Full 3-D view of binary star-planet system

By precisely tracing a small, almost imperceptible, wobble in a nearby star's motion through space, astronomers have discovered a Jupiter-like planet orbiting that star, which is one of a binary pair. Their work, using the National Science Foundation's Very Long Baseline Array (VLBA), produced the first-ever determination of the complete, 3-dimensional structure of the orbits of a binary pair of stars and a planet orbiting one of them. This achievement, the astronomers said, can provide valuable new insights on the process of planet formation.

Though more than 5,000 extrasolar planets have been discovered so far, only three have been discovered using the technique -- called astrometry -- that produced this discovery. However, the feat of determining the 3-D architecture of a binary-star system that includes a planet "cannot be achieved with other exoplanet discovery methods," said Salvador Curiel, of the National Autonomous University of Mexico (UNAM).

"Since most stars are in binary or multiple systems, being able to understand systems such as this one will help us understand planet formation in general," Curiel said.

The two stars, which together are called GJ 896AB, are about 20 light-years from Earth -- close neighbors by astronomical standards. They are red dwarf stars, the most common type in our Milky Way galaxy. The larger one, around which the planet orbits, has about 44 percent of the mass of our Sun, while the smaller is about 17 percent as massive as the Sun. They are separated by about the distance of Neptune from the Sun, and orbit each other once every 229 years.

For their study of GJ 896AB, the astronomers combined data from optical observations of the system made between 1941 and 2017 with data from VLBA observations between 2006 and 2011. They then made new VLBA observations in 2020. The continent-wide VLBA's supersharp resolution -- ability to see fine detail -- produced extremely precise measurements of the stars' positions over time. The astronomers performed extensive analysis of the data that revealed the stars' orbital motions as well as their common motion through space.

Detailed tracing of the larger star's motion showed a slight wobble that revealed the existence of the planet. The wobble is caused by the planet's gravitational effect on the star. The star and planet orbit a location between them that represents their common center of mass. When that location, called the barycenter, is sufficiently far from the star, the star's motion around it can be detectable.

The astronomers calculated that the planet has about twice the mass of Jupiter and orbits the star every 284 days. Its distance from the star is slightly less than Venus' distance from the Sun. The planet's orbit is inclined roughly 148 degrees from the orbits of the two stars.

"This means that the planet moves around the main star in the opposite direction to that of the secondary star around the main star," said Gisela Ortiz-León, of UNAM and the Max Planck Institute for Radioastronomy. "This is the first time that such dynamical structure has been observed in a planet associated with a compact binary system that presumably was formed in the same protoplanetary disk," she added.

"Additional detailed studies of this and similar systems can help us gain important insights into how planets are formed in binary systems. There are alternate theories for the formation mechanism, and more data can possibly indicate which is most likely," said Joel Sanchez-Bermudez, of UNAM. "In particular, current models indicate that such a large planet is very unlikely as a companion to such a small star, so maybe those models need to be adjusted," he added.

The astrometric technique will be a valuable tool for characterizing more planetary systems, the astronomers said. "We can do much more work like this with the planned Next Generation VLA (ngVLA)," said Amy Mioduszewski, of the National Radio Astronomy Observatory. "With it, we may be able to find planets as small as the Earth."

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How the gut may help to drive COVID-19

New findings from Flinders University have demonstrated a molecular link between COVID-19 and serotonin cells in the gut.

The research could help provide further clues to what could be driving COVID-19 infection and disease severity and supports previous evidence that antidepressants, known as selective serotonin reuptake inhibitors (SSRIs), could reduce the severity of COVID symptoms.

COVID-19 displays an array of symptoms, which can regularly include gastrointestinal issues such as diarrhoea. Recent research has indicated that these gut symptoms in COVID-19 patients worsen with the severity of the disease, and this is linked to heightened gut-derived serotonin, released to cause gut dysfunction, increasing the body's immune response and potentially worsening patient outcomes.

Published in the world's leading gastrointestinal research journal Gut, this new collaborative study involved three Flinders research teams, including teams led by ARC DECRA Fellow Dr Alyce Martin and FAME Director of Bioinformatics and Human-Microbe Interactions, Professor Robert Edwards.

"Our study endeavoured to understand whether the gut could be a site of disease transmission and what genes might be associated with the virus entering the cells lining the gut wall," says study senior author Professor Damien Keating, Deputy Director of the Flinders Health and Medical Research Institute and Head of the Gut Sensory Systems research group.

The researchers looked at gene expression amongst the different cell types that line the gut wall, analysing whole genome sequences from thousands of individual cells from within the intestine.

They found specialised cells within the gut that synthesised and released serotonin had a highly enriched expression of a particular SARS-CoV-2 receptor and were the only type of cell that expressed all the genes associated with COVID-19.

"Many genes linked to COVID-19 were found expressed in the different cell types lining the gut wall but only serotonin cells expressed all three receptors for the virus," says Professor Keating.

"Expression of all three SARS-CoV-2 receptors triples the rate of cell infectivity, compared to expression of only two receptors."

With the exact sites of infection and the primary drivers of COVID-19 disease severity not yet fully understood, the authors say this study provides important information on the gut's role in the virus.

"Our study adds further evidence that COVID-19 is far more likely to infect cells in the gut and increase serotonin levels through direct effects on specific gut cells, potentially worsening disease outcomes," says Professor Keating.

"It also provides further support to emerging clinical evidence that antidepressant drugs, which block serotonin transport around the body, may serve as a beneficial treatment.

"As COVID-19 continues to circulate, further research will be required to advance our understanding of the gut's role in this virus and continue to find treatment options to work alongside vaccinations."

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NASA's Webb takes its first-ever direct image of distant world

For the first time, astronomers have used NASA's James Webb Space Telescope to take a direct image of a planet outside our solar system. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable.

The image, as seen through four different light filters, shows how Webb's powerful infrared gaze can easily capture worlds beyond our solar system, pointing the way to future observations that will reveal more information than ever before about exoplanets.

"This is a transformative moment, not only for Webb but also for astronomy generally," said Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter in the United Kingdom, who led these observations with a large international collaboration. Webb is an international mission led by NASA in collaboration with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

The exoplanet in Webb's image, called HIP 65426 b, is about six to 12 times the mass of Jupiter, and these observations could help narrow that down even further. It is young as planets go -- about 15 to 20 million years old, compared to our 4.5-billion-year-old Earth.

Astronomers discovered the planet in 2017 using the SPHERE instrument on the European Southern Observatory's Very Large Telescope in Chile and took images of it using short infrared wavelengths of light. Webb's view, at longer infrared wavelengths, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth's atmosphere.

Researchers have been analyzing the data from these observations and are preparing a paper they will submit to journals for peer review. But Webb's first capture of an exoplanet already hints at future possibilities for studying distant worlds.

Since HIP 65426 b is about 100 times farther from its host star than Earth is from the Sun, it is sufficiently distant from the star that Webb can easily separate the planet from the star in the image.

Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are both equipped with coronagraphs, which are sets of tiny masks that block out starlight, enabling Webb to take direct images of certain exoplanets like this one. NASA's Nancy Grace Roman Space Telescope, slated to launch later this decade, will demonstrate an even more advanced coronagraph.

"It was really impressive how well the Webb coronagraphs worked to suppress the light of the host star," Hinkley said.

Taking direct images of exoplanets is challenging because stars are so much brighter than planets. The HIP 65426 b planet is more than 10,000 times fainter than its host star in the near-infrared, and a few thousand times fainter in the mid-infrared.

In each filter image, the planet appears as a slightly differently shaped blob of light. That is because of the particulars of Webb's optical system and how it translates light through the different optics.

"Obtaining this image felt like digging for space treasure," said Aarynn Carter, a postdoctoral researcher at the University of California, Santa Cruz, who led the analysis of the images. "At first all I could see was light from the star, but with careful image processing I was able to remove that light and uncover the planet."

While this is not the first direct image of an exoplanet taken from space -- the Hubble Space Telescope has captured direct exoplanet images previously -- HIP 65426 b points the way forward for Webb's exoplanet exploration.

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SU(N) matter is about 3 billion times colder than deep space

Japanese and U.S. physicists have used atoms about 3 billion times colder than interstellar space to open a portal to an unexplored realm of quantum magnetism.

"Unless an alien civilization is doing experiments like these right now, anytime this experiment is running at Kyoto University it is making the coldest fermions in the universe," said Rice University's Kaden Hazzard, corresponding theory author of a studypublished today in Nature Physics. "Fermions are not rare particles. They include things like electrons and are one of two types of particles that all matter is made of."

A Kyoto team led by study author Yoshiro Takahashi used lasers to cool its fermions, atoms of ytterbium, within about one-billionth of a degree of absolute zero, the unattainable temperature where all motion stops. That's about 3 billion times colder than interstellar space, which is still warmed by the afterglow from the Big Bang.

"The payoff of getting this cold is that the physics really changes," Hazzard said. "The physics starts to become more quantum mechanical, and it lets you see new phenomena."

Atoms are subject to the laws of quantum dynamics just like electrons and photons, but their quantum behaviors only become evident when they are cooled within a fraction of a degree of absolute zero. Physicists have used laser cooling to study the quantum properties of ultracold atoms for more than a quarter century. Lasers are used to both cool the atoms and restrict their movements to optical lattices, 1D, 2D or 3D channels of light that can serve as quantum simulators capable of solving complex problems beyond the reach of conventional computers.

Takahashi's lab used optical lattices to simulate a Hubbard model, an oft-used quantum model created in 1963 by theoretical physicist John Hubbard. Physicists use Hubbard models to investigate the magnetic and superconducting behavior of materials, especially those where interactions between electrons produce collective behavior, somewhat like the collective interactions of cheering sports fans who perform "the wave" in crowded stadiums.

