scientists give possible reactions in the trap about 15 minutes and then determine the amount of hydrogen ions formed. From their number, they can deduce how often a reaction has occurred.

That figure is just over 5 x 10^-20 reactions per second taking place in each cubic centimeter, or around one tunneling event for around every hundred billion collisions. So not a lot. Though the experiment does back up previous modeling, confirming a benchmark that can be used in predictions elsewhere.

Given tunneling plays a fairly important role in a diverse range of nuclear and chemical reactions, much of which is also likely to occur out in the cold depths of space, getting a precise grip on the factors at play gives us a more solid grounding to base our predictions on.

https://www.nature.com/articles/s41586-023-05727-z

part 2

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:54am

For The First Time Ever, Physicists See Molecules Form Through Quantum Tunneling

Chemistry takes effort. Whether it's by raising the temperature, increasing the odds that compatible atoms will collide in a heated smash-up, or increasing the pressure and squeezing them together, building molecules usually demands a certain cost in energy.

Quantum theory does provide a workaround if you're patient. And a team of researchers from the University of Innsbruck in Austria has finally seen the quantum tunneling in action in a world-first experiment measuring the merger of deuterium ions with hydrogen molecules.

Tunneling is a quirk of the quantum universe that makes it seem like particles can pass through obstacles that are ordinarily too hard to overcome.

In chemistry, this obstacle is the energy required for atoms to bond with one another, or with existing molecules.

Yet theory says that, in extremely rare instances, it's possible for atoms in close proximity to 'tunnel' their way through this energy barrier and connect without any effort.

Quantum mechanics allows particles to break through the energetic barrier due to their quantum mechanical wave properties, and a reaction occurs.

Quantum waves are the ghosts that drive the behaviors of objects like electrons, photons, and even entire groups of atoms, blurring their existence before any observation so they sit not in any one precise place but occupy a continuum of possible positions.

This blurring is insignificant for larger objects like molecules, cats, and galaxies. But as we zoom in on individual subatomic particles, the range of possibilities expands, forcing the location states of various quantum waves to overlap.

When that happens, particles have a slight chance of appearing where they have no business being, tunneling into regions that would otherwise require a great deal of force to enter.

One of those regions for an electron might be within the bonding-zone of a chemical reaction, welding together neighboring atoms and molecules without the boom-crash-crush of heat or pressure.

part1

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:51am

Breathtakingly Beautiful Photo Gives an Astronaut's View of an Aurora

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:45am

Researchers have discovered a new type of coexistence between algae and fungi

Researchers  have described the symbiotic relationship between fungi and algae.  The coexistence of algae and corticioid basidiomycetes, which are common in temperate forests, has been given a new name: "alcobiosis." Their work has been published in Scientific Reports.

Years ago, during field trips, researchers were repeatedly puzzled to find a layer of green algae where some of the fungal coatings on wood or bark (so-called corticioid fungi) are disturbed. They discovered that this is a close symbiosis of fungi and algae, not a lichen, though, because the fungus does not depend on its alga for nourishment.

The new term introduced by the researchers for this type of coexistence, "alcobiosis," is formed by letters from the three key words: algae, corticioid fungi and symbiosis.

In the course of several years, the team of researchers gathered a large number of samples and performed DNA sequencing of the algal and fungal partners. They discovered that the symbiosis is very common and occurs in a great many corticioid fungi across the class of agaricomycetes. Individual fungal species are usually faithful to a specific algal species from a range of algae described in various alcobioses.

Ensuing physiological measurements of algal activity in alcobioses confirmed that the algae are alive, active and engage heavily in photosynthesis, which proves that they prosper inside fungal tissue. Alcobioses bear a striking resemblance to lichens, but differ from them in that the fungal partner does not depend on its alga for nourishment.

And so the main unknown still is in what way this symbiosis is beneficial for each of the partners.

But this study shows alcobioses as a widespread phenomenon which includes a large number of algae and fungi.

During their research, the authors also discovered that the spread of alcobioses is aided by small gastropods who often feed on corticioid fungi. Their excrements contain viable cells of algae and fungi who give rise to new alcobiotic coating shortly after. This type of reproduction is similar to lichen "isidia" (i.e., specific lichen thallus structures used in vegetative reproduction). Alcobioses are clearly visible to the naked eye and it is easy to distinguish them from similar fungi that do not form this kind of relationship.

