A mysterious object discovered in the Milky Way

Barr DE et al. A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes. Science, January 2024.

Astronomers using the MeerKAT Radio Telescope have made a groundbreaking discovery in the Milky Way—a mysterious object with a mass greater than the heaviest neutron star yet lighter than the smallest black hole. The object, identified near a rapidly spinning neutron star or millisecond pulsar called PSR J0514-4002E, was found within a dense globular cluster of stars about 40,000 light-years away. The MeerKAT, equipped with 64 antennas in South Africa, detected the dense stellar remnant. If the companion was a black hole, it would have formed a coveted radio pulsar-black hole binary system, offering a unique opportunity to test Einstein’s theory of gravity. The pulsar, rotating at an astonishing 170 times per second, was observed through faint radio waves. Changes in its regular pulses revealed an orbiting object with incredible density, likely the remnant of a massive collapsed star. The pulsar and the mystery object orbit each other every seven Earth days at a distance of 5 million miles, falling within the black hole mass gap. Neutron stars and black holes are born when massive stars exhaust their nuclear fusion fuel. The collapse of the star’s core leads to the formation of neutron stars or black holes. The newly discovered object challenges the existing understanding of the black hole mass gap, as it has more mass than any known neutron star but less than any known black hole.

The researchers propose that the object may have been created through a collision between two neutron stars in the crowded globular cluster NGC 1851. However, the nature of the companion—whether it’s a neutron star, black hole, or a previously unidentified cosmic object—remains unknown. The newly discovered system serves as a unique cosmic laboratory, offering insights into extreme conditions and promising a turning point in our understanding of neutron stars, black holes, and the enigmatic black hole mass gap. This discovery opens new avenues for studying the behavior of matter and physics in the universe’s most extreme environments.

Dietary restriction slows brain aging and extends lifespan

Wilson KA et al. OXR1 maintains the retromer to delay brain aging under dietary restriction. Nature Communications, January 2024.

Scientists have discovered a crucial link between caloric restriction and healthy brain aging, shedding light on the mechanisms behind the positive effects of limiting calorie intake on lifespan and brain health. While dietary restriction is known to enhance health and longevity, its impact on the brain has been less understood until now. This new study identifies the OXR1 gene as essential for the lifespan extension associated with dietary restriction and for promoting healthy brain aging. The study, conducted in fruit flies and human cells, unveils a detailed cellular mechanism through which caloric restriction can delay aging and slow the progression of neurodegenerative diseases. The team found that the OXR1 gene generates a neuron-specific response that mediates the neuroprotection observed with dietary restriction. Strategies like intermittent fasting or caloric restriction, which limit nutrients, may boost levels of the OXR1 gene, thus exerting protective effects on the brain. OXR1 protects cells from oxidative damage, and its loss in humans leads to severe neurological defects and premature death. The research delved further into the retromer, a protein complex crucial for recycling proteins and lipids in cells. OXR1 was found to influence the retromer, preserving its function and playing a key role in protecting neurons during dietary restriction. Dysfunction in the retromer has been linked to age-related neurodegenerative diseases such as Alzheimer’s and Parkinson’s. By understanding the connection between OXR1, dietary restriction, and brain health, the study provides insights into why individuals respond differently to diets and opens avenues for potential therapeutic targets to slow aging and age-related neurodegenerative diseases. Overall, the findings suggest that a healthy diet has a profound impact on various bodily processes, supporting efforts to follow dietary practices that positively influence overall health and longevity.

Unraveling Human Memory and Imagination Using Generative AI

Spens and Burgess. A generative model of memory construction and consolidation. Nature Human Behavior, January 2024.

Human memory plays critical roles in diverse cognitive processes, contributing significantly to our capacity to learn about the world, remember about past experiences, and generate entirely new scenarios for imagination and planning. A recent study introduces an AI (Artificial Intelligence) computational model – also known as a generative neural network — to simulate how neural networks in the human brain reconstructs past events and imagines new scenarios.

The model features networks representing the hippocampus and neocortex, the parts of the brain that are known to work together during memory, imagination, and planning, to investigate how they interact. The hippocampus is instrumental in memory formation and spatial navigation, while the neocortex is associated with computations related to attention, thought, perception, and episodic memory. Researchers exposed the model to 10,000 images, enabling rapid encoding of scenes by the hippocampal network. Subsequently, the generative neural network in the neocortex was trained by replaying scenes. Analyses showed that the hippocampus rapidly absorbed scenes and replayed them, instructing the neocortex through repetitive exposure. The neocortex, in response, learned to reconstruct scenes by organizing information, focusing on crucial elements like the arrangement of walls and objects. This efficiency allows the brain to remember scenes and generate novel ones without storing every minute detail.