"The thermometer they use in Kyoto is one of the important things provided by our theory," said Hazzard, associate professor of physics and astronomy and a member of the Rice Quantum Initiative. "Comparing their measurements to our calculations, we can determine the temperature. The record-setting temperature is achieved thanks to fun new physics that has to do with the very high symmetry of the system."

The Hubbard model simulated in Kyoto has special symmetry known as SU(N), where SU stands for special unitary group -- a mathematical way of describing the symmetry -- and N denotes the possible spin states of particles in the model. The greater the value of N, the greater the model's symmetry and the complexity of magnetic behaviors it describes. Ytterbium atoms have six possible spin states, and the Kyoto simulator is the first to reveal magnetic correlations in an SU(6) Hubbard model, which are impossible to calculate on a computer.

"That's the real reason to do this experiment," Hazzard said. "Because we're dying to know the physics of this SU(N) Hubbard model."

Study co-author Eduardo Ibarra-García-Padilla, a graduate student in Hazzard's research group, said the Hubbard model aims to capture the minimal ingredients to understand why solid materials become metals, insulators, magnets or superconductors.

"One of the fascinating questions that experiments can explore is the role of symmetry," Ibarra-García-Padilla said. "To have the capability to engineer it in a laboratory is extraordinary. If we can understand this, it may guide us to making real materials with new, desired properties."

Takahashi's team showed it could trap up to 300,000 atoms in its 3D lattice. Hazzard said accurately calculating the behavior of even a dozen particles in an SU(6) Hubbard model is beyond the reach of the most powerful supercomputers. The Kyoto experiments offer physicists a chance to learn how these complex quantum systems operate by watching them in action.

The results are a major step in this direction, and include the first observations of particle coordination in an SU(6) Hubbard model, Hazzard said.

"Right now this coordination is short-ranged, but as the particles are cooled even further, subtler and more exotic phases of matter can appear," he said. "One of the interesting things about some of these exotic phases is that they are not ordered in an obvious pattern, and they are also not random. There are correlations, but if you look at two atoms and ask, 'Are they correlated?' you won't see them. They are much more subtle. You can't look at two or three or even 100 atoms. You kind of have to look at the whole system."

Physicists don't yet have tools capable of measuring such behavior in the Kyoto experiment. But Hazzard said work is already underway to create the tools, and the Kyoto team's success will spur those efforts.

"These systems are pretty exotic and special, but the hope is that by studying and understanding them, we can identify the key ingredients that need to be there in real materials," he said.

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Motion of DNA linked to its damage response, ability to repair itself

A multidisciplinary team of Indiana University researchers have discovered that the motion of chromatin, the material that DNA is made of, can help facilitate effective repair of DNA damage in the human nucleus -- a finding that could lead to improved cancer diagnosis and treatment. Their findings were recently published in the Proceedings of the National Academy of Sciences.

DNA damage happens naturally in human body and most of the damage can be repaired by the cell itself. However, unsuccessful repair could lead to cancer.

"DNA in the nucleus is always moving, not static. The motion of its high-order complex, chromatin, has a direct role in influencing DNA repair," said Jing Liu, an assistant professor of physics in the School of Science at IUPUI. "In yeast, past research shows that DNA damage promotes chromatin motion, and the high mobility of it also facilitates the DNA repair. However, in human cells this relationship is more complicated."

Liu and his colleagues found that chromatin on the site of DNA damage moves much faster than those away from the DNA damage. They also found that the chromatin in cell nuclei is not moving randomly. It's a coherent movement, with the DNA moving as a group over a short distance.

The researchers also found evidence that DNA damage may affect the DNA's group movement by reducing the coherence. These findings indicate that chromatin motion is under tight control when DNA is damaged. This is important to prevent the damaged DNA from harmful contact and to improve the accuracy and efficacy of DNA repair, Liu said.

"Our findings reveal a fundamental role of the chromatin motion in DNA damage response and DNA repair," Liu said. "These findings can help to understand the mechanism of DNA repair in human cells and cancer initiation in humans. Practically, we can use these findings as the metrics for the drug response of many different drugs used to treat cancer. We can test different drugs to see if the chromatin motion can be modified to enhance DNA repair."

In order to conduct this research, Liu and his colleagues had to develop the computational tools necessary for analyzing massive amounts of data. With data sizes as large as a terabyte in some cases, Liu and his colleagues worked with IU's University Information Technology Services to establish the Scalable Data Archive of highly dynamic cell images, which centralizes data storage, data transfer, and data processing.

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People generate their own oxidation field and change the indoor air chemistry around them

People typically spend 90 percent of their lives inside, at home, at work, or in transport. Within these enclosed spaces, occupants are exposed to a multitude of chemicals from various sources, including outdoor pollutants penetrating indoors, gaseous emissions from building materials and furnishings, and products of our own activities such as cooking and cleaning. In addition, we are ourselves potent mobile emission sources of chemicals that enter the indoor air from our breath and skin.

But how do the chemicals disappear again? In the atmosphere outdoors, this happens to a certain extent naturally by itself, when it rains and through chemical oxidation. Hydroxyl (OH) radicals are largely responsible for this chemical cleaning. These very reactive molecules are also called the detergents of the atmosphere and they are primarily formed when UV light from the sun interacts with ozone and water vapor.

Indoors, on the other hand, the air is of course far less affected by direct sunlight and rain. Since UV rays are largely filtered out by glass windows it has been generally assumed that the concentration of OH radicals is substantially lower indoors than outdoors and that ozone, leaking in from outdoors, is the major oxidant of indoor airborne chemical pollutants.

OH radicals are formed from ozone and skin oils

However, now it has been discovered that high levels of OH radicals can be generated indoors, simply due to the presence of people and ozone. This has been shown by a team led by the Max Planck Institute for Chemistry in cooperation with researchers from the USA and Denmark.

"The discovery that we humans are not only a source of reactive chemicals, but we are also able to transform these chemicals ourselves was very surprising to us," says Nora Zannoni, first author of the study published in the research magazine Science, and now at the Institute of Atmospheric Sciences and Climate in Bologna, Italy. "The strength and shape of the oxidation field are determined by how much ozone is present, where it infiltrates, and how the ventilation of the indoor space is configured," adds the scientist from Jonathan Williams' team. The levels the scientists found were even comparable to outside daytime OH concentrations levels.

The oxidation field is generated by the reaction of ozone with oils and fats on our skin, especially the unsaturated triterpene squalene, which constitutes about 10 percent of the skin lipids that protect our skin and keep it supple. The reaction releases a host of gas phase chemicals containing double bonds that react further in the air with ozone to generate substantial levels of OH radicals. These squalene degradation products were characterized and quantified individually using Proton Transfer reaction Mass Spectrometry and fast gas chromatograph-mass spectrometry systems. In addition, the total OH reactivity was determined in parallel enabling the OH levels to be quantified empirically.

The experiments were conducted at the Technical University of Denmark (DTU) in Copenhagen. Four test subjects stayed in a special climate-controlled chamber under standardized conditions. Ozone was added to the chamber air inflow in a quantity that was not harmful to humans but representative of higher indoor levels. The team determined the OH values before and during the volunteers' stay both with and without ozone present.

In order to understand how the human-generated OH field looked like in space and time during the experiments, results from a detailed multiphase chemical kinetic model from the University of California, Irvine were combined with a computational fluid dynamics model from Pennsylvania State University, both based in the USA. After validating the models against the experimental results, the modeling team examined how the human-generated OH field varied under different conditions of ventilation and ozone, beyond those tested in the laboratory. From the results, it was clear that the OH radicals were present, abundant, and forming strong spatial gradients.

"Our modeling team is the first and currently the only group that can integrate chemical processes between the skin and indoor air, from molecular scales to room scales," said Manabu Shiraiwa, a professor at UC Irvine who led the modeling part of the new work. "The model makes sense of the measurements -- why OH is generated from the reaction with the skin."

Shiraiwa added that there remain unanswered questions, like the way humidity levels impact the reactions the team traced. "I think this study opens up a new avenue for indoor air research," he said.

Adapt test methods for furniture and building materials

"We need to rethink indoor chemistry in occupied spaces because the oxidation field we create will transform many of the chemicals in our immediate vicinity. OH can oxidize many more species than ozone, creating a multitude of products directly in our breathing zone with as yet unknown health impacts." This oxidation field will also impact the chemical signals we emit and receive," says project leader Jonathan Williams, "and possibly help explain the recent finding that our sense of smell is generally more sensitive to molecules that react faster with OH."

The new finding also has implications for our health: Currently, chemical emissions of many materials and furnishings are being tested in isolation before they are approved for sale. However, it would be advisable to also conduct tests in the presence of people and ozone, says atmospheric chemist Williams. This is because oxidation processes can lead to the generation of respiratory irritants such as 4-oxopentanal (4-OPA) and other OH radical-generated oxygenated species, and small particles in the immediate vicinity of the respiratory tract. These can have adverse effects, especially in children and the infirm.

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MOXIE experiment reliably produces oxygen on Mars

On the red and dusty surface of Mars, nearly 100 million miles from Earth, an instrument the size of a lunchbox is proving it can reliably do the work of a small tree.

The MIT-led Mars Oxygen In-Situ Resource Utilization Experiment, or MOXIE, has been successfully making oxygen from the Red Planet's carbon-dioxide-rich atmosphere since February 2021, when it touched down on the Martian surface as part of NASA's Perseverance rover mission.

In a study published in the journal Science Advances, researchers report that, by the end of 2021, MOXIE was able to produce oxygen on seven experimental runs, in a variety of atmospheric conditions, including during the day and night, and through different Martian seasons. In each run, the instrument reached its target of producing six grams of oxygen per hour -- about the rate of a modest tree on Earth.

