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Comment by Dr. Krishna Kumari Challa 28 minutes ago

Why plastic lingers: Water chemistry slows nature's cleanup

Scientists have long known that sunlight helps break down plastic. So, why do plastic products linger for decades and even centuries in rivers, lakes, and oceans—even when bathed in direct sunlight? Researchers have uncovered an unexpected answer. The surprising culprit is the water itself.
Natural water chemistry, particularly the presence of salts and organic matter, significantly slows the photodegradation of polystyrene plastics by competing for sunlight and suppressing reactive processes. As a result, plastics degrade much faster in purified water than in freshwater or seawater, limiting microbial breakdown and contributing to their persistence in natural environments.
In a new study designed to mimic real environmental conditions, researchers found that the chemical makeup of natural waters—especially combinations of salt and organic matter—significantly delays the breakdown of polystyrene, a common plastic used in packaging and food containers.

Because sunlight cannot effectively initiate the degradation process, microbes cannot finish the job. That means nature's cleanup process slows down, allowing plastics to accumulate and persist in waterways around the world.

The findings show that solving plastic pollution isn't only about the material itself but also about the environment it enters. These insights could be used to design new types of plastic that degrade even in salty, complex environments or that don't rely on sunlight to jump-start the breakdown process.

Polystyrene photooxidation in natural waters as a precursor to microbial degradation, npj Materials Degradation (2026). DOI: 10.1038/s41529-026-00788-7

Comment by Dr. Krishna Kumari Challa 38 minutes ago

The Milky Way was rewired by a cataclysmic collision billions of years ago. Now it is on course for another
The Milky Way underwent a major collision with a dwarf galaxy 8–11 billion years ago, fundamentally altering its structure, stellar populations, and dark matter halo. Evidence of this event persists in the form of stars with distinct orbits and chemical signatures. Currently, the Milky Way is being gravitationally disturbed by the Large Magellanic Cloud, setting the stage for another significant galactic interaction.

original article.

Comment by Dr. Krishna Kumari Challa 40 minutes ago

Galaxy-killing wind discovered in the early universe
Observations of the early universe reveal that intense star formation and galaxy collisions can drive powerful winds that expel star-forming gas from galaxies, rapidly quenching their growth. The galaxy CRISTAL-02 exhibits such a wind, ejecting material at twice the rate of star formation, potentially leading to its death within 50 million years. This mechanism may explain the unexpectedly high number of massive, dead galaxies observed in the early universe.

Rebecca L Davies et al, Multiphase images of a powerful supernova-driven wind in the early Universe, Monthly Notices of the Royal Astronomical Society (2026). DOI: 10.1093/mnras/stag874

Comment by Dr. Krishna Kumari Challa 2 hours ago

People have an inherent preference for counter-clockwise motion, study reveals

Researchers in Spain and Japan tested a broad range of pedestrians in varying group sizes to see whether there were any patterns in their turning behaviours, and what factors influenced them, if any. It turns out that the vast majority of people prefer counter-clockwise turning. Most factors, such as culture or gender, made little difference. Only age showed a noticeable but small change, in that younger people followed this pattern more strongly.
When analyzing the experiments, researchers realized by chance that in 32 out of 33 experimental trials, as people moved and turned, they noticeably preferred to turn counterclockwise.
This was completely unexpected as, at least instinctively, when people walk around randomly, you imagine people turn as their needs suit them, with little sign of an overall preference. But there was a definite, measurable tendency for people to turn counterclockwise over clockwise, all things being equal.
The team had to understand the reason for this, and all good research practice dictates that you test observations against multiple possible causes to narrow down what's really going on.
Feliciani and his team set up experiments to observe pedestrian test subjects in different open and constrained environments. Not only did they test cultural background by having parallel tests in Spain and Japan, they also investigated group size, gender, handedness and age.

Of all these things, the only thing that stood out was that kids tend to have a stronger bias for the counterclockwise direction, so probably age plays a role in making the effect weaker or stronger.
These results may appear to be a minor, insignificant discovery, but in nature, most phenomena related to locomotion show that animals mostly walk without directional preference. The strong bias found in people hints at some asymmetry at the biomechanical level.
There are some interesting parallels to certain sports. Some running and driving competitions are always, but inexplicably, held on courses that run counterclockwise.

