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Comment by Dr. Krishna Kumari Challa on November 5, 2024 at 9:11am

They found that cooling efficiency follows a power law across scales—from as small as 120 by 120 meters to as large as regions covering the entire city. The relationship holds across all four of the studied cities, which are in very different climates. This suggests that it could be used to predict the amount of additional tree cover needed to achieve specific heat mitigation and climate adaptation goals in cities worldwide.
While the paper provides essential information for decision-making at the municipal level, the researchers caution that urban planners may also need to work at smaller scales to ensure that urban trees—and their potential benefits—are distributed equitably across the city, and with community buy-in.

Jia Wang et al, A scaling law for predicting urban trees canopy cooling efficiency, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2401210121

Part 2

Comment by Dr. Krishna Kumari Challa on November 5, 2024 at 9:09am

How many trees does it take to cool a city? Researchers develop tool to set urban tree canopy goals

Cities around the globe are increasingly experiencing dangerous heat as urban concrete and asphalt amplify rising temperatures. Tree-planting programs are a popular, nature-based way to cool cities, but these initiatives have been largely based on guesswork and extrapolation. A study published recently in Proceedings of the National Academy of Sciences offers a new tool for urban planners and decision makers to set more specific and science-based city-wide greening goals.

Trees are good at cooling because they pump a lot of water from the ground into the air, and when that water evaporates at the leaf surface, it absorbs a vast amount of heat. That's just the physics of evaporation. The shade provided by trees also helps with cooling.

To date, most studies measuring the cooling effects of urban trees focus on the hyperlocal level, such as on a particular street or neighborhood. When the urban tree canopy expands by 1%, for example, nearby temperatures may decrease by 0.04 to 0.57 degrees Celsius.

But how much tree canopy do we actually need for the whole city?

Researchers set out to determine how trees' cooling efficiency—the temperature reduction associated with a 1% increase urban tree canopy—changes across larger areas.

The team analyzed satellite imagery and temperature data from four cities with very different climates: Beijing and Shenzhen in China, and Baltimore and Sacramento in the US. Baltimore and Beijing are temperate, Shenzhen is subtropical, and Sacramento is in a Mediterranean climate zone.

First, they divided each city into pixels approximately the size of a city block. For each pixel, they measured the land surface temperature and how much of the ground was covered by trees. Then they ran the same analyses across larger and larger sections of each city, spanning the neighborhood level, city level, and beyond. Finally, they calculated how the mathematical relationship between greenery and temperature—the cooling efficiency—changed at different scales.

Overall, the team discovered that the cooling efficiency of urban trees increased at larger scales. But it did so at a slower rate at larger unit sizes. In Beijing, for example, a 1% increase in canopy at the block level decreases temperature by about 0.06 degrees, whereas a 1% increase in canopy at the city level could decrease temperature by about 0.18 degrees.
The additional benefit at larger scales seems to come from being able to include large groups of trees, which have a larger cooling capacity.

With greater clarity about the relationships between area, tree canopy cover, and cooling effects, the paper makes it possible to predict cooling effects at the whole-city scale, offering a valuable tool for managers to set urban tree canopy goals to reduce extreme heat.

Part 1

Comment by Dr. Krishna Kumari Challa on November 5, 2024 at 9:02am

Rainwater samples reveals it's literally raining 'forever chemicals'

PFAS are in rainwater. And it is the latest evidence the synthetic "forever chemicals"—that have raised health concerns for people and wildlife—hitch a ride on the water cycle, using the complex system to circulate over greater distances.

For more than a year, FIU researchers collected and analyzed 42 rainwater samples across three different sites in Miami-Dade County. A total of 21 perfluoroalkyl and polyfluoroalkyl substances, or PFAS, were detected, including PFOS and PFOA (since phased out of production over cancer concerns), as well as the newer varieties used in manufacturing today.

While profiles of several PFAS matched back to local sources, others did not. According to the study, published in Atmospheric Pollution Research, this suggests Earth's atmosphere acts as a pathway to transport these chemicals far and wide—contributing to the worldwide pollution problem.

PFAS are practically everywhere. Now scientists are able to show the role air masses play in potentially bringing these pollutants to other places where they can impact surface water and groundwater.

Widely used in consumer products—non-stick cookware, clothing, cosmetics, food packaging, detergents and firefighting foams, to name a few—PFAS were purposefully created to be almost indestructible. They don't break down easily or simply go away.

Once in the environment, they accumulate over time. People can ingest or inhale them, and exposure has been linked to liver and kidney damage, fertility issues, cancer and other diseases. The EPA warned even low levels of exposure can be dangerous, setting strict near-zero limits for some PFAS in drinking water.

It's still not very clear, though, how exactly these long-lived chemicals journey through the environment.

Scientists  have been trying to piece this picture together. They've detected PFAS in drinking water and surface water.

And, subsequently, also found PFAS in animals that live in those areas, including oysters and economically important recreational fish and lobsters. Rain was the natural next place they found it!

