Extinct Caribbean bird's closest relatives hail from Africa, South Pacific

 In a genetic surprise, ancient DNA shows the closest family members of an extinct bird known as the Haitian cave-rail are not in the Americas, but Africa and the South Pacific, uncovering an unexpected link between Caribbean bird life and the Old World.

Like many animals unique to the Caribbean, cave-rails became extinct soon after people settled the islands. The last of three known West Indian species of cave-rails -- flightless, chicken-sized birds -- vanished within the past 1,000 years. Florida Museum of Natural History researchers sought to resolve the group's long-debated ancestry by analyzing DNA from a fossil toe bone of the Haitian cave-rail, Nesotrochis steganinos. But they were unprepared for the results: The genus Nesotrochis is most closely related to the flufftails, flying birds that live in sub-Saharan Africa, Madagascar and New Guinea, and the adzebills, large, extinct, flightless birds native to New Zealand.

The study presents the first example of a Caribbean bird whose closest relatives live in the Old World, showcasing the power of ancient DNA to reveal a history erased by humans.

The discovery was "just mind-blowing," said study lead author Jessica Oswald, who began the project as a postdoctoral researcher at the Florida Museum.

"If this study had not happened, we might still be under the assumption that the closest relatives of most things in the Caribbean are on the mainland in the Americas," said Oswald, now a postdoctoral researcher at the University of Nevada, Reno and a Florida Museum research affiliate. "This gives us an understanding of the region's biodiversity that would otherwise be obscured."

Many animals evolved unusual forms on islands, often making it difficult to classify extinct species based on their physical characteristics alone. But advancements in extracting viable DNA from fossils now enables scientists like Oswald to answer longstanding questions with ancient genetic evidence. Oswald described her work as similar to a forensic investigation, tracing the evolutionary backstory of extinct animals by piecing together fragmented, degraded genetic material.

"Understanding where all of these extinct species fit into a larger family tree or evolutionary history gives us insight into what a place looked like before people arrived," she said. "That's why my job is so fun. It's always this whodunit."

Oswald was just starting her ancient DNA work at the Florida Museum when David Steadman, curator of ornithology and study co-author, suggested the Haitian cave-rail as a good candidate for analysis.

Cave-rails share physical characteristics with several types of modern birds, and scientists have conjectured for decades whether they are most closely related to wood rails, coots or swamphens -- birds that all belong to the rail family, part of a larger group known as the Gruiformes. Oswald and Steadman hoped that studying cave-rail DNA would clarify "what the heck this thing is," Oswald said.

When preliminary results indicated the species had a trans-Atlantic connection, Steadman, who has worked in the Caribbean for more than 40 years, was skeptical.

The genetics also showed that the cave-rail isn't a rail at all: While flufftails and adzebills are also members of the Gruiformes, they are in separate families from rails.

"It just didn't seem logical that you'd have to go across the Atlantic to find the closest relative," Steadman said. "But the fact that people had a hard time classifying where Nesotrochis was within the rails -- in hindsight, maybe that should have been a clue. Now I have a much more open mind."

One reason the cave-rail was so difficult to classify is that when birds lose the ability to fly, they often converge on a similar body plan, Steadman said. Flightlessness is a common adaptation in island birds, which face far fewer predators in the absence of humans and invasive species such as dogs, cats, rats and pigs.

"You don't have to outfly or outrun predators, so your flying and running abilities become reduced," Steadman said. "Because island birds spend less energy avoiding predators, they also tend to have a lower metabolic rate and nest on the ground. It's no longer life in the fast lane. They're essentially living in a Corona commercial."

While sheltered from the mass extinctions that swept the mainland, cave-rails were helpless once people touched foot on the islands, having lost their defenses and cautiousness.

"Being flightless and plump was not a great strategy during human colonization of the Caribbean," said study co-author Robert Guralnick, Florida Museum curator of biodiversity informatics.

How did cave-rails get to the Caribbean in the first place? Monkeys and capybara-like rodents journeyed from Africa to the New World about 25-36 million years ago, likely by rafting, and cave-rails may also have migrated during that timespan, Steadman said. He and Oswald envision two probable scenarios: The ancestors of cave-rails either made a long-distance flight across an Atlantic Ocean that was not much narrower than today, or the group was once more widespread across the continents, with more relatives remaining to be discovered in the fossil record.

Other researchers have recently published findings that corroborate the story told by cave-rail DNA: A study of foot features suggested Nesotrochis could be more closely related to flufftails than rails, and other research showed that adzebills are close relatives of the flufftails. Like cave-rails, adzebills are also an example of a flightless island bird extinguished by human hunters.

"Humans have meddled so much in the region and caused so many extinctions, we need ancient DNA to help us sort out what's related to what," Oswald said.

The findings also underscore the value of museum collections, Steadman said. The toe bone Oswald used in her analysis was collected in 1983 by Charles Woods, then the Florida Museum's curator of mammals. At that time, "nobody was thinking about ancient DNA," Steadman said. "It shows the beauty of keeping things well curated in a museum."

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Substantially higher burden of COVID-19 compared to flu, new research shows

 In a paper published in the Journal of General Internal Medicine, physician-researchers at Beth Israel Deaconess Medical Center (BIDMC) assessed the relative impact of COVID-19 on patients hospitalized with the viral infection in March and April 2020, versus patients hospitalized with influenza during the last five flu seasons at the medical center. Overall, the team demonstrated that COVID-19 cases resulted in significantly more weekly hospitalizations, more use of mechanical ventilation and higher mortality rates than influenza.

COVID-19 and influenza are both contagious respiratory viral diseases that can lead to pneumonia and acute respiratory failure in severe cases. However, detailed comparison of the epidemiology and clinical characteristics of COVID-19 and those of influenza are lacking.

"COVID-19 has been compared to influenza both by health care professionals and the lay public, but there's really limited detailed objective data available for comparing and contrasting the impact of these two diseases on patients and hospitals," said corresponding author Michael Donnino, MD, Critical Care and Emergency Medicine physician at BIDMC. "We compared patients admitted to BIDMC with COVID-19 in spring 2020 to patients admitted to BIDMC with influenza during the last five flu seasons. We found that COVID-19 causes more severe disease and is more lethal than influenza."

Donnino and colleagues included a total of 1,634 hospitalized patients in their study, 582 of whom had laboratory-confirmed COVID-19 and 1,052 of whom had confirmed influenza. The team found that, on average, 210 patients were admitted to BIDMC during each eight-month flu season, compared to the 582 patients with COVID-19 admitted in March and April 2020. While 174 patients with COVID-19 (or 30 percent) received mechanical ventilation during the two-month period, just 84 patients with influenza (or 8 percent) were placed on ventilation over all five seasons of influenza. Likewise, the proportion of patients who died was much higher for COVID-19 than for influenza; 20 percent of admitted patients with COVID-19 died in the two-month period, compared to three percent of patients with influenza over five seasons.

Further analysis revealed that hospitalized patients with COVID-19 tended to be younger than those hospitalized with influenza. Among patients requiring mechanical ventilation, patients with COVID-19 were on ventilation much longer -- a median duration of two weeks -- compared to just over three days for patients with influenza. Moreover, among patients requiring mechanical ventilation, patients with COVID-19 were far less likely to have had pre-existing medical conditions.

"Our data illustrate that 98 percent of deaths of patients hospitalized with COVID-19 were directly or indirectly related to their COVID-19 illness, illustrating that patients did not die with COVID but rather from COVID pneumonia or a complication," said Donnino.

The authors note that the stringent social distancing guidance in effect last spring may have impacted these findings by limiting the incidence and lethality of COVID-19 toward the end of April 2020. Conversely, some treatment practices have evolved over the course of the pandemic, potentially improving outcomes for patients with COVID-19.

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How do humpback whales rest?

An international research collaboration has used an omnidirectional camera attached to humpback whale to reveal how these creatures rest underwater. These findings demonstrate how wide-angle lens cameras can be useful tools for illuminating the ecology of difficult-to-observe animals in detail.

The research group consisted of Assistant Professor Takashi Iwata of Kobe University's Graduate School of Maritime Sciences, Researcher Martin Biuw of the Norwegian Institute of Marine Research, Assistant Professor Kagari Aoki and Professor Katsufumi Sato of the Atmosphere and Ocean Research Institute, the University of Tokyo, and Professor Patrick Miller of the University of St. Andrews.

These research results were published online in Behavioural Processes on February 25, 2021.

Main Points
 

• The researchers attached an omnidirectional (360°) camera to a humpback whale and discovered that these animals rest while drifting underwater. Whales can rest either on the surface or underwater, and it is believed that they choose which of these different environments to rest in depending on the situation.
• The omnidirectional camera recorded a wide range of information on the environment surrounding the tagged whale, revealing that humpback whales rest in groups rather than on their own.
• These results have demonstrated that animal-borne omnidirectional cameras are useful for learning more about animals that are difficult to observe.

Research Background

It is difficult to observe the ecology of marine animals directly as they spend the majority of their lives underwater. However, studies on the ecology of difficult-to-observe marine animals have been recently conducted using a method called bio-logging. This method involves attaching a camera to an animal and recording environmental information related to their behavior and surroundings. Various kinds of data can be recorded and measured, and this information can be used to understand aspects such as animal behavior and diving physiology. Such data includes depth, swimming speed, acceleration (which can be used to understand the animal's posture and detailed movements), vocalizations, heart rate and GPS (Global Positioning System) location data.