Individual locomotor bias drives counterclockwise motion in pedestrian crowds, Nature Communications (2026). DOI: 10.1038/s41467-026-73713-w

Comment by Dr. Krishna Kumari Challa yesterday

Celiac risk may begin with weaker helper T cells, not just overactive immunity

New research is challenging long-held assumptions about autoimmune disease, revealing that celiac disease may be driven not just by an overactive immune system, but by subtle defects in how immune cells function.
Published in Immunology & Cell Biology, the study found consistent shifts in immune cell behavior in people with celiac disease—differences that may appear long before symptoms develop.

Researchers identified distinct patterns in early immune responses that could help predict autoimmune risk and support more personalized monitoring and care in future.
The research examined a type of immune cell known as CD4 helper T cells, which coordinate immune responses, fight infection and support antibody production.
Contrary to expectations, immune cells from people with celiac disease were not simply overactive. Instead, they showed weaker responses.

The study found CD4 helper T cells from people with celiac disease:

produced less interleukin-2, a key immune signalling molecule
entered cell division more slowly
were less likely to survive

These differences were subtle but remarkably consistent.
Notably, the same pattern appeared regardless of sex or whether individuals were newly diagnosed or managing the condition with a gluten-free diet.

This tells us the effect isn't simply driven by inflammation or diet. It suggests an underlying difference that may be linked to genetic risk.
Although the study focused on celiac disease, the findings may have broader relevance.

Autoimmune diseases affect around 5% of the population, and many share overlapping genetic risk factors.

If autoimmune risk is partly built into how immune cells behave from the start, this could change how we think about early detection.

Anthony J Farchione et al, Functional immune profiling reveals CD4⁺ T cell dysregulation in coeliac disease, Immunology & Cell Biology (2026). DOI: 10.1111/imcb.70132

Comment by Dr. Krishna Kumari Challa yesterday

Eating in the middle of the night can cause gastrointestinal issues

Eating during the body's usual sleep period disrupts synchronization among intestinal cell circadian clocks, with interstitial cells of Cajal (ICCs) showing resistance to phase shifts. This desynchronization may impair intestinal motility and contribute to gastrointestinal disorders linked to circadian rhythm disturbances, such as those experienced by shift workers or during jet lag.

Eating when the body is normally asleep appears to desynchronize the circadian clocks of different cell types in the intestines, a new study suggests. The findings, published in PNAS, could help explain why shift work, jet lag and other environmental stressors that affect circadian rhythms are associated with irritable bowel syndrome, inflammatory bowel disease, constipation and other gastrointestinal disorders.
Research in the 1990s and 2000s showed that a region of the brain known as the suprachiasmatic nucleus (SCN) acts as a master timekeeper for the body, setting various cellular processes to occur rhythmically over a 24-hour period based on cycles of light and darkness.

However, in 2000, Yamazaki and his colleagues showed that cells throughout the body have their own autonomous circadian clocks that are influenced both by signals from the SCN and environmental cues.

In line with this idea, research has shown that the intestines have their own rhythms that can be influenced by a variety of factors, such as the timing of meals.

These findings were made using whole intestinal tissue but the intestines contain a variety of cell types, including muscle, nerve and immune cells. It has been unclear whether each of these populations has its own circadian clock and whether they run on the same schedule.
To find out, researchers monitored novel mice on set 12-hour cycles of light and dark.
Five intestinal cell types—enteric neurons, enteric glial cells, interstitial cells of Cajal (ICCs), smooth muscle cells and muscularis macrophages—glowed green when a key circadian clock gene called Per2 was active. Although food was available at all times, the mice ate about 80% of their meals at night because of their nocturnal nature.

After about a week in this environment, the researchers observed intestinal cells glowing green at approximately the same times, suggesting the different cell populations had their own autonomous circadian clocks that cycled in sync.

