On Earth-like planets, the characteristic reflectance spectrum of terrestrial vegetation, known as “vegetation red edge,” is considered as a key biosignature. However, ocean planets, with most of their surfaces covered by water, are unlikely to support terrestrial vegetation. To broaden the scope of life detection on ocean planets, this study examined the characteristics of reflectance spectra from floating plants and tested their detectability.

The study investigated the reflectance spectra of floating plants across different scales, from individual leaves in laboratory settings to large-scale observation via satellite remote sensing of lake vegetation.

Although floating leaves exhibit considerable morphological variation among species, their general trend reveals a pronounced red edge, often comparable to or even exceeding that of terrestrial plants. This enhancement is attributed to air gaps in sponge tissue that provide buoyancy and specialized epidermal structures that offer water repellency. While floating leaves show slightly reduced reflectance when wet, they still display a more distinct red edge than submerged water plants.

However, on a larger scale, the red edge signature of floating vegetation weakens due to lower vegetation density and reduced leaf overlap on the water surface. Landscape-scale analyses using satellite remote sensing (Sentinel-2; ESA) with the Normalized Difference Vegetation Index (NDVI) flourishes in summer and disappears in winter, causing the NDVI to be relatively low when averaged over the year. Nevertheless, the fluctuation between minimum and maximum NDVI values is more pronounced for floating vegetation compared to forests. To further investigate this pattern, a large-scale survey of 148 lakes and marshes across Japan was conducted. The study revealed a characteristic seasonal NDVI variation, shifting from negative values in winter to positive values in summer. Importantly, while water suppresses the reflectance of floating vegetation, its own reflectance is even lower and remains stable. It enhances the detectability of seasonal NDVI fluctuations, which remain robust against atmospheric and cloud interference, suggesting that this method could be promising for detecting life on habitable exoplanets in the future.

If photosynthetic organisms, such as floating plants, exist universally on habitable exoplanets, then the scope of life exploration can be expanded to include ocean planets rather than being limited to Earth-like planets. It is important to understand the origin and evolutionary process of life as it coevolves with planetary environments to predict the morphology of organisms that may adapt to diverse planetary conditions. This study provides a foundation for future research on biosignatures, paving the way for the next generation of life-detection missions.

These populations in south-western Sydney are among the very few in New South Wales (NSW) still free of chlamydia, a highly contagious disease causing infertility that has severely diminished populations elsewhere in the continent’s eastern states.

However, analysis of these koalas led by Dr Elspeth McLennan and Professor Carolyn Hogg at the University’s School of Environmental and Life Sciences shows how vulnerable they are to environmental threats and outbreaks of disease. Highly inbred and with low genetic diversity, they are less likely to adapt to the disease should it arrive on their doorstep.

The findings have been published in Conservation Genetics.

Tissue samples from 111 koalas were collected by NSW Government staff from seven sites in the south-western Sydney suburbs of Liverpool, Campbelltown, Heathcote and Wollondilly, and from Wingecarribee in the Southern Highlands.

Genetic analysis showed a high level of interrelatedness, inbreeding and worryingly low genetic diversity across Sydney koalas.

Low genetic diversity means populations cannot always adapt to change, making them highly susceptible to environmental threats and disease outbreaks.

“On average, koalas in the Sydney populations have cousin or half-sibling relationships,” said Dr McLennan.

Living in highly urbanised areas limits opportunities for Sydney’s koalas to move around and breed with populations further afield and increase the diversity needed to build resilience. However, there is a chance that koalas from the neighbouring Wollondilly Shire, where chlamydia is present, may find their way to the Sydney populations. Gene flow analysis showed koalas are moving between Wollondilly and Campbelltown, the southern-most chlamydia-free site.

“It’s a classic Catch-22 situation,” said Dr McLennan. “If the Wollondilly koalas breed with those elsewhere in Sydney they could increase genetic diversity. But they may bring chlamydia with them. If the latter happens, individual koalas are unlikely to have enough genetic variation to adapt to the threat.

“Instead of some individuals being able to naturally clear chlamydia without it progressing to blindness and infertility, it is possible all individuals will contract the infection whereby it progresses to the later stages of the disease.”