Cameras in particular are a powerful tool as they enable researchers to view the individual animal's surroundings, which in turn helps them to understand the animal's behavior. However, the camera's limited field of view has been an issue with animal-borne cameras up until now. For example, research using a camera attached to a humpback whale (Megaptera novaeangliae) revealed that the whale would quickly move away from foraging sites if a competitor was present. However, the competitor was not visible due to the limited scope of the camera, therefore its presence was merely assumed. A camera with a wide-angle lens is therefore necessary to film the animal's entire surroundings.

This research focused on the humpback whale, a species of baleen whale that is found in oceans around the globe. Using bio-logging, researchers have learned more about humpback whales' foraging habits, however little is known about their resting behaviors. Foraging events can be identified from the recorded depth, swimming speed and acceleration (movement) of the whale that are characteristic signs that it is chasing prey. However, researchers have not identified the characteristic signs of resting, and it is not understood what the differences are between resting and swimming slowly. Information about an animal's resting behavior is necessary in order to understand their ecology. For example, if we consider animal behaviors in terms of their time budget, the percentage of time for other activities such as foraging decreases if their resting periods increase. Even though information about resting behaviors is essential for understanding animal ecology, hardly anything is known about baleen whales' resting habits.

This research group used an omnidirectional camera (with a 360° field-of-view on land and a 270° field-of-view underwater) and a behavioral data logger in order to illuminate the resting behavior of humpback whales.

Research Methodology and Findings

RICOH supplied the basic THETA camera module for this research, which was made pressure-resistant and waterproofed using epoxy glue by Little Leonardo Corp., leading to the development of a new type of animal-borne omnidirectional camera. A suction cup tag was made out of buoyant materials that could be attached to the whale. The tag contained an omnidirectional camera, a behavioral data logger and a radio transmitter.

The field study was conducted in January 2016, off the Tromsø coast in Norway. To tag the whale, the researchers approached it in a small vessel (5-6m) and used a 6m pole to attach the tag to the animal. The tag was designed so that it would fall off naturally after several hours and float up to the surface. The tag was then recovered by determining its location via the signal from the transmitter.

The research team were able to tag one individual, obtaining around one hour of video data and approximately eleven hours of behavioral data. From the behavioral data, the researchers discovered that the whale was inactive during the first half of the recorded period and demonstrated active behavior in the latter half.

Based on past research, it was assumed that this active movement in the latter half was foraging activity. The video data was captured during the first half of the behavioral data recording period when the whale did not move much. In this videoed period, the tagged whale's deepest dive was 11m on average and its average swimming speed (cruising speed) was 0.75m/s-1. It has been reported that humpback whales' regular swimming speed is 1.45m/s-1, however the tagged whale was moving much more slowly during this period. Whales usually move their flukes (tails) when they swim but there were no signs that the individual whale moved its fluke in the behavioral data recorded during the videoed period. In the footage, two other whales that are drifting underwater without moving their flukes are visible. It was determined that the tagged individual was also drifting underwater from its slow swimming speed, lack of fluke movement and the continued presence in the video footage of other individuals that were drifting. Seal species, sperm whales and loggerhead turtles are known to drift underwater while they are resting. Therefore, it is believed that the tagged humpback whale in this study was also resting. Previous research has reported that baleen whale species rest on the surface but this study has revealed that they also rest while drifting underwater. It is thought that whales consider factors such as marine conditions and their own physical condition when choosing from the two different resting environments: on the surface or underwater. In addition, the footage from the omnidirectional camera shows that whales rest underwater in a group rather than on their own.

Further Research

Researchers have been using animal-borne cameras as a tool to investigate the ecology of marine animals. For example, a backwards-facing camera attached to a mother seal recorded images of a pup swimming behind her. However, to ascertain the significance of these images (for example, whether or not the mother was teaching the pup how to hunt) it is necessary to use a camera with a wide field of view so that we can obtain knowledge about the surrounding environment. Still camera images of touching behaviors between whales have also been recorded; however, a wide-lens camera would aid researchers in determining the frequency at which this behavior occurs. These examples show how necessary wide-lens cameras, such as omnidirectional cameras, are for investigating the ecology of marine animals. Such cameras enable researchers to record the environment surrounding the tagged animal, enabling them to determine whether other individuals (such as competitors, collaborators, or predators) are present or not, and understand the frequency and distribution of food sources.

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When volcanoes go metal

 What would a volcano -- and its lava flows -- look like on a planetary body made primarily of metal? A pilot study from North Carolina State University offers insights into ferrovolcanism that could help scientists interpret landscape features on other worlds.

Volcanoes form when magma, which consists of the partially molten solids beneath a planet's surface, erupts. On Earth, that magma is mostly molten rock, composed largely of silica. But not every planetary body is made of rock -- some can be primarily icy or even metallic.

"Cryovolcanism is volcanic activity on icy worlds, and we've seen it happen on Saturn's moon Enceladus," says Arianna Soldati, assistant professor of marine, earth and atmospheric sciences at NC State and lead author of a paper describing the work. "But ferrovolcanism, volcanic activity on metallic worlds, hasn't been observed yet."

Enter 16 Psyche, a 140-mile diameter asteroid situated in the asteroid belt between Mars and Jupiter. Its surface, according to infrared and radar observations, is mainly iron and nickel. 16 Psyche is the subject of an upcoming NASA mission, and the asteroid inspired Soldati to think about what volcanic activity might look like on a metallic world.

"When we look at images of worlds unlike ours, we still use what happens on Earth -- like evidence of volcanic eruptions -- to interpret them," Soldati says. "However, we don't have widespread metallic volcanism on Earth, so we must imagine what those volcanic processes might look like on other worlds so that we can interpret images correctly."

Soldati defines two possible types of ferrovolcanism: Type 1, or pure ferrovolcanism, occurring on entirely metallic bodies; and Type 2, spurious ferrovolcanism, occurring on hybrid rocky-metallic bodies.

In a pilot study, Soldati and colleagues from the Syracuse Lava Project produced Type 2 ferrovolcanism, in which metal separates from rock as the magma forms.

"The Lava Project's furnace is configured for melting rock, so we were working with the metals (mainly iron) that naturally occur within them," Soldati says. "When you melt rock under the extreme conditions of the furnace, some of the iron will separate out and sink to the bottom since it's heavier. By completely emptying the furnace, we were able to see how that metal magma behaved compared to the rock one."

The metallic lava flows travelled 10 times faster and spread more thinly than the rock flows, breaking into a myriad of braided channels. The metal also traveled largely beneath the rock flow, emerging from the leading edge of the rocky lava.

The smooth, thin, braided, widely spread layers of metallic lava would leave a very different impression on a planet's surface than the often thick, rough, rocky flows we find on Earth, according to Soldati.

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The blast that shook the ionosphere

ExA 2020 explosion in Lebanon's port city of Beirut led to a southward-bound, high-velocity atmospheric wave that rivaled ones generated by volcanic eruptions.

Just after 6 p.m. local time (15.00 UTC) on August 4, 2020, more than 2,750 tons worth of unsafely stored ammonium nitrate exploded in Lebanon's port city of Beirut, killing around 200 people, making more than 300,000 temporarily homeless, and leaving a 140-metre-diameter crater in its wake. The blast is considered one of the most powerful non-nuclear, human-made explosions in human history.

Now, calculations by Hokkaido University scientists in Japan have found that the atmospheric wave from the blast led to electron disturbances high in Earth's upper atmosphere. They published their findings in the journal Scientific Reports.

The team of scientists, which included colleagues from the National Institute of Technology Rourkela in India, calculated changes in total electron content in Earth's ionosphere: the part of the atmosphere from around 50 to 965 kilometres in altitude. Natural events like extreme ultraviolet radiation and geomagnetic storms, and human-made activities like nuclear tests, can cause disturbances to the ionosphere's electron content.

"We found that the blast generated a wave that travelled in the ionosphere in a southwards direction at a velocity of around 0.8 kilometres per second," says Hokkaido University Earth and Planetary scientist Kosuke Heki. This is similar to the speed of sound waves travelling through the ionosphere.

The team calculated changes in ionospheric electron content by looking at differences in delays experienced by microwave signals transmitted by GPS satellites to their ground stations. Changes in electron content affect these signals as they pass through the ionosphere and must be regularly taken into consideration to accurately measure GPS positions.

The scientists also compared the magnitude of the ionospheric wave generated by the Beirut blast to similar waves following natural and anthropogenic events. They found that the wave generated by the Beirut blast was slightly larger than a wave generated by the 2004 eruption of Asama Volcano in central Japan, and comparable to ones that followed other recent eruptions on Japanese islands.

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Novel coronavirus circulated undetected months before first COVID-19 cases in Wuhan, China

 Using molecular dating tools and epidemiological simulations, researchers at University of California San Diego School of Medicine, with colleagues at the University of Arizona and Illumina, Inc., estimate that the SARS-CoV-2 virus was likely circulating undetected for at most two months before the first human cases of COVID-19 were described in Wuhan, China in late-December 2019.

Writing in the March 18, 2021 online issue of Science, they also note that their simulations suggest that the mutating virus dies out naturally more than three-quarters of the time without causing an epidemic.

"Our study was designed to answer the question of how long could SARS-CoV-2 have circulated in China before it was discovered," said senior author Joel O. Wertheim, PhD, associate professor in the Division of Infectious Diseases and Global Public Health at UC San Diego School of Medicine.

"To answer this question, we combined three important pieces of information: a detailed understanding of how SARS-CoV-2 spread in Wuhan before the lockdown, the genetic diversity of the virus in China and reports of the earliest cases of COVID-19 in China. By combining these disparate lines of evidence, we were able to put an upper limit of mid-October 2019 for when SARS-CoV-2 started circulating in Hubei province."