Research suggests that replaying memories during rest helps the brain discern patterns from past experiences, aiding in future predictions, such as avoiding dangers or locating food. This study explains how the brain generates new events during imagination and future planning, highlighting the role of memory reconstruction in these processes. It also provides insights into why existing memories often exhibit distortions, where unique features are generalized and remembered more in line with features from previous events.

Plant-based diet promotes rapid heart benefits

Landry MJ et al. Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins. JAMA Network Open, November 2023.

A vegan diet has been shown to significantly improve cardiovascular health in just eight weeks. A recent study utilized twenty-two pairs of identical twins to control for genetic differences and other confounding factors, as the twins shared similar upbringings and lifestyles. The trial involved forty-four participants, with one twin from each pair following a vegan diet and the other an omnivore diet. Both diets were considered healthy, rich in vegetables, legumes, fruits, and whole grains, while excluding sugars and refined starches. The vegan diet was entirely plant-based, excluding meat, eggs, and dairy, while the omnivore diet included animal-sourced foods. Results showed significant improvements in cardiovascular health for those on the vegan diet. Participants following the plant-based diet exhibited lower levels of low-density lipoprotein cholesterol (LDL-C), insulin, and body weight compared to their omnivore counterparts. The vegan participants also experienced a 20 percent drop in fasting insulin levels and lost an average of 4.2 pounds more than their omnivore counterparts. The most substantial changes occurred within the first four weeks, suggesting rapid benefits from adopting a vegan lifestyle. This study emphasizes the potential benefits of moving toward a more plant-based diet, even if not fully vegan. Cutting back on saturated fats, increasing dietary fiber, and losing weight—achieved by both vegan and omnivore participants—are key steps for improving cardiovascular health. Incorporating more plant-based foods into one’s diet, citing additional benefits such as increased gut bacteria and reduced telomere loss, contributing to slowed aging.

Tiny biobots heal damaged cells

Gumuskaya et al. Motile Living Biobots Self‐Construct from Adult Human Somatic Progenitor Seed Cells. Advanced Science, November 2023.

Scientists have developed anthrobots—tiny robots made of human cells capable of repairing damaged neural tissue. Unlike previous prototypes generated from animal cells, these anthrobots were constructed using human tracheal cells, opening up possibilities for personalized medicine. The anthrobots were produced by growing spheroids of human tracheal skin cells in a gel for two weeks, then transferring them to a less viscous solution for an additional week. This process caused cilia, tiny hairs on the cells, to move to the exterior of the spheroids, enabling them to function as oars. The resulting anthrobots, consisting of a few hundred cells each, displayed various swimming patterns, including straight lines, circles, arcs, and chaotic movements. To assess their therapeutic potential, researchers placed several anthrobots in a dish, where they fused together to form a “superbot.” This superbot was then placed on a layer of neural tissue that had been intentionally scratched. Remarkably, within three days, the sheet of neurons had completely healed under the influence of the superbot.

Going forward, the researchers envision using anthrobots made from an individual’s own tissue for applications such as clearing arteries, breaking up mucus, or delivering drugs. By exploring different cell types and stimuli, the development of biobots—robots composed of biological material—with applications in sustainable construction and space exploration becomes a conceivable future possibility. The ultimate goal in these efforts is to utilize biobots in regenerative medicine, potentially leading to advancements like limb regrowth.

Music preferences mirrors ethical compass

Preniqi V et al. Soundscapes of morality: Linking music preferences and moral values through lyrics and audio. PLOS ONE, November 2023.

