“Earth-like planets in the habitable zone — the region around a star where temperatures could allow liquid water to exist — can easily be up to a billion times dimmer than their host star,” said research team leader Nico Deshler from the University of Arizona. “This makes them difficult to detect because their faint light is overwhelmed by the star’s brightness. Our new coronagraph design siphons away starlight that might obscure exoplanet light before capturing an image.”

In Optica, the researchers show that the new coronagraph can theoretically achieve the fundamental limits of exoplanet detection and localization set by quantum optics. They also used it to capture images that allowed them to estimate the position of artificial exoplanets with distances from their host star up to 50 times smaller than what the telescope’s resolution limit would normally allow.

“Compared to other coronagraph designs, ours promises to supply more information about so-called sub-diffraction exoplanets — those which lie below the resolution limits of the telescope,” said Deshler. “This could allow us to potentially detect biosignatures and discover the presence of life among the stars.”

Blinded by the light

Optically analyzing exoplanets poses a formidable challenge because, at astronomical scales, they are often too close to their parent star for current telescopes to resolve. Exoplanets can also be orders of magnitude dimmer than their host star. Although astronomers have developed various ways to indirectly infer the presence of a planet around a prospective star, directly observing exoplanets in images would be ideal.

With NASA’s next-generation space telescope, the Habitable Worlds Observatory (HWO), being dedicated to exoplanet science, many coronagraph designs have emerged, each with different practical and theoretical performance trade-offs. At the same time, recent work has shown that traditional notions of resolution for telescopes do not reflect fundamental limits and can be circumvented with careful optical pre-processing.

Inspired by these developments, the researchers decided to use a spatial mode sorter available in their lab to develop an improved coronagraph that theoretically rejects all the light from an on-axis star while achieving maximal throughput of an off-axis exoplanet.

Much like piano notes emit different acoustic frequencies, light sources in space excite different spatial modes — unique shapes and patterns of oscillation — depending on their position. The researchers separated these different modes using a mode sorter to isolate and eliminate light from a star and an inverse mode sorter to recompose the optical field after the starlight is rejected. This made it possible to capture an image of the exoplanet without the star.

“Our coronagraph directly captures an image of the exoplanet, as opposed to measuring only the quantity of light from the exoplanet without any spatial orientation,” said Deshler. “Images can provide context and composition information that can be used to determine exoplanet orbits and identify other objects that scatter light from a star such as exozodiacal dust clouds.”

Imaging faint exoplanets

After configuring their coronagraph in the lab, the researchers constructed an artificial star-exoplanet scene in which the exoplanet was positioned close enough to the star to be unresolvable with a traditional telescope. The contrast ratio between the star and the planet was set to 1000:1.

The researchers scanned the position of the exoplanet to simulate an orbit where the planet traverses in front of the star and then tried to determine its position in each frame. The images captured with their experimental setup incorporating the new coronagraph allowed them to estimate the position of the exoplanet at sub-diffraction planet-star separations.

The researchers are working to improve the mode sorter to reduce crosstalk, a type of interference in which light leaks across different optical modes. For scenes with moderate contrast levels, crosstalk is not very problematic. However, the extreme contrasts found in exoplanet science would require a very high-fidelity spatial mode sorter to sufficiently isolate light from the star.

The researchers say that this proof-of-principle experiment could inspire further exploration of optical pre-processing with spatial mode sorters in future astronomical instrumentation. For example, the spatial mode filtering methods they used could address more complex scenarios, such as treating stars as extended objects, and may also lead to new imaging methods for quantum sensing, medical imaging and communications.

Scientists at the Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, have worked out the structure of this machine and shown how it operates like the lock on a canal to transport pyruvate — a molecule generated in the body from the breakdown of sugars — into our mitochondria.

Known as the mitochondrial pyruvate carrier, this molecular machine was first proposed to exist in 1971, but it has taken until now for scientists to visualise its structure at the atomic scale using cryo-electron microscopy, a technique used to magnify an image of an object to around 165,000 times its real size. Details are published today in Science Advances.

