Passive human structures like roads and settlements sometimes reduced animal vigilance, an Indian Institute of Science release said. File
| Photo Credit: The Hindu

Long believed to be inactive or vestigial, scientists believe that the muscles behind the human ear are actually activated when people listen intently, according to a study published in the Frontiers in Neuroscience. This muscle, known as the auricularis posterior, has been largely dormant in humans for centuries but shows signs of reactivation when individuals focus on challenging auditory tasks.

“There are three large muscles [that] connect the auricle [the outer ear] to the skull and scalp. These muscles, particularly the superior auricular muscle, exhibit increased activity during effortful listening tasks,” said first author Andreas Schroer of Saarland University in Germany.

For the study, 20 participants without any hearing problems were recruited and the electrical activity in their auricular muscles was recorded using electromyography as an audiobook along with distracting podcasts in front of or behind them was played.

“Three different conditions, each more difficult and requiring a higher amount of effortful listening, were generated by varying the number and pitch of distractor streams, as well as the signal-to-noise ratio,” the study highlighted.

As the difficulty level of the task increased, so, too did the activity of the superior auricular muscles. Though they remained relatively inactive during the easy and medium trials, the difficult trials saw a surge in their activity.

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Study findings

The study results implied that muscle might be involved in enhancing auditory perception under specific conditions, possibly by subtly adjusting the ear’s position to better capture sound.

The researchers stated that the findings could also help us understand or develop treatments for auditory processing disorders where such muscle activity could be either lacking or excessive.

“It could be worthwhile to explore auricular muscle activity to potentially be used as an objective metric to assess the effectiveness of hearing aid algorithms to reduce listening effort, as there is a clear physiological connection between the pinna and auditory perception.”

Although it is unknown why these muscles became vestigial over 25 million years ago, researchers posit that “evolutionary pressure to move the ears ceased because we became much more proficient with our visual and vocal systems”.

A new study has found that the X chromosome passed down to the child from the mother might be responsible for accelerated brain ageing, potentially increasing the risk of conditions like Alzheimer’s disease. Only females have two X chromosomes (XX) while males have one X and one Y (XY). Given the natural order, the X chromosome carries a significant amount of genetic material, and any mutation or variation here can have profound effects, especially as one X chromosome in females is randomly inactivated in each cell.

Though women tend to live longer than men and have lower rates of dementia, one exception is Alzheimer’s disease which affects them at higher rates. Even then, some studies suggest that females survive longer with Alzheimer’s than males do. The researchers set out to find the reason and believed that the sex chromosomes, X and Y, could help explain the differences.

“Skewing of the X chromosome is common among humans, and there are certainly women who are walking around with much higher or lower levels of maternal X chromosomes than others, just by chance,” said Dena Dubal, senior author of the paper.

“There has been little research on the potential consequences of this,” she added.

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‘The experiment’

To further explore the idea, the researchers experimented with female lab mice of different ages. In some cases, the paternal X chromosomes were silenced, leaving only the mother’s X active. These mice were compared with others that had a mix of maternal and paternal X’s switched on.

As per the findings, the young “Mom-X” mice were cognitively similar to young mice but the older ones showed steep cognitive decline. In the brains of these mice, the maternal X chromosome sped up biological ageing in the hippocampus – a brain area crucial for learning and memory.

“These findings raise the possibility that some women who express more of their mom’s X chromosome just by pure chance may have more cognitive impairment with aging or an increased risk for diseases like Alzheimer’s,” said Ms Dubal.

“Ultimately, it could also help us find constructive strategies for slowing brain aging in both sexes.”

Though the research was conducted on mice, the findings, if they translate to humans, could point to drivers of cognitive decline related to a particular sex and, eventually, help us fund ways to prevent or treat them.

China has conducted another major nuclear fusion experiment in its pursuit of creating a novel source of energy. The Experimental Advanced Superconducting Tokamak (EAST) fusion energy reactor, dubbed China’s ‘artificial sun’ sustained plasma for a whopping 1,000 seconds, breaking the 403-second record it set in 2023, according to a report in Live Science, citing Chinese media reports.

Developing nuclear fusion for energy requirements has long been a goal of scientists but reaching temperatures over 100 million degrees Celsius and sustaining its long-term operation has always proved a challenge. However, by stabilising the system for 1,000 seconds, scientists believe a major milestone in the quest to improve the technology had been achieved.