However, when the researchers made food available only for four hours during the daytime—forcing the mice to eat at abnormal times—Per2 activity shifted to match this new rhythm in every cell population except for the ICCs. These cells resisted changes to their circadian clock, staying out of sync with the other cell types for weeks.
Such asynchrony may also occur in people who eat outside the body's usual circadian rhythms, such as night shift workers or those who fly to different time zones. Because ICCs play a key role in intestinal motility, their resistance to adapting to a changed circadian clock could affect digestive and metabolic function.

Finding a way to synchronize the different intestinal cell populations through diet, probiotics or drugs could eventually help ease the gastrointestinal problems associated with altered circadian timing, the researchers say.

Isabel Magaña et al, Not all gut cellular circadian oscillators are food entrainable, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2601012123

Comment by Dr. Krishna Kumari Challa yesterday

Fathers may influence their children's health before they're even conceived
Paternal metabolic information influencing offspring health is established during sperm development in the testis, not acquired later during sperm maturation in the epididymis. Mature sperm lack mitochondrial DNA-driven transcription, indicating that preconception paternal health can shape offspring metabolic traits via mechanisms set during spermatogenesis.

Testicular origin of epigenetic inheritance independent of sperm mitochondrial DNA and epididymal exposure, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2611096123. doi.org/10.1073/pnas.2611096123

Comment by Dr. Krishna Kumari Challa yesterday

The birds got scared of the genet in cooler temperatures—they'd call out, scan their surroundings, or simply flee. But once it got hot, they behaved similarly whether they were facing the carnivore or the box. Ridley suggests that this could translate into higher chances of fatal predator attacks as heat rises, which could harm populations of babblers and other prey species.

These studies are not just abstractions. In the Kalahari, where southern pied babblers use their wits to search for worms, temperatures are rising twice as fast as the global average. In tropical rivers, where male guppies seek mates, heat waves are growing longer and more intense. It's the same story across much of the planet—temperatures climb, and animal thinking becomes strained, potentially putting species at risk. The effects may be magnified in certain areas such as cities, which often exhibit even warmer temperatures than nonurban areas.

If anything, Ridley says, "We are probably underestimating the impacts of increased heat on animal minds."

Heat hampers brain cells
In addition to highlighting behavioral changes, animal studies can also offer insight into how heat meddles with brain cells. Experiments with mice, for example, show that poor performance in hot mazes is linked to inflammation in the hippocampus, the brain's memory center, and can lead to the death of neurons there. If fruit flies are exposed to heat in early life, their adult brains have fewer mushroom bodies—structures that are important for insect learning. And a 2025 study on cleaner wrasses, a fish species that cleans parasites off other fish, showed that after a heat wave, a key part of the fish brain that controls cognitive functions such as memory shrank considerably.
Part 3

Comment by Dr. Krishna Kumari Challa yesterday

Cognitive problems
Heat waves can also hamper the ability of animals to learn, as Ridley and her colleagues observed with the southern pied babblers. In one of their experiments, the birds were presented with a simple wooden block with two holes drilled in it, each covered with a lid. If the bird pecked at the lid, it would rotate, revealing either an empty hole or a tasty mealworm. The babblers, Ridley says, "are highly motivated by mealworms."

One lid was dark, and the other a lighter shade of the same color. During heat waves, the birds needed twice as many trials to learn that the mealworm was always hidden under the lid of the same shade.

Another group of scientists tested zebra finches, pretty Australian songbirds, and discovered that if temperatures are high, they too have cognitive problems. When figuring out how to get a mealworm out of a see-through tube with an opening at one end, they would just keep pecking on the tube, says study co-author Elizabeth Derryberry, an evolutionary biologist at the University of Tennessee, Knoxville.

It's the bird equivalent of "banging your head against a brick wall.
Adding to the tally, several years ago researchers showed that when the heat is on, mice have trouble finding their way around a maze and forget objects they've seen the day before. More recently, researchers found that male guppies, popular aquarium fish, also have trouble getting through a maze after spending several days in heat-wave-like 90-degree water, even if the prize for getting it right is a virgin female—which they tend to find particularly attractive.

