New research published in the journal Psychological Science shows that both online and in-person psychological interventions — tactics specifically designed to boost subjective well-being — have positive effects on self-reported physical health. The online and in-person interventions were equally effective.

“Though prior studies have shown that happier people tend to have better cardiovascular health and immune-system responses than their less happy counterparts,” said Kostadin Kushlev, a professor in Georgetown University’s Department of Psychology and one of the authors of the paper, “our research is one of the first randomized controlled trials to suggest that increasing the psychological well-being even of generally healthy adults can have benefits to their physical health.”

Intervention for Healthy Outcomes

Over the course of six months, Kushlev and his colleagues at the University of Virginia and the University of British Columbia examined how improving the subjective well-being of people who were not hospitalized or otherwise undergoing medical treatment affected their physical health.

A group of 155 adults between the ages of 25 and 75 were randomly assigned either to a wait-list control condition or a 12-week positive psychological intervention that addressed three different sources of happiness: the “Core Self,” the “Experiential Self,” and the “Social Self.”

The first 3 weeks of the program focused on the Core Self, helping individuals identify their personal values, strengths, and goals. The next 5 weeks focused on the Experiential Self, covering emotion regulation and mindfulness. This phase also gave participants tools to identify maladaptive patterns of thinking. The final 4 weeks of the program addressed the Social Self, teaching techniques to cultivate gratitude, foster positive social interactions, and engage more with their community.

The program, called Enduring Happiness and Continued Self-Enhancement (ENHANCE), consisted of weekly modules either led by a trained clinician or completed individually using a customized online platform. None of the modules focused on promoting physical health or health behaviors, such as sleep, exercise, or diet.

Each module featured an hour-long lesson with information and exercises; a weekly writing assignment, such as journaling; and an active behavioral component, such as guided meditation.

“All of the activities were evidence-based tools to increase subjective well-being,” Kushlev noted.

When the program concluded, the participants were given individual evaluations and recommendations of which modules would be most effective at improving their happiness in the long term. Three months after the conclusion of the trial, researchers followed up with the participants to evaluate their well-being and health.

A Happy Future

Participants who received the intervention reported increasing levels of subjective well-being over the course of the 12-week program. They also reported fewer sick days than control participants throughout the program and 3 months after it ended.

The online mode of administering the program was shown to be as effective as the in-person mode led by trained facilitators.

“These results speak to the potential of such interventions to be scaled in ways that reach more people in environments such as college campuses to help increase happiness and promote better mental health among students,” Kushlev said.

A methane seep is a location where methane gas escapes from an underground reservoir and into the ocean. Methane seeps have been found throughout the world’s oceans, but the one discovered in the Ross Sea was the first active seep found in Antarctica, said Andrew Thurber, a marine ecologist at Oregon State University.

“Methane is the second-most effective gas at warming our atmosphere and the Antarctic has vast reservoirs that are likely to open up as ice sheets retreat due to climate change,” Thurber said. “This is a significant discovery that can help fill a large hole in our understanding of the methane cycle.”

The researchers’ findings were published today in the journal Proceedings of the Royal Society B. Co-authors are Sarah Seabrook and Rory Welsh, who were graduate students at OSU during the expeditions. The research was supported by the National Science Foundation.

Methane is a greenhouse gas that is 25 times more powerful than carbon dioxide at warming the planet. Most methane in the ocean water and sediment is kept out of the atmosphere by microbes that consume it.

Thurber and his colleagues discovered that the microbes around the Antarctic seep are fundamentally different that those found elsewhere in the world’s oceans. This helps researchers better understand methane cycles and the factors that determine whether methane will reach the atmosphere and contribute to further warming, Thurber said.

The Ross Sea seep was discovered in an area that scientists have studied for more than 60 years, but the seep was not active until 2011, said Thurber, an assistant professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences and the College of Science’s Department of Microbiology.

