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Comment by Dr. Krishna Kumari Challa on July 25, 2021 at 9:56am

Cockatoos   have learned to open curb-side bins — and it has global significance

https://theconversation.com/clever-cockatoos-in-southern-sydney-hav...

Comment by Dr. Krishna Kumari Challa on July 24, 2021 at 8:10am

The science of underwater swimming: How staying submerged gives Olympians the winning edge

To win swimming gold in Tokyo, swimmers not only have to generate incredible power with their arms and legs to propel themselves through the water; they also have to overcome the relentless pull of the water's drag while doing so.

Without being able to don special low-drag suits or use technologies to help them fly over the water, how can swimmers make the effect of the water's drag as small as possible?

The best athletes in this year's Olympics will do it by swimming under, rather than on top of, the water—at least as far as the rules allow.

Water is much denser than air, so you might assume swimmers would benefit from using a technique that allows them to sit high in the water, with as much of their body out of the water as possible.

But there are two problems with this strategy.

First, it costs energy to produce the forces needed to lift the body, which would be better spent propelling the swimmer forwards towards the finishing wall.

Second, when we travel on the water's surface we waste energy making waves. During fast swimming, such as in the sprint freestyle events or during starts and turns (where speeds exceed 2 meters per second, or about 7 kilometers per hour), wave generation slows the swimmer down more than any other factor. Reducing wave formation is therefore vital to swimming success.

Waves are produced as the pressure exerted by the swimmer on the water forces the water upwards and out of their path. Other pressure changes around the swimmer's body also cause waves to form behind them, and sometimes to the side.

The energy required to generate waves comes from the swimmer themselves, so a lot of the power generated by the swimmer's muscles is used in wave generation rather than moving the swimmer forwards.

But waves aren't formed when we (or fish, dolphins or whales) swim under the water, because waves only form when an object (like us) moves at the boundary between two fluids of different densities, such as water and air during swimming. And this fact hints at an intriguing solution to the drag issue.

Here, the swimmer propels themselves underwater by undulating the lower body in a wave-like manner while maintaining a rigid and streamlined upper body position with arms stretched overhead.

The amplitude of the lower body undulation increases from the hips to the feet so the "wave" produced by the body is much greater down towards the feet, creating a whip-like effect. This pushes water rapidly backwards, propelling the swimmer forwards according to Newton's law of action and reaction.

Although some aspects of underwater swimming is banned, the benefits of improving the underwater undulation technique are so great that swimmers still spend hours each week in training improving this part of the race.

https://theconversation.com/the-science-of-underwater-swimming-how-...

Comment by Dr. Krishna Kumari Challa on July 23, 2021 at 10:11am

Why delta variant is highly transmissible 

In a preprint posted 12 July¹, the researchers report that virus was first detectable in people with the Delta variant four days after exposure,compared with an average of six days among people with the original strain, suggesting that Delta replicates much faster. Individuals infected with Delta also had viral loads up to 1,260 times higher than those in people infected with the original strain.

The combination of a high number of viruses and a short incubation period makes sense as an explanation for Delta’s heightened transmissibility.

The sheer amount of virus in the respiratory tract means that superspreading events are likely to infect even more people, and that people might begin spreading the virus earlier after they become infected.

And the short incubation makes contact tracing more difficult in some countries.

Putting it all together, Delta’s really difficult to stop.

The highly contagious Delta variant of Covid-19 is expected to become the dominant strain of the virus over the coming months, according to the World Health Organization.

https://www.medrxiv.org/content/10.1101/2021.07.07.21260122v1

https://www.nature.com/articles/d41586-021-01986-w?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on July 23, 2021 at 9:28am

How newborn mammals dream the world they're entering

As a newborn mammal opens its eyes for the first time, it can already make visual sense of the world around it. But how does this happen before they have experienced sight?

A new  study suggests that, in a sense, mammals dream about the world they are about to experience before they are even born.

Scientists describe the process as waves of activity that emanate from the neonatal retina in mice before their eyes ever open.

This activity disappears soon after birth and is replaced by a more mature network of neural transmissions of visual stimuli to the brain, where information is further encoded and stored.

But how do the circuits form that allow us to perceive motion and navigate the world? It turns out we are born capable of many of these behaviors, at least in rudimentary form.

Scientists explored the origins of these waves of activity. Imaging the brains of mice soon after birth but before their eyes opened, the Yale team found that these retinal waves flow in a pattern that mimics the activity that would occur if the animal were moving forward through the environment.

This early dream-like activity makes evolutionary sense because it allows a mouse to anticipate what it will experience after opening its eyes, and be prepared to respond immediately to environmental threats.