For animals such as fish and insects that can't control their body temperature, heat waves could be particularly detrimental. "Changes in air temperature will affect brain temperature," says Baird. A hotter brain could hinder the functioning of nerves, and that, she says, "might affect sensing, memory and learning."

When Baird and colleagues tried to teach bumblebees to associate sweet sucrose with the color blue and bitter quinine with yellow, most of the bumblebees learned the trick at 77 degrees, but fewer than half managed to do so at 90 degrees. Such impaired cognition could spell trouble in the field. If the insects forget which flowers they should pollinate—in the case of bumblebees, these include tomatoes and blueberries—or how to get back home with nectar, not only will the pollinators suffer, but human agriculture too, Baird says.

Heat appears to dangerously diminish animal vigilance as well. In Ridley's recent experiments, once the mercury in the Kalahari Desert reached 96 degrees Fahrenheit, pied babblers lost their ability to properly respond to predators. In their studies, researchers lured birds toward a mystery shape covered in a sandy-colored blanket, using worms as bait. Once a babbler approached, the scientists would reveal what was hidden underneath: either a taxidermied catlike carnivore called a genet, or a similarly sized and colored wooden box.
Part 2

Comment by Dr. Krishna Kumari Challa yesterday

They call it 'stupid hot' for a reason: Heat muddles animal brains

There is plenty of evidence that animals are affected by heat. Birds, for example, spend less time looking for food and feeding their young; they even sing less. Instead, they'll sit around for hours with wings spread to dissipate the heat, and pant with their beaks wide open. Some animals retreat to shade or hide in cool burrows—again, skipping meals. Bees, meanwhile, splash their faces with droplets of water midflight when the weather is sizzling. This way, "they get convective cooling for their brain.

Some of the first hints that hot temperatures can mess up minds, however, came from studies on humans. Back in the 1800s, Belgian astronomer Adolphe Quetelet noticed that violent crime in France peaked in the summer. Later studies linked high temperatures with gun violence, mental health-related hospital admissions, suicide and gambling. When it's hot, people have trouble making decisions, and their memory suffers. For students at schools without air conditioning, a school year just 1 degree Fahrenheit hotter reduces test scores by 1%, a study found.

Increasingly, there's evidence that other species may also be more aggressive when the mercury shoots up. A 2023 study that combed through nearly 70,000 reports of dogs biting people across eight U.S. cities, from Chicago to Baltimore, found that such incidents were more likely to happen on hot, sunny and smoggy days. The risk was 10% higher on a 90-degree day than on a 60-degree day—and not only because people are more apt to venture out for walks when the sun is shining. The researchers controlled for seasonal effects in their data.
It's likely that both humans and dogs get stressed and more irate at higher temperatures.

Elevated temperatures impair cognitive function and increase aggression in various animal species, affecting learning, memory, decision-making, and social interactions. Heat waves reduce animals' ability to find food, avoid predators, and perform essential behaviours, potentially threatening survival and ecosystem stability. Neurological effects include inflammation, neuron loss, and structural brain changes.

And it's not only dogs: A 2025 study out of China showed that many animals, including snakes and cats, are more inclined to bite people when it gets hot.

Animals also seem to lose their cool with each other, especially if food is involved. Scientists used binoculars and spotting scopes to spy on wild goat-like chamois that feed on protein-rich plants on the slopes of the Italian Apennine Mountains. More than 1,600 hours of observations over two summers revealed that when temperatures rose from 54 degrees Fahrenheit to 64 degrees Fahrenheit, vegetation grew scarcer, and chamois aggression in turn shot up.

The animals became territorial over patches of food. They assumed threatening postures and chased each other—attacks that, at times, escalated. The study authors predict that chamois aggression will go up 50% by 2080 because of climate change.

The small tropical fish called a golden julie also gets confrontational in the heat. Ordinarily, when a golden julie is placed in front of a mirror, it sees its reflected image as a stranger and shows some hostility, raising its fin, for example. But if the normally 78-degree water is raised to a hot 84 degrees, the fish is more likely to get aggressive, and may bite and slap its tail against the mirror as it tries to scare or attack the reflected image.
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