Comment

Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 9:55am

"Our analysis does not support the widespread belief that increased affluence is the main driver of increased carbon emissions at the global level. It is definitely an important factor, but neglecting population growth leads to a skewed and misleading vision of reality."

"Developed nations with stable or declining populations should hence quit fighting these trends and instead embrace them. Just as a small population growth in rich countries can drive big emission increases, a population decrease in rich countries could have big emission-related benefits going forward," says Giangiacomo Bravo.

More information: Lucia Tamburino et al, An Analysis of Three Decades of Increasing Carbon Emissions: The Weight of the P Factor, Sustainability (2023). DOI: 10.3390/su15043245

Part 3

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Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 9:54am

The World Bank's four income groups

The World Bank has four classifications of income for the world's countries: low, lower-middle, upper-middle and high income. These are based on the respective country's gross national income (GNI) per capita.

The current figures apply to the year 2021, when 28 countries are defined as low-income countries, 54 as lower-middle, 54 as upper-middle and 81 as high-income countries.

Analysis of 30 years of emission data

The basis for Giangiacomo Bravo's statement is the analysis of 30 years of emission data for all the world's countries that he and two research colleagues have carried out. By splitting the countries into four income groups according to the World Bank's standard classification, the researchers were able to confirm that the contribution of low-income countries to emission increase is indeed limited. However, they also found that:

• Population is growing in all four income groups.
• The largest contribution to global carbon emissions comes from the upper-middle group.
• Population growth is the main driver of increased emissions in all income groups except the upper-middle one.
• The successful reduction in per capita emissions that occurred in high-income countries was nullified by the parallel increase in population in the same group.

Part 2

Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 9:54am

Population growth is the main driver of increased carbon emissions, study finds

The richest countries emit more carbon dioxide than the rest of the world combined, while population is only growing in the poorest countries. These are two widespread notions that argue for focusing on reducing emissions per capita in order to mitigate climate change. But this is not entirely true on the light of data from the last 30 years, new research published in the journal Sustainability shows.

A dominant narrative in the climate change debate is that addressing population is not relevant for mitigation. This is because the population is only growing in the poorest countries, whose contribution to global carbon emissions is negligible, the reasoning goes. The largest emissions come instead from rich countries where the population no longer grows.

"This way of reasoning is not correct. Our thorough analysis suggests that climate change mitigation strategies should address population along with per capita consumption and technological innovation. A comprehensive approach to the problem is needed," says Giangiacomo Bravo, professor at Linnaeus University.

Part 1

Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 9:47am

Using superconductors to move people, cargo and energy through one combined system

The promise of superconductivity for electrical power transmission and transportation has long been held back by high costs. Now researchers  have demonstrated a way to cut the cost and upend both the transit and energy transport sectors by using superconductors to move people, cargo and energy along existing highway infrastructure.

The combined system would not only lower the cost of operating each system but would also provide a way to store and transport liquified hydrogen, an important future source of clean energy. The liquified hydrogen would be used to cool the superconductor guideway as it is stored and transported, reducing the need for a separate specialized pipeline system capable of cooling the fuel to 20 degrees Kelvin, or minus 424 Fahrenheit. The concept, described in a paper published on April 24, 2023 in the journal APL Energy, suggests a future in which air travel and traditional freight transport could become obsolete, replaced by a "super system" allowing personal and commercial vehicles to travel at speeds up to 400 miles an hour—maybe even twice that fast.

Researchers built a model to demonstrate the key technical aspect of the concept—levitating a magnet above a superconductor guideway. Liquified nitrogen was used to cool the superconductors in the model; Researchers say future models will use hydrogen.

Vehicles with magnetized undercarriages—trains, cargo trucks, even personal vehicles—would enter the superconductor guideway, levitating and moving at high speed to reach their destinations. After leaving the guideway, vehicles would continue their trips powered by traditional electric or internal combustion motors.

People would be able to travel at their own convenience while enjoying the time-saving benefits of high-speed trains and air travel.

Fuel or electrical power consumption would drop dramatically while the car or truck was on the superconductor guideway, reducing both the cost and the environmental footprint.

Oleksii Vakaliuk et al, A multifunctional highway system incorporating superconductor levitated vehicles and liquefied hydrogen, APL Energy (2023). DOI: 10.1063/5.0139834. pubs.aip.org/aip/ape/article/1/1/016107/2884934

Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 9:20am

It's not as difficult as you think to shout upwind, shows study

For years, people have been wondering why it feels so difficult to shout upwind. The sensation is common enough to have found its way into an idiom about not being understood. But a scientific explanation for the phenomenon is  - there wasn't been one!