They also investigated the cells and circuits responsible for propagating the retinal waves that mimic forward motion in neonatal mice. They found that blocking the function of starburst amacrine cells, which are cells in the retina that release neurotransmitters, prevents the waves from flowing in the direction that mimics forward motion. This in turn impairs the development of the mouse's ability to respond to visual motion after birth.

Intriguingly, within the adult retina of the mouse these same cells play a crucial role in a more sophisticated motion detection circuit that allows them to respond to environmental cues.

Mice, of course, differ from humans in their ability to quickly navigate their environment soon after birth. However, human babies are also able to immediately detect objects and identify motion, such as a finger moving across their field of vision, suggesting that their visual system was also primed before birth.

These brain circuits are self-organized at birth and some of the early teaching is already done. It's like dreaming about what you are going to see before you even open your eyes.

X. Ge el al., "Retinal waves prime visual motion detection by simulating future optic flow," Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abd0830

https://phys.org/news/2021-07-eyes-wide-newborn-mammals-world.html?...

Comment by Dr. Krishna Kumari Challa on July 23, 2021 at 9:18am

RNA breakthrough creates crops that can grow 50% more potatoes, rice

Manipulating RNA can allow plants to yield dramatically more crops, as well as increasing drought tolerance, announced a group of scientists.

In initial tests, adding a gene encoding for a protein called FTO to both rice and potato plants increased their yield by 50% in field tests. The plants grew significantly larger, produced longer root systems and were better able to tolerate drought stress. Analysis also showed that the plants had increased their rate of photosynthesis.

The change really is dramatic. What's more, it worked with almost every type of plant scientists tried it with so far, and it's a very simple modification to make.

We know that the RNA molecule reads DNA, then makes proteins to carry out tasks. But RNA doesn't simply read the DNA blueprint and carry it out blindly; the cell itself can also regulate which parts of the blueprint get expressed. It does so by placing chemical markers onto RNA to modulate which proteins are made and how many. Scientists realized that this had major implications for biology. 

They focused on a protein called FTO, the first known protein that erases chemical marks on RNA. The scientists knew it worked on RNA to affect cell growth in humans and other animals, so they tried inserting the gene for it into rice plants—and then watched in amazement as the plants took off.

The rice plants grew three times more rice under laboratory conditions. When they tried it out in real field tests, the plants grew 50% more mass and yielded 50% more rice. They grew longer roots, photosynthesized more efficiently, and could better withstand stress from drought.

The scientists repeated the experiments with potato plants, which are part of a completely different family. The results were the same.

That suggested a degree of universality that was extremely exciting.

RNA demethylation increases the yield and biomass of rice and potato plants in field trials, Nature Biotechnology, DOI: 10.1038/s41587-021-00982-9 , www.nature.com/articles/s41587-021-00982-9

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It took the scientists longer to begin to understand how this was happening. Further experiments showed that FTO started working early in the plant's development, boosting the total amount of biomass it produced.

The scientists think that FTO controls a process known as m6A, which is a key modification of RNA. In this scenario, FTO works by erasing m6A RNA to muffle some of the signals that tell plants to slow down and reduce growth. 

https://phys.org/news/2021-07-rna-breakthrough-crops-potatoes-rice....

Comment by Dr. Krishna Kumari Challa on July 22, 2021 at 8:31am

Phage-based COVID vaccines

Comment by Dr. Krishna Kumari Challa on July 22, 2021 at 8:12am

Fire tornadoes explained

The roaring Bootleg Fire burning up swaths of southwestern Oregon is the nation's largest wildfire so far this year and intense enough that it's triggering weather phenomena, including lightning, massive columns of smoke and ash clouds reaching high into the atmosphere, and even the possibility of a "fire tornado." Loretta Mickley, senior research fellow in chemistry-climate interactions at the Harvard John A. Paulson School of Engineering and Applied Sciences, has examined the interaction of wildfires and climate and published research on the likelihood that the wildfires will grow larger and more frequent in the years to come. The Gazette spoke to Mickley to better understand the causes, dangers, and expectations for the future.

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Planetary shields will buckle under stellar winds from their dying ...

Any life identified on planets orbiting white dwarf stars almost certainly evolved after the star's death, says a new study led by the University of Warwick that reveals the consequences of the intense and furious stellar winds that will batter a planet as its star is dying. The research is published in Monthly Notices of the Royal Astronomical Society, and lead author Dr. Dimitri Veras will present it today (21 July) at the online National Astronomy Meeting (NAM 2021).

