Simple, solar-powered water desalination

Sun and ocean.

A completely passive solar-powered desalination system developed by researchers at MIT and in China could provide more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area. Such systems could potentially serve off-grid arid coastal areas to provide an efficient, low-cost water source.

The system uses multiple layers of flat solar evaporators and condensers, lined up in a vertical array and topped with transparent aerogel insulation. It is described in a paper appearing today in the journal Energy and Environmental Science, authored by MIT doctoral students Lenan Zhang and Lin Zhao, postdoc Zhenyuan Xu, professor of mechanical engineering and department head Evelyn Wang, and eight others at MIT and at Shanghai Jiao Tong University in China.

The key to the system's efficiency lies in the way it uses each of the multiple stages to desalinate the water. At each stage, heat released by the previous stage is harnessed instead of wasted. In this way, the team's demonstration device can achieve an overall efficiency of 385 percent in converting the energy of sunlight into the energy of water evaporation.

The device is essentially a multilayer solar still, with a set of evaporating and condensing components like those used to distill liquor. It uses flat panels to absorb heat and then transfer that heat to a layer of water so that it begins to evaporate. The vapor then condenses on the next panel. That water gets collected, while the heat from the vapor condensation gets passed to the next layer.

Whenever vapor condenses on a surface, it releases heat; in typical condenser systems, that heat is simply lost to the environment. But in this multilayer evaporator the released heat flows to the next evaporating layer, recycling the solar heat and boosting the overall efficiency.

"When you condense water, you release energy as heat," Wang says. "If you have more than one stage, you can take advantage of that heat."

Adding more layers increases the conversion efficiency for producing potable water, but each layer also adds cost and bulk to the system. The team settled on a 10-stage system for their proof-of-concept device, which was tested on an MIT building rooftop. The system delivered pure water that exceeded city drinking water standards, at a rate of 5.78 liters per square meter (about 1.52 gallons per 11 square feet) of solar collecting area. This is more than two times as much as the record amount previously produced by any such passive solar-powered desalination system, Wang says.

Theoretically, with more desalination stages and further optimization, such systems could reach overall efficiency levels as high as 700 or 800 percent, Zhang says.

Unlike some desalination systems, there is no accumulation of salt or concentrated brines to be disposed of. In a free-floating configuration, any salt that accumulates during the day would simply be carried back out at night through the wicking material and back into the seawater, according to the researchers.

Their demonstration unit was built mostly from inexpensive, readily available materials such as a commercial black solar absorber and paper towels for a capillary wick to carry the water into contact with the solar absorber. In most other attempts to make passive solar desalination systems, the solar absorber material and the wicking material have been a single component, which requires specialized and expensive materials, Wang says. "We've been able to decouple these two."

The most expensive component of the prototype is a layer of transparent aerogel used as an insulator at the top of the stack, but the team suggests other less expensive insulators could be used as an alternative. (The aerogel itself is made from dirt-cheap silica but requires specialized drying equipment for its manufacture.)

Wang emphasizes that the team's key contribution is a framework for understanding how to optimize such multistage passive systems, which they call thermally localized multistage desalination. The formulas they developed could likely be applied to a variety of materials and device architectures, allowing for further optimization of systems based on different scales of operation or local conditions and materials.

One possible configuration would be floating panels on a body of saltwater such as an impoundment pond. These could constantly and passively deliver fresh water through pipes to the shore, as long as the sun shines each day. Other systems could be designed to serve a single household, perhaps using a flat panel on a large shallow tank of seawater that is pumped or carried in. The team estimates that a system with a roughly 1-square-meter solar collecting area could meet the daily drinking water needs of one person. In production, they think a system built to serve the needs of a family might be built for around $100.

Read more at Science Daily

Bumblebees carry heavy loads in economy mode

Bumble bee hovering near thistle.

Bumblebees are the big lifters of the insect world, able to fly back to the hive with almost their own bodyweight in nectar on board. A study published Feb. 5 in Science Advances shows how they do it -- and that bees can show more flexibility in behavior than you might expect from a bumbling insect.

"They can carry 60, 70 or 80 percent of their body weight flying, which would be a huge load for us just walking around," said researcher Susan Gagliardi, a research associate in the College of Biological Sciences at the University of California, Davis. "We were curious to see how they do it and how much it costs them to carry food and supplies back to the hive."

Gagliardi and Stacey Combes, associate professor in the Department of Neurobiology, Physiology and Behavior, measured the energy expended by bumblebees flying in a specially designed chamber (an emptied snowglobe). They attached small pieces of solder wire to the bees to adjust their weight.