A research team showed that our common sense understanding of this situation is wrong. It isn't harder to shout into the wind; it's just harder to hear yourself.

In fact, acousticians have long known that sound carries better within the first 100 meters upwind. Many people have noticed that a siren sounds louder as it approaches and then quieter as it moves away. The mechanics behind this is similar to the Doppler effect, in which a sound changes frequency as it moves.

Research had confirmed that wind doesn't affect the emanation pattern of speech, so there was no reason why shouting into the wind would be difficult.

Their results were surprising but simple: it's harder for people to hear themselves when shouting upwind.

When someone shouts upwind, their ears are situated downwind from their mouth, which means that their ears receive less sound—it's harder from them to hear their shout than when there's no wind.

The same thing happens when someone is moving quickly even if there's no wind blowing—if you're cycling, for example. As a person bikes, their motion generates a wind around their head even in stationary air, and they end up shouting because they can't hear their own voice well.

So be careful what you shout upwind, for others might hear you just fine, even if you don't. This information is particularly useful for people who work with sound, such as musicians.

Ville Pulkki et al, Perceived difficulty of upwind shouting is a misconception explained by convective attenuation effect, Scientific Reports (2023). DOI: 10.1038/s41598-023-32306-z

Comment by Dr. Krishna Kumari Challa on April 24, 2023 at 10:29am

eHighway - solution for electrified road freight transport

Comment by Dr. Krishna Kumari Challa on April 23, 2023 at 11:21am

Stuck stem cells cause grey hair

Hair turns grey when melanocyte stem cells in the hair follicle fail to mature into thei... — at least that’s true in mice, and humans have similar cells. Scientists had thought that hair greys because the follicle runs out of melanocytes. A team tracked individual cells in mice over two years, which revealed that melanocytes travel up and down the hair follicle and switch back and forth between mature and young states. When the cells become stuck and stop making this journey, they stop receiving the signal to produce pigment.

Unlike embryonic stem cells, which develop into all sorts of different organs, adult stem cells have a more set path. The melanocyte stem cells in our hair follicles are responsible for producing and maintaining the pigment in our hair.

Each hair follicle keeps immature melanocyte stem cells in storage. When they’re needed, those cells travel from one part of the follicle to another, where proteins spur them to mature into pigment-producing cells, giving hair its hue.

Scientists assumed that gray hair was the result of that pool of melanocyte stem cells running dry. However, previous studies with mice made  scientists wonder if hair could lose its pigment even when stem cells are still present.

To learn more about stem cell behavior throughout different phases of hair growth, the researchers spent two years tracking and imaging individual cells in mouse fur. To their amazement, the stem cells traveled back and forth within the hair follicle, transitioning into their mature, pigment-producing state and then out of it again.

But as time wore on, the melanocyte cells couldn’t keep up the double act. A hair falling out and growing back takes a toll on the follicle, and eventually, the stem cells stopped making their journey, and thus, stopped receiving protein signals to make pigment. From then on, the new hair growth didn’t get its dose of melanin.

The researchers further explored this effect by plucking hairs from mice, simulating a faster hair growth cycle. This “forced aging” led to a buildup of melanocyte stem cells stuck in their storage place, no longer producing melanin. The mice’s fur went from dark brown to salt-and-pepper.

While the study was conducted with rodents, the researchers say their findings should be relevant to how human hair gets and loses its color. What’s more, they hope their findings could be a step toward preventing or reversing the graying process.

https://www.nature.com/articles/s41586-023-05960-6.epdf?sharing_tok...

Comment by Dr. Krishna Kumari Challa on April 21, 2023 at 12:43pm

Dendrites are the traffic lights of our nervous system. If an action potential is significant enough, it can be passed on to other nerves, which can block or pass on the message.

This is the logical underpinnings of our brain – ripples of voltage that can be communicated collectively in two forms: either an AND message (if x and y are triggered, the message is passed on); or an OR message (if x or y is triggered, the message is passed on).

Arguably, nowhere is this more complex than in the dense, wrinkled outer section of the human central nervous system; the cerebral cortex. The deeper second and third layers are especially thick, packed with branches that carry out high order functions we associate with sensation, thought, and motor control.

