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Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:21am

Why your best friends' genes matter

"Choose your friends wisely, no scientifically". Because ....

A study by researchers shows that your best friend's traits can rub off on you—especially ones that are in their genes.

The genetic makeup of adolescent peers may have long-term consequences for individual risk of drug and alcohol use disorders, depression and anxiety, the groundbreaking study has found.

Peers' genetic predispositions for psychiatric and substance-use disorders are associated with an individual's own risk of developing the same disorders in young adulthood.

The data of this study exemplifies the long reach of social genetic effects.

Socio-genomics—the influence of one person's genotype on the observable traits of another—is an emerging field of genomics. Research suggests that peers' genetic makeup may influence health outcomes of their friends.

In the studies conducted, even when controlling for factors such as the target individuals' own genetic predispositions and family socioeconomic factors, the researchers found a clear association between peers' genetic predispositions and target individuals' likelihood of developing a substance use or psychiatric disorder. The effects were stronger among school-based peers than geographically defined peers.

Within school groups, the strongest effects were among upper secondary school classmates, particularly those in the same vocational or college-preparatory track between ages 16 and 19. Social genetic effects for school-based peers were greater for drug and alcohol use disorders than major depression and anxiety disorder.

More research is needed to understand why these connections exist. 

The most obvious explanation for why peers' genetic predispositions might be associated with our own well-being is the idea that our peers' genetic predispositions influence their phenotype, or the likelihood that peers are also affected by the disorder.

This research also underscores the importance of disrupting processes and risks that extend for at least a decade after attendance in school. Peer genetic influences have a very long reach.

Peer Social Genetic Effects and the Etiology of Substance Use Disorders, Major Depression, and Anxiety Disorder in a Swedish National Sample, American Journal of Psychiatry (2024). DOI: 10.1176/appi.ajp.20230358

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:09am

It's common knowledge that flying is not good for the climate. However, most people do not appreciate that contrails and jet fuel carbon emissions cause a double-whammy warming of the climate.
This study throws a spanner in the works for the aviation industry. Newer aircraft are flying higher and higher in the atmosphere to increase fuel efficiency and reduce carbon emissions. The unintended consequence of this is that these aircraft flying over the North Atlantic are now creating more, longer-lived, contrails, trapping additional heat in the atmosphere and increasing the climate impact of aviation.
This finding reflects the challenges the aviation industry faces when reducing its climate impact.
The study did confirm a simple step that can be taken to shorten the lifetime of contrails: Reduce the amount of soot emitted from aircraft engines, produced when fuel burns inefficiently.

Modern aircraft engines are designed to be cleaner and typically emit fewer soot particles, which cuts down the lifetime of contrails.

While other studies using models have predicted this phenomenon, the study published today is the first to confirm it using real-world observations.
Even higher in the sky, the researchers found that private jets create contrails more often than previously thought—adding to concerns about the excessive use of these aircraft by the super-rich.

Despite being smaller and using less fuel, private jets create similar contrails to much larger commercial aircraft, the analysis found.
Private jets fly higher than other planes, more than 40,000 feet above earth where there is less air traffic. However, like modern commercial aircraft creating more contrails compared to lower-flying older commercial aircraft, the high altitudes flown by private jets means they create outsized contrails.

 Operational differences lead to longer lifetimes of satellite detectable contrails from more fuel efficient aircraft, Environmental Research Letters (2024). DOI: 10.1088/1748-9326/ad5b78

Part 2

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 9:04am

Modern aircraft emit less carbon than older aircraft, but their contrails may do more environmental harm

Modern commercial aircraft flying at high altitudes create longer-lived planet-warming contrails than older aircraft, a new study has found.

The result means that although modern planes emit less carbon than older aircraft, they may be contributing more to climate change through contrails.

The study highlights the immense challenges the aviation industry faces to reduce its impact on the climate. The new study also found that private jets produce more contrails than previously thought, potentially leading to outsized impacts on climate warming.

Contrails, or condensation trails, are thin streaks of cloud created by aircraft exhaust fumes that contribute to global warming by trapping heat in the atmosphere.

While the exact warming effect of contrails is uncertain, scientists think it is greater than warming caused by carbon emissions from jet fuel.
Published in Environmental Research Letters, the study used machine learning to analyze satellite data on more than 64,000 contrails from a range of aircraft flying over the North Atlantic Ocean.

