Comment

Comment by Dr. Krishna Kumari Challa 12 hours ago

The results are consistent with recent archaeological discoveries and align with a body of evidence that suggests the decline of Neanderthals in Europe was gradual rather than sudden.

Homo sapiens seem to have started migrating out of Africa much earlier than scientists previously thought, and they arrived in Europe in several influxes, possibly starting more than 200,000 years ago.
As each wave of migration came crashing into the region, it engulfed local Neanderthal communities, diluting their genes, like sand pulled into the sea.
Today, some scientists argue that there is more to unite Homo sapiens and Neanderthals than there is to differentiate us. Our lineages, they say, should not be regarded as two separate species, but rather as distinct populations belonging to a "common human species.".

Neanderthals were surprisingly adaptable and intelligent. They made intricate tools, created cave art, and used fire – and when it came to communication, they were probably capable of far more than simple grunting.
Neanderthal populations and cultures may no longer exist, but their genetic legacy lives on inside of us.
These are not just our cousins; they are also our ancestors.

https://www.nature.com/articles/s41598-025-22376-6

Part 2

**

Comment by Dr. Krishna Kumari Challa 12 hours ago

Neanderthals May Never Have Truly Gone Extinct

Neanderthals may have never truly gone extinct, according to new research – at least not in the genetic sense.

A new mathematical model has explored a fascinating scenario in which Neanderthals gradually disappeared not through "true extinction" but through genetic absorption into a more prolific species: Us.
According to the analysis, the long and drawn-out 'love affair' between Homo sapiens and Neanderthals could have led to almost complete genetic absorption within 10,000–30,000 years.
The model is simple and not regional, but it provides a "robust explanation for the observed Neanderthal demise, say researchers.
Once, the idea that Neanderthals and Homo sapiens interbred was a radical notion, and yet now, modern genome studies and archaeological evidence have provided strong evidence that our two lineages were hooking up and reproducing right across Eurasia for tens of thousands of years.

Today, people of non-African ancestry have inherited about 1 to 4 percent of their DNA from Neanderthals.
No one knows why Neanderthals disappeared from the face of our planet roughly 40,000 years ago, but experts tend to agree that there are probably numerous factors that played a role, like environmental changes, loss of genetic diversity, or competition with Homo sapiens.
Now researchers present a model that does not rule out these other explanations.
It does suggest that genetic drift played a strong role – even with the researchers assuming the Neanderthal genes our species 'absorbed' had no survival benefit.

If the model were to include the potential advantages of some Neanderthal genes to the larger Homo sapiens population, then mathematical support for genetic dilution may become even stronger.

Like all models, this new one is based on imperfect assumptions. It uses the birth rates of modern hunter-gatherer tribes to predict how quickly small Neanderthal tribes would be engulfed by a much larger human population, given how frequently it seems we were interbreeding.
Part 1

Comment by Dr. Krishna Kumari Challa 13 hours ago

Direct link between peak air pollution and cardiac risk revealed

The risk of suffering cardiac arrest may increase on days recording high levels of air pollution in some parts of the world. This emerges from a study conducted by researchers and published in the journal Global Challenges.

Researchers analyzed 37,613 cases of out-of-hospital cardiac arrest in Lombardy between 2016 and 2019 by assessing, for each episode, the daily concentrations of various pollutants (PM₂.₅, PM₁₀, NO₂, O₃ and CO) obtained from satellite data of the European Copernicus program (ESA). The study used advanced spatio-temporal statistical models to identify the relationship between pollution peaks and increased risk of cardiac events.

They observed a strong association with nitrogen dioxide (NO₂). Indeed, for every 10 micrograms per cubic meter increase, the risk of cardiac arrest rises by 7% over the next 96 hours.

Even particulate matter PM₂.₅ and PM₁₀ present a 3% and 2.5% increase in the risk rate, respectively, on the same day of exposure.

The effect is more pronounced in urban areas but significant associations are also observed in rural towns. The risk particularly marks an upswing in the warm months, suggesting a possible interaction between heat and pollutants. The association was also observed at levels below legal limits, suggesting that there is no safe exposure threshold.

The link between air quality and out-of-hospital cardiac arrest is a wake-up call for local health systems.

 Amruta Umakant Mahakalkar et al, Short‐Term Effect of Air Pollution on Out of Hospital Cardiac Arrest (OHCA) in Lombardy—A Case‐Crossover Spatiotemporal Study, Global Challenges (2025). DOI: 10.1002/gch2.202500241

Comment by Dr. Krishna Kumari Challa 13 hours ago

AI at the speed of light just became a possibility

Researchers have demonstrated single-shot tensor computing at the speed of light, a remarkable step towards next-generation artificial general intelligence hardware powered by optical computation rather than electronics.

Tensor operations are the kind of arithmetic that form the backbone of nearly all modern technologies, especially artificial intelligence, yet they extend beyond the simple math we're familiar with. Imagine the mathematics behind rotating, slicing, or rearranging a Rubik's cube along multiple dimensions. While humans and classical computers must perform these operations step by step, light can do them all at once.

