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Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 8:19am

Violent supernovae 'triggered at least two Earth extinctions,' study suggests

At least two mass extinction events in Earth's history were likely caused by the "devastating" effects of nearby supernova explosions, a new study suggests.

Researchers note that   these super-powerful blasts—caused by the death of a massive star—may have previously stripped our planet's atmosphere of its ozone, sparked acid rain and exposed life to harmful ultraviolet radiation from the sun.

They think a supernova explosion close to Earth could be to blame for both the late Devonian and Ordovician extinction events, which occurred 372 and 445 million years ago respectively.

The Ordovician extinction killed 60% of marine invertebrates at a time when life was largely confined to the sea, while the late Devonian wiped out around 70% of all species and led to huge changes in the kind of fish that existed in our ancient seas and lakes.

Past research has failed to identify a clear cause for either event, although they are thought to have been linked to the depletion of Earth's ozone layer, which could have been triggered by a supernova.

The new study, published in Monthly Notices of the Royal Astronomical Society, found that the rate supernovae occur near to our planet is consistent with the timings of both mass extinctions.

The authors say it is a "a great illustration for how massive stars can act as both creators and destructors of life."

That's because supernovae are also known to spread the heavy elements that help form and support life across the universe.

Supernovae occur when massive stars reach the end of their lives, run out of fuel, cool off, and then collapse under the pressure of gravity. The explosions are the biggest humans have ever seen.

Supernova explosions bring heavy chemical elements into the interstellar medium, which are then used to form new stars and planets.

But if a planet, including the Earth, is located too close to this kind of event, this can have devastating effects.

Supernova explosions are some of the most energetic explosions in the universe.

"If a massive star were to explode as a supernova close to the Earth, the results would be devastating for life on Earth. This research suggests that this may have already happened", they add.

The researchers came to their conclusion after carrying out a "census" of massive stars within a kiloparsec (around 3,260 light-years) of the sun.

Alexis L. Quintana et al, A census of OB stars within 1 kpc and the star formation and core collapse supernova rates of the Milky Way, Monthly Notices of the Royal Astronomical Societyacademic.oup.com/mnras/article … 0.1093/mnras/staf083 . On arXiv (2025). DOI: 10.48550/arxiv.2503.08286

Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 8:07am

They tried out three different delivery viruses and found that a retrovirus achieved the most efficient rate of conversion. Reducing the density of cells grown in the dish also helped to improve the overall yield of motor neurons. This optimized process, which takes about two weeks in mouse cells, achieved a yield of more than 1,000%.

Proliferation history and transcription factor levels drive direct conversion to motor neurons, Cell Systems (2025). DOI: 10.1016/j.cels.2025.101205. www.cell.com/cell-systems/full … 2405-4712(25)00038-9

Compact transcription factor cassettes generate functional, engraftable motor neurons by direct conversion, Cell Systems (2025). DOI: 10.1016/j.cels.2025.101206. www.cell.com/cell-systems/full … 2405-4712(25)00039-0

Part 2

Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 8:07am

Researchers turn skin cells directly into neurons for cell therapy

Converting one type of cell to another—for example, a skin cell to a neuron—can be done through a process that requires the skin cell to be induced into a pluripotent stem cell, then differentiated into a neuron. Researchers  have now devised a simplified process that bypasses the stem cell stage, converting a skin cell directly into a neuron.

Working with mouse cells, the researchers developed a conversion method that is highly efficient and can produce more than 10 neurons from a single skin cell. If replicated in human cells, this approach could enable the generation of large quantities of motor neurons, which could potentially be used to treat patients with spinal cord injuries or diseases that impair mobility.

As a first step toward developing these cells as a therapy, the researchers showed that they could generate motor neurons and engraft them into the brains of mice, where they integrated with host tissue.

Previously scientists in Japan showed that by delivering four transcription factors to skin cells, they could coax them to become induced pluripotent stem cells (iPSCs). Similar to embryonic stem cells, iPSCs can be differentiated into many other cell types. This technique works well, but it takes several weeks, and many of the cells don't end up fully transitioning to mature cell types.

Oftentimes, one of the challenges in reprogramming is that cells can get stuck in intermediate states. So scientists are trying direct conversion, where instead of going through an iPSC intermediate, they are going directly from a somatic cell to a motor neuron.

They have demonstrated this type of direct conversion before, but with very low yields—fewer than 1%. 

In the first of the new Cell Systems papers,  scientists now reported a way to streamline the process so that skin cells can be converted to motor neurons using just three transcription factors, plus the two genes that drive cells into a highly proliferative state.

