Motivation depends on how the brain processes fatigue

How do we decide whether or not an activity which requires work is 'worth the effort'? Researchers  have shown that the willingness to work is not static, and depends upon the fluctuating rhythms of fatigue.

Fatigue—the feeling of exhaustion from doing effortful tasks—is something we all experience daily. It makes us lose motivation and want to take a break. Although scientists understand the mechanisms the brain uses to decide whether a given task is worth the effort, the influence of fatigue on this process is not yet well understood.

The research team conducted a study to investigate the impact of fatigue on a person's decision to exert effort. They found that people were less likely to work and exert effort—even for a reward—if they were fatigued. The results are published in Nature Communications.

Intriguingly, the researchers found that there were two different types of fatigue that were detected in distinct parts of the brain. In the first, fatigue is experienced as a short-term feeling, which can be overcome after a short rest. Over time, however, a second, longer term feeling builds up, stops people from wanting to work, and doesn't go away with short rests.

Tanja Müller et al, Neural and computational mechanisms of momentary fatigue and persistence in effort-based choice, Nature Communications (2021). DOI: 10.1038/s41467-021-24927-7

Dark mode may not save battery life as much as anticipated

When Android and Apple operating system updates started giving users the option to put their smartphones in dark mode, the feature showed potential for saving the battery life of newer phones with screens that allow darker-colored pixels to use less power than lighter-colored pixels.

But dark mode is unlikely to make a big difference to battery life with the way that most people use their phones on a daily basis, says a new study by  researchers.

That doesn't mean that dark mode can't be helpful, though.

 Researchers found that switching from light mode to dark mode saves only 3%-9% power on average for several different OLED smartphones.

This percentage is so small that most users wouldn't notice the slightly longer battery life. But the higher the brightness when switching from light mode to dark mode, the higher the energy savings.

Pranab Dash et al, How much battery does dark mode save?, Proceedings of the 19th Annual International Conference on Mobile Systems, Applications, and Services (2021). DOI: 10.1145/3458864.3467682

https://techxplore.com/news/2021-07-dark-mode-battery-life.html?utm...

More carbon emissions will kill more people; here's how many

A just-published study coins a new metric: the "mortality cost of carbon." That is, how many future lives will be lost—or saved—depending on whether we increase or decrease our current carbon emissions. If the numbers hold up, they are quite high. The study was published recently in the journal Nature Communications.

Researchers saw a major gap in current estimates of the social cost of carbon—the dollar figure that economists attach to each ton of emissions, based on future damages it is expected to inflict. A complex and highly malleable number, the social cost of carbon underpins how governments worldwide formulate climate policies,  by suggesting how much we should be willing to pay today in order to avert damages in the future. Yet, while recent studies project that climate change will cause millions of premature deaths, current estimates of the social cost of carbon rely on outdated research that does not include those projections. Scientists now attempts to add in the new data.

Based on the decisions made by individuals, businesses or governments, this tells you how many lives will be lost, or saved. It quantifies the mortality impact of those decisions. It brings this question down to a more personal, understandable level.

Assuming that emissions continue to increase on their current high path, researchers came up with a number: 2.26×10^-4, or 0.000226 excess deaths this century per metric ton of carbon dioxide emitted beyond the current rate of emissions. That is: For every 4,434 metric tons of CO₂ that we add beyond the 2020 rate of emissions, we will kill one person. 

This implies that we must cut emissions in a big way now, and reach full decarbonization by 2050. The result would be only 2.4 degrees of warming by 2100. As a result, by scientists' calculation, excess deaths would drop to 9 million by 2100—a saving of 74 million lives.

All these figures are subject to political finagling.

https://news.climate.columbia.edu/2021/07/29/more-carbon-emissions-...

New exotic matter particle, a tetraquark, discovered

Yesterday  the LHCb experiment at CERN has presented a new discovery at the European Physical Society Conference on High Energy Physics (EPS-HEP). The new particle discovered by LHCb, labeled as T_cc⁺, is a tetraquark—an exotic hadron containing two quarks and two antiquarks. It is the longest-lived exotic matter particle ever discovered, and the first to contain two heavy quarks and two light antiquarks.

Quarks are the fundamental building blocks from which matter is constructed. They combine to form hadrons, namely baryons, such as the proton and the neutron, which consist of three quarks, and mesons, which are formed as quark-antiquark pairs. In recent years a number of so-called exotic hadrons—particles with four or five quarks, instead of the conventional two or three—have been found. The present  discovery is of a particularly unique exotic hadron.

The new particle  contains two charm quarks and an up and a down antiquark. 

https://home.cern/news/news/physics/twice-charm-long-lived-exotic-p...

Water transformed into shiny, golden metal

Electrons from a droplet of sodium and potassium turn water into a metallic material that conducts electricity.

Researchers have transformed water into a metallic material by forming a thin layer of water around electron-sharing alkali metals. The water stayed in a metallic state for only a few seconds, but the experiment did not require the high pressures that are normally needed to turn non-metallic materials into electrically conductive metals. Scientists say that seeing the water take on a golden shine was a highlight of their career, and a reminder that science can be fun.

Study: COVID-19 does not enter DNA

Researchers are refuting claims that COVID-19 corona virus can enter a person's DNA.

The researchers say the claims have led to "scaremongering" and people should not hesitate to be vaccinated.

Research published in Cell Reports showed there was no evidence of COVID-19—or the Pfizer or AstraZeneca vaccines—entering DNA.

The evidence refutes this concept being used to fuel vaccine hesitancy.

Scientists conducted the research to assess now widely spread findings, published in the Proceedings of the National Academy of Sciences, suggesting positive COVID-19 tests long after recovery are due to the virus being incorporated into DNA.

Researchers now looked into their claims that the human cells and machinery turned COVID-19 RNA into DNA, causing permanent mutations.

They assessed the claims in cells grown in the laboratory, conducted DNA sequencing and found no evidence of COVID-19 in DNA.

