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Comment by Dr. Krishna Kumari Challa on September 23, 2020 at 6:07am

Evolution of radio-resistance is very complicated 

The toughest organisms on Earth, called extremophiles, can survive extreme conditions like extreme dryness (desiccation), extreme cold, space vacuum, acid, or even high-level radiation. So far, the toughest of all seems to be the bacterium Deinococcus radiodurans—able to survive doses of radiation a thousand times greater than those fatal to humans. 

How this radio-resistance could have evolved in several organisms on our planet, naturally protected from solar radiation by its magnetic field? While some scientists suggest that radio-resistance in extremophile organisms could have evolved along with other kinds of resistance, such as resistance to desiccation, a question remained: which genes are specifically involved in radio-resistance?

To find out the researchers started with the naturally non-resistant bacteria, E. coli, and exposed it to iterative cycles of high-level irradiation. After many rounds of radiation exposure and outgrowth, a few radio-resistant populations emerged. Using whole-genome sequencing, the researchers studied the genetic alterations present in each radio-resistant population and determined which mutation provided radio-resistance to the bacteria.

The study of their genetic profile highlighted three mutations responsible for radio-resistance—all in genes linked to DNA repair mechanisms. The results show that the populations of radioresistant E. coli, continued to evolve and sub-populations emerged. Surprisingly, while radio-resistance induced by the first series of ionization could mainly be associated with three mutations, the second induced hundreds of mutations including large deletions and duplications of several genes. The four populations scienitsts are evolving in this new trial have now achieved levels of radio-resistance that are approaching the levels seen with Deinococcus radiodurans. As the current trial has progressed, the genomic alterations have proven to be much more complex than anticipated.

The researchers show that more cellular metabolisms are affected (ATP synthesis, iron-sulfur cluster biogenesis, cadaverine synthesis, and reactive oxygen species response). Furthermore, this study proves that radio-resistance can develop to the level of Deinococcus radiodurans, independently to desiccation-resistance. 

As the exposition to radiation and experimental evolution continues, more data are gathered on how to induce radio-resistance in bacteria. This could one day constitute a precious toolbox of mutations to engineer radioresistant probiotics helping for example patients treated with radiotherapy, or astronauts exposed to space radiation.

 Frontiers in Microbiology, DOI: 10.3389/fmicb.2020.582590 , www.frontiersin.org/articles/1 … 2020.582590/abstract

https://phys.org/news/2020-09-evolution-radio-resistance-complicate...

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 6:26am

Solstices and equinoxes are the products of Earth's axial tilt: the degree to which the planet is tilted relative to the Sun.

The axis around which the Earth spins isn't straight up and down - it's about 23.5 degrees off. Because of that, different parts of the Earth get exposed to more or less sunlight as the planet rotates around the Sun. That's why we have seasons.

It's also why the northern and Southern Hemisphere experience seasons at opposite times: During winter in the Northern Hemisphere, the Southern Hemisphere is tilted more towards the Sun, and vice versa.

Meanwhile, Earth is also constantly rotating, which keeps its heating even - kind of like a planet-sized rotisserie chicken twisting over a spit.

The axial tilt's most dramatic effect comes during the solstices, since those are the two days when one side of the planet is tilted the farthest away from the Sun and the other is the closest. On December 21, the Northern Hemisphere receives less than nine hours of daylight, while the Southern Hemisphere receives more than 15.

https://www.sciencealert.com/the-september-equinox-is-this-tuesday-...

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 6:20am

How your brain finds the good objects

How your brain finds the good objects

In the wild, it is essential for animals to pick out good or bad objects within their visual field. Whether it be food or predator, split-second recognition and action need to be made for survival.

https://researchnews.cc/news/2629/How-your-brain-finds-the-good-obj...

The underlying mechanisms that govern this behavior in the brain has been gradually uncovered by researchers. Nowscientists have revealed how the brain controls eye movements toward the 'good objects'.

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Seismic data explains continental collision beneath Tibet

https://phys.org/news/2020-09-seismic-continental-collision-beneath...

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 6:17am

Giant spider provides promise of pain relief for irritable bowel syndrome

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 5:40am

**‘I didn’t mean to hurt you’: new research shows funnel webs don’t set out to kill humans

https://theconversation.com/i-didnt-mean-to-hurt-you-new-research-s...

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Mass Elephant Deaths in Botswana Caused By Bacteria Toxin In Waterholes

The mysterious deaths of at least 330 elephants in Botswana this year was caused by cyanobacteria-infected water, say wildlife officials. There are still many unanswered questions, including why only elephants seem to have been affected and why this mostly occurred in one region. 

https://www.bloomberg.com/news/articles/2020-09-21/botswana-says-ma...

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Are Humans Still Evolving? Find out ….

https://www.sciencealert.com/are-humans-still-evolving

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 5:25am

Defying a 150-year-old rule for phase behaviour

Frozen water can take on up to three forms at the same time when it melts: liquid, ice and gas. This principle, which states that many substances can occur in up to three phases simultaneously, was explained 150 years ago by the Gibbs phase rule. Now researchers  are defying this classical theory, with proof of a five-phase equilibrium, something that many scholars considered impossible.

