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Comment by Dr. Krishna Kumari Challa on Saturday

Origins of the 'Ostrich Effect': Researchers pinpoint the age we start avoiding information—even when it's helpful

In a world of information overload, it can feel soothing to stick your head in the sand.

According to psychologists, avoiding information when it's uncomfortable is a common adult behavior, often referred to as the "Ostrich Effect."

But how do we become an ostrich? Children are notorious for seeking out information, often in the form of endless questions. So when do we sprout feathers and decide that, actually, the number of calories in a slice of cake is none of our business?

This behavioral origin point was exactly what researchers wanted to pin down.

In a study published in Psychological Science, a research team discovered that as children aged, the tendency to avoid information grew stronger.

Though 5- and 6-year-olds still actively sought information, 7- to 10-year-olds were much more likely to strategically avoid learning something if it elicited a negative emotion.

Why is it that children are these super curious people, but then we somehow end up as these information avoiders as adults?

In their initial experiment, the researchers looked at five reasons why we might willfully choose to remain ignorant:
To avoid negative emotions like anxiety or disappointment
To avoid negative information about our own likability or competence
To avoid challenges to our beliefs
To protect our preferences
To act in our own self-interest (perhaps while trying to appear not self-interested)
Part 1

Comment by Dr. Krishna Kumari Challa on Saturday

Million-year-old skull could change human evolution timeline

A digital reconstruction of a million-year-old skull suggests humans may have diverged from our ancient ancestors 400,000 years earlier than thought and in Asia not Africa, a study said this week.

The findings are based on a reconstruction of a crushed skull discovered in China in 1990, and have the potential to resolve the longstanding "Muddle in the Middle" of human evolution, researchers said.

But experts not involved in the work cautioned that the findings were likely to be disputed, and pointed to ongoing uncertainties in the timeline of human evolution.

The skull, labeled Yunxian 2, was previously thought to belong to a human forerunner called Homo erectus.

But modern reconstruction technologies revealed features closer to species previously thought to have existed only later in human evolution, including the recently discovered Homo longi and our own Homo sapiens.

It suggests that by one million years ago, our ancestors had already split into distinct groups, pointing to a much earlier and more complex human evolutionary split than previously thought.

If the findings are correct, it suggests there could have been much earlier members of other early hominins, including Neanderthals and Homo sapiens, the study says.

It also "muddies the waters" on longstanding assumptions that early humans dispersed from Africa.

There's a big change potentially happening here, where east Asia is now playing a very key role in hominin evolution.

The research, published in the journal Science, used advanced CT scanning, structure light imaging and virtual reconstruction techniques to model a complete Yunxian 2.

The scientists relied in part on another similar skull to shape their model, and then compared it to over 100 other specimens.

The resulting model "shows a distinctive combination of traits," the study said, some of them similar to Homo erectus, including a projecting lower face.

But other aspects, including its apparently larger brain capacity, are closer to Homo longi and Homo sapiens, the researchers said.

"Yunxian 2 may help us resolve what's been called the 'Muddle in the Middle,' the confusing array of human fossils from between 1 million and 300,000 years ago.

The findings are only the latest in a string of recent research that has complicated what we thought we know about our origins.

Xiaobo Feng et al, The phylogenetic position of the Yunxian cranium elucidates the origin of Homo longiand the Denisovans, Science (2025). DOI: 10.1126/science.ado9202

Comment by Dr. Krishna Kumari Challa on September 26, 2025 at 9:10am

Mucus contains molecules that block Salmonella infection, study reveals

Mucus is more than just a sticky substance: It contains a wealth of powerful molecules called mucins that help to tame microbes and prevent infection. In a new study,  researchers have identified mucins that defend against Salmonella and other bacteria that cause diarrhea.

The researchers now hope to mimic this defense system to create synthetic mucins that could help prevent or treat illness in soldiers or other people at risk of exposure to Salmonella. It could also help prevent "traveler's diarrhea," a gastrointestinal infection caused by consuming contaminated food or water.

Mucins are bottlebrush-shaped polymers made of complex sugar molecules known as glycans, which are tethered to a peptide backbone. In this study, the researchers discovered that a mucin called MUC2 turns off genes that Salmonella uses to enter and infect host cells.

Mucus lines much of the body, providing a physical barrier to infection, but that's not all it does.

Researchers identified mucins that can help to disarm Vibrio cholerae, as well as Pseudomonas aeruginosa, which can infect the lungs and other organs, and the yeast Candida albicans.

The researchers found in the new study that when they exposed Salmonella to a mucin called MUC2, which is found in the intestines, the bacteria stopped producing the proteins encoded by SPI-1, and they were no longer able to infect cells.

Further studies revealed that MUC2 achieves this by turning off a regulatory bacterial protein known as HilD. When this protein is blocked by mucins, it can no longer activate the T3SS genes.

Using computational simulations, the researchers showed that certain monosaccharides found in glycans, including GlcNAc and GalNAc, can attach to a specific binding site of the HilD protein. However, their studies showed that these monosaccharides can't turn off HilD on their own—the shutoff only occurs when the glycans are tethered to the peptide backbone of the mucin.