From a public health point of view, scientists affirmed  that there are no concerns that the virus or vaccines can be incorporated into human DNA.

Nathan Smits et al, No evidence of human genome integration of SARS-CoV-2 found by long-read DNA sequencing, Cell Reports (2021). DOI: 10.1016/j.celrep.2021.109530

https://medicalxpress.com/news/2021-07-covid-dna.html?utm_source=nw...

Solar-powered microbes to feed the world?

Researchers show that protein from microbes uses a fraction of the resources of conventional farming

An international research team has shown that using solar-panels to produce microbial protein -- which is rich not just in proteins but also in other nutrients -- is more sustainable, efficient and environmentally friendly than growing conventional crops. This method uses solar energy, land, nutrients, and carbon dioxide from the air.

Using computer simulations drawing directly from laboratory results, the researchers modelled large-scale microbial food production facilities, which use solar energy, air, water, and nutrients to grow microbes. The protein-rich biomass is harvested and processed, and the resulting powder can be used as feed for animals, or as food for people. The study carried out an analysis of the energy requirements for each step, from the very start to the end product, taking into account: electricity generation (from solar panels), electrochemical production of energy-rich substrate for the microbes, microbe cultivation, harvesting, and processing the protein-rich biomass. Several types of microbes and growth strategies were compared in order to identify the most efficient.

The study found that for each kilo of protein produced, solar-powered microbes require only 10% of the land area compared to even the most efficient plant crop -- soybean. The study calculated that even in northern climates with less sunshine, the yields of solar-powered microbial foods could far outproduce staple crops, while minimizing water and fertilizer use. Importantly, this production could also be located in regions not suitable for agriculture, such as deserts.

Dorian Leger, Silvio Matassa, Elad Noor, Alon Shepon, Ron Milo, Arren Bar-Even. Photovoltaic-driven microbial protein production can use land and sunlight more efficiently than conventional crops. Proceedings of the National Academy of Sciences, 2021; 118 (26): e2015025118 DOI: 10.1073/pnas.2015025118

https://www.sciencedaily.com/releases/2021/07/210730104303.htm

Fewer citations for female authors

Research papers published by women in elite medical journals are half as likely to be cited as are similar articles authored by men, a study of citation data has found. The work, which looked at more than 5,554 articles published between 2015 and 2018, “shows just how much impact unconscious biases can have”, says oncologist Reshma Jagsi. Citations are considered a key measure of a paper’s importance, and are often taken into account by those who make hiring and funding decisions.

Gender Disparity in Citations in High-Impact Journal Articles

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/278161...

Eternal Change for No Energy: A Time Crystal Finally Made Real

“Neuroprosthesis” Restores Words to Man with Paralysis

Why wildfires have gotten worse -- and what we can do about it

What causes déjà vu?

A Fully Autonomous Swarm of Gas-Seeking Nano Quadcopters in Cluttered Environments

Researchers have developed a swarm of autonomous, tiny drones that is able to localize gas sources in unknown, cluttered environments. Bio-inspired AI allows the drones to tackle this complex task without any external infrastructure.

Some birds steal hair from living mammals

A new paper in the journal Ecology documents this phenomenon, which the authors call “kleptotrichy,” from the Greek roots for “theft” and “hair.” The authors found only a few descriptions of the behavior in the scientific literature but came up with dozens more examples in online videos posted by birders and other bird enthusiasts. In almost all the videorecorded cases, the thief is a titmouse plucking hair from a cat, dog, human, raccoon, foxes, or in one case, porcupine.

A Bathing Suit That Doesn’t Get Wet

Mice treated with this cytokine lose weight by 'sweating' fat

 Treating obese mice with the cytokine known as TSLP led to significant abdominal fat and weight loss compared to controls, according to new research published recently  in Science.

The fat loss was not associated with decreased food intake or faster metabolism. Instead, the researchers discovered that TSLP stimulated the immune system to release lipids through the skin’s oil-producing sebaceous glands.

This was a completely unforeseen finding, but researchers have demonstrated that fat loss can be achieved by secreting calories from the skin in the form of energy-rich sebum.

To examine whether TSLP could potentially play a role in the control of oil secretion in humans, the researchers then examined TSLP and a panel of 18 sebaceous gland-associated genes in a publicly-available dataset. This revealed that TSLP expression is significantly and positively correlated with sebaceous gland gene expression in healthy human skin.

The study authors write that, in humans, shifting sebum release into “high gear” could feasibly lead to the “sweating of fat” and weight loss.

Ruth Choa, Junichiro Tohyama, Shogo Wada, Hu Meng, Jian Hu, Mariko Okumura, Rebecca M. May, Tanner F. Robertson, Ruth-Anne Langan Pai, Arben Nace, Christian Hopkins, Elizabeth A. Jacobsen, Malay Haldar, Garret A. FitzGerald, Edward M. Behrens, Andy J. Minn, Patrick Seale, George Cotsarelis, Brian Kim, John T. Seykora, Mingyao Li, Zoltan Arany, Taku Kambayashi. Thymic stromal lymphopoietin induces adipose loss through sebum hypersecretion. Science, 2021; 373 (6554): eabd2893 DOI: 10.1126/science.abd2893

https://www.sciencedaily.com/releases/2021/07/210729143412.htm

Lake Huron Sinkhole gives Clues to Oxygen Production on Early Earth

An international research team is proposing that increasing day length on the early Earth may have boosted the amount of oxygen released by photosynthetic cyanobacteria, thereby shaping the timing of Earth’s oxygenation. The rise of oxygen levels early in Earth’s history paved the way for life as we know it. The team's conclusion was inspired by a study of present-day microbial communities growing under extreme conditions at the bottom of a submerged Lake Huron sinkhole, about 80 feet below the water’s surface.

 Possible link between Earth's rotation rate and oxygenation, Nature Geoscience (2021). DOI: 10.1038/s41561-021-00784-3 , www.nature.com/articles/s41561-021-00784-3

https://phys.org/news/2021-08-lake-huron-sinkhole-oxygen-early.html...

