Comment

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:37am

Data reveal possible reason some exoplanets are shrinking

A new study could explain the "missing" exoplanets between super-Earths and sub-Neptunes.

Some exoplanets seem to be losing their atmospheres and shrinking. In a new study using NASA's retired Kepler Space Telescope, astronomers find evidence of a possible cause: The cores of these planets are pushing away their atmospheres from the inside out.

The study is published in The Astronomical Journal.

Exoplanets (planets outside our solar system) come in a variety of sizes, from small, rocky planets to colossal gas giants. In the middle lie rocky super-Earths and larger sub-Neptunes with puffy atmospheres. But there's a conspicuous absence—a "size gap"—of planets that fall between 1.5 to 2 times the size of Earth (or in between super-Earths and sub-Neptunes) that scientists have been working to better understand.

Scientists have now confirmed the detection of over 5,000 exoplanets, but there are fewer planets than expected with a diameter between 1.5 and 2 times that of Earth. Exoplanet scientists have enough data now to say that this gap is not a fluke. There's something going on that impedes planets from reaching and/or staying at this size.

Researchers think that this gap could be explained by certain sub-Neptunes losing their atmospheres over time. This loss would happen if the planet doesn't have enough mass, and therefore gravitational force, to hold onto its atmosphere. So sub-Neptunes that aren't massive enough would shrink to about the size of super-Earths, leaving the gap between the two sizes of planets.

But exactly how these planets are losing their atmospheres has remained a mystery. Scientists have settled on two likely mechanisms: One is called core-powered mass loss; and the other, photoevaporation. The new study has uncovered new evidence supporting the first.

 Jessie L. Christiansen et al, Scaling K2. VII. Evidence For a High Occurrence Rate of Hot Sub-Neptunes at Intermediate Ages, The Astronomical Journal (2023). DOI: 10.3847/1538-3881/acf9f9

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:34am

Exoplanet Types: Worlds Beyond Our Solar System

Comment by Dr. Krishna Kumari Challa on November 15, 2023 at 9:15am

Our Galaxy's Heart Is Pulsing With a Mysterious Signal

Compared to some other galaxies out there, the supermassive black hole at the heart of the Milky Way isn't a particularly active one. It's not guzzling down scads of material, and it's not blasting giant jets of plasma into space. Even a relatively peaceful supermassive black hole, however, is a wild, savage beast, and our own – named Sagittarius A* – has been recorded doing some pretty strange things. And now there's a new one: astrophysicists Gustavo Magallanes-Guijón and Sergio Mendoza of National Autonomous University of Mexico have recorded it sort of… pulsing. Every 76 minutes, like clockwork, the gamma-ray flux of Sgr A fluctuates. This, the researchers say, is similar in periodicity to changes in the black hole's radio and X-ray emission too, suggesting an orbital motion of something whirling madly around the black hole.

https://arxiv.org/abs/2311.05875

Comment by Dr. Krishna Kumari Challa on November 15, 2023 at 9:08am

All fireworks, including the green ones, are bad ! Did you know that Deepavali fireworks cause more distress than happiness? So we celebrate Diwali without any fireworks! All these years I never ever touched even a single one. We have been celebrating  Deepavali with fun and happiness minus fireworks for the past few years. Before somebody asks me 'How can there be fun without fireworks?', I want to add I had fun because I didn't contribute to the pollution. I didn't send out a toxic concoction into the atmosphere that rains down heavily into lakes, rivers, seas, fields and houses. I am not responsible for someone developing hypothyroidism, anemia or cancer. And I am extremely happy because of this! Fireworks get their flamboyance from a variety of chemicals, many of which are toxic to humans. From the gunpowder that fuels their flight to the metallic compounds that colour their explosions, fireworks often contain carcinogenic or hormone-disrupting substances that can seep into soil and water, not to mention the lung-clogging smoke they release and plastic debris they scatter. Almost all the major cities in India that have measured Deepavali festival-raised pollution levels recently sounded alarm bells. Some people justify their acts of using fireworks by saying that these harmful gases released into the atmosphere actually kill mosquitoes and other harmful insects! But these insects might already have developed resistance to these chemicals. Moreover, if they are harmful to some living beings, they would equally be harmful to the other ones (human beings) too! First the ever evolving fireworks tempt you and make you buy them at sky-rocketing prices causing distress to your earning loved ones. Fire accidents are quite common during this festival. The flying fire bits also get into unprotected eyes and burn eye parts, especially the cornea leading to blindness. Apart from causing agony to the animal life, the loud noises also increase hearing distress and the toxic smoke released into the atmosphere can get lodged in people's lungs and enhance asthmatic symptoms and severe breathing problems in human beings. Anybody considering him/her-self environmentally conscious and responsible will never go anywhere near these fireworks as they pose a serious environmental and health danger from heavy metals and other toxic firework fallout. So celebrate Diwali without fireworks like we do. 