"We have the bees in a little chamber and we measure the carbon dioxide they produce. They are mostly burning sugar so you can tell directly how much sugar they are using as they are flying," Gagliardi said.

They also used high-speed video to examine wing beats and movements.

Bumblebees fly in a very different way to aircraft, Combes said. While air flows smoothly over an aircraft wing or rotor blade, bees move their wings at a high angle to the air generating vortices that curl round the wing. This produces much more lift than smooth airflow, but it is unstable as the vortices quickly break down. Bees are able to sustain flight by moving their wings very rapidly.

Two modes of flight

Because bumblebees fuel flight from the nectar they are carrying, they should get lighter as they fly and use less energy. To their surprise, Combes and Gagliardi found that the bees could actually use less energy per unit load when they were more heavily laden.

"They get more economical in flying the more heavily loaded they are, which doesn't make any sense in terms of energetics," Combes said.

Looking closely, the researchers found that bumblebees have two different ways to cope with increasing loads. They always increase stroke amplitude (how far the wings flap) when they are more heavily loaded, but this isn't enough to support the extra weight on its own. To make up the difference, bees can increase wingbeat frequency, which generates more lift and increases energetic cost.

But bees also have an alternative, subtly different flying mode that allows them to carry heavier loads while expending less energy than when they increase flapping frequency.

It's not yet clear exactly what this "economy mode" involves, Combes said, although it may involve a change in how the wing rotates to reverse direction between strokes. But it is something the bees can chose to do, or not.

"It turns out to be a behavioral choice they are making in terms of how they support the load," Combes said. When bees are lightly loaded or rested, they are more likely to increase wingbeat frequency. When they are more heavily loaded, they switch to the mysterious economy mode, producing enough force to support the load with only a small increase, or even a decrease, in flapping frequency.

Economy and stability

If the bees can save energy while flying, why don't they use this economy mode all the time? It's not clear, but it may be that high wingbeat frequency has performance advantages, for example in maintaining stability in turbulent air or avoiding obstacles, Combes said.

The work has prompted a shift in how Combes sees insects, she said.

"When I started in this field there was a tendency to see them as little machines, we thought they'll flap their wings one way when carrying zero load, another way when they're carrying 50 percent load and every bee will do it the same way every time," she said. "This has given us an appreciation that it's a behavior, they choose what to do. Even the same bee on a different day will pick a new way to flap its wings."

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Astronomers reveal rare double nucleus in nearby 'Cocoon Galaxy'

The so-called "Cocoon Galaxy" not only has a unique shape, it has a rare double-nucleus structure, astronomers report in a new paper.

After studying data from optical and radio telescopes based on the ground and in space, a team of astronomers determined that a galaxy known as NGC 4490 (and nicknamed the "Cocoon Galaxy" because of its shape) has "a clear double nucleus structure," according to their paper.

One nucleus can be seen in optical wavelengths. The other is hidden in dust and can only be seen in infrared and radio wavelengths.

The paper reporting the discovery is now online and has been accepted for publication in the Astrophysical Journal. First author is Allen Lawrence, who earned a master's degree in astronomy from Iowa State University in 2018 and continues to work with Iowa State astronomers.

Co-authors are Iowa State's Charles Kerton, an associate professor of physics and astronomy; and Curtis Struck, a professor of physics and astronomy; as well as East Tennessee State University's Beverly Smith, a professor of physics and astronomy.

Lawrence started the study in 2013 while taking astronomy classes at the University of Wisconsin-Madison. He had the chance to study one of two galaxy systems and picked NGC 4490, which is interacting with a smaller galaxy, NGC 4485. The system is about 20% the size of the Milky Way, located in the Northern Hemisphere and about 30 million light years from Earth.

"I saw the double nucleus about seven years ago," Lawrence said. "It had never been observed -- or nobody had ever done anything with it before."

Some astronomers may have seen one nucleus with their optical telescopes. And others may have seen the other with their radio telescopes. But he said the two groups never compared notes to observe and describe the double nucleus.

The new paper says both nuclei are similar in size, mass and luminosity. It says both are similar in mass and luminosity to the nuclei observed in other interacting galaxy pairs. And, it says the double nucleus structure could also explain why the galaxy system is surrounded by an enormous plume of hydrogen.

"The most straightforward interpretation of the observations is that NGC 4490 is itself a late-stage merger remnant" of a much-earlier collision of two galaxies, the authors wrote. A merger could drive and extend the high level of star formation necessary to create such a large hydrogen plume.

The astronomers said there are other reasons they find the study of this system interesting:

Struck, who studies colliding galaxies, said double-nucleus galaxies are very rare, especially in smaller galaxies such as this one. And, he said astronomers think a double nucleus could contribute to the buildup of super massive black holes found in the center of some galaxies.