An expansive microbial mat, about 70 meters long by a meter across, formed on the sea floor about 10 meters below the frozen ocean surface. These mats, which are produced by bacteria that exist in a symbiotic relationship with methane consumers, are a telltale indication of the presence of a seep, said Thurber.

“The microbial mat is the road sign that there’s a methane seep here,” Thurber said. “We don’t know what caused these seeps to turn on. We needed some dumb luck to find an active one, and we got it.”

Thurber happened to be in Antarctica in 2012 when another researcher told him about a “microbial waterfall” and thought it was something he should look at. Thurber was able to confirm the seep’s presence, collect samples and analyze the seep and its environment. When he returned to the site in 2016 to conduct further study, he also discovered a second seep nearby.

Antarctica is believed to contain as much as 25 percent of Earth’s marine methane. Having an active seep to study gives researchers new understanding of the methane cycle and how that process might differ in Antarctica compared to other places on the planet, Thurber said.

For example, researchers have found that the most common type of microbe that consumes methane took five years to show up at the seep site and even then those microbes were not consuming all of the methane, Thurber said. That means some methane is being released and is likely working its way into the atmosphere.

Studying the site over a five-year time span allowed researchers to see how microbes respond to the formation of a seep, said Seabrook, who earned her doctorate at OSU and is now a post-doctoral scholar at the National Institute of Water and Atmospheric Research in Wellington, New Zealand.

“What was really interesting and exciting was that the microbial community did not develop as we would have predicted based on other methane seeps we have studied around the globe,” she said.

Researchers had assumed that microbes should respond really quickly to changes in the environment, but that wasn’t reflected in what OSU’s team saw in Antarctica, Thurber said.

“To add to the mystery of the Antarctic seeps, the microbes we found were the ones we least expected to see at this location,” he said. There may be a succession pattern for microbes, with certain groups arriving first and those that are most effective at eating methane arriving later.

“We’ve never had the opportunity to study a seep as its forming or one in Antarctica, because of this discovery we can now uncover whether seeps just function differently in Antarctica or whether it may take years for the microbial communities to become adapted,” Thurber said.

“Animals in Antarctica are very different than elsewhere in the world as the continent has been separated from the rest of the globe for more than 30 million years — a long time for evolution to act,” he said. “That has resulted in a remarkable diversity of fauna that we only find there. That may also contribute to the differences in microbes there.”

It is important to understand how methane seeps behave in this environment so researchers can begin factoring those differences into climate change models, Thurber said. He hopes to return to the site to monitor its evolution and conduct further research.

Fossils show that Tongoenas burleyi, a newly described genus and species, inhabited the Pacific islands for at least 60,000 years, but vanished within a century or two of human arrival around 2,850 years ago.

Unlike the dodo and the extinct Viti Levu giant pigeon of Fiji, however, T. burleyi could fly. This canopy-dwelling species co-evolved with fruit-bearing trees in the mango, guava and chinaberry families, acting as an essential forest cultivator by spreading seeds to new locations. The size of a large duck, Tongoenas burleyi was likely capable of swallowing fruit as big as a tennis ball, said study lead author David Steadman, curator of ornithology at the Florida Museum of Natural History.

“Some of these trees have big, fleshy fruit, clearly adapted for a big pigeon to gulp whole and pass the seeds,” Steadman said. “Of the fruit-eating pigeons, this bird is the largest and could have gulped bigger canopy fruit than any others. It takes co-evolution to the extreme.”

The absence of T. burleyi from the Tongan islands could threaten the long-term survival of local trees that depended on the pigeon as a seed transporter, said study co-author Oona Takano, a doctoral student at the University of New Mexico.

“T. burleyi provided an important service by moving seeds to other islands,” said Takano, who was previously a research assistant at the Florida Museum. “The pigeon species on Tonga today are too small to eat large fruits, which imperils certain fruit trees.”