Modern aircraft that fly at above 38,000 feet (about 12km), such as the Airbus A350 and Boeing 787 Airliners, create more contrails than older passenger-carrying commercial aircraft, the study found.

To reduce jet fuel consumption, modern aircraft are designed to fly at higher altitudes where the air is thinner with less aerodynamic drag, compared to older commercial aircraft, which usually fly at slightly lower altitudes (around 35,000ft/11km).

This means these higher-flying aircraft create less carbon emissions per passenger. However, it also means they create contrails that take longer to dissipate—creating a warming effect for longer and a complicated trade-off for the aviation industry.

Part 1

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 8:47am

The raccoon dog's significantly smaller brain size supports this hypothesis, highlighting that factors other than domestication, such as ecological adaptations like hibernation, can also drive reductions in brain size.

The study concludes that while domestication does contribute to brain size reduction in dogs, it should not be overemphasized as a uniquely powerful evolutionary force.

The findings suggest that other ecological and evolutionary pressures can similarly affect brain size and can mediate extreme variations in non-domesticated species as well. A more balanced and less human-focused perspective could refine our understanding of the complex interplay between domestication and brain size evolution in mammals.

 László Zsolt Garamszegi et al, The reduction in relative brain size in the domesticated dog is not an evolutionary singularity among the canids, Biology Letters (2024). DOI: 10.1098/rsbl.2024.0336 , royalsocietypublishing.org/doi … .1098/rsbl.2024.0336

Part 2

Comment by Dr. Krishna Kumari Challa on August 8, 2024 at 8:46am

Domestication causes smaller brain size in dogs than in the wolf: Study challenges notion

A recent study, published in Biology Letters, challenges the long-held notion that domestication is the primary driver of reduced brain size in domesticated animals, specifically dogs.

Employing a phylogenetic comparative approach, researchers  show that the domesticated dog does not exhibit an exceptionally small brain relative to its body size compared to other canid species, suggesting that  domestication is not as unique an evolutionary force as previously thought.

The prevailing belief has been that domestication leads to a significant reduction in brain size due to relaxed selection pressures, such as reduced need for foraging, mating competition, and predator avoidance.

This phenomenon is thought to be a result of the decreased necessity for metabolically costly brain tissue in a domesticated environment. While domesticated dogs show a substantial decrease in brain size compared to their wild ancestor, the gray wolf (Canis lupus), this study aimed to determine if this reduction is exceptional when viewed in a broader phylogenetic context.

Researchers analyzed brain and body size data for 25 canid species, including ancient dog breeds that are genetically closer to the ancestral domesticated dog.

Their phylogenetic predictions and allometric regressions showed that the reduction in brain size in domesticated dogs is not an unambiguous evolutionary singularity. The observed brain size in dogs fell within the expected range for most ancient breeds used in the study, suggesting that domestication is not uniquely influential in reducing brain size among canids.

Interestingly, the study found that the common raccoon dog (Nyctereutes procyonoides), which hibernates, is a more pronounced outlier in terms of brain size reduction. Hibernation, associated with prolonged periods of low metabolic activity and food scarcity, is hypothesized to constrain brain size evolution due to the high energy demands of large brains.

Part 1

Comment by Dr. Krishna Kumari Challa on August 7, 2024 at 10:54am

What Your Nails Say About Your Health

https://youtu.be/PRftXdvENRw?si=VgUs4ne4n_eT2KL_

Comment by Dr. Krishna Kumari Challa on August 7, 2024 at 9:29am

Looking inside a microchip with 4 nanometer precision: New X-ray world record

Researchers  have used X-rays to look inside a microchip with higher precision than ever before. The image resolution of 4 nanometers marks a new world record. The high-resolution three-dimensional images of the type they produced will enable advances in both information technology and the life sciences.

The researchers  reported their findings in the current issue of the journal Nature.

Since 2010, the scientists have been developing microscopy methods with the goal of producing three-dimensional images in the nanometer range. In their current research, they have succeeded for the first time in taking pictures of state-of-the-art computer chips microchips with a resolution of 4 nanometers—a world record.

Instead of using lenses, with which images in this range are not currently possible, the scientists resort to a technique known as ptychography, in which a computer combines many individual images to create a single, high-resolution picture. Shorter exposure times and an optimized algorithm were key to significantly improving upon the world record they themselves set in 2017. For their experiments, the researchers used X-rays from the Swiss Light Source SLS at PSI.