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Simulating a universe in which Newton's laws are only partially valid

For the first time, researchers from the Universities of Bonn and Strasbourg have simulated the formation of galaxies in a universe without dark matter. To replicate this process on the computer, they have instead modified Newton's laws of gravity. The galaxies that were created in the computer calculations are similar to those we actually see today. According to the scientists, their assumptions could solve many mysteries of modern cosmology. The results are published in the Astrophysical Journal.

Cosmologists nowadays assume that matter was not distributed entirely evenly after the Big Bang. The denser places attracted more and more matter from their surroundings due to their stronger gravitational forces. Over the course of several billion years, these accumulations of gas eventually formed the galaxies we see today.

An important ingredient of this theory is the so-called dark matter. On the one hand, it is said to be responsible for the initial uneven distribution that led to the agglomeration of the gas clouds. It also explains some puzzling observations. For instance, stars in rotating galaxies often move so fast that they should actually be ejected. It appears that there is an additional source of gravity in the galaxies that prevents this -- a kind of "star putty" that cannot be seen with telescopes: dark matter.

However, there is still no direct proof of its existence. "Perhaps the gravitational forces themselves simply behave differently than previously thought," explains Prof. Dr. Pavel Kroupa from the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn and the Astronomical Institute of Charles University in Prague. This theory bears the abbreviation MOND (MOdified Newtonian Dynamics); it was discovered by the Israeli physicist Prof. Dr. Mordehai Milgrom. According to the theory, the attraction between two masses obeys Newton's laws only up to a certain point. Under very low accelerations, as is the case in galaxies, it becomes considerably stronger. This is why galaxies do not break apart as a result of their rotational speed.

Results close to reality

"In cooperation with Dr. Benoit Famaey in Strasbourg, we have now simulated for the first time whether galaxies would form in a MOND universe and if so, which ones," says Kroupa's doctoral student Nils Wittenburg. To do this he used a computer program for complex gravitational calculations which was developed in Kroupa's group. Because with MOND, the attraction of a body depends not only on its own mass, but also on whether other objects are in its vicinity.

The scientists then used this software to simulate the formation of stars and galaxies, starting from a gas cloud several hundred thousand years after the Big Bang. "In many aspects, our results are remarkably close to what we actually observe with telescopes," explains Kroupa. For instance, the distribution and velocity of the stars in the computer-generated galaxies follow the same pattern that can be seen in the night sky. "Furthermore, our simulation resulted mostly in the formation of rotating disk galaxies like the Milky Way and almost all other large galaxies we know," says the scientist. "Dark matter simulations, on the other hand, predominantly create galaxies without distinct matter disks -- a discrepancy to the observations that is difficult to explain."

Calculations based on the existence of dark matter are also very sensitive to changes in certain parameters, such as the frequency of supernovae and their effect on the distribution of matter in galaxies. In the MOND simulation, however, these factors hardly played a role.

Read more at Science Daily

Majority of US adults believe climate change is most important issue today

As the effects of climate change become more evident, more than half of U.S. adults (56%) say climate change is the most important issue facing society today, yet 4 in 10 have not made any changes in their behavior to reduce their contribution to climate change, according to a new poll by the American Psychological Association.

While 7 in 10 say they wish there were more they could do to combat climate change, 51% of U.S. adults say they don't know where to start. And as the election race heats up, 62% say they are willing to vote for a candidate because of his or her position on climate change.

The survey was conducted online from Dec. 12-16, 2019, by The Harris Poll on behalf of the American Psychological Association.

People are taking some steps to combat climate change, with 6 in 10 saying they have changed a behavior to reduce their contribution to climate change. Nearly three-quarters (72%) say they are very or somewhat motivated to make changes.

Among those who have already made behavior changes to reduce their contribution to climate change, when asked why they have not done more, 1 in 4 (26%) cite not having the resources, such as time, money or skills, to make changes. Some people are unwilling to make any changes in their behavior to reduce their contribution to climate change. When those who have not changed their behavior were asked if anything would motivate them to reduce their contribution to climate change, 29% said nothing would motivate them to do so.

Concern about climate change may be having an impact on mental health, with more than two-thirds of adults (68%) saying that they have at least a little "eco-anxiety," defined as any anxiety or worry about climate change and its effects. These effects may be disproportionately having an impact on the country's youngest adults; nearly half of those age 18-34 (47%) say the stress they feel about climate change affects their daily lives.