PFAS can infiltrate the atmosphere by either evaporation or getting absorbed into microscopic particles and dust. Wind and shifting air currents shuttle them along. Eventually, it rains. As each drop falls to earth, it brings along some of the pollutants. The cycle begins and ends and begins again.

This played out in the team's data.

Maria Guerra de Navarro et al, It's raining PFAS in South Florida: Occurrence of per- and polyfluoroalkyl substances (PFAS) in wet atmospheric deposition from Miami-Dade, South Florida, Atmospheric Pollution Research (2024). DOI: 10.1016/j.apr.2024.102302

Comment by Dr. Krishna Kumari Challa on November 5, 2024 at 8:08am

Insulin resistance caused by sympathetic nervous system over-activation, a paradigm-shifting study finds

Researchers  have found that overnutrition leads to insulin resistance and metabolic disorders through increased activity of the sympathetic nervous system (SNS). The study shows that reducing SNS activity can prevent insulin resistance induced by a high-fat diet, suggesting a new understanding of how obesity causes insulin resistance.

Obesity causes type 2 diabetes and metabolic diseases primarily by inducing insulin resistance. Impaired cellular insulin signaling is the most understood mechanism, but it does not always accompany impaired insulin action, indicating other factors must be involved.

The role of the SNS in obesity is complex and somewhat controversial. Previous studies have reported both increased and decreased SNS activity in obese people.

Overnutrition has been known to rapidly increase plasma norepinephrine (NE) levels, indicating overactivation of the SNS. Methods that directly measure SNS activity, such as nerve recordings and NE turnover, often report increased SNS activity in obesity.

In contrast, studies focusing on adrenergic signaling pathways sometimes report reduced catecholamine responses, interpreted as decreased SNS activity.

This discrepancy may be explained by the development of catecholamine resistance due to chronic sympathetic overactivation, leading to diminished physiological responses despite elevated NE levels.

In a study titled "Overnutrition causes insulin resistance and metabolic disorder through increased sympathetic nervous system activity," published in Cell Metabolism, the researchers investigated the conflicting reports on SNS activity in obesity.

 Kenichi Sakamoto et al, Overnutrition causes insulin resistance and metabolic disorder through increased sympathetic nervous system activity, Cell Metabolism (2024). DOI: 10.1016/j.cmet.2024.09.012

Comment by Dr. Krishna Kumari Challa on November 4, 2024 at 9:26am

Most of the research on the hormonal effect on the brain has been focused on brain communication during cognitive tasks, not the actual structures themselves.
Cyclic fluctuations in HPG-axis hormones exert powerful behavioral, structural, and functional effects through actions on the mammalian central nervous system.
The microstructure of white matter – the fatty network of neuronal fibers that transfer information between regions of gray matter – has been found to change with hormonal shifts, including puberty, oral contraception use, gender-affirming hormone therapy, and post-menopausal estrogen therapy.
To address the menstruation gap in our understanding, the team took MRI scans of their subjects during three menstrual phases: menses, ovulation, and mid-luteal. At the time of each of these scans, the researchers also measured the participants' hormone levels.

The results showed that, as hormones fluctuate, gray and white matter volumes change too, as does the volume of cerebrospinal fluid.

In particular, just before ovulation, when the hormones 17β-estradiol and luteinizing hormone rise, the brains of the participants showed white matter changes suggesting faster information transfer.

Follicle-stimulating hormone, which rises before ovulation, and helps stimulate the ovary follicles, was associated with thicker gray matter.
Progesterone, which rises after ovulation, was associated with increased tissue and decreased cerebrospinal fluid volume.

What this means for the person driving the brain is unknown, but the research lays the groundwork for future studies, and perhaps understanding the causes of unusual but severe period-related mental health problems.
Although we do not currently report functional consequences or correlates of structural brain changes, our findings may have implications for hormone-driven alterations in behavior and cognition," the researchers wrote.
Investigation of brain-hormone relationships across networks is necessary to understand human nervous system functioning on a daily basis, during hormone transition periods, and across the human lifespan.

https://onlinelibrary.wiley.com/doi/10.1002/hbm.26785

Part 2

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Comment by Dr. Krishna Kumari Challa on November 4, 2024 at 9:23am

Scientists Found Structural, Brain-Wide Changes During Menstruation

The constant ebb and flow of hormones that guide the menstrual cycle don't just affect reproductive anatomy. They also reshape the brain, and a study has given us insight into how this happens.

 A team of researchers tracked 30 women who menstruate over their cycles, documenting in detail the structural changes that take place in the brain as hormonal profiles fluctuate.

The results, published in a peer-reviewed study in July this year, suggest that structural changes in the brain during menstruation may not be limited to those regions associated with the menstrual cycle.

"These results are the first to report simultaneous brain-wide changes in human white matter microstructure and cortical thickness coinciding with menstrual cycle-driven hormone rhythms," the researchers wrote.