When Steadman first found T. burleyi fossils in a cave on the Tongan island of ‘Eua, he was immediately impressed by their size: The bird was about 20 inches long, not including the tail, and weighed at least five times as much as the average city pigeon.

“I said, ‘Oh my God, I’ve never seen a pigeon that big,'” Steadman said. “It was clearly something different.”

Once he and archaeologist David Burley of Simon Fraser University — who is also the species’s namesake — began excavating charred and broken remains of T. burleyi at archaeological sites, “we knew it was another human-caused extinction,” Steadman said. “Pigeons and doves just plain taste good.”

Columbids, the family that includes pigeons and doves, had few predators or competitors before people reached the Pacific islands, he said. The region was devoid of primates and carnivores such as cats, dogs and weasels, and hawks and owls were absent from many islands. The birds flourished in this nurturing environment, diversifying over the past 30-40 million years.

Today, the Pacific islands are the global epicenter of pigeon and dove diversity, with more than 90 species, ranging from fruit doves as light as a handful of raisins to the turkey-sized, ground-dwelling crowned pigeon of New Guinea. But the number and distribution of birds in the region is a shadow of what it once was, Steadman said. Tonga’s four remaining species of pigeons and doves represent less than half of the islands’ historic diversity.

“This is another example of how looking at the modern fauna doesn’t yield a complete picture of a region’s diversity,” he said.

Steadman and Takano analyzed the features of columbid hindlimbs, dividing them into three groups: tree-dwelling species, ground-dwellers and those that live both on the ground and in trees. Pigeons and doves that spend most of their time in the canopy tend to have shorter legs, more suitable for perching and gripping in high winds. Those that forage for seeds on the ground have longer legs adapted for walking and running. Birds that flit between the understory and the forest floor have legs that are a blend of the characteristics of the other two groups.

The researchers found surprising agreement between the groupings based on leg characteristics and molecular data: In other words, canopy-dwelling pigeons tend to be more closely related to one another than to birds in the other two groups.

“Given that there are 350 species of pigeons and doves, people might suspect these big changes in lifestyle evolved independently many times,” Steadman said. “But right now, we don’t have evidence that it happened more than once — at least in the tropical Pacific.”

The relatively short hindlimbs of T. burleyi mark it as a canopy-dwelling species. Steadman hypothesized the species featured the bright, even gaudy, plumage of other pigeons that live in treetops, where intense colors provide better camouflage than the muted browns and grays of pigeons that live on the ground.

The researchers dedicated the study to the memory of W. Arthur “Art” Whistler, whose expertise in West Polynesian botany was unsurpassed, Steadman said. Whistler died from COVID-19 in April.

“There wasn’t a plant on Fiji or Tonga that Art didn’t know, including all of the pigeon-dispersed fruits,” Steadman said. “He was a true plant nerd and complete salt of the earth. He always made time for people.”

Painstaking excavations of Chiquihuite Cave, located in a mountainous area in northern Mexico controlled by drugs cartels, uncovered nearly 2000 stone tools from a small section of the high-altitude cave.

Archaeological analysis of the tools and DNA analysis of the sediment in the cave uncovered a new story of the colonisation of the Americas which now traces evidence of the first Americans back to 25,000-30,000 years ago.

The results, which have been published in Nature today (July 22 2020), challenge the commonly held theory that the Clovis people were the first human inhabitants of the Americas 15,000 years ago.

DNA scientist Professor Eske Willerslev, of St John’s College, University of Cambridge, and director of The Lundbeck Foundation GeoGenetics Centre, University of Copenhagen, led the study with archaeologist Dr Ciprian Ardelean, of the University of Zacatecas in Mexico.

Professor Willerslev said: “For decades people have passionately debated when the first humans entered the Americas. Chiquihuite Cave will create a lot more debate as it is the first site that dates the arrival of people to the continent to around 30,000 years ago — 15,000 years earlier than previously thought. These early visitors didn’t occupy the cave continuously, we think people spent part of the year there using it as a winter or summer shelter, or as a base to hunt during migration. This could be the Americas oldest ever hotel.”

