Rats bop to the beat

Rats can move their heads in time to music, demonstrating innate beat synchronization in animals for the first time

Peer-Reviewed Publication

UNIVERSITY OF TOKYO

 

VIDEO: ALTHOUGH THE MAIN STUDY FOCUSED ON RESPONSES TO K. 448 BY MOZART, FOUR OTHER MUSICAL PIECES WERE ALSO PLAYED TO THE HUMAN AND ANIMAL PARTICIPANTS: BORN THIS WAY BY LADY GAGA, ANOTHER ONE BITES THE DUST BY QUEEN, BEAT IT BY MICHAEL JACKSON AND SUGAR BY MAROON 5. view more 

CREDIT: 2022 ITO ET AL.

Accurately moving to a musical beat was thought to be a skill innately unique to humans. However, new research now shows that rats also have this ability. The optimal tempo for nodding along was found to depend on the time constant in the brain (the speed at which our brains can respond to something), which is similar across all species. This means that the ability of our auditory and motor systems to interact and move to music may be more widespread among species than previously thought. This new discovery offers not only further insight into the animal mind, but also into the origins of our own music and dance. 

Can you move to the beat, or do you have two left feet? Apparently, how well we can time our movement to music depends somewhat on our innate genetic ability, and this skill was previously thought to be a uniquely human trait. While animals also react to hearing noise, or might make rhythmic sounds, or be trained to respond to music, this isn’t the same as the complex neural and motor processes that work together to enable us to naturally recognize the beat in a song, respond to it or even predict it. This is referred to as beat synchronicity.

Only relatively recently, research studies (and home videos) have shown that some animals seem to share our urge to move to the groove. A new paper by a team at the University of Tokyo provides evidence that rats are one of them. “Rats displayed innate — that is, without any training or prior exposure to music — beat synchronization most distinctly within 120-140 bpm (beats per minute), to which humans also exhibit the clearest beat synchronization,” explained Associate Professor Hirokazu Takahashi from the Graduate School of Information Science and Technology. “The auditory cortex, the region of our brain that processes sound, was also tuned to 120-140 bpm, which we were able to explain using our mathematical model of brain adaptation.”

But why play music to rats in the first place? “Music exerts a strong appeal to the brain and has profound effects on emotion and cognition. To utilize music effectively, we need to reveal the neural mechanism underlying this empirical fact,” said Takahashi. “I am also a specialist of electrophysiology, which is concerned with electrical activity in the brain, and have been studying the auditory cortex of rats for many years.”

The team had two alternate hypotheses: The first was that the optimal music tempo for beat synchronicity would be determined by the time constant of the body. This is different between species and much faster for small animals compared to humans (think of how quickly a rat can scuttle). The second was that the optimal tempo would instead be determined by the time constant of the brain, which is surprisingly similar across species. “After conducting our research with 20 human participants and 10 rats, our results suggest that the optimal tempo for beat synchronization depends on the time constant in the brain,” said Takahashi. “This demonstrates that the animal brain can be useful in elucidating the perceptual mechanisms of music.”

The rats were fitted with wireless, miniature accelerometers, which could measure the slightest head movements. Human participants also wore accelerometers on headphones. They were then played one-minute excerpts from Mozart’s Sonata for Two Pianos in D Major, K. 448, at four different tempos: Seventy-five percent, 100%, 200% and 400% of the original speed. The original tempo is 132 bpm and results showed that the rats’ beat synchronicity was clearest within the 120-140 bpm range. The team also found that both rats and humans jerked their heads to the beat in a similar rhythm, and that the level of head jerking decreased the more that the music was sped up.

“To the best of our knowledge, this is the first report on innate beat synchronization in animals that was not achieved through training or musical exposure,” said Takahashi. “We also hypothesized that short-term adaptation in the brain was involved in beat tuning in the auditory cortex. We were able to explain this by fitting our neural activity data to a mathematical model of the adaptation. Furthermore, our adaptation model showed that in response to random click sequences, the highest beat prediction performance occurred when the mean interstimulus interval (the time between the end of one stimulus and the start of another) was around 200 milliseconds (one-thousandth of a second). This matched the statistics of internote intervals in classical music, suggesting that the adaptation property in the brain underlies the perception and creation of music.”

As well as being a fascinating insight into the animal mind and the development of our own beat synchronicity, the researchers also see it as an insight into the creation of music itself. “Next, I would like to reveal how other musical properties such as melody and harmony relate to the dynamics of the brain. I am also interested in how, why and what mechanisms of the brain create human cultural fields such as fine art, music, science, technology and religion,” said Takahashi. “I believe that this question is the key to understand how the brain works and develop the next-generation AI (artificial intelligence). Also, as an engineer, I am interested in the use of music for a happy life.”