A recent study discovered a striking connection between musical preferences and an individual’s moral compass. Utilizing machine learning to analyze the audio and lyrical content of songs, scientists examined 1,400 participants who disclosed their favorite artists and songs. Psychometric questionnaires in parallel assessed participants’ moral values, focusing on character traits such as Care, Fairness, Loyalty, Authority, and Purity. The study revealed that specific musical elements, such as pitch and timbre, correlated closely with values of Care and Fairness, while sentiments and emotions expressed in lyrics were effective in predicting traits related to Loyalty, Authority, and Purity. Those valuing care and empathy were drawn to songs emphasizing compassion and understanding, while proponents of fairness and justice gravitated toward music addressing social issues or advocating for equal rights. Individuals emphasizing loyalty and patriotism enjoyed songs celebrating national pride and collective identity. People who value care and fairness may prefer softer, melodic, and less aggressive music, while those with a higher emphasis on authority and tradition might lean towards more structured and possibly classical forms of music. A preference for energetic and upbeat music with positive, uplifting lyrics may indicate an individual’s optimistic outlook and a value system centered around positivity and hope. The study recognized the influence of cultural contexts on music preferences and moral values, emphasizing that interpretations could vary across societies. However, these findings extend beyond mere correlation, suggesting that music serves as a mirror reflecting our ethical compass. The implications are far-reaching, with potential applications ranging from personalized music suggestions to music therapy in mental health settings. Understanding this intricate connection may even open avenues for music-based interventions that could foster positive moral development in society.

8000 steps a day keep the doctor away

Stens NA et al. Relationship of Daily Step Counts to All-Cause Mortality and Cardiovascular Events. Journal of the American College of Cardiology, October 2023.

A recent study has not only determined the optimal number of daily steps to maximize health benefits but has also underscored the advantages of brisk walking. The data showed that for a reduced risk of cardiovascular disease and premature death, around 8,000 steps per day is the target. These 8,000 steps are roughly 6.4 kilometers daily, considering the average human stride length (76 centimeters for men and 67 centimeters for women). The study emphasizes the superiority of brisk walking over a slower pace, particularly in reducing the risk of cardiovascular mortality, where the most significant benefits occur around 7,000 steps.  This comprehensive study, based on a systematic review of 12 international studies encompassing over 110,000 participants, finds no discernible gender differences. It also highlights that faster walking is associated with a decreased mortality risk, regardless of the total daily step count. Notably, the method used for tracking steps (smartwatch, wrist-based activity tracker, or smartphone) does not impact the recommended step targets. Researchers insist that increasing the number of steps is never harmful. Even walking as many as 16,000 steps a day can bring additional benefits, although the differences in risk reduction are marginal. The ideal step count should be age-appropriate, with younger individuals setting higher targets compared to older individuals. Ultimately, the study aims to provide clear and easily measurable daily step goals, complementing international physical activity recommendations, which recommend 150-300 minutes of moderate-intensity exercise per week. The convenience of step counting, facilitated by the widespread use of smartphones and smartwatches, makes this approach more accessible for many.  This study shows that even modest increases in daily steps can yield substantial health benefits, encouraging those with low levels of physical activity to set modest, achievable, and incremental goals.

Rats may have an imagination too

Lai et al. Volitional activation of remote place representations with a hippocampal brain–machine interface. Science, November 2023.

Humans and animals seem to share the ability to imagine and think beyond their immediate surroundings. In a recent scientific revelation, researchers have discovered that rats, similar to humans, possess the ability to imagine places and objects not physically present. Leveraging a unique combination of virtual reality technology and a brain-machine interface (BMI), scientists have found that rats can generate neural activity patterns associated with specific locations and objects, even in the absence of their physical presence. This ability to imagine distant locations is crucial for the recollection of past events and the conceptualization of potential future scenarios, indicating that animals, like humans, have a form of imagination. The researchers developed a real-time “thought detector” through the BMI, establishing a direct correlation between neural activity and a comprehensive 360-degree VR arena. This framework enabled researchers  to effectively measure and decode cognitive processes taking place in the rat’s brain.. Beyond highlighting the mental sophistication of animals, this research has the potential to catalyze advancements in the rapidly evolving field of Neuroprosthesis. Neuroprosthesis encompasses the utilization of brain functions to operate and control various technological devices such as artificial limbs, robotic arms, or hearing implants. This study opens up new avenues for exploring the intricacies of animal cognition and its potential implications for the development of cutting-edge neuroscientific technologies.

The remains of an ancient planet Theia lie deep within Earth

Yuan et al. Moon-forming impactor as a source of Earth’s basal mantle anomalies. Nature. November, 2023

