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Comment by Dr. Krishna Kumari Challa on Friday

Moms' learned fear of snakes gets inherited by offspring in a critically endangered mouse, biologists discover

Conservationists often raise the young of endangered species in captivity before releasing them into suitable habitats as adults. The benefits are obvious: survival to adulthood is typically high, as captive animals are safe from predators and food scarcity. Unfortunately, a lack of exposure to enemies in early life may become a drawback later, if the released individuals have never learned to recognize and avoid their predators.
One way to fix this is "antipredator training," where young animals are confronted with fake or real predators and taught to associate these with an unpleasant stimulus. However, this method is labor-intensive and depends on the realism of the training and the ability and most sensitive period for learning of the captive species. But now, researchers may have found a more efficient alternative: train the mothers instead.

Predator training of pregnant Pacific pocket mouse females resulted in their female offspring exhibiting increased vigilance toward snakes, while no such effect was observed in male offspring. No significant improvement in post-release survival was detected, possibly due to limited sample size and pre-release exposure. Maternal effects may be mediated by prenatal programming, postnatal behaviour, or odour cues.

Female offspring of predator-trained mothers were more vigilant during predator encounters, suggesting that maternal experiences may shape offspring behavior in ways that could be useful for conservation breeding and reintroduction programs.
Researchers conducted a randomized controlled experiment with two arms on 22 pregnant females in the second half of gestation. Each trial was filmed and lasted 20 minutes. Half of the females were assigned to the predator-exposed treatment, in which they were placed in a testing arena with food.

After acclimatization, a live kingsnake (a native predator of small mammals) was introduced behind a wire mesh across the arena. Pocket mice were sprayed with water whenever they approached the snake.

The mice received scores for behavior, location, and orientation relative to the snake. The remaining pregnant females were assigned to the control, where the snake was replaced with a rope of similar length. Control females were never sprayed.

Once pups had been born (87 in total) and reached 30 days of age, the scientists tested their behaviour towards a snake following the same protocol. A subset of 44 offspring were then released into suitable habitat within coastal southern California, while their post-release survival was assessed through live trapping towards the end of the summer active season.
The results showed that in the snake's presence, daughters of predator-trained mothers displayed more vigilance behaviours like scanning, freezing, and rearing up to monitor their surroundings and assess potential threats. However, no such difference was found between sons of predator-trained mothers and sons of control mothers.
Part 1

Comment by Dr. Krishna Kumari Challa on Friday

UN report warns AI could soon use 3% of world's electricity and more water than we need to drink

By 2030, AI could consume 3% of global electricity, emit carbon equivalent to the UK, and use more water for cooling than the annual global drinking water requirement. Efficiency improvements may not reduce total resource use due to increased demand, following the Jevons paradox. The report emphasizes the need for responsible AI governance, environmental disclosures, and integration of sustainability into AI development and policy.

original article.

Comment by Dr. Krishna Kumari Challa on Friday

Even years after stroke, spinal cord stimulation could improve arm function

Researchers report the final outcomes of a pioneering pilot clinical trial using electrical stimulation of the spinal cord to improve arm and hand mobility in people with chronic stroke in Nature Medicine.
The study, which was primarily focused on investigating safety and preliminary efficacy, showed that seven participants with profound muscle weakness due to stroke experienced an average 32% increase in arm strength, along with improvement in overall arm mobility and reduction in muscle spasticity.

Importantly, the intervention required fewer than nine hours of movement-based training over four weeks and did not cause discomfort or serious adverse events.

The stimulation works mostly as an assistive technology—when it's on, people can move better. By stimulating the spinal cord, we can immediately allow residual connections between the brain and the spinal cord to work more efficiently, enabling better movement.
Stimulation sends targeted electrical signals to sensory nerve fibers in the spinal cord to enhance communication between the brain and weakened muscles. The same class of device has been used for decades to treat chronic pain, but this is the first time it has been used to restore arm function after stroke.
Researchers observed two distinct types of benefit. Over the four-week study period, all seven research participants experienced immediate improvements in strength when stimulation was turned on, regardless of how severe their impairment was at baseline. Additionally, spasticity—abnormal muscle stiffness caused by stroke-damaged nerve pathways—was reduced in all seven participants.
This approach is designed to rapidly help people move their arms better, even years after a stroke.