####

Paper Title:

Yoshiki Ito, Tomoyo Isoguchi Shiramatsu, Naoki Ishida, Karin Oshima, Kaho Magami, Hirokazu Takahashi. Spontaneous beat synchronization in rats: Neural dynamics and motor entrainment. Science Advances 8, eabo7019 (2022). DOI: 10.1126/sciadv.abo7019

Funding: 

This work was supported in part by JSPS KAKENHI (20H04252, 21H05807) and JST Moonshot R & D program (JPMJMS2296).

Useful Links:

Graduate School of Information Science and Technology: https://www.i.u-tokyo.ac.jp/index_e.shtml

Hirokazu Takahashi Lab: http://www.ne.t.u-tokyo.ac.jp/index-e.html  

Research contact:
Associate Professor Hirokazu Takahashi
Department of Mechano-Informatics,

Graduate School of Information Science and Technology,

The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan

Email: takahashi@i.u-tokyo.ac.jp

Press contact:
Mrs. Nicola Burghall
Public Relations Group, The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
press-releases.adm@gs.mail.u-tokyo.ac.jp

About the University of Tokyo
The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on Twitter at @UTokyo_News_en.

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JOURNAL

Science Advances

DOI

10.1126/sciadv.abo7019 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Spontaneous beat synchronization in rats: Neural dynamics and motor entrainment

ARTICLE PUBLICATION DATE

11-Nov-2022

Caltech Hall is getting stiffer, according to decades of data

Peer-Reviewed Publication

SEISMOLOGICAL SOCIETY OF AMERICA

 

IMAGE: CALTECH HALL view more 

CREDIT: ETHAN WILLIAMS

Caltech Hall, a 55-year-old nine-story reinforced concrete building on the Caltech campus, has been getting structurally stiffer over the past 20 years, according to a new report published in The Seismic Record.

Previous work by seismologists and engineers had documented the building softening—that is, decreasing in stiffness—from its construction in 1967 through 2002. This trend has reversed, and today the building is back to the state it was in 1986.

This unexpected conclusion was discovered by analyzing seismic data recorded continuously since 2001 on the building’s ninth floor.

Seismic data can be used to calculate the natural frequencies of a building, a measure of its vibration in response to forcing from earthquakes and strong winds. The natural frequencies are a proxy for structural stiffness; generally, the lower the frequency, the more “flexible” the building is during an earthquake.

Caltech Ph.D. student Ethan Williams and colleagues show that for Caltech Hall (formerly known as Millikan Library), the natural frequencies have increased gradually by about 5% in the east-west direction and 2% in the north-south direction over the past 20 years. These frequencies have varied by as much as 9.7% over scales from seconds to decades, they found, implying up to 20% variation in the building’s stiffness between earthquakes.

“Engineers generally assume that buildings are either stable or degrade over their lifetime,” said Williams. “There’s no expectation, or really any understood mechanism, for how a concrete building should be getting stiffer.”

In addition to the 20-year increasing trend, researchers found that the building’s natural frequencies varied depending on season and rainfall, as well as non-structural renovations such as removing library shelving on some floors and replacing it with plastic cubicles.

Such large variability poses a significant challenge for seismic structural health monitoring, according to Williams. “Most instrumented buildings have triggered seismometers, meaning that we only get to measure a building’s natural frequencies when there’s an earthquake,” he said. “If the stiffness can vary by 20% between earthquakes, then detecting earthquake damage just by looking for changes in stiffness may be unreliable.”

The researchers also found substantial short-term changes in the natural frequencies, after analyzing data collected during earthquakes and forced vibrations. Williams and colleagues documented rapid decreases in frequencies (building softening) at the onset of shaking like that from an earthquake, followed by a slower recovery over minutes. The stronger the shaking, the softer the building appeared.

It's interesting that the building is getting stiffer, Williams said, “but the short-term dynamic elasticity is at least as important for engineering practice.” As an example, Williams points to probabilistic seismic hazard analysis: “Ground motions used in structural design are often expressed in terms of spectral acceleration, which bakes in the assumption of linear, time-invariant elasticity. If a building’s natural frequencies are continuously changing over the course of an earthquake, then spectral acceleration isn’t going to accurately represent the peak motions for a given event.”

As for the cause of Caltech Hall’s wandering natural frequencies, Williams and colleagues offer a few suggestions, but they stress that these are just speculation. For instance, groundwater that migrates through cracks in the foundation could deposit calcite that heals those cracks, increasing the building’s stiffness over years to decades. During strong shaking, pre-existing fractures in the concrete could open up or soil beneath the foundation could shift, causing the temporary softening.

Better explanations may come as continuous seismic data is recorded in more buildings, according to Williams. “There are so few buildings with continuous instrumentation that there’s a real question, is Caltech Hall just special and interesting, or are all reinforced concrete buildings so complicated and dynamic?” he said.