Researchers envision that a scaled-up version of MOXIE could be sent to Mars ahead of a human mission, to continuously produce oxygen at the rate of several hundred trees. At that capacity, the system should generate enough oxygen to both sustain humans once they arrive, and fuel a rocket for returning astronauts back to Earth.

So far, MOXIE's steady output is a promising first step toward that goal.

"We have learned a tremendous amount that will inform future systems at a larger scale," says Michael Hecht, principal investigator of the MOXIE mission at MIT's Haystack Observatory.

MOXIE's oxygen production on Mars also represents the first demonstration of "in-situ resource utilization," which is the idea of harvesting and using a planet's materials (in this case, carbon dioxide on Mars) to make resources (such as oxygen) that would otherwise have to be transported from Earth.

"This is the first demonstration of actually using resources on the surface of another planetary body, and transforming them chemically into something that would be useful for a human mission," says MOXIE deputy principal investigator Jeffrey Hoffman, a professor of the practice in MIT's Department of Aeronautics and Astronautics. "It's historic in that sense."

Hoffman and Hecht's MIT co-authors include MOXIE team members Jason SooHoo, Andrew Liu, Eric Hinterman, Maya Nasr, Shravan Hariharan, and Kyle Horn, along with collaborators from multiple institutions including NASA's Jet Propulsion Laboratory, which managed MOXIE's development, flight software, packaging, and testing prior to launch.

Seasonal air

The current version of MOXIE is small by design, in order to fit aboard the Perseverance rover, and is built to run for short periods, starting up and shutting down with each run, depending on the rover's exploration schedule and mission responsibilities. In contrast, a full-scale oxygen factory would include larger units that would ideally run continuously.

Despite the necessary compromises in MOXIE's current design, the instrument has shown it can reliably and efficiently convert Mars' atmosphere into pure oxygen. It does so by first drawing the Martian air in through a filter that cleans it of contaminants. The air is then pressurized, and sent through the Solid OXide Electrolyzer (SOXE), an instrument developed and built by OxEon Energy, that electrochemically splits the carbon dioxide-rich air into oxygen ions and carbon monoxide.

The oxygen ions are then isolated and recombined to form breathable, molecular oxygen, or O2, which MOXIE then measures for quantity and purity before releasing it harmlessly back into the air, along with carbon monoxide and other atmospheric gases.

Since the rover's landing in February 2021, MOXIE engineers have started up the instrument seven times throughout the Martian year, each time taking a few hours to warm up, then another hour to make oxygen before powering back down. Each run was scheduled for a different time of day or night, and in different seasons, to see whether MOXIE could accommodate shifts in the planet's atmospheric conditions.

"The atmosphere of Mars is far more variable than Earth," Hoffman notes. "The density of the air can vary by a factor of two through the year, and the temperature can vary by 100 degrees. One objective is to show we can run in all seasons."

So far, MOXIE has shown that it can make oxygen at almost any time of the Martian day and year.

"The only thing we have not demonstrated is running at dawn or dusk, when the temperature is changing substantially," Hecht says. "We do have an ace up our sleeve that will let us do that, and once we test that in the lab, we can reach that last milestone to show we can really run any time."

Ahead of the game

As MOXIE continues to churn out oxygen on Mars, engineers plan to push its capacity, and increase its production, particularly in the Martian spring, when atmospheric density and carbon dioxide levels are high.

"The next run coming up will be during the highest density of the year, and we just want to make as much oxygen as we can," Hecht says. "So we'll set everything as high as we dare, and let it run as long as we can."

They will also monitor the system for signs of wear and tear. As MOXIE is just one experiment among several aboard the Perseverance rover, it cannot run continuously as a full-scale system would. Instead, the instrument must start up and shut down with each run -- a thermal stress that can degrade the system over time.

If MOXIE can operate successfully despite repeatedly turning on and off, this would suggest that a full-scale system, designed to run continuously, could do so for thousands of hours.

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Signs of saturation emerge from particle collisions at RHIC

Nuclear physicists studying particle collisions at the Relativistic Heavy Ion Collider (RHIC) -- a U.S. Department of Energy Office of Science user facility at DOE's Brookhaven National Laboratory -- have new evidence that particles called gluons reach a steady "saturated" state inside the speeding ions. The evidence is suppression of back-to-back pairs of particles emerging from collisions between protons and heavier ions (the nuclei of atoms), as tracked by RHIC's STAR detector. In a paper just published in Physical Review Letters, the STAR collaboration shows that the bigger the nucleus the proton collides with, the larger the suppression in this key signature, as predicted by theoretical models of gluon saturation.

"We varied the species of the colliding ion beam because theorists predicted that this sign of saturation would be easier to observe in heavier nuclei," explained Brookhaven Lab physicist Xiaoxuan Chu, a member of the STAR collaboration who led the analysis. "The good thing is RHIC, the world's most flexible collider, can accelerate different species of ion beams. In our analysis, we used collisions of protons with other protons, aluminum, and gold."

Saturation should be easier to see in aluminum, and even easier in gold, when compared to simpler protons, Chu explained, because these bigger nuclei have more protons and neutrons, each made up of quarks and gluons.

Previous experiments have shown that when ions are accelerated to high energies, gluons split, one into two, to multiply to very high numbers. But scientists suspect that gluon multiplication can't go on forever. Instead, in nuclei moving close to the speed of light, where relativistic motion flattens the nuclei into speeding gluon "pancakes," overlapping gluons should start to recombine.

"If the rate of two gluons recombining into one balances out the rate of single gluons splitting, gluon density reaches a steady state, or plateau, where it is not going up or going down. That is saturation," Chu said. "Because there are more gluons and more overlapping gluons in larger nuclei, these bigger ions should show signs of recombination and saturation more readily than smaller ones," she added.

Scanning for back-to-back pairs

To search for those signs, the STAR scientists scanned data collected in 2015 for collisions where a pair of "pi zero" particles hit STAR's forward meson spectrometer in a back-to-back configuration. In this case, back-to-back means 180 degrees from one another around a circular target at the end of the detector in the forward-going direction of the probing proton beam. These collisions select for interactions between a single high-energy quark from the probing proton with a single low-momentum gluon in the target ion (proton, aluminum, or gold).

"We use the quark from the proton like a tool, or probe, to study the gluon inside the other ion," Chu said.

The team was particularly interested in the "low momentum fraction" gluons -- the multitude of gluons that each carry a tiny fraction of the overall momentum of the nucleus. Experiments at the HERA accelerator in Germany (1992-2007) have shown that, at high energy, protons and all nuclei are dominated by these low-momentum-fraction gluons.

In the proton-proton collisions, the quark-gluon interactions are very straightforward, Chu explained. "The two particles -- quark and gluon -- hit each other and generate two pi zero particles back-to-back," she said.

But when a quark from the proton strikes a gluon in a larger flattened-out nucleus, where many gluons overlap, the interactions can be more complex. The quark -- or the struck gluon -- might strike multiple additional gluons. Or the gluon might recombine with another gluon, losing all "memory" of its original tendency to emit a pi zero.

Both processes -- multiple scatterings and gluon recombination -- should "smear" the back-to-back pi zero signal, explained Elke Aschenauer, the leader of Brookhaven Lab's "Cold QCD" experimental group, which explores details of quantum chromodynamics (QCD), the theory governing the interactions of quarks and gluons in protons and nuclei.

"So, the proton-proton collisions give us a baseline," said Chu. "In these collisions we don't have saturation because there aren't enough gluons and not enough overlap. To look for saturation, we compare the observable of the two-particle correlation across the three collision systems."

Results match theory prediction

The results came out just as the theories predicted, with the physicists observing the fewest back-to-back correlated particles striking the detector in the proton-gold collisions, an intermediate level in proton-aluminum collisions, and the highest correlation in the baseline proton-proton collisions.

The suppression of the pi zero correlation in the larger nuclei, and the fact that the suppression gets stronger the larger the nucleus gets, are clear evidence, the scientists say, of gluon recombination needed to reach gluon saturation.

"STAR will follow up these measurements by collecting additional data in 2024 using recently upgraded forward detector components, tracking other observables that should also be sensitive to saturation," explained Brookhaven Lab physicist Akio Ogawa, a member of the STAR collaboration and a key player in building the new forward STAR detector systems.

Together, the RHIC results will also be an important basis for very similar measurements at the future Electron-Ion Collider (EIC), being built at Brookhaven to collide electrons with ions.

According to Aschenauer, one of the physicists laying out the plans for research at that facility, "If we measure this now at RHIC, at a collision energy of 200 billion electron volts (GeV), that is very similar to the collision energy we will get at the EIC. That means we can use the same observable at the EIC to test whether recombination and saturation are universal properties of the nuclei, as predicted by the saturation models."

Seeing the same result at both facilities, "would prove that these properties don't depend on structure and type of the probe we use to study them," she said.

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What you know changes how you see things

Researchers at the George Washington University have gained important insight into how the human brain processes an object in the visual system and where in the brain this processing takes place. Their study, "Mugs and Plants: Object Semantic Knowledge Alters Perceptual Processing with Behavioral Ramifications," shows people perceive objects differently depending on their prior knowledge and experience with that object.

The findings could have important implications in applied settings such as medical displays, cognitive assistants, and product and environmental design, according to the researchers.

"Since the way we perceive objects determines how we interact with them, it is important to visually process them quickly and with high detail" Sarah Shomstein, a professor of cognitive neuroscience at GW said. "However, the way our eyes perceive and process an object can be different depending on what we know about this object. Our study shows, for the first time, that if we recognize an object as a tool, we perceive it faster but with less detail. If we recognize an object as a non-tool, we perceive it slower but with higher detail."