Spinal cord stimulation for upper limb motor function in people with chronic post-stroke hemiparesis: a feasibility trial, Nature Medicine (2026). DOI: 10.1038/s41591-026-04435-1

Comment by Dr. Krishna Kumari Challa on Friday

Charred Bronze Age teeth unlock age at death despite cremation

Over 3,000 years ago, the people of Bronze Age Poland burned their dead and placed their ashes in urns, often destroying the intimate records of their lives preserved in their bones. Now, researchers have shown that some of these records can still be read, hidden in the charred roots of their teeth.
The new study, published in Scientific Reports, has shown that microscopic growth lines in teeth may offer a promising alternative to traditional methods, which are often too scrambled or destroyed to provide an age-at-death. Additionally, the researchers made a surprise discovery, finding that growth lines may also provide insights into a person's diet, environment, or some other part of daily life.

"Cremated human remains are often considered extremely difficult to study because fire changes the structure of bones and teeth so dramatically. Scientists now accepted this challenge.
As the tooth root grows, it leaves behind alternating dark and light lines that researchers can use to estimate age at death.
To test whether these lines persisted in ancient cremated remains, the team examined 62 tooth roots from across Poland's Lusatian Urnfield culture, which existed during the Late Bronze and Early Iron Age, roughly 3,300 to 2,500 years ago.

The name 'Urnfield' comes from the widespread practice of cremating the dead and burying their ashes in ceramic urns gathered in large cemeteries, sometimes containing hundreds or even thousands of graves.
For the Lusatian Urnfield culture, cremation was not just common, it was near universal. This makes intact bodies extremely rare, forcing researchers to rely on the broken and burned cremated bones, which often leave unanswered questions.
The researchers sliced the teeth into paper-thin sections for microscopic examination. They then had two researchers count the lines and compare them to surviving alternative age estimates. Not only did the tooth-based estimates align with traditional methods, but they also pinpointed the age to a much narrower timeframe.

Intriguingly, the researchers also noticed the line thickness varied. While previous researchers had suggested this may be the result of differences between males and females, the study authors found the width was likely related to geographic region.

It is possible these differences are related to different environments, diets, or other aspects of daily life that may have affected the teeth. However, the researchers are careful to note that the findings are preliminary.

Agata Hałuszko et al, Methodological validation and inter-site analysis in Late Bronze and Early Iron Age cremations using tooth cementum annulation counts, Scientific Reports (2026). DOI: 10.1038/s41598-026-51841-z

Comment by Dr. Krishna Kumari Challa on Friday

The results of the team's experiments suggest that when people watch short videos, they do not remember the information presented to them as well as they would when watching longer videos. In addition, the researchers found that while their study participants were watching short videos, brain regions involved in attention, episodic memory (i.e., memory of events or facts) and cognitive control (i.e., the control of mental functions) were less synchronized.

In contrast, they recorded a greater synchrony between brain regions linked to a focus on external stimuli. Collectively, these observations suggest that the disjointed and rapidly changing quality of short videos interferes with the deep processing of information, making it harder for viewers to memorize contained information or acquire new knowledge.
Together, these findings suggest that the fragmented and rapidly switching nature of typical social media short videos enhances bottom-up attentional capture at the expense of top-down cognitive processes critical for deep learning and long-term memory consolidation," wrote the authors. "This study provides converging neurobehavioral evidence suggesting that SVs viewing in social media contexts is associated with reduced neural synchronization and poorer memory performance."

Meiting Wei et al, Learning via short videos impairs memory accuracy and reduces brain synchrony, Communications Psychology (2026). DOI: 10.1038/s44271-026-00476-x

Part 2

Comment by Dr. Krishna Kumari Challa on Friday

Short videos may hinder learning by fragmenting attention and memory, study finds

Recent technological advances and the introduction of new digital media platforms have dramatically changed how people learn and source information about topics that interest them. Some recent studies have found that while browsing online or scrolling down social media platforms, users tend to spend under one minute on average on individual videos.

Short videos that summarize concepts have thus become increasingly popular among online content creators. More recently, they have also made their way into some educational settings, yet the extent to which they can support learning and help students memorize information remains unclear.

Researchers recently set out to assess the potential of short videos and longer videos as learning resources. Their findings, published in Communications Psychology, suggest that short videos are significantly less effective learning tools than longer videos, as people tend to rapidly forget the information presented in them.

The rapid rise of short videos, particularly social media-style formats characterized by rapid switching and fragmented content, has led to their increasing integration into learning environments, wrote the researchers in their paper, but  their efficacy and neurocognitive impact remain contentious.

