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In a new study, Harvard researchers took a granular approach to measuring the duration and frequency of suicidal thinking. With the help of a smartphone app, they were able to monitor participants multiple times a day over several weeks. These assessments revealed that suicidal thinking changes rapidly — with far shorter timescales than previously thought. And they offered a firmer sense of when suicidal desire is most predictive of future intent.

According to lead author Daniel Coppersmith, a Ph.D. student who works in a lab with the influential suicide researcher Matthew Nock, academic interest in suicide has increased in recent decades. But most of that research has focused on quantifying deaths or identifying risk. Few have sought to understand the fundamental contours of self-injurious thinking and behavior, information that can help better guide more effective prevention.

“A foundational aspect of other areas of science is observing natural phenomena as they unfold in the wild,” Coppersmith said. “Because we haven’t necessarily done that with suicide, we don’t have answers to basic questions like: How often do suicidal thoughts occur? How long do they last?”

The results were published this week in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

With the new study, Coppersmith, Nock, and their co-authors wanted to capture suicidal thinking as it occurred. Over 42 days, 105 adults with histories of suicidal thought received high-frequency pop-ups via the app with questions about their thoughts and feelings. One prompt asked about their level of suicidal desire at that very moment. Another concerned their current state of suicidal intent. Answers could be given on a scale from zero to 10, with 10 signaling a “very strong” desire or intent to kill oneself.

Crunching the data yielded several fresh insights. First, suicidal thinking tends toward brevity. Less frequent assessments put the average duration of elevated suicidal desire at 9½ hours. High-frequency testing put that average at 1.4 hours. “If we didn’t have this higher-frequency sample of data, we might infer that these types of thoughts last much longer,” Coppersmith said.

High-frequency sampling also confirmed previous studies that found suicidal thinking comes and goes. “Even among people who were recently suicidal, or have a history of suicidal behavior, they’re not thinking of suicide most of the time,” Coppersmith said. “Zero” was the most common answer given when ranking suicidal desire and suicidal intent.

Finally, different types of suicidal thinking operate according to different timescales. Current suicidal desire tends to predict future suicidal desire for about 20 hours, whereas suicidal intent is less common and can be predicted in timescales of only one to three hours. “We also have a better understanding of how these different constructs interact,” Coppersmith noted. “We were able to zoom in on the window in which desire is most predictive of future intent, which also seems to last around two to three hours.”

Nock, the Edgar Pierce Professor of Psychology and chair of Harvard’s Psychology Department, led a similar study 15 years ago. Back then Nock and his team relied on PalmPilots, which limited polling to a few times per day. Still, end-of-the-day self-assessments revealed that suicidal thinking had passed in an hour or less for the majority of study volunteers. “People were describing these short intervals,” Coppersmith said, “but [the researchers] weren’t collecting data within those time windows.”

Sometimes volunteers in the new study received a ping every few hours. At other times, an hourlong burst brought alerts every 10 minutes. Nock, who earned a MacArthur award in 2011 for his work in suicide research and prevention, likened this approach to technological advances in microscopes, which allow scientists to zoom in ever closer on their subjects.

The researchers emphasized that it’s safe to ask study participants about suicide, with no increased risk according to multiple meta-analyses. Throughout the process, Coppersmith added, volunteers were reminded via the app about the 988 Suicide & Crisis Lifeline and other resources.

While the findings are illuminating, suggesting that suicidal risk appears and recedes over extremely short periods of time, Coppersmith cautioned that more research is needed before concrete prescriptions can be offered. “But if we have a better understanding of the timescale,” he said, “we may eventually have a better understanding of when to deploy interventions.”

Vikings occupied Greenland from about 985 to 1450 A.D., farming and building communities before they abruptly abandoned their settlements. Why they disappeared has long been a puzzle, but a new paper from the Department of Earth and Planetary Sciences determines that one factor — rising sea level — likely played a major role.

“There are many theories as to what exactly happened” to drive the Vikings out, said Marisa J. Borreggine, lead author of “Sea-Level Rise in Southwest Greenland as a Contributor to Viking Abandonment,” published April 17 in the Proceedings of the National Academy of Sciences.

“There’s been a shift in the narrative away from the idea that the Vikings completely failed to adapt to the environment and toward arguments that they were faced with myriad challenges, ranging from social unrest, economic turmoil, political issues, and environmental change,” said Borreggine, a doctoral candidate in the Harvard Kenneth C. Griffin Graduate School of Arts and Sciences.

Amid those pressures, “the changing landscape would’ve proven to be yet another factor that challenged the Viking way of life,” said Borreggine, who works in the Mitrovica Group led by Frank B. Baird Jr. Professor of Science Jerry X. Mitrovica. This likely led “to a tipping point before they abandoned the settlement.”

The departure of these Viking settlers coincided with the beginning of the period known as the Little Ice Age, which had a particular impact on the North Atlantic. But while cooling and freezing might seem likely to lower sea levels, a variety of factors combined to have the opposite effect in Greenland.