In the 1980s, geophysicists made a remarkable discovery deep within the Earth: two colossal, continent-sized structures of mysterious material nestled beneath the African continent and the Pacific Ocean. Known as Large Low-Velocity Provinces (LLVPs), these massive anomalies, each approximately twice the size of the Moon, exhibit elemental compositions distinct from the surrounding mantle. A recent study has put forward a captivating hypothesis, proposing an origin for these perplexing formations. Researchers suggest that the LLVPs are remnants of an ancient planet that violently collided with Earth billions of years ago, coinciding with the monumental impact that birthed the Moon. This study also offers a solution to another long-standing planetary science mystery. While the formation of the Moon following a colossal collision between Earth and a smaller planet named Theia has been widely theorized, no evidence of Theia’s existence has ever been discovered in the asteroid belt or meteorites. The new study postulates that a substantial portion of Theia was absorbed into a young Earth, forming the LLVPs, while the remaining debris from the collision coalesced to form the Moon. Simulations suggest that the impact could have led to the formation of both the LLVPs and the Moon. The upper mantle absorbed much of the impact’s energy, resulting in Earth’s lower mantle being cooler than previously estimated. Consequently, the iron-rich material from Theia endured and settled near the base of the mantle. This finding has implications for understanding Earth’s early formation, including processes like plate tectonics. It suggests that the LLVPs have an ancient origin and may have influenced the planet’s early development, such as the onset of subduction and the formation of the first continents.

Human activity is taking Earth to the brink

Richardson K. et al. Earth beyond six of nine planetary boundaries. Science Advances, September 2023.

A new study suggests that Earth has been increasingly becoming uninhabitable for humans. Human activities are on the verge of significant, irrevocable transformations within our planet’s environment. This study reveals that, due to human-induced pollution and the degradation of natural ecosystems, six of the nine established planetary boundaries have already been transgressed. These boundaries, established by scientists in 2009, “all represent components of Earth system critically affected by anthropogenic (i.e., generated by humans) activities and relevant to Earth’s overall state.”

1- Integrity of biosphere

2- Climate change

3- Changes in freshwater supplies and availability

4- Changes in land system

5- The accumulation of novel chemical entities such as synthetic chemicals and nuclear waste

6- Biogeochemical flows such as the global nitrogen cycle

7- Acidification of oceans

8- Ozone depletion in stratosphere

9- Aerosol loading in atmosphere

An extensive analysis, drawing upon a compilation of 2,000 previous studies confirmed that six boundaries (1 through 6 above) have unfortunately been transgressed. Consequently, our planet now finds itself in a condition that surpasses the defined “safe operating space for humanity.” These findings imply that Earth’s life support systems, which have been relatively stable from the last ice age 10,000 years ago until the start of the Industrial Revolution, are now being pushed to extreme directions. While these results are obviously alarming, there is still hope. Since Earth is a dynamic, living entity, the exact ramifications are impossible to predict. However, computer simulations suggest that we can potentially halt this trajectory by concentrating efforts on saving forests, thereby overcoming the issue of climate change. Reverting to the forest levels of the late 20^th century is predicted to divert substantial excess carbon dioxide in the air, mitigating global temperature rise and enhancing biodiversity, offering a promising path forward.

Brain circuits underlying obesity

Barbosa DAN et al. An orexigenic subnetwork within the human hippocampus. Nature, August 2023.

A recent study has illuminated a crucial connection between memory and appetite within the human brain, shedding light on the underlying factors contributing to obesity. To delve into this phenomenon, researchers conducted brain scans on a cohort comprised of 34 subjects spanning a spectrum of body types, ranging from lean to overweight to obese. During these brain scans, participants were presented with a sweet indulgence in the form of a chocolate milkshake, which they subsequently consumed. This experimental setup allowed the researchers to closely monitor real-time neural responses associated with anticipation and reward.

The imaging sessions revealed a noteworthy observation: individuals classified as obese exhibited impaired connections between the dorsolateral hippocampus (dlHPC), situated in the brain’s memory processing domain, and the lateral hypothalamus (LH), responsible for regulating physiological equilibrium. This suggests a disruption in the regulation of emotional responses when anticipating pleasurable treats. Notably, both the dIHPC and the LH play pivotal roles within this circuit.

Furthermore, a direct correlation emerged in individuals with obesity between the extent of dysfunction within the hypothalamus-hippocampus circuit and their Body Mass Index (BMI). Higher BMI values were associated with more pronounced disruptions. These discoveries emphasize that certain individuals may possess fundamental differences in brain regions that heighten the risk of obesity. Consequently, addressing obesity and related eating disorders should extend beyond the conventional approach of self-control and dietary choices. Rather, future therapeutic interventions should explore innovative strategies that include restoring dysfunctional brain circuits and acknowledging the intricate interplay between memory and appetite as a promising avenue for intervention.

AI tool identifies eye diseases and predicts systematic health

Zhou Y et al. A foundation model for generalizable disease detection from retinal images. Nature, September 2023.

