Science

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A single peptide helps starfish get rid of a limb when attacked

biochemistry, Biology, muscles, Science, signaling, Starfish / /

You can have it —

A signaling molecule that’s so potent injected animals may drop more than one limb.

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A five-armed starfish, with orange and yellow colors, stretched out across a coral.

For many creatures, having a limb caught in a predator’s mouth is usually a death sentence. Not starfish, though—they can detach the limb and leave the predator something to chew on while they crawl away. But how can they pull this off?

Starfish and some other animals (including lizards and salamanders) are capable of autonomy (shedding a limb when attacked). The biology behind this phenomenon in starfish was largely unknown until now. An international team of researchers led by Maurice Elphick, professor of Animal Physiology and Neuroscience at Queen Mary University of London, have found that a neurohormone released by starfish is largely responsible for detaching limbs that end up in a predator’s jaws.

So how does this neurohormone (specifically a neuropeptide) let the starfish get away? When a starfish is under stress from a predatory attack, this hormone is secreted, stimulating a muscle at the base of the animal’s arm that allows the arm to break off.

The researchers confirmed this neuropeptide “acts as an autotomy-promoting factor in starfish and such it is the first neuropeptide to be identified as a regulator of autotomy in animals,” as they said in a study recently published in Current Biology.

Holding on

Elphick’s team studied how the neuropeptide known as ArSK/CCK1 facilitates autonomy in the European Starfish, Asterias rubens. ArSK/CCK1 is already known to inhibit feeding behavior in A. rubens by causing the stomach to contract, and muscle contraction plays a role in limb loss. The researchers found that its ability to trigger contractions goes beyond feeding.

Starfish underwent an experiment that simulated conditions where a predator’s jaw clamped down on one arm. Clamps were placed on one of three sections on a single arm, either on the end, middle, or at the site in the base where autotomy is known to occur, also known as the autotomy plane. The starfish were then suspended by these clamps above a glass bowl of seawater. During the first part of the experiment, the starfish were left to react naturally, but during the second part, they were injected with ArSK/CCK1.

Without the injection, autotomy was seen mostly in animals that had arms that were clamped closest to the autotomy plane. There was not nearly as much of a reaction from starfish when the arms were clamped in the middle or end.

In the second half of the experiment, the clamping used before was combined with an injection of ArSK/CCK1. For comparison, some were injected with the related neuropeptide ArSK/CCK2. A staggering 85 percent of ArSK/CCK1-injected animals that were clamped in the middle of the arm or closer to the autotomy plane exhibited autonomy, and some autotomized additional arms. This only happened in about 27 percent of those injected with ArSK/CCK2.

Letting go

While ArSK/CCK1 proved to be the most effective chemical trigger for autotomy, its activity in the autotomy plane depends on certain aspects of a starfish’s anatomy.

Like all echinoderms, starfish have endoskeletons built of tiny bones, or ossicles, linked by muscles and collagen fibers that allow the animals to change posture and move. Two exclusive features only found in the autotomy plane allow this structure to break. Under the skin of the autotomy plane, there is a region where bundles of collagen fibers are positioned far apart to make breakage easier. The second of these features is a band of muscle close to the region of collagen bundles. Known as the tourniquet muscle, this muscle is responsible for the constriction that allows an arm in danger to fall off.

Analyzing starfish arm tissue while it was undergoing autotomy gave the scientists a new perspective on this process. Right after a starfish has its arm seized by a predator,  ArSK/CCK1 tells nerves in the tourniquet muscle to start constricting in the region right by the autonomy plane. While this is happening, the collagen in the body wall in that region softens and breaks, and so do the muscles and ligaments that hold together ossicles. It is now thought that ArSK/CCK1 is also involved in the softening of this tissue that prepares it for breakage.

After starfish autotomize a limb, that limb eventually regenerates. The same happens in other animals that can use autotomy to their advantage (such as lizards, which also grow their tails back). In the future, finding out why some animals have the ability to regenerate may tell us why we either never evolved it or some of our ancestors lost the ability. Elphick acknowledged that there might still be other unidentified factors working together with ArSK/CCK1, but further insight could someday give us a clearer picture of this process.

“Autotomy is a key adaptation for survival that has evolved in several animal taxa,” the research team said in the same study, “[and] the findings of this study provide a seminal insight into the neural mechanisms that control this remarkable biological process,”

Current Biology, 2024.  DOI: 10.1016/j.cub.2024.08.003

A single peptide helps starfish get rid of a limb when attacked Read More »

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Navy captains don’t like abandoning ship—but with Starliner, the ship left them

Boeing, commercial crew, Commercial space, international space station, NASA, Science, Space, starliner / /
NASA astronauts Butch Wilmore and Suni Williams wave to their families, friends, and NASA officials on their way to the launch pad June 5 to board Boeing's Starliner spacecraft.

Enlarge / NASA astronauts Butch Wilmore and Suni Williams wave to their families, friends, and NASA officials on their way to the launch pad June 5 to board Boeing’s Starliner spacecraft.

NASA astronauts Butch Wilmore and Suni Williams are no strangers to time away from their families. Both are retired captains in the US Navy, served in war zones, and are veterans of previous six-month stays on the International Space Station.

When they launched to the space station on Boeing’s Starliner spacecraft on June 5, the astronauts expected to be home in a few weeks, or perhaps a month, at most. Their minimum mission duration was eight days, but NASA was always likely to approve a short extension. Wilmore and Williams were the first astronauts to soar into orbit on Boeing’s Starliner spacecraft, a milestone achieved some seven years later than originally envisioned by Boeing and NASA.

However, the test flight fell short of all of its objectives. Wilmore and Williams are now a little more than three months into what has become an eight-month mission on the station. The Starliner spacecraft was beset by problems, culminating in a decision last month by NASA officials to send the capsules back to Earth without the two astronauts. Rather than coming home on Starliner, Wilmore and Williams will return to Earth in February on a SpaceX Dragon spacecraft.

