New insights on how galaxies are formed

Astronomers can use supercomputers to simulate the formation of galaxies from the Big Bang 13.8 billion years ago to the present day. But there are a number of sources of error. An international research team, led by researchers in Lund, has spent a hundred million computer hours over eight years trying to correct these.

The last decade has seen major advances in computer simulations that can realistically calculate how galaxies form.

These cosmological simulations are crucial to our understanding of where galaxies, stars and planets come from.

However, the predictions from such models are affected by limitations in the resolution of the simulations, as well as assumptions about a number of factors, such as how stars live and die and the evolution of the interstellar medium.

To minimise the sources of error and produce more accurate simulations, 160 researchers from 60 higher education institutions -- led by Santi Roca-Fàbrega at Lund University, Ji-hoon Kim at Seoul National University and Joel R. Primack at the University of California -- have collaborated and now present the results of the largest comparison of simulations done ever.

"To make progress towards a theory of galaxy formation, it is crucial to compare results and codes from different simulations. We have now done this by bringing together competing code groups behind the world's best galaxy simulators in a kind of supercomparison," says Santi Roca-Fàbrega, a researcher in astrophysics.

Three papers from this collaboration, known as the CosmoRun simulations, have now been published in The Astrophysical Journal. In these, the researchers have analysed the formation of a galaxy with the same mass as the Milky Way.

The simulation is based on the same astrophysical assumptions about the ultraviolet background radiation produced by the first stars in the Universe, the gas cooling and heating, and the process of star formation.

The new results allow the researchers to conclude that disc galaxies like the Milky Way formed very early in the history of the Universe, in line with observations from the James Webb Telescope.

They have also found a way to make the number of satellite galaxies -- galaxies orbiting larger galaxies -- consistent with observations finally solving a problem well known in the community and known as "the missing satellites problem."

In addition, the team has revealed how the gas surrounding galaxies is the key to realistic simulations, rather than the number and distribution of stars, which had previously been the standard.

"The work has been going on for the past eight years and has entailed running hundreds of simulations and using a hundred million hours of supercomputing facilities," says Santi Roca-Fàbrega.

Now the journey continues to further refine the simulations of galaxy formation.

With each technological achievement, Santi Roca-Fàbrega and his colleagues hope to add new pieces to the dizzying puzzle of the birth and evolution of the universe and galaxies.

Read more at Science Daily

Surprising methane discovery in Yukon glaciers: 'Much more widespread than we thought'

Global melting is prying the lid off methane stocks, the extent of which we do not know. A young researcher from University of Copenhagen has discovered high concentrations of the powerful greenhouse gas in meltwater from three Canadian mountain glaciers, where it was not thought to exist -- adding new unknowns to the understanding of methane emissions from Earth's glaciated regions

The helicopter's rotor blades spin as its skillful pilot performs aerial acrobatics between the steep Yukon mountain sides where PhD student Sarah Elise Sapper is leading her first field expedition deep into the heart of the mountains of northwestern Canada. From the helicopter windows, her eyes fall on the jagged edge of the Donjek glacier: meltwater swirls out from beneath the ice like a whirlpool.

Soon after landing, it becomes apparent that Sarah has stumbled upon an unusual find on the first attempt. Seconds after starting up her portable methane analyzer it is clear that the air is enriched with methane and the culprit is soon found. Collecting a sample of meltwater, she measures concentrations of methane that far exceed expectations.

"We expected to find low values in the meltwater because it is believed that glacial methane emissions require larger ice masses such as vast ice sheets. But the result was quite the opposite. We measured concentrations up to 250 times higher than those in our atmosphere," explains Sarah Elise Sapper of the University of Copenhagen's Department of Geosciences and Natural Resource Management.

The field party lifted off and continued to two more mountain glaciers, Kluane and Dusty. And after measuring the methane in the meltwater of each of those two glaciers, the preliminary finding turned out to be more than an anomaly. Here too, measurements showed high methane concentrations. Somewhere beneath the ice, there are previously unknown sources of the gas.

Demonstrates possibility of widespread methane emissions

"The finding is surprising and raises several important questions within this area of research," says Associate Professor Jesper Riis Christiansen of the Department of Geosciences and Natural Resource Management.