Cases of COVID-19 were first reported in late-December 2019 in Wuhan, located in the Hubei province of central China. The virus quickly spread beyond Hubei. Chinese authorities cordoned off the region and implemented mitigation measures nationwide. By April 2020, local transmission of the virus was under control but, by then, COVID-19 was pandemic with more than 100 countries reporting cases.

SARS-CoV-2 is a zoonotic coronavirus, believed to have jumped from an unknown animal host to humans. Numerous efforts have been made to identify when the virus first began spreading among humans, based on investigations of early-diagnosed cases of COVID-19. The first cluster of cases -- and the earliest sequenced SARS-CoV-2 genomes -- were associated with the Huanan Seafood Wholesale Market, but study authors say the market cluster is unlikely to have marked the beginning of the pandemic because the earliest documented COVID-19 cases had no connection to the market.

Regional newspaper reports suggest COVID-19 diagnoses in Hubei date back to at least November 17, 2019, suggesting the virus was already actively circulating when Chinese authorities enacted public health measures.

In the new study, researchers used molecular clock evolutionary analyses to try to home in on when the first, or index, case of SARS-CoV-2 occurred. "Molecular clock" is a term for a technique that uses the mutation rate of genes to deduce when two or more life forms diverged -- in this case, when the common ancestor of all variants of SARS-CoV-2 existed, estimated in this study to as early as mid-November 2019.

Molecular dating of the most recent common ancestor is often taken to be synonymous with the index case of an emerging disease. However, said co-author Michael Worobey, PhD, professor of ecology and evolutionary biology at University of Arizona: "The index case can conceivably predate the common ancestor -- the actual first case of this outbreak may have occurred days, weeks or even many months before the estimated common ancestor. Determining the length of that 'phylogenetic fuse' was at the heart of our investigation."

Based on this work, the researchers estimate that the median number of persons infected with SARS-CoV-2 in China was less than one until November 4, 2019. Thirteen days later, it was four individuals, and just nine on December 1, 2019. The first hospitalizations in Wuhan with a condition later identified as COVID-19 occurred in mid-December.

Study authors used a variety of analytical tools to model how the SARS-CoV-2 virus may have behaved during the initial outbreak and early days of the pandemic when it was largely an unknown entity and the scope of the public health threat not yet fully realized.

These tools included epidemic simulations based on the virus's known biology, such as its transmissibility and other factors. In just 29.7 percent of these simulations was the virus able to create self-sustaining epidemics. In the other 70.3 percent, the virus infected relatively few persons before dying out. The average failed epidemic ended just eight days after the index case.

"Typically, scientists use the viral genetic diversity to get the timing of when a virus started to spread," said Wertheim. "Our study added a crucial layer on top of this approach by modeling how long the virus could have circulated before giving rise to the observed genetic diversity.

"Our approach yielded some surprising results. We saw that over two-thirds of the epidemics we attempted to simulate went extinct. That means that if we could go back in time and repeat 2019 one hundred times, two out of three times, COVID-19 would have fizzled out on its own without igniting a pandemic. This finding supports the notion that humans are constantly being bombarded with zoonotic pathogens."

Wertheim noted that even as SARS-CoV-2 was circulating in China in the fall of 2019, the researchers' model suggests it was doing so at low levels until at least December of that year.

"Given that, it's hard to reconcile these low levels of virus in China with claims of infections in Europe and the U.S. at the same time," Wertheim said. "I am quite skeptical of claims of COVID-19 outside China at that time."

The original strain of SARS-CoV-2 became epidemic, the authors write, because it was widely dispersed, which favors persistence, and because it thrived in urban areas where transmission was easier. In simulated epidemics involving less dense rural communities, epidemics went extinct 94.5 to 99.6 percent of the time.

The virus has since mutated multiple times, with a number of variants becoming more transmissible.

"Pandemic surveillance wasn't prepared for a virus like SARS-CoV-2," Wertheim said. "We were looking for the next SARS or MERS, something that killed people at a high rate, but in hindsight, we see how a highly transmissible virus with a modest mortality rate can also lay the world low."

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Astronomers see a 'space jellyfish'

 A radio telescope located in outback Western Australia has observed a cosmic phenomenon with a striking resemblance to a jellyfish.

Published today in The Astrophysical Journal, an Australian-Italian team used the Murchison Widefield Array (MWA) telescope to observe a cluster of galaxies known as Abell 2877.

Lead author and PhD candidate Torrance Hodgson, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Perth, said the team observed the cluster for 12 hours at five radio frequencies between 87.5 and 215.5 megahertz.

"We looked at the data, and as we turned down the frequency, we saw a ghostly jellyfish-like structure begin to emerge," he said.

"This radio jellyfish holds a world record of sorts. Whilst it's bright at regular FM radio frequencies, at 200 MHz the emission all but disappears.

"No other extragalactic emission like this has been observed to disappear anywhere near so rapidly."

This uniquely steep spectrum has been challenging to explain. "We've had to undertake some cosmic archaeology to understand the ancient background story of the jellyfish," said Hodgson.

"Our working theory is that around 2 billion years ago, a handful of supermassive black holes from multiple galaxies spewed out powerful jets of plasma. This plasma faded, went quiet, and lay dormant.

"Then quite recently, two things happened -- the plasma started mixing at the same time as very gentle shock waves passed through the system.

"This has briefly reignited the plasma, lighting up the jellyfish and its tentacles for us to see."

The jellyfish is over a third of the Moon's diameter when observed from Earth, but can only be seen with low-frequency radio telescopes.

"Most radio telescopes can't achieve observations this low due to their design or location," said Hodgson.

The MWA -- a precursor to the Square Kilometre Array (SKA) -- is located at CSIRO's Murchison Radio-astronomy Observatory in remote Western Australia.

The site has been chosen to host the low-frequency antennas for the SKA, with construction scheduled to begin in less than a year.

Professor Johnston-Hollitt, Mr Hodgson's supervisor and co-author, said the SKA will give us an unparalleled view of the low-frequency Universe.

"The SKA will be thousands of times more sensitive and have much better resolution than the MWA, so there may be many other mysterious radio jellyfish waiting to be discovered once it's operational.

"We're about to build an instrument to make a high resolution, fast frame-rate movie of the evolving radio Universe. It will show us from the first stars and galaxies through to the present day," she said.

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Scientists uncover warehouse-full of complex molecules never before seen in space

 Scientists have discovered a vast, previously unknown reservoir of new aromatic material in a cold, dark molecular cloud by detecting individual polycyclic aromatic hydrocarbon molecules in the interstellar medium for the first time, and in doing so are beginning to answer a three-decades-old scientific mystery: how and where are these molecules formed in space?

"We had always thought polycyclic aromatic hydrocarbons were primarily formed in the atmospheres of dying stars," said Brett McGuire, Assistant Professor of Chemistry at the Massachusetts Institute of Technology, and the Project Principal Investigator for GOTHAM, or Green Bank Telescope (GBT) Observations of TMC-1: Hunting Aromatic Molecules. "In this study, we found them in cold, dark clouds where stars haven't even started forming yet."

Aromatic molecules, and PAHs -- shorthand for polycyclic aromatic hydrocarbons -- are well known to scientists. Aromatic molecules exist in the chemical makeup of human beings and other animals, and are found in food and medicines. As well, PAHs are pollutants formed from the burning of many fossil fuels and are even amongst the carcinogens formed when vegetables and meat are charred at high temperatures. "Polycyclic aromatic hydrocarbons are thought to contain as much as 25-percent of the carbon in the universe," said McGuire, who is also a research associate at the Center for Astrophysics | Harvard & Smithsonian (CfA). "Now, for the first time, we have a direct window into their chemistry that will let us study in detail how this massive reservoir of carbon reacts and evolves through the process of forming stars and planets."

Scientists have suspected the presence of PAHs in space since the 1980s but the new research, detailed in nine papers published over the past seven months, provides the first definitive proof of their existence in molecular clouds. To search out the elusive molecules, the team focused the 100m behemoth radio astronomy GBT on the Taurus Molecular Cloud, or TMC-1 -- a large, pre-stellar cloud of dust and gas located roughly 450 light-years from Earth that will someday collapse in on itself to form stars -- and what they found was astonishing: not only were the accepted scientific models incorrect, but there was a lot more going on in TMC-1 than the team could have imagined.

"From decades of previous modeling, we believed that we had a fairly good understanding of the chemistry of molecular clouds," said Michael McCarthy, an astrochemist and Acting Deputy Director of CfA, whose research group made the precise laboratory measurements that enabled many of these astronomical detections to be established with confidence. "What these new astronomical observations show is these molecules are not only present in molecular clouds, but at quantities which are orders of magnitude higher than standard models predict."

McGuire added that previous studies revealed only that there were PAH molecules out there, but not which specific ones. "For the last 30 years or so, scientists have been observing the bulk signature of these molecules in our galaxy and other galaxies in the infrared, but we couldn't see which individual molecules made up that mass. With the addition of radio astronomy, instead of seeing this large mass that we can't distinguish, we're seeing individual molecules."

Much to their surprise, the team didn't discover just one new molecule hiding out in TMC-1. Detailed in multiple papers, the team observed 1-cyanonaphthalene, 1-cyano-cyclopentadiene, HC11N, 2-cyanonaphthalene, vinylcyanoacetylene, 2-cyano-cyclopentadiene, benzonitrile, trans-(E)-cyanovinylacetylene, HC4NC, and propargylcyanide, among others. "It's like going into a boutique shop and just browsing the inventory on the front-end without ever knowing there was a back room. We've been collecting little molecules for 50 years or so and now we have discovered there's a back door. When we opened that door and looked in, we found this giant warehouse of molecules and chemistry that we did not expect," said McGuire. "There it was, all the time, lurking just beyond where we had looked before."