Grateful for options

On Friday, the two astronauts spoke with reporters for the first time since NASA decided they would stay in orbit until early 2025.

“It was trying at times,” Wilmore said. There were some tough times all the way through. Certainly, as the commander or pilot of your spacecraft, you don’t want to see it go off without you, but that’s where we wound up.”

Both astronauts are veteran Navy test pilots and have previous flights on space shuttles and Russian Soyuz spacecraft. Captains never want to abandon ship, but that’s not what happened with Starliner. Instead, their ship left them.

Williams said she and Wilmore watched Starliner’s departure from the space station from the lab’s multi-window cupola module last week. They kept busy with several tasks, such as monitoring the undocking and managing the space station’s systems during the dynamic phase of the departure.

“We were watching our spaceship fly away at that point in time,” Williams said. “I think it’s good we had some extra activities. Of course, we’re very knowledgeable about Starliner, so it was obvious what was happening at each moment.”

NASA’s top managers did not have enough confidence in Starliner’s safety after five thrusters temporarily failed as the spacecraft approached the space station in June. They weren’t ready to risk the lives of the two astronauts on Starliner when engineers weren’t convinced the same thrusters, or more, would function as needed during the trip home.

It turned out the suspect thrusters on Starliner worked after it departed the space station and headed for reentry on September 6. One thruster on Starliner’s crew module—different in design from the thrusters that previously had trouble—failed on the return journey. Investigating this issue is something Boeing and NASA engineers will add to their to-do list before the next Starliner flight, alongside the earlier problems of overheating thrusters and helium leaks.

“It’s a very risky business, and things do not always turn out the way you want,” Wilmore said. “Every single test flight, especially a first flight of a spacecraft or aircraft that’s ever occurred, has found issues …  90 percent of our training is preparing for the unexpected, and sometimes the actual unexpected goes beyond what you even think that could happen.”

Navy captains don’t like abandoning ship—but with Starliner, the ship left them Read More »

remembering-where-your-meals-came-from-key-for-a-small-bird’s-survival

Remembering where your meals came from key for a small bird’s survival

animal intelligence, Behavioral science, Biology, evolution, Science / /

Where’d I leave that again? —

For small birds, remembering where the food is beats forgetting when it’s gone.

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a small, black and grey bird perched on the branch of a fir tree.

It seems like common sense that being smart should increase the chances of survival in wild animals. Yet for a long time, scientists couldn’t demonstrate that because it was unclear how to tell exactly if a lion or a crocodile or a mountain chickadee was actually smart or not. Our best shots, so far, were looking at indirect metrics like brain size or doing lab tests of various cognitive skills such as reversal learning, an ability that can help an animal adapt to a changing environment.

But a new, large-scale study on wild mountain chickadees, led by Joseph Welklin, an evolutionary biologist at the University of Nevada, showed that neither brain size nor reversal learning skills were correlated with survival. What mattered most for chickadees, small birds that save stashes of food, was simply remembering where they cached all their food. A chickadee didn’t need to be a genius to survive; it just needed to be good at its job.

Testing bird brains

“Chickadees cache one food item in one location, and they do this across a big area. They can have tens of thousands of caches. They do this in the fall and then, in the winter, they use a special kind of spatial memory to find those caches and retrieve the food. They are little birds, weight is like 12 grams, and they need to eat almost all the time. If they don’t eat for a few hours, they die,” explains Vladimir Pravosudov, an ornithologist at the University of Nevada and senior co-author of the study.

The team chose the chickadees to study the impact cognitive skills had on survival because the failure to find their caches was their most common cause of death. This way, the team hoped, the impact of other factors like predation or disease would be minimized.

First, however, Welklin and his colleagues had to come up with a way to test cognitive skills in a fairly large population of chickadees. They did it by placing a metal square with two smart feeders attached to each side among the trees where the chickadees lived. “The feeders were equipped with RFID receivers that recognized the signal whenever a chickadee, previously marked with a microchip-fitted leg band, landed near them and opened the doors to dispense a single seed,” Welklin says. After a few days spent getting the chickadees familiar with the door-opening mechanism, the team started running tests.

The first task was aimed at testing how good different chickadees were at their most important job: associating a location with food and remembering where it was. To this end, each of the 227 chickadees participating in the study was assigned just one feeder that opened when they landed on it; all the other feeders remained closed. A chickadee’s performance was measured by the number of trials it needed to figure out which feeder would serve it, and how many errors (landings on the wrong feeders) it made over four days. “If you were to find the right feeder at random, it should take you 3.5 trials on average. All the birds learned and performed way better than chance,” Pravosudov says.

The second task was meant to test reversal learning skills, widely considered the best predictor of survival. Once the chickadees learned the location of the reward-dispensing feeders, the locations were changed. The goal was to see how fast the birds would adapt to this change.

Once the results of both tests were in, the team monitored the birds using their microchip bands, catching them and changing the bands every year, for over six years. “Part of the reason that’s never been done in the past is just because it takes so much work,” says Welklin. But the work paid off in the end.

Remembering where your meals came from key for a small bird’s survival Read More »

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Rocket Report: China leaps into rocket reuse; 19 people are currently in orbit

blue origin, china, crew dragon, falcon 9, human spaceflight, isar aerospace, LandSpace, launch, new glenn, Polaris dawn, rocket report, russia, Science, soyuz, Space, spacex / /

Ascendant —

Launch startups in China and Europe are borrowing ideas and rhetoric from SpaceX.

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Landspace's reusable rocket test vehicle lifts off from the Jiuquan Satellite Launch Center on Wednesday, September 11, 2024.

Enlarge / Landspace’s reusable rocket test vehicle lifts off from the Jiuquan Satellite Launch Center on Wednesday, September 11, 2024.

Welcome to Edition 7.11 of the Rocket Report! Outside of companies owned by American billionaires, the most imminent advancements in reusable rockets are coming from China’s quasi-commercial launch industry. This industry is no longer nascent. After initially relying on solid-fueled rocket motors apparently derived from Chinese military missiles, China’s privately funded launch firms are testing larger launchers, with varying degrees of success, and now performing hop tests reminiscent of SpaceX’s Grasshopper and F9R Dev1 programs more than a decade ago.

