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Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 1:32pm

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 1:30pm

The squid and its giant nerve fibre Part 1

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 1:07pm

NASA Testing Electric 'Air Taxi' Prototype Designed to Carry Passengers in The Sky

NASA is commonly thought of as America's space agency, but its name also emphasizes another research area. The National Aeronautics and Space Administration is also America's civilian aerospace research organization. 

Electric Vertical Take-Off and Landing Aircraft

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 1:01pm

Hundreds of Medical Journals Just United Together to Issue a Brutally Frank Warning

Global warming is already affecting people's health so much that emergency action on climate change cannot be put on hold while the world deals with the COVID-19 pandemic, medical journals across the globe warned on Monday.

Health is already being harmed by global temperature increases and the destruction of the natural world," read an editorial published in more than 220 leading journals ahead of the COP26 climate summit in November.

Since the pre-industrial era, temperatures have risen around 1.1 degrees Celsius.

The editorial, written by the editors-in-chief of over a dozen journals including the Lancet, the East African Medical Journal, Brazil's Revista de Saude Publica and the International Nursing Review, said this had caused a plethora of health problems.

"In the past 20 years, heat-related mortality among people older than 65 years has increased by more than 50 percent," it read.

"Higher temperatures have brought increased dehydration and renal function loss, dermatological malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary morbidity and mortality."

It also pointed to the decline in agricultural production, "hampering efforts to reduce undernutrition".

These effects, which hit those most vulnerable like minorities, children, and poorer communities hardest, are just the beginning, it warned.

https://www.bmj.com/content/374/bmj.n1734

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 12:47pm

New Mathematical Solutions to An Old Problem in Astronomy

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 12:38pm

Why are planets round?

 Earth is round. So are other planets in the solar system.

When you drop anything, gravity causes it to fall directly toward the center of the Earth, at least until it hits the ground. Gravity is a force that is caused by nearly everything that has mass. Mass is a measure of how much material there is in anything. It could be in the form of rocks, water, metal, people – anything. Everything material has mass, and therefore everything causes gravity. Gravity always pulls toward the center of mass.

The Earth and all planets are round because when the planets formed, they were composed of molten material – essentially very hot liquid. Since gravity always points toward the center of a mass, it squeezed the stuff the Earth is made of equally in all directions and formed a ball. When the Earth cooled down and became a solid, it was a round ball. If the Earth didn’t spin, then it would have been a perfectly round planet. Scientists call something that is perfectly round in all directions a “sphere.”

The gas cloud that the Earth was made from was slowly rotating in one direction around an axis. The top and bottom of this axis are the north and south poles of Earth.

If you ever played on a merry-go-round, you know that the spinning merry-go-round tends to throw you off. The faster it spins, the harder it is to stay on. This tendency to be flung off is called centrifugal force and pushes the mass on the equator outward. This makes the planet bulge at the equator.

The faster the spin, the more unround it becomes. Then, when it cools and hardens, it retains that shape. If a molten planet starts off spinning faster, it would be less round and have a bigger bulge.

The planet Saturn is very oblate – non-spherical – because it rotates very fast. Because of gravity, all planets are round, and because they rotate at different rates, some have fatter equators than their poles. So the shape of the planet and the speed and direction that it rotates depends on the initial condition of the material out of which it forms.

https://theconversation.com/why-are-planets-round-164903?utm_medium...

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 12:24pm

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 12:07pm

 Fridge-free COVID-19 vaccines  grown in plants and bacteria

Nanoengineers have developed COVID-19 vaccine candidates that can take the heat. Their key ingredients? Viruses from plants or bacteria.

The new fridge-free COVID-19 vaccines are still in the early stage of development. In mice, the vaccine candidates triggered high production of neutralizing antibodies against SARS-CoV-2, the virus that causes COVID-19. If they prove to be safe and effective in people, the vaccines could be a big game changer for global distribution efforts, including those in rural areas or resource-poor communities.

What's exciting about this vaccine technology is that is thermally stable, so it could easily reach places where setting up ultra-low temperature freezers, or having trucks drive around with these freezers, is not going to be possible.