The researchers carried out three separate experiments involving over 150 college students. 

The videos that participants watched were either 10 minutes long or spanned between 30 seconds and two and a half minutes. In addition, some participants were explicitly asked to memorize the content of the video, while others were not.

"Across three experiments, memory performance and forgetting rate were assessed under both incidental and intentional encoding conditions, and inter-subject correlation (ISC) analysis was employed to investigate neural response patterns during short video viewing," wrote the authors. "Behaviourally, participants learning with short videos showed significantly lower immediate memory accuracy across encoding conditions and exhibited a higher rate of forgetting when explicitly instructed to remember."

Notably, the study participants watched videos inside a functional magnetic resonance imaging (fMRI) scanner, a machine that maps activity in the brain by tracking changes in blood flow. The research team later analyzed the fMRI scans they collected and tried to uncover neural activity patterns associated with viewing short and long videos.

"At the neural level, ISC analyses revealed that short videos elicited reduced neural synchrony in key brain regions supporting visuospatial attention, episodic memory, and cognitive control, including the superior parietal lobule, precuneus, and middle occipital gyrus," wrote the researchers. "In contrast, short videos evoked higher synchrony in temporal and frontal regions associated with bottom-up attentional processing. Furthermore, functional connectivity analyses indicated that SVs weakened coupling between visual, attentional, and cognitive control networks."

Part 1

Comment by Dr. Krishna Kumari Challa on Wednesday

Older brains work harder to stay upright, with nearly 50% longer delay

Aging is known to degrade sensory systems, posing a major challenge to balance control and resulting in an increased risk of falls.
Researchers  have shed light on the brain mechanisms underlying age-related changes in postural control. Using a novel approach, the researchers discovered that older brains must work significantly harder than younger ones to process sensory information and control movement, alongside a substantial processing delay.

Older adults exhibit significantly increased brain activity and nearly 50% longer processing delays when maintaining balance compared to younger individuals. This heightened neural effort is closely linked to greater postural instability and is not solely explained by vestibular decline, indicating that aging brains require more active control to maintain upright posture.

The study demonstrated that when older adults try to stay balanced, their brain activity syncs up closely with how much they wobble, especially in difficult balancing situations—and those who wobble the most have the highest brain activity.
This means that older adults have to actively maintain their balance, using parts of their brain to stay upright. Younger people, on the other hand, stay balanced automatically without having to think about it or use up mental energy.

Furthermore, it takes significantly longer for an older person's brain to process balance information, almost 50% longer. Interestingly, even though many older participants showed inner-ear decline, this wasn't the reason their brains were working so much harder.

Ultimately, this research helps us understand how the aging brain controls balance, and it opens the door for future studies in medicine and neuroscience to help predict and hopefully prevent fall risks in older adults.

Thomas Legrand et al, Aging increases the cortical resources allocated to static balance maintenance, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2524894123

Comment by Dr. Krishna Kumari Challa on Wednesday

Ebola may have spread beyond Africa. How are health authorities responding?
The current Ebola outbreak, caused by the Bundibugyo strain, has resulted in over 900 suspected cases and 223 deaths in the DRC, with limited spread to Uganda and suspected but unconfirmed cases in Italy and Brazil. International health authorities have declared a public health emergency, implemented travel restrictions, and activated safety protocols. Vaccine development is being accelerated, but the risk of global spread remains low with current containment measures.

Similar to the West African outbreak, this latest Ebola outbreak has spread to other continents through travel.

Nine cases and one death have already been reported in Uganda, which shares a border with the DRC.

An American man who tested positive for Ebola while working in the DRC, is in a stable condition after being treated in Germany.

In Italy, authorities are monitoring a traveler who recently returned from the DRC to the city of Cagliari.

According to some reports, Brazilian authorities are investigating two suspected Ebola cases. They are believed to be two travelers, one who returned from the DRC to São Paulo and the other from Uganda to Rio de Janeiro.

Importantly, both suspected cases have been diagnosed with other illnesses. The São Paulo patient presented with fever and was later diagnosed with severe meningitis. The Rio de Janeiro patient tested positive for malaria after developing a cough, chills and diarrhea, but has since tested negative for Ebola.

So for now, no Ebola cases have been confirmed in Brazil. But these suspected cases have prompted the country to activate its Ebola safety protocols, including patient isolation, laboratory testing, and epidemiological investigations.

Meanwhile, several countries have imposed travel restrictions to prevent Ebola from reaching their shores.

original article.