Christiansen, the research article's co-author, believes that the finding demonstrates the possibility of methane being present beneath many of the world's glaciers, ones that have thus far been written off.

"When we suddenly see that even mountain glaciers, which are small in comparison with an ice sheet, are able to form and emit methane, it expands our basic understanding of carbon cycling in extreme environments on the planet. The formation and release of methane under ice is more comprehensive and much more widespread than we thought," he says.

Until now, the prevailing view has been that methane in meltwater could only be found in oxygen- free environments under large masses of ice like the Greenland Ice Sheet.

The researchers assume that the production of methane is biological and happens when an organic carbon source -- e.g., deposits from prehistoric marine organisms, soils, peat or forests -- is decomposed by microorganisms in the absence of oxygen, such as we know from wetlands. As such, it is surprising that the mountain glaciers emit methane.

"The meltwater from the surface of glaciers is oxygen-rich when it travels to the bottom of the ice. So we found it quite surprising that all this oxygen is used up somewhere along the way, so that oxygen-free environments form underneath these mountain glaciers. And even more surprising that it happens to such a degree, that microbes start producing methane and we can observe these high methane concentrations in the water flowing out at the glacier edges" states Sarah Elise Sapper.

"Sarah's findings change our basic understanding and send us back to the drawing board in relation to some of the key mechanisms at play," adds Jesper Riis Christiansen.

An uncertain role for the climate of the future

According to the researchers, the findings in Canada do not immediately spur an increased concern in relation to their effect on climate change. However that conclusion may be temporary.

"Methane plays a major role in warming our planet. The challenge with methane is that it is a super-potent greenhouse gas and increasing emissions will accelerate climate warming. From a global perspective, we can measure how much is emitted into the atmosphere and, roughly speaking, where the methane comes from, using the isotopes found in the atmospheric methane. And for now, the contribution of methane from ice-covered regions on our planet, including ice sheets and glaciers, isn't increasing," explains Jesper Riis Christiansen.

However, he emphasizes that the measurements cannot distinguish between methane from glaciated regions and methane from wetlands. Therefore, the numbers could be deceiving. And, the effect of melting remains unknown.

Jesper Riis Christiansen believes that the findings demand vigilance.

"The three sites Sarah measured were randomly selected due to the availability of a research station and helicopter, yet methane was found in all three. In itself, that is a good reason to better understand the area. There's too much that we don't know, and the melting glaciers expose unknown environments that have remained hidden for thousands of years. In reality, no one knows how emissions will behave," says Jesper Riis Christiansen.

He hopes that a better understanding of methane behaviour beneath glaciers will also help researchers better understand the mechanisms at play when wetlands release methane, and thereby contribute to the development of solutions to remove methane from the atmosphere through oxidation -- e.g., through the use of certain soil types.

A subglacial black box

The actual sources and locations of subglacial methane production actually remain somewhat of a mystery, hidden beneath ice masses of all sizes. Indeed, this methane can only be measured as the meltwater emerges from beneath the ice. And because it originates from large areas below the ice masses, this makes it difficult to access exactly where the production happens.

It is known to not originate from the ice itself, as concentrations both in the ice and meltwater atop it are lower than what is measured at the glacier edge. As such, the researchers believe that the methane must derive from a source beneath the ice. And the best theory, as mentioned, is that it is formed by microbes in oxygen-free pockets and then carried out with meltwater.

But this indirect knowledge of the source leaves a great deal of uncertainty about how much methane is hidden beneath the ice.

"It's a big black box under the ice -- and you could say that the meltwater is prying the lid off it. We do not know whether methane emissions from glacial areas will increase in the future with increased melting, or whether the 'lid' has already been opened to such a degree that the methane beneath the ice is actually being washed out with the meltwater," says Sarah Elise Sapper.

Methane and CO2 are different greenhouse gases

The half-life of methane in the atmosphere is 12 years.

CO2 has a much longer half-life, at roughly 1000 years.

On the other hand, methane is about 25 times more powerful as a greenhouse gas on a 100-year basis and a far more serious threat to global climate in the shorter term.

Due to greenhouse gas-driven climate change, researchers around the world are working to develop ways to capture or store CO2.

Similarly, solutions are being devised to limit the emission of -- or increase the oxidation of -- methane. Doing so requires more knowledge about how methane is formed.