The researchers also discovered that a similar mucin called MUC5AC, which is found in the stomach, can block HilD. And, both MUC2 and MUC5AC can turn off virulence genes in other foodborne pathogens that also use HilD as a gene regulator.

The researchers now plan to explore ways to use synthetic versions of these mucins to help boost the body's natural defenses and protect the GI tract from Salmonella and other infections.

Kelsey M. Wheeler et al, Mucus-derived glycans are inhibitory signals for Salmonella Typhimurium SPI-1-mediated invasion, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.116304

Comment by Dr. Krishna Kumari Challa on September 26, 2025 at 9:03am

Squirrels bite when they feel threatened, cornered, or are aggressively seeking food. They can also bite inadvertently by mistaking a finger for a treat or startling when a hand is presented to them. While usually a defensive action or a form of play, squirrels lack the bite inhibition of domesticated animals, and their bites, though not typically malicious, can be deep and pose a risk of infection. 

Reasons for biting:

Self-defense: Like any wild animal, squirrels will bite to protect themselves if they feel endangered.
Aggression for food: Squirrels may become aggressive if they are accustomed to being fed by humans and approach to get a meal, according to Critter Control.
Accidental bites: Squirrels don't have the same depth perception as humans and can mistakenly bite a finger when trying to take a treat.
Nesting: A mother squirrel in a nesting area, such as an attic, may bite if she feels cornered or threatened.
Play behaviour: Squirrels also "play bite" to practice skills they will use as adults, similar to how siblings interact.
Risks of a squirrel bite:
Infection: Because squirrels are wild rodents, a bite can lead to an infection.
Diseases: Though rabies is rare in squirrels, they can carry other diseases, such as the plague, which is transmitted by fleas.
What to do if a squirrel bites:
Wash the wound: Immediately wash the wound thoroughly with soap and water to reduce the risk of infection.
Seek medical attention: Consult a healthcare professional to determine if a tetanus shot is needed and to monitor for any signs of infection.

Comment by Dr. Krishna Kumari Challa on September 26, 2025 at 8:59am

Trees are dying at an alarming rate

The rise in tree mortality is troubling for local forest ecosystems. As a global phenomenon, however, it has a significant social impact that remains poorly understood.

We don't currently know whether climate change will lead to the death of 10% or 50% of all trees worldwide.

An international group of more than 100 forest researchers are reviewing almost 500,000 forest monitoring studies from 89 countries and five continents. The researchers found that the main cause of tree mortality is anthropogenic (human-induced) climate change and its consequences: heat, dry air and soil, forest fires, storms, and increased insect damage and plant diseases.  

In the article published in New Phytologist, the researchers aimed to identify methods, requirements and data gaps in monitoring tree mortality trends. 

Towards a global understanding of tree mortality, New Phytologist (2025). DOI: 10.1111/nph.20407

Comment by Dr. Krishna Kumari Challa on September 26, 2025 at 8:50am

Camouflage or caution? How anti-predator strategies have evolved

Predators and the environment determine why some animals use camouflage to avoid being eaten, while others use bright colors to warn them off, new research reveals. Published recently  in the journal Science, the findings help explain the evolution and global distribution of the most common color strategies used by insects to avoid predators.

The global study took place across six continents and involved over 50 scientific collaborators.

Using the same experiment, researchers deployed more than 15,000 artificial prey with three different colors to investigate which strategy works best to deter predators: a classic warning pattern of orange and black, a dull brown that blends in, and an unusual bright blue and black.

The researchers found the answer to why some animals use camouflage over warning colors to deter predators turned out to be more complex than expected.

The findings showed there is no single best color strategy to deter predators, but that context is critical. The different characteristics of the predator and prey communities, as well as habitat in that part of the globe, heavily decide which strategy performs better in each place. This makes sense when we see animals employing so many varying camouflage and warning color strategies as defense systems all over the world.

Predators had the biggest influence on which color strategy was most successful for prey, the study revealed.

In environments where predators are competing intensely for food, they are more likely to risk attacking prey that might be dangerous or distasteful. Hence, the researchers saw that camouflage worked best in areas with lots of predation.

Whereas, in places where cryptic prey (insects who use camouflage) are abundant, hiding becomes less effective, as predators are better at looking for those types of animals.

The findings help scientists understand why some species, such as the cryptic bogong moth or the brightly colored harlequin bug, have evolved their strategies against predators.

 Iliana Medina et al, Global selection on insect antipredator coloration, Science (2025). DOI: 10.1126/science.adr7368. www.science.org/doi/10.1126/science.adr7368

Comment by Dr. Krishna Kumari Challa on September 26, 2025 at 8:40am

Scientists discover that cell nucleus is actually less dense than surrounding cytoplasm

Just as life pulsates in big vibrant cities, it also prospers in crowded environments inside cells. The interior of cells is densely packed with biomolecules like proteins and nucleic acids. How is all this material distributed within a cell and what regulates its distribution?