“A fusion device must achieve stable operation at high efficiency for thousands of seconds to enable the self-sustaining circulation of plasma, which is critical for the continuous power generation of future fusion plants,” Song Yuntao, director of the Institute of Plasma Physics under the Chinese Academy of Sciences, told Chinese state media.

“We hope to expand international collaboration via EAST and bring fusion energy into practical use for humanity,” added Mr Song.

The nuclear reactor is yet to achieve ignition which is the point at which nuclear fusion creates its own energy and sustains the reactions. However, the new record is an encouraging step towards maintaining prolonged, confined plasma loops that may power future reactors.

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EAST and nuclear fusion

Chinese scientists have been operating EAST since 2006 with the reactor completing hundreds of thousands of tests so far. Buoyed by the success of EAST, China has already started the construction of a new generation of experimental fusion research facilities in east China’s Anhui Province, aiming to further accelerate the application and development of fusion energy.

Scientists regard nuclear fusion as the holy grail of energy. It is what powers our Sun as atomic nuclei are merged to create massive amounts of energy, which is the opposite of the fission process used in atomic weapons and nuclear power plants, where the heavy atom is split into multiple smaller ones.

Unlike fission, fusion emits no greenhouse gases and carries less risk of accidents or the theft of atomic material. By mimicking the natural reaction of the sun, scientists are hoping that the technology may help harness near-unlimited amounts of energy and help battle the energy crisis as well as power humanity’s exploration beyond the solar system.

Black holes are among the most mysterious cosmic objects, much studied but not fully understood. In pursuit of understanding these celestial bodies, astronomers have stumbled upon a supermassive black hole, located a whopping 12.9 billion light-years from Earth, and it’s doing something pretty spectacular. The “blazar” is firing a super-powerful beam of energy straight towards us.

The energy beam from this black hole has travelled to us, just over 100 million years after the Big Bang took place — setting a new record for the distance from which we’ve observed such a phenomenon. The discovery also raises questions about how supermassive black holes grow so rapidly in the Universe’s infancy.

Named J0410-0139, the black hole has a mass of about 700 million Suns and is one of the oldest of its kind that scientists have ever observed. Detected using data from several telescopes, including NASA’s Chandra Observatory and Chile’s Very Large Telescope, the black hole has provided a new peek into the early universe.

“The alignment of J0410-0139’s jet with our line of sight allows astronomers to peer directly into the heart of this cosmic powerhouse. This blazar offers a unique laboratory to study the interplay between jets, black holes, and their environments during one of the Universe’s most transformative epochs,” said Dr Emmanuel Momjian, an astronomer at the National Radio Astronomy Observatory in Virginia, associated with the study, published in The Astrophysical Journal Letters.

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What is a blazar?

The universe is full of powerful supermassive black holes that create powerful jets of high-energy particles, creating sources of extreme brightness in the vastness of space. When one of those jets points directly at Earth, scientists call the black hole system a blazar, as per NASA.

The jets extending from these blazars can extend millions of light-years in length. They are exceedingly bright because as particles approach the speed of light, they give off a tremendous amount of energy and behave in weird ways that Albert Einstein predicted.

Up until now, a little less than 3,000 blazars have been discovered but most are located closer to Earth than J0410-0139. Despite decades of study, scientists still don’t fully grasp the physical processes that shape the dynamics and emission of blazar jets.

For the first time, scientists have quantified how quickly the human brain is able to process any information and the results might not be as flattering as we might have previously believed. According to the researchers, humans process information at a speed of just 10 bits per second despite receiving billions of bits of information that our senses, including the eyes, ears, skin, and nose gather cumulatively.

Notably, a bit is the basic unit of information in computing with a typical Wi-Fi connection processing about 50 million bits per second. Scientists found that during activities such as reading, writing, playing video games, and solving Rubik’s cube, humans can only think at a speed of 10 bits per second, which they called “extremely slow”.

Scientists at the California Institute of Technology set out to discover the reason for this paradox and published their findings in the journal Neuron last week.

“This is an extremely low number. Every moment, we are extracting just 10 bits from the trillion that our senses are taking in and using those 10 to perceive the world around us and make decisions. This raises a paradox: What is the brain doing to filter all of this information?” said neurobiologist Markus Meister who was involved in the study.