Gibbs' thermodynamics rule: If we take water as an example, there is one point, with a specific temperature and pressure, where water occurs as gas, liquid and ice at the same time, the so-called triple point.

But researchers   now show that in this mixture, there is a whole series of circumstances in which four phases exist at the same time. There is even one point at which there are five coexisting phases—two too many.

 At that specific point, also called a five-phase equilibrium, a gas phase, two liquid crystal phases, and two solid phases with 'ordinary' crystals exist simultaneously. And that has never been seen before. This is the first time that the famous Gibbs rule has been broken.

The crux lies in the shape of the particles in the mixture. scientists now show that it is precisely the specific length and diameter of the particles that play a major role.

In addition to the known variables of temperature and pressure, you get two additional variables: the length of the particle in relation to its diameter, and the diameter of the particle in relation to the diameter of other particles in the solution.

V. F. D. Peters et al, Defying the Gibbs Phase Rule: Evidence for an Entropy-Driven Quintuple Point in Colloid-Polymer Mixtures, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.127803

https://phys.org/news/2020-09-defying-year-old-phase-behavior.html?...

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 5:21am

Researchers identify new type of superconductor

Until now, the history of superconducting materials has been a tale of two types: s-wave and d-wave. Now researchers have discovered a possible third type: g-wave.

Electrons in superconductors move together in what are known as Cooper pairs. This "pairing" endows superconductors with their most famous property—no electrical resistance—because, in order to generate resistance, the Cooper pairs have to be broken apart, and this takes energy.

In s-wave superconductors—generally conventional materials, such as lead, tin and mercury—the Cooper pairs are made of one electron pointing up and one pointing down, both moving head-on toward each other, with no net angular momentum. In recent decades, a new class of exotic materials has exhibited what's called d-wave superconductivity, whereby the Cooper pairs have two quanta of angular momentum.

Physicists have theorized the existence of a third type of superconductor between these two so-called "singlet" states: a p-wave superconductor, with one quanta of angular momentum and the electrons pairing with parallel rather than antiparallel spins. This spin-triplet superconductor would be a major breakthrough for quantum computing because it can be used to create Majorana fermions, a unique particle which is its own antiparticle.

For more than 20 years, one of the leading candidates for a p-wave superconductor has been strontium ruthenate (Sr2RuO4), although recent research has started to poke holes in the idea.

Researchers now  set out to determine once and for all whether strontium ruthenate is a highly desired p-wave superconductor. Using high-resolution resonant ultrasound spectroscopy, they discovered that the material is potentially an entirely new kind of superconductor altogether: g-wave.

 Thermodynamic evidence for a two-component superconducting order parameter in Sr2RuO4, DOI: 10.1038/s41567-020-1032-4 , www.nature.com/articles/s41567-020-1032-4

https://phys.org/news/2020-09-superconductor.html?utm_source=nwlett...

Comment by Dr. Krishna Kumari Challa on September 22, 2020 at 5:11am

Why there is no speed limit in the superfluid universe

Physicists  have established why objects moving through superfluid helium-3 lack a speed limit.

Helium-3 is a rare isotope of helium, in which one neutron is missing. It becomes superfluid at extremely low temperatures, enabling unusual properties such as a lack of friction for moving objects.

It was thought that the speed of objects moving through superfluid helium-3 was fundamentally limited to the critical Landau velocity, and that exceeding this speed limit would destroy the superfluid. Prior experiments in Lancaster have found that it is not a strict rule and objects can move at much greater speeds without destroying the fragile superfluid state.

Now scientists from Lancaster University have found the reason for the absence of the speed limit: exotic particles that stick to all surfaces in the superfluid.

The discovery may guide applications in quantum technology, even quantum computing, where multiple research groups already aim to make use of these unusual particles.

Superfluid helium-3 feels like vacuum to a rod moving through it, although it is a relatively dense liquid. There is no resistance, none at all.

Nature Communications (2020). DOI: 10.1038/s41467-020-18499-1

https://phys.org/news/2020-09-limit-superfluid-universe.html?utm_so...

Comment by Dr. Krishna Kumari Challa on September 21, 2020 at 10:32am

Big Wind: The Ultimate Fire Extinguisher

Comment by Dr. Krishna Kumari Challa on September 21, 2020 at 9:05am

This video shows just how easily COVID-19 could spread when people sing together

and how online singing is safe …..

Other options for safer group singing now and in the future include: singing outside or in a well-ventilated room with large open windows as this is likely to dissipate aerosols and further reduce the risk physical distancing of at least two metres while singing short performances to minimise exposure humming rather than singing during rehearsals, because we show consonants (such as “do”) generate the most aerosols singing softly (and using amplifiers) as this is likely to emit fewer aerosols using rapid test kits, if available, which would allow singers to be screened before performing assessing risk factors for individual singers based on age, chronic diseases and other risk factors for COVID-19. It is more important people at high risk of complications from COVID-19 avoid group singing while there is community transmission. Some people recommend wearing face shields while group singing. But these allow you to breathe in aerosols through the gap underneath, which may be even more likely with the powerful inhalations during singing.

https://theconversation.com/this-video-shows-just-how-easily-covid-...

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