As always, we welcome reader submissions. If you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

Landspace hops closer to a reusable rocket. Chinese private space startup Landspace has completed a 10-kilometer (33,000-foot) vertical takeoff and vertical landing test on its Zhuque-3 (ZQ-3) reusable rocket testbed, including a mid-flight engine reignition at near supersonic conditions, Aviation Week & Space Technology reports. The 18.3-meter (60-foot) vehicle took off from the Jiuquan launch base in northwestern China, ascended to 10,002 meters, and then made a vertical descent and achieved an on-target propulsive landing 3.2 kilometers (2 miles) from the launch pad. Notably, the rocket’s methane-fueled variable-thrust engine intentionally shutdown in flight, then reignited for descent, as engines would operate on future full-scale booster flybacks. The test booster used grid fins and cold gas thrusters to control itself when its main engine was dormant, according to Landspace.

“All indicators met the expected design” … Landspace hailed the test as a major milestone in the company’s road to flying its next rocket, the Zhuque-3, as soon as next year. With nine methane-fueled main engines, the Zhuque-3 will initially be able to deliver 21 metric tons (46,300 pounds) of payload into low-Earth orbit with its booster flying in expendable mode. In 2026, Landspace aims to begin recovering Zhuque-3 first-stage boosters for reuse. Landspace is one of several Chinese companies working seriously on reusable rocket designs. Another Chinese firm, Deep Blue Aerospace, says it plans a 100-kilometer (62-mile) suborbital test of a reusable booster soon, ahead of the first flight of its medium-class Nebula-1 rocket next year. (submitted by Ken the Bin)

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Isar Aerospace sets low bar for success on first launch. Daniel Metzler, CEO of German launch startup Isar Aerospace, stated that the first flight of the Spectrum rocket would be a success if it didn’t destroy the launch site, European Spaceflight reports. During an interview at the Handelsblatt innovation conference, Metzler was asked what he would consider a successful inaugural flight of Spectrum. “For me, the first flight will be a success if we don’t blow up the launch site,” explained Metzler. “That would probably be the thing that would set us back the most in terms of technology and time.” This tempering of expectations sounds remarkably similar to statements made by Elon Musk about SpaceX’s first flight of the Starship rocket last year.

In the catbird seat? … Isar Aerospace could be in a position to become the first in a new crop of European commercial launch companies to attempt its first orbital flight. Another German company, Rocket Factory Augsburg, recently gave up on a possible launch this year after the booster for its first launch caught fire and collapsed during a test at a launch site in Scotland. Isar plans to launch its two-stage Spectrum rocket, designed to carry up to 1,000 kilograms (2,200 pounds) of payload into low-Earth orbit, from Andøya Spaceport in Norway. Isar hasn’t publicized any schedule for the first flight of Spectrum, but there are indications the publicity-shy company is testing hardware at the Norwegian spaceport. (submitted by Ken the Bin)

FAA to introduce new orbital debris rules. The Federal Aviation Administration is moving ahead with efforts to develop rules for the disposal of upper stages as another Centaur upper stage breaks apart in orbit, Space News reports. The FAA released draft regulations on the matter for public comment one year ago, and the head of the agency’s commercial spaceflight division recently said the rules are a “high priority for our organization.” The rules would direct launch operators to dispose of upper stages in one of five ways, from controlled reentries to placement in graveyard or “disposal” orbits not commonly used by operational satellites. One change the FAA might make to the draft rules is to reduce the required timeline for an uncontrolled reentry of a disposed upper stage from no more than 25 years to a shorter timeline. “We got a lot of comments that said it should be a lot less,” said Kelvin Coleman, head of the FAA’s commercial spaceflight office. “We’re taking that into consideration.”

Upper stages are a problem … Several recent breakups involving spent upper stages in orbit have highlighted the concern that dead rocket bodies could create unnecessary space junk. Last month, the upper stage from a Chinese Long March 6A disintegrated in low-Earth orbit, creating at least 300 pieces of space debris. More recently, a Centaur upper stage from a United Launch Alliance Atlas V rocket broke apart in a much higher orbit, resulting in more than 40 pieces of debris. This was the fourth time one of ULA’s Centaur upper stages has broken up since 2018. (submitted by Ken the Bin)

Rocket Report: China leaps into rocket reuse; 19 people are currently in orbit Read More »

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CEO of “health care terrorists” faces contempt charges after Senate no-show

contempt, hearing, hospitals, Science, Senate, steward, yacht / /

Horrific greed —

Senators are pursuing both civil and criminal contempt charges.

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The name placard for Dr. Ralph de la Torre, founder and chief executive officer of Steward Health Care System, in front of an empty seat during a Senate Health, Education, Labor, and Pensions Committee hearing in Washington, DC, on Thursday, September 12, 2024.

Enlarge / The name placard for Dr. Ralph de la Torre, founder and chief executive officer of Steward Health Care System, in front of an empty seat during a Senate Health, Education, Labor, and Pensions Committee hearing in Washington, DC, on Thursday, September 12, 2024.

The CEO of a failed hospital system who was paid hundreds of millions of dollars while patients were allegedly “killed and maimed” in his resource-starved and rotting facilities, was a no-show at a Senate hearing on Thursday—despite a bipartisan subpoena compelling him to appear.

Lawyers for Ralph de la Torre—the Harvard University-trained cardiac surgeon who took over the Steward Health Care System in 2020—told senators in a letter last week that he was unable to testify at the hearing. Despite previously agreeing to the hearing, de la Torre and his lawyers argued that a federal court order stemming from Steward’s bankruptcy case, filed in May, prevented him from discussing anything amid reorganization and settlement efforts.

But that argument was found to be without merit by the Senate committee that issued the subpoena in July—the Senate Committee on Health, Education, Labor, and Pensions (HELP), chaired by Bernie Sanders (I-Vt.). In comments to the Associated Press Wednesday, Sanders said there were plenty of topics he could have safely discussed.