A novel artificial intelligence (AI) tool called RETFound has been developed by researchers to harness retinal images for the diagnosis and prediction of various health conditions, including ocular diseases, heart failure, and Parkinson’s disease. RETFound distinguishes itself by utilizing self-supervised learning to eliminate the need for manual labeling of retinal images during training, which is typically time-consuming and costly. Retinal images offer a unique window into an individual’s overall health, affording a direct view of the body’s capillary network, thereby revealing signs of cardiovascular disease and neural tissue health. AI aids in interpreting these scans, making them accessible to more individuals. Following an initial phase of pre-training on an extensive dataset of unlabeled retinal images, RETFound exhibited rapid adaptability to recognize specific disease-related retinal features when introduced to a small number of labeled images for various health conditions. RETFound demonstrated notable proficiency in detecting ocular diseases such as diabetic retinopathy and showed promise in predicting the risk of systemic diseases, though further improvement is still needed. The model represents a noteworthy application of foundational AI models within the realm of medical imaging, and researchers are actively exploring its potential application to other categories of medical imaging beyond retinal scans.

Air pollution may underlie the global decline in insect numbers

Wang et al. Short-term particulate matter contamination severely compromises insect antennal olfactory perception. Nature Communications, July 2023.

Communication plays a critical role in the lives of animals, as the loss of communication sways their ability to find food and locate mates to reproduce. Odors are the main source of communication for insects, which use their receptors on the antennae to detect odor molecules to find the location of a potential food or mate. New research shows that particulate air pollution has a detrimental impact on insects. Particulate matter, which is typically released from the combustion of fossil fuels, includes toxic heavy metals and organic substances. While the large particles (>10 micron) can irritate eyes and nose, smaller particles (<2.5 micron) can travel deep into the human lungs as well as accumulate on the antennae of insects shown in this study. The researchers studied the houseflies collected from urban Beijing and rural Australian areas and found that surprisingly both populations had smaller particulate matters accumulated on the antennae of diverse insects, including bees, wasps, moths, and flies. Electron microscopy analyses revealed that these insect antennae contained hazardous materials such as silicate, sulfurate, fly ash and metal particles. The researchers utilized some neural behavior tests and found that exposure to air pollution, even for 12 hours, significantly reduced the strength of odor-related electrical signals in the fly brains and compromised their sense of smell. These results suggest that when insect antennae become clogged with pollution particles, insects will struggle to smell food, a mate, or a place to lay their eggs, and it follows that their populations will decline. Remarkably, insects from remote and comparatively rural habitats have also similar contaminants showing how the particulate material can be carried thousands of kilometers, likely by air currents. Insects play fundamental roles in our ecosystem through the regulation of pests and diseases, pollination, and nutrient cycling. Air pollution is likely to be one key driver of global declines in insect populations, alarmingly calling for new global pollution regulations.

New evidence for an alien life in Mars?

Sharma et al. Diverse organic-mineral associations in Jezero crater, Mars. Nature, July 2023.

All known life in our planet is based on organic compounds, primarily composed of carbon and hydrogen. They’re also present widespread in the universe including Mars and it has been

a big controversy whether the existence of organic compounds can be a signature of life alone. A recent data from Nasa’s Perseverance rover has shed important insights into this question. Since 2021, Perseverance has been investigating the Mars’ Jezero Crater, a giant 28-mile-wide crater, which is thought to be a basin that once housed an ancient lake. Scientists believe that the Jezero crater was created from a meteorite’s impact around 3-4 billion years ago and the conditions in this lake basin may have been favorable to life. The recent evidence was collected using an instrument called SHERLOC, which is mounted on the robotic arm of the six-wheeled rover that enables to carry out the analysis of organic molecules and detailed mapping. Interestingly, the rover detected signatures in the crater floor rocks with a range of diverse organic molecules containing one or two rings of carbon. These classes of organic molecules seemed to occur with different spatial patterns within these compositionally distinct formations, potentially indicating a change in their levels over time. This suggests that there were either several distinct ways of synthesizing these organic compounds or that they were deposited and preserved by water, or in combination with volcanic materials. While scientists are excited about the great volume and diversity in the rocks collected, they are cautious to call this as a sign of alien life. There are both biotic and abiotic mechanisms that can form organic molecules. Infall from meteorites or water-rock interactions can also produce these organics abiotically. On the other hand, it is equally possible that an ancient life could produce these organics as well.  Researchers can’t wait to look at these rocks in earthbound labs to draw more definitive conclusions. Mars Sample Return (MSR) mission is expected to launch from Earth around the late 2020s, but the trip should be obviously worth the wait.