Dr Sotiria Tavoulari, a Senior Research Associate from the University of Cambridge, who first determined the composition of this molecular machine, said: “Sugars in our diet provide energy for our bodies to function. When they are broken down inside our cells they produce pyruvate, but to get the most out of this molecule it needs to be transferred inside the cell’s powerhouses, the mitochondria. There, it helps increase 15-fold the energy produced in the form of the cellular fuel ATP.”

Maximilian Sichrovsky, a PhD student at Hughes Hall and joint first author of the study, said: “Getting pyruvate into our mitochondria sounds straightforward, but until now we haven’t been able to understand the mechanism of how this process occurs. Using state-of-the-art cryo-electron microscopy, we’ve been able to show not only what this transporter looks like, but exactly how it works. It’s an extremely important process, and understanding it could lead to new treatments for a range of different conditions.”

Mitochondria are surrounded by two membranes. The outer one is porous, and pyruvate can easily pass through, but the inner membrane is impermeable to pyruvate. To transport pyruvate into the mitochondrion, first an outer ‘gate’ of the carrier opens, allowing pyruvate to enter the carrier. This gate then closes, and the inner gate opens, allowing the molecule to pass through into the mitochondrion.

“It works like the locks on a canal but on the molecular scale,” said Professor Edmund Kunji from the MRC Mitochondrial Biology Unit, and a Fellow at Trinity Hall, Cambridge. “There, a gate opens at one end, allowing the boat to enter. It then closes and the gate at the opposite end opens to allow the boat smooth transit through.”

Because of its central role in controlling the way mitochondria operate to produce energy, this carrier is now recognised as a promising drug target for a range of conditions, including diabetes, fatty liver disease, Parkinson’s disease, specific cancers, and even hair loss.

Pyruvate is not the only energy source available to us. Our cells can also take their energy from fats stored in the body or from amino acids in proteins. Blocking the pyruvate carrier would force the body to look elsewhere for its fuel — creating opportunities to treat a number of diseases. In fatty liver disease, for example, blocking access to pyruvate entry into mitochondria could encourage the body to use potentially dangerous fat that has been stored in liver cells.

Likewise, there are certain tumour cells that rely on pyruvate metabolism, such as in some types of prostate cancer. These cancers tend to be very ‘hungry’, producing excess pyruvate transport carriers to ensure they can feed more. Blocking the carrier could then starve these cancer cells of the energy they need to survive, killing them.

Previous studies have also suggested that inhibiting the mitochondrial pyruvate carrier may reverse hair loss. Activation of human follicle cells, which are responsible for hair growth, relies on metabolism and, in particular, the generation of lactate. When the mitochondrial pyruvate carrier is blocked from entering the mitochondria in these cells, it is instead converted to lactate.

Professor Kunji said: “Drugs inhibiting the function of the carrier can remodel how mitochondria work, which can be beneficial in certain conditions. Electron microscopy allows us to visualise exactly how these drugs bind inside the carrier to jam it — a spanner in the works, you could say. This creates new opportunities for structure-based drug design in order to develop better, more targeted drugs. This will be a real game changer.”

The research was supported by the Medical Research Council and was a collaboration with the groups of Professors Vanessa Leone at the Medical College of Wisconsin, Lucy Forrest at the National Institutes of Health, and Jan Steyaert at the Free University of Brussels.

It depends, of course, on whether you’re making a hearty winter stew or getting ready to watch the Super Bowl.

Most scientists agree that categorizing an object — like thinking of a carrot as either a root vegetable or a party snack — is the job of the prefrontal cortex, the brain region responsible for reasoning and other high-level functions that make us smart and social. In that account, the eyes and visual regions of the brain are kind of like a security camera collecting data and processing it in a standardized way before passing it off for analysis.

However, a new study led by biomedical engineer and neuroscientist Nuttida Rungratsameetaweemana, an assistant professor at Columbia Engineering, shows that the brain’s visual regions play an active role in making sense of information. Crucially, the way it interprets the information depends on what the rest of the brain is working on.