McGuire and other scientists at the GOTHAM project have been "hunting" for molecules in TMC-1 for more than two years, following McGuire's initial detection of benzonitrile in 2018. The results of the project's latest observations may have ramifications in astrophysics for years to come. "We've stumbled onto a whole new set of molecules unlike anything we've previously been able to detect, and that is going to completely change our understanding of how these molecules interact with each other. It has downstream ramifications," said McGuire, adding that eventually these molecules grow large enough that they begin to aggregate into the seeds of interstellar dust. "When these molecules get big enough that they're the seeds of interstellar dust, these have the possibility then to affect the composition of asteroids, comets, and planets, the surfaces on which ices form, and perhaps in turn even the locations where planets form within star systems."

The discovery of new molecules in TMC-1 also has implications for astrochemistry, and while the team doesn't yet have all of the answers, the ramifications here, too, will last for decades. "We've gone from one-dimensional carbon chemistry, which is very easy to detect, to real organic chemistry in space in the sense that the newly discovered molecules are ones that a chemist knows and recognizes, and can produce on Earth," said McCarthy. "And this is just the tip of the iceberg. Whether these organic molecules were synthesized there or transported there, they exist, and that knowledge alone is a fundamental advance in the field."

Before the launch of GOTHAM in 2018, scientists had cataloged roughly 200 individual molecules in the Milky Way's interstellar medium. These new discoveries have prompted the team to wonder, and rightly so, what's out there. "The amazing thing about these observations, about this discovery, and about these molecules, is that no one had looked, or looked hard enough," said McCarthy. "It makes you wonder what else is out there that we just haven't looked for."

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Organic crystals' ice-forming superpowers

 At the heart of clouds are ice crystals. And at the heart of ice crystals, often, are aerosol particles -- dust in the atmosphere onto which ice can form more easily than in the open air.

It's a bit mysterious how this happens, though, because ice crystals are orderly structures of molecules, while aerosols are often disorganized chunks. New research by Valeria Molinero, distinguished professor of chemistry, and Atanu K. Metya, now at the Indian Institute of Technology Patna, shows how crystals of organic molecules, a common component of aerosols, can get the job done.

The story is more than that, though -- it's a throwback to Cold War-era cloud seeding research and an investigation into a peculiar memory effect that sees ice form more readily on these crystals the second time around.

The research, funded by the Air Force Office of Scientific Research, is published in the Journal of the American Chemical Society.

Throwback to cloud seeding

Molinero's research is focused on how ice forms, particularly the process of nucleation, which is the beginning of ice crystal formation. Under the right conditions, water molecules can nucleate ice on their own. But often some other material, called a nucleant, can help the process along.

After several studies on the ways that proteins can help form ice, Molinero and Metya turned their attention to organic ice nucleants (as used here, "organic" means organic compounds containing carbon) because they are similar to the ice-producing proteins and are found in airborne aerosols.

But a review of the scientific literature found that the papers discussing ice nucleation by organic compounds came from the 1950s and 1960s, with very little follow-up work after that until very recently.

"That made me really curious," Molinero says, "because there is a lot of interest now on organic aerosols and whether and how they promote the formation of ice in clouds, but all this new literature seemed dissociated from these early fundamental studies of organic ice nucleants."

Additional research revealed that the early work on organic ice nucleants was related to the study of cloud seeding, a post-war line of research into how particles (primarily silver iodide) could be introduced into the atmosphere to encourage cloud formation and precipitation. Scientists explored the properties of organic compounds as ice nucleants to see if they might be cost-effective alternatives to silver iodide.

But cloud seeding research collapsed in the 1970s after political pressures and fears of weather modification led to a ban on the practice in warfare. Funding and interest in organic ice nucleants dried up until recently, when climate research spurred a renewed interest in the chemistry of ice formation in the atmosphere.

"There has been a growing interest in ice nucleation by organic aerosols in the last few years, but no connection to these old studies on organic crystals," Molinero says. "So, I thought it was time to "rescue" them into the modern literature."

Going all classic

Phloroglucinol is one of the organic nucleants studied in the mid-20th century. It showed promise for controlling fog, but less for cloud seeding. Molinero and Metya revisited phloroglucinol as it proved potent at ice nucleation in the lab.

One question to answer is whether phloroglucinol nucleates ice through classical or non-classical processes. When ice nucleates on its own, without any surfaces or other molecules, the only hurdle to overcome is forming a stable crystallite of ice (only about 500 molecules in size under some conditions) that other molecules can build on to grow an ice crystal. That's classical nucleation.

Non-classical nucleation, involving a nucleant surface, occurs when a layer of water molecules assembles on the surface on which other water molecules can organize into a crystal lattice. The hurdle to overcome in non-classical nucleation is the formation of the monolayer.

Which applies to phloroglucinol? In the 1960s, researcher L.F. Evans concluded that it was non-classical. "I am still amazed he was able to deduce the existence of a monolayer and infer the mechanism was non-classical from experiments of freezing as a function of temperature alone!" Molinero says. But Molinero and Metya, using molecular simulations of how ice forms, found that it's more complicated.

"We find that the step that really decides whether water transforms to ice or not is not the formation of the monolayer but the growth of an ice crystallite on top," Molinero says. "That makes ice formation by organics classical although no less fascinating."

Holding on to memories of ice

The researchers also used their simulation methods to investigate an interesting memory effect previously observed with organic and other nucleants. When ice is formed, melted and formed again using these nucleants, the second round of crystallization is more effective than the first. It's assumed that the ice melts completely between crystallizations, and researchers have posed several potential explanations.

Molinero and Metya found that the memory effect isn't due to the ice changing the nucleant surface, nor to the monolayer of water persisting on the nucleant surface after melting. Instead, their simulations supported an explanation where crevices in the nucleant can hold on to small amounts of ice that melt at higher temperatures than the rest of the ice in the experiment. If these crevices are adjacent to one of the nucleant crystal surfaces that's good at forming ice, then it's off to the races when the second round of freezing begins.

Something in the air

Other mysteries still remain -- the mid-century studies of organic crystals found that at high pressures, around 1500 times atmospheric pressure, that the crystals are as efficient at organizing water molecules into ice as an ice crystal itself. Why? That's the focus of Molinero's next experiments.

More immediately, though, phloroglucinol is a naturally-occurring compound in the atmosphere, so anything that researchers can learn about it and other organic nucleants can help explain the ability of aerosols to nucleate ice and regulate the formation of clouds and precipitation.

Read more at Science Daily

How a single cell gives rise to the 37 trillion cells in an average adult

 One of great mysteries of human biology is how a single cell can give rise to the 37 trillion cells contained in the average body, each with its own specialized role. Researchers at Yale University and the Mayo Clinic have devised a way to recreate the earliest stages of cellular development that gives rise to such an amazing diversity of cell types.

Using skin cells harvested from two living humans, researchers in the lab of Yale's Flora Vaccarino were able to track their cellular lineage by identifying tiny variations or mutations contained within the genomes of those cells.

These "somatic" or non-inherited mutations are generated at each cell division during a human's development. The percentage of cells bearing the traces of any given mutation decreases as these divisions continue, essentially leaving for scientists a trail to follow back to the earliest cells. If the fraction of cells with traces of a mutation is high, scientists know that the mutation was generated earlier in the cells' lineage, closer to its one common ancestor during early embryonic development.

"It's like Ancestry.com for our bodies,'' said Vaccarino, the Harris Professor in the Yale Child Study Center, professor of neuroscience, and co-senior author of the research published March 18 in the journal Science.

For instance, researchers knew some mutations within skin cells were generated early in embryonic development because they could also be detected in adult samples of blood, saliva, and urine. In the human body, each of those specialized tissues arise from a different germ layer, or the first differentiated cell types in an embryo that give rise to nervous system, gut, blood, and connecting tissues.

The findings show that mutations generated in the embryo are inherited and retained by each daughter cell throughout the body's development into adulthood, allowing researchers to reconstruct the early lineage trees for those individuals.

"Cellular history has consequences," Vaccarino said.

The findings also may help scientists to trace developmental disorders back to their cellular beginnings. For instance, neuropsychiatric disorders such as schizophrenia and autism can arise from early cellular malfunctions that hijack early developmental regulators. This may alter the growth and expansion of certain cell lineages or when they separate to form new cell lines during development.

Intriguingly, the researchers also found that cell lineages that diverge at the first division tend to be asymmetrical. For instance, one of the first two daughter cells created in an embryo ends up accounting for as much as 90 percent of cell types in the adult body. The other daughter cell could be dedicated primarily to creating the placenta, which will nurture the growing embryo, the researchers say.

Vaccarino stressed that the technology to track individual differences in cellular ancestry during each step of cellular development is still limited.

But it is promising. "We have figured out a minimally invasive way to peer into a window of a person's personal cellular history," she said.

Read more at Science Daily

How life on land recovered after 'The Great Dying'

 Over the course of Earth's history, several mass extinction events have destroyed ecosystems, including one that famously wiped out the dinosaurs. But none were as devastating as "The Great Dying," which took place 252 million years ago during the end of the Permian period. A new study, published today in Proceedings of the Royal Society B, shows in detail how life recovered in comparison to two smaller extinction events. The international study team -- composed of researchers from the China University of Geosciences, the California Academy of Sciences, the University of Bristol, Missouri University of Science and Technology, and the Chinese Academy of Sciences -- showed for the first time that the end-Permian mass extinction was harsher than other events due to a major collapse in diversity.