Muscles are important, but stiff tendons are the secret ingredient for high-speed performance

You might be surprised to learn that most of the explosive power displayed by  elite athletes doesn't come from their muscles, or even from their minds—it comes from somewhere else.

Muscles are important, but the real secret is using training and technique to store and reuse elastic energy in the best way possible—and that means making the most of your tendons. By understanding how this power is produced, we can help people walk, run and jump into older age and how to walk again after injury or illness.

Muscles are remarkably powerful. The average human calf muscle weighs less than 1 kilogram, but can lift a load of 500kg. In some cases, our calf muscles have even been shown to handle loads approaching a ton(1,000kg)!

But muscles have a major performance issue: they can't produce much force when they're shortening at high speed. In fact, when we move at our fastest, muscles can't theoretically shorten fast enough to help us at all—so how is it that we can move so quickly?

part 1

**

Muscles are strong, but slow

Muscles produce most of their force through the interactions of two proteins: actin and myosin. The rotating, globular "head" region of the long myosin filament attaches to the rod-like actin to pull it along in a sweeping motion, like an oar producing force to pull a boat along the water. So actin and myosin filaments form powerful mini motors.

Trillions of these mini motors together the large forces we need every day to walk upstairs, carry our shopping bags, or take the lid off a jar.

The head region of myosin is only 20 nanometres long. It's so small that there's no point comparing its size to a human hair, because it would barely even cross a handful of DNA molecules laid side by side.

Because it's so short and only pulls actin a small distance in each stroke, a large number of strokes are needed to shorten a muscle by any distance. It's like using first gear to get up a hill in a car or on a bike—good for force, but not for speed.

And the faster the muscle shortens, the less time each myosin is attached to actin, which reduces force even further. At a certain shortening speed, muscles can't produce any force at all.

We can measure the power athletes produce during running and jumping, and we can estimate the power a muscle should produce by its size and the type of fibers it contains. When we compare these two values, we find that muscles can't even produce half the power generated in sprinting or vertical jumping. And in overarm throwing, muscles can produce only15% of the total power.

So if the muscles aren't producing the power to move a body at high speed, where is it coming from? Humans, like most other animals on Earth, make use of an "energy return system": something that can store energy and release it rapidly when needed.

Our energy return systems are made of a relatively long, stretchy tendon attached to a strong muscle. When the muscle produces force it stretches the tendon, storing elastic energy. The subsequent recoil of the tendon then generates a power far superior to our muscles. Our tendons are power amplifiers.

There are several techniques we can use to increase energy storage. The most important is to first move in the opposite direction to the desired movement (a "countermovement") so the muscle force is already high when the proper movement begins. Most of us learn this strategy when we're young, when we first dip down before we jump upwards, or we draw our bat or racquet backwards before swinging it forwards.

The technique we use is key to maximizing our elastic potential, and Olympic athletes spend years trying to optimize it.

Tendons that are stiffer or stretched further will store more energy and then recoil with greater power. During running, the greatest power is produced at the ankle joint, so it makes sense that sprint runners and the best endurance runners have stiffer Achilles' tendons than us mere mortals.

They also have the muscle strength to stretch them. We haven't yet accurately measured the stiffness of shoulder tendons in athletes, but we might assume they are built similarly.

part 2

The capacity to store and release elastic energy is partly determined by genetics, but it's also something we can improve through training. Not only can training improve your technique, heavy strength training and other methods can also make your tendons stiffer.

As we develop from childhood to adulthood, we learn to make better use of elastic energy to produce more power and use it more efficiently. As we age further, our tendon stiffness and power output decrease, and it costs us more energy to move.

People with less stiffness in their Achilles' tendon (and the accompanying lower strength in the calf muscles) have slower walking speeds. As walking speed is strongly associated with mortality and morbidity in the elderly, maintaining tendon stiffness may be important to our health and longevity.

The greatest power during walking, running and jumping is produced at the ankle joint. This is an important target for athletes, but also for anyone who wants to maintain their walking capacity as they age.

Good ways to keep your ankle muscles conditioned include calf raises on a step, squat to calf raise exercises, and walking up and down hills whenever you get the chance.

If you feel game, you might even join a gym and enjoy the numerous ways to strengthen your calf and Achilles' tendon, and lots of other muscles too.

https://medicalxpress.com/news/2021-08-muscles-important-stiff-tend...

https://theconversation.com/muscles-are-important-but-stiff-tendons...

part 3

Male fertility is declining, environmental toxins could be a reason

A wide range of factors—from obesity to hormonal imbalances to genetic diseases—can affect fertility. For many men, there are treatments that can help. But starting in the 1990s, researchers noticed a concerning trend. Even when controlling for many of the known risk factors, male fertility appeared to have been declining for decades. In 1992, a study found a global 50% decline in sperm counts in men over the previous 60 years. Multiple studies over subsequent years confirmed that initial finding, including a 2017 paper showing a 50% to 60% decline in sperm concentration between 1973 and 2011 in men from around the world. The science is consistent: Men today produce fewer sperm than in the past, and the sperm are less healthy. The question, then, is what could be causing this decline in fertility. Scientists have known for years that, at least in animal models, environmental toxic exposure can alter hormonal balance and throw off reproduction. Researchers can't intentionally expose human patients to harmful compounds and measure outcomes, but we can try to assess associations. As the downward trend in male fertility emerged, I and other researchers began looking more toward chemicals in the environment for answers. This approach doesn't allow us to definitively establish which chemicals are causing the male fertility decline, but the weight of the evidence is growing. A lot of this research focuses on endocrine disrupters, molecules that mimic the body's hormones and throw off the fragile hormonal balance of reproduction. These include substances like phthalates—better known as plasticizers—as well as pesticides, herbicides, heavy metals, toxic gases and other synthetic materials. Plasticizers are found in most plastics—like water bottles and food containers—and exposure is associated with negative impacts on testosterone and semen health.Herbicides and pesticides abound in the food supply and some—specifically those with synthetic organic compounds that include phosphorus—are known to negatively affect fertility. Air pollution surrounds cities, subjecting residents to particulate matter, sulfur dioxide, nitrogen oxide and other compounds that likely contribute to abnormal sperm quality. Radiation exposure from laptops, cellphones and modems has also been associated with declining sperm counts, impaired sperm motility and abnormal sperm shape. Heavy metals such as cadmium, lead and arsenic are also present in food, water and cosmetics and are also known to harm sperm health. Endocrine-disrupting compounds and the infertility problems they cause are taking a significant toll on human physical and emotional health. And treating these harms is costly.

https://theconversation.com/male-fertility-is-declining-studies-sho...

https://medicalxpress.com/news/2021-08-male-fertility-declining-env...