Comment by Dr. Krishna Kumari Challa on November 14, 2023 at 1:30pm

Mind-Altering Cat Parasite May Trigger Frailty in Older People

An infamous parasite primarily carried by cats, Toxoplasma gondii, could be responsible for increased frailty in older adults, a new study reveals.

The discovery, made by an international team of researchers, adds to what we already know about T. gondii: that it can cause flu-like symptoms in many, and more serious issues such as seizures in people with weaker immune systems. "We often think of T. gondii infection as relatively asymptomatic, but this study highlights that for some people it may have significant health consequences later on.

The research team suspected that the parasite may be one of the causes of 'inflammaging', or persistent age-related inflammation that contributes to frailty. Blood tests from 601 Spanish and Portuguese adults aged over 65 were analyzed for measures of frailty, including unintentional weight loss, tiredness, and loss of mental sharpness. While there wasn't an association found between T. gondii infections and frailty, among those who had been infected by T. gondii, people who produced a higher number of antibodies to fight it were more likely to show signs of being frail. To put it another way, there are signs of a link between a more severe immune reaction to this parasite, and a greater likelihood of being more frail in old age. It's not enough to prove cause and effect, but it seems there might be something going on. On the inflammaging front, those with a stronger response to T. gondii (perhaps through a more widespread infection, or multiple infections) also had higher levels of certain biomarkers of inflammation, suggesting another potential link there.

Considering infection rates for T. gondii rise as people get older, and that it can lie dormant and undetected in a human body for several decades, the researchers say we need to be even more careful when it comes to avoiding infection. That can come through exposure to T. gondii eggs (in a cat's litter box, for example, or water that they've contaminated), or through eating undercooked meat that's been infected by the parasite. Keeping cats indoors and avoiding strays can help too.

https://academic.oup.com/biomedgerontology/advance-article/doi/10.1...

Comment by Dr. Krishna Kumari Challa on November 14, 2023 at 1:22pm

The Remains of an Ancient Planet Lie Deep Within Earth

Comment by Dr. Krishna Kumari Challa on November 14, 2023 at 1:03pm

Physicists trap electrons in a 3D crystal for the first time

 Electrons move through a conducting material like commuters at the height of Manhattan rush hour. The charged particles may jostle and bump against each other, but for the most part they’re unconcerned with other electrons as they hurtle forward, each with their own energy.

But when a material’s electrons are trapped together, they can settle into the exact same energy state and start to behave as one. This collective, zombie-like state is what’s known in physics as an electronic “flat band,” and scientists predict that when electrons are in this state they can start to feel the quantum effects of other electrons and act in coordinated, quantum ways. Then, exotic behavior such as superconductivity and unique forms of magnetism may emerge.

Now, physicists have successfully trapped electrons in a pure crystal. It is the first time that scientists have achieved an electronic flat band in a three-dimensional material. With some chemical manipulation, the researchers also showed they could transform the crystal into a superconductor — a material that conducts electricity with zero resistance.

The electrons’ trapped state is possible thanks to the crystal’s atomic geometry. The crystal, which the physicists synthesized, has an arrangement of atoms that resembles the woven patterns in “kagome,” the Japanese art of basket-weaving. In this specific geometry, the researchers found that rather than jumping between atoms, electrons were “caged,” and settled into the same band of energy.

The researchers say that this flat-band state can be realized with virtually any combination of atoms — as long as they are arranged in this kagome-inspired 3D geometry. The results, published in Nature, provide a new way for scientists to explore rare electronic states in three-dimensional materials. These materials might someday be optimized to enable ultraefficient power lines, supercomputing quantum bits, and faster, smarter electronic devices.

https://news.mit.edu/2023/physicists-trap-electrons-3d-crystal-firs...

Comment by Dr. Krishna Kumari Challa on November 14, 2023 at 11:42am

Forests with multiple tree species are 70% more effective as carbon sinks than monoculture forests, study finds

To slow the effects of climate change, conserve biodiversity, and meet the sustainable development goals, replanting trees is vital. Restored forests store carbon within the forest's soil, shrubs, and trees. Mixed forests are especially effective at carbon storage, as different species with complementary traits can increase overall carbon storage.