It was tissues from these layers that the researchers took a close look at, hooking up cells to a device called a somatodendritic patch clamp to send active potentials up and down each neuron, recording their signals.

There was a 'eureka' moment when  scientists saw the dendritic action potentials for the first time.

To ensure any discoveries weren't unique to people with epilepsy, they double checked their results in a handful of samples taken from brain tumors.

While the team had carried out similar experiments on rats, the kinds of signals they observed buzzing through the human cells were very different.

More importantly, when they dosed the cells with a sodium channel blocker called tetrodotoxin, they still found a signal. Only by blocking calcium did all fall quiet.

Finding an action-potential mediated by calcium is interesting enough. But modelling the way this sensitive new kind of signal worked in the cortex revealed a surprise.

In addition to the logical AND and OR-type functions, these individual neurons could act as 'exclusive' OR (XOR) intersections, which only permit a signal when another signal is graded in a particular fashion.

More work needs to be done to see how dCaAPs behave across entire neurons, and in a living system. Not to mention whether it's a human-thing, or if similar mechanisms have evolved elsewhere in the animal kingdom.

https://www.science.org/doi/10.1126/science.aax6239

Part 2

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Comment by Dr. Krishna Kumari Challa on April 21, 2023 at 12:40pm

A First-of-Its-Kind Signal Has Been Detected in The Human Brain

Scientists have recently identified a unique form of cell messaging occurring in the human brain that's not been seen before.

Excitingly, the discovery hints that our brains might be even more powerful units of computation than we realized.

In 2020, researchers  reported a mechanism in the brain's outer cortical cells that produces a novel 'graded' signal all on its own, one that could provide individual neurons with another way to carry out their logical functions.

By measuring the electrical activity in sections of tissue removed during surgery on epileptic patients and analyzing their structure using fluorescent microscopy, the neurologists found individual cells in the cortex used not just the usual sodium ions to 'fire', but calcium as well.

This combination of positively charged ions kicked off waves of voltage that had never been seen before, referred to as a calcium-mediated dendritic action potentials, or dCaAPs.

Brains – especially those of the human variety – are often compared to computers. The analogy has its limits, but on some levels they perform tasks in similar ways.

Both use the power of an electrical voltage to carry out various operations. In computers it's in the form of a rather simple flow of electrons through intersections called transistors.

In neurons, the signal is in the form of a wave of opening and closing channels that exchange charged particles such as sodium, chloride, and potassium. This pulse of flowing ions is called an action potential.

Instead of transistors, neurons manage these messages chemically at the end of branches called dendrites.

"The dendrites are central to understanding the brain because they are at the core of what determines the computational power of single neurons.

Part 1

Comment by Dr. Krishna Kumari Challa on April 21, 2023 at 12:28pm

Mosquito Saliva Can Actually Suppress Our Immune System, Study Finds

We know mosquitoes are a serious threat to our health as human beings– in fact, they're the world's deadliest animal, with mosquito-borne diseases responsible for more than a million deaths a year.

And it's not just their bites that we need to worry about. New research shows how the saliva of a mosquito carrying the  dengue virus is loaded with a substance that may suppress our immune system response and increase the risk of infection.

Through three separate analysis methods, scientists identified a specific type of viral RNA, or chemical messenger, called sfRNA in the infected mosquito saliva. It essentially blocks the defense mechanisms the human body puts up against infection.

It's incredible that the virus can hijack these molecules so that their co-delivery at the mosquito bite site gives it an advantage in establishing an infection.

These findings provide new perspectives on how we can counteract dengue virus infections from the very first bite of the mosquito.

The sfRNA is loaded in membrane compartments called extracellular vesicles, ready for delivery. The dengue virus appears to "subvert mosquito biology", in the words of the researchers, to give it a better chance of spreading. In tests on immortalized cell lines, the team confirmed that this sfRNA payload did indeed increase virus infection levels – laying the groundwork so that the human body isn't quite so well prepared for attack. These sfRNAs have been spotted before in insect-borne viruses, including Zika and yellow fever. Their role, more generally, seems to be to get in the way of the chemical signaling used by the body as the virus replicates.

Right now, there's no way of treating the virus, only methods for managing the symptoms. While we're still some way from a drug to treat dengue, understanding more about it and how it spreads is essential in fighting it.

https://journals.plos.org/plospathogens/article?id=10.1371/journal....

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