Dr McLennan says there is no ready solution to addressing the threats, including anthropogenic threats from climate change and ongoing urbanisation, to koalas in south-west Sydney. Simply improving habitat connectivity to increase genetic diversity may promote chlamydia spread, she said.

“Beyond south-west Sydney, the results show the importance of managing koala populations and their surrounding landscapes. We need to ensure ongoing connectivity between all koala populations to maintain their health and resilience to threats.”

Koalas in Queensland, New South Wales and the Australian Capital Territory were listed as endangered in 2022. Their populations have decreased 24 percent in the last 20 years.

The research highlights an issue faced by conservationists worldwide too.

“Without diversity, endangered species risk succumbing to disease outbreaks and environmental threats.”

Sheng Xu, an Assistant Professor at Tohoku University’s Frontier Research Institute for Interdisciplinary Sciences, emphasized the importance of the alloy’s wide operational temperature range. “This alloy is the first of its kind to maintain superelasticity at such an extreme range of temperatures while remaining lightweight and strong, which opens up a variety of practical applications that were not possible before. The alloy’s properties make it ideal for future space missions, such as creating superelastic tires for lunar rovers to navigate the extreme temperature fluctuations on the Moon’s surface.”

The alloy’s flexibility at extremely low temperatures makes it a promising material for applications in the forthcoming Hydrogen Society and various other industries. Of course, the alloy can be used in everyday applications requiring flexibility, such as medical devices like stents.

Currently, most shape-memory alloys — materials capable of regaining their original shape after force is removed — are limited to specific temperature ranges. The new Ti-Al-based alloy overcomes this limitation, offering wide applicability in fields that require materials with exceptional strength and flexibility, from space exploration to everyday medical tools.

The research team employed advanced techniques such as rational alloy design and precise microstructure control. By using phase diagrams, the researchers were able to select alloy components and their proportions. Additionally, they optimized processing and heat treatment methods to achieve the desired material properties.

The implications of this study extend beyond immediate practical applications. “This discovery not only sets a new standard for superelastic materials but also introduces new principles for material design, which will undoubtedly inspire further breakthroughs in materials science,” Xu added.

Details of the breakthrough were published in the journal Nature on February 26, 2025.

“Migraine disease is debilitating and can lead to kids having to miss school and other activities,” said author Anisa Kelley, MD, of Northwestern University Feinberg School of Medicine in Chicago. “Currently, there is only one FDA-approved migraine preventative medication for this age group. Our results are encouraging, showing zonisamide may be another option for reducing migraine attacks.”

For the study, researchers reviewed health records at one institution. They identified 256 children and teens who had been diagnosed with migraine and prescribed preventative zonisamide. Of these participants, 28% had difficult-to-treat migraine, which was defined as having migraine disease unsuccessfully treated with two or more previous medications. Researchers documented the number of headache days per month for each participant both before and after starting zonisamide.

They then divided participants into three subgroups based on how long they took the medication before a follow-up visit with a physician. The first group followed up in the first month, the second group within two to six months and the third group, after six months.

For all participants, the median number of headache days per month reduced from 18 to six at the first follow-up visit. When comparing between the groups, the subgroup that followed up within two to six months had the largest reduction with a median decrease of six headache days per month. Kelley noted that the data suggested the drug was most effective after at least two months of use.

The data also suggested that the drug was effective for both those with difficult-to-treat migraine disease and those without.

“It’s very exciting that we may have an effective way to treat difficult migraine disease in children and teens, however it’s important to note that our study did have limitations,” said Kelley. “For instance, our study did not compare people taking the medication to people who did not take the medication. Future studies are needed with control groups to confirm our results.”

This study was funded by Stanley Manne Children’s Research Institute at Ann & Robert H. Lurie Children’s Hospital of Chicago.

Published in Science Robotics, the research glimpses a future where nimble microrobots can crawl through tiny spaces, skitter across dangerous ground, and sense their environments without human intervention.