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JOURNAL

The Seismic Record

DOI

10.1785/0320220032 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Variability in the Natural Frequencies of a Nine‐Story Concrete Building from Seconds to Decades

ARTICLE PUBLICATION DATE

11-Nov-2022

Researchers cook up a new way to remove microplastics from water

Peer-Reviewed Publication

PRINCETON UNIVERSITY, ENGINEERING SCHOOL

 

IMAGE: THE STRUCTURE OF THE AEROGEL IS FORMED BY GRAPHENE SHEETS STRETCHED ACROSS CARBON FIBER NETWORKS. view more 

CREDIT: SHAHARYAR WANI

Researchers at Princeton Engineering have found a way to turn your breakfast food into a new material that can cheaply remove salt and microplastics from seawater.

The researchers used egg whites to create an aerogel, a lightweight and porous material that can be used in many types of applications, including water filtration, energy storage, and sound and thermal insulation. Craig Arnold, the Susan Dod Brown Professor of Mechanical and Aerospace Engineering and vice dean of innovation at Princeton, works with his lab to create new materials, including aerogels, for engineering applications.

One day, sitting in a faculty meeting, he had an idea.

“I was sitting there, staring at the bread in my sandwich,” said Arnold. “And I thought to myself, this is exactly the kind of structure that we need.” So he asked his lab group to make different bread recipes mixed with carbon to see if they could recreate the aerogel structure he was looking for. None of them worked quite right initially, so the team kept eliminating ingredients as they tested, until eventually only egg whites remained.

“We started with a more complex system,” Arnold said, “and we just kept reducing, reducing, reducing, until we got down to the core of what it was. It was the proteins in the egg whites that were leading to the structures that we needed.”

Egg whites are a complex system of almost pure protein that — when freeze-dried and heated to 900 degrees Celsius in an environment without oxygen — create a structure of interconnected strands of carbon fibers and sheets of graphene. In a paper published Aug. 24 in Materials Today, Arnold and his coauthors showed that the resulting material can remove salt and microplastics from seawater with 98% and 99% efficiency, respectively.

“The egg whites even worked if they were fried on the stove first, or whipped,” said Sehmus Ozden, first author on the paper. Ozden is a former postdoctoral research associate at the Princeton Center for Complex Materials and now a scientist at Aramco Research Center. While regular store-bought egg whites were used in initial tests, Ozden said, other similar commercially available proteins produced the same results.

“Eggs are cool because we can all connect to them and they are easy to get, but you want to be careful about competing against the food cycle,” said Arnold. Because other proteins also worked, the material can potentially be produced in large quantities relatively cheaply and without impacting the food supply. One next step for the researchers, Ozden noted, is refining the fabrication process so it can be used in water purification on a larger scale.

If this challenge can be solved, the material has significant benefits because it is inexpensive to produce, energy-efficient to use and highly effective. “Activated carbon is one of the cheapest materials used for water purification. We compared our results with activated carbon, and it’s much better,” said Ozden. Compared with reverse osmosis, which requires significant energy input and excess water for operation, this filtration process requires only gravity to operate and wastes no water.

While Arnold sees water purity as a “major grand challenge,” that is not the only potential application for this material. He is also exploring other uses related to energy storage and insulation.

The research included contributions from the departments of chemical and biological engineering and geosciences at Princeton and elsewhere. “It’s one thing to make something in the lab,” said Arnold, “and it’s another thing to understand why and how.” Collaborators who helped answer the why and how questions included professors Rodney Priestley and A. James Link from chemical and biological engineering, who helped identify the transformation mechanism of the egg white proteins at the molecular level. Princeton colleagues in geosciences assisted with measurements of water filtration.

Susanna Monti of the Institute for Chemistry of Organometallic Compounds and Valentina Tozzi from Instituto Nanoscienze and NEST-Scuola Normale Superiore created the theoretical simulations that revealed the transformation of egg white proteins into the aerogel.

The article, “Egg protein derived ultralightweight hybrid monolithic aerogel for water purification,” was published in the journal Materials Today. Besides Arnold, Monti, Ozden, Priestley, Link and Tozzi, authors include Nikita Dutta, a former graduate student in mechanical and aerospace engineering who is now at the National Renewable Energy Laboratory; Stefania Gill, John Higgins and Nick Caggiano of Princeton University; and Nicola Pugno of the University of Trento and Queen Mary University of London. Support was provided in part by the Princeton Center for Complex Materials and the U.S. National Science Foundation.