AI-powered robots as a potential remedy for loneliness epidemic

Broadbent et al. Enhancing social connectedness with companion robots using AI. Science Robotics, July 2023.

A recent study suggests that in the era of growing social isolation, companion robots enhanced with artificial intelligence (AI) may one day help alleviate the loneliness epidemic. Loneliness is estimated to affect about one-third of the global population, leading to serious health issues including obesity, dementia, and even early death. Researchers in this study first map some of the ethical considerations for governments, policy makers, tech developers and clinicians, and urges all stakeholders to come together to rapidly develop viable and reliable guidelines for trust, agency, engagement, and real-world efficacy. Second, they developed a patient-rated outcome measure called the “Companion Robot Impact Scale (Co-Bot-I-7)” which aims to establish the impact on physical health and loneliness. Their preliminary results showed that amiable androids help reduce stress and even promote skin healing after a minor wound. The team also highlights that doctors agree with this idea. Among 307 care providers across Europe and US, 69 percent of physicians approved of robots providing companionship to relieve isolation and potentially improve a patients’ mental health. Commercially available companion robots like ElliQ have already demonstrated their ability to reduce stress and loneliness while helping older individuals maintain an active and healthier lifestyles. The team foresees that the newer generations of robots, embedded with more advanced AI programs such as ChatGPT and other generative AI models, hold the potential to establish even stronger social connections with humans by engaging in spontaneous conversations and even mimicking the voices of deceased loved ones. It is believed that with the appropriate ethical guidelines, there is potential to utilize robots in establishing a healthier society. While these robots are not intended to replace genuine human companionship, they serve as valuable tools to enhance well-being and support individuals experiencing loneliness, especially in the elderly demographic.

Forever young: boosting cell longevity with synthetic biology tools

Zhou et al. Engineering longevity-design of a synthetic gene oscillator to slow cellular aging. April 2023, Science.

Scientists discovered a new way to reprogram the cellular aging process using synthetic biology. A recent study showed that the lifespan of yeast cells can be increased by 82% by utilizing a biosynthetic clock to rewire the circuit controlling normal deterioration. Yeasts are single-celled microorganisms that have been used as a model for the aging of human cells. The team used microfluidics and time-lapse microscopy to track the aging processes across the yeast’s lifespan.

Scientists genetically rewired the yeast circuit that controls cell aging by engineering a negative feedback loop. This in turn resulted in a clock-like device, also named as “gene oscillator,” which drove the cell to periodically switch between two detrimental “aged” states, avoiding prolonged commitment to either and thus slowing degeneration. These molecular tweaks resulted in a dramatically extended cellular lifespan, setting a record for life extension through genetic and chemical manipulations. This study represents a proof-of-concept for a synthetic biology approach to reprogram the cellular aging process and lays the foundation for designing synthetic gene circuits to effectively promote longevity in humans. The team is currently focusing their research on the aging of diverse human cell types, including stem cells and neurons.

Humidity may raise global heat stress

Zhang K et al. Increased heat risk in wet climate induced by urban humid heat. April 2023, Nature.

As temperatures worldwide continue to rise, urban areas are facing increased heat stress and risks. 55% of the global population, 4.3 billion people, live in urban settings, and, unfortunately, many people in urban settlements do not have viable ways to mitigate extreme heat. It is estimated that by 2050, 80% of the world’s population will live in urban settings and be at risk of increased impact from heat. While cities tend to be warmer and drier than rural lands, in the global south, including Latin America, Africa, Asia and Oceania, humidity causes another complicating factor. Using observational data and climate model calculations, researchers found that that heat stress is highly dependent on local climate, and, surprisingly, humidity can also reverse the cooling effect that would come from trees and other vegetation. Green vegetation can lower air temperatures via water evaporation in some conditions, but it can also increase the heat burden in a local microenvironment because of air humidity. The study found that in wetter climates, the summer wet bulb temperatures in urban areas are 0.17 °C higher than in rural regions.

While this variation may look very small, it is enough to cause 2 to 6 extra dangerous heat-stress days per summer for urban residents in these climate conditions. With the projected increase in global temperatures, humidity may amplify the heat risks in cities of the global south. These findings had triggered further research to explore novel approaches to mitigate heat stress and combat a warming climate. Preliminary diagnostic analyses suggest that enhancing urban convection efficiency (the efficiency of dissipating heat and water) and reducing heat storage at night may reduce daytime and nighttime urban humid heat, respectively.