**

Deficiency in how gut microbiome-produced substances are detected in high blood pressure

In a new study  scientists have found that microbial genetic pathways are different in people suffering from hypertension.

The research also found that those with hypertension also have a deficiency in a newly identified target gene that senses gut microbiota-derived metabolites that lower BP.

If left untreated, hypertension, also referred to as high BP, can lead to stroke and, myocardial infarction, the main causes of death globally. Long-term, hypertension causes a stiffening of the arteries and the muscles of the heart, leading to heart failure. This is important as the research team also found in another recently published study that patients with heart failure, for which hypertension is a major risk factor, have a distinct gut microbiome composition.

The research team assessed human gut microbiota in the setting of high blood-pressure levels and heart failure to better understand the complex nature of these diseases. Changes in gut microbiome were particularly associated with bacteria that are known to produce short-chain fatty acids, substances their team has previously shown to ameliorate blood pressure and heart disease in mice.

The researchers found that the gut microbiome was mostly similar between normotensive and essential hypertensive groups, but the gut microbial gene pathways were different, suggesting major differences in the function of the microbiota.

They also found that hypertensive subjects have a deficiency in a new target gene that senses gut microbiota derived metabolites that lower blood pressure.

 Michael Nakai et al, Essential Hypertension Is Associated With Changes in Gut Microbial Metabolic Pathways, Hypertension (2021). DOI: 10.1161/HYPERTENSIONAHA.121.17288

Anna L. Beale et al, The Gut Microbiome of Heart Failure With Preserved Ejection Fraction, Journal of the American Heart Association (2021). DOI: 10.1161/JAHA.120.020654

https://medicalxpress.com/news/2021-08-deficiency-gut-microbiome-pr...

Traumatic brain injury research

How sex cells get the right genetic mix

Particles from paints, pesticides can have deadly impact

Hundreds of thousands of people around the world die too soon every year because of exposure to air pollution caused by our daily use of chemical products and fuels, including paints, pesticides, charcoal and gases from vehicle tailpipes, according to a new study.

Researchers calculated that air pollution caused by "anthropogenic secondary organic aerosol" causes 340,000-900,000 premature deaths. Those are tiny particles in the atmosphere that form from chemicals emitted by human activities.

The older idea was that to reduce premature mortality, you should target coal-fired power plants or the transportation sector. Yes, these are important, but this study is showing that if you're not getting at the cleaning and painting products and other everyday chemicals, then you're not getting at a major source.

Atmospheric researchers have long understood that particles in the atmosphere small enough to be inhaled can damage people's lungs and increase mortality. Studies have estimated that fine particle pollution, often called PM2.5, leads to 3-4 million premature deaths  globally per year, possibly more.

The new work suggests that a third broad category of chemicals—anthropogenic secondary organic pollutants—is a significant indirect source of deadly fine particles.

Benjamin A. Nault et al, Secondary organic aerosols from anthropogenic volatile organic compounds contribute substantially to air pollution mortality, Atmospheric Chemistry and Physics (2021). DOI: 10.5194/acp-21-11201-2021

https://phys.org/news/2021-08-particles-pesticides-deadly-impact.ht...

Cryptic transcription in mammalian stem cells linked to aging

Although visible signs of aging are usually unmistakable, unraveling what triggers them has been quite a challenge. Researchers have discovered that a cellular phenomenon called cryptic transcription, which had been previously described and linked to aging in yeasts and worms, is elevated in aging mammalian stem cells.

Researchers report in the journal Nature Aging that cryptic transcription occurs because a cellular mechanism that keeps it in check falls apart as cells get old. The findings suggest that strategies that control cryptic transcription could have pro-longevity effects.

In previous work, they showed that cryptic transcription in yeasts and worms is not only a marker of aging but also a cause. Reducing the amount of this aberrant transcription in these organisms prolonged their lifespan.

Cryptic transcription is a phenomenon that interferes with normal cellular processes. Normal gene transcription is a first step in the production of proteins. It begins in a specific location on the DNA called the promoter. This is where the protein coding gene begins to be transcribed into RNA, which is eventually translated into protein. Gene transcription is a well-regulated cellular process, but as cells age, they lose their ability to control it.

Promoters have a specific DNA sequence that identifies the starting point of the transcription process that is usually located preceding the actual protein coding sequence.

But promoter look-alike sequences do exist in other locations, including along the actual protein coding sequence, and they could start transcription and generate shorter transcripts, called cryptic transcripts.

worked with mammalian stem cells, which have shown to play a significant role in aging. They adapted a method to detect cryptic transcription to determine the level of this transcription in mice and human stem cells and cultured cells. When compared to young stem cells, older ones had increased cryptic transcription. They also looked into other aging cells and found that, in the majority of cells spanning a range of tissues, cryptic transcription was also elevated with age.

Altogether, these findings indicate that elevated cryptic transcription is a hallmark of mammalian aging. Young cells have mechanisms in place to prevent cryptic transcription. In aged mammalian cells, the researchers found that one such mechanisms, which involves limiting the access to chromatin, the material that makes up the chromosomes, is failing, facilitating the production of cryptic transcripts.

https://www.nature.com/articles/s43587-021-00091-x

https://researchnews.cc/news/8148/Cryptic-transcription-in-mammalia...