“Tell me about your yacht”

“He has decided not to show up because he doesn’t want to explain to the American people how horrific his greed has become,” Sanders said. “Tell me about your yacht. Tell me about your fishing boat. I want to hear your justification for that. Tell that to the community where staff was laid off while you made $250 million.”

On Thursday, lawmakers prepared a seat for de la Torre at the hearing, but it stayed empty.

In a statement to ABC News Thursday, Steward defended de la Torre’s absence. “The Committee continues to ignore the fact that there is an ongoing settlement effort underway with all interested parties that paves the way to keep all of Steward’s remaining hospitals open and preserve jobs,” the statement said. “Dr. de la Torre will not do anything that could jeopardize this effort.”

Lawmakers, meanwhile, have moved forward with plans to pursue civil and criminal contempt of Congress charges. “A witness cannot disregard and evade a duly authorized subpoena,” ranking member Bill Cassidy (R-La.) said at today’s hearing. “Therefore, today, the chair and I will be asking the committee to report a resolution to authorize civil enforcement and criminal contempt proceedings against Dr. de la Torre requiring compliance with the subpoena.”  The committee has scheduled a session on Thursday, September 19, to adopt the two resolutions.

While the star witness was AWOL, the hearing moved on, offering stunning and horrifying testimony from two Massachusetts nurses and Louisiana state leaders who experienced the conditions at Steward’s hospitals, which number over 30 across eight states. The most heart-wrenching testimony came from Ellen MacInnis, a nurse at St. Elizabeth’s Medical Center in Boston, which was taken over by Steward.

CEO of “health care terrorists” faces contempt charges after Senate no-show Read More »

here’s-why-you-shouldn’t-freak-out-about-lead-in-your-cinnamon

Here’s why you shouldn’t freak out about lead in your cinnamon

cinnamon, health, lead, Science / /

A rant —

For the most part, you’d have to eat a weirdly large amount to cause a problem.

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Cinnamon buns.

Enlarge / Cinnamon buns.

Consumer Reports on Thursday reported the concentration of lead it found in 36 ground cinnamon products, leading to a round of startling headlines. The testing is particularly nerve-racking given that it closely follows the tragic poisoning of at least 519 US children, who were exposed to extremely high levels of lead from purposefully tainted cinnamon in applesauce snack pouches.

With that horrifying event in mind, parents are likely primed to be alarmed by any other lead findings in cinnamon. So, how concerning were the concentrations Consumer Reports found? And does one need to strictly adhere to the limits the organization recommends? By my calculations, not very and probably not. It’s really not an alarming report.

Similar to the outlet’s chocolate testing before it, the lead concentrations found in cinnamons were largely within standard ranges. In all, the report is more of a reminder that trace amounts of heavy metals are present in various common foods. And such watchdog testing can play a crucial role in keeping consumers safe, especially with underfunded and underpowered regulators.

Before I go into the data, I’ll be upfront with my conflict of interest here: I love cinnamon about as much as I love chocolate, which is to say: a lot. I can’t imagine fall or holidays without heavily cinnamoned treats. And if you believe that cinnamon isn’t a verb, you are incorrect (at least in my book). Still, my love of this tree-bark spice could certainly be shaken by my healthy aversion to neurotoxic things, especially with a small child at home gobbling up my baked goods. That’s why I dug in and did the math—and I’m happy to show my work.

Regulated concentrations

So, what did Consumer Reports (CR from here) find? The company collected three samples of each of the 36 products from grocery stores, specialty/international food shops, and online sellers. Then, they sent them off to a commercial lab for testing and reported back the average concentrations of lead in parts per million (ppm), which is equivalent to milligrams per kilogram (mg/kg).

CR judged the results by a threshold level of 1 ppm, which is the concentration at which the state of New York will issue a recall for a spice (currently, at least, they have proposed lowering it). It’s important to note that, even at the current 1 ppm threshold, New York is an outlier. As CR notes, New York is the only state to have such a threshold. The Food and Drug Administration doesn’t have a clear cut-off, but recent warnings from the agency were all regarding products that had lead concentrations of more than 2 ppm, not 1 ppm. The FDA also notes that the international food standard-setting body, Codex Alimentarius Commission, sets a limit for bark spices at 2.5 ppm. Further, the European Union set the maximum allowable lead concentration for bark spices at 2 ppm, according to regulations set in 2021 (PDF).

Despite the unusually low threshold, CR highlighted 12 products—mostly uncommon brands—that wouldn’t make it in the Big Apple. Of those, only three products were above the 2 ppm threshold that would have drawn the eyes of FDA and European Union regulators. The two brands behind the two highest readings (Paras at 3.52 ppm and EGN at 2.91 ppm) indicated to CR that they would voluntarily recall their products. The other product that came in above 2 ppm was Mimi’s Products cinnamon, with an average of 2.03 ppm. CR data shows that only one of the three samples was above 2 ppm (with readings of 1.97 ppm, 2.16 ppm, and 1.97 ppm).

That said, concentration thresholds for the purposes of regulatory recalls are one thing. Other things—likely to be far more relevant to consumers—are how much cinnamon people actually eat and what the maximum safe amount of lead is. So, what are those?

Here’s why you shouldn’t freak out about lead in your cinnamon Read More »

evidence-of-“snowball-earth”-found-in-ancient-rocks

Evidence of “snowball Earth” found in ancient rocks

climate, geology, Science, snowball earth / /

On ice —

An outcrop in Scotland has material from when the Earth went into a deep freeze.

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Image of a white planet with small patches of blue against a black background.

Enlarge / Artist’s conception of the state of the Earth during its global glaciations.

Earth has gone through many geologic phases, but it did have one striking period of stasis: Our planet experienced a tropical environment where algae and single-celled organisms flourished for almost 2 billion years. Then things changed drastically as the planet was plunged into a deep freeze.