If it’s Super Bowl Sunday, the visual system sees those carrots on a veggie tray before the prefrontal cortex knows they exist.

Published April 11 in Nature Communications, the study provides some of the clearest evidence yet that early sensory systems play a role in decision-making — and that they adapt in real-time. It also points to new approaches for designing AI systems that can adapt to new or unexpected situations.

Chromosomal rearrangements where large chunks of chromosomes are inverted, moved, deleted or duplicated, provide a possible source for such large-scale “macromutations.” However, characterizing chromosomal rearrangements with commonly tried DNA sequencing methods has been difficult.

Many organisms, including humans, are diploid, meaning they have two sets of chromosomes — one from each parent. The same is true for stick insects. This makes identifying chromosomal rearrangements with species challenging when assembling genomes.

“In the past, we’ve averaged data from each chromosome set, but the limited accuracy of this method doesn’t tell the whole story,” says Utah State University evolutionary biologist Zachariah Gompert. “Using newer, molecular and computational approaches that generate phased genome assemblies, where the two copies of each chromosome are assembled separately, has enabled us to directly show how complex chromosomal rearrangements have allowed stick insects to adapt by being cryptic on different host plants and thereby avoid predation.”

In the April 18, 2025 online issue of the American Association for the Advancement of Science journal Science, Gompert and colleagues report adaptive divergence in cryptic color pattern is underlain by two distinct, complex chromosomal rearrangements, where millions of bases of DNA were flipped backwards and moved from one part of a chromosome to another, independently in populations of stick insects on different mountains. Contributing authors on the paper include Gompert’s long-time collaborator Patrik Nosil and other researchers from the French National Center for Scientific Research (CNRS), along with scientists from the University of Notre Dame, the University of Nevada, Reno, and The Institute of Cancer Research in the United Kingdom. The research is supported by the National Science Foundation and the European Research Council.

The scientists studied Timema cristinae insects with varied color patterns, collected from two mountains near Santa Barbara, California. The wingless, plant-feeding insects are divergently adapted to two different plant species in the coastal chaparral habitats. One stick insect pattern is green, allowing it to blend in with the California lilac, while the other sports a thin, white stripe on its back making it nearly undetectable among the needle-like leaves of the chamise shrub.

Gompert and colleagues showed this adaptive difference in color pattern is almost completely explained by the presence versus absence of these individual complex, chromosomal rearrangements.

“The new phased genomic assembly technology used in this study was a critical piece in helping us examine how color pattern evolved in these insects,” says Gompert, professor in USU’s Department of Biology and the USU Ecology Center. “Our findings suggest chromosomal rearrangements might be more widespread and more complex than we previously thought.”

He says these mutations, despite being large, are easy to miss using traditional DNA sequencing approaches.

“Chromosomal rearrangements can be difficult to detect and characterize using standard approaches,” Gompert says. “We’re essentially exploring the ‘dark matter’ of the genome.”

Structural variation, he says, rather than being rare, may be regularly available to prompt evolution.

“We’re just scratching the surface,” Gompert says. “We’ve lacked the tools to detect structural variation, but with improved technology we hypothesize it plays a more important role in evolution than previously recognized.”

The earthquake, which killed more than 23,000 people and left about 1.5 million people homeless, took place along the Motagua Fault, at the boundary between the North American and Caribbean tectonic plate boundary.

Severe ground shaking from the 1976 earthquake caused landslides and sediment-laden turbidity currents that can be seen clearly in cores taken from the lakebeds. Normally, researchers might expect that this shaking would produce the thinnest sediment deposits in lakes furthest away from an earthquake, since seismic waves weaken as they travel away from an earthquake epicenter.

But in the Guatemalan lakes, the cores with the thickest sediment traces of the earthquake occur at the end of the fault rupture, said Jonathan Obrist-Farner, a geologist at Missouri University of Science and Technology. “What we see is lakes that are actually the closest to the epicenter but just away from the rupture path have very thin deposits.”