Driverless Tractor: India’s Innovation

Study reveals how smell receptors work

All senses must reckon with the richness of the world, but nothing matches the challenge faced by the olfactory system that underlies our sense of smell. We need only three receptors in our eyes to sense all the colors of the rainbow—that's because different hues emerge as light-waves that vary across just one dimension, their frequency. The vibrant colorful world, however, pales in comparison to the complexity of the chemical world, with its many millions of odors, each composed of hundreds of molecules, all varying greatly in shape, size and properties. The smell of coffee, for instance, emerges from a combination of more than 200 chemical components, each of which are structurally diverse, and none of which actually smells like coffee on its own.

To form a basic understanding of odorant recognition we need to know how a single receptor can recognize multiple different chemicals, which is a key feature of how the olfactory system works 

The olfactory system has to recognize a vast number of molecules with only a few hundred odour receptors or even less. It's clear that it had to evolve a different kind of logic than other sensory systems.

In a new study researchers offer answers to the decades-old question of odour recognition by providing the first-ever molecular views of an olfactory receptor at work.

The findings, published in Nature, reveal that olfactory receptors indeed follow a logic rarely seen in other receptors of the nervous system. While most receptors are precisely shaped to pair with only a few select molecules in a lock-and-key fashion, most olfactory receptors each bind to a large number of different molecules. Their promiscuity in pairing with a variety of odors allows each receptor to respond to many chemical components. From there, the brain can figure out the odor by considering the activation pattern of combinations of receptors.

 The structural basis of odorant recognition in insect olfactory receptors, Nature (2021). DOI: 10.1038/s41586-021-03794-8 , www.nature.com/articles/s41586-021-03794-8

https://phys.org/news/2021-08-reveals-receptors.html?utm_source=nwl...

Earth's energy budget is out of balance – here's how it's warming the climate

Energy can neither be created nor destroyed. That's a fundamental property of the universe.

Energy can be transformed, however. When the sun's rays reach Earth, they are transformed into random motions of molecules that you feel as heat. At the same time, Earth and the atmosphere are sending radiation back into space. The balance between the incoming and outgoing energy is known as Earth's "energy budget."

Our climate is determined by these energy flows. When the amount of energy coming in is more than the energy going out, the planet warms up.

That can happen in a few ways, such as when sea ice that normally reflects solar radiation back into space disappears and the dark ocean absorbs that energy instead. It also happens when greenhouse gases build up in the atmosphere and trap some of the energy that otherwise would have radiated away.

part 1

Virtually all the energy in the Earth's climate system comes from the sun. Only a tiny fraction is conducted upward from the Earth's interior.

On average, the planet receives 340.4 watts of sunshine per square meter. All sunshine falls on the daytime side, and the numbers are much higher at local noon.

Of that 340.4 watts per square meter:
99.9 watts are reflected back into space by clouds, dust, snow and the Earth's surface.
The remaining 240.5 watts are absorbed—about a quarter by the atmosphere and the rest by the surface of the planet. This radiation is transformed into thermal energy within the Earth system. Almost all of this absorbed energy is matched by energy emitted back into space. A tiny residual—0.6 watts per square meter—accumulates as global warming. That may not sound like much, but it adds up.
The atmosphere absorbs a lot of energy and emits it as radiation both into space and back down to the planet's surface. In fact, Earth's surface gets almost twice as much radiation from the atmosphere as it does from direct sunshine. That's primarily because the sun heats the surface only during the day, while the warm atmosphere is up there 24/7.

part 2

Earth's Delicate Energy Balance

Together, the energy reaching Earth's surface from the sun and from the atmosphere is about 504 watts per square meter. Earth's surface emits about 79% of that back out. The remaining surface energy goes into evaporating water and warming the air, oceans and land.

The tiny residual between incoming sunshine and outgoing infrared is due to the accumulation of greenhouse gases like carbon dioxide in the air. These gases are transparent to sunlight but opaque to infrared rays—they absorb and emit a lot of infrared rays back down.

Earth's surface temperature must increase in response until the balance between incoming and outgoing radiation is restored.

Doubling of carbon dioxide would add 3.7 watts of heat to every square meter of the Earth. Imagine old-fashioned incandescent night lights spaced every 3 feet over the entire world, left on forever.

At the current rate of emissions, greenhouse gas levels would double from preindustrial levels by the middle of the century.

Climate scientists calculate that adding this much heat to the world would warm Earth's climate by about 5 degrees Fahrenheit (3 C). Preventing this would require replacing fossil fuel combustion, the leading source of greenhouse gas emissions, with other forms of energy.

https://theconversation.com/earths-energy-budget-is-out-of-balance-...

part 4

Nearly 5 mn fewer girls to be born worldwide over next 10 years: study

An estimated 4.7 million fewer girls are expected to be born globally in the next 10 years because of sex-selective practices in countries with a cultural preference for male offspring, a trend that could undermine social cohesion in the long term, research showed on Tuesday. The research suggested that the projected shortfall in the number of girls being born will lead to a surplus of young men in around a third of the global population by 2030, which could lead to increased anti-social behaviour and violence. Sex-selective abortions have been on the rise for the past 40 years in countries throughout southeast Europe along with south and east Asia, with as-yet undetermined demographic impacts. To model what short- and long-term effect sex selection will have on societies, an international team of researchers analysed data from more than three billion births over the last 50 years. Focusing on 12 countries where the male-to-female ratio had increased since 1970 and another 17 where that ratio was at risk of increasing due to social or cultural trends, they simulated two scenarios.

The first assumed an increase in the rate of sex selection, based on statistical evidence.

The second scenario assumed increased sex selection in certain countries, based on observed trends and decreased fertility, but for which specific data were lacking.

In scenario 1, countries saw a shortfall of 4.7 million in the number of girls being born by 2030. For scenario 2, the figure jumped to more than 22 million globally by 2100.