Alcobioses are common in urban areas, too. Lyomyces sambuci, pictured here, is abundant on elder bark. Credit: Institute of Botany, Czech Academy of SciencesJan Vondrák et al, Alcobiosis, an algal-fungal association on the threshold of lichenisation, Scientific Reports (2023). DOI: 10.1038/s41598-023-29384-4. www.nature.com/articles/s41598-023-29384-4

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:29am

How to stop bird flu becoming a pandemic

After avian influenza killed a girl in Cambodia last week, fears are rising about the virus’s potential to spark a human pandemic. It’s hard to say whether this will actually happen, says veterinary pathologist Thijs Kuiken. Versions of the H5N1 influenza virus have been circulating in birds for about 25 years, but the discovery of a variant that transmits between mink increases the risk that the virus could start spreading in humans. Scientists say it’s important to keep tracking the disease’s spread.... Because drugs and vaccines against H5N1 are already available, a bird flu pandemic would probably be more manageable than COVID-19.

https://www.nature.com/articles/d41586-023-00591-3?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:27am

Asteroid lost 1 million kilograms after collision with DART spacecraft

Studies reveal final moments before NASA probe crashed into an asteroid.

The asteroid that was deliberately hit with NASA’s Double Asteroid Redirection Test (DART) spacecraft last September lost one million kilograms of rock, gained a 1,000-kilometre-long d.... A detailed analysis of what happened when DART smashed into the Great-Pyramid-sized asteroid Dimorphos has revealed how successful this first test of planetary defence really was. The spacecraft hit a spot close to the asteroid’s centre and caused a large spray of rubble to fly outwards, which maximized the impact’s force and added momentum.

Last September, NASA’s Double Asteroid Redirection Test (DART) spacecraft smashed into an asteroid, deliberately altering the rock’s trajectory through space in a first test of planetary defence. Now scientists have deconstructed the collision and its aftermath — and learnt just how successful humanity’s punch at the cosmos really was.

DART, which was the size of a golf cart, collided with a Great Pyramid-sized asteroid called Dimorphos. The impact caused the asteroid’s orbit around another space rock to shrink — Dimorphos now completes an orbit 33 minutes faster than before the impact, researchers report in Nature. This means that if a dangerous asteroid were ever detected heading for Earth, a mission to smash into it would probably be able to divert it away from the planet.

https://www.nature.com/articles/d41586-023-00601-4?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 11:12am

Scientists push the boundaries of manipulating light at the submicroscopic level

A team of researchers  has shown light can be moved within a distance which is smaller than its own wavelength—a level of unprecedented precision.

Scientists have demonstrated that a beam of light can not only be confined to a spot which is 50 times smaller than its own wavelength, but that also—in a first of its kind—the spot can be moved by miniscule amounts at the point where the light is confined. The detailed findings of their theoretical study are published in the journal Optica.

Confining and controlling light on ever smaller volumes is one of the defining challenges in modern photonics; the science behind the generation, detection and manipulation of light. How tightly the light is confined determines the limits for the observability of nanoparticles, as well as the intensity and the precision of light-based devices. One example is optical tweezers. These are widely used in laboratories around the world in fields such as that of DNA research. They consist of highly focused laser beams that trap, manipulate and move particles with astounding precision. One of the limitations with standard optical tweezers is that lenses cannot focus beams on lengths much smaller than the laser beam's own wavelength, limiting the achievable precision.

By its nature, light is indeed very difficult to localize on a smaller length scale than its wavelength, a critical threshold known as the Abbe limit. However, using a sophisticated model and numerical simulation, scientists have successfully demonstrated a novel approach to localize and dynamically manipulate light at a sub-wavelength scale.

Erika Cortese et al, Real-space nanophotonic field manipulation using non-perturbative light–matter coupling, Optica (2022). DOI: 10.1364/OPTICA.473085

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 10:10am

Social animals should limit individuality to conform with the behaviour of the group, says study

Scientists  have observed that group safety was improved when animals paid attention to the behaviours of each other.

Their findings, accepted for publication in PLoS Computational Biology, reveal that simple social behavioral rules can drive conformity behaviour in groups, eroding consistent behavioural differences shown by individual animals.