To better characterize "The Great Dying," the team sought to understand why communities didn't recover as quickly as other mass extinctions. The main reason was that the end-Permian crisis was much more severe than any other mass extinction, wiping out 19 out of every 20 species. With survival of only 5% of species, ecosystems had been destroyed, and this meant that ecological communities had to reassemble from scratch.

To investigate, lead author and Academy researcher Yuangeng Huang, now at the China University of Geosciences, Wuhan, reconstructed food webs for a series of 14 life assemblages spanning the Permian and Triassic periods. These assemblages, sampled from north China, offered a snapshot of how a single region on Earth responded to the crises. "By studying the fossils and evidence from their teeth, stomach contents, and excrement, I was able to identify who ate whom," says Huang. "It's important to build an accurate food web if we want to understand these ancient ecosystems."

The food webs are made up of plants, molluscs, and insects living in ponds and rivers, as well as the fishes, amphibians, and reptiles that eat them. The reptiles range in size from that of modern lizards to half-ton herbivores with tiny heads, massive barrel-like bodies, and a protective covering of thick bony scales. Sabre-toothed gorgonopsians also roamed, some as large and powerful as lions and with long canine teeth for piercing thick skins. When these animals died out during the end-Permian mass extinction, nothing took their place, leaving unbalanced ecosystems for ten million years. Then, the first dinosaurs and mammals began to evolve in the Triassic. The first dinosaurs were small -- bipedal insect-eaters about one meter long -- but they soon became larger and diversified as flesh- and plant-eaters.

"Yuangeng Huang spent a year in my lab," says Peter Roopnarine, Academy Curator of Geology. "He applied ecological modelling methods that allow us to look at ancient food webs and determine how stable or unstable they are. Essentially, the model disrupts the food web, knocking out species and testing for overall stability."

"We found that the end-Permian event was exceptional in two ways," says Professor Mike Benton from the University of Bristol. "First, the collapse in diversity was much more severe, whereas in the other two mass extinctions there had been low-stability ecosystems before the final collapse. And second, it took a very long time for ecosystems to recover, maybe 10 million years or more, whereas recovery was rapid after the other two crises."

Ultimately, characterizing communities -- especially those that recovered successfully -- provides valuable insights into how modern species might fare as humans push the planet to the brink.

Read more at Science Daily

Jupiter's 'dawn storm' auroras are surprisingly Earth-like

 The storms, which consist of brightenings and broadenings of the dawn flank of an oval of auroral activity that encircles Jupiter's poles, evolve in a pattern surprisingly reminiscent of familiar surges in the aurora that undulate across Earth's polar skies, called auroral substorms, according to the authors.

The new study is the first to track the storms from their birth on the nightside of the giant planet through their full evolution. It was published today in AGU Advances, AGU's journal for high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

During a dawn storm, Jupiter's quiet and regular auroral arc transforms into a complex and intensely bright auroral feature. It emits hundreds to thousands of Gigawatts of ultraviolet light into space as it rotates from the night side to the dawn side and ultimately to the day side of the planet over the course of 5-10 hours. A Gigawatt is the power produced by a typical modern nuclear reactor. This colossal brightness implies that at least ten times more energy was transferred from the magnetosphere to the upper atmosphere of Jupiter.

Previously, dawn storms had only been observed from ground-based telescopes on Earth or the Hubble Space Telescope, which can only offer side views of the aurora and cannot see the night side of the planet. Juno revolves around Jupiter every 53 days along a highly elongated orbit that brings it right above the poles every orbit.

"This is a real game changer," said Bertrand Bonfond, a researcher from the University of Liège and lead author of the new study. "We finally got to find out what was happening on the night side, where the dawn storms are born."

Familiar auroral sequences, different engines Polar auroras on Earth and on Jupiter are images of processes occurring in the magnetic fields that surround them. Both planets generate magnetic fields that capture charged particles.

Earth's magnetosphere is shaped by charged particles flowing out of the sun called the solar wind. Bursts of solar wind stretch Earth's magnetic field into a long tail on the nightside of the planet. When that tail snaps back, it fires charged particles into the nightside ionosphere, which appear as spectacular auroral light shows.

The new study found the timing of the dawn storms on Jupiter did not correlate with solar wind fluctuations. Jupiter's magnetosphere is mostly populated by particles escaping from its volcanic moon Io, which then get ionized and trapped around the planet by its magnetic field.

The sources of mass and energy fundamentally differ between these two magnetospheres, leading to auroras that usually look quite different. However, the dawn storms, as unraveled by Juno's ultraviolet spectrograph, looked familiar to the researchers.

"When we looked at the whole dawn storm sequence, we couldn't help but notice that the dawn storm auroras at Jupiter are very similar to a type of terrestrial auroras called substorms" said Zhonghua Yao, co-author of the study and scientific collaborator at the University of Liège.

The substorms result from the explosive reconfiguration of the tail of the magnetosphere. On Earth, they are strongly related to the variations of the solar wind and of the orientation of the interplanetary magnetic field. On Jupiter, such explosive reconfigurations are rather related to an overspill of the plasma originating from Io.

These findings demonstrate that, whatever their sources, particles and energy do not always circulate smoothly in planetary magnetospheres. They often accumulate until the magnetospheres collapse and generate substorm-like responses in the planetary aurorae.

Read more at Science Daily

Brain disease research reveals differences between sexes

Men and women are impacted differently by brain diseases, like Alzheimer's disease and Parkinson's disease. Researchers are urging their colleagues to remember those differences when researching treatments and cures.

In APL Bioengineering, by AIP Publishing, University of Maryland scientists highlight a growing body of research suggesting sex differences play roles in how patients respond to brain diseases, as well as multiple sclerosis, motor neuron disease, and other brain ailments.

That is progress from just a few years ago, said Alisa Morss Clyne, director of the university's Vascular Kinetics Laboratory.

"I have worked with vascular cells for 20 years and, up until maybe about five years ago, if you asked if the sex of my cells mattered at all, I would have said no," Clyne said. Then, she worked on a difficult study in which data appeared "all over the place."

"We separated the cell data by sex, and it all made sense," Clyne said. "It was an awakening for me that we should be studying this."

As of 2020, an estimated 5.8 million Americans were diagnosed with Alzheimer's disease, another 1 million with Parkinson's disease, 914,000 with multiple sclerosis, and 63,000 with motor neuron disease. These diseases happen when nerve cells in the brain and nervous system quit working and, ultimately, die.

The changes are associated with the breakdown of what is called the blood-brain barrier -- a border of cells that keeps the wrong kind of molecules in the bloodstream from entering the brain and damaging it.

Published research has shown differences in the blood-brain barriers of men and women. Some of the research suggests the barrier can be stronger in women than men, and the barriers in men and women are built and behave differently.

That could factor into known differences in the sexes, such as Alzheimer's disease being more prevalent in older women than men, while Parkinson's impacts men more frequently and tends to do so more severely.

The authors said they hope their article will serve as a reminder to researchers not just in their own field, but across the sciences, that accounting for sex differences leads to better results.

Read more at Science Daily

How hummingbirds hum

 The hummingbird is named after its pleasant humming sound when it hovers in front of flowers to feed. But only now has it become clear how the wing generates the hummingbird's namesake sound when it is beating rapidly at 40 beats per second. Researchers from Eindhoven University of Technology, Sorama, a TU/e spin-off company, and Stanford University meticulously observed hummingbirds using 12 high-speed cameras, 6 pressure plates and 2176 microphones. They discovered that the soft and complex feathered wings of hummingbirds generate sound in a fashion similar to how the simpler wings of insect do. The new insights could help make devices like fans and drones quieter.

The team of engineers succeeded in measuring the precise origin of the sound generated by the flapping wings of a flying animal for the first time. The hummingbird's hum originates from the pressure difference between the topside and underside of the wings, which changes both in magnitude and orientation as the wings flap back and forth. These pressure differences over the wing are essential, because they furnish the net aerodynamic force that enables the hummingbird bird to liftoff and hover.

Unlike other species of birds, a hummingbird wing generates a strong upward aerodynamic force during both the downward and upward wing stroke, so twice per wingbeat. Whereas both pressure differences due to the lift and drag force acting on the wing contribute, it turns out that the upward lifting pressure difference is the primary source of the hum.

The difference between whining, humming, buzzing and wooshing

Professor David Lentink of Stanford University: "This is the reason why birds and insects make different sounds. Mosquitoes whine, bees buzz, hummingbirds hum, and larger birds 'woosh'. Most birds are relatively quiet because they generate most of the lift only once during the wingbeat at the downstroke. Hummingbirds and insects are noisier because they do so twice per wingbeat."

The researchers combined all measurements in a 3D acoustic model of bird and insect wings. The model not only provides biological insight into how animals generate sound with their flapping wings, it also predicts how the aerodynamic performance of a flapping wing gives the wing sound its volume and timbre. "The distinctive sound of the hummingbird is perceived as pleasant because of the many 'overtones' created by the varying aerodynamic forces on the wing. A hummingbird wing is similar to a beautifully tuned instrument," Lentink explains with a smile.

High-tech sound camera

To arrive at their model, the scientists examined six Anna's hummingbirds, the most common species around Stanford. One by one, they had the birds drink sugar water from a fake flower in a special flight chamber. Around the chamber, not visible to the bird, cameras, microphones and pressure sensors were set up to precisely record each wingbeat while hovering in front of the flower.