Compared to single-species forests, mixed forests are also more resilient to pests, diseases, and climatic disturbances, which increases their long-term carbon storage potential. The delivery of other ecosystem services is also greater in mixed species forests, and they support higher levels of biodiversity.

Although the benefits of diverse forest systems are well known, many countries' restoration commitments are focused on establishing monoculture plantations. Given this practice, an international team of scientists has compared carbon stocks in mixed planted forests to carbon stocks in commercial and best-performing monocultures, as well as the average of monocultures.

Diverse planted forests store more carbon than monocultures—upwards of 70%. Researchers also found the greatest increase in carbon storage relative to monocultures in four-species mixtures.

The mixed planted forests assessed in the study ranged in species richness from two to six species. In the data set the scientists worked with, four-species mixtures were the most effective carbon sinks. One such mix was made up from different broadleaf trees. Mixes with two species also had greater above-ground carbon stocks than monocultures and stored up to 35% more carbon. 

Accordingly, the researchers were able to show that diversification of forests enhances carbon storage. Altogether, above-ground carbon stocks in mixed forests were 70% higher than in the average monoculture. The researchers also found that mixed forests had 77% higher carbon stocks than commercial monocultures, made up of species bred to be particularly high yielding.

Young mixed planted forests store more carbon than monocultures—a meta-analysis, Frontiers in Forests and Global Change (2023). DOI: 10.3389/ffgc.2023.1226514

Comment by Dr. Krishna Kumari Challa on November 13, 2023 at 11:49am

Each of Your Nostrils Smells The World Uniquely, Study Reveals

It's not immediately noticeable to us, but our two nostrils are actually working independently in some ways and appear to have their own separate sense of smell.

That's the conclusion of a new study from researchers in the US that could teach us much more about the brain and how senses are processed. The findings build on earlier studies in animals and humans, indicating that our brains might be capable of processing each nostril's input individually as well as synthesizing them into one complete whole.

To look more closely at smelling in stereo, the researchers from the University of Pennsylvania, the Barrow Neurological Institute, and Ohio State University enlisted the help of 10 epilepsy patients who had already had electrodes implanted in their brains.

One of three different scents, as well as a control consisting of pure air, was puffed into either nostril or both together in each trial. After several seconds, the subject was asked to identify the smell, then state which nostril they used to detect it - left, right, or both. Meanwhile, the researchers collected data on the brain's response via the electrodes.

The team made a number of interesting observations. For example, when the same smell was presented to each nostril in turn, the resulting brain activity was similar, but not identical, suggesting some independence.

What's more, smelling through two nostrils together created two distinct bursts of activity. Though the time delay between them was very short, it was there, and the researchers suggest that this again points to the nostrils not always being in unison. Two nostrils were better than one when it came to identifying odors and identifying them more quickly, which hints that there's definitely some benefit to having two nostrils rather than one – as with eyes and ears. The analysis concentrated on the piriform cortex (PC) brain region, where the sense of smell is handled and interpreted. As we already know, our different senses are closely interconnected too, which means the findings may have implications beyond smell.

https://www.cell.com/current-biology/fulltext/S0960-9822(23)01379-9

Comment by Dr. Krishna Kumari Challa on November 13, 2023 at 11:44am

Liver cells age differently depending on where they are in the organ

 People age at different rates. But what about inside of a living body? Do all cells age in the same way? And does the location of a cell in the organ make a difference to the ageing process? Researchers  have now shown in the liver of mice that liver cells age differently depending on where they are located in the organ.

The liver is largely made up of a single type of cell, the hepatocyte. Depending on where they are in the liver, they have different roles. Near the portal vein, where fresh, oxygen-rich blood enters the liver, hepatocytes use the oxygen to process fats in their mitochondria and produce energy. In contrast, carbohydrates are broken down in the less oxygen-rich regions of the liver. "In the liver, the position of the hepatocyte in the organ plays a crucial role. That's why the liver was the perfect model for us to investigate whether location also makes a difference in ageing.

The location of the liver cells has a strong influence on the ageing process. In the region of the liver where the liver cells use oxygen for energy production in their mitochondria, this process deteriorates significantly with age. In the central, oxygen-deprived area of the liver, however, the researchers found no change in the mitochondria, but a change in the cells' fat metabolism.

It is important where a cell ages. They age differently depending on where they are located and what their function is, according to these researchers. 

https://www.mpg.de/21085057/1109-balt-location-location-location-15...

• ‹ Previous
• 1
• …
• 317
• 318
• 319
• 320
• 321
• …
• 1083
• Next ›
• Page