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JOURNAL

Materials Today

DOI

10.1016/j.mattod.2022.08.001 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Egg protein derived ultralightweight hybrid monolithic aerogel for water purification

Amid food and climate crises, investing in sustainable food cold chains crucial: UN

More than 3 billion people can’t afford a healthy diet; Lack of effective refrigeration directly results in the loss of 526 million tonnes of food production - 12% of global total; Developing countries could save 144 million tons of food annually

Reports and Proceedings

UNITED NATIONS ENVIRONMENT PROGRAMME

 

IMAGE: THE UN REPORT ‘SUSTAINABLE FOOD COLD CHAINS: OPPORTUNITIES, CHALLENGES AND THE WAY FORWARD’ EMPHASIZES THE NEED FOR ROBUST, SUSTAINABLE COLD CHAINS TO MAINTAIN THE QUALITY, NUTRITIONAL VALUE AND SAFETY OF FOOD, AND TO REDUCE LOSSES, OFFERING CASE STUDIES AND SOLUTIONS TO THE CHALLENGE. view more 

CREDIT: UNEP/FAO

As food insecurity and global warming rise, governments, international development partners and industry should invest in sustainable food cold chains to decrease hunger, provide livelihoods to communities, and adapt to climate change, the UN said today.

Launched today at the 27th Climate Change Conference (COP 27), the Sustainable Food Cold Chains report, from the UN Environment Programme (UNEP) and the Food and Agriculture Organization of the United Nations (FAO), finds that food cold chains are critical to meeting the challenge of feeding an additional two billion people by 2050 and harnessing rural communities’ resilience, while avoiding increased greenhouse gas emissions.

The report (at http://bit.ly/3A3dP8z) was developed in the framework of the UNEP-led Cool Coalition in partnership with FAO, the Ozone Secretariat, UNEP OzonAction Programme, and the Climate and Clean Air Coalition. 

“At a time when the international community must act to address the climate and food crises, sustainable food cold chains can make a massive difference,” said Inger Andersen, Executive Director of UNEP. “They allow us to reduce food loss, improve food security, slow greenhouse gas emissions, create jobs, reduce poverty and build resilience – all in one fell swoop.”

Food insecurity on the rise

The number of people affected by hunger in the world rose to 828 million in 2021, a year-on-year rise of 46 million. 

Almost 3.1 billion people could not afford a healthy diet in 2020, up 112 million from 2019, as the economic impacts of the Covid pandemic drove up inflation. This year, meanwhile, the conflict in Ukraine has raised the prices of basic grains threatening food security.

All of this comes while an estimated 14% of all food produced for human consumption is lost before it reaches the consumer. The lack of an effective cold chain to maintain the quality, nutritional value and safety of food is one of the major contributors (12% of total loss). 

According to the report, developing countries could save 144 million tonnes of food annually if they reached the same level of food cold chain infrastructure as developed countries. 

As post-harvest food loss reduces the income of 470 million small-scale farmers by 15%, mainly in developing countries investing in sustainable food cold chains would help lift these farm families out of poverty. 

Climate impact

The food cold chain has serious implications for climate change and the environment. Emissions from food loss and waste due to lack of refrigeration totalled an estimated 1 gigatonne of carbon dioxide (CO2) equivalent in 2017 – about 2% of total global greenhouse gas emissions.

In particular, it contributes to emissions of methane, a potent but short-lived climate pollutant. Taking action now would contribute to reducing atmospheric concentrations of methane this   decade.   

Overall, the food cold chain is responsible for around 4% of total global greenhouse gas emissions – when emissions from cold chain technologies and food loss caused by lack of refrigeration are included.

Lost food also damages the natural world by driving unnecessary conversion of land for agricultural purposes and use of resources such as water, fossil fuels and energy.

Reducing food loss and waste could make a positive impact on climate change, but only if new cooling-related infrastructure is designed to use gases with low global warming potential, be energy efficient and run on renewable energy.

The adoption of the Kigali Amendment to the Montreal Protocol and the Rome Declaration on “the contribution of the Montreal Protocol to sustainable cold chain development for food waste reduction” provide a unique opportunity to accelerate the deployment of sustainable food cold chains.

Progress being made

Projects around the world show that sustainable food cold chains are already making a difference. In India, a food cold chain pilot project reduced losses of kiwi fruit by 76% while reducing emissions through the expansion of use of refrigerated transport. 

In Nigeria, a project to install 54 operational ColdHubs prevented the spoilage of 42,024 tonnes of food and increased the household income of 5,240 small-scale farmers, retailers and wholesalers by 50%.

But these projects, among many other illustrative case studies in the new report, are still the exception rather than the norm.

Recommendations for decision makers

To expand sustainable food cold chains globally, the report makes a series of recommendations for governments and stakeholders, including:

• Take a holistic systems approach to food cold chain provision, recognizing that the provision of cooling technologies alone is not enough.
• Quantify and benchmark the energy use and greenhouse gas emissions in existing food cold chains and identify opportunities for reductions. 
• Collaborate and undertake food cold chain needs assessments and develop costed and sequenced National Cooling Action Plans, backed with specific actions and financing.
• Implement and enforce ambitious minimum efficiency standards, and monitoring and enforcement to prevent illegal imports of inefficient food cold chain equipment and refrigerants.
• Run large-scale system demonstrations to show positive impacts of sustainable cold chains, and how interventions can create sustainable and resilient solutions for scaling.
• Institute multidisciplinary centres for food cold chain development at the national or regional level.