Facts: Carbon circulation of methane and CO2

Biological traces from animal and plant material in the subsoil consist of carbon.

Within these environments, microorganisms have developed an ability to convert carbon into energy in a process where methane is created as a byproduct in the absence of oxygen (e.g. in beneath ice sheets or in wetlands).

However, if the methane is released into an oxygen-rich environment, it can effectively be oxidized and converted into CO2 by microbes. Wetlands play an important role in this process.

Once, in the atmosphere, methane reacts with other chemicals (hydroxyl radicals) which keep the concentrations down.

Read more at Science Daily

Slimming down a colossal fossil whale

A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists at UC Davis and the Smithsonian Institution. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded. The work is published Feb. 29 in PeerJ.

A fossil skeleton of Perucetus was discovered in Peru and described in a paper in Nature last year.

The animal lived about 39 million years ago and belonged to an extinct group of early whales called the basilosaurids.

Perucetus' bones are unusually dense. Mammal bones usually have a solid exterior and are spongy or hollow in the center.

Some animals have more of the center filled in with solid bone, making them dense and heavy.

In aquatic animals, heavy bones can offset buoyancy from body fat and blubber, allowing the animal to maintain neutral buoyancy in water or -- in the case of the hippopotamus -- to walk on river beds.

The fossil whale bones have both extensive in-filling and extra growth of bone on the outside as well, a condition called pachyostosis also seen in some modern aquatic mammals, such as manatees.

Based on a series of assumptions, the original authors (Giovanni Bianucci at the University of Pisa, Italy and colleagues) estimated a body mass for Perucetus of 180 metric tons (ranging from 85 to 340 metric tons). This would make Perucetus as heavy as, or heavier than the biggest blue whales known, even though it is considerably shorter at 17 meters long compared to a blue whale at about 30 meters.

How to weigh a whale?

Professor Ryosuke Motani, a paleobiologist at the UC Davis Department of Earth and Planetary Sciences, said that these estimates would make Perucetus impossibly dense.

"It would have been a job for the whale to stay at the surface, or even to leave the sea bottom -- it would have required continuous swimming against the gravity to do anything in the water," Motani said.

Motani and Nick Pyenson at the Smithsonian Institute National Museum of Natural History reexamined the assumptions used to make those estimates.

The first problem is that Bianucci et al used the fossil bones to estimate the weight of the skeleton, then extrapolated to the weight of the entire animal, assuming that the skeletal and non-skeletal mass would scale at the same rate with increasing body size.

But measurements of other animals show this is not the case, Motani and Pyenson argue.

The original estimates also overestimated how much overall body mass increases as a result of pachyostosis.

But evidence from manatees shows that their bodies are relatively light relative to their skeletal mass.

Motani and Pyenson estimate that the 17-meter long Perucetus weighed in at 60 to 70 tons, considerably less than the known weights of blue whales.

A Perucetus that grew to 20 meters could weigh over 110 tons, still well short of the largest blue whales at 270 tons.

"The new weight allows the whale to come to the surface and stay there while breathing and recovering from a dive, like most whales do," Motani said.

Read more at Science Daily

Human stem cells coaxed to mimic the very early central nervous system

The first stem cell culture method that produces a full model of the early stages of the human central nervous system has been developed by a team of engineers and biologists at the University of Michigan, the Weizmann Institute of Science, and the University of Pennsylvania.

"Models like this will open doors for fundamental research to understand early development of the human central nervous system and how it could go wrong in different disorders," said Jianping Fu, U-M professor of mechanical engineering and corresponding author of the study in Nature.

The system is an example of a 3D human organoid -- stem cell cultures that reflect key structural and functional properties of human organ systems but are partial or otherwise imperfect copies.

"We try to understand not only the basic biology of human brain development, but also diseases -- why we have brain-related diseases, their pathology, and how we can come up with effective strategies to treat them," said Guo-Li Ming, who along with Hongjun Song, both Perelman Professors of Neuroscience at UPenn and co-authors of the study, developed protocols for growing and guiding the cells and characterized the structural and cellular characteristics of the model.