Fascinating feathers of an African bird

Mueller J. Structure and mechanics of water-holding feathers of Namaqua sandgrouse. April 2023, Journal of the Royal Society Interface.

Birds’ feathers are known to have an extraordinary ability to repel water. One particular pigeon-size bird, the Namaqua sandgrouse, has belly feathers that are incredibly efficient at absorbing and retaining water. A sandgrouse can fly over 20 kilometers from a remote watering hole back to their nests in the extreme temperatures of Africa. In a recent study, scientists shed light on how sandgrouse feathers have unique water-carrying abilities. Using high-resolution microscopes, 3D technology and a vast collection of sandgrouse belly feathers, they found that unlike typical bird feathers, which have a central shaft with smaller barbs and barbules extending from it, sandgrouse feathers have two distinct zones. In the inner zone, the barbules have a helically coiled structure close to their base, followed by a straight extension. In the outer zone of the feather, the barbules are straight and do not have the helical coil. The barbules in both zones form protective tent-like structures, and tiny tubular structures in each barbule facilitate capturing water. From an engineering perspective, Sandgrouse feathers offer exceptional bio-inspired designs. Future applications could include netting systems that collect and retain water harvested from dew or fog in areas affected by drought, such as in desert regions. Moreover, the water intake mechanisms of the feathers might influence future engineering designs that require controlled absorption, secure retention, and the easy release of liquids.

Mary Evelyn Tucker and John Polkinghorne are our guests in Matter & Beyond this issue. Professor Tucker from Yale University correlates the spiritual crisis we face in modern times with the ecological crisis on the Earth. Tucker says we are obsessed with economic growth and this preoccupation is creating a number of different types of alienation, sadness, even addictions, because the emptiness of modern consumer life is suffocating the human soul. Polkinghorne, a Fellow of the Royal Society and the former President of Queens’ College, Cambridge, says that science does not tell us the whole story. For him science “needs supplementation by other forms of insight.” Further, he emphasizes how valuable we humans are when he says, “Obviously on the scale of the universe, we are very tiny creatures, and we inhabit a planet that is just a speck of dust, really in the great universe, but we are greater than all the stars because we know them and ourselves, and they know nothing.”

Each day new innovations in science and technology are introduced into our lives. It is often debatable whether scientific research is conducted for the sake of science to fulfill a human need, or if it is manipulated in a way to boost a consumerist economy by shoveling new products onto the market every day. Still, there are interesting findings and discoveries we can learn from the mass media and journals, which will inspire us each time with an appreciation of the glorious harmony found in the universe. Aiming to be a source of inspiration for those readers who seek knowledge through perceiving this harmony, The Fountain is launching Science Square, a new section which will feature a brief account of some of the most interesting scientific news, compiled from recently released papers and reviews. Proceed to the department and see how running barefoot is less damaging than running with shoes, see how pure water can remain liquid at temperatures down to –40 C, how cancer-causing DNA mutations are deciphered, and how scientists are inspired by the spider web.

The appeal of the Golden Ratio to the human eye and brain has been scientifically tested. When subjects are presented with a range of rectangles, people invariably pick out as most pleasing ones those whose sides are of the Golden Ratio. This golden number is the basic number at work in aesthetics; there are even claims that the Golden Ratio was used by Leonardo da Vinci when painting the Mona Lisa, and by the Greeks in building the Parthenon. But the surprising thing is that a number deemed aesthetically pleasing by human beings also crops up in nature and science. In a newly published article in Physical Review B, it is stated that the Golden Ratio appears in the structures of some metals. The Golden Ratio is seen in the arrangement of seeds on flower heads, in the spirals of sea shells and galaxies, even in black holes. This ratio can be found almost everywhere in the universe.

Although the Greek mathematician Euclid first defined the Golden Ratio in around 300 BC, the followers of Pythagoras probably knew of it two centuries earlier. Euclid defined it as a line that can be divided into two unequal parts (Figure 1), where the ratio of the smaller part of the line to the longer part is the same as the ratio of the longer part to the whole. This ratio is 1.6180339887…, the Golden Number.