About the United Nations Environment Programme (UNEP)

UNEP is the leading global voice on the environment. It provides leadership and encourages partnership in caring for the environment by inspiring, informing and enabling nations and peoples to improve their quality of life without compromising that of future generations.

About the Food and Agriculture Organization (FAO)

FAO is a specialized agency of the United Nations that leads international efforts to defeat hunger. Its goal is to achieve food security for all and make sure that people have regular access to enough high-quality food to lead active healthy lives. With over 194-Member Nations, FAO works in over 130 countries worldwide.

About the Cool Coalition 

The Cool Coalition is a global multi-stakeholder network government, cities, international organizations, businesses, finance, academia, and civil society groups committed to a rapid global transition to efficient and climate-friendly cooling. The Coalition is one of the official outcomes and “Transformation Initiatives” put forward by the Executive Office of the Secretary-General for the UN Climate Action Summit. The Coalition’s Secretariat is hosted by the United Nations Environment Programme.

About the Climate and Clean Air Coalition 

The Climate and Clean Air Coalition is a voluntary partnership of governments, intergovernmental organizations, businesses, scientific institutions and civil society organizations committed to improving air quality and protecting the climate through actions to reduce short-lived climate pollutants, including methane, black carbon, tropospheric ozone, and hydrofluorocarbons (HFCs). The Coalition’s Secretariat is hosted by the United Nations Environment Programme.

Earth-sun distance dramatically alters seasons in the equatorial Pacific in a 22,000-year cycle

An unrecognized effect boosts or diminishes the Pacific cold tongue, likely impacting El Niño/La Niña events and North American weather

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - BERKELEY

 

IMAGE: A TEMPERATURE MAP OF THE PACIFIC OCEAN FOR DECEMBER 1993 SHOWING A COLD (BLUE) TONGUE OF SURFACE WATER STRETCHING WESTWARD ALONG THE EQUATOR FROM THE COAST OF SOUTH AMERICA. THE TEMPERATURE AND EXTENT OF THE COLD TONGUE CHANGES WITH THE SEASONS, BUT NEW CLIMATE SIMULATIONS SHOW THAT THE ANNUAL CHANGE IN EARTH’S DISTANCE FROM THE SUN ALSO AFFECTS THE COLD TONGUE SEASONAL CYCLE. THIS INFLUENCES EL NIÑO CONDITIONS THAT IMPACT WEATHER IN NORTH AMERICA AND GLOBALLY. view more 

CREDIT: JOHN CHIANG, UC BERKELEY

Weather and climate modelers understand pretty well how seasonal winds and ocean currents affect El Niño patterns in the eastern equatorial Pacific Ocean, impacting weather across the United States and sometimes worldwide.

But new computer simulations show that one driver of annual weather cycles in that region — in particular, a cold tongue of surface waters stretching westward along the equator from the coast of South America — has gone unrecognized: the changing distance between Earth and the sun.

The cold tongue, in turn, influences the El Niño-Southern Oscillation (ENSO), which impacts weather in California, much of North America, and often globally.

The Earth-sun distance slowly varies over the course of the year because Earth’s orbit is slightly elliptical. Currently, at its closest approach — perihelion — Earth is about 3 million miles closer to the sun than at its farthest point, or aphelion. As a result, sunlight is about 7% more intense at perihelion than at aphelion.

Research led by the University of California, Berkeley, demonstrates that the slight yearly change in our distance from the sun can have a large effect on the annual cycle of the cold tongue. This is distinct from the effect of Earth’s axial tilt on the seasons, which is currently understood to cause the annual cycle of the cold tongue.

Because the period of the annual cycle arising from the tilt and distance effects are slightly different, their combined effects vary over time, said lead researcher John Chiang, UC Berkeley professor of geography.

“The curious thing is that the annual cycle from the distance effect is slightly longer than that for tilt — around 25 minutes, currently — so over a span of about 11,000 years, the two annual cycles go from being in phase to out of phase, and the net seasonality undergoes a remarkable change, as a result,” Chiang said.

Chiang noted that the distance effect is already incorporated into climate models — though its effect on the equatorial Pacific was not recognized until now — and his findings will not alter weather predictions or climate projections. But the 22,000-year phase cycle may have had long-term, historical effects. Earth’s orbital precession is known to have affected the timing of the ice ages, for example.

The distance effect — and its 22,000-year variation — also may affect other weather systems on Earth. The ENSO, which also originates in the equatorial Pacific, is likely affected because its workings are closely tied to the seasonal cycle of the cold tongue.