Jeremy Maurer, a geophysicist also at Missouri University, suggested that the unusual pattern had in this case recorded the directivity of the 1976 shaking.

It’s not unusual for scientists to find evidence of past earthquakes in lake sediment cores, Maurer added, noting examples from New Zealand to Turkey that offer a glimpse at how far away a particular earthquake could have an impact.

“What hasn’t been done as much is looking at where these lakes are located in relationship to the fault,” said Maurer. “Are they off-axis or on-axis? Does the direction of the rupture have an effect on sediment deposits?”

When the U.S. Geological Survey collected field data after the 1976 earthquake, “they found, for example, adobe houses that were 10 kilometers south of the main rupture path that were still standing, yet those that were actually on the fault trace and towards the propagation direction all collapsed,” said Maurer. “I think there’s a lot of evidence that points to the directivity of the rupture and now we’re just looking at it sedimentologically from the lakes.”

The researchers began recovering and analyzing cores from the lakes in 2022. “We thought it would be a very interesting opportunity to not just look at the 1976 earthquake, but actually learn a little bit more about the paleoseismic history of the plate boundary, which we know very little of,” said Obrist-Farner, who is originally from Guatemala.

Although there was a brief rush of seismologists to the region after the 1976 earthquake, the impacts of a 36-year civil war and sparse instrumentation have left the plate boundary poorly monitored. Paleoseismic data like the lake records are important for building a more complete picture of the country’s seismic risk.

Last year Obrist-Farner’s team retrieved their largest cores yet from the lakes, with lengths of sediment that may represent up to four thousand years of lake history. Their initial analysis shows evidence of the 1816 earthquake of at least magnitude 7.5 that is known mostly from historical documents.

Using data compiled from single earthquakes across the world, Christie Rowe of the Nevada Seismological Laboratory at the University of Nevada, Reno and Alex Hatem of the U.S. Geological Survey sought a more comprehensive answer, one that considers both surface and deep traces of seismic rupture and creep.

By compiling observations of recent earthquakes, Rowe and Hatem conclude that from Turkey to California, it’s not just a single strand of a fault but quite often a branching network of fault strands involved in an earthquake, making the fault zone hundreds of meters wide.

“So that suggests that significant parts of the broad array of fractures that develops over many earthquakes can be activated in a single earthquake,” said Rowe, who noted that this width sometimes roughly corresponds to the width of Alquist-Priolo zones established for safe building in California.

“We want to know how this might change things like the shaking patterns that you would expect, or how much radiated energy you get from an earthquake,” Rowe explained. “Because it’s not the same if you have slip distributed on many strands as when it is all on one strand of the fault.”

At the same time, the researchers found that the width of creep zones at these earthquakes are much narrower, both near the surface and 10-25 kilometers deep in the earth. The creep zones, between 2 and 10 meters wide, “may be the most localized behavior a fault does,” Rowe said.

The study emphasizes the importance of thinking of faults in a more three-dimensional manner, said Rowe.

“As a geologist, it’s always kind of been a cognitive disconnect for me when I talk to earthquake modelers who have these two-dimensional features that they model earthquakes on,” she said. “Because the sheer resistance, the strength or the friction, comes from a volume of rock that’s deforming during an earthquake or in between earthquakes. So the size of that volume controls the strength of the fault in some really tangible ways.”

The researchers used a variety of data in their study, including rupture maps, creeping zone width from surveys of slowly shifting monuments along faults and satellite observations, the locations of earthquake aftershocks, low velocity damage zone widths, and the zones delineated by certain types of rock such as pseudotachylyte, ultramylonite and mylonite that are a signature of creep and deformation.

The findings also have implications for how scientists study past earthquakes to calculate earthquake recurrence intervals on faults, Rowe noted.

Slip rates and recurrence intervals can be constrained using localized measurements, but it can be difficult to disentangle the slip that occurred during an earthquake and aseismic slip that occurred after the event. The 2014 Napa, California earthquake is a good example of this phenomenon, said Rowe, noting that almost half of the slip measured after that event occurred slowly after the earthquake.