To determine how the human brain processes an object visually, Shomstein and Dick Dubbelde, a recent PhD graduate at GW and co-author on the study, showed participants several images of objects that can be easily manipulated by hand such as a coffee mug, snow shovel or screwdriver, and several images of objects that are infrequently manipulated by hand, such as a potted plant, a picture frame or a fire hydrant. For half of the experiment, a small gap could be cut out of the bottom of each object. For the other half of the experiment, the objects could flicker on the screen. The team asked participants to report the presence or absence of a gap or the flicker, which helped the researchers figure out the speed and detail of object processing, and also which regions of the brain were being used to process the object.

Researchers found that objects usually manipulated by your hands are perceived faster than non-manipulable objects, making it easier to see the flickering. Alternatively, objects that we usually do not manipulate are perceived with greater detail than manipulable objects, making it easier to see the small gaps.

"The differences in perception between 'mugs' and 'plants' in both speed and detail of perception means that these objects are sorted by the visual system for processing in different brain regions," Dubbelde said. "In other words, your knowledge of the object's purpose actually determines where in the brain object processing will occur and how well you will perceive it."

The study also showed that if you interfere with object recognition by making it harder to recognize an object as either manipulable or not manipulable -- for example, by turning it upside down -- then the differences in the speed and detail perception of the objects disappear.

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Corals pass mutations acquired during their lifetimes to offspring

In a discovery that challenges over a century of evolutionary conventional wisdom, corals have been shown to pass somatic mutations -- changes to the DNA sequence that occur in non-reproductive cells -- to their offspring. The finding, by an international team of scientists led by Penn State biologists, demonstrates a potential new route for the generation of genetic diversity, which is the raw material for evolutionary adaptation, and could be vital for allowing endangered corals to adapt to rapidly changing environmental conditions.

"For a trait, such as growth rate, to evolve, the genetic basis of that trait must be passed from generation to generation," said Iliana Baums, professor of biology at Penn State and leader of the research team. "For most animals, a new genetic mutation can only contribute to evolutionary change if it occurs in a germline or reproductive cell, for example in an egg or sperm cell. Mutations that occur in the rest of the body, in the somatic cells, were thought to be evolutionarily irrelevant because they do not get passed on to offspring. However, corals appear to have a way around this barrier that seems to allow them to break this evolutionary rule."

Since the time of Darwin, our understanding of evolution has become ever more detailed. We now know that an organism's traits are heavily determined by the sequence of their DNA. Individuals in a population vary in their DNA sequence, and this genetic variation can lead to the variation in traits, such as body size, that could give an individual a reproductive advantage. Only rarely does a new genetic mutation occur that gives an individual such a reproductive advantage and evolution can only proceed further if -- and this is the key -- the individual can pass the change to its offspring.

"In most animals, reproductive cells are segregated from body cells early in development," said Kate Vasquez Kuntz, a graduate student at Penn State and the co-lead author of the study. "So only genetic mutations that occur in the reproductive cells have the potential to contribute to the evolution of the species. This slow process of waiting for rare mutations in a particular set of cells can be particularly problematic given the rapid nature of climate change. However, for some organisms, like corals, the segregation of reproductive cells from all other cells may occur later in development or may never occur at all, allowing a path for genetic mutations to travel from a parent's body to its offspring. This would increase genetic variation and potentially even serve as a 'pre-screening' system for advantageous mutations."

Corals can reproduce both asexually (through budding and colony fragmentation) and sexually, by producing egg and sperm cells. For the Elkhorn corals studied here, which broadcast their egg and sperm cells into the water in spawning events, eggs from one coral colony are usually fertilized by sperm from a neighboring colony. However, the research team found that some Elkhorn coral eggs developed into viable offspring without a second coral being involved, a kind of single-parent sexual reproduction.

"This single-parent reproduction allowed us to more easily search for potential somatic mutations from the parent coral and track them into the offspring by simplifying the total number of genetic possibilities that could occur in the offspring," said Sheila Kitchen, co-lead author of the study, a postdoctoral researcher at Penn State and the California Institute of Technology co-lead author of the study.

The research team genotyped samples -- using a high-resolution molecular tool called a microarray to investigate DNA differences between the samples -- from ten different locations on a large Elkhorn coral colony that had produced single-parent offspring, and samples from five neighboring colonies at nearly 20,000 genetic locations. The results showed that all six of the separate coral colonies belonged to the same original coral genotype (known as a "genet"), meaning essentially that they were clones derived from a single original colony through asexual reproduction and colony fragmentation. Thus, any genetic variation found in these corals would have been the result of somatic mutation. The team found a total of 268 somatic mutations in the samples, with each coral sample harboring between 2 and 149 somatic mutations.

The team then looked at the single-parent offspring from the parent Elkhorn coral colony and found that 50% of the somatic mutations had been inherited. The exact mechanism of how the somatic mutations make their way into germline cells in the corals is still unknown, but the researchers suspect that the segregation between body and germline cells in corals may be incomplete and some body cells may retain the capacity to form germ cells, allowing somatic mutations to make their way into offspring. They also found evidence for the inheritance of somatic mutations in some offspring from the mating of two separate coral parents but will need additional studies to confirm this.

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Land plants changed Earth's composition

Scientists at the University of Southampton have discovered that the evolution of land plants caused a sudden shift in the composition of Earth's continents.

The Southampton researchers, led by Dr Tom Gernon, working with Queen's University Canada, led by Dr Christopher Spencer, and colleagues at the University of Cambridge, the University of Aberdeen, and the China University of Geosciences, Wuhan, studied the effects of land plant evolution on Earth's chemical composition over the past 700 million years.

The researchers' findings are published in the journal Nature Geoscience.

The evolution of land plants took place about 430 million years ago during the Silurian Period, when North America and Europe were conjoined in a landmass called Pangaea.

The proliferation of plants completely transformed Earth's biosphere -- those parts of the planet's surface where life thrives -- paving the way for the advent of dinosaurs about 200 million years later.

"Plants caused fundamental changes to river systems, bringing about more meandering rivers and muddy floodplains, as well as thicker soils," says Dr Christopher Spencer, Assistant Professor at Queen's University in Kingston, Ontario, lead author of the study. "This shift was tied to the development of plant rooting systems that helped produce colossal amounts of mud (by breaking down rocks) and stabilised river channels, which locked up this mud for long periods."

The team recognised that Earth's surface and deep interior are linked by plate tectonics -- rivers flush mud into the oceans, and this mud then gets dragged into the Earth's molten interior (or mantle) at subduction zones where it gets melted to form new rocks.

"When these rocks crystallise, they trap in vestiges of their past history," says Dr Tom Gernon, Associate Professor of Earth Science at the University of Southampton and co-author of the study. "So, we hypothesised that the evolution of plants should dramatically slow down the delivery of mud to the oceans, and that this feature should be preserved in the rock record -- it's that simple."

To test this idea, the team studied a database of over five thousand zircon crystals formed in magmas at subduction zones -- essentially 'time capsules' that preserve vital information on the chemical conditions that prevailed on Earth when they crystallised.

The team uncovered compelling evidence for a dramatic shift in the composition of rocks making up Earth's continents, which coincides almost precisely with the onset of land plants.

Notably, the scientists also found that the chemical characteristics of zircon crystals generated at this time indicate a significant slowing down of sediment transfer to the oceans, just as they had hypothesised.

The researchers show that vegetation changed not only the surface of the Earth, but also the dynamics of melting in Earth's mantle.

"It is amazing to think that the greening of the continents was felt in the deep Earth," concludes Dr Spencer.

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Diamonds and rust at Earth's core-mantle boundary

Steel rusts by water and air on the Earth's surface. But what about deep inside the Earth's interior?

The Earth's core is the largest carbon storage on Earth -- roughly 90% is buried there. Scientists have shown that the oceanic crust that sits on top of tectonic plates and falls into the interior, through subduction, contains hydrous minerals and can sometimes descend all the way to the core-mantle boundary. The temperature at the core-mantle boundary is at least twice as hot as lava, and high enough that water can be released from the hydrous minerals. Therefore, a chemical reaction similar to rusting steel could occur at Earth's core-mantle boundary.

Byeongkwan Ko, a recent Arizona State University PhD graduate, and his collaborators published their findings on the core-mantle boundary in Geophysical Research Letters. They conducted experiments at the Advanced Photon Source at Argonne National Laboratory, where they compressed iron-carbon alloy and water together to the pressure and temperature expected at the Earth's core-mantle boundary, melting the iron-carbon alloy.

The researchers found that water and metal react and make iron oxides and iron hydroxides, just like what happens with rusting at Earth's surface. However, they found that for the conditions of the core-mantle boundary carbon comes out of the liquid iron-metal alloy and forms diamond.

"Temperature at the boundary between the silicate mantle and the metallic core at 3,000 km depth reaches to roughly 7,000 F, which is sufficiently high for most minerals to lose H2O captured in their atomic scale structures," said Dan Shim, professor at ASU's School of Earth and Space Exploration. "In fact, the temperature is high enough that some minerals should melt at such conditions."

Because carbon is an iron loving element, significant carbon is expected to exist in the core, while the mantle is thought to have relatively low carbon. However, scientists have found that much more carbon exists in the mantle than expected.

"At the pressures expected for the Earth's core-mantle boundary, hydrogen alloying with iron metal liquid appears to reduce solubility of other light elements in the core," said Shim. "Therefore, solubility of carbon, which likely exists in the Earth's core, decreases locally where hydrogen enters into the core from the mantle (through dehydration). The stable form of carbon at the pressure-temperature conditions of Earth's core-mantle boundary is diamond. So the carbon escaping from the liquid outer core would become diamond when it enters into the mantle."

"Carbon is an essential element for life and plays an important role in many geological processes," said Ko. "The new discovery of a carbon transfer mechanism from the core to the mantle will shed light on the understanding of the carbon cycle in the Earth's deep interior. This is even more exciting given that the diamond formation at the core-mantle boundary might have been going on for billions of years since the initiation of subduction on the planet."