Today, every task in AI, from image recognition to natural language processing, relies on tensor operations. However, the explosion of data has pushed conventional digital computing platforms, such as GPUs, to their limits in terms of speed, scalability and energy consumption.

Motivated by this pressing problem, an international research collaboration has unlocked a new approach that performs complex tensor computations using a single propagation of light. The result is single-shot tensor computing, achieved at the speed of light itself.

The new method performs the same kinds of operations that today's GPUs handle, like convolutions and attention layers, but does them all at the speed of light.

To achieve this, the researchers encoded digital data into the amplitude and phase of light waves, effectively turning numbers into physical properties of the optical field. When these light fields interact and combine, they naturally carry out mathematical operations such as matrix and tensor multiplications, which form the core of deep learning algorithms.

By introducing multiple wavelengths of light, the team extended this approach to handle even higher-order tensor operations.

Another key advantage of this method is its simplicity. The optical operations occur passively as the light propagates, so no active control or electronic switching is needed during computation.

Direct tensor processing with coherent light, Nature Photonics (2025). DOI: 10.1038/s41566-025-01799-7.

Comment by Dr. Krishna Kumari Challa on Friday

What puts the ‘cable’ in cable bacteria
The ‘wires’ that cable bacteria use to conduct electricity seem to be made of repeating units of a compound that contains nickel and sulfur. Researchers found that these units make up ‘nanoribbons’, which are woven together like a plait to form the larger wires. The work has yet to be peer reviewed, but if confirmed, the finding could be the first known example of a biologically produced metal–organic framework. “If it holds true, this is a major step in our understanding of what cable bacteria can accomplish,” says electromicrobiologist Lars Peter Nielsen, who co-discovered the microorganisms in 2009.

https://www.biorxiv.org/content/10.1101/2025.10.10.681601v1

https://www.science.org/content/article/metal-scaffolds-turn-bacter...

Comment by Dr. Krishna Kumari Challa on Friday

The new review is based on 13 randomized trials presented in 26 articles containing more than 1,400 separate statistical analyses. Only one of the 13 randomized trials demonstrated the effect it was designed to detect—and that trial was stopped early and was considered unsuccessful by the researchers themselves.

The review showed that only about 7% of the many hypotheses tested by the researchers could be expected to be correct. Notably, this did not apply to the researchers' own primary hypotheses—these were not supported by the corrected results.

In 23 out of 25 articles, the researchers highlighted secondary findings as support for their theories, but in 22 of these cases the evidence disappeared after proper statistical handling. Overall, the researchers' interpretation did not take into account how many analyses they had conducted, and they did not focus on the main outcomes of the trials.
The researchers stress that the purpose was not to determine whether non-specific vaccine effects exist, but to examine Benn and Aaby's research practices.

"We hope that others in the field will now re-evaluate the evidence—what do we actually know about non-specific vaccine effects? Although Benn and Aaby have contributed about one-third of all research in the area, others have also studied the question, and this should be included to form a complete picture.

 Henrik Støvring et al, What is actually the emerging evidence about non-specific vaccine effects in randomized trials from the Bandim Health Project?, Vaccine (2025). DOI: 10.1016/j.vaccine.2025.127937

Part 2

**

Comment by Dr. Krishna Kumari Challa on Friday

Randomized trials show no evidence of non-specific vaccine effects

Researchers  have conducted randomized trials involving thousands of children in Guinea-Bissau and Denmark to demonstrate so-called non-specific vaccine effects—that is, whether vaccines also protect against diseases other than the one they are designed to prevent.

A new comprehensive Danish review now shows that the trials have been unable to demonstrate non-specific effects for the widely used vaccinations against measles, tuberculosis, diphtheria, tetanus, and whooping cough. The study has just been published in the journal Vaccine.

It is concerning that such a prominent research group has conducted so many randomized trials over such a long period without finding real results. Randomized trials are normally considered the gold standard in medical research, so if they do not show anything, one should be very cautious about presenting it as convincing evidence.

The new study is the first to systematically analyze all of Benn and Aaby's randomized trials. While others have previously criticized individual studies, the researchers behind the new review examined the full body of work.

Researchers find indications that the researchers systematically selected and highlighted results that supported their theories, while downplaying the fact that they did not confirm the primary hypothesis the trials were actually designed to test. When you look at the overall picture, there are almost no real findings left.

The results meant it was time to change the global approach to vaccination—all new vaccines should routinely be assessed for non-specific effects, and vaccination programs should be revised worldwide.

Part 1

Comment by Dr. Krishna Kumari Challa on Friday

Hitler's DNA reveals possible genetic disorder tied to sexual and social behaviour

Adolf Hitler most likely suffered from the genetic condition Kallmann Syndrome that can manifest itself in undescended testicles and a micropenis, researchers  said this week, following DNA testing of the Nazi dictator's blood.

The new research also quashes the suggestion that Hitler had Jewish ancestry.