Strong brain-hormone interaction effects may not be limited to classically known hypothalamic-pituitary-gonadal-axis (HPG-axis) receptor-dense regions."
People who menstruate will experience some 450 or so periods during the course of their lifetimes, so it would be nice to know the different effects they can have on the body, really.

However, although it is something that happens to half the world's population for half their lives, research has been somewhat lacking. Who knows why. Total mystery.
Part 1

Comment by Dr. Krishna Kumari Challa on November 3, 2024 at 12:19pm

Exactly What Happens When an Atom Splits in Two?

The word atom comes from Latin for indivisible. But don't let the name fool you.

A simulation by US theoretical physicists has provided the first fully microscopic characterization of the moment an atom snips in two, revealing fresh insights into an energetic event that came to define a new age in science and technology.

theoretical physicists from Los Alamos National Laboratory and the University of Washington (UW) break the fission process down into four steps.

In the first 10^-14 seconds (give or take), the introduction of a slow-moving neutron forces the nucleus to bulge and rearrange itself in what's described as a saddle point, making the atom look a little like a tiny peanut shell.

This is quickly followed by a far more rapid shift, referred to as saddle-to-scission, where the fragments of the fission process are established. This lasts around 5×10^-21 seconds.

Step three is even faster again, transforming in a relative blink of 10^-22 seconds. In what's called the scission, or neck rupture, the nucleus officially breaks apart.

In the final step, which takes a lazy 10^-18 seconds to unfold, the fission fragments pull themselves into shape and accelerate away, releasing neutrons and gamma rays and potentially generating other decay processes after a brief delay.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.242501

Comment by Dr. Krishna Kumari Challa on November 3, 2024 at 12:12pm

The real reason behind gout

 

Gout is often associated with drinking too much or not eating healthily enough, but new research suggests genetics play more of a factor in developing the arthritic condition than previously thought. The research, carried out by an international team of scientists, looked at genetic data collected from 2.6 million people across 13 different cohorts of DNA data. That number included 120,295 people with "prevalent gout".

By comparing the genetic codes of the people with gout against the people without, the team found 377 specific DNA regions where there were variations specific to having the condition – 149 of which hadn't been previously linked to gout.

While lifestyle and environmental factors are certainly still in play, the findings suggest genetics play a major role in determining whether or not someone gets gout – and the researchers think there may be more undiscovered genetic links still to be found, too.

Gout takes hold when there are high levels of uric acid in the blood, which then form sharp crystal needles in the joints. When the body's immune system starts to attack those crystals, it leads to significant pain and discomfort.

Genetics is important in every stage of that process, the researchers suggest. Particularly, it affects the likelihood of the body's immune system attacking the crystals, and in the way uric acid is transported around the body.

Gout can come and go, but there are treatments available – and the authors behind the new study think misconceptions can put people off getting those treatments. That's a real problem with cases of the condition rising and rising.

https://www.nature.com/articles/s41588-024-01921-5

Comment by Dr. Krishna Kumari Challa on November 2, 2024 at 11:44am

Drone with its own 'nervous system' trialed by scientists

Scientists are testing a drone fitted with its own "nervous system" which they claim can keep it operating in the sky for longer. The system, made of optical fibers, reduces the frequency it needs to land for inspection.

Cargo-carrying drones are required to make regular pitstops for manual safety checks, which limits its use and can increase operating costs.

The optical fiber system developed by researchers makes drones more efficient by continuously monitoring its structural health just like nerves in the body.

This is a kind of nervous system for drones. 

It sends back real-time information using light—rather than electricity—which avoids problems that electronic systems have with interference from radio frequencies.

This system not only reduces the burden on ground crews but also ensures that drones can operate more safely and efficiently.

The system uses a unique technique called optical speckle which projects specific images dependent on what the optical fiber nervous system feels. These can be interpreted using AI to assess the health of the drone.

This speckle system keeps track of the stresses and strains on the drone, helping ground crews spot issues early without needing to land the drone as often for inspections.

Comment by Dr. Krishna Kumari Challa on November 2, 2024 at 11:26am

This is important because it tells us that government leaders do have the power to reduce crop burning. If they had more resources, they would probably be capable of reducing pollution to a larger extent."

The problem of air pollution from crop burning is especially prevalent at the border between India and Pakistan, where there is a lack of coordination between jurisdictions, the researchers added.

As part of the study, the researchers also examined the effects of crop-burning pollution on infant and child mortality and estimated that that 1.5 to 2.7 deaths per 1,000 children could be prevented if action were taken to reduce crop fires.

The researchers hope that this paper can contribute to the public debate on how to address this widespread problem and how to solve this selfishness problem.

Government leaders can explore punishment, incentives, information campaigns and many other initiatives that will encourage farmers to find alternative solutions to burning if they leave their "I, me , myself" thoughts .

Gemma Dipoppa et al, Bureaucrat incentives reduce crop burning and child mortality in South Asia, Nature (2024). DOI: 10.1038/s41586-024-08046-z

Part 2

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