What makes the Golden Ratio special is the number of mathematical properties it possesses. The Golden Ratio is the only number whose square can be produced simply by adding 1 and the reciprocal of which can be arrived at by subtracting 1. If you take a Golden Rectangle – that is a rectangle where the length-to-breadth ratio is equal to the Golden Ratio, and take out a square, what remains is another, smaller Golden Rectangle. Also, think of any two numbers. Make a third by adding the first and second, a fourth by adding the second and third, and so on. If you start with 7 and 11, then what you have is:

7, 11, 18, 29, 47, 76… When you have written down approximately 20 numbers, calculate the ratio of the last to the penultimate: the answer should approximate the Golden Number.

In mathematical terminology it is (an/an-1) equals to the Golden Ratio.

Another example of the Golden Ratio is the Fibonacci Numbers, that is a number series where each number is simply the sum of the previous two numbers. These numbers are 1, 1, 2, 3, 5, 8, 13, 21, 34, 55… The ratio between any two successive Fibonacci numbers approaches the Golden Ratio as the numbers get larger. We can find the Fibonacci series particularly in the spirals of sea shells and in the arrangement of seeds on sunflower heads.

It was the elusive nature of the Golden Ratio that led the Italian friar and mathematician Luca Pacioli to equate it with the incomprehensibility of God. In the 15th century, he wrote a three-volume treatise, Divina Proportione (Divine Proportion), that was crucial in the dissemination of the Golden Ratio beyond the world of mathematics. After him, many artists, architects, and musicians used the Golden Ratio in their works; for example, musicians such as Debussy and Bartok and the architect Le Corbusier.

Let’s examine the arrangement of leaves on the stem of the plant Phyllotaxis. As each new leaf grows, it does so at an angle offset from the leaf below. The most common angle between successive leaves is 137.5 degrees – the Golden Angle; 137.5=3d 360-360/G, where G is the Golden Ratio. Why does the Golden Ratio play a role in the arrangement of leaves? It is all down to the irrationality of the number. A new leaf must collect sunlight without throwing too much of a shadow on the leaves below. A plant must arrange its leaves in such a way that the greatest number can spiral around the stem before a new leaf can sprout immediately above a lower one – that is at 360 degrees. If the leaves were arranged at an angle of 120 degrees, then the leaves would grow as 3 separate columns with large gaps between them. This would effectively block out the sunlight to the lower leaves. If the angle were 50 degrees, then there would be spaces between the leaves. But, with an angle of 137.5, the maximum amount of leaves can be arranged with a minimum of space being left between the leaves.

The Golden Ratio also crops up in hard sciences. Let’s take a look at the growth of “quasi-crystals.” These maintain a five-fold symmetry, which means that they make a pattern that looks the same when rotated by multiples of one-fifth of 360 degrees. Since the time when these crystals were discovered in 1984, many physicists have been researching their properties. In Brookhaven National Lab in New York State, Tanhong Cai imaged the microscopic terrain of the surface of such crystals made from alloys of aluminum-copper-iron and aluminum-palladium-manganese. It is found that flat terraces are punctuated by abrupt vertical steps. The steps come in two predominant sizes, with the ratio of the heights of these two steps being the Golden Ratio. This fact was discovered in 2002.

The most surprising place where the Golden Ratio appears is in black holes, a discovery made by Paul Davies of the University of Adelaide in 1989. Black holes and other self-gravitating bodies, such as the sun, have a negative specific heat. This means that they get hotter as they lose heat. In a spinning black hole there is an outward centrifugal force acting to prevent any shrinkage of the hole. The force depends on how fast the black hole is spinning. It turns out that at a critical value of the spin (when the ratio between the square root of the mass value and the square root of the spinning parameter is equal to the golden ratio), a black hole flips from having negative to positive specific heat. In other words, the Golden Ratio determines the character of the black hole.

Figure 2 shows the finger bones of a hand. The ratio of each bone at the top of the hand to the bones at the bottom of the fingers is the Golden Ratio. Pine-cones show the Golden Ratio spiral clearly (Figure 3). If one looks carefully at an ordinary cauliflower, one can see a center point where the florets are smallest, and the florets are organized in spirals around this center in both directions (Figure 4). The flower, Echinacea Purpura, has the same spirals (Figure 5).

With the help of developing science, new examples of the Golden Ratio are waiting to be discovered in the universe. The latest discoveries demonstrate that by using this ratio in technology, new products which make our lives easier will soon be available to all. This mystery that is spread throughout the universe may be an opportunity to renew and change our points of view on life.

Reference

• Chown, Marcus, “Why Should Nature Have a Favorite Number,” New Scientist, 21-28 December 2002, 55-56.