In a study published in Nature Communications, researchers measure subcellular densities across a wide range of organisms. Their aim is to better understand biomolecular processes ranging from yeast cells  to human cells.

Conventional scientific textbooks describe the cell nucleus as a compartment packed with an impressive amount of DNA wrapped around histone proteins.

Now, an international team of researchers has discovered that—contrary to expectations—the nucleus is less dense than the surrounding cytoplasm.

Despite their rich biomolecular composition, nuclei contain less dry mass than the same volume of the surrounding cytoplasm.

How can density be measured in microscopic objects such as individual cell compartments? Scientists use light for this purpose. Not only does light allow cells to be examined, it also enables them to be manipulated. Light can exert forces, enabling laser beams to "pull" on cells and measure their mechanical properties using an "optical stretcher."

The researchers developed an optical setup which allowed them to obtain three-dimensional density distributions inside cells at high resolution by combining optical diffraction tomography and confocal fluorescence microscopy.

While NC density ratios are maintained from yeast to human cells, we do start seeing deviations in disease. During stressed cellular states such as aging, the so-called senescence, cell nuclei become denser than the cytoplasm. Thus, the study points to the fundamental importance of density as a variable that determines healthy cellular processes, the researchers note in their paper.

 Abin Biswas et al, Conserved nucleocytoplasmic density homeostasis drives cellular organization across eukaryotes, Nature Communications (2025). DOI: 10.1038/s41467-025-62605-0

Comment by Dr. Krishna Kumari Challa on September 25, 2025 at 1:30pm

Lab-grown kidneys yield urine
Researchers have created the most sophisticated kidney organoid to date, offering a real shot at growing transplantable kidneys from stem cells. These mini kidneys were capable of making urine when transplanted into mice. “You wouldn’t mistake it for a real kidney,” says experimental anatomist Jamie Davies. “But it is trying to do the right things.” Plumbing — encouraging the organoid to develop blood vessels and the duct that carries urine to the bladder — is the major hold-up. The researchers estimate a transplantable kidney will be ready for animal testing in less than five years.

https://www.sciencedirect.com/science/article/abs/pii/S193459092500...

https://www.science.org/content/article/scientists-make-most-authen...

Comment by Dr. Krishna Kumari Challa on September 25, 2025 at 12:27pm

A new look at how the brain works reveals that wiring isn't everything

How a brain's anatomical structure relates to its function is one of the most important questions in neuroscience. It explores how physical components, such as neurons and their connections, give rise to complex behaviors and thoughts. A recent study of the brain of the tiny worm C. elegans provides a surprising answer: Structure alone doesn't explain how the brain works.

C. elegans is often used in neuroscience research because, unlike the incredibly complex human brain, which has billions of connections, the worm has a very simple nervous system with only 302 neurons. A complete, detailed map of every single one of its connections, or brain wiring diagram (connectome), was mapped several years ago, making it ideal for study.

In this research, scientists compared the worm's physical wiring in the brain to its signaling network, how the signals travel from one neuron to another. First, they used an electron microscope to get a detailed map of the physical connections between its nerve cells. Then, they activated individual neurons with light to create a signaling network and used a technique called calcium imaging to observe which other neurons responded to this stimulation.

Finally, they used computer programs to compare the physical wiring map and the signal flow map, identifying any differences and areas of overlap.

The team discovered that the brain's functional organization differs from its anatomical structure. An analogy is that the brain's structure is like a city map showing every street. However, the function is more akin to traffic flow, with jams, detours and shortcuts that are not visible on the map. In other words, brain activity does not always follow the predictable pathways of its physical wiring.

Sophie Dvali et al, Diverging Network Architecture of the C. elegans Connectome and Signaling Network, PRX Life (2025). DOI: 10.1103/6wgv-b9m6

Comment by Dr. Krishna Kumari Challa on September 25, 2025 at 12:02pm

AI-generated voices now indistinguishable from real human voices

Many people still think of AI-generated speech as sounding "fake" or unconvincing and easily told apart from human voices. But new research shows that AI voice technology has now reached a stage where it can create "voice clones" or deepfakes which sound just as realistic as human recordings.

The study compared real human voices with two different types of synthetic voices, generated using state-of-the-art AI voice synthesis tools. Some were "cloned" from voice recordings of real humans, intended to mimic them, and others were generated from a large voice model and did not have a specific human counterpart.

Participants were asked to evaluate which voices sounded most realistic, and which sounded most dominant or trustworthy. Researchers also looked at whether AI-generated voices had become "hyperreal," given that some studies have shown that AI-generated images of faces are now judged to be human more often than images of real human faces.

While the study did not find a "hyperrealism effect" from the AI voices, it did find that voice clones can sound as real as human voices, making it difficult for listeners to distinguish between them. Both types of AI-generated voices were evaluated as more dominant than human voices, and some were also perceived as more trustworthy.

Voice clones sound realistic but not (yet) hyperrealistic, PLOS One (2025). DOI: 10.1371/journal.pone/0332692

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