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What’s the reason?

Although there is no clear answer, the researchers posited that our slow brain processing might be down to necessity, or rather, the lack of it.

“Our ancestors have chosen an ecological niche where the world is slow enough to make survival possible,” the study noted. “In fact, the 10 bits per second are needed only in worst-case situations, and most of the time our environment changes at a much more leisurely pace.”

Based on the research, the scientists said there was a need for more research into how our brain only focuses on one train of thought at a time, instead of capitalising on the sea of information it receives every passing second.

“The current understanding is not commensurate with the enormous processing resources available, and we have seen no viable proposal for what would create a neural bottleneck that forces single-strand operation,” the researchers added.

Further exploration is needed as there are over 85 billion neurons with one-third of these dedicated to high-level thinking and located in the cortex.

Scientists have discovered that future robots might be able to gauge how you are feeling by just touching human skin. According to a new study published in the journal IEEE Access, researchers used skin conductance as a way to figure out how an individual was feeling. Skin conductance is a measure of how well skin conducts electricity, which usually changes in response to sweat secretion and nerve activity, signifying different human emotional states.

Traditional emotion-detection technologies such as facial recognition and speech analysis, are often prone to error, especially in suboptimal audio-visual conditions. However, scientists believe that skin conductance offers a potential workaround, providing a non-invasive way to capture emotion in real-time.

For the study, the emotional responses of 33 participants were measured by showing them emotionally evocative videos and measuring their skin conductance. The findings revealed distinct patterns for different emotions: fear responses were the longest-lasting, suggesting an evolutionary alert mechanism; family bonding emotions, a blend of happiness and sadness, showed slower responses; and humour triggered quick but fleeting reactions.

“To date, few studies have examined how the dynamics of skin conductance responses differ among emotions, despite high responsiveness being a key feature of skin conductance,” the scientists highlighted.

“The results of this study are expected to contribute to the development of technologies that can be used to accurately estimate emotions, when combined with other physiological signals.”

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Integrating skin conductance with other techniques

The study and the conductance technique rely on the fact that emotional response to any situation triggers the sweat glands, which in turn, alters the skin’s electrical properties. Although the method is far from perfect, scientists argue that integrating it with measures like heart rate and brain activity could refine the accuracy of emotion detection.

“There is a growing demand for techniques to estimate individuals’ subjective experiences based on their physiological signals to provide them with emotionally evocative services,” the scientists wrote in the study.

“Therefore, further exploration of these physiological signals in this study, particularly skin conductance responses, can advance techniques for emotion recognition.”

The study has far-reaching consequences as it could mean that future robots will not be able to just interact but also empathise with human users by understanding their emotional states through subtle physiological cues.

At least 350 elephants died under mysterious circumstances in Botswana in 2020, sparking global concerns while leaving scientists puzzled about the reason for the mortalities. Four years later, a study conducted at King’s College London may have finally unearthed the answer. As per the research, a “toxic brew” of open water tainted by a species of cyanobacteria that releases cyanotoxins, which contaminated the watering holes in the region, led to mass elephant deaths.

Combining satellite data and spatial analysis the study revealed that as many as 20 watering holes in the Okavango Delta had been contaminated across roughly 6,000 sq km. After drinking, elephants were estimated to have walked an average of 16.5 km from the toxic waterholes and died within about 88 hours of exposure.

“Our results highlight that seasonal, predominantly rain-fed pans, rather than the permanent waterbodies (i.e., lakes, rivers, and lagoons) within the Panhandle, were the likely source of cyanotoxin exposure,” said Davide Lomeo, the lead scientist of the study.

Notably, the dead elephants were of varying ages, with tusks intact which led to scientists ruling out death by poaching. Additionally, no carcasses of other wildlife or livestock species were observed at the time of one of the aerial surveys.

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What promoted algae growth?

Not all cyanobacteria or blue-green algae is toxic but some cyanobacteria produce a type of deadly algal blooms (HABs) in standing water. As per the study, the shift from a dry 2019 (the driest year in decades in the region) to an extremely wet 2020, may have prompted the unprecedented algal growth due to the resuspension of significant amounts of sediments and nutrients from the ground.