With the waters of the North Atlantic “contributing to that new ice volume, intuition might suggest that sea level should go down,” Borreggine said. However, a closer look at previously published geomorphological and paleoclimate data and the researchers’ modeling of ice-sheet growth instead suggested glacial isostatic adjustment, “a process that leads to changes in the gravitational field, the rotation axis, and crustal deformation as the ice grows or melts,” said Borreggine.

In a first for this kind of research, “We were able to apply that analysis of nonuniform sea-level change and more accurate sea-level physics to this longstanding archeological question of, ‘Why exactly did Vikings abandon the eastern settlement?’”

The researchers’ striking answer: Not only were sea levels drawn up by gravity, other factors — including the subsidence of Greenland’s land mass — made the settlement more prone to flooding.

Focusing on the period of Viking habitation from 1000 to 1450, “there’s already a background trend of sea-level rise upon Viking arrival in the eastern settlement,” Borreggine said. “It’s been rising for a few thousand years.” But there’s also a local effect: “crustal subsidence, or the sinking of land and the gravitational pull of water toward the growing ice sheet.”

“Not only do you have the ground being pushed down, you also have the sea surface going up,” Borreggine said. “It’s a double whammy.”

During this period, researchers found that the settlers experienced “up to 3.3 meters of sea-level rise throughout their occupation.” For comparison’s sake, “that’s two to six times the rate of 20th-century sea-level rise. So it was pretty intense.”

Archaeological research into the life of the Vikings who settled in Greenland together with this novel application of sea-level science fleshed out this compelling story. Noting the partially drowned ruins of a Viking warehouse, Borreggine pointed out that one of the group’s analyses found that 75 percent of Viking sites are within 1,000 meters of an area of flooding. “This flooding was pervasive.”

The impact of rising seas can also be seen in the changing diet of the Vikings, as they shifted from their own agricultural products to more marine-based foods, perhaps as their fields became saturated with salt or flooded. Such a shift, said Borreggine, reveals “they were attempting to adapt to the rising sea level.”

This paper “shows the advantages of interdisciplinary research, bringing ideas from one field to another and contributing powerful new insights,” said Mitrovica.

If the lasting impact of sea-level rise sounds familiar in understanding current efforts to mitigate climate change, Borreggine noted the parallels — and one major difference.

“The Vikings didn’t really have a choice. They couldn’t stop the Little Ice Age. We can do work to mitigate climate change. The Vikings were locked into it.”

Director Oliver Stone — on campus earlier this month to promote his new film — argued nuclear power has been stigmatized and overlooked as a solution for meeting the world’s energy needs amid climate change.

Joining Stone at the “Nuclear Now” prescreening and panel at the Science Center was co-writer Joshua S. Goldstein; Richard Lester, associate provost at MIT; and moderator Daniel Schrag, director of Harvard’s Center for the Environment. The screening was introduced by psycholinguist Steven Pinker.

“Since Hollywood and mass media and the entertainment industry may have played some role in turning off an entire generation to nuclear power, it seems quite fitting that an icon of Hollywood is taking an active role in changing public consensus about nuclear power,” said Pinker, Harvard’s Johnstone Family Professor of Psychology.

“Nuclear Now” paints a picture of urgent need: global fossil fuel consumption rapidly increasing as developing countries modernize and populations grow. Nuclear power, it argues, is a clean, safe, reliable alternative to fossil fuels. The film covers the history of nuclear power, from key scientific discoveries to world powers harnessing it for mass destruction. It makes a point of separating nuclear power from nuclear bombs.

Addressing other safety fears tied to nuclear — the film posits that past accidents, caused by poor design, can be prevented with new reactors, and that despite Hollywood portrayals, meltdowns in Chernobyl, Three Mile Island, and Fukushima have led to far fewer casualties than the fatal levels of air pollution produced annually by coal and other fossil fuels. It argues small amounts of radiation have not been proven to cause health issues — imagery of dental offices and X-ray machines cross the screen.

Along with safety, cost was a major topic of the panel. Stone and Goldstein said the industry will right-size itself through repetition of production, while others expressed doubts.

“In South Korea, they’re building the same thing over and over, and cost comes down,” said Goldstein, who co-authored “A Bright Future: How Some Countries Have Solved Climate Change and the Rest Can” with Swedish engineer Staffan Qvist.

Schrag, who said he supports nuclear, relayed skepticism of the cost argument, adding that despite success abroad, estimates for production of U.S. reactors would still be in the tens of billions of dollars.

“To make even a significant fraction of a dent in the climate problem requires somehow a big change in the economics,” he said.

Stone proposed opening up production across borders. “The idea has to be expanded to China and Russia and above all we have to get away from this world animosity that I think the United States has played a large role in creating.”