Authors of the research, published in the BMJ medical journal, said the bias towards male offspring could lead to a "marriage squeeze" in affected countries.

"Fewer-than-expected females in a population could result in elevated levels of anti-social behaviour and violence, and may ultimately affect long-term stability and social sustainable development," they wrote.

The United Nations defines sex-selective practices alongside child marriage and female genital mutilation as harmful practices targeted under the Millennium Development Goals.

The authors of the new study called for better data collection of such practices in order to stamp them out, as well as wider education initiatives.

"A broader objective relates to the need to influence gender norms which lie at the core of harmful practices such as prenatal sex selection," they wrote.

"This calls for broader legal frameworks to ensure gender equality."

Source:  Agence France-Presse

New approach to information transfer reaches quantum speed limit

Researchers have  been investigating the theoretical constraints that will bound quantum technologies. One of the things researchers have discovered is that there are limits to how quickly quantum information can race across any quantum device.

These speed limits are called Lieb-Robinson bounds, and, for several years, some of the bounds have taunted researchers. For certain tasks, there was a gap between the best speeds allowed by theory and the speeds possible with the best algorithms anyone had designed. It's as though no car manufacturer could figure out how to make a model that reached the local highway limit.

But unlike speed limits on roadways, information speed limits can't be ignored when you're in a hurry—they are the inevitable results of the fundamental laws of physics. For any quantum task, there is a limit to how quickly interactions can make their influence felt (and thus transfer information) a certain distance away. The underlying rules define the best performance that is possible. In this way, information speed limits are more like the max score on an old school arcade game than traffic laws, and achieving the ultimate score is an alluring prize for scientists.

Now a team of researchers have found a quantum protocol that reaches the theoretical speed limits for certain quantum tasks. Their result provides new insight into designing optimal quantum algorithms and proves that there hasn't been a lower, undiscovered limit thwarting attempts to make better designs.

part1

Minh C. Tran et al, Optimal State Transfer and Entanglement Generation in Power-Law Interacting Systems, Physical Review X (2021). DOI: 10.1103/PhysRevX.11.031016

https://phys.org/news/2021-08-approach-quantum-limit.html?utm_sourc...

Unsurprisingly, the theoretical speed limit for sending information in a quantum device (such as a quantum computer) depends on the device's underlying structure. The new protocol is designed for quantum devices where the basic building blocks—qubits—influence each other even when they aren't right next to each other. In particular, the team designed the protocol for qubits that have interactions that weaken as the distance between them grows. The new protocol works for a range of interactions that don't weaken too rapidly, which covers the interactions in many practical building blocks of quantum technologies, including nitrogen-vacancy centers, Rydberg atoms, polar molecules and trapped ions.

Crucially, the protocol can transfer information contained in an unknown quantum state to a distant qubit, an essential feature for achieving many of the advantages promised by quantum computers. This limits the way information can be transferred and rules out some direct approaches, like just creating a copy of the information at the new location. (That requires knowing the quantum state you are transferring.)

In the new protocol, data stored on one qubit is shared with its neighbors, using a phenomenon called quantum entanglement. Then, since all those qubits help carry the information, they work together to spread it to other sets of qubits. Because more qubits are involved, they transfer the information even more quickly.

This process can be repeated to keep generating larger blocks of qubits that pass the information faster and faster. So instead of the straightforward method of qubits passing information one by one like a basketball team passing the ball down the court, the qubits are more like snowflakes that combine into a larger and more rapidly rolling snowball at each step. And the bigger the snowball, the more flakes stick with each revolution.

But that's maybe where the similarities to snowballs end. Unlike a real snowball, the quantum collection can also unroll itself. The information is left on the distant qubit when the process runs in reverse, returning all the other qubits to their original states.

When the researchers analyzed the process, they found that the snowballing qubits speed along the information at the theoretical limits allowed by physics. Since the protocol reaches the previously proven limit, no future protocol should be able to surpass it.

part2

Tips to tackle plastic pollution

Microwaving an ambulance. New technique could revolutionise how surfaces are disinfected
Microwave engineers, infectious disease specialists and polymer scientists have teamed up to create a novel microwave sterilization method that could revolutionize the way ambulances and hospitals are being disinfected.
At present, sterilization is done manually with conventional techniques that use chemicals. This can take around 30 to 40 minutes to disinfect a single ambulance.

During this time, the ambulance is out of action which puts increasing pressure on emergency services during busy times. The possibility of the new technique could drastically reduce the time it takes to get an ambulance safely back on the road to save lives.

In recent years, several other techniques have been proposed for disinfecting and sterilizing surfaces, ranging from hydrogen peroxide aerosols to UV irradiation and infrared radiation. However, these techniques have been shown to degrade surfaces over time, or to be harmful to humans if they are in close proximity. This has, so far, limited their long-term application.

In contrast, the new method works using electromagnetic waves, antennas, sensor beacons, and a liquid layer to rapidly heat-up and sterilize surfaces. Its automation means a person can easily operate the system from a safe distance rather than touching contaminated surfaces directly during cleaning.
The study used microwave beams emanating from antennas like those found in mobile smart phones and domestic Wi-Fi systems. The antennas allow the microwave radiation to be directed and focussed on locations where it is most needed.
K. Kossenas et al, A Methodology for Remote Microwave Sterilization Applicable to the Coronavirus and Other Pathogens using Retrodirective Antenna Arrays, IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology. DOI: 10.1109/JERM.2021.3077110
https://techxplore.com/news/2021-08-microwave-ambulance-technique-r...

When faces are partially covered, neither people nor algorithms are...

Artificial systems such as homecare robots or driver-assistance technology are becoming more common, and it's timely to investigate whether people or algorithms are better at reading emotions, particularly given the added challenge brought on by face coverings.

Using two CRISPR enzymes, a COVID diagnostic in only 20 minutes

Frequent, rapid testing for COVID-19 is critical to controlling the spread of outbreaks, especially as new, more transmissible variants emerge.