“Scientists believe that the production of cyanotoxins is related to certain environmental triggers, for example, sudden rise in water temperature, nutrient loading, salinity,” said Mr Lomeo.

Scientists have warned that such incidents may become frequent in the future owing to climate change.

“Southern Africa is projected to become drier and hotter under climate changes, and as a result, waterholes across this region will likely be drier for more months of the year. Our findings point to the potential negative effects on water quantity and quality, and the catastrophic repercussions on animals, this could have.

The study underscores the severe ecological consequences of toxic algal accumulation while emphasising the critical need for water quality surveillance across water bodies, including the smallest ones.

Having higher levels of testosterone does not mean men have a higher sex drive, as previously thought — a new study published in the journal Proceedings of the Royal Society B has claimed. Testosterone is a hormone, produced primarily in the testicles of men and in smaller amounts in the ovaries of women. It plays an important role in the development of male secondary sexual characteristics such as body hair growth, and increased muscle and bone mass. While its role in reproductive behaviour has been significantly documented, an international team of researchers led by the University of California, Santa Barbara believe that day-to-day changes in testosterone levels had no real link to sexual desire in men.

“A man experiencing higher-than-usual testosterone concentrations on a given day does not typically exhibit higher-than-usual sexual desire on that same day,” the study stated.

As per the researchers, their study corroborated with prior findings suggesting that men’s sexual desire requires only a threshold amount of baseline testosterone.

Interestingly, the researchers found that there was a positive relationship between testosterone levels and the degree of effort men put into wooing their significant other.

“We propose that the evolved functions of testosterone in human males are more closely associated with courtship efforts than with sexual desire,” the study highlighted.

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How was the study conducted?

41 men aged 18 to 26 of varying relationship statuses (27 single, 14 committed to a partner) were recruited for a 31-day trial. A daily saliva analysis was taken to measure testosterone concentrations with the participants required to fill answers to questions such as: “How much sexual desire did you experience?” “How much effort did you put into attracting a possible romantic and/or sexual partner yesterday?” and “How much did you have sexual fantasies?”

On days when the single men interacted with prospective partners, testosterone concentrations were higher, suggesting more effort was made to seek out a mate.

“Testosterone fluctuations in the normal range may positively predict day-to-day changes in men’s mate attraction efforts among single men, especially given social interactions with potential mates.”

Despite the findings, the researchers said they needed more data to further develop their understanding of the matter. 

US researchers have discovered what appears to be the oldest known alphabetic writing in the world, after finding finger-length clay cylinders from a tomb in Syria with the etched details. Using carbon-14 dating techniques, the researchers at John Hopkins University determined that the cylinders were made around 2400 B.C.E., which makes them around 500 years older than any other known alphabetic scripts. Alongside the writings, the researchers discovered Early Bronze Age tombs, including a well-preserved grave with six burials inside.

The bodies were accompanied by gold and silver jewellery, cookware, a spearhead, and pottery vessels. Four “lightly baked clay cylinders” were next to the pottery and were etched with alphabetic writing. Notably, they were found in 2004 and described in an academic paper in 2021 but only gained prominence this week as one of the researchers presented the findings at the annual meeting of the American Society of Overseas Research.

“This new discovery shows that people were experimenting with new communication technologies much earlier and in a different location than we had imagined before now,” said Glenn Schwartz, a professor of archaeology at Johns Hopkins University, associated with the research.

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‘Different origin’

Long before alphabet came into existence, human civilisations used different means to communicate. While the Sumerians of Mesopotamia used cuneiforms or small images, the ancient Egyptians developed hieroglyphics, and Chinese characters built the written language piece by piece.

“Previously, scholars thought the alphabet was invented in or around Egypt sometime after 1900 BCE. Our artefacts are older and from a different area on the map, suggesting the alphabet may have an entirely different origin story than we thought,” Mr Schwartz added.

The form of writing, discovered on the clay cylinder may have revolutionised language by making it accessible to people not belonging to the royalty and social elite. However, the scientists have been unable to translate what the writing on the cylinder means.

“The cylinders were perforated, so I’m imagining a string tethering them to another object to act as a label. Maybe they detail the contents of a vessel, or maybe where the vessel came from, or who it belonged to. Without a means to translate the writing, we can only speculate.”