It was previously unclear when Earth became a gargantuan freezer. Now, University College London researchers have found evidence in an outcrop of rocks in Scotland, known as the Port Askaig Formation, that show evidence of the transition from a tropical Earth to a frozen one 717 million years ago. This marks the onset of the Sturtian glaciation and would be the first of two “snowball Earth” events during which much of the planet’s surface was covered in ice. It is thought that multicellular life began to emerge after Earth thawed.

Found in the Scottish islands known as the Garvellachs, this outcrop within the Port Askaig Formation is unique because it offers the first conclusive evidence of when a tropical Earth froze over—underlying layers that are a timeline from a warmer era to a frigid one. Other rocks that formed during the same time period in other parts of the world lack this transitional evidence because ancient glaciers most likely scraped it off.

“The Port Askaig preserves a relatively complete record of the global “Sturtian glaciation,” the researchers said in a study recently published in the Journal of the Geological Society.

In my snowball era

Underneath the rocks that formed during the Sturtian glaciation is a deep layer of carbonate rocks known as the Garb Eileach Formation. These were dated to the warm, tropical Tonian period, which started 1 billion years ago and lasted until 717 million years ago, when the cold took over. The youngest rocks in this formation are evidence of the transition to the first “snowball Earth.”

Why did Earth endure such a big chill to begin with? A sudden decrease in solar radiation probably led to an especially long winter that set off a (if you’ll pardon the pun) snowball effect. With less radiation, more ice forms, and more ice makes the planet more reflective, meaning it sends more sunlight back into space and causes the planet to continue cooling, allowing even more ice to form.

To find out when this global chill began, the research team collected 11 sandstone samples from the Garvellach Islands to analyze zircons in the sandstone. Zircons are especially useful in dating rock formations because they are often as old as the rock they are in, making some of them the oldest minerals on Earth. They also resist being chemically degraded. What is especially important about zircons is that they contain uranium, which decays into lead over long periods. The amount of uranium that has changed to lead can tell us the amount of time that has passed since the zircon’s formation.

Just a phase

Using both laser ablation (a type of laser imaging that reveals how elements and isotopes are distributed in a sample) and plasma mass spectrometry, the researchers determined the uranium-lead ratio. The time it had taken for the uranium to become lead was in line with their estimates, which were based on previous studies that had estimated, but not confirmed, the time of onset for the Sturtian glaciation.

Another thing that the outcrop’s zircons told the researchers is that the Sturtian glaciation lasted around 58 million years. It was closely followed by the Marinoan glaciation, thought to have lasted another 16 million years, and both these “snowball Earth” phases make up what is known as the Cryogenic period. The rocks containing these zircons were probably deposited by a moving glacier as the supercontinent Rodinia (which preceded the more famous Pangaea) was breaking apart.

The Port Askaig Formation is now, as the scientists say in the same study, “one of the thickest (up to 1.1 km) and most complete records of Cryogenic glaciation.”

Because glaciers did not scrape this formation away, a record of when Earth started to warm up again is also preserved. The zircon crystals that formed during the Sturtian glaciation gradually disappear in younger rocks until they are replaced by zircons formed after the ice began to melt. So not only is there evidence of the beginning of the deep freeze, but also evidence for the thaw that began around 635 million years ago.

As the ice melted, complex multicellular life began to burst onto the scene during the Ediacaran period. There could be several reasons for this. Hypotheses suggest that the temperature of the seawater rose, an influx of sunlight sparked photosynthesis, and there was a greater availability of nutrients than before.

The scientists involved in the Port Askaig study think that any life that survived the Cryogenian period faced an immense challenge once the ice began to melt. These organisms had been used to perpetual cold for millions of years, and now they faced the struggle of adapting as soon as possible—or perishing.

What about those that survived? They ended up being the ancestors of all animals that ever existed, and that includes us.

Journal of the Geological Society, 2024.  DOI: 10.1144/jgs2024-02

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Meet the winners of the 2024 Ig Nobel Prizes

Features, Ig Nobel Prizes, Science / /

Science that makes you laugh then think —

The award ceremony features miniature operas, scientific demos, and the 24/7 lectures.

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The Ig Nobel Prizes honor

Enlarge / The Ig Nobel Prizes honor “achievements that first make people laugh and then make them think.”

Aurich Lawson / Getty Images

Curiosity is the driving force behind all science, which may explain why so many scientists sometimes find themselves going in some decidedly eccentric research directions. Did you hear about the WWII plan to train pigeons as missile guidance systems? How about experiments on the swimming ability of a dead rainbow trout or that time biologists tried to startle cows by popping paper bags by their heads? These and other unusual research endeavors were honored tonight in a virtual ceremony to announce the 2024 recipients of the annual Ig Nobel Prizes. Yes, it’s that time of year again, when the serious and the silly converge—for science.

Established in 1991, the Ig Nobels are a good-natured parody of the Nobel Prizes; they honor “achievements that first make people laugh and then make them think.” The unapologetically campy awards ceremony features miniature operas, scientific demos, and the 24/7 lectures whereby experts must explain their work twice: once in 24 seconds and the second in just seven words. Acceptance speeches are limited to 60 seconds. And as the motto implies, the research being honored might seem ridiculous at first glance, but that doesn’t mean it’s devoid of scientific merit.

Viewers can tune in for the usual 24/7 lectures, as well as the premiere of a “non-opera” featuring various songs about water, in keeping with the evening’s theme. In the weeks following the ceremony, the winners will also give free public talks, which will be posted on the Improbable Research website.

Without further ado, here are the winners of the 2023 Ig Nobel prizes.

Peace

Citation: B.F. Skinner, for experiments to see the feasibility of housing live pigeons inside missiles to guide the flight paths of the missiles.

This entertaining 1960 paper by American psychologist B.F. Skinner is kind of a personal memoir relating “the history of a crackpot idea, born on the wrong side of the tracks intellectually speaking but eventually vindicated in a sort of middle class respectability.” Project Pigeon was a World War II research program at the Naval Research Laboratory with the objective of training pigeons to serve as missile guidance systems. At the time, in the early 1940s, the machinery required to guide Pelican missiles was so bulky that there wasn’t much room left for actual explosives—hence the name, since it resembled a pelican “whose beak can hold more than its belly can.”