"The health, economic, political and environmental implications of climate change affect all of us. The tolls on our mental health are far reaching," said Arthur C. Evans Jr., PhD, APA's chief executive officer. "As climate change is created largely by human behavior, psychologists are continuing to study ways in which we can encourage people to make behavioral changes -- both large and small -- so that collectively we can help our planet."

Psychological research shows us that when people learn about and experience local climate impacts, their understanding of the effects of climate change increases. A quarter of those who have not yet made a behavior change to reduce their contribution to climate change say personally experiencing environmental impacts of climate change (e.g., natural disasters, extreme weather conditions) (25%) or seeing environmental impacts of climate change in their community (24%) would make them want to try to reduce their contribution to climate change.

The most common behavior changes people have already made or are willing to make include: reducing waste, including recycling (89%); upgrading insulation in their homes (81%); limiting utility use in their homes (79%); using renewable energy sources, such as solar panels or purchasing electricity from a renewable energy supplier (78%); consuming less in general (77%); or limiting air travel (75%).

Adults are less likely to say they have changed or are willing to change daily transportation habits (e.g., carpool, drive an electric or hybrid vehicle, use public transportation, walk or bike) (67%) or their diet (e.g., eat less red meat or switch to a vegetarian or vegan diet) (62%).

A majority (70%) also say that they have already or are willing to take action such as working with their community to reduce emissions, for example by installing bike paths, hosting farmers markets, or using community solar panels. And nearly 6 in 10 (57%) say that they have already or are willing to write or lobby elected officials about climate change action with a similar proportion (57%) saying they already have or are willing to join an organization or committee working on climate change action.

Read more at Science Daily

Why bumble bees are going extinct in time of 'climate chaos'

When you were young, were you the type of child who would scour open fields looking for bumble bees? Today, it is much harder for kids to spot them, since bumble bees are drastically declining in North America and in Europe.

A new study from the University of Ottawa found that in the course of a single human generation, the likelihood of a bumble bee population surviving in a given place has declined by an average of over 30%.

Peter Soroye, a PhD student in the Department of Biology at the University of Ottawa, Jeremy Kerr, professor at the University of Ottawa and head of the lab group Peter is in, along with Tim Newbold, research fellow at UCL (University College London), linked the alarming idea of ''climate chaos'' to extinctions, and showed that those extinctions began decades ago.

"We've known for a while that climate change is related to the growing extinction risk that animals are facing around the world," first author Peter Soroye explained. "In this paper, we offer an answer to the critical questions of how and why that is. We find that species extinctions across two continents are caused by hotter and more frequent extremes in temperatures."

"We have now entered the world's sixth mass extinction event, the biggest and most rapid global biodiversity crisis since a meteor ended the age of the dinosaurs." -- Peter Soroye

Massive decline of the most important pollinators on Earth

"Bumble bees are the best pollinators we have in wild landscapes and the most effective pollinators for crops like tomato, squash, and berries," Peter Soroye observed. "Our results show that we face a future with many less bumble bees and much less diversity, both in the outdoors and on our plates."

The researchers discovered that bumble bees are disappearing at rates "consistent with a mass extinction."

"If declines continue at this pace, many of these species could vanish forever within a few decades," Peter Soroye warned.

The technique

"We know that this crisis is entirely driven by human activities," Peter Soroye said. "So, to stop this, we needed to develop tools that tell us where and why these extinctions will occur."

The researchers looked at climate change and how it increases the frequency of really extreme events like heatwaves and droughts, creating a sort of "climate chaos" which can be dangerous for animals. Knowing that species all have different tolerances for temperature (what's too hot for some might not be for others), they developed a new measurement of temperature.

"We have created a new way to predict local extinctions that tells us, for each species individually, whether climate change is creating temperatures that exceed what the bumble bees can handle," Dr. Tim Newbold explained.

Using data on 66 different bumble bee species across North America and Europe that have been collected over a 115-year period (1900-2015) to test their hypothesis and new technique, the researchers were able to see how bumble bee populations have changed by comparing where bees are now to where they used to be historically.

"We found that populations were disappearing in areas where the temperatures had gotten hotter," Peter Soroye said. "Using our new measurement of climate change, we were able to predict changes both for individual species and for whole communities of bumble bees with a surprisingly high accuracy."

A new horizon of research

This study doesn't end here. In fact, it opens the doors to new research horizons to track extinction levels for other species like reptiles, birds and mammals.

"Perhaps the most exciting element is that we developed a method to predict extinction risk that works very well for bumble bees and could in theory be applied universally to other organisms," Peter Soroye indicated. "With a predictive tool like this, we hope to identify areas where conservation actions would be critical to stopping declines."