Ko's new study shows that carbon leaking from the core into the mantle by this diamond formation process may supply enough carbon to explain the elevated carbon amounts in the mantle. Ko and his collaborators also predicted that diamond rich structures can exist at the core-mantle boundary and that seismic studies might detect the structures because seismic waves should travel unusually fast for the structures.

"The reason that seismic waves should propagate exceptionally fast through diamond-rich structures at the core-mantle boundary is because diamond is extremely incompressible and less dense than other materials at the core-mantle boundary," said Shim.

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How the brain generates rhythmic behavior

Many of our bodily functions, such as walking, breathing, and chewing, are controlled by brain circuits called central oscillators, which generate rhythmic firing patterns that regulate these behaviors.

MIT neuroscientists have now discovered the neuronal identity and mechanism underlying one of these circuits: an oscillator that controls the rhythmic back-and-forth sweeping of tactile whiskers, or whisking, in mice. This is the first time that any such oscillator has been fully characterized in mammals.

The MIT team found that the whisking oscillator consists of a population of inhibitory neurons in the brainstem that fires rhythmic bursts during whisking. As each neuron fires, it also inhibits some of the other neurons in the network, allowing the overall population to generate a synchronous rhythm that retracts the whiskers from their protracted positions.

"We have defined a mammalian oscillator molecularly, electrophysiologically, functionally, and mechanistically," says Fan Wang, an MIT professor of brain and cognitive sciences and a member of MIT's McGovern Institute for Brain Research. "It's very exciting to see a clearly defined circuit and mechanism of how rhythm is generated in a mammal."

Wang is the senior author of the study, which appears today in Nature. The lead authors of the paper are MIT research scientists Jun Takatoh and Vincent Prevosto.

Rhythmic behavior

Most of the research that clearly identified central oscillator circuits has been done in invertebrates. For example, Eve Marder's lab at Brandeis University found cells in the stomatogastric ganglion in lobsters and crabs that generate oscillatory activity to control rhythmic motion of the digestive tract.

Characterizing oscillators in mammals, especially in awake behaving animals, has proven to be highly challenging. The oscillator that controls walking is believed to be distributed throughout the spinal cord, making it difficult to precisely identify the neurons and circuits involved. The oscillator that generates rhythmic breathing is located in a part of the brain stem called the pre-Bötzinger complex, but the exact identity of the oscillator neurons is not fully understood.

"There haven't been detailed studies in awake behaving animals, where one can record from molecularly identified oscillator cells and manipulate them in a precise way," Wang says.

Whisking is a prominent rhythmic exploratory behavior in many mammals, which use their tactile whiskers to detect objects and sense textures. In mice, whiskers extend and retract at a frequency of about 12 cycles per second. Several years ago, Wang's lab set out try to identify the cells and the mechanism that control this oscillation.

To find the location of the whisking oscillator, the researchers traced back from the motor neurons that innervate whisker muscles. Using a modified rabies virus that infects axons, the researchers were able to label a group of cells presynaptic to these motor neurons in a part of the brainstem called the vibrissa intermediate reticular nucleus (vIRt). This finding was consistent with previous studies showing that damage to this part of the brain eliminates whisking.

The researchers then found that about half of these vIRt neurons express a protein called parvalbumin, and that this subpopulation of cells drives the rhythmic motion of the whiskers. When these neurons are silenced, whisking activity is abolished.

Next, the researchers recorded electrical activity from these parvalbumin-expressing vIRt neurons in brainstem in awake mice, a technically challenging task, and found that these neurons indeed have bursts of activity only during the whisker retraction period. Because these neurons provide inhibitory synaptic inputs to whisker motor neurons, it follows that rhythmic whisking is generated by a constant motor neuron protraction signal interrupted by the rhythmic retraction signal from these oscillator cells.

"That was a super satisfying and rewarding moment, to see that these cells are indeed the oscillator cells, because they fire rhythmically, they fire in the retraction phase, and they're inhibitory neurons," Wang says.

"New principles"

The oscillatory bursting pattern of vIRt cells is initiated at the start of whisking. When the whiskers are not moving, these neurons fire continuously. When the researchers blocked vIRt neurons from inhibiting each other, the rhythm disappeared, and instead the oscillator neurons simply increased their rate of continuous firing.

This type of network, known as recurrent inhibitory network, differs from the types of oscillators that have been seen in the stomatogastric neurons in lobsters, in which neurons intrinsically generate their own rhythm.

"Now we have found a mammalian network oscillator that is formed by all inhibitory neurons," Wang says.

The MIT scientists also collaborated with a team of theorists led by David Golomb at Ben-Gurion University, Israel, and David Kleinfeld at the University of California at San Diego. The theorists created a detailed computational model outlining how whisking is controlled, which fits well with all experimental data. A paper describing that model is appearing in an upcoming issue of Neuron.

Wang's lab now plans to investigate other types of oscillatory circuits in mice, including those that control chewing and licking.

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Discovery and naming of Africa's oldest known dinosaur

An international team of paleontologists led by Virginia Tech has discovered and named a new, early dinosaur. The skeleton -- incredibly, mostly intact -- was first found by a graduate student in the Virginia Tech Department of Geosciences and other paleontologists over the course of two digs, in 2017 and 2019.

The findings of this new sauropodomorph -- a long-necked dinosaur -- newly named Mbiresaurus raathi were been published today in the journal Nature. The skeleton is, thus far, the oldest dinosaur skeleton ever found in Africa. The animal is estimated to have been 6 feet long with a long tail. It weighed anywhere from 20 to 65 pounds.The skeleton, missing only some of the hand and portions of the skull, was found in northern Zimbabwe.

"The discovery of Mbiresaurus raathi fills in a critical geographic gap in the fossil record of the oldest dinosaurs and shows the power of hypothesis-driven fieldwork for testing predictions about the ancient past," said Christopher Griffin, who graduated in 2020 with a Ph.D. in geosciences from the Virginia Tech College of Science.

Griffin added, "These are Africa's oldest-known definitive dinosaurs, roughly equivalent in age to the oldest dinosaurs found anywhere in the world. The oldest known dinosaurs -- from roughly 230 million years ago, the Carnian Stage of the Late Triassic period -- are extremely rare and have been recovered from only a few places worldwide, mainly northern Argentina, southern Brazil, and India."

Sterling Nesbitt, associate professor of geosciences, also is an author on the study. "Early dinosaurs like Mbiresaurus raathi show that the early evolution of dinosaurs is still being written with each new find and the rise of dinosaurs was far more complicated than previously predicted," he said.

The international team at the heart of this discovery include paleontologists fromtheNational Museums and Monuments of Zimbabwe, the Natural History Museum of Zimbabwe, and Universidade de São Paulo, São Paulo, Brazil.

Finding Mbiresaurus raathi and other fossils

Found alongside Mbiresaurus were an assortment of Carnian-aged fossils, including a herrerasaurid dinosaur, early mammal relatives such as cynodonts, armored crocodylian relatives such as aetosaurs, and, in Griffin's description, "bizarre, archaic reptiles" known as rhynchosaurs, again typically found in South America and India from this same time period.

(Mbiresaurus is derived from Shona and ancient Greek roots. "Mbire" is the name of the district where the animal was found and also is the name of an historic Shona dynasty that ruled the region. The name "raathi" is in honor of Michael Raath, a paleontologist who first reported fossils in northern Zimbabwe.)

From their findings, Mbiresaurus stood on two legs and its head was relatively small head like its dinosaur relatives. It sported small, serrated, triangle-shaped teeth, suggesting that it was an herbivore or potentially omnivore.

Part of the 2019 expedition team in Harare, capital of Zimbabwe, before fieldwork. Left to right: Kudzie Madzana, Edward Mbambo, Sterling Nesbitt, George Malunga, Christopher Griffin, Darlington Munyikwa.

"We never expected to find such a complete and well-preserved dinosaur skeleton," said Griffin, now a post-doctorate researcher at Yale University. "When I found the femur of Mbiresaurus, I immediately recognized it as belonging to a dinosaur and I knew I was holding the oldest dinosaur ever found in Africa. When I kept digging and found the left hip bone right next to the left thigh bone, I had to stop and take a breath -- I knew that a lot of the skeleton was probably there, still articulated together in life position."

Nesbitt, who is a member of the Virginia Tech Global Change Center, part of the Fralin Life Sciences Institute, added, "Chris did an outstanding job figuring out a place to test his ideas about early dinosaur evolution, went there, found incredible fossils, and put it all together in a fantastic collaboration that he initiated."

A theory on dinosaur dispersal

In addition to the discovery of Mbiresaurus, the group of researchers also have a new theory on dinosaur migration, including the when and where.

Africa, like all continents, was once part of the supercontinent called Pangea. The climate across Pangea is thought to have been divided into strong humid and arid latitudinal belts, with more temperate belts spanning higher latitudes and intense deserts across the lower tropics of Pangea. Scientists previously believed that these climate belts influenced and constrained animal distribution across Pangea, said Griffin.

"Because dinosaurs initially dispersed under this climatic pattern, the early dispersal of dinosaurs should therefore have been controlled by latitude," Griffin said. "The oldest dinosaurs are known from roughly the same ancient latitudes along the southern temperate climate belt what was at the time, approximately 50 degrees south."

Griffin and others from the Paleobiology and Geobiology Research Group at Virginia Tech purposefully targeted northern Zimbabwe as the country fell along this same climate belt, bridging a geographic gap between southern Brazil and India during the Late Triassic Age.

More so, these earliest dinosaurs were restricted by climatic bands to southern Pangea, and only later in their history dispersed worldwide. To bolster this claim, the research team developed a novel data method of testing this hypothesis of climatic dispersal barriers based on ancient geography and the dinosaurian family tree. The breakdown of these barriers, and a wave of northward dispersal, coincided with a period of intense worldwide humidity, or the Carnian Pluvial Event.