Skinner reasoned that pigeons could be a cheaper, more compact solution since the birds are especially good at responding to patterns. (He dismissed the ethical questions as a “peacetime luxury,” given the high global stakes of WWII.) His lab devised a novel harnessing system for the birds, positioned them vertically above a translucent plastic plate (screen), and trained them to “peck” at a projected image of a target somewhere along the New Jersey coast on the screen—a camera obscura effect. “The guiding signal was picked up from the point of contact of screen and beak,” Skinner wrote. Eventually, they created a version that used three pigeons to make the system more robust—just in case a pigeon got distracted at a key moment or something.

Nose cone of NIST glide bomb showing the three-pigeon guidance system.

Enlarge / Nose cone of NIST glide bomb showing the three-pigeon guidance system.

American Psychological Association/B.F. Skinner Foundation

There was understandably a great deal of skepticism about the viability of using pigeons for missile guidance; at one point, Skinner lamented, his team “realized that a pigeon was more easily controlled than a physical scientist serving on a committee.” But Skinner’s team persisted, and in 1944, they finally got the chance to demonstrate Project Pigeon for a committee of top scientists and show that the birds’ behavior could be controlled. The sample pigeon behaved perfectly. “But the spectacle of a living pigeon carrying out its assignment, no matter how beautifully, simply reminded the committee of how utterly fantastic our proposal was.” Apparently, there was much “restrained merriment.”

Even though this novel homing device was resistant to jamming, could react to a wide variety of target practice, needed no scarce materials, and was so simple to make that production could start in 30 days, the committee nixed the project. (By this point, as we now know, military focus had shifted to the Manhattan Project.) Skinner was left with “a loftful of curiously useless equipment and a few dozen pigeons with a strange interest in a feature of the New Jersey coast.” But vindication came in the early 1950s when the project was briefly revived as Project ORCON at the Naval Research Laboratory, which refined the general idea and led to the development of a Pick-off Display Converter for radar operators. Skinner himself never lost faith in this particular “crackpot idea.”

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Court clears researchers of defamation for identifying manipulated data

defamation, lawsuit, Policy, Science, Scientific Misconduct / /

Evidence-supported conclusions aren’t defamation —

Harvard, however, will still face trial over how it managed the investigation.

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A formal red brick building on a college campus.

Enlarge / Harvard Business School was targeted by a faculty member’s lawsuit.

Earlier this year, we got a look at something unusual: the results of an internal investigation conducted by Harvard Business School that concluded one of its star faculty members had committed research misconduct. Normally, these reports are kept confidential, leaving questions regarding the methods and extent of data manipulations.

But in this case, the report became public because the researcher had filed a lawsuit that alleged defamation on the part of the team of data detectives that had first identified potential cases of fabricated data, as well as Harvard Business School itself. Now, the court has ruled on motions to dismiss the case. While the suit against Harvard will go on, the court has ruled that evidence-backed conclusions regarding fabricated data cannot constitute defamation—which is probably a very good thing for science.

Data and defamation

The researchers who had been sued, Uri Simonsohn, Leif Nelson, and Joe Simmons, run a blog called Data Colada where, among other things, they note cases of suspicious-looking data in the behavioral sciences. As we detailed in our earlier coverage, they published a series of blog posts describing an apparent case of fabricated data in four different papers published by the high-profile researcher Francesca Gino, a professor at Harvard Business School.

The researchers also submitted the evidence to Harvard, which ran its own investigation that included interviewing the researchers involved and examining many of the original data files behind the paper. In the end, Harvard determined that research misconduct had been committed, placed Gino on administrative leave and considered revoking her tenure. Harvard contacted the journals where the papers were published to inform them that the underlying data was unreliable.

Gino then filed suit alleging that Harvard had breached their contract with her, defamed her, and interfered with her relationship with the publisher of her books. She also added defamation accusations against the Data Colada team. Both Harvard and the Data Colada collective filed a motion to have all the actions dismissed, which brings us to this new decision.

Harvard got a mixed outcome. This appears to largely be the result that the Harvard Business School adopted a new and temporary policy for addressing research misconduct when the accusations against Gino came in. This, according to the court, leaves questions regarding whether the university had breached its contract with her.

However, most of the rest of the suit was dismissed. The judge ruled that the university informing Gino’s colleagues that Gino had been placed on administrative leave does not constitute defamation. Nor do the notices requesting retractions sent to the journals where the papers were published. “I find the Retraction Notices amount ‘only to a statement of [Harvard Business School]’s evolving, subjective view or interpretation of its investigation into inaccuracies in certain [data] contained in the articles,’ rather than defamation,” the judge decided.

Colada in the clear

More critically, the researchers had every allegation against them thrown out. Here, the fact that the accusations involved evidence-based conclusions, and were presented with typical scientific caution, ended up protecting the researchers.

The court cites precedent to note that “[s]cientific controversies must be settled by the methods of science rather than by the methods of litigation” and concludes that the material sent to Harvard “constitutes the Data Colada Defendants’ subjective interpretation of the facts available to them.” Since it had already been determined that Gino was a public figure due to her high-profile academic career, this does not rise to the standard of defamation.

And, while the Data Colada team was pretty definitive in determining that data manipulation had taken place, its members were cautious about acknowledging that the evidence they had did not clearly indicate Gino was the one who had performed the manipulation.

Finally, it was striking that the researchers had protected themselves by providing links to the data sources they’d used to draw their conclusions. The decision cites a precedent that indicates “by providing hyperlinks to the relevant information, the articles enable readers to review the underlying information for themselves and reach their own conclusions.”

So, overall, it appears that, by couching their accusations in the cautious language typical of scientific writing, the researchers ended up protecting themselves from accusations of defamation.