You can't just go out and buy the equipment needed for this from an electronics store. CEO and researcher Rick Scholte of Sorama, a spin-off of TU Eindhoven: "To make the sound visible and be able to examine it in detail, we used sophisticated sound cameras developed by my company. The optical cameras are connected to a network of 2176 microphones for this purpose. Together they work a bit like a thermal camera that allows you to show a thermal image. We make the sound visible in a 'heat map', which enables us to see the 3D sound field in detail."

New aerodynamic force sensors

To interpret the 3D sound images, it is essential to know what motion the bird's wing is making at each sound measurement point. For that, Stanford's twelve high-speed cameras came into play, capturing the exact wing movement frame-by-frame.

Lentink: "But that's not end of story. We also needed to measure the aerodynamic forces the hummingbird's wings generates in flight. We had to develop a new instrument for that." During a follow-up experiment six highly sensitive pressure plates finally managed to record the lift and drag forces generated by the wings as they moved up and down, a first.

The terabytes of data then had to be synchronized. The researchers wanted to know exactly which wing position produced which sound and how this related to the pressure differences. Scholte: "Because light travels so much faster than sound, we had to calibrate each frame separately for both the cameras and the microphones, so that the sound recordings and the images would always correspond exactly." Because the cameras, microphones and sensors were all in different locations in the room, the researchers also had to correct for that.

Algorithm as a composite artist

Once the wing location, the corresponding sound and the pressure differences are precisely aligned for each video frame, the researchers were confronted with the complexity of interpretating high volume data. The researchers tackled this challenge harnessing artificial intelligence, the research of TU/e PhD student, and co-first author, Patrick Wijnings.

Wijnings: "We developed an algorithm for this that can interpret a 3D acoustic field from the measurements, and this enabled us to determine the most probable sound field of the hummingbird. The solution to this so-called inverse problem resembles what a police facial composite artist does: using a few clues to make the most reliable drawing of the suspect. In this way, you avoid the possibility that a small distortion in the measurements changes the outcome."

The researchers finally managed to condense all these results in a simple 3D acoustic model, borrowed from the world of airplanes and mathematically adapted to flapping wings. It predicts the sound that flapping wings radiate, not only the hum of the hummingbird, but also the woosh of other birds and bats, the buzzing and whining of insects and even the noise that robots with flapping wings generate.

Making drones quieter

Although it was not the focus of this study, the knowledge gained may also help improve aircraft and drone rotors as well as laptop and vacuum cleaner fans. The new insights and tools can help make engineered devices that generate complex forces like animals do quieter.

This is exactly what Sorama aims to do: "We make sound visible in order to make appliances quieter. Noise pollution is becoming an ever-greater problem. And a decibel meter alone is not going to solve that. You need to know where the sound comes from and how it is produced, in order to be able to eliminate it. That's what our sound cameras are for. This hummingbird wing research gives us a completely new and very accurate model as a starting point, so we can do our work even better," concludes Scholte.

Read more at Science Daily

Scientists stunned to discover plants beneath mile-deep Greenland ice

 In 1966, US Army scientists drilled down through nearly a mile of ice in northwestern Greenland -- and pulled up a fifteen-foot-long tube of dirt from the bottom. Then this frozen sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017.

In 2019, University of Vermont scientist Andrew Christ looked at it through his microscope -- and couldn't believe what he was seeing: twigs and leaves instead of just sand and rock. That suggested that the ice was gone in the recent geologic past -- and that a vegetated landscape, perhaps a boreal forest, stood where a mile-deep ice sheet as big as Alaska stands today.

Over the last year, Christ and an international team of scientists -- led by Paul Bierman at UVM, Joerg Schaefer at Columbia University and Dorthe Dahl-Jensen at the University of Copenhagen -- have studied these one-of-a-kind fossil plants and sediment from the bottom of Greenland. Their results show that most, or all, of Greenland must have been ice-free within the last million years, perhaps even the last few hundred-thousand years.

"Ice sheets typically pulverize and destroy everything in their path," says Christ, "but what we discovered was delicate plant structures -- perfectly preserved. They're fossils, but they look like they died yesterday. It's a time capsule of what used to live on Greenland that we wouldn't be able to find anywhere else."

The discovery helps confirm a new and troubling understanding that the Greenland ice has melted off entirely during recent warm periods in Earth's history -- periods like the one we are now creating with human-caused climate change.

Understanding the Greenland Ice Sheet in the past is critical for predicting how it will respond to climate warming in the future and how quickly it will melt. Since some twenty feet of sea-level rise is tied up in Greenland's ice, every coastal city in the world is at risk. The new study provides the strongest evidence yet that Greenland is more fragile and sensitive to climate change than previously understood -- and at grave risk of irreversibly melting off.

"This is not a twenty-generation problem," says Paul Bierman, a geoscientist at UVM in the College of Arts & Sciences, Rubenstein School of Environment & Natural Resources, and fellow in the Gund Institute for Environment. "This is an urgent problem for the next 50 years."

The new research was published March 15 in the Proceedings of the National Academy of Sciences.

BENEATH THE ICE

The material for the new PNAS study came from Camp Century, a Cold War military base dug inside the ice sheet far above the Arctic Circle in the 1960s. The real purpose of the camp was a super-secret effort, called Project Iceworm, to hide 600 nuclear missiles under the ice close to the Soviet Union. As cover, the Army presented the camp as a polar science station.

The military mission failed, but the science team did complete important research, including drilling a 4560-foot-deep ice core. The Camp Century scientists were focused on the ice itself -- part of the burgeoning effort at the time to understand the deep history of Earth's ice ages. They, apparently, took less interest in a bit of dirt gathered from beneath the ice core. Then, in a truly cinematic set of strange plot twists, the ice core was moved from an Army freezer to the University of Buffalo in the 1970s, to another freezer in Copenhagen, Denmark, in the 1990s, where it languished for decades -- until it surfaced when the cores were being moved to a new freezer.

For much of the Pleistocene -- the icy period covering the last 2.6 million years -- portions of the ice on Greenland persisted even during warmer spells called "interglacials." But most of this general story has been pieced together from indirect evidence in mud and rock that washed off the island and was gathered by offshore ocean drilling. The extent of Greenland's ice sheet and what kinds of ecosystems existed there before the last interglacial warm period -- that ended about 120,000 years ago -- have been hotly debated and poorly understood.

The new study makes clear that the deep ice at Camp Century -- some 75 miles inland from the coast and only 800 miles from the North Pole -- entirely melted at least once within the last million years and was covered with vegetation, including moss and perhaps trees. The new research, supported by the National Science Foundation, lines up with data from two other ice cores from the center of Greenland, collected in 1990s. Sediment from the bottom of these cores also indicate that the ice sheet was gone for some time in the recent geologic past. The combination of these cores from the center of Greenland with the new insight from Camp Century in the far northwest give researchers an unprecedented view of the shifting fate of the entire Greenland ice sheet.

The team of scientists used a series of advanced analytical techniques -- none of which were available to researchers fifty years ago -- to probe the sediment, fossils, and the waxy coating of leaves found at the bottom of the Camp Century ice core. For example, they measured ratios of rare forms -- isotopes -- of both aluminum and the element beryllium that form in quartz only when the ground is exposed to the sky and can be hit by cosmic rays. These ratios gave the scientists a window onto how long rocks at the surface were exposed vs. buried under layers of ice. This analysis gives the scientists a kind of clock for measuring what was happening on Greenland in the past. Another test used rare forms of oxygen, found in the ice within the sediment, to reveal that precipitation must have fallen at much lower elevations than the height of the current ice sheet, "demonstrating ice sheet absence," the team writes. Combining these techniques with studies of luminescence that estimate the amount of time since sediment was exposed to light, radiocarbon-dating of bits of wood in the ice, and analysis of how layers of ice and debris were arranged -- allowed the team to be clear that most, if not all, of Greenland melted at least once during the past million years -- making Greenland green with moss and lichen, and perhaps with spruce and fir trees.

And the new study shows that ecosystems of the past were not scoured into oblivion by ages of glaciers and ice sheets bulldozing overtop. Instead, the story of these living landscapes remains captured under the relatively young ice that formed on top of the ground, frozen in place, and holds them still.

In a 1960's movie about Camp Century created by the Army, the narrator notes that "more than ninety percent of Greenland is permanently frozen under a polar ice cap." This new study makes clear that it's not as permanent as we once thought. "Our study shows that Greenland is much more sensitive to natural climate warming than we used to think -- and we already know that humanity's out-of-control warming of the planet hugely exceeds the natural rate," says Christ.

Read more at Science Daily

Worlds with underground oceans may be more conducive to life than worlds with surface oceans like Earth

 One of the most profound discoveries in planetary science over the past 25 years is that worlds with oceans beneath layers of rock and ice are common in our solar system. Such worlds include the icy satellites of the giant planets, like Europa, Titan and Enceladus, and distant planets like Pluto.

In a report presented at the 52nd annual Lunar and Planetary Science Conference (LPSC 52) this week, Southwest Research Institute planetary scientist S. Alan Stern writes that the prevalence of interior water ocean worlds (IWOWs) in our solar system suggests they may be prevalent in other star systems as well, vastly expanding the conditions for planetary habitability and biological survival over time.

It has been known for many years that worlds like Earth, with oceans that lie on their surface, must reside within a narrow range of distances from their stars to maintain the temperatures that preserve those oceans. However, IWOWs are found over a much wider range of distances from their stars. This greatly expands the number of habitable worlds likely to exist across the galaxy.

Worlds like Earth, with oceans on their exterior, are also subject to many kinds of threats to life, ranging from asteroid and comet impacts, to stellar flares with dangerous radiation, to nearby supernova explosions and more. Stern's paper points out that IWOWs are impervious to such threats because their oceans are protected by a roof of ice and rock, typically several to many tens of kilometers thick, that overlie their oceans.