For example, organoids developed using patient-derived stem cells may be used for identifying which drugs offer the most successful treatment. Already, human brain and spinal cord organoids are used to study neurological and neuropsychiatric diseases, but they often mimic one part of the central nervous system and are disorganized. The new model, in contrast, recapitulates the development of all three sections of embryonic brain and spinal cord simultaneously, a feat that has not been achieved in previous models.

"The system itself is really groundbreaking," said Orly Reiner, the Berstein-Mason Professorial Chair of Neurochemistry at Weizmann and co-author of the study who developed cellular tools to identify neural cell types in the model. "A model that mimics this structure and organization has not been done before, and it offers numerous possibilities for studying human brain development and especially developmental brain diseases."

While the model is faithful to many aspects of the early development of the brain and spinal cord, the team notes several important differences. For one, neural tube formation -- the very first stage of central nervous system development -- is very different. The model can't be used to simulate disorders that stem from improper closure of the neural tube such as spina bifida.

Instead, the model started with a row of stem cells roughly the size of the neural tube found in a 4-week-old embryo -- about 4 millimeters long and 0.2 millimeters in width. The team stuck the cells to a chip patterned with tiny channels that the team used to introduce materials that enabled the stem cells to grow and guided them toward building a central nervous system.

The team then added a gel that allowed the cells to grow in three dimensions and chemical signals that nudged them to become the precursors of neural cells. In response, the cells formed a tubular structure. Next, the team introduced chemical signals that helped the cells identify where they were within the structure and progress to more specialized cell types. As a result, the system organized itself to mimic the forebrain, midbrain, hindbrain and spinal cord in a way that mirrors embryonic development.

"As an engineer, the challenging part is to learn neural development and stem cell biology," said Xufeng Xue, first author of the study and a postdoctoral fellow in mechanical engineering U-M. "It was a team effort to make this happen, with amazing collaborators at UPenn and Weizmann."

The team grew the cells for 40 days, simulating development of the central nervous system to about 11 weeks post-fertilization. In this time, the team was able to demonstrate the roles of specific genes in spinal cord development and learn how certain cell types in the early human nervous system differentiate into different cells with specialized functions.

"In many cases, animal models simply do not recapitulate either the characteristics or the degree of severity seen in human brain diseases such as microcephaly," Song said. "Even nonhuman primates are not the same. So in the context of disease biology and treatment strategies, a human cell model is almost irreplaceable."

The team plans to apply the model to study different human brain diseases using patient derived stem cells.

Xue hopes to continue using this model to study the interplay among different parts of the brain during development. He is also interested in studying how the brain sends instructions for movement via the spinal cord. This line of inquiry, which could shed new light on disorders like paralysis, would require the neurons to link up into working circuits -- something that was not observed in this study.

Insoo Hyun, a bioethicist at the Museum of Science in Boston who was not part of the study, notes that experiments like these are closely scrutinized before they are allowed to move forward.

"Research groups must be clear about the scientific question they are trying to answer -- and that the degree of development they allow in the model is the minimum to answer the question," he said.

The model does not include peripheral nerves or functioning neural circuitry -- features that are critical for humans' ability to experience our environment and process that experience.

Read more at Science Daily

Biomolecules from formaldehyde on ancient Mars

Organic materials discovered on Mars may have originated from atmospheric formaldehyde, according to new research, marking a step forward in our understanding of the possibility of past life on the Red Planet.

Scientists from Tohoku University have investigated whether the early atmospheric conditions on Mars had the potential to foster the formation of biomolecules -- organic compounds essential for biological processes.

Their findings, published in Scientific Reports, offer intriguing insights into the plausibility of Mars harboring life in its distant past.

Today, Mars presents a harsh environment characterized by dryness and extreme cold, but geological evidence hints at a more hospitable past.

About 3.8-3.6 billion years ago, the planet probably had a temperate climate, sustained by the warming properties of gases like hydrogen.

In such an environment, Mars may have had liquid water, a key ingredient for life as we know it.

The researchers investigated whether formaldehyde could have formed in the early Martian environment.

Formaldehyde is a simple organic compound that plays a crucial role as a precursor for the formation of vital biomolecules through purely chemical or physical processes.

These biomolecules, like amino acids and sugars, serve as the fundamental building blocks for proteins and RNA, essential components of life.

Using an advanced computer model, the team simulated the potential atmospheric composition of early Mars to explore the potential for formaldehyde production.