But if the Napa earthquake occurred thousands of years ago and researchers came across its traces in the rock record, “you would just see a bigger earthquake. You might lump all of that slip as a single event,” Rowe said.

Creep isn’t always accounted for in calculating recurrence intervals, “so finding out that creep zones are quite narrow means that we should be aware that we could be convolving creep with seismic slip when we look at those paleoseismic records,” she added.

And that’s why planetary scientists are also interested in finding deltas on Saturn’s moon Titan. Titan is the only planetary body in the solar system besides Earth that has liquid currently flowing across its surface, so its deltas could be a scientific treasure trove.

One problem: Titan appears to be largely devoid of deltas, a new study finds, despite its large rivers of liquid methane and ethane.

“It’s kind of disappointing as a geomorphologist because deltas should preserve so much of Titan’s history,” said Sam Birch, an assistant professor in Brown University’s Department of Earth, Environmental and Planetary Sciences who led the work.

But the absence of deltas raises a host of new questions.

“We take it for granted that if you have rivers and sediments, you get deltas,” Birch said. “But Titan is weird. It’s a playground for studying processes we thought we understood.”

Titan is the largest of Saturn’s 274 confirmed moons. Its thick nitrogen and methane atmosphere gives rise to a host of Earth-like climate and weather features. Titan has clouds, wind and rain as well as rivers, lakes and seas. But instead of water, Titan’s fluid bodies contain methane and ethane, which are liquid at Titan’s chilly surface temperatures.

Scientists learned of Titan’s liquid bodies when the Cassini spacecraft flew by in 2006. Peering through Titan’s thick atmosphere with Cassini’s synthetic aperture radar (SAR), the spacecraft revealed spidering channels and large flat areas consistent with large bodies of liquid.

Largely missing from Cassini’s SAR images, however, were deltas — even at the mouths of large rivers. It wasn’t clear, however, whether the deltas were truly absent, or whether they just didn’t show up in Cassini’s SAR data. That’s the question Birch and his colleagues tried to answer with this new study, published in the Journal of Geophysical Research: Planets.

The problem with Cassini’s SAR data is that shallow liquid methane is largely transparent in any images. So while the SAR images could see the broad seas and river channels, it’s harder to confidently make out coastal features because it’s difficult to see where the coast ends and where the sea floor begins.

For the study, Birch developed a numerical model to simulate what Cassini’s SAR would see if it looked at a landscape scientists understand well: Earth. In the model, the water in Earth’s rivers and oceans was replaced by Titan’s methane liquid, which has different radar absorption properties compared to water.

“We basically made synthetic SAR images of Earth that assume properties of Titan’s liquid instead of Earth’s,” Birch said. “Once we see SAR images of a landscape we know very well, we can go back to Titan and understand a bit better what we’re looking at.”

The research found that the synthetic SAR images of Earth clearly resolved large deltas and many other large coastal landscapes.

“If there are deltas the size of the one at the mouth of the Mississippi River, we should be able to see it,” Birch said. “If there are large barrier islands and similar coastal landscapes like those we see all along the U.S. Gulf Coast, we should be able to see those.”

But when Birch and his colleagues combed over the Titan images in light of their new analysis, they came up mostly empty. Aside from two probable deltas near Titan’s south pole, the rest of the moon’s rivers were entirely delta-free. The researchers found that only about 1.3% of Titan’s large rivers that terminate at coastlines have deltas. On Earth, in contrast, nearly every river of similar size has a delta.

It’s not entirely clear why Titan generally lacks deltas, Birch says. The fluid properties of Titan’s rivers should make them perfectly capable of carrying and depositing sediment. It could be, the researchers say, that sea levels on Titan rise and fall so rapidly that deltas are smeared across the landscape more quickly than they can be built up in a single spot. Winds and tidal currents along Titan’s coasts may also play an equally large role in preventing delta formation.