The researchers also developed a slightly different combination of transcription factors that allowed them to perform the same direct conversion using human cells, but with a lower efficiency rate—between 10 and 30%, the researchers estimate. This process takes about five weeks, which is slightly faster than converting the cells to iPSCs first and then turning them into neurons.

Once the researchers identified the optimal combination of genes to deliver, they began working on the best ways to deliver them, which was the focus of the second  Cell Systems paper.

Part 1

Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 7:09am

Long-distance neural connections are comparable to those connecting computers in distant countries
To design the CHARM model, the researchers started with a paradigm of analysis of brain dynamics that we could compare to the Internet. In certain scenarios, such as risk situations, neurons distributed in different brain regions, both close to and far from each other, are joined by different connections. These connections enable pooling the information processing power of all the neurons in the network.

Thus, although groups of neurons located in different brain regions have a limited capacity to transmit information, when they pool their resources in a network, they attain far greater processing power. This paradigm has gained strength over the past decade, as opposed to the traditional approach whereby neural regions only function in a localized manner.
In a critical state, the efficiency of long-distance neural connections is enhanced
The researchers have found that the efficiency of long-distance connections is enhanced when the brain is dominated by critical dynamics, which lead it to a state of transition between order and chaos.
We could assimilate this state to a transitional phase like the process whereby water becomes ice. At this critical point, the brain has exacerbated properties, the researchers point out.
The CHARM model has enabled ascertaining precisely the functions of these long-distance connections in this or other states, for the first time integrating the principles of quantum mechanics into a system of computational brain analysis.
By adopting the Schrödinger equation we can model these interactions with a degree of precision that was previously beyond our reach.
The research findings can also have numerous applications for improving the diagnosis and treatment of various neurological diseases, such as schizophrenia or depression. Long-distance neuronal connection dysfunctions are key to understanding the origin of these diseases.

Moreover, the study opens the door to new lines of research in the field of artificial intelligence (AI). Currently, artificial neural networks are based on a localized, non-distributed model. In the future, the possible application of the distributed paradigm to AI could multiply its current capabilities, although many technical difficulties must still be overcome to enable this.

 Gustavo Deco et al, Complex harmonics reveal low-dimensional manifolds of critical brain dynamics, Physical Review E (2025). DOI: 10.1103/PhysRevE.111.014410

Part 2

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Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 7:06am

How the brain makes decisions more quickly than computers in risky situations

Research inspired by the principles of quantum mechanics, researchers from Pompeu Fabra University (UPF) and the University of Oxford reveal new findings to understand why the human brain is able to make decisions quicker than the world's most powerful computer in the face of a critical risk situation. The human brain has this capacity despite the fact that neurons are much slower at transmitting information than microchips, which raises numerous unknown factors in the field of neuroscience.

The research is published in the journal Physical Review E.

It should be borne in mind that in many other circumstances, the human brain is not quicker than technological devices. For example, a computer or calculator can resolve mathematical operations far faster than a person. So, why is it that in critical situations—for example, when having to make an urgent decision at the wheel of a car—the human brain can surpass machines?

Most accurate computational model yet to analyze connections between farthest neurons

This recent research clarifies this matter thanks to the design of a new model of brain computational analysis, called CHARM (Complex Harmonics Decomposition). It is the most accurate model to date for examining the functions of long-distance brain connections, which link neurons that are far apart and play a fundamental role in the brain dynamics that are activated when making critical decisions. It is also the first model to apply quantum mechanics as an instrument for analyzing the brain.

The  researchers describe this model in their study. 

Part 1

Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 6:57am

Watching nature scenes can reduce pain, neuroimaging study shows

A new neuroimaging study has revealed that viewing nature can help ease how people experience pain, by reducing the brain activity linked to pain perception.

Published in the journal Nature Communications  the research offers a promising foundation for new types of non-pharmacological pain treatments. The paper is titled "Nature exposure induces analgesic effects by acting on nociception-related neural processing."

Using an fMRI scanner, researchers monitored the brain activity of 49 participants as they received pain delivered through a series of small electric shocks. When they were watching videos of a natural scene compared to a city or an indoor office, participants not only reported feeling less pain, but scans showed the specific brain responses associated with processing pain changed too.

The study used advanced machine-learning to analyze the brain networks related to pain processing. The team discovered that the raw sensory signals the brain receives when something hurts were reduced when watching a carefully designed, high-quality, virtual nature scene.

The study confirmed previous findings that suggest nature can reduce subjective reports of pain, and also marks the first clear demonstration of how natural environments influence the brain, helping to buffer against unpleasant experiences.