That’s an important message for scientists in general. One of the striking developments of the last few years has been the development of online communities where scientists identify and discuss instances of image and data manipulation, some of which have ultimately resulted in retractions and other career consequences. Every now and again, these activities have resulted in threats of lawsuits against these researchers or journalists who report on the issue. Occasionally, suits get filed.

Ultimately, it’s probably good for the scientific record that these suits are unlikely to succeed.

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AI chatbots might be better at swaying conspiracy theorists than humans

AI, ai chatbots, conspiracy theories, large langauge models, psychology, Science / /

Out of the rabbit hole —

Co-author Gordon Pennycook: “The work overturns a lot of how we thought about conspiracies.”

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A woman wearing a sweatshirt for the QAnon conspiracy theory on October 11, 2020 in Ronkonkoma, New York.

Enlarge / A woman wearing a sweatshirt for the QAnon conspiracy theory on October 11, 2020 in Ronkonkoma, New York.

Stephanie Keith | Getty Images

Belief in conspiracy theories is rampant, particularly in the US, where some estimates suggest as much as 50 percent of the population believes in at least one outlandish claim. And those beliefs are notoriously difficult to debunk. Challenge a committed conspiracy theorist with facts and evidence, and they’ll usually just double down—a phenomenon psychologists usually attribute to motivated reasoning, i.e., a biased way of processing information.

A new paper published in the journal Science is challenging that conventional wisdom, however. Experiments in which an AI chatbot engaged in conversations with people who believed at least one conspiracy theory showed that the interaction significantly reduced the strength of those beliefs, even two months later. The secret to its success: the chatbot, with its access to vast amounts of information across an enormous range of topics, could precisely tailor its counterarguments to each individual.

“These are some of the most fascinating results I’ve ever seen,” co-author Gordon Pennycook, a psychologist at Cornell University, said during a media briefing. “The work overturns a lot of how we thought about conspiracies, that they’re the result of various psychological motives and needs. [Participants] were remarkably responsive to evidence. There’s been a lot of ink spilled about being in a post-truth world. It’s really validating to know that evidence does matter. We can act in a more adaptive way using this new technology to get good evidence in front of people that is specifically relevant to what they think, so it’s a much more powerful approach.”

When confronted with facts that challenge a deeply entrenched belief, people will often seek to preserve it rather than update their priors (in Bayesian-speak) in light of the new evidence. So there has been a good deal of pessimism lately about ever reaching those who have plunged deep down the rabbit hole of conspiracy theories, which are notoriously persistent and “pose a serious threat to democratic societies,” per the authors. Pennycook and his fellow co-authors devised an alternative explanation for that stubborn persistence of belief.

Bespoke counter-arguments

The issue is that “conspiracy theories just vary a lot from person to person,” said co-author Thomas Costello, a psychologist at American University who is also affiliated with MIT. “They’re quite heterogeneous. People believe a wide range of them and the specific evidence that people use to support even a single conspiracy may differ from one person to another. So debunking attempts where you try to argue broadly against a conspiracy theory are not going to be effective because people have different versions of that conspiracy in their heads.”

By contrast, an AI chatbot would be able to tailor debunking efforts to those different versions of a conspiracy. So in theory a chatbot might prove more effective in swaying someone from their pet conspiracy theory.

To test their hypothesis, the team conducted a series of experiments with 2,190 participants who believed in one or more conspiracy theories. The participants engaged in several personal “conversations” with a large language model (GT-4 Turbo) in which they shared their pet conspiracy theory and the evidence they felt supported that belief. The LLM would respond by offering factual and evidence-based counter-arguments tailored to the individual participant. GPT-4 Turbo’s responses were professionally fact-checked, which showed that 99.2 percent of the claims it made were true, with just 0.8 percent being labeled misleading, and zero as false. (You can try your hand at interacting with the debunking chatbot here.)

Screenshot of the chatbot opening page asking questions to prepare for a conversation

Enlarge / Screenshot of the chatbot opening page asking questions to prepare for a conversation

Thomas H. Costello

Participants first answered a series of open-ended questions about the conspiracy theories they strongly believed and the evidence they relied upon to support those beliefs. The AI then produced a single-sentence summary of each belief, for example, “9/11 was an inside job because X, Y, and Z.” Participants would rate the accuracy of that statement in terms of their own beliefs and then filled out a questionnaire about other conspiracies, their attitude toward trusted experts, AI, other people in society, and so forth.

Then it was time for the one-on-one dialogues with the chatbot, which the team programmed to be as persuasive as possible. The chatbot had also been fed the open-ended responses of the participants, which made it better to tailor its counter-arguments individually. For example, if someone thought 9/11 was an inside job and cited as evidence the fact that jet fuel doesn’t burn hot enough to melt steel, the chatbot might counter with, say, the NIST report showing that steel loses its strength at much lower temperatures, sufficient to weaken the towers’ structures so that it collapsed. Someone who thought 9/11 was an inside job and cited demolitions as evidence would get a different response tailored to that.

Participants then answered the same set of questions after their dialogues with the chatbot, which lasted about eight minutes on average. Costello et al. found that these targeted dialogues resulted in a 20 percent decrease in the participants’ misinformed beliefs—a reduction that persisted even two months later when participants were evaluated again.

As Bence Bago (Tilburg University) and Jean-Francois Bonnefon (CNRS, Toulouse, France) noted in an accompanying perspective, this is a substantial effect compared to the 1 to 6 percent drop in beliefs achieved by other interventions. They also deemed the persistence of the effect noteworthy, while cautioning that two months is “insufficient to completely eliminate misinformed conspiracy beliefs.”

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In abortion ban states, sterilization spiked after Dobbs and kept climbing

Abortion, contraception, health, JAMA, maternity, reproductive health, Science, sterlization, women's health / /

Can’t blame ’em —

Sterilizations spike with abortion bans and declining access to care and contraception.

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A woman holds a placard saying

Enlarge / A woman holds a placard saying “No Forced Births” as abortion rights activists gather at the Monroe County Courthouse for a protest vigil a few hours before Indianas near total abortion ban goes into effect on September 15, 2022.