"Interior water ocean worlds are better suited to provide many kinds of environmental stability, and are less likely to suffer threats to life from their own atmosphere, their star, their solar system, and the galaxy, than are worlds like Earth, which have their oceans on the outside," said Stern.

He also points out that the same layer of rock and ice that protects the oceans on IWOWs also conceals life from being detected by virtually all astronomical techniques. If such worlds are the predominant abodes of life in the galaxy and if intelligent life arises in them -- both big "ifs," Stern emphasizes -- then IWOWs may also help crack the so-called Fermi Paradox. Posed by Nobel Laureate Enrico Fermi in the early 1960s, the Fermi Paradox questions why we don't see obvious evidence of life if it's prevalent across the universe.

"The same protective layer of ice and rock that creates stable environments for life also sequesters that life from easy detection," said Stern.

From Science Daily

What happened to Mars's water? It is still trapped there

 Billions of years ago, the Red Planet was far more blue; according to evidence still found on the surface, abundant water flowed across Mars and forming pools, lakes, and deep oceans. The question, then, is where did all that water go?

The answer: nowhere. According to new research from Caltech and JPL, a significant portion of Mars's water -- between 30 and 99 percent -- is trapped within minerals in the planet's crust. The research challenges the current theory that the Red Planet's water escaped into space.

The Caltech/JPL team found that around four billion years ago, Mars was home to enough water to have covered the whole planet in an ocean about 100 to 1,500 meters deep; a volume roughly equivalent to half of Earth's Atlantic Ocean. But, by a billion years later, the planet was as dry as it is today. Previously, scientists seeking to explain what happened to the flowing water on Mars had suggested that it escaped into space, victim of Mars's low gravity. Though some water did indeed leave Mars this way, it now appears that such an escape cannot account for most of the water loss.

"Atmospheric escape doesn't fully explain the data that we have for how much water actually once existed on Mars," says Caltech PhD candidate Eva Scheller (MS '20), lead author of a paper on the research that was published by the journal Science on March 16 and presented the same day at the Lunar and Planetary Science Conference (LPSC). Scheller's co-authors are Bethany Ehlmann, professor of planetary science and associate director for the Keck Institute for Space Studies; Yuk Yung, professor of planetary science and JPL senior research scientist; Caltech graduate student Danica Adams; and Renyu Hu, JPL research scientist. Caltech manages JPL for NASA.

The team studied the quantity of water on Mars over time in all its forms (vapor, liquid, and ice) and the chemical composition of the planet's current atmosphere and crust through the analysis of meteorites as well as using data provided by Mars rovers and orbiters, looking in particular at the ratio of deuterium to hydrogen (D/H).

Water is made up of hydrogen and oxygen: H2O. Not all hydrogen atoms are created equal, however. There are two stable isotopes of hydrogen. The vast majority of hydrogen atoms have just one proton within the atomic nucleus, while a tiny fraction (about 0.02 percent) exist as deuterium, or so-called "heavy" hydrogen, which has a proton and a neutron in the nucleus.

The lighter-weight hydrogen (also known as protium) has an easier time escaping the planet's gravity into space than its heavier counterpart. Because of this, the escape of a planet's water via the upper atmosphere would leave a telltale signature on the ratio of deuterium to hydrogen in the planet's atmosphere: there would be an outsized portion of deuterium left behind.

However, the loss of water solely through the atmosphere cannot explain both the observed deuterium to hydrogen signal in the Martian atmosphere and large amounts of water in the past. Instead, the study proposes that a combination of two mechanisms -- the trapping of water in minerals in the planet's crust and the loss of water to the atmosphere -- can explain the observed deuterium-to-hydrogen signal within the Martian atmosphere.

When water interacts with rock, chemical weathering forms clays and other hydrous minerals that contain water as part of their mineral structure. This process occurs on Earth as well as on Mars. Because Earth is tectonically active, old crust continually melts into the mantle and forms new crust at plate boundaries, recycling water and other molecules back into the atmosphere through volcanism. Mars, however, is mostly tectonically inactive, and so the "drying" of the surface, once it occurs, is permanent.

"Atmospheric escape clearly had a role in water loss, but findings from the last decade of Mars missions have pointed to the fact that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased water availability over time," says Ehlmann.

"All of this water was sequestered fairly early on, and then never cycled back out," Scheller says. The research, which relied on data from meteorites, telescopes, satellite observations, and samples analyzed by rovers on Mars, illustrates the importance of having multiple ways of probing the Red Planet, she says.

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Lightning strikes played a vital role in life's origins on Earth

 Lightning strikes were just as important as meteorites in creating the perfect conditions for life to emerge on Earth, geologists say.

Minerals delivered to Earth in meteorites more than 4 billion years ago have long been advocated as key ingredients for the development of life on our planet.

Scientists believed minimal amounts of these minerals were also brought to early Earth through billions of lightning strikes.

But now researchers from the University of Leeds have established that lightning strikes were just as significant as meteorites in performing this essential function and allowing life to manifest.

They say this shows that life could develop on Earth-like planets through the same mechanism at any time if atmospheric conditions are right. The research was led by Benjamin Hess during his undergraduate studies at the University of Leeds in the School of Earth and Environment.

Mr Hess and his mentors were studying an exceptionally large and pristine sample of fulgurite, -- a rock created when lightning strikes the ground. The sample was formed when lightning struck a property in Glen Ellyn, Illinois, USA, in 2016, and donated to the geology department at Wheaton College nearby.

The Leeds researchers were initially interested in how fulgurite is formed but were fascinated to discover in the Glen Ellyn sample a large amount of a highly unusual phosphorus mineral called schreibersite.

Phosphorus is essential to life and plays a key role in all life processes from movement to growth and reproduction. The phosphorus present on early Earth's surface was contained in minerals that cannot dissolve in water, but schreibersite can.

Mr Hess, now a PhD student at Yale University, Connecticut, USA, said: "Many have suggested that life on Earth originated in shallow surface waters, following Darwin's famous "warm little pond" concept.

"Most models for how life may have formed on Earth's surface invoke meteorites which carry small amounts of schreibersite. Our work finds a relatively large amount of schreibersite in the studied fulgurite.

"Lightning strikes Earth frequently, implying that the phosphorus needed for the origin of life on Earth's surface does not rely solely on meteorite hits.

"Perhaps more importantly, this also means that the formation of life on other Earth-like planets remains possible long after meteorite impacts have become rare."

The team estimate that phosphorus minerals made by lightning strikes surpassed those from meteorites when the earth was around 3.5 billion years old, which is about the age of the earliest known micro-fossils, making lightning strikes significant in the emergence of life on the planet.

Furthermore, lightning strikes are far less destructive than meteor hits, meaning they were much less likely to interfere with the delicate evolutionary pathways in which life could develop.

The research, titled Lightning strikes as a major facilitator of prebiotic phosphorus reduction on early Earth, is published today (SEE EMBARGO) in Nature Communications.

The School of Earth and Environment funded the project under a scheme which enables undergraduate led research using high-end analytical facilities.

Dr Jason Harvey, Associate Professor of Geochemistry in Leeds' School of Earth and Environment, and Sandra Piazolo, Professor of Structural Geology and Tectonics in the School of Earth and Environment, mentored Mr Hess in the research project.

Dr Harvey said: "The early bombardment is a once in a solar system event. As planets reach their mass, the delivery of more phosphorus from meteors becomes negligible.

"Lightning, on the other hand, is not such a one-off event. If atmospheric conditions are favourable for the generation of lightning, elements essential to the formation of life can be delivered to the surface of a planet.

"This could mean that life could emerge on Earth-like planets at any point in time."

Professor Piazolo said: "Our exciting research opens the door to several future avenues of investigation, including search for and in-depth analysis of fresh fulgurite in Early Earth-like environment; in-depth analysis of the effect of flash heating on other minerals to recognize such features in the rock record, and further analysis of this exceptionally well-preserved fulgurite to identify the range of physical and chemical processes within.

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94% of older adults prescribed drugs that raise risk of falling

 Nearly every older adult was prescribed a prescription drug that increased their risk of falling in 2017, according to new University at Buffalo research.

The study found that the percentage of adults 65 and older who were prescribed a fall- risk-increasing drug climbed to 94% in 2017, a significant leap from 57% in 1999. The research also revealed that the rate of death caused by falls in older adults more than doubled during the same time period.

Even minor falls may be dangerous for older adults. Falls that are not fatal can still result in injuries -- such as hip fractures and head traumas -- that may drastically lower remaining quality of life. Each year, nearly $50 billion is spent on medical costs related to fall injuries among older adults, according to the Centers for Disease Control and Prevention.

The alarming results solidify the importance of interventions to de-prescribe potentially inappropriate drugs among older, frailer patients, says Amy Shaver, PharmD, lead investigator and postdoctoral associate in the UB School of Public Health and Health Professions.

"Our study indicates two trends increasing concurrently at a population level that should be examined at the individual level. Our hope is it will start more conversations on health care teams about the pros and cons of medications prescribed for vulnerable populations," says Shaver.

Additional investigators in the UB School of Pharmacy and Pharmaceutical Sciences include Collin Clark, PharmD, clinical assistant professor; David Jacobs, PharmD, PhD, assistant professor; Robert Wahler Jr., PharmD, clinical associate professor; and Mary Hejna, PharmD, pharmacy resident at Kaleida Health.

Recently published in Pharmacoepidemiology and Drug Safety, the study examined data on deaths due to falls and prescription fills among people 65 and older from the National Vital Statistics System and the Medical Expenditure Panel Survey.