A research team is aiming to develop a diagnostic test that is much faster and easier to deploy than qRT-PCR. It has now combined two different types of CRISPR enzymes to create an assay that can detect small amounts of viral RNA in less than an hour.

While the new technique is not yet at the stage where it rivals the sensitivity of qRT-PCR, which can detect just a few copies of the virus per microliter of liquid, it is already able to pick up levels of viral RNA—about 30 copies per microliter—sufficient to be used to surveil the population and limit the spread of infections.

Liu, T.Y. et al. Accelerated RNA detection using tandem CRISPR nucleases. Nat Chem Biol (2021). DOI: 10.1038/s41589-021-00842-2

https://phys.org/news/2021-08-crispr-enzymes-covid-diagnostic-minut...

Antibody findings spark ideas for pan-coronavirus vaccine

Three epidemic or pandemic coronaviruses—SARS-CoV, MERS-CoV, & SARS-CoV-2—have spilled over from animals to cause deadly illness in humans in the past 20 years. Virus researchers are determined to discover a means to broadly safeguard people from the continuing threat of emerging coronaviruses.

Clues for creating such an overarching countermeasure might come from a rare type of human antibody that can neutralize several different coronaviruses. These antibodies have been detected in some people who have recovered from COVID-19.

A paper appearing Aug. 3 in the journal Science describes research on five such human monoclonal antibodies that can cross-react with a number of beta-coronaviruses. These antibodies target a structure, called stem helix, in the spike protein of these viruses. The spike protein is critical to the virus' ability to overtake host cells.

The stem helix in the spike protein has remained conserved during the evolution of certain coronaviruses. That means it is much less prone to genetic changes and is similar in various coronaviruses. These include those originating in bats that have become dangerous pathogens in people, and another subgenus that causes a serious human lung disease transmitted by dromedary camels, as well as a few other subgenera that cause simple common cold symptoms.

The researchers explain in their paper that they were interested in exploring antibodies that target highly conserved regions of the spike protein machinery that enable coronaviruses to fuse with the membrane of host cells. 

An antibody's ability to bind to the less mutable fusion machinery is what allows it to neutralize distantly related coronaviruses.

To find these sorts of antibodies, the researchers examined certain memory B cells from COVID-19 convalescent donors. Memory B cells are white blood cells that recognize and respond to pathogens that have tried to attack the body during a previous encounter.

part 1

Out of five promising antibodies that they isolated, the scientists decided to concentrate on one designated S2P6. Molecular structure analysis and functional studies showed that this human monoclonal antibody had impressive breadth: it was able to neutralize three different subgenera of beta-coronaviruses. The scientists observed that it did so by inhibiting the virus' ability to fuse with cell membranes.

The researchers went on to test if the S2P6 stem helix antibody could protect against SARS-CoV-2 by administering it to hamsters 24 hours before exposure. They found that this antibody reduced the viral load of SARS-CoV-2 by inhibiting entry of the virus and by enhancing additional anti-viral and virus-clearing cellular immune responses.

Studies of the plasma from pre-pandemic human samples, as well as from COVID-vaccinated and COVID-recovered individuals were also analyzed to see how frequently the stem-helix targeting antibodies appeared. They highest frequencies occurred in people who had recovered from COVID-19, then were later vaccinated. Overall, however, the data from this study shows that, while it does occur, it is relatively rare for SARS-CoV-2 to elicit plasma stem-helix antibody responses. The researchers hope that additional studies might reveal whether this is the case for antibodies that target other parts of the coronavirus fusion machinery or only for those that target the stem helix.

The researchers also looked at how the broadly reactive monoclonal antibodies studied in this project might have originated. Their findings suggest that they may have resulted from the priming of B memory cells through one of the common cold-inducing coronaviruses. Then the virus-specific B cells gained cross-reactivity through somatic mutations occurring during the body's immune response to a natural infection with another type of coronavirus.

The results from this study indicate that eliciting a sufficient quantity of stem helix antibodies through a standard vaccination development approach likely would be difficult. However, the researchers propose that recent computational protein-design advances for potential vaccine candidates against respiratory syncytial viruses and multiple influenza viruses might be adapted to try to induce broad beta coronavirus immunity and overcome the pan-coronavirus vaccine challenge.

Dora Pinto et al, Broad betacoronavirus neutralization by a stem helix–specific human antibody, Science (2021). DOI: 10.1126/science.abj3321

https://medicalxpress.com/news/2021-08-antibody-ideas-pan-coronavir...

Environmental impact of bottled water up to 3,500 times higher than tap water

The consumption of bottled water has been increasing sharply in recent years on a global scale. According to previous research, this trend can be partly explained by subjective factors like risk perception, taste, odor, lack of trust in public tap water quality and marketing by bottled water companies.

Environmental and health impacts are usually assessed separately due to the different methodologies applied and resulting outcomes. Environmental impacts can be estimated with a methodology called Life Cycle Assessment (LCA), while the consequences in human helath are estimated with an approach called Health Impact Assessment (HIA). This study has tried to overcome this methodological barrier for the first time by combining LCA and HIA in the same analysis.

The results of work done in Barcelona, Spain, showed that if the whole population of the city decided to shift to bottled water, the production required would take a toll of 1.43 species lost per year and cost of 83.9 million USD per year due to extraction of raw materials. This is approximately 1,400 times more impact in ecosystems and 3,500 times higher cost of resource extraction compared to the scenario where the whole population would shift to tap water.

The results results show that considering both the environmental and the health effects, tap water is a better option than bottled water, because bottled water generates a wider range of impacts.

Cristina M. Villanueva et al, Health and environmental impacts of drinking water choices in Barcelona, Spain: A modelling study, Science of The Total Environment (2021). DOI: 10.1016/j.scitotenv.2021.148884

https://phys.org/news/2021-08-environmental-impact-bottled-higher.h...