The 10-year long research project raises more questions about the early humans who lived in the Americas than it solves.

Dr Ardelean said: “We don’t know who they were, where they came from or where they went. They are a complete enigma. We falsely assume that the indigenous populations in the Americas today are direct descendants from the earliest Americans, but now we do not think that is the case.

“By the time the famous Clovis population entered America, the very early Americans had disappeared thousands of years before. There could have been many failed colonisations that were lost in time and did not leave genetic traces in the population today.”

Chiquihuite Cave is a high-altitude site, 2750 metres above sea level. Nearly 2000 stone tools and small tool fragments, known as flakes, were discovered. DNA analysis of the plant and animal remains from the sediment packed around the tools in the cave dates the tools and the human occupation of the site to 25,000-30,000 years ago. Human DNA was not found which adds weight to the theory that the early people didn’t stay for long in the cave.

Dr Mikkel Winther Pedersen, a geneticist from the University of Copenhagen and one of the first authors of the paper, said: “We identified DNA from a wide range of animals including black bears, rodents, bats, voles and even kangaroo rats. We think these early people would probably have come back for a few months a year to exploit reoccurring natural resources available to them and then move on. Probably when herds of large mammals would have been in the area and who had little experience with humans so they would have been easy prey. The location of Chiquihuite Cave definitely rewrites what has conventionally been taught in history and archaeology and shows that we need to rethink where we look for sites of the earliest people in Americas.”

The Chiquihuite Cave site is very difficult to reach and would have been a good vantage point for the early people to defend themselves from as they could look out for miles over the valley without being seen. It is in an area of Mexico that is now controlled by drugs cartels. The academics were escorted by armed police to the base of the mountain before they made their way up to the cave on foot.

Dr Pedersen said: “It was an unforgettable experience. It is a very unsafe place to travel so we were accompanied by Mexican police officers in armoured cars to the foot of the mountain. We left before sunrise to climb up to the cave so that we weren’t spotted.”

The visiting DNA scientists slept in the cave during their research visit and over the past 10 years Dr Ardelean has spent a number of months living in the cave to carry out the painstaking excavations.

Dr Ardelean added: “The peopling of the Americas is the last holy grail in modern archaeology. Unconventional sites need to be taken seriously and we need to go out and intentionally look for them. This site doesn’t solve anything, it just shows that these early sites exist. We are dealing with a handful of humans from thousands of years ago so we cannot expect the signals to be very clear. We have literally dug deeper than anyone has done in the past.”

The earliest human DNA from the Americas currently remains at 12,400 years ago, Dr Ardelean explained: “We have shown the previously long held date of human presence is not the oldest date for populating the Americas, it is the explosion date of populating the Americas.”

Professor Willerslev concluded: “I will never forget being part of this research, it was an unbelievable experience. The implications of these findings are as important, if not more important, than the finding itself. This is only the start of the next chapter in the hotly debated early peopling of the Americas.”

The study, published July 22 in Nature, focused on the Wilkes Basin, one of several bowl-like basins at the edges of the ice sheet that are considered vulnerable to melting because the ice rests on land that is below sea level. The Wilkes Basin currently holds enough ice to raise sea level by 3 to 4 meters (10 to 13 feet).

Ice flows slowly through the basins from the interior of the continent out to the floating ice shelves at the margins. Ice loss causes the grounding line — the point at which the ice loses contact with the ground and starts floating — to shift inland, explained first author Terrence Blackburn, assistant professor of Earth and planetary sciences at UC Santa Cruz.

“Our data shows that the grounding line in the Wilkes Basin retreated 700 kilometers [435 miles] inland during one of the last really warm interglacials, when global temperatures were 1 to 2 degrees Celsius warmer than now,” Blackburn said. “That probably contributed 3 to 4 meters to global sea level rise, with Greenland and West Antarctica together contributing another 10 meters.”