Comment by Dr. Krishna Kumari Challa on Wednesday

These sounds have long wavelengths that can travel over great distances.

The first thing the researchers did was test whether the participants had particularly good hearing for low-frequency sounds that are actually known to exist.

Most did not, except for two participants who had better hearing than average at certain low frequencies.
It still means that the hypothesis of having especially good hearing for low-frequency sounds does not hold for most people.
There are differences in hearing thresholds (microstructures) that make it possible for some people to hear sensitively in a very narrow frequency range, for example between 50 and 51 Hertz. These nuances are not captured by conventional hearing tests.
The ear can produce sounds itself
The cochlea in the inner ear itself produces weak sounds with different frequencies, typically between about 500 and 5000 Hertz. These sounds have no function of their own, but are a by-product of a physiological sound amplification process.

Most of us don't hear these sounds. However, a few people can actually hear the sounds that the ear itself produces. And these sounds can be measured objectively
These particular sounds are called oto-acoustic emissions and can be detected by placing a sensitive microphone in the ear canal. In some people, these spontaneous oto-acoustic emissions can be experienced as troublesome tinnitus.

"One hypothesis was that the participants in our group could hear oto-acoustic emissions at low frequencies.
But… the answer was no.
Sounds that cannot be measured
"Then there are people who hear something that cannot be measured objectively.
Tinnitus or ringing in the ears is when you hear a sound in the ear or in the head, which is not caused by an external sound source.

Many people experience tinnitus, either permanently or for shorter periods. These individuals first experience the sounds in their ears as a sound coming from outside.

But as the sound persists, even when they move to other places, they gradually become aware that the source of the sound is not external.
based on what is known about hearing and the tests they conducted on study participants, the best explanation is twofold.

A few people who hear the hum actually have particularly good low-frequency hearing. However, for most people, it may be a form of tinnitus, meaning a sound that originates from inside the auditory system.
Based on the results, although the researchers haven't ruled out cases of physical external sound sources, they suggest that subjective tinnitus in the low-frequency range is often the cause of hearing pulsations of low-frequency sound perceptions.

Bonifaz Baumann et al, On the potential sources of a low-frequency sound percept that only a few can perceive, PLOS One (2026). DOI: 10.1371/journal.pone.0326818

Part 3

Comment by Dr. Krishna Kumari Challa on Wednesday

Many different theories have been offered to explain the cause of the phenomenon; everything from acoustic pollution from human-made sources to sounds that nature itself makes—as well as conspiracy theories that the sound is produced by the CIA or even aliens.

There are many human sources of low-frequency sound. These can include ventilation systems, heat pumps, traffic noise, windmills and more. Examples of natural sources include the sounds of waves crashing along the coast and wind sweeping through the landscape.

The hum has attracted the interest of hearing and audiology researchers worldwide.
Other explanations for 'the hum'
Military aircraft and submarines
One theory that has been proposed is that the hum relates to sound waves from US military aircraft that use radio frequencies at the lowest end of the spectrum of sound frequencies to communicate with submarines. These aircraft operate at night, and their movements are top secret. The theory may also explain why many "hum sites" are located on the coast.

Amorous fish
The Scottish Association for Marine Science has suggested that the noise in the UK coastal town of Hythe could be caused by the mating call of schools of male plainfin midshipman fish (Porichthys notatus). Amorous male fish make loud sounds, sometimes for hours, to attract females.

Waves, volcanic eruptions, or lightning strikes
In 2015, French researchers suggested that the hum was caused by waves moving along the seafloor. When the waves collide with ridges on the continental shelves, it creates vibrations that are audible to some.

Other researchers have suggested that vibrations caused by volcanic eruptions and earthquakes could be the cause.

Yet another theory points to the lightning strikes that strike Earth every day. Lightning strikes build up a massive electromagnetic charge that creates a resonance between Earth's surface and the ionosphere—much like blowing air over the top of a bottle.

Sensitive brains
Dr. David Baguley, head of the audiology department at Addenbrooke's Hospital in England, has done extensive research into the phenomenon. He believes it is due to sensitive brains that can pick up ultra-low sound frequencies.

He pointed out that our sense of hearing is greatly affected if we experience a lot of stress, and the brain turns up the volume to detect threatening sounds.

Sounds that can be measured
The researchers tested two hypotheses.

One was that the hum can be measured, both from human-made infrastructure and industry and also from nature itself, which creates low-frequency sounds.

Part 2

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