“Theory tells us that the seasonal cycle of the cold tongue plays a key role in the development and termination of ENSO events,” said Alyssa Atwood, a former UC Berkeley postdoctoral fellow who is now an assistant professor at Florida State University in Tallahassee. “Because of this, many of ENSO’s key characteristics are synced to the seasonal cycle.”

For example, ENSO events tend to peak during Northern Hemisphere winters, she said, and they don’t typically persist beyond northern or boreal spring months, which scientists refer to as the “spring predictability barrier.” Because of these linkages, it is reasonable to expect that the distance effect could also have a major impact on ENSO — something that should be examined in future studies.

“Very little attention has been paid to the cold tongue seasonal cycle because most people think it's solved. There's nothing interesting there,” Chiang said. “What this research shows is that it's not solved. There's still a mystery there. Our result also begs the question whether other regions on Earth may also have a significant distance effect contribution to their seasonal cycle.”

“We learn in science classes as early as grade school that the seasons are caused by the tilt of Earth’s axis,” added co-author Anthony Broccoli of Rutgers University. “This is certainly true and has been well understood for centuries. Although the effect of the Earth-sun distance has also been recognized, our study indicates that this ‘distance effect’ may be a more important effect on climate than had been recognized previously.”

Chiang, Atwood and Broccoli and their colleagues reported their findings today in the journal Nature  

CAPTION

As Earth gets closer to the sun in its elliptical orbit, the continent-dominated hemisphere heats up more than the ocean -dominated hemisphere, generating trade winds that affect the cold tongue and likely the El Niño/La Niña cycle that determines whether California gets rain or drought.

CREDIT

John Chiang, UC Berkeley

Two distinct yearly cycles affect Pacific cold tongue

The main driver of global weather changes is seasonal change. Earth’s equator is tilted relative to its orbit around the sun, so the Northern and Southern hemispheres are illuminated differently. When the sun shines directly overhead in the north, it’s warmer in the north and colder in the south, and vice versa.

These yearly changes have major effects on the Pacific equatorial trade winds, which blow from southeast to northwest across the south and equatorial Pacific and push surface waters westward, causing upwelling of cold water along the equator that creates a tongue of cold surface water that stretches from Ecuador across the Pacific — almost one-quarter the circumference of the planet.

The yearly hemispheric changes in seasonal temperature alters the strength of the trades, and thus cause a yearly cycle in the temperature of the cold tongue. This, in turn, has a major influence on ENSO, which typically peaks during Northern Hemisphere winter.

The occurrence of El Niño — or its opposite, La Niña — helps determines whether California and the West Coast will have a wet or dry winter, but also whether the Midwest and parts of Asia will have rain or drought.

“In studying past climates, much effort has been dedicated to trying to understand if variability in the tropical Pacific Ocean — that is, the El Niño/La Niña cycle — has changed in the past,” Broccoli said. “We chose to focus instead on the yearly cycle of ocean temperatures in the eastern Pacific cold tongue. Our study found that the timing of perihelion — that is, the point at which the earth is closest to the sun — has an important influence on climate in the tropical Pacific."

In 2015, Broccoli, co-director of the Rutgers Climate Institute, along with his then-graduate student Michael Erb, employed a computer climate model to show that the distance changes caused by Earth’s elliptical orbit dramatically altered the cold tongue yearly cycle. But climate modelers mostly ignored the result, Chiang said.

“Our field is focused on El Niño, and we thought that the seasonal cycle was solved. But then we realized that the result by Erb and Broccoli challenged this assumption,” he said.

Chiang and his colleagues, including Broccoli and Atwood, examined similar simulations using four different climate models and confirmed the result. But the team went further to show how the distance effect works.

Earth’s ‘marine’ and ‘continental’ hemispheres

The key distinction is that changes in the sun’s distance from Earth don’t affect the Northern and Southern hemispheres differently, which is what gives rise to the seasonal effect due to Earth’s axial tilt. Instead, they warm the eastern “continental hemisphere” dominated by the North and South American and African and Eurasian landmasses, more than it warms the Western Hemisphere — what he calls the marine hemisphere, because it is dominated by the Pacific Ocean.

“The traditional way of thinking about monsoons is that the Northern Hemisphere warms up relative to the Southern Hemisphere, generating winds onto land that bring monsoon rains,” Chiang said. “But here, we’re actually talking about east-west, not north-south, temperature differences that cause the winds. The distance effect is operating through the same mechanism as the seasonal monsoon rains, but the wind changes are coming from this east-west monsoon.”

The winds generated by this differential heating of the marine and continental hemispheres alter the yearly variation of the easterly trades in the western equatorial Pacific, and thereby the cold tongue.

“When Earth is closest to the sun, these winds are strong. In the offseason, when the sun is at its furthest, these winds become weak,” Chiang said. “Those wind changes are then propagated to the Eastern Pacific through the thermocline, and basically it drives an annual cycle of the cold tongue, as a result.”