"Predicting why bumble bees and other species are going extinct in a time of rapid, human-caused climate change could help us prevent extinction in the 21st century." -- Dr. Jeremy Kerr

There is still time to act

"This work also holds out hope by implying ways that we might take the sting out of climate change for these and other organisms by maintaining habitats that offer shelter, like trees, shrubs, or slopes, that could let bumble bees get out of the heat," Dr. Kerr said. "Ultimately, we must address climate change itself and every action we take to reduce emissions will help. The sooner the better. It is in all our interests to do so, as well as in the interests of the species with whom we share the world."

Read more at Science Daily

One small grain of moon dust, one giant leap for lunar studies

Moon surface

Back in 1972, NASA sent their last team of astronauts to the Moon in the Apollo 17 mission. These astronauts brought some of the Moon back to Earth so scientists could continue to study lunar soil in their labs. Since we haven't returned to the Moon in almost 50 years, every lunar sample is precious. We need to make them count for researchers now and in the future. In a new study in Meteoritics & Planetary Science, scientists found a new way to analyze the chemistry of the Moon's soil using a single grain of dust. Their technique can help us learn more about conditions on the surface of the Moon and formation of precious resources like water and helium there.

"We're analyzing rocks from space, atom by atom," says Jennika Greer, the paper's first author and a PhD student at the Field Museum and University of Chicago. " It's the first time a lunar sample has been studied like this. We're using a technique many geologists haven't even heard of.

"We can apply this technique to samples no one has studied," Philipp Heck, a curator at the Field Museum, associate professor at the University of Chicago, and co-author of the paper, adds. "You're almost guaranteed to find something new or unexpected. This technique has such high sensitivity and resolution, you find things you wouldn't find otherwise and only use up a small bit of the sample."

The technique is called atom probe tomography (APT), and it's normally used by materials scientists working to improve industrial processes like making steel and nanowires. But its ability to analyze tiny amounts of materials makes it a good candidate for studying lunar samples. The Apollo 17 sample contains 111 kilograms (245 pounds) of lunar rocks and soil -- the grand scheme of things, not a whole lot, so researchers have to use it wisely. Greer's analysis only required one single grain of soil, about as wide as a human hair. In that tiny grain, she identified products of space weathering, pure iron, water and helium, that formed through the interactions of the lunar soil with the space environment. Extracting these precious resources from lunar soil could help future astronauts sustain their activities on the Moon.

To study the tiny grain, Greer used a focused beam of charged atoms to carve a tiny, super-sharp tip into its surface. This tip was only a few hundred atoms wide -- for comparison, a sheet of paper is hundreds of thousands of atoms thick. "We can use the expression nanocarpentry," says Philipp Heck. "Like a carpenter shapes wood, we do it at the nanoscale to minerals."

Once the sample was inside the atom probe at Northwestern University, Greer zapped it with a laser to knock atoms off one by one. As the atoms flew off the sample, they struck a detector plate. Heavier elements, like iron, take longer to reach the detector than lighter elements, like hydrogen. By measuring the time between the laser firing and the atom striking the detector, the instrument is able to determine the type of atom at that position and its charge. Finally, Greer reconstructed the data in three dimensions, using a color-coded point for each atom and molecule to make a nanoscale 3D map of the Moon dust.

It's the first time scientists can see both the type of atoms and their exact location in a speck of lunar soil. While APT is a well-known technique in material science, nobody had ever tried using it for lunar samples before. Greer and Heck encourage other cosmochemists to try it out. "It's great for comprehensively characterizing small volumes of precious samples," Greer says. "We have these really exciting missions like Hayabusa2 and OSIRIS-REx returning to Earth soon -- uncrewed spacecrafts collecting tiny pieces of asteroids. This is a technique that should definitely be applied to what they bring back because it uses so little material but provides so much information."

Studying soil from the moon's surface gives scientists insight into an important force within our Solar System: space weathering. Space is a harsh environment, with tiny meteorites, streams of particles coming off the Sun, and radiation in the form of solar and cosmic rays. While Earth's atmosphere protects us from space weathering, other bodies like the Moon and asteroids don't have atmospheres. As a result, the soil on the Moon's surface has undergone changes caused by space weathering, making it fundamentally different from the rock that the rest of the Moon is composed of. It's kind of like a chocolate-dipped ice cream cone: the outer surface doesn't match what's inside. With APT, scientists can look for differences between space weathered surfaces and unexposed moon dirt in a way that no other method can. By understanding the kinds of processes that make these differences happen, they can more accurately predict what's just under the surface of moons and asteroids that are too far away to bring to Earth.