Fall-risk-increasing drugs include antidepressants, anticonvulsants, antipsychotics, antihypertensives (for high blood pressure), opioids, sedative hypnotics, and benzodiazepines (tranquilizers such as Valium and Xanax), as well as other nonprescription medications.

From 1999-2017, more than 7.8 billion fall-risk-increasing drug orders were filled by older adults in the United States. The majority of the prescriptions were for antihypertensives. However, there was also a sharp rise in the use of antidepressants, from 12 million prescriptions in 1999 to more than 52 million in 2017.

"The rise in the use of antidepressant medications seen in this study is likely related to the use of these agents as safer alternatives to older medications for conditions such as depression and anxiety," says Shaver. "However, it is important to note that these medications are still associated with increased risks of falls and fractures among older adults."

Women were also found more likely than men to be prescribed fall-risk-increasing drugs, particularly Black women, who received the medications at the highest rate compared to women of other races. White women who were 85 and older experienced the largest increase in deaths from falls, rising 160% between 1999 and 2017.

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There might be many planets with water-rich atmospheres

 An atmosphere is what makes life on Earth's surface possible, regulating our climate and sheltering us from damaging cosmic rays. But although telescopes have counted a growing number of rocky planets, scientists had thought most of their atmospheres long lost.

However, a new study by University of Chicago and Stanford University researchers suggests a mechanism whereby these planets could not only develop atmospheres full of water vapor, but keep them for long stretches. Published March 15 in the Astrophysical Journal Letters, the research expands our picture of planetary formation and could help direct the search for habitable worlds in other star systems.

"Our model is saying that these hot, rocky exoplanets should have a water-dominated atmosphere at some stage, and for some planets, it may be quite a long time," said Asst. Prof. Edwin Kite, an expert in how planetary atmospheres evolve over time.

As telescopes document more and more exoplanets, scientists are trying to figure out what they might look like. Generally, telescopes can tell you about an exoplanet's physical size, its proximity to its star and if you're lucky, how much mass it has. To go much further, scientists have to extrapolate based on what we know about Earth and the other planets in our own solar system. But the most abundant planets don't seem to be similar to the ones we see around us.

"What we already knew from the Kepler mission is that planets a little smaller than Neptune are really abundant, which was a surprise because there are none in our solar system," Kite said. "We don't know for sure what they are made of, but there's strong evidence they are magma balls cloaked in a hydrogen atmosphere."

There's also a healthy number of smaller rocky planets that are similar, but without the hydrogen cloaks. So scientists surmised that many planets probably start out like those larger planets that have atmospheres made out of hydrogen, but lose their atmospheres when the nearby star ignites and blows away the hydrogen.

But lots of details remain to be filled out in those models. Kite and co-author Laura Schaefer of Stanford University began to explore some of the potential consequences of having a planet covered in oceans of melted rock.

"Liquid magma is actually quite runny," Kite said, so it also turns over vigorously, just like oceans on Earth do. There's a good chance these magma oceans are sucking hydrogen out of the atmosphere and reacting to form water. Some of that water escapes to the atmosphere, but much more gets slurped up into the magma.

Then, after the nearby star strips away the hydrogen atmosphere, the water gets pulled out into the atmosphere instead in the form of water vapor. Eventually, the planet is left with a water-dominated atmosphere.

This stage could persist on some planets for billions of years, Kite said.

There are several ways to test this hypothesis. The James Webb Space Telescope, the powerful successor to the Hubble Telescope, is scheduled to launch later this year; it will be able to conduct measurements of the composition of an exoplanet's atmosphere. If it detects planets with water in their atmospheres, that would be one signal.

Another way to test is to look for indirect signs of atmospheres. Most of these planets are tidally locked; unlike Earth, they don't spin as they move around their sun, so one side is always hot and the other cold.

A pair of UChicago alumni have suggested a way to use this phenomenon to check for an atmosphere. Scientists Laura Kreidberg, PhD'16, and Daniel Koll, PhD'16 -- now at the Max Planck Institute for Astronomy and MIT, respectively -- pointed out that an atmosphere would moderate the temperature for the planet, so there wouldn't be a sharp difference between the day sides and night sides. If a telescope can measure how strongly the day side glows, it should be able to tell whether there's an atmosphere redistributing heat.

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Whispers from the dark side: What can gravitational waves reveal about dark matter?

 The NANOGrav Collaboration recently captured the first signs of very low-frequency gravitational waves. Prof. Pedro Schwaller and Wolfram Ratzinger analyzed the data and, in particular, considered the possibility of whether this may point towards new physics beyond the Standard Model. In an article published in the journal SciPost Physics, they report that the signal is consistent with both a phase transition in the early universe and the presence of a field of extremely light axion-like particles (ALPs). The latter are considered as promising candidates for dark matter.

Gravitational waves open a window into the early universe. While the ubiquitous cosmic microwave background yields no clues about the first 300,000 years of our universe, they provide some glimpses of what happened during Big Bang. "It's exactly this very early universe that is so exciting for particle physicists," explains Pedro Schwaller, Professor of Theoretical Physics at the PRISMA+ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU). "This is the time when the elementary particles like quarks and gluons are present, and then combine to form the building blocks of atomic nuclei."

The special thing about the gravitational waves which the NANOGrav Collaboration has detected for the first time is that they have a very low frequency of 10-8 Hertz, which equates to approximately one oscillation per year. Due to their correspondingly large wavelength, in order to detect them any detector would also have to be equally large. As such a detector is not possible here on Earth, the astronomers at NANOGrav use distant pulsars and their light signals as huge detectors.

Wolfram Ratzinger outlines the motivation behind their work: "Even though so far the data only provides us with a first hint of the existence of low-frequency gravitational waves, it is still very exciting for us to work with them. This is because such waves could be produced by various processes that occurred in the early universe. We can now use the data we already have to decide, which of these come into consideration and which do not fit the data at all."

As a result, the Mainz-based scientists decided to take a particularly close look at two scenarios that could have caused the observed gravitational waves: Phase transitions in the early universe and a dark matter field of extremely light axion-like particles (ALPs). Phase transitions such as these occur due to the falling temperature in the primordial soup after the Big Bang and result in massive turbulences -- however, like dark matter they are not covered by the Standard Model.

Based on the data available, Pedro Schwaller and Wolfram Ratzinger interpret the results of their analysis with relative caution: "Perhaps slightly more probable is the early phase transition scenario." On the other hand, the two physicists believe that the fact that they are able to work out certain possibilities based only on limited data proves the potential of their approach. "Our work is a first, but important development -- it gives us a lot of confidence that with more precise data we can draw reliable conclusions about the message gravitational waves are sending us from the early universe."

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What happens in your brain when you 'lose yourself' in fiction

 If you count yourself among those who lose themselves in the lives of fictional characters, scientists now have a better idea of how that happens.

Researchers found that the more immersed people tend to get into "becoming" a fictional character, the more they use the same part of the brain to think about the character as they do to think about themselves.

"When they think about a favorite fictional character, it appears similar in one part of the brain as when they are thinking about themselves," said Timothy Broom, lead author of the study and doctoral student in psychology at The Ohio State University.

The study was published online recently in the journal Social Cognitive and Affective Neuroscience.

The study involved scanning the brains of 19 self-described fans of the HBO series "Game of Thrones" while they thought about themselves, nine of their friends and nine characters from the series. (The characters were Bronn, Catelyn Stark, Cersei Lannister, Davos Seaworth, Jaime Lannister, Jon Snow, Petyr Baelish, Sandor Clegane and Ygritte.)

Participants reported which "Game of Thrones" character they felt closest to and liked the most.

"Game of Thrones" was a fantasy drama series lasting eight seasons and concerning political and military conflicts between ruling families on two fictional continents. It was ideal for this study, Broom said, because it attracted a devoted fan base and the large cast presented a variety of characters that people could become attached to.

One of the key findings involved participants in the study who scored highest on what is called "trait identification." In a questionnaire they completed as part of the study, these participants agreed most strongly with statements like "I really get involved in the feelings of the characters in a novel."

"People who are high in trait identification not only get absorbed into a story, they also are really absorbed into a particular character," Broom said. "They report matching the thoughts of the character, they are thinking what the character is thinking, they are feeling what the character is feeling. They are inhabiting the role of that character."

For the study, the participants' brains were scanned in an fMRI machine while they evaluated themselves, friends and "Game of Thrones" characters. An fMRI indirectly measures activity in various parts of the brain through small changes in blood flow.

The researchers were particularly interested in what was happening in a part of the brain called the ventral medial prefrontal cortex (vMPFC), which shows increased activity when people think about themselves and, to a lesser extent, when thinking about close friends.

The process was simple. While in the fMRI, participants were shown a series of names -- sometimes themselves, sometimes one of their nine friends, and other times one of the nine characters from "Game of Thrones." Each name appeared above a trait, like lonely, sad, trustworthy or smart.

Participants simply said "yes" or "no" to whether the trait described the person while the researchers simultaneously measured activity in the vMPFC portion of their brains.

As expected, the vMPFC was most active when people were evaluating themselves, less active when they evaluated friends, and least active when they evaluated "Game of Thrones" characters.

But for those who were high in trait identification, the vMPFC was more active when they thought about the fictional characters than it was for participants who identified less with the characters. That brain area was especially active when they evaluated the character they felt closest to and liked the most.

The findings help explain how fiction can have such a big impact on some people, said Dylan Wanger, co-author of the study and assistant professor of psychology at Ohio State.

"For some people, fiction is a chance to take on new identities, to see worlds though others' eyes and return from those experiences changed," Wagner said.

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