Today, Chiang said, the distance effect on the cold tongue is about one-third the strength of the tilt effect, and they enhance one another, leading to a strong annual cycle of the cold tongue. About 6,000 years ago, they canceled one another, yielding a muted annual cycle of the cold tongue. In the past, when Earth’s orbit was more elliptical, the distance effect on the cold tongue would have been larger and could have led to a more complete cancellation when out of phase.

Though Chiang and his colleagues did not examine the effect of such a cancellation, this would potentially have had a worldwide effect on weather patterns.

Chiang emphasized that the distance effect on climate, while clear in climate model simulations, would not be evident from observations because it cannot be readily distinguished from the tilt effect.

“This study is purely model based. So, it is a prediction,” he said. “But this behavior is reproduced by a number of different models, at least four. And what we did in this study is to explain why this happens. And in the process, we've discovered another annual cycle of the cold tongue that's driven by Earth's eccentricity.”

Atwood noted that, unlike the robust changes to the cold tongue seasonal cycle, changes to ENSO tend to be model-dependent.

“While ENSO remains a challenge for climate models, we can look beyond climate model simulations to the paleoclimate record to investigate the connection between changes in the annual cycle of the cold tongue and ENSO in the past,” she said. “To date, paleoclimate records from the tropical Pacific have largely been interpreted in terms of past changes in ENSO, but our study underscores the need to separate changes in the cold tongue annual cycle from changes in ENSO.”

Chiang’s colleagues, in addition to Broccoli and Atwood, are Daniel Vimont of the University of Wisconsin in Madison; former UC Berkeley undergraduate Paul Nicknish, now a graduate student at the Massachusetts Institute of Technology; William Roberts of Northumbria University in Newcastle-upon-Tyne in the United Kingdom; and Clay Tabor of the University of Connecticut in Storrs. Chiang conducted part of the research while on sabbatical at the Research Institute for Environmental Changes of the Academia Sinica in Taipei, Taiwan.

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JOURNAL

Nature

DOI

10.1038/s41586-022-05240-9 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Two annual cycles of the Pacific cold tongue under orbital precession

ARTICLE PUBLICATION DATE

9-Nov-2022

Turning concrete into a clean energy source

UTA-led partnership aims to manufacture concrete that captures carbon emissions

Grant and Award Announcement

UNIVERSITY OF TEXAS AT ARLINGTON

 

IMAGE: MARIA KONSTAS-GDOUTOS view more 

CREDIT: UT ARLINGTON

Concrete is the most widely used manufactured material worldwide—and one of the largest contributors to greenhouse gas emissions, accounting for at least 8% of global energy-related carbon dioxide emissions.

Maria Konsta-Gdoutos, a University of Texas at Arlington civil engineering professor and associate director of the Center for Advanced Construction Materials (CACM), is leading an international effort to decarbonize concrete production and promote its use as a renewable energy generator.

“We will pioneer TE-CO2NCRETE, a thermoelectric carbon-neutral concrete, that will exhibit a high carbon dioxide uptake potential and storage capacity,” Konsta-Gdoutos said. “Engineering the nanostructure of concrete also will allow the material to capture thermal energy from the surroundings and convert it into usable electrical energy, leading to the development of a novel technology for renewable electricity and higher efficiency power source.” 

A $1.5 million National Science Foundation grant is supporting this effort, which also involves another U.S. university and five European institutions. The U.S. partner is the University of Wisconsin-Milwaukee’s Concrete Sustainability and Resilience Center, which is known for experimental research on design, multiscale characterization and implementation of sustainable multifunctional concrete utilizing carbon-based waste byproducts and graphene-based nanomaterials. International partners include the French National Center for Scientific Research, which is an expert on atomistic simulation techniques useful in renewable energy research; the Technical Universities in Dresden and Berlin, Germany; and the Politecnico di Torino in Torino, Italy.

Other stakeholders include the Portland Cement Association, a leading research and market organization serving cement manufacturers, and the American Concrete Institute. Both are actively engaged to accelerate and advance solutions to reach carbon neutrality, Konsta-Gdoutos said.

The aim of the partnership is to advance technological know-how for net zero carbon concrete at a global scale, picking up the pace set by the Paris Agreement to reduce greenhouse gas emissions 52% by 2030.

Konsta-Gdoutos said all partners are authorities in carbonated construction materials and energy-autonomous building materials and are equipped in handling various parts of the project. Further, CACM’s labs contain a sub-10-nanometer imaging/mapping NanoIR AFM spectrometer, the only one at a university in the United States.

Melanie Sattler, professor and interim chair of the Department of Civil Engineering, said the international collaboration connects research to the workforce.

“The partnership’s readiness to scale up and establish long-lasting bonds of international research are extensive,” Sattler said. “I could see industry stakeholders and national and international agencies become meaningful partners of the workforce connection.”

University of Missouri is helping the aviation industry go “green”

Using part of a $12.8 million grant from the U.S. Department of Energy, MU researchers are working with an interdisciplinary group to optimize green energy for aviation use.

Grant and Award Announcement

UNIVERSITY OF MISSOURI-COLUMBIA

 

IMAGE: GABRIEL LEMES JORGE, A POSTDOCTORAL FELLOW AT MU, CHECKS ON PLANT SAMPLES IN JAY J. THELEN'S LAB AT THE CHRISTOPHER S. BOND LIFE SCIENCES CENTER. view more 

CREDIT: UNIVERSITY OF MISSOURI

While biodiesel and ethanol are two forms of biofuel used to power today’s cars and trucks, one area of the transportation sector that’s still developing a viable biofuel solution is the aviation industry. Now, an interdisciplinary team of researchers from across the United States, including the University of Missouri, is working to develop a sustainable “green energy” source of biofuel — an energy source commonly produced from vegetable oil — as an alternative to the petroleum-based fossil fuel widely used in the aviation industry.

The team, using a $12.8 million grant from the U.S. Department of Energy (DOE), will explore how two cover crops — plants grown to capture carbon from the Earth’s atmosphere to help reduce greenhouse gas emissions — called camelina and pennycress could be genetically modified to produce higher overall quantities of a specialty seed oil. The team’s goal is to mass-produce a vegetable oil capable of being used as a biofuel for aviation purposes, according to Jay J. Thelen, a professor of biochemistry in the College of Agriculture, Food and Natural Resources, who is also an investigator in the Christopher S. Bond Life Sciences Center.

“We’re trying to increase the overall amount of seed oil produced by both crops, as well as changing the oil composition from 18 to 10 carbons, which makes the oil more fluid for use in the aviation industry,” Thelen said.

Edgar Cahoon, the George W. Holmes Professor of Biochemistry at the University of Nebraska-Lincoln and lead researcher on the grant, is exploring how to take genes from the cuphea plant — known for their medium-chain oil producing traits — and using biotechnology to transfer them to camelina and pennycress. Additionally, using $2.7 million of the $12.8 million grant, MU’s team is taking three of the Thelen lab’s patented approaches for improving overall oil content in plant seeds and applying them to Cahoon’s existing research on this topic.

MU’s team hopes to figure out why camelina and pennycress are not producing the optimal amount of seed oil after cuphea’s medium-chain oil producing traits are introduced to both plants through genetic engineering.

“When we move genes from cuphea into camelina or pennycress, we’re going to do large-scale transcriptomics and proteomics to try to understand how the plant is responding to this new gene and see where the bottlenecks lie that Cahoon’s team is experiencing,” Thelen said. “With that knowledge we can complete the design, build, test, learn cycle in order to incrementally raise the levels of the medium-chain fatty acids in camelina or pennycress until we meet the optimal level.”

To do this, MU’s team is using advanced proteomics technologies, including sophisticated state-of-the-art mass spectrometry instrumentation located in both Thelen’s lab and the Charles W. Gehrke Proteomics Center at MU. The group will also use cutting-edge biotechnology approaches to gain knowledge about how the plants are responding to the genetic engineering, Thelen said.

“Leveraging my lab’s expertise in both discovery and targeted proteomics will provide us with the basic knowledge we need to help understand why engineering high levels of medium-chain oils in camelina and pennycress has been elusive so far,” Thelen said.

This research creates a large amount of data to be analyzed, so internationally renowned bioinformatics researchers Dong Xu from the MU College of Engineering and Trupti Joshi from the MU School of Medicine are joining Thelen to assist him with that part of the project. MU’s team will add the information they collect to a related project by Xu which involves building an online database on the topic of metabolic engineering of oilseed plants.

Since cover crops can be planted during the non-growing season and can also be grown in soils with less-than-ideal planting conditions, Thelen hopes the team’s work could provide farmers across the U.S. with an additional option to earn a profit beyond the traditional growing and harvesting seasons.    

“At the moment, these cover crops [camelina and pennycress] are mostly planted to earn federal carbon credits, but they are not harvested by farmers,” Thelen said.

In addition to MU and the University of Nebraska-Lincoln, the team includes researchers from the Donald Danforth Plant Science Center, Kansas State University, Montana State University, University of Colorado-Boulder, University of Minnesota and Washington State University.  

The grant was awarded under the DOE program Biosystems Design to Enable Safe Production of Next-generation Biofuels, Bioproducts and Biomaterials.

Editor’s Note: Joshi is the translational bioinformatics faculty lead for NextGen Biomedical Informatics (BMI) and the MU School of Medicine. Dong Xu is a Curators’ Distinguished Professor in the Department of Electrical Engineering and Computer Science. Both have faculty appointments in the Christopher S. Bond Life Sciences Center and the Institute for Data Science and Informatics at MU.