Nature exposure induces analgesic effects by acting on nociception-related neural processing', Nature Communications (2025). DOI: 10.1038/s41467-025-56870-2

Comment by Dr. Krishna Kumari Challa on March 14, 2025 at 6:49am

Restored grasslands need 75+ years for full biodiversity recovery, study finds

Recovered grasslands need more than 75 years of continuous management to regain their biodiversity because specialized pollinators are slow to return. This finding underscores the importance of preserving old grasslands as reservoirs of biodiversity, even if it is just as ski slopes.

Grasslands worldwide are rapidly disappearing due to land-use conversion and abandonment, leading to a well-documented loss of grassland biodiversity. Restoring abandoned grasslands by removing woody vegetation and resuming traditional land management practices has positive effects on biodiversity.

However, it is also known that this diversity lags behind that of old grasslands that have been under continued management for up to several millennia. The reasons for this are not really clear and satisfying solutions have not been proposed, say the experts.

The results of a study   published in the Journal of Applied Ecology paint a consistent picture. It takes 75 years of continuous management for the plant diversity in recovered grasslands to finally reach levels comparable to ancient grasslands.

However, that's still not enough for the pollinator community. Even after 75 years, pollinators are still less specialized and less successful at pollinating the plants, although the community continuously shifts towards higher specialization and successful pollination as grasslands get older.

The finding shows that once valuable old grasslands are lost, their restoration cannot be achieved quickly.

Long-term management is required for the recovery of pollination networks and function in restored grasslands, Journal of Applied Ecology (2025). DOI: 10.1111/1365-2664.70017

Comment by Dr. Krishna Kumari Challa on March 13, 2025 at 12:39pm

128 New Moons Found Orbiting Saturn

The race between Jupiter and Saturn for the most moons in the Solar System may have just finally come screeching to a halt.

A team of scientists has found a whopping 128 previously unknown moons hanging around Saturn, in a discovery officially recognized by the International Astronomical Union. This brings the planet's total number of known moons to 274, leaving Jupiter, with its mere 95 moons, in the dust.

https://arxiv.org/abs/2503.07081

Comment by Dr. Krishna Kumari Challa on March 13, 2025 at 9:32am

Mosquito pain receptors found to be less sensitive during extreme heat, which could nullify some natural bug sprays

Hotter temperatures may render natural insect repellents less effective against mosquitoes, according to a new study. Researchers found that a pain receptor called TRPA1 becomes less sensitive in mosquitoes when exposed to heat, meaning that the chemical cues that typically trigger insect avoidance behaviors are prevented from activating as strongly.

TRPA1, also known as the "wasabi receptor," helps animals detect noxious heat and harmful chemicals. In humans, this receptor can induce eye and skin irritation. In mosquitoes, it influences which hosts the insects find most alluring—specifically, those unprotected by repellents that drive them away.

What the researchers now  found was that the chemicals were not able to activate the mosquito wasabi receptor as effectively when temperatures exceeded the heat activation threshold.

Typical insect repellents create a chemical barrier that discourages proximity and prevents mosquitoes from reaching their target. Yet because their receptors are desensitized in warmer temperatures, natural substances like citronellal and catnip oil, known for their repellent properties, would be less effective. Products with those ingredients may be less effective if you're using them at temperatures that are considered extreme heat events, say the researchers.

Yeaeun Park et al, Heat activation desensitizes Aedes aegypti transient receptor potential ankyrin 1 (AaTRPA1) to chemical agonists that repel mosquitoes, Pesticide Biochemistry and Physiology (2025). DOI: 10.1016/j.pestbp.2025.106326

Comment by Dr. Krishna Kumari Challa on March 13, 2025 at 8:50am

Food insecurity raises risk of heart disease over time: A 20 year study

Struggling to afford food today could mean heart problems tomorrow. Young adults experiencing food insecurity have a 41% greater risk of developing heart disease in midlife, even after accounting for demographic and socioeconomic factors, according to a new  Medicine study.

Food insecurity means struggling to get enough nutritious food to stay healthy.

That makes it a clear target for prevention—if we address food insecurity early, we may be able to reduce the burden of heart disease later."

The study was published in JAMA Cardiology.

Among the 3,616 study participants, those experiencing food insecurity were 41% more likely to develop cardiovascular disease than their food-secure counterparts. Over the study period, 11% of food-insecure individuals developed heart disease, compared to 6% of those with adequate food access.

By following people over two decades, researchers were able to show that food insecurity, on its own, significantly increases the risk of developing cardiovascular disease. 

 Food Insecurity and Incident Cardiovascular Disease Among Black and White US Individuals, 2000-2020, JAMA Cardiology (2025). DOI: 10.1001/jamacardio.2025.0109

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