The model was built with the assumption that the atmosphere was rich in carbon dioxide, hydrogen, and carbon monoxide.

Their simulations suggest that the ancient Martian atmosphere could have provided a continuous supply of formaldehyde which would have potentially led to the creation of various organic compounds.

This raises the intriguing possibility that the organic materials detected on the Martian surface could have originated from atmospheric sources, particularly during the planet's two earliest geological periods.

"Our research provides crucial insights into the chemical processes that may have occurred on ancient Mars, offering valuable clues to the possibility of past life on the planet," says Shungo Koyama, lead author of the study.

By revealing that there were conditions favorable for the formation of bio molecules, the research broadens our understanding of the planet's ancient capacity to sustain life.

Read more at Science Daily

80 mph speed record for glacier fracture helps reveal the physics of ice sheet collapse

There's enough water frozen in Greenland and Antarctic glaciers that if they melted, global seas would rise by many feet. What will happen to these glaciers over the coming decades is the biggest unknown in the future of rising seas, partly because glacier fracture physics is not yet fully understood.

A critical question is how warmer oceans might cause glaciers to break apart more quickly. University of Washington researchers have demonstrated the fastest-known large-scale breakage along an Antarctic ice shelf. The study, recently published in AGU Advances, shows that a 6.5-mile (10.5 kilometer) crack formed in 2012 on Pine Island Glacier -- a retreating ice shelf that holds back the larger West Antarctic ice sheet -- in about 5 and a half minutes. That means the rift opened at about 115 feet (35 meters) per second, or about 80 miles per hour.

"This is to our knowledge the fastest rift-opening event that's ever been observed," said lead author Stephanie Olinger, who did the work as part of her doctoral research at the UW and Harvard University, and is now a postdoctoral researcher at Stanford University. "This shows that under certain circumstances, an ice shelf can shatter. It tells us we need to look out for this type of behavior in the future, and it informs how we might go about describing these fractures in large-scale ice sheet models."

A rift is a crack that passes all the way through the roughly 1,000 feet (300 meters) of floating ice for a typical Antarctic ice shelf. These cracks are the precursor to ice shelf calving, in which large chunks of ice break off a glacier and fall into the sea. Such events happen often at Pine Island Glacier -- the iceberg observed in the study has long since separated from the continent.

"Ice shelves exert a really important stabilizing influence on the rest of the Antarctic ice sheet. If an ice shelf breaks up, the glacier ice behind really speeds up," Olinger said. "This rifting process is essentially how Antarctic ice shelves calve large icebergs."

In other parts of Antarctica, rifts often develop over months or years. But it can happen more quickly in a fast-evolving landscape like Pine Island Glacier, where researchers believe the West Antarctic Ice Sheet has already passed a tipping point on its collapse into the ocean.

Satellite images provide ongoing observations. But orbiting satellites pass by each point on Earth only every three days. What happens during those three days is harder to pin down, especially in the dangerous landscape of a fragile Antarctic ice shelf.

For the new study, the researchers combined tools to understand the rift's formation. They used seismic data recorded by instruments placed on the ice shelf by other researchers in 2012 with radar observations from satellites.

Glacier ice acts like a solid on short timescales, but it's more like a viscous liquid on long timescales.

"Is rift formation more like glass breaking or like Silly Putty being pulled apart? That was the question," Olinger said. "Our calculations for this event show that it's a lot more like glass breaking."

If the ice were a simple brittle material, it should have shattered even faster, Olinger said. Further investigation pointed to the role of seawater. Seawater in the rifts holds the space open against the inward forces of the glacier. And since seawater has viscosity, surface tension and mass, it can't just instantly fill the void. Instead, the pace at which seawater fills the opening crack helps slow the rift's spread.

"Before we can improve the performance of large-scale ice sheet models and projections of future sea-level rise, we have to have a good, physics-based understanding of the many different processes that influence ice shelf stability," Olinger said.

Read more at Science Daily

Predatory fish use rapid color changes to coordinate attacks

Striped marlin are some of the fastest animals on the planet and one of the ocean's top predators. When hunting in groups, individual marlin will take turns attacking schools of prey fish one at a time. Now a new study reported in the journal Current Biology on February 5 helps to explain how they might coordinate this turn-taking style of attack on their prey to avoid injuring each other. The key, according to the new work, is rapid color changes.