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Windows 10/11 vulnerability exposes admin passwords to local users

A Twitter user has found and made public a Windows 10/11 vulnerability that exposes admin passwords to local users who can then escalate their privileges up to admin, giving them total system access. As he notes on his posts, he found that Windows Security Account Manager (SAM) data could be read by users with very limited privileges, giving them access to admin passwords. Microsoft apparently caught wind of the vulnerability and posted an Executive Summary of the issue on its Security Vulnerability page.

Comment by Dr. Krishna Kumari Challa on July 22, 2021 at 8:08am

Rounding errors could make certain stopwatches pick wrong race winners

As the Summer Olympics draw near, the world will shift its focus to photo finishes and races determined by mere fractions of a second. Obtaining such split-second measurements relies on faultlessly rounding a raw time recorded by a stopwatch or electronic timing system to a submitted time.

Researchers now found certain stopwatches commit rounding errors when converting raw times to final submitted times. They outline a series of computer simulations based on procedures for converting raw race times for display.

These researchers were inspired when they encountered the issue firsthand while volunteering at a swim meet. While helping input times into the computer, they noticed a large portion of times they inputted were rounded to either the closest half-second or full second.

Later, when the frequencies of the digit pairs were plotted, a distinct pattern emerged. They discovered that the distribution of digit pairs was statistically inconsistent with the hypothesis that each digit pair was equally likely, as one would expect from stopwatches.

Stopwatches and electronic timing systems use quartz oscillators to measure time intervals, with each oscillation calculated as 0.0001 seconds. These times are then processed for display to 0.01 seconds, for example, to the public at a sporting venue.

When the researchers  processed raw times through the standard display routine, the uniform distribution disappeared. Most times were correctly displayed.

Where rounding errors occurred, they usually resulted in changes of one one-hundredth of a second. One raw time of 28.3194 was converted to a displayed time of 28.21.

The researchers collected more than 30,000 race times from swimming competitions and will investigate if anomalous timing patterns appear in the collection, which would suggest the potential for rounding errors in major sporting events.

David A. Faux et al, The floating point: Rounding error in timing devices, American Journal of Physics (2021). DOI: 10.1119/10.0003919

https://phys.org/news/2021-07-rounding-errors-stopwatches-wrong-win...

Comment by Dr. Krishna Kumari Challa on July 22, 2021 at 8:01am

Study finds calcium precisely directs blood flow in the brain

Unlike the rest of the body, there is not enough real estate in the brain for stored energy. Instead, the brain relies on the hundreds of miles of blood vessels within it to supply fresh energy via the blood. Yet, how the brain expresses a need for more energy during increased activity and then directs its blood supply to specific hot spots was, until now, poorly understood.

Now,  researchers have shown how the brain communicates to blood vessels when in need of energy, and how these blood vessels respond by relaxing or constricting to direct blood flow to specific brain regions.

If the brain does not get blood to where it needs it when it needs it, the neurons become stressed, and over time they deteriorate ultimately leading to cognitive decline and memory problems.

Large arteries feed medium-sized vessels known as arterioles that then feed even tinier capillaries—so small that only a single blood cell can pass through at once. In a 2017 Nature Neuroscience paper, the researchers showed that electrical pulses coursing through the capillaries direct blood flow from the medium-sized arterioles supplying large regions of the brain. For this latest paper, the team studied the fine-tuning of blood as it flows through the capillaries to precisely regulate energy supply to tiny regions in the brain.

There seem to be two mechanisms working in tandem to ensure that energy in the form of blood makes it to specific regions of the brain: one broad and the other precise. The first electrical mechanism is like a crude sledgehammer approach to get more blood to the general vicinity of the increased brain activity by controlling the medium-sized arterioles, and then capillary calcium signals ensure exquisite fine-tuning to make sure the blood gets to exactly the right place at the right time through the tiny capillaries.

"Local IP3 receptor–mediated Ca2+ signals compound to direct blood flow in brain capillaries" Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abh0101

https://medicalxpress.com/news/2021-07-calcium-precisely-blood-brai...

Comment by Dr. Krishna Kumari Challa on July 22, 2021 at 7:56am

Microbially produced fibers: Stronger than steel, tougher than Kevlar

Spider silk is said to be one of the strongest, toughest materials on the Earth. Now engineers  have designed amyloid silk hybrid proteins and produced them in engineered bacteria. The resulting fibers are stronger and tougher than some natural spider silks.

The artificial silk—dubbed "polymeric amyloid" fiber—was not technically produced by researchers, but by bacteria that were genetically engineered in the lab.

Jingyao Li et al, Microbially Synthesized Polymeric Amyloid Fiber Promotes β-Nanocrystal Formation and Displays Gigapascal Tensile Strength, ACS Nano (2021). DOI: 10.1021/acsnano.1c02944

https://phys.org/news/2021-07-microbially-fibers-stronger-steel-tou...

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