Because Greer's study used a nanosized tip, her original grain of lunar dust is still available for future experiments. This means new generations of scientists can make new discoveries and predictions from the same precious sample. "Fifty years ago, no one anticipated that someone would ever analyze a sample with this technique, and only using a tiny bit of one grain," Heck states. "Thousands of such grains could be on the glove of an astronaut, and it would be sufficient material for a big study."

Greer and Heck emphasize the need for missions where astronauts bring back physical samples because of the variety of terrains in outer space. "If you only analyze space weathering from the one place on the Moon, it's like only analyzing weathering on Earth in one mountain range," Greer says. We need to go to other places and objects to understand space weathering in the same way we need to check out different places on Earth like the sand in deserts and outcrops in mountain ranges on Earth."

We don't yet know what surprises we might find from space weathering. "It's important to understand these materials in the lab so we understand what we're seeing when we look through a telescope," Greer says. "Because of something like this, we understand what the environment is like on the Moon. It goes way beyond what astronauts are able to tell us as they walk on the Moon. This little grain preserves millions of years of history.

Read more at Science Daily

Molecular 'switch' reverses chronic inflammation and aging

Hourglass, aging concept

Chronic inflammation, which results when old age, stress or environmental toxins keep the body's immune system in overdrive, can contribute to a variety of devastating diseases, from Alzheimer's and Parkinson's to diabetes and cancer.

Now, scientists at the University of California, Berkeley, have identified a molecular "switch" that controls the immune machinery responsible for chronic inflammation in the body. The finding, which appears online Feb. 6 in the journal Cell Metabolism, could lead to new ways to halt or even reverse many of these age-related conditions.

"My lab is very interested in understanding the reversibility of aging," said senior author Danica Chen, associate professor of metabolic biology, nutritional sciences and toxicology at UC Berkeley. "In the past, we showed that aged stem cells can be rejuvenated. Now, we are asking: to what extent can aging be reversed? And we are doing that by looking at physiological conditions, like inflammation and insulin resistance, that have been associated with aging-related degeneration and diseases."

In the study, Chen and her team show that a bulky collection of immune proteins called the NLRP3 inflammasome -- responsible for sensing potential threats to the body and launching an inflammation response -- can be essentially switched off by removing a small bit of molecular matter in a process called deacetylation.

Overactivation of the NLRP3 inflammasome has been linked to a variety of chronic conditions, including multiple sclerosis, cancer, diabetes and dementia. Chen's results suggest that drugs targeted toward deacetylating, or switching off, this NLRP3 inflammasome might help prevent or treat these conditions and possibly age-related degeneration in general.

"This acetylation can serve as a switch," Chen said. "So, when it is acetylated, this inflammasome is on. When it is deacetylated, the inflammasome is off."

By studying mice and immune cells called macrophages, the team found that a protein called SIRT2 is responsible for deacetylating the NLRP3 inflammasome. Mice that were bred with a genetic mutation that prevented them from producing SIRT2 showed more signs of inflammation at the ripe old age of two than their normal counterparts. These mice also exhibited higher insulin resistance, a condition associated with type 2 diabetes and metabolic syndrome.

The team also studied older mice whose immune systems had been destroyed with radiation and then reconstituted with blood stem cells that produced either the deacetylated or the acetylated version of the NLRP3 inflammasome. Those who were given the deacetylated, or "off," version of the inflammasome had improved insulin resistance after six weeks, indicating that switching off this immune machinery might actually reverse the course of metabolic disease.

"I think this finding has very important implications in treating major human chronic diseases," Chen said. "It's also a timely question to ask, because in the past year, many promising Alzheimer's disease trials ended in failure. One possible explanation is that treatment starts too late, and it has gone to the point of no return. So, I think it's more urgent than ever to understand the reversibility of aging-related conditions and use that knowledge to aid a drug development for aging-related diseases."

Read more at Science Daily

Breathing may change your mind about free will

Have you ever gone ahead and eaten that piece of chocolate, despite yourself?

Do you inadvertently make decisions because you are hungry or cold? In other words, does the brain's processing of internal bodily signals interfere with your ability to act freely?

This line of thinking is at the heart of research that questions our ability to act on thoughts of free will. We already know that inner body signals, like the heartbeat, affect our mental states, can be used to reduce the perception of pain and are of fundamental importance for bodily self-consciousness.

Thanks to a new discovery, it turns out that these inner body signals do indeed affect acts of volition.

Scientists at EPFL in Switzerland have shown that you are more likely to initiate a voluntary decision as you exhale. Published in today's issue of Nature Communications, these findings propose a new angle on an almost 60-year-old neuroscientific debate about free will and the involvement of the human brain.