"We documented for the first time rapid color change in a group-hunting predator, the striped marlin, as groups of marlin hunted schools of sardines," says Alicia Burns of Humboldt University in Berlin, Germany.

"We found that the attacking marlin 'lit up' and became much brighter than its group-mates as it made its attack before rapidly returning to its 'non-bright' coloration after its attack ended."

Burns and her colleagues, including Jens Krause, explained that the use of drones in their research has given them a new perspective of how marlins move and hunt.

As they examined the video footage they'd captured via drone, they noticed something unexpected: the stripes on individual marlins got obviously brighter as a fish moved in for an attack.

As they swam away, those stripes dimmed again. Were the fish changing colors to communicate with one another?

To explore this question in the new study, the researchers analyzed 12 high-resolution video clips, each containing two separate attacks on a school of sardines by two different marlin.

They also quantified the contrast of the stripes on the two attacking marlins compared to a randomly chosen marlin that wasn't attacking.

Their analysis confirms that the predatory fish rapidly change color, suggesting that the color change might serve as a reliable signal of an individual's motivation to go in for an attack.

"Color change in predators is rare, but especially so in group-hunting predators," Burns said.

"Although it is known that marlin can change color, this is the first time it's been linked to hunting or any social behavior."

The discovery suggests that marlins have more complicated communication channels than had been suspected.

The researchers propose that the color changes might even serve a dual purpose of confusing their prey.

They now hope to explore this idea, alongside other questions.

For example, they want to find out whether marlins use their color-changing abilities in other contexts.

They're curious to know whether they still change color when hunting solo and how the changes affect their prey.

They are also looking into similar color changes in other predatory species of fish.

Read more at Science Daily

Blindness from some inherited eye diseases may be caused by gut bacteria

Sight loss in certain inherited eye diseases may be caused by gut bacteria, and is potentially treatable by antimicrobials, finds a new study in mice co-led by a UCL and Moorfields researcher.

The international study observed that in eyes with sight loss caused by a particular genetic mutation, known to cause eye diseases that lead to blindness, gut bacteria were found within the damaged areas of the eye.

The authors of the new paper, published in Cell and jointly led by researchers in China, say their findings suggest that the genetic mutation may relax the body's defences, thus allowing harmful bacteria to reach the eye and cause blindness.

The gut contains trillions of bacteria, many of which are key to healthy digestion. However, they can also be potentially harmful.

The researchers were investigating the impact of the Crumbs homolog 1 (CBR1) gene, which is known to be expressed in the retina (the thin layer of cells at the back of the eye) and is crucial to building the blood-retina barrier to regulate what flows in and out of the eye.

The CRB1 gene is associated with inherited eye disease, most commonly forms of Leber congenital amaurosis (LCA) and retinitis pigmentosa (RP); the gene is the cause of 10% of LCA cases and 7% of RP cases worldwide.

Using mouse models, the research team discovered the CRB1 gene is key to controlling the integrity of the lower gastrointestinal tract, the first ever such observation. There, it combats pathogens and harmful bacteria by regulating what passes between the contents of the gut and the rest of the body.

The team found that when the gene has a particular mutation, dampening its expression (reducing its effect), these barriers in both the retina and the gut can be breached, enabling bacteria in the gut to move through the body and into the eye, leading to lesions in the retina that cause sight loss.

Crucially, treating these bacteria with antimicrobials, such as antibiotics, was able to prevent sight loss in the mice even though it did not rebuild the affected cell barriers in the eye.

Inherited eye diseases are the UK's leading cause of blindness in working-age people. Onset of disease may vary from very early childhood to adulthood, but deterioration is irreversible and has lifelong implications. To date, the development of treatments has largely focused on gene therapies.

The findings of this study suggest that simply using antimicrobials might help prevent deterioration in CRB1-associated inherited eye diseases. Future work will investigate whether this applies in humans.

Co-lead author Professor Richard Lee (UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust) said: "We found an unexpected link between the gut and the eye, which might be the cause of blindness in some patients.

"Our findings could have huge implications for transforming treatment for CRB1-associated eye diseases. We hope to continue this research in clinical studies to confirm if this mechanism is indeed the cause of blindness in people