Tomas Aidukas et al, High-performance 4-nm-resolution X-ray tomography using burst ptychography, Nature (2024). DOI: 10.1038/s41586-024-07615-6

Comment by Dr. Krishna Kumari Challa on August 7, 2024 at 9:03am

This could involve examining patients who have a restricted orexin system for genetic reasons—this is the case in around one in two thousand people. These people suffer from narcolepsy (a sleeping disorder). Another possibility would be to observe people who receive a drug that blocks orexin. Such drugs are authorized for patients with insomnia.

If we understand how the brain arbitrates between food consumption and physical activity, we can develop more effective strategies for addressing the global obesity epidemic and related metabolic disorders.
Interventions could be developed to help overcome exercise barriers in healthy individuals and those whose physical activity is limited.

Orexin neurons mediate temptation-resistant voluntary exercise, Nature Neuroscience (2024). DOI: 10.1038/s41593-024-01696-2

Comment by Dr. Krishna Kumari Challa on August 7, 2024 at 9:01am

 How our brain decides what to do

 What exactly happens in our brain when we make a decision has been a mystery till now. But researchers  have found the solution. They have deciphered which brain chemical and which nerve cells mediate this decision: the messenger substance orexin and the neurons that produce it.

These neuroscientific fundamentals are relevant because many people don't take good decisions like getting enough exercise because they don't find it easy to decide. Most of us have probably already decided once or even several times to skip exercising in favor of one of the numerous alternative temptations of daily life. According to the World Health Organization, 80% of adolescents and 27% of adults don't get enough exercise. And obesity is increasing at an alarming rate not only among adults but also among children and adolescents.

Despite these statistics, many people manage to resist the constantly present temptations and get enough exercise.

In their experiments with mice, the researchers were able to show that orexin plays a key role in taking decisions. It's one of over a hundred messenger substances that are active in the brain. Other chemical messengers, such as serotonin and dopamine, were discovered a long time ago and their role has largely been decoded. The situation for orexin is different: Researchers discovered it relatively late, around 25 years ago, and they are now clarifying its functions step by step.

In neuroscience, dopamine is a popular explanation till now  for why we choose to do some things but avoid others. This brain messenger is critical for our general motivation. However, our current knowledge about dopamine does not easily explain why we decide to exercise instead of eating. Our brain releases dopamine both when we eat and when we exercise, which does not explain why we choose one over the other.

To find out what does explain this, the researchers devised a sophisticated behavioral experiment for mice, which were able to choose freely from among eight different options in ten-minute trials. These included a wheel they could run on and a "milkshake bar" where they could enjoy a standard strawberry-flavored milkshake.

"Mice like a milkshake for the same reason people do: It contains lots of sugar and fat and tastes good.

In their experiment, the scientists compared different groups of mice: one made up of normal mice and one in which the mice's orexin systems were blocked, either with a drug or through genetic modification of their cells.

The mice with an intact orexin system spent twice as much time on the running wheel and half as much time at the milkshake bar as the mice whose orexin system had been blocked. Interestingly, however, the behavior of the two groups didn't differ in experiments in which the scientists only offered the mice either the running wheel or the milkshake.

This means that the primary role of the orexin system is not to control how much the mice move or how much they eat. Rather, it seems central to making the decision between one and the other, when both options are available. Without orexin, the decision was strongly in favor of the milkshake, and the mice gave up exercising in favour of eating.

researchers expect that orexin may also be responsible for this decision in humans; the brain functions involved here are known to be practically the same in both species.

The researchers are now trying to verify this  in humans too.

Part 1

Comment by Dr. Krishna Kumari Challa on August 7, 2024 at 8:50am

'Cool paint' for cars to keep drivers cooler

Car companies are trying  "cool paint" to keep people inside vehicles cooler, although the coating is six times thicker, making commercialization still a challenge.

The vehicles with the special paint looked like ordinary cars, but felt much cooler to the touch.

The cool paint lowered the cars' roof-panel temperature by 12 degrees Celsius (22 degrees Fahrenheit) and the interiors by 5 C (9 F).

Cooling materials are already widely used in buildings and other items. Cooler cars can reduce use of air-conditioning and relieve the toll from heat on engines and electric vehicle batteries.

They have  also been experimenting with paint that delivers lower cabin temperatures, mostly focusing on colours that refract the sun's rays.

The cool paint reflects sunlight better and also creates electromagnetic waves that block the rays, redirecting energy away from vehicles.

Source: Various news agencies

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