"We show that voluntary action is indeed linked to your body's inner state, especially with breathing and expiration but not with some other bodily signals, such as the heartbeat," explains Olaf Blanke, EPFL's Foundation Bertarelli Chair in Cognitive Neuroprosthetics and senior author.

At the center of these results is the readiness potential (RP), a signal of brain activity observed in the human cortex that appears not only before voluntary muscle movement, but also before one becomes aware of the intention to move. The RP is the signature of voluntary action since it consistently appears in brain activity measurements right before acts of free will (like being aware that one wants to reach for the chocolate).

Interpretations of the RP have been debated for decades. Some interpret the RP to show that free will is an illusion, since the RP precedes the conscious experience of free will. It seems to show that the brain commits to a decision (chocolate) before we are even consciously aware of having made that decision.

More recently, it was suggested that the RP could be an artefact of measurement, potentially putting free will back into our command.

But if we take on the view that our conscious decisions arise from a cascade of firing neurons, then the origin of the RP may actually provide insight into the mechanisms that lead to voluntary action and free will. The way the brain's neurons work together to come to a decision is still poorly understood. Our conscious experience of free will, our ability to make decisions freely, may then be intricately wired to the rest of our body.

The EPFL results suggest that the origin of the RP is linked to breathing, providing a new perspective on experiences of free will: the regular cycle of breathing is part of the mechanism that leads to conscious decision-making and acts of free will. Moreover, we are more likely to initiate voluntary movements as we exhale. (Did you reach for that piece of chocolate during an exhale?)

These findings suggest that the breathing pattern may be used to predict 'when' people begin voluntary action. Your breathing patterns could also be used to predict consumer behavior, like when you click on that button. Medical devices that use brain-computer interfaces could be tuned and improved according to breathing. The breathing-action coupling could be used in research and diagnostic tools for patients with deficits in voluntary action control, like obsessive compulsive disorders, Parkinson disease, and Tourette syndromes. Blanke and Hyeong-Dong Park, first author of this research, have filed a patent based on these findings.

Free will hijacked by interoceptive signals?

More generally, the EPFL findings suggest that acts of free will are affected by signals from other systems of the body. Succumbing to that urge to eat chocolate may depend more on your body's internal signals than you may realize!

Blanke elaborates, "That voluntary action, an internally or self-generated action, is coupled with an interoceptive signal, breathing, may be just one example of how acts of free will are hostage to a host of inner body states and the brain's processing of these internal signals. Interestingly, such signals have also been shown to be of relevance for self-consciousness."

You may be tempted to blame acts of chocolate binging on interoceptive electrical signals hijacking your free will. The gut-mind connection is an active field of research and interoceptive messages sent to the brain certainly impact food cravings. For now, this latest EPFL research only improves predictions of when you will indulge in that craving, and not what you actually crave.

Acts of free will and inner states of the body

The prevailing view in neuroscience is that consciousness is an emergent phenomenon of the brain. Firing of the brain's neurons leads to consciousness and the feeling of free will or voluntary action. By belonging to the physical universe, the brain's electrical activity within the constraints of anatomy, is subject to the laws of physics. In this sense, brain signals encoding the body, lungs and heart might naturally affect the brain's cognitive states too and therefore influence acts of free will.

To test whether the RP depends on the body's inner state and the brain's representation thereof, Blanke and colleagues asked 52 subjects to press a button at will at Campus Biotech in Geneva. EEGs monitored brain activity, a belt around the chest measured breathing activity and cardiac activity was recorded.

The scientists found that the RP and voluntary action (pressing the button) is linked to the body's inner state -- the regular breathing cycle -- but not to the heartbeat. Participants initiated voluntary movements more frequently during an exhale than an inhale and were completely unaware of this breathing-action coupling. The RP was also modulated depending on the breathing cycle.

EPFL scientist and first author of the study Hyeong-Dong Park explains, "The RP no longer corresponds only to cortical activity 'unconsciously preparing' voluntary action. The RP, at least partly, reflects respiration-related cortical processing that is coupled to voluntary action. More generally, it further suggests that higher-level motor control, such as voluntary action, is shaped or affected by the involuntary and cyclic motor act of our internal body organs, in particular the lungs. Still the precise neural activity that controls breathing remains to be mapped."

The readiness potential and interpretations

Philosophers, psychologists, and more recently neuroscientists have long debated our ability to act freely. The meaning of the readiness potential (RP) has been questioned ever since its discovery by neuroscientists Hans Helmut Kornhuber and Lüder Deecke in 1965, and later regarding its relation to free will in neuroscientist Benjamin Libet's experiments.