After this, barriers returned, mooring the now-worldwide dinosaurs in their distinct provinces across Pangea for the remainder of the Triassic Period, according to the team. "This two-pronged approach combines hypothesis-driven predictive fieldwork with statistical methods to independently support the hypothesis that the earliest dinosaurs were restricted by climate to just a few areas of the globe," Griffin said.

Brenen Wynd, also a doctoral graduate of the Department of Geosciences, helped build the data model. "The early history of dinosaurs was a critical group for this kind of problem. Not only do we have a multitude of physical data from fossils, but also geochemical data that previously gave a really good idea of when major deserts were present," he said. "This is the first time where those geochemical and fossil data have been supported using only evolutionary history and the relationships between different dinosaur species, which is very exciting."

A boon for Zimbabwe and Virginia Tech paleontology

The unearthing of one of the earliest dinosaurs ever found -- and most of it fully intact -- is a major win for the Natural History Museum of Zimbabwe. "The discovery of the Mbiresaurus is an exciting and special find for Zimbabwe and the entire paleontological field," said Michel Zondo,a curator and fossil preparer at the museum. "The fact that the Mbiresaurus skeleton is almost complete, makes it a perfect reference material for further finds. It is the first sauropodomorph find of its size from Zimbabwe, otherwise most of our sauropodomorph finds from here are usually of medium- to large-sized animals."

Darlington Munyikwa, deputy executive director of the National Museums and Monuments of Zimbabwe, added,"The unfolding fossil assemblage from the Pebbly Arkose Formation in the Cabora Bassa Basin, which was hitherto known for paucity of animal fossils, is exciting. A number of fossil sites [are] waiting for future exploration were recorded, highlighting the potential of the area to add more valuable scientific material."

Much of the Mbiresaurus specimen is being kept in Virginia Tech's Derring Hall as the skeleton is cleaned and studied. All of the Mbiresaurus skeleton and the additional found fossilswill be permanently kept at Natural History Museum of Zimbabwe in Bulawayo, Zimbabwe.

"This is such an exciting and important dinosaur find for Zimbabwe, and we have been watching the scientific process unfold with great pride,"saidMoira Fitzpatrick, the museum's director. She was not involved in the study. "It has been a pleasure to work with Dr. Griffin,and we hope the relationship will continue well into the future."

The discovery of Mbiresaurus also marks another highpoint for the Paleobiology and Geobiology Research Group. In 2019, Nesbitt authored a paper detailing the newly named tyrannosauroid dinosaur Suskityrannus hazelae. Incredibly, Nesbitt discovered the fossil at age 16 as a high school student participating in a dig expedition in New Mexico in 1998.

"Our group seeks out equal partnerships and collaborations all over the world and this project demonstrates a highly successful and valued collaboration," Nesbitt said. "We will continue studying the many fossils from the same areas as where the new dinosaur came from and explore the fossil beds further."

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ALMA discovers birth cry from a baby star in the Small Magellanic Cloud

Researchers at Osaka Metropolitan University have observed "baby stars" in the Small Magellanic Cloud, having an environment similar to the early universe. Toward one of the baby stars, they found molecular outflow, which has similar properties to those seen in the Milky Way galaxy, giving a new perspective on the birth of stars.

The heavy elements in interstellar matter significantly impact the mechanism of star formation. In the early universe, the abundance of heavy elements was lower than in the present universe because there was not enough time for nucleosynthesis to produce heavy elements in stars. It has not been well understood how star formation in such an environment differs from present-day star formation.

An international team led by Professor Toshikazu Onishi, Osaka Metropolitan University, and Project Assistant Professor Kazuki Tokuda, Kyushu University/NAOJ, used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe high-mass young stellar objects in the Small Magellanic Cloud.

The Small Magellanic Cloud is characterized by a low abundance of elements heavier than helium, similar to the galaxies 10 billion years ago. The target provides a detailed observational view thanks to the relatively close distance from Earth. In this study, researchers detected a bipolar gas stream flowing out of the "baby star" Y246 and determined that the molecular flow has a velocity of more than 54,000 km/h in both directions.

In the present universe, growing "baby stars" are thought to have their rotational motion suppressed by this molecular outflow during gravitational contraction, accelerating the star growth. The discovery of the same phenomenon in the Small Magellanic Cloud suggests that this process of star formation has been common throughout the past 10 billion years. The team also expects this discovery to bring new perspectives to studying stars and planet formation.

From Science Daily

ALMA witnesses deadly star-slinging tug-of-war between merging galaxies

While observing a newly-dormant galaxy using the Atacama Large Millimeter/submillimeter Array (ALMA) and the Hubble Space Telescope (HST), scientists discovered that it had stopped forming stars not because it had used up all of its gas but because most of its star-forming fuel had been thrown out of the system as it merged with another galaxy. The result is a first for ALMA scientists. What's more, if proven common, the results could change the way scientists think about galaxy mergers and deaths. The results of the research are published in The Astrophysical Journal Letters.

As galaxies move through the Universe, they sometimes encounter other galaxies. As they interact, each galaxy's gravity pulls on the other. The ensuing tug-of-war flings gas and stars away from the galaxies, leaving behind streams of material known as tidal tails.

And that's just what scientists believe happened to SDSS J1448+1010, but with a plot twist. The massive galaxy, which was born when the Universe was about half its current age, has nearly completed merging with another galaxy. During observations with the HST and ALMA -- an international collaboration in which the U.S. National Science Foundation's National Radio Astronomy Observatory (NRAO) is a partner -- scientists discovered tidal tails containing roughly half of the entire system's cold, star-forming gas. The discovery of the forcefully discarded material -- equal to 10 billion times the mass of Earth's Sun -- was an indication that the merger may be responsible for snuffing out star formation, and that's something scientists didn't expect.

"What initially made this massive galaxy interesting was that, for some reason, it suddenly stopped forming stars about 70 million years ago immediately following a burst of star-forming activity. Most galaxies are happy to just keep forming stars," said Justin Spilker, an astronomer at Texas A&M University and the lead author of the paper. "Our observations with ALMA and Hubble proved that the real reason the galaxy stopped forming stars is that the merger process ejected about half the gas fuel for star formation into intergalactic space. With no fuel, the galaxy couldn't keep forming stars."

The discovery is shedding light on the processes by which galaxies live or die, and helping scientists to better understand their evolution.

"When we look out at the Universe, we see some galaxies that are actively forming new stars, like our own Milky Way, and some that aren't. But those 'dead' galaxies have many old stars in them, so they must have formed all of those stars at some point and then stopped making new ones," said Wren Suess, a cosmology fellow at the University of California Santa Cruz and a co-author of the paper. "We still don't yet understand all of the processes that make galaxies stop forming stars, but this discovery shows just how powerful these major galaxy mergers are, and how much they can affect how a galaxy grows and changes over time."

Because the new result is from a single observation, it is currently unclear just how common this tug-of-war and its resultant quiescence may be. However, the discovery challenges long-held theories about exactly how star formation stops and galaxies die and has provided scientists with an exciting new challenge: to find more examples.

"While it's pretty clear from this system that cold gas really can end up way outside of a merger system that shuts off a galaxy, the sample size of one galaxy tells us very little about how common this process is," said David Setton, a graduate student in the department of physics and astronomy at the University of Pittsburgh and a co-author of the paper. "But, there are many galaxies out there like J1448+1010 that we're able to catch right in the middle of those crashes and study exactly what happens to them when they go through that stage. The ejection of cold gas is an exciting new piece of the quiescence puzzle, and we're excited to try to find more examples of this."

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Dolphins form largest alliance network outside humans, study finds

Male bottlenose dolphins form the largest known multi-level alliance network outside humans, an international team led by researchers at the University of Bristol have shown. These cooperative relationships between groups increase male access to a contested resource.

The scientists, with colleagues from the University of Zurich and University of Massachusetts, analysed association and consortship data to model the structure of alliances between 121 adult male Indo-Pacific bottlenose dolphins at Shark Bay in Western Australia. Their findings have been published today in The Proceedings of the National Academy of Sciences (PNAS).

Male dolphins in Shark Bay form first-order alliances of two-three males to cooperatively pursue consortships with individual females. Second-order alliances of four-14 unrelated males compete with other alliances over access to female dolphins and third-order alliances occur between cooperating second-order alliances.

Co-lead author Dr Stephanie King, Associate Professor from Bristol's School of BiologicalSciences explained: "Cooperation between allies is widespread in human societies and one of the hallmarks of our success. Our capacity to build strategic, cooperative relationships at multiple social levels, such as trade or military alliances both nationally and internationally, was once thought unique to our species.

"Not only have we shown that male bottlenose dolphins form the largest known multilevel alliance network outside humans, but that cooperative relationships between groups, rather than simply alliance size, allows males to spend more time with females, thereby increasing their reproductive success."

Dr Simon Allen, Senior Lecturer at Bristol's School of Biological Sciences, who contributed to the study, said "We show that the duration over which these teams of male dolphins consort females is dependent upon being well-connected with third-order allies, that is, social ties between alliances leads to long-term benefits for these males."

Intergroup cooperation in humans was thought to be unique and dependent upon two other features that distinguish humans from our common ancestor with chimpanzees, the evolution of pair bonds and parental care by males. "However, our results show that intergroup alliances can emerge without these features, from a social and mating system that is more chimpanzee like" noted Richard Connor, Professor Emeritus at the University of Massachusetts and now affiliated with Florida International University, who co-led the study with Dr King.

The publication of the importance of third level or intergroup alliances in dolphins in 2022 holds special significance as the team celebrate the 40th anniversary of the start of Shark Bay dolphin research in 1982 and the 30th anniversary of the publication in 1992 of their discovery of two levels of male alliance formation, also published in The Proceedings of the National Academy of Sciences.