And missing deltas aren’t the only mystery raised by the new research. The new analysis of Cassini SAR data of Titan’s coasts revealed pits of unknown origin deep within lakes and seas. The study also found deep channels on the floors of the seas that seem to have been carved by river flows, but it’s not clear how they got there.

All of these surprises will require more research to fully understand, Birch says.

“This is really not what we expected,” Birch said. “But Titan does this to us a lot. I think that’s what makes it such an engaging place to study.”

Constructed using 22 small pressure sensors and fueled by small solar panels on the tops of shoes, the system offers real-time health tracking based on how a person walks, a biomechanical process that is as unique as a human fingerprint.

This complex personal health data can then be transmitted via Bluetooth to a smartphone for quick and detailed analysis, said Jinghua Li, co-author of the study and an assistant professor of materials science and engineering at The Ohio State University.

“Our bodies carry lots of useful information that we’re not even aware of,” said Li. “These statuses also change over time, so it’s our goal to use electronics to extract and decode those signals to encourage better self health care checks.”

It’s estimated that at least 7% of Americans suffer from ambulatory difficulties, activities that include walking, running or climbing stairs. While efforts to manufacture a wearable insole-based pressure system have risen in popularity in recent years, many previous prototypes were met with low energy limitations and unstable performances.

To overcome the challenges of their precursors, Li and Qi Wang, the lead author of the study and a current PhD student in materials science and engineering at Ohio State, sought to ensure that their wearable is durable, has a high degree of precision when collecting and analyzing data, and can provide consistent and reliable power, said Li.

“Our device is innovative in terms of high resolution, spatial sensing, self-powering capability, and its ability to combine with machine learning algorithms,” she said. “So we feel like this research can go further based on the pioneering successes of this field.”

The study was recently published in the journal Science Advances.

This team’s system is also made unique through its use of AI. Using an advanced machine learning model, the wearable can recognize eight different motion states, including static ones like sitting and standing to more dynamic movements such as running and squatting.

Additionally, since the materials the insoles are made of are flexible and safe, the device, much like a smartwatch, is low-risk and safe for continuous use. For instance, after the solar cells convert sunlight to energy, that power is stored in tiny lithium batteries that don’t harm the user or affect daily activities.

Because of the distribution of sensors from toe to heel, the researchers could see how the pressure on parts of the foot is different in activities such as walking versus running.

During walking, pressure is applied sequentially from the heel to the toes, whereas during running, almost all sensors are subjected to pressure simultaneously. In addition, during walking, the pressure application time accounts for about half of the total time, while during running, it accounts for only about a quarter.

In health care, the smart insoles could support gait analysis to detect early abnormalities associated with foot pressure-related conditions (such as diabetic foot ulcers), musculoskeletal disorders (such as plantar fasciitis) and neurological conditions (such as Parkinson’s disease).

The new system also used machine learning to learn and classify different types of motion. That offers opportunities for personalized health management, including real-time posture correction, injury prevention and rehabilitation monitoring. Customized fitness training may also be a future use, the researchers said.

According to the study, these smart insoles showed no notable deterioration in performance after 180,000 cycles of compression and decompression, showing their long-term durability.

“The interface is flexible and quite thin, so even during repetitive deformation, it can remain functional,” said Li. “The combination of the software and hardware means it isn’t as limited.”

Researchers expect the technology will likely be available commercially within the next three to five years. Next steps to advance the work will be aimed at improving the system’s gesture recognition abilities, which, according to Li, will likely be helped with further testing on more diverse populations.

“We have so many variations among individuals, so demonstrating and training these fantastic capabilities on different populations is something we need to give further attention to,” said Li.

Other co-authors include Hui Guan, Chen Wang, Peiming Lei, Hongwei Sheng, Huasheng Bi, Jinkun Hu, Chenhui Guo, Yichuan Mao, Jiao Yuan, Mingjiao Shao, Zhiwen Jin and Wei Lan from Lanzhou University in China.