Popular World War II songs often mocked Hitler's anatomy but lacked any scientific basis.

The findings by an international team of scientists and historians now appear to confirm longstanding suspicions around his sexual development.

No one has ever really been able to explain why Hitler was so uncomfortable around women throughout his life, or why he probably never entered into intimate relations with women.

But now we know that he had Kallmann Syndrome, this could be the answer we've been looking for, say the researchers.

The research findings are featured in a new documentary, "Hitler's DNA: Blueprint of a Dictator." 

The testing found a "high likelihood" that Hitler had Kallmann Syndrome and "very high" scores—in the top one percent—for a predisposition to autism, schizophrenia and biopolar disorder. 

The research team stressed that such conditions, however, could not explain or excuse Hitler's warmongering or racist policies.

The testing was made possible after researchers obtained a sample of Hitler's blood from a piece of material taken from the sofa on which he shot himself.

The DNA results additionally rule out the possibility that Hitler had a Jewish grandfather via his grandmother.

Source: AFP

**

Comment by Dr. Krishna Kumari Challa on Friday

Testosterone in body odor linked to perceptions of social status 

As humans, we are constantly navigating social status, using subconscious strategies to assert either our dominance or prestige.

We often use voice or  body language to communicate this. Imagine a politician with a slow, booming voice, expanding their chest and extending their arms, quickly asserting authority over their audience.

We also use our sense of smell, according to new research from the University of Victoria (UVic), published in Evolution and Human Behaviour.

This study examines the role of body odor in people's perceptions of others' social status. 

Researchers examined whether scent cues associated with levels of circulating testosterone impact people's social status judgments. They found that both male and female participants in their study perceived men with higher levels of testosterone to be more dominant than men with lower testosterone levels.

Chemical signaling is the most widespread form of communication on Earth. Many animals will use scent to express and understand social status within their group. Mice, for example, scent-mark their territory to assert their dominance.

Previous research shows that humans use two different strategies to assert and maintain social status: dominance and prestige. Dominance is coercive, using tactics to force compliance. Prestige, on the other hand, involves showing valuable skills and traits that lead others to show deference voluntarily.

Research also reveals that scent plays an important role in human communication—of fear, sickness, safety, attraction, and personality traits such as dominance and neuroticism.

This is the first study to directly examine whether humans use scent cues related to circulating testosterone levels in the formation of social status judgments.

No significant relationship was found in the study between testosterone levels and perceived prestige. Perceptions of dominance, on the other hand, were associated with higher testosterone levels.

This study contributes to a growing body of work seeking to understand how social communication occurs through scent. 

However, the findings should be interpreted with caution. The study involved a relatively small and uniform sample, and replication with larger and more diverse groups will be important to confirm whether these patterns hold.

Marlise K. Hofer et al, The role of testosterone in odor-based perceptions of social status, Evolution and Human Behavior (2025). DOI: 10.1016/j.evolhumbehav.2025.106752

**

Comment by Dr. Krishna Kumari Challa on Friday

How chromosomes separate accurately: Molecular 'scissors' caught in action

Cell division is a process of remarkable precision: during each cycle, the genetic material must be evenly distributed between the two daughter cells. To achieve this, duplicated chromosomes, known as sister chromatids, are temporarily linked by cohesin—a ring-shaped protein complex that holds them together until separation.

Researchers have uncovered the mechanism by which separase—the molecular ''scissors'' responsible for this cleavage—recognizes and cuts cohesin.

Their findings, published in Science Advances, shed new light on chromosome segregation errors that can lead to certain forms of cancer.

Before a cell divides, its chromosomes are duplicated. These identical copies, called sister chromatids, are held together by cohesin—a ring-like structure composed of several proteins that prevents premature separation.

When the cell is ready to divide, separase, a specialized enzyme, cleaves one of the cohesin subunits, the protein SCC1, allowing the chromatids to separate and the genetic material to be evenly distributed between the two daughter cells. Any malfunction in this process can compromise genome stability, potentially resulting in severe diseases, including cancer.

Using cryo-electron microscopy (cryo-EM)—a cutting-edge technique that enables biological samples to be visualized in their native state at near-atomic resolution—the team captured the interaction between separase and SCC1 and identified the precise cleavage sites on the protein.

Biochemical and structural analyses also revealed multiple "docking sites" on the surface of separase, ensuring high-affinity binding of SCC1 to separase prior to cleavage. These contact points include five phosphate-binding sites that recognize phosphorylated residues on SCC1.

These affinity experiments showed that these phosphate–separase interactions stabilize the complex and accelerate SCC1 cleavage, ensuring fast and precise separation of chromosomes.

The work provides an extensive functional and structural framework to understand how separase is regulated and how it recognizes its substrates.

Jun Yu et al, Substrate recognition by human separase, Science Advances (2025). DOI: 10.1126/sciadv.ady9807

• ‹ Previous
• 1
• 2
• 3
• …
• 1143
• Next ›
• Page