Professor Dr. Michael Krützen, an author on the study and Head of the Anthropology Institute at the University of Zurich, added; "It is rare for non-primate research to be conducted from an anthropology department, but our study shows that important insights about the evolution of characteristics previously thought to be uniquely human can be gained by examining other highly social, large-brained taxa."

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Inside the head of one of Australia's smallest fossil crocs

Approximately 13.5 million years ago, north-west Queensland was home to an unusual and particularly tiny species of crocodile and now scientists are unlocking its secrets.

University of Queensland researchers have used state-of-the-art technology to reveal previously unknown details about the prehistoric Trilophosuchus rackhami's anatomy.

Faculty of Science PhD candidate, Jorgo Ristevski said it is the most detailed examination ever undertaken of the skull anatomy of an extinct croc from Australia.

"By micro-CT scanning the beautifully preserved skull, we were able to digitally separate each bone," Mr Ristevski said.

"We estimated that at adulthood, Trilophosuchus rackhami would have been between 70 and 90 centimetres long and weigh one to two kilograms, which was very small compared to most present-day crocs.

"This was a truly unique looking croc, with a short snout and three distinct ridges on the top of its skull."

Trilophosuchus rackhami means Rackham's three-crested croc, which was named in 1993 in honour of Alan Rackham, who now manages the Riversleigh Fossil Discovery Centre at Mt Isa.

Mr Ristevski said palaeoneurology, a field that studies the brain and nervous system of fossil species, can provide crucial insights into the animal's evolution, morphology and even behaviour.

"For one of the studies, I digitally reconstructed the brain cavity of Trilophosuchus rackhami and found that it resembles that of some distantly related and potentially terrestrial extinct crocs from Africa and South America," Mr Ristevski said.

"We were quite surprised to find this because evolutionarily speaking, Trilophosuchus rackhami is more closely related to today's crocs.

"This may indicate that Trilophosuchus rackhami spent more time on land than most living crocs."

Mr Ristevski said the findings would be useful in interpreting the evolutionary relationships of extinct crocs, something that will be researched in the future.

Associate Professor Steve Salisbury said up until very recently, Australia had an amazing diversity of prehistoric crocs.

"Trilophosuchus rackhami was certainly one of the cutest," he said.

"If we could travel back in time to north Queensland 13 million years ago, not only would you need to watch out for crocodiles at the water's edge, but you'd also have to make sure you didn't step on them in the forest."

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Team developing oral insulin tablet sees breakthrough results

A team of University of British Columbia researchers working on developing oral insulin tablets as a replacement for daily insulin injections have made a game-changing discovery.

Researchers have discovered that insulin from the latest version of their oral tablets is absorbed by rats in the same way that injected insulin is.

"These exciting results show that we are on the right track in developing an insulin formulation that will no longer need to be injected before every meal, improving the quality of life, as well as mental health, of more than nine million Type 1 diabetics around the world." says professor Dr. Anubhav Pratap-Singh (he/him), the principal investigator from the faculty of land and food systems.

He explains the inspiration behind the search for a non-injectable insulin comes from his diabetic father who has been injecting insulin 3-4 times a day for the past 15 years.

According to Dr. Alberto Baldelli (he/him), a senior fellow in Dr. Pratap-Singh's lab, they are now seeing nearly 100 per cent of the insulin from their tablets go straight into the liver. In previous attempts to develop a drinkable insulin, most of the insulin would accumulate in the stomach.

"Even after two hours of delivery, we did not find any insulin in the stomachs of the rats we tested. It was all in the liver and this is the ideal target for insulin -- it's really what we wanted to see," says Yigong Guo (he/him), first author of the study and a PhD candidate working closely on the project.

Changing the mode of delivery

When it comes to insulin delivery, injections are not the most comfortable or convenient for diabetes patients. But with several other oral insulin alternatives also being tested and developed, the UBC team worked to solve where and how to facilitate a higher absorption rate.

Dr. Pratap-Singh's team developed a different kind of tablet that isn't made for swallowing, but instead dissolves when placed between the gum and cheek.

This method makes use of the thin membrane found within the lining of the inner cheek and back of the lips (also known as the buccal mucosa). It delivered all the insulin to the liver without wasting or decomposing any insulin along the way.

"For injected insulin we usually need 100iu per shot. Other swallowed tablets being developed that go to the stomach might need 500iu of insulin, which is mostly wasted, and that's a major problem we have been trying to work around," Yigong says.

Most swallowed insulin tablets in development tend to release insulin slowly over two to four hours, while fast-release injected insulin can be fully released in 30-120 minutes.

"Similar to the rapid-acting insulin injection, our oral delivery tablet absorbs after half an hour and can last for about two to four hours long," says Dr. Baldelli.

Potential broad benefits

The study is yet to go into human trials, and for this to happen Dr. Pratap-Singh says they will require more time, funding and collaborators. But beyond the clear potential benefits to diabetics, he says the tablet they are developing could also be more sustainable, cost-effective and accessible.

"More than 300,000 Canadians have to inject insulin multiple times per day," Dr. Pratap-Singh says. "That is a lot of environmental waste from the needles and plastic from the syringe that might not be recycled and go to landfill, which wouldn't be a problem with an oral tablet."

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Discovery of the oldest visible planetary Nebula hosted by a 500-million-year-old Galactic cluster -- a rare beauty with a hot blue heart

An international team of astronomers led by members of the Laboratory for Space Research (LSR) and Department of Physics at The University of Hong Kong (HKU), have discovered a rare celestial jewel-a so-called Planetary Nebula (PN) inside a 500 million-year-old Galactic Open Cluster (OC) called M37 (also known as NGC2099). This is a very rare finding of high astrophysical value. Their findings have just been published in the open-access paper Astrophysical Journal Letters.

PNe are the ejected, glowing shrouds of dying stars that shine with a rich emission line spectrum and display, as a result, their distinct colours and shapes that make them photogenic magnets for public interest. It was no coincidence that one of the first James Webb Space Telescope (the largest optical telescope in space) images released to the public was a PN.

The PN, with the rather ungainly name of "IPHASX J055226.2+323724," is only the third example of an association between a PN and an OC out of the ~4,000 PNe known in our Galaxy. It also appears to be the oldest PN ever found. The small team led by Professor Quentin PARKER, Director of the HKU LSR, have determined some interesting properties for their discovery: the authors found the PN has a "kinematic age" of 70,000 years. This estimate is based on how fast the nebula is expanding, as determined from the PN emission lines, and assuming this speed has remained effectively the same since the beginning, and is the time elapsed since the nebular shell was first ejected by the host, a dying star. This compares to typical PN ages of 5,000-25,000 years. It is truly a grand old dame in PN terms but of course a mere "blink of the eye" in terms of the life of the original star itself that runs to hundreds of millions of years.

Because this "grand old dame" lives in a stellar cluster, this environment enables the team to determine powerful additional parameters not possible for the general Galactic PN population. These include estimating the mass of the PN's progenitor star when it turned off the stellar main sequence, as derived from the observed properties of the thousands of stars in the cluster when plotted in a so-called colour-magnitude diagram. The team can also estimate the residual mass of the central star that ejected the PNe via theoretical isochrones and observed properties of the hot, blue central star. As a result, they figured how massive the star was that ejected the PN gaseous shell when it was born and how much mass is now left in its residual, contracting hot core (which is already a so-called 'White Dwarf' star). Fresh "Gaia" data for the hot blue, PN central star also provide a good distance estimate allowing the PN's actual size at this extreme age to be determined as 3.2pc (parsec, an astronomical unit of measure for interstellar space with 1pc equals to 3.26 light-years) in diameter -- unsurprisingly perhaps also at the extreme end of known PN physical sizes.

Former HKU PhD student Dr Vasiliki FRAGKOU, the first author of the study stated, "I am so excited to be able to work on these fascinating rare cases of OC-PN associations because they keep turning up important science results, like all three cases we have found are butterfly (bi-polar) PN in terms of shape, all are very faint and highly evolved, and all have Type-I chemistry according to their emission lines, and of course all have intermediate to high progenitor masses."

Corresponding author Professor Quentin Parker said, "This is only the third example of a PN found in a Galactic open star cluster, and my group has found all three confirmed examples. They are incredibly rare but also very important as these beautiful objects allow us to independently determine points on the so called initial to final mass relation (IFMR) for stars -- an important astrophysical relation -- independent of the traditional method of using white dwarfs in clusters. Intriguingly, all our points lie just below the empirical IFMR trend currently established but add to the "kink" in this relation found recently in the 2-3 Solar mass range for the original progenitor mass by Marigo et al in the Nature Astronomy journal. Our OC-PN points fortuitously are found in currently sparsely populated regions of the IFMR, making them even more valuable."

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X-shaped radio galaxies might form more simply than expected

When astronomers use radio telescopes to gaze into the night sky, they typically see elliptical-shaped galaxies, with twin jets blasting from either side of their central supermassive black hole. But every once in a while -- less than 10% of the time -- astronomers might spot something special and rare: An X-shaped radio galaxy, with four jets extending far into space.

Although these mysterious X-shaped radio galaxies have confounded astrophysicists for two decades, a new Northwestern University study sheds new insight into how they form -- and its surprisingly simple. The study also found that X-shaped radio galaxies might be more common than previously thought.

The study will be published on Aug. 29 in the Astrophysical Journal Letters. It marks the first large-scale galaxy accretion simulation that tracks the galactic gas far from the supermassive black hole all the way toward it.

Simple conditions lead to messy result

Using new simulations, the Northwestern astrophysicists implemented simple conditions to model the feeding of a supermassive black hole and the organic formation of its jets and accretion disk. When the researchers ran the simulation, the simple conditions organically and unexpectedly led to the formation of an X-shaped radio galaxy.