Lester said innovation, along with repetition, can bring down nuclear costs, but bureaucracy is a barrier.

Several of his former students are innovators in the nuclear sector, including Jacob DeWitte and Caroline Cochran, co-founders of startup Oklo, which is featured in the film. “When you look at what it takes for these entrepreneurs to get their new designs through the regulatory game, it’s taken 10 years for one of the reactor types that was mentioned in the movie to be reviewed by regulators, and they’re still not through.”

From the audience, William Hogan, research director of Harvard Electricity Policy Group, said he sees a challenge for poorer countries. “What we do in the United States is important, but that’s not the problem. The problem is what’s going to happen to all these other places when they look at our story about how cheap it is in order to get to zero emissions and they say that looks pretty expensive.”

John Marshall, CEO of the Potential Energy Coalition, also speaking from the audience, said public opinion on nuclear may be shifting — only one in seven people are opposed, according to a survey his organization conducted in 2021.

Lester said he believes nuclear, despite its challenges, is unmatched in its potential to meet the world’s energy needs.

“We are not able to come close to addressing the climate change and decarbonization goals that have been set for the world without a lot more nuclear power. I just don’t think it can happen any other way.”

“Nuclear Now” opens to the public with a limited theatrical release on April 28.

The last thing Carolyn Elya expected to find in her backyard were zombies.

Elya was studying microbes carried by wild fruit flies while a graduate student at the University of California, Berkeley. The discovery of some dead ones that had been infected by Entomophthora muscae, a mind-controlling fungal parasite, proved a turning point.

It allowed Elya to closely study how the parasite turns the insects into zombies — and potentially glean more clues into how microbes can affect behavior, a topic that has garnered more popular interest recently with the rise in literature on the human gut biome. (Zombies of various stripes, on the other hand, have been of interest for centuries.)

Elya, who is now a postdoctoral researcher in the Department of Organismic and Evolutionary Biology, recently published some findings from her research in a preprint in bioRχiv.

When she made her discovery, Elya was trying to capture wild fruit flies in her yard for experiments, using rotting fruit as bait. One day, she found some dead flies in a striking pose, with their wings up. Looking more closely, she noticed they also had some material with a banding pattern on their abdomens.

Life | Work is a series focused on the personal side of Harvard research and teaching.

When Ju Chulakadabba was in elementary school in Thailand, she learned that industrial emissions are one important way that humans are changing the global climate. That’s when she realized that trying to make a difference wouldn’t necessarily be a far-off concern in her case, but a family matter.

Chulakadabba, a Ph.D. student in environmental science and engineering at the Harvard Kenneth C. Griffin Graduate School of Arts and Sciences and the John A. Paulson School of Engineering and Applied Sciences, grew up next door to a palm oil refinery on the outskirts of Bangkok. The factory, which employs more than 100 workers, was owned by her grandparents and remains a family business. Chulakadabba grew up surrounded by extended family — she’s the youngest of eight cousins — and remembers playing inside the factory in a large pile of clay used to transform the naturally reddish palm oil to the clear yellow liquid used in a dizzying array of prepared food, cosmetics, and consumer products throughout the world.

Chulakadabba never worked there — her mother became a psychiatrist instead of entering the family business — but she does plan to return and apply her education in environmental engineering to help make the facility more sustainable. In the meantime, she’s fostered her interest in the environment during undergraduate work at the Massachusetts Institute of Technology, and most recently in the lab of Steven Wofsy, Harvard’s Abbott Lawrence Rotch Professor of Atmospheric and Environmental Science.

“I feel like my family is a part of the issue,” Chulakadabba said. “I want to do something.”

That desire had her flying around the skies near Colorado last fall in a Gulfstream V jet mounted with methane-sensing instruments. The eight-hour flight acted as something of a proving ground for a project, called MethaneAIR, which will send the jet flying around the country later this year mapping sources of methane, a greenhouse gas much more potent than carbon dioxide. The flight also tested instruments and algorithms for a second, more ambitious project called MethaneSAT. MethaneSAT has a similar goal except, instead of a plane, the platform is a satellite — expected to launch in late 2023 or early 2024 — and the hunt for methane sources will be global rather than national.

“My family benefited from the factory. I have a good education because of it, so I want to return and do something good.”

Cephalopods such as octopus and squid evolutionarily diverged from mollusks like slugs and snails. These animals have elaborate compact nervous systems located within specialized arm appendages, which can perform a surprisingly diverse group of behaviors.

So how did these animals evolve neurologically from the shelled mollusk to a behaviorally sophisticated creature?

In two separate studies published in Nature, researchers from the Bellono lab at Harvard and Ryan Hibbs’ lab at UC San Diego discovered some clues, focusing on how cephalopod nervous systems adapt to sense their marine environments. They describe how the animals evolved using a family of chemotactile receptors within their arms and offer a glimpse into how such functional changes likely took place as adaptations to environment over deep evolutionary time.