The researchers created two COVID-19 vaccine candidates. One is made from a plant virus, called cowpea mosaic virus. The other is made from a bacterial virus, or bacteriophage, called Q beta.

Both vaccines were made using similar recipes. The researchers used cowpea plants and E. coli bacteria to grow millions of copies of the plant virus and bacteriophage, respectively, in the form of ball-shaped nanoparticles. The researchers harvested these nanoparticles and then attached a small piece of the SARS-CoV-2 spike protein to the surface. The finished products look like an infectious virus so the immune system can recognize them, but they are not infectious in animals and humans. The small piece of the spike protein attached to the surface is what stimulates the body to generate an immune response against the coronavirus.

The researchers note several advantages of using plant viruses and bacteriophages to make their vaccines. For one, they can be easy and inexpensive to produce at large scales.

Another big advantage is that the plant virus and bacteriophage nanoparticles are extremely stable at high temperatures. As a result, the vaccines can be stored and shipped without needing to be kept cold. 

Trivalent subunit vaccine candidates for COVID-19 and their delivery devices, Journal of the American Chemical Society (2021). DOI: 10.1021/jacs.1c06600

https://phys.org/news/2021-09-fridge-free-covid-vaccines-grown-bact...

Comment by Dr. Krishna Kumari Challa on September 8, 2021 at 11:30am

Cavendish Gravity Experiment

A qualitative demonstration of universal gravitation using a torsion balance.

The Cavendish Experiment Explained

Comment by Dr. Krishna Kumari Challa on September 7, 2021 at 8:52am

Sport science: How do swimmers control their front crawl swimming velocity?

A research team  has reviewed the hydrodynamics literature related to swimming. They identified certain biomechanical aspects, including the relationship between velocity and drag forces, that are not completely understood. This work may help direct future research that could improve the performance of competitive swimmers.

The recent Tokyo Olympics provided impressive feats of speed in the pool, with elite athletes setting many new Olympic and World records. What viewers might not realize, however, is the complexity of the science underlying the sometimes split-second difference between winning a gold medal and going home empty-handed. Biomechanics, the study of motion of the body, and hydrodynamics, the area of physics dealing with fluid flows, contain many questions that remain poorly understood—and swimming fits right at the intersection of these topics. For swimmers who participate in races, even a tiny advance in knowledge can led to a competitive edge.

Now, a team of researchers  has drawn together research on front crawl swimming biomechanics, focusing on propulsive and resistive forces at different swimming velocities, to form a more complete picture of the relationships between the critical variables. New knowledge of swimming energetics and fluid mechanics has improved our understanding of factors that determine swimming performance.

One of the most important relationships to understand is how resistive forces, like drag when moving through the water, depend on the speed of the swimmer. The researchers looked at recent studies that indicated the resistive force increases in proportion to the cube of the velocity. To compensate, swimmers may try to increase their stroke frequency. However, this has limitations. Researchers inferred from experimental and simulation studies that there is a maximum frequency beyond which swimmers cannot further increase swimming velocity due to a change in the angle of attack of the hand that reduces its propulsive force. The different balance of forces at different swimming speeds also means that optimal technique may differ between long-distance and short-distance swimming.

The team also identified conflicting evidence over the effectiveness of kicking for increasing the speed of high-velocity front crawl. This indicates an opportunity to further optimize competitive swimming technique if future research can further unpack the relevant hydrodynamic factors.

The researchers found that certain simplified models of swimming often break down when trying to model more realistic conditions. For example, swimmers are not simply 'pushing' or 'pulling' the water to increase their velocity, as some textbooks frame it. This is because the increase in the negative pressure acting on the dorsal side of the hand is crucial for increasing propulsion. Therefore, teaching the proper technique is important, even for phases considered to be non-propulsive.

Hideki Takagi et al, How do swimmers control their front crawl swimming velocity? Current knowledge and gaps from hydrodynamic perspectives, Sports Biomechanics (2021). DOI: 10.1080/14763141.2021.1959946

https://phys.org/news/2021-09-swimmers-front-velocity.html?utm_sour...

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