The new Harvard robot was created in the lab of Robert J. Wood, the Harry Lewis and Marlyn McGrath Professor of Engineering and Applied Sciences at SEAS. It is a modification of the Harvard Ambulatory Microrobot (HAMR), a microrobotic platform originally modeled after the dexterous, hard-to-kill cockroach. Now, HAMR is outfitted with a robotic furcula — the forked, tail-like appendage tucked under a springtail’s body that it pushes off the ground to send it Simone Biles-ing into the air.

“Springtails are interesting as inspiration, given their ubiquity, both spatially and temporally across evolutionary scales,” Wood said. “They have this unique mechanism that involves rapid contact with the ground, like a quick punch, to transfer momentum and initiate the jump.”

To go airborne, the robot uses what’s called latch-mediated spring actuation, in which potential energy is stored in an elastic element — the furcula — that can be deployed in milliseconds like a catapult. This physical phenomenon is found time and again in nature, not just in springtails: from the flicking tongue of a chameleon to the prey-killing appendage of a mantis shrimp.

Wood’s team previously created amantis shrimp-inspired punching robot. “It seemed natural to try to explore the use of a similar mechanism, along with insights from springtail jumps, for small jumping robots,” Wood said.

The springtail’s furcula is also elegantly simple, composed of just two or three linked units. “I think that simplicity is what initially charmed me into exploring this type of solution,” said first author and former SEAS research fellow Francisco Ramirez Serrano.

The team used streamlined microfabrication workflows pioneered in the Wood lab to develop the palm-sized, paper clip-light robot that can walk, jump, climb, strike, and even scoop up objects.

The robot demonstrates some of the longest and highest jumps of any existing robot relative to body length; its best performance is 1.4 meters, or 23 times its length. By contrast, a similar robot can jump twice as far but outweighs the Harvard robot by 20 times.

“Existing microrobots that move on flat terrain and jump do not possess nearly the agility that our platform does,” Serrano said.

The team incorporated detailed computer simulations into the design of the robot to help it land optimally every time, precisely controlling for the lengths of its linkages, the amount of energy stored in them, and the orientation of the robot before takeoff.

Packing all manner of athletic abilities into one lightweight robot has the team excited for a future where robots like theirs could traverse places humans can’t or shouldn’t.

“Walking provides a precise and efficient locomotion mode but is limited in terms of obstacle traversal,” Wood said. “Jumping can get over obstacles but is less controlled. The combination of the two modes can be effective for navigating natural and unstructured environments.”

The research was supported by the U.S. Army Research Office under grant No. W911NF1510358.

A research group from Tohoku University has helped shed light on this by improving an existing Mars climate model. The enhanced model accommodates the various properties of Martian regolith, or the loose deposits of solid rock that comprise Martian soil.

Mirai Kobayashi says current models fail to account for the fact that laboratory experiments have demonstrated that the water-holding capacity of the regolith is strongly influenced by its adsorption coefficient.

“Models to date that estimate the distribution of surface and subsurface water on Mars assume that its regolith properties are uniform. This contrasts with observations made by orbiters and landers, which suggest that Martian regolith has globally non-uniform physical properties.”

The model estimated Mars’s subsurface water distribution down to 2 meters from the surface. Like a sponge, highly absorptive regolith in Mars’s mid- and low latitudes retains substantial amounts of absorbed water. Some of this water, the findings showed, remains on the surface of the regolith as stable adsorbed water.

The study also showed that the soil on Mars could keep ice near the surface in the middle and lower areas because water vapor moves more slowly there. This means the soil helps trap water for a long time by slowing down how water vapor spreads, which is important for understanding the change in water on Mars over time.

“Our study stresses the importance of incorporating absorption and inhomogeneity of Martian regolith in forecasting Mars’s surface water,” says Takeshi Kuroda, who led the team alongside Kobayashi, Arihiro Kamada and Naoki Terada. “The model can also be used to study how water on Mars has changed, and how it may have moved deeper underground near the planet’s mantle.”

With several Mars exploration missions underway, including the Japan-led Martian Moons eXploration (MMX) and the international Mars Ice Mapper (MIM) projects, the model is expected to complement further studies that can lead to subsurface water maps of Mars.