In other words, a period of global warming comparable to what is expected under current scenarios for humanmade greenhouse gas emissions resulted in an increase in sea level of around 13 meters (43 feet). Of course, this wouldn’t happen all at once — it takes time for that much ice to melt.

“We’ve opened the freezer door, but that block of ice is still cold and it’s not going anywhere in the short term,” Blackburn said. “To understand what will happen over longer time scales, we need to see what happened under comparable conditions in the past.”

The problem with studying the interglacial periods during the Pleistocene is that they all ended in another ice age when the ice sheet advanced again and covered up the evidence. For the new study, Blackburn and his colleagues used a novel technique based on isotope measurements in mineral deposits that record past changes in subglacial fluids.

Uranium-234 (U-234) is an isotope of uranium that accumulates very slowly in water that is in contact with rocks due to the high-energy decay of uranium-238. This happens everywhere, but in most places hydrological processes carry water away from sources of enrichment, and the U-234 gets diluted in large bodies of water. In Antarctica, however, water is trapped at the base of the ice sheet and moves very slowly as long as the ice is stable, allowing U-234 to build up to very high levels over long periods of time.

Blackburn explained that the ice sheet acts like an insulating blanket, so that heat from Earth’s interior causes melting at the base. But temperatures are colder where the ice is thinner at the margins of the ice sheet, causing subglacial water to refreeze.

“Water flowing beneath the ice starts refreezing at the edges, which concentrates all the dissolved minerals until it becomes supersaturated and the minerals precipitate out to form deposits of opal or calcite,” he said. “Those deposits trap uranium-234, so we can date the deposits and measure their composition, and we can track that through time to get a deep history of the composition of water under the ice sheet.”

What that history suggests is that the U-234 in subglacial water in the Wilkes Basin was flushed out during the interglacial period 400,000 years ago as the ice melted and the grounding line retreated. That reset the U-234 concentration to low background levels, and accumulation then restarted when the ice advanced again.

Blackburn noted that present-day evidence for the accumulation of U-234 in subglacial fluids can be found in the McMurdo Dry Valleys, the only place where Antarctic glaciers terminate on land. There, highly concentrated brines emerge from the glaciers in places such as Blood Falls, where the blood-red color comes from high iron concentrations in the brine.

“The isotopic compositions of those brines are comparable to the precipitates that we’ve dated from a range of locations, and they all share the characteristic U-234 enrichment,” Blackburn said. “The brines are what’s left when the subglacial fluids get all the way to the edge of the ice sheet.”

He said the new study was inspired by a 2016 paper in which researchers studying deep-sea corals reported evidence of a major change in ocean chemistry, including a spike in U-234, coinciding with the end of the last ice age, when the vast Laurentide Ice Sheet that covered much of North America melted.

“They speculated that it accumulates under the ice sheets and pointed to some possible sites in Antarctica where that might be happening,” Blackburn said. “I happened to be in one of those places at the time.”

So was his colleague, glaciologist Slawek Tulaczyk, a professor of Earth and planetary sciences at UC Santa Cruz. They discussed the paper and began planning this study, which eventually involved several UCSC faculty and students. The team collected some samples of mineral deposits themselves, but some of the most important samples used in the study were collected in the 1980s and archived at the Byrd Polar Rock Repository at Ohio State University.

MIT chemists have now developed a way to modify thermoset plastics with a chemical linker that makes the materials much easier to break down, but still allows them to retain the mechanical strength that makes them so useful.

In a study appearing today in Nature, the researchers showed that they could produce a degradable version of a thermoset plastic called pDCPD, break it down into a powder, and use the powder to create more pDCPD. They also proposed a theoretical model suggesting that their approach could be applicable to a wide range of plastics and other polymers, such as rubber.