The entire brain consists of approximately 100 billion neurons, and each individual neuron transmits electrical signals as the brain works. Electrodes placed on the head can measure the collective electrical activity of the brain's neurons, seen as wavy lines called an electroencephalogram (EEG).

In 1965, neuroscientists Hans Helmut Kornhuber and Lüder Deecke conducted a seminal experiment to test voluntary action and discovered a recurring pattern of brain activity. They placed EEG electrodes on top of the subject's head, and asked the subject to press a button at will. Kornhuber and Deecke discovered that the EEG consistently exhibited a rising slope of wavy lines, the readiness potential, 1 second or more before voluntary movement.

In the early 1980s, neuroscientist Benjamin Libet further tested the relationship between the RP and conscious awareness or intention of voluntary action. His highly influential results showed that approximately 200ms before his subjects pressed the button, they were aware of an urge or the intention to act, something Libet referred to as the W time, and yet the RP consistently preceded W time.

Libet suggested that these findings showed that even before we make a conscious decision of voluntary action, the brain was already unconsciously activated and involved in planning the action.

Some have interpreted the relation between the RP and W time as an indication that human free will might be an illusion. The RP is viewed as the brain committing to a decision (to press the button) before the subject is even aware of having made that decision. If commitment to a decision is being made before we are even aware of it, then what mechanism is making the decision for us?

For the neuroscientist who considers consciousness to arise from brain activity (versus brain activity arising from consciousness), Libet's results may not surprising, since the conscious experience of free will is viewed as an emergent phenomenon of brain activity.

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Study takes a stand against prolonged sitting

In many workplaces, standing desks and walking meetings are addressing the health dangers of sitting too long each day, but for universities, the natural question is how to make such adjustments for classrooms.

The question appealed to emerita dance professor Angelia Leung from the UCLA Department of World Arts & Cultures/Dance. Sitting too long was never an issue for Leung's students. But for most college students, desk time is more common than dance time. In an unusual collaboration between the arts and sciences, Leung partnered with Burt Cowgill, an assistant adjunct professor with the UCLA Fielding School of Public Health, to find ways to help students stand up.

The team's research, published in the Journal of American College Health on Feb. 6, hit upon solutions that students and faculty can agree on. However, all the solutions, the researchers said, would work best if joined with an effort to raise awareness about the health risks of extended sitting, aimed at shifting cultural expectations and norms about classroom etiquette.

Studies have linked prolonged sitting with health concerns such as heart disease, cancer, depression, diabetes and obesity. Research shows that breaking up long periods of sitting with movement at least once an hour reduces those risks, while regular exercise at other times of day does not. Despite those risks, the UCLA research found that more than half of students interviewed considered it socially unacceptable to stand up and stretch in the middle of class, and nearly two-thirds felt the same about doing so during smaller discussion sections.

"A cultural change has to take place -- that it's OK to take a stretch break, to stand up during a lecture, to fidget when needed -- it's 'good' for health's sake," Leung said. "My students have an advantage because dance classes naturally involve movement, but we can extend these benefits to any class on campus with something as simple as short stretching breaks -- no dancing required."

Some of the recommendations are simple: Take hourly breaks to stand and stretch during long classes; include more small-group activities that require moving to switch desks; and create more open classrooms with space to walk without squeezing past fellow students and room to install standing desk areas.

To overcome social stigma, the researchers emphasized that professors and instructors will have to take the lead in offering group breaks at specific times rather than suggesting students can get up any time they wish. They also recommended that professors encourage students to get up and move during their breaks; and suggested that university administrators establish policies that call for building more open classrooms and adding features such as adjustable desks.

The research was funded by the Semel Healthy Campus Initiative Center at UCLA, a campuswide effort to make the healthy choice the easy choice, and to promote wellness through education and research. For the study, moderators conducted eight focus-group interviews and guided discussions with 66 UCLA students, roughly half undergraduates and half graduate students. The researchers also interviewed eight faculty members. The researchers looked at how much students and faculty knew about the health risks of sitting, investigated whether the participants could avoid prolonged sitting in class, and gathered ideas for feasible solutions.

"We need to change the way we teach so that we can offer more standing breaks, create opportunities for in-class movement, and even change the built environment so that there's more room for moving around," Cowgill said.

But even though the study found that students and faculty were broadly supportive of making changes, Cowgill said he doubts people will, ahem, stand up against the status quo if there isn't also an effort to raise awareness about the health risks. Social norms and the physical classroom environment are barriers, but awareness is the biggest obstacle.

Cowgill said he was surprised to learn that many of the participants were not aware of the health problems that prolonged sitting can cause, even for people who are otherwise active. "Many people thought they would be fine if they also squeezed in a 30-minute jog, and that's just not what research shows us."

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