Microbes engineered to convert sugar into a chemical found in tires

The future environmental footprint of the tire industry could be substantially shrunk thanks to a new ecofriendly way found by researchers that harnesses bacteria to make a chemical used in synthetic rubber.

Each year, factories around the world churn out more than 12 million metric tons of the organic chemical 1,3-butadiene, which is used in tires, adhesives, sealants and other plastic and rubber products. They produce it by an energy-intensive process that relies on petroleum, which contributes to climate change.

Scientists have tried for many years to create 1,3-butadiene from more environmentally friendly starting materials by using specially designed microbes. But no one had previously succeeded in transforming a simple sugar such as glucose into the chemical in one easy step.

Now, by engineering bacteria to convert glucose into 1,3-butadiene,  researchers have devised a sustainable approach to rubber and plastic production. They constructed a novel artificial metabolic pathway and produced 1,3-butadiene directly from a renewable source—glucose. They first engineered a bacterial enzyme that could convert a biological compound that can be developed from glucose into 1,3-butadiene . The researchers then modified a strain of the bacterium Escherichia coli to use this enzyme and produce the chemical. Since 1,3-butadiene is a gas at room temperature, it can be easily captured as the bacteria continue to divide and grow.

Yutaro Mori et al, Direct 1,3-butadiene biosynthesis in Escherichia coli via a tailored ferulic acid decarboxylase mutant, Nature Communications (2021). DOI: 10.1038/s41467-021-22504-6

https://phys.org/news/2021-08-microbes-sugar-chemical.html?utm_sour...

Freeze-Dried Mouse Sperm Sent by Postcard Produces Baby Mice

Rather than relying on samples that need to be shipped in glass vials and on ice, researchers have developed a new method that allows mouse sperm to be sent easily at room temperature using standard mail delivery.

The new method, detailed in a study published today (August 5) in iScience, builds on the team’s previous work, which involved sending dehydrated mouse sperm stored in glass ampoules to the International Space Station to study how radiation affects mammalian cells. Drying the samples, the authors say, does away with the need for cold storage, and they’ve since refined the method further so that they can store sperm from thousands of different mouse strains in a single three-ring binder.

https://www.cell.com/iscience/fulltext/S2589-0042(21)00783-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004221007835%3Fshowall%3Dtrue

https://www.the-scientist.com/news-opinion/freeze-dried-mouse-sperm...

 Machu Picchu older than previously thought

Machu Picchu, the famous 15th-century Inca site in southern Peru, is up to several decades older than previously thought, according to a new study .

Until now, estimates of Machu Picchu's antiquity and the length of its occupation were based on contradictory historical accounts written by Spaniards in the period following the Spanish conquest.

Researchers used  used accelerator mass spectrometry (AMS)—an advanced form of radiocarbon dating—to date human remains recovered during the early 20th century at the monumental complex and onetime country estate of Inca Emperor Pachacuti located on the eastern face of the Andes Mountains.

Their findings, published in the journal Antiquity, reveal that Machu Picchu was in use from about A.D. 1420 to A.D. 1530—ending around the time of the Spanish conquest—making the site at least 20 years older than the accepted historical record suggests and raising questions about our understanding of Inca chronology.

Historical sources dating from the Spanish invasion of the Inca Empire indicate that Pachacuti seized power in A.D. 1438 and subsequently conquered the lower Urubamba Valley where Machu Picchu is located. Based on those records, scholars have estimated that the site was built after A.D. 1440, and perhaps as late as A.D. 1450, depending on how long it took Pachacuti to subdue the region and construct the stone palace.

The AMS technique can date bones and teeth that contain even small amounts of organic material, expanding the pool of remains suitable for scientific analysis. For this study, the researchers used it to analyze human samples from 26 individuals that were recovered from four cemeteries at Machu Picchu in 1912 during excavations. The bones and teeth used in the analysis likely belonged to retainers, or attendants, who were assigned to the royal estate, the study states. The remains show little evidence of involvement in heavy physical labor, such as construction, meaning that they likely were from the period when the site functioned as a country palace, not when it was being built, the researchers said.

The AMS testing indicates that the historical timeline is inaccurate. This is the first study based on scientific evidence to provide an estimate for the founding of Machu Picchu and the length of its occupation, giving us a clearer picture of the site's origins and history.

The finding suggests that Pachacuti, whose reign set the Inca on the path to becoming pre-Columbian America's largest and most powerful empire, gained power and began his conquests decades earlier than textual sources indicate.

The results suggest that the discussion of the development of the Inca empire based primarily on colonial records needs revision. Modern radiocarbon methods provide a better foundation than the historical records for understanding Inca chronology.

https://www.cambridge.org/core/journals/antiquity/article/new-ams-d...

https://researchnews.cc/news/8221/Study--Machu-Picchu-older-than-ex...

Organ transplant recipients significantly protected by COVID-19 vaccination

 In a Brief Communication, published July 29, 2021 in the journal Transplant Infectious Disease, a team of physician-scientists.

found that solid organ transplant recipients who were vaccinated experienced an almost 80 percent reduction in the incidence of symptomatic COVID-19 compared to unvaccinated counterparts during the same time. Persons who have received an organ transplant are considered to be at increased risk for COVID-19 and for a severe outcome because their immune systems are necessarily suppressed to ensure their transplants are successful and lasting.

These new findings offer strong evidence that getting vaccinated provides significant protection even to the immuno-suppressed people.

During the study period, there were 65 diagnosed cases of COVID-19 among the organ recipients: four among fully vaccinated individuals and 61 among the controls (two involving partially vaccinated individuals). There were no deaths among the breakthrough COVID-19 cases, but two among the 61 control cases.

it demonstrates real world clinical effectiveness of COVID-19 vaccination in a vulnerable population. Second, the effectiveness is better than expected, given that studies have found that only about half of solid organ transplant recipients develop detectable anti-spike antibodies after vaccination.

https://researchnews.cc/news/8207/Organ-transplant-recipients-signi...

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Sunscreen Chemistry and Action