Surprisingly, the researchers found that the galaxy's characteristic X-shape resulted from the interaction between the jets and the gas falling into the black hole. Early in the simulation, the infalling gas deflected the newly formed jets, which turned on and off, erratically wobbled and inflated pairs of cavities in different directions to resemble an X-shape. Eventually, however, the jets became strong enough to push through the gas. At this point, the jets stabilized, stopped wobbling and propagated along one axis.

"We found that even with simple symmetric initial conditions, you can have quite a messy result," said Northwestern's Aretaios Lalakos, who led the study. "A popular explanation of X-shaped radio galaxies is that two galaxies collide, causing their supermassive black holes to merge, which changes the spin of the remnant black hole and the direction of the jet. Another idea is that the jet's shape is altered as it interacts with large-scale gas enveloping an isolated supermassive black hole. Now, we have revealed, for the first time, that X-shaped radio galaxies can, in fact, be formed in a much simpler way."

Lalakos is a graduate student in Northwestern's Weinberg College of Arts and Sciences and a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He is co-advised by paper coauthor Sasha Tchekhovskoy, an assistant professor of physics and astronomy at Northwestern and key member of CIERA, and Ore Gottlieb, a CIERA postdoctoral fellow.

An accidental X-shape

Although radio galaxies emit visible light, they also encompass large regions of radio emission. Perhaps the most famous radio galaxy is M87, one of the most massive galaxies in the universe, which was further popularized in 2019 when the Event Horizon Telescope imaged its central supermassive blackhole. First coined in 1992, X-shaped radio galaxies make up less than 10% of all radio galaxies.

When Lalakos set out to model a black hole, he did not expect to simulate an X-shaped galaxy. Instead, he aimed to measure the amount of mass eaten by a black hole. He inputted simple astronomical conditions into the simulation and let it run. Lalakos did not initially recognize the importance of the emerging X-shape, but Tchekhovskoy reacted with enthusiastic fervor.

"He said, 'Dude, this is very important! This is an X-shape!'" Lalakos said. "He told me that astronomers have observed this in real life and didn't know how they formed. We created it in a way that no one had even speculated before."

In previous simulations, other astrophysicists have attempted to create X-shaped structures artificially in order study how they arise. But Lalakos' simulation organically led to the X-shape.

"In my simulation, I tried to assume nothing," Lalakos said. "Usually, researchers put a black hole in the middle of a simulation grid and place a large, already-formed gaseous disk around it, and then they may add ambient gas outside the disk. In this study, the simulation starts without a disk, but soon one forms as the rotating gas gets closer to the black hole. This disk then feeds the black hole and creates jets. I made the simplest assumptions possible, so the whole outcome was a surprise. This is the first time anyone has seen X-shaped morphology in simulations from very simple initial conditions."

'Not lucky enough to see them'

Because the X-shape only emerged early in the simulation -- until the jets strengthened and stabilized -- Lalakos believes X-shaped radio galaxies might appear more frequently, but last a very short time, in the universe than previously thought.

"They might arise every time the black hole gets new gas and starts eating again," he said. "So they might be happening frequently, but we might not be lucky enough to see them because they only happen for as long as the power of the jet is too weak to push the gas away."

Next, Lalakos plans to continue running simulations to better understand how these X-shapes arise. He looks forward to experimenting with the size of the accretion disks and spins of central black holes. In other simulations, Lalakos included accretion disks that were almost non-existent all the way up to extremely large -- none led to the elusive X-shape.

"For most of the universe, it's impossible to zoom in right at the center and see what's happening very near a black hole," Lalakos said. "And even the things we can observe, we are constrained by time. If the supermassive black hole is already formed, we cannot observe its evolution because human lifetime is too short. In most cases, we rely on simulations to understand what happens near a black hole."

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Getting data to do more for biodiversity

Michigan State University ecologists have developed a mathematical framework that could help monitor and preserve biodiversity without breaking the bank.

This framework or model takes low-cost data about relatively abundant species in a community and uses it to generate valuable insights on their harder-to-find neighbors. The journal Conservation Biology published the research as an Early View article on Aug. 25.

"One of the biggest challenges in monitoring biodiversity is that the species you're most concerned about tend to be lowest in abundance or they're the hardest species to observe during data collection," said Matthew Farr, the lead author on the new report. "This model can be really helpful for those rare and elusive species."

Farr, now a postdoctoral researcher at the University of Washington, helped develop the model as a doctoral student in Elise Zipkin's Quantitative Ecology Lab in the College of Natural Science at MSU.

"There are a lot of species in the world and many of them are data deficient," said Zipkin, an associate professor of integrative biology and director of MSU's Ecology, Evolution and Behavior Program, or EEB. "We're developing approaches to more quickly estimate what's going on with biodiversity, which species are in trouble and where, spatially, do we need to focus our conservation efforts."

After validating the model with an assist from forest-dwelling antelope in Africa, the researchers say it could be applied to a variety of other animals that meet certain criteria.

"The model doesn't work for all types of species. It's not a panacea," Zipkin said. "But when it does work for a community, we can learn a lot more about member species without much data."

The 'magic' of the model

For its newest model, Zipkin's team focused on what's called detection-nondetection data that tracks whether or not a given animal is detected in a given habitat.

"It's basically the cheapest data and the easiest to collect," Zipkin said. "You go to a spot, wait and see what animals are there and only need to record which species are seen."

Researchers gather this data visually in person or with low-cost, motion-detecting camera traps that snap photos when triggered by an animal. Researchers then analyze the photos to record detection-nondetection data over time.

There are trade-offs, though. Although relatively cheap and easy to collect, detection-nondetection data doesn't provide as much information as researchers and conservationists want. Historically, that has required intensive observational approaches such as tagging and tracking animals.

"That lets us calculate all sorts of things about the animals and their communities, but that data is expensive and hard to get," Zipkin said. "For certain species, it's impossible."

The MSU team realized that, for the right animals, they could use an understanding of animal behavior and statistics to close the information gap by squeezing more insight out of detection-nondetection data.

"For some species, these are the best data you can get," Farr said. "Now we can get more out of it."

That may sound like magic -- some of Zipkin's colleagues have even said so -- ?but there's nothing supernatural about the model. Like much of science, it's the result of hard work, collaboration and building on previous efforts in the field.

The story of the new model has its roots in 2003 with researchers J. Andrew Royle and James D. Nichols. The duo devised a mathematical link between the abundance of a species and the probability of detecting it.

At the time, Royle was a researcher with the U.S. Fish and Wildlife Service and Nichols was with the U.S. Geological Survey. Both are MSU alumni: Royle graduated with his bachelor's degree in 1990 and Nichols earned his doctorate in 1976.

"It's interesting," said Farr, whose current adviser, Sarah Converse, also graduated with a bachelor's degree from Michigan State before becoming an associate professor at the University of Washington. "Wherever you go in this field, people have some connection to Michigan State."

After publishing the Royle-Nichols model, Royle joined the USGS, where he'd work with Zipkin before she joined MSU in 2014. In 2016, Zipkin's team evolved the Royle-Nichols model to estimate things like the survival and reproduction rates for a single species using the barred owl as a case study.

Working in Zipkin's lab with support from the National Science Foundation, Farr took the next step by linking the population dynamics of different species within the same communities.

"The model lets information from more common species inform what's happening with the rare and elusive species," said Farr. "The model relies on the commonalities between species, but still allows for variations."

To develop the model, the team had to make some assumptions, like that the target species were territorial and did not travel much. The researchers then had to find real species that fit those assumptions to validate their model.

"We knew it would work for certain types of communities, but did those communities exist in real life?" Zipkin said.

"That's one of the biggest challenges in model development," Farr said. "You develop the model in a vacuum with simulations running under perfect conditions. You need to show what it can do in a real-world situation."

"That's when Tim O'Brien reached out and said, 'I have your animals,'" Zipkin said.

The duiker data

Timothy O'Brien is a retired ecologist in Kenya who worked with the Wildlife Conservation Society, a nongovernmental organization or NGO, and an expert in camera traps. As part of what's known as the Tropical Ecology Assessment and Monitoring program, or TEAM, he's helped standardize how camera traps are used to make their data as powerful as possible.

He was familiar with Zipkin's 2016 work and learned that she was expanding the model to include multiple species over multiple seasons. He suspected that forest-dwelling antelopes, notably those known as duiker, would provide the perfect test case.

Not only did duiker behavior match the assumptions of the model, but O'Brien had been helping monitor the animals for years using camera traps. Duikers presented an interesting and important conservation case.

"The duiker that live in rainforests, they are the most sought-after bushmeat in Africa," O'Brien said. "If duiker populations are in decline, it's usually because of people hunting for bushmeat."

Bushmeat is meat from any wild animal and it's an important source of food and income for many communities. But the hunting is loosely regulated and is financially incentivized by markets that sell bushmeat. The combination can be devastating for duiker populations.

With MSU's model and TEAM's duiker data, the team assessed the population dynamics of a total of 12 antelope species -- some more abundant than others -- in six national parks in Africa, where duikers are protected. The data covered time periods ranging from four to 11 years.

"We didn't see the level of population decline in duiker you expect to see when hunting is an issue," O'Brien said. "I would say the parks are fulfilling their function as far as duiker are concerned."

Overall, the duiker populations were mostly stable, but the researchers did detect population declines in about 20% of the combinations of species and parks that they examined. Again, the declines weren't so substantial to suggest that the duiker were being overhunted in the parks, but the researchers still want to understand what's happening in those cases.

"We found that's what causing the changes was more the differences between the parks than between the species," Zipkin said. "We haven't pinpointed the exact causes yet, but our results could help us do that."

"Matt and Elise have taken this model to a whole new plane," O'Brien said. "I've really enjoyed the collaboration."

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