Personality suppression may be a common strategy in group-living animals, and in particular, we should tend to see the behaviors of the most adventurous or shy individuals shifting towards what the majority of the group are doing.

The team modeled the behavior of a small group of animals with differing tendencies while performing risky behaviours when traveling away from a safe home site towards a foraging site. They then compared this to their behaviour while completing the same activity in a group.

The group-aware individuals spent longer in the safe space and moved more quickly to the foraging spot, making the mission less dangerous. Groups are usually made up of individuals who are different to each other in the way that they normally behave—these consistent individual differences are what determines the personality of the individual.

This study was based on fish behaviour. 

When faced with a social task,  researchers found that the fish tend to suppress their own behavior, and instead conform with what other fish in the group are doing.

 If individuals pay attention to other group members, this has an overall impact on the efficiency of the group, and demonstrates that simple social behaviors can result in the suppression of individual personalities.

.This suggests that compromise may lie at the heart of many social behaviors across the animal kingdom.

Sean A. Rands et al, Personality variation is eroded by simple social behaviours in collective foragers, PLoS Computational Biology (2023). DOI: 10.1371/journal.pcbi.1010908. journals.plos.org/ploscompbiol … journal.pcbi.1010908 On bioRxiv: DOI: 10.1101/2022.03.21.485155

Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 9:44am

'Rivers in the sky' shape African climate

East Africa is much drier than other tropical land regions, including the Amazon and Congo rainforests. The geography of East Africa was always thought to make the region dry and susceptible to drought, but the precise mechanism has been elusive until now. This research demonstrates the east to west river valleys are a crucial factor in the low annual rainfall.

Normally, when we think of valleys and water, we think of the rivers that flow along the ground. In East Africa, deep valleys, such as the Turkana Valley, channel strong winds and create invisible rivers in the sky. These invisible rivers carry millions of tons of water vapor, the key ingredient for rainfall.

New experiments show the valleys affect climate on a continental scale. It can't rain equally everywhere, and the valleys help to sustain high rainfall in the Congo basin, while leaving East Africa prone to drought.

Callum Munday et al, Valley formation aridifies East Africa and elevates Congo Basin rainfall, Nature (2023). DOI: 10.1038/s41586-022-05662-5

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Comment by Dr. Krishna Kumari Challa on March 3, 2023 at 9:31am

Satellite images show coastal algae blooms have grown larger over past two decades

A team of Earth scientists affiliated with multiple institutions has found that coastal algae blooms (also known as phytoplankton blooms) have been getting bigger over the past couple of decades. In their study, published in the journal Nature, the group analyzed satellite data supplied to them by NASA to compare the size and frequency of algae blooms along the coasts of the world's continents.

Algae blooms are accumulations of algae in a shared area atop a water source. Algae are aquatic plants that contain chlorophyll, but have no leaves, roots, stems, vascular tissue or flowers. They vary in size, from single-celled species to large strands of seaweed. They can have different colors and can inhabit either fresh or saltwater systems. Algae blooms grow larger as their food source grows, particularly nitrogen and phosphorus, both of which are supplied indirectly through human sources such as fertilizer runoff. Prior research has shown that algae blooms can serve as a food source for some sea creatures, but they can also cause problems, such as carrying and dispersing toxic material. Such toxins have been found to accumulate in ocean networks, sometimes leading to oxygen depletion, which can lead to ocean dead zones. In this new effort, the research team found evidence that algae blooms are getting larger, which suggests fertilizer runoff has been increasing.

The work involved studying satellite images obtained from NASA's Aqua satellite over the years 2003 to 2020. By comparing such blooms over time, they found them to be growing at an increasing rate of 59.2%, globally. They also found that as of 2020, the combined size of all ocean-based algae blooms was 31.47 million km², which, they note, is approximately 8.6% of total ocean surface area.

The researchers also found patterns of increase—the areas where the water temperatures were rising the fastest were the same areas where the algae blooms were growing the fastest. Additionally, they found associations between sea surface temperatures, ocean circulation and the frequency of algae blooms.

More information: Yanhui Dai et al, Coastal phytoplankton blooms expand and intensify in the 21st century, Nature (2023). DOI: 10.1038/s41586-023-05760-y

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