The more abortion access is jeopardized, the more women turn to sterilization, according to a new report in JAMA that drew on health insurance claims of nearly 4.8 million women in the US.

In states that enacted total or near-total abortion bans following the US Supreme Court’s Dobbs decision in June 2022, the rate of sterilizations among reproductive-age women that July spiked 19 percent. A similar initial spike was seen across the nation, with states that either limited or protected access to abortions seeing a 17 percent increase.

But, after that, states with bans saw a divergent trend. The states that limited or protected abortion access saw sterilization procedures largely level off after July 2022. In contrast, states with bans continued to see increases. From July 2022 to December 2022, use of sterilization procedures increased by 3 percent each month.

The study adds to previous data finding that overturning Roe v. Wade and limiting legal access to abortion spurred reproductive-age people to seek permanent contraception. A study published in JAMA Health Forum in April, for instance, found an abrupt increase in tubal ligation and vasectomies in people aged 18 to 30 shortly after the Dobbs decision. The current study furthers the finding by assessing trends of sterilization procedures in the context of state abortion laws and policies.

The surge in sterilization is just one of the many ways reproductive healthcare in the US has been rocked or upended by the Supreme Court’s 2022 decision. In June, a study in JAMA Network Open found that states with the most restrictive abortion policies saw declines in prescriptions filled for birth control pills and emergency contraception. The finding suggests that the abortion bans and limitations have disrupted and created barriers to contraception access in restrictive states.

On Tuesday, meanwhile, the March of Dimes released a report painting a bleak picture for Americans who become pregnant. The analysis found that over half of US counties do not have a hospital that provides obstetric care. In the last two years, 1 in 25 obstetric units shut down. Further, 35 percent of counties in the US are considered maternity deserts, meaning that 1,104 counties in the US do not have a birthing facility or even a single obstetric clinician. Living in a maternity desert is associated with receiving less prenatal care and higher rates of preterm birth. Those 1,104 counties are home to 2.3 million women of reproductive age who gave birth to over 150,000 babies in 2022.

The US continues to have the highest rate of maternal deaths among any high-income country, with Black women seeing the highest death rates, according to the latest report from the Commonwealth Fund.

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Old Easter Island genomes show no sign of a population collapse

anthropology, Biology, easter island, evolution, human evolution, native americans, Polynesians, rapa nui, Science / /
A row of grey rock sculptures of human torsos and heads, arranged in a long line.

Rapa Nui, often referred to as Easter Island, is one of the most remote populated islands in the world. It’s so distant that Europeans didn’t stumble onto it until centuries after they had started exploring the Pacific. When they arrived, though, they found that the relatively small island supported a population of thousands, one that had built imposing monumental statues called moai. Arguments over how this population got there and what happened once it did have gone on ever since.

Some of these arguments, such as the idea that the island’s indigenous people had traveled there from South America, have since been put to rest. Genomes from people native to the island show that its original population was part of the Polynesian expansion across the Pacific. But others, such as the role of ecological collapse in limiting the island’s population and altering its culture, continue to be debated.

Researchers have now obtained genome sequence from the remains of 15 Rapa Nui natives who predate European contact. And they indicate that the population of the island appears to have grown slowly and steadily, without any sign of a bottleneck that could be associated with an ecological collapse. And roughly 10 percent of the genomes appear to have a Native American source that likely dates from roughly the same time that the island was settled.

Out of the museum

The remains that provided these genomes weren’t found on Rapa Nui, at least not recently. Instead, they reside at the Muséum National d’Histoire Naturelle in France, having been obtained at some uncertain point in the past. Their presence there is a point of contention for the indigenous people of Rapa Nui, but the researchers behind the new work had the cooperation of the islanders in this project, having worked with them extensively. The researchers’ description of these interactions could be viewed as a model for how this sort of work should be done:

Throughout the course of the study, we met with representatives of the Rapanui community on the island, the Comisión de Desarrollo Rapa Nui and the Comisión Asesora de Monumentos Nacionales, where we presented our research goals and ongoing results. Both commissions voted in favor of us continuing with the research… We presented the research project in public talks, a short video and radio interviews on the island, giving us the opportunity to inquire about the questions that are most relevant to the Rapanui community. These discussions have informed the research topics we investigated in this work.

Given the questionable record-keeping at various points in the past, one of the goals of this work was simply to determine whether these remains truly had originated on Rapa Nui. That was unambiguously true. All comparisons with genomes of modern populations show that all 15 of these genomes have a Polynesian origin and are most closely related to modern residents of Rapa Nui. “The confirmation of the origin of these individuals through genomic analyses will inform repatriation efforts led by the Rapa Nui Repatriation Program (Ka Haka Hoki Mai Te Mana Tupuna),” the authors suggest.

A second question was whether the remains predate European contact. The researchers attempted to perform carbon dating, but it produced dates that made no sense. Some of the remains had dates that were potentially after they had been collected, according to museum records. And all of them were from the 1800s, well after European contact and introduced diseases had shrunk the native population and mixed in DNA from non-Polynesians. Yet none of the genomes showed more than one percent European ancestry, a fraction low enough to be ascribed to a spurious statistical fluke.

So the precise date these individuals lived is uncertain. But the genetic data clearly indicates that they were born prior to the arrival of Europeans. They can therefore tell us about what the population was experiencing in the period between Rapa Nui’s settlement and the arrival of colonial powers.

Back from the Americas

While these genomes showed no sign of European ancestry, they were not fully Polynesian. Instead, roughly 10 percent of the genome appeared to be derived from a Native American population. This is the highest percentage seen in any Polynesian population, including some that show hints of Native American contact that dates to before Europeans arrived on the scene.

Isolating these DNA sequences and comparing them to populations from across the world showed that the group most closely related to the one who contributed to the Rapa Nui population presently resides in the central Andes region of South America. That’s in contrast to the earlier results, which suggested the contact was with populations further north in South America.

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