“This work unveils a fundamental design principle that we believe is general to any kind of thermoset with this basic architecture,” says Jeremiah Johnson, an professor of chemistry at MIT and the senior author of the study.

Peyton Shieh, an American Cancer Society Postdoctoral Fellow at MIT, is the first author of the paper.

Hard to recycle

Thermosets are one of the two major classes of plastics, along with thermoplastics. Thermoplastics include polyethylene and polypropylene, which are used for plastic bags and other single-use plastics like food wrappers. These materials are made by heating up small pellets of plastic until they melt, then molding them into the desired shape and letting them cool back into a solid.

Thermoplastics, which make up about 75 percent of worldwide plastic production, can be recycled by heating them again until they become liquid, so they can be remolded into a new shape.

Thermoset plastics are made by a similar process, but once they are cooled from a liquid into a solid, it is very difficult to return them to a liquid state. That’s because the bonds that form between the polymer molecules are strong chemical attachments called covalent bonds, which are very difficult to break. When heated, thermoset plastics will typically burn before they can be remolded, Johnson says.

“Once they are set in a given shape, they’re in that shape for their lifetime,” he says. “There is often no easy way to recycle them.”

The MIT team wanted to develop a way to retain the positive attributes of thermoset plastics — their strength and durability — while making them easier to break down after use.

In a paper published last year, with Shieh as the lead author, Johnson’s group reported a way to create degradable polymers for drug delivery, by incorporating a building block, or monomer, containing a silyl ether group. This monomer is randomly distributed throughout the material, and when the material is exposed to acids, bases, or ions such as fluoride, the silyl ether bonds break.

The same type of chemical reaction used to synthesize those polymers is also used to make some thermoset plastics, including polydicyclopentadiene (pDCPD), which is used for body panels in trucks and buses.

Using the same strategy from their 2019 paper, the researchers added silyl ether monomers to the liquid precursors that form pDCPD. They found that if the silyl ether monomer made up between 7.5 and 10 percent of the overall material, pDCPD would retain its mechanical strength but could be broken down into a soluble powder upon exposure to fluoride ions.

“That was the first exciting thing we found,” Johnson says. “We can make pDCPD degradable while not hurting its useful mechanical properties.”

New materials

In the second phase of the study, the researchers tried to reuse the resulting powder to form a new pDCPD material. After dissolving the powder in the precursor solution used to make pDCPD, they were able to make new pDCPD thermosets from the recycled powder.

“That new material has nearly indistinguishable, and in some ways improved, mechanical properties compared to the original material,” Johnson says. “Showing that you can take the degradation products and remake the same thermoset again using the same process is exciting.”

The researchers believe that this general approach could be applied to other types of thermoset chemistry as well. In this study, they showed that using degradable monomers to form the individual strands of the polymers is much more effective than using degradable bonds to “cross-link” the strands together, which has been tried before. They believe that this cleavable strand approach could be used to generate many other kinds of degradable materials.

If the right kinds of degradable monomers can be found for other types of polymerization reactions, this approach could be used to make degradable versions of other thermoset materials such as acrylics, epoxies, silicones, or vulcanized rubber, Johnson says.

The researchers are now hoping to form a company to license and commercialize the technology. MIT has also granted Millipore Sigma a non-exclusive license to manufacture and sell the silyl ether monomers for research purposes.

Patrick Casey, a new product consultant at SP Insight and a mentor with MIT’s Deshpande Center for Technological Innovation, has been working with Johnson and Shieh to evaluate the technology, including performing some preliminary economic modeling and secondary market research.

“We have discussed this technology with some leading industry players, who tell us it promises to be good for stakeholders throughout the value chain,” Casey says. “Parts fabricators get a stream of low-cost recycled materials; equipment manufacturers, such as automotive companies, can meet their sustainability objectives; and recyclers get a new revenue stream from thermoset plastics. The consumers see a cost saving, and all of us get a cleaner environment.”

The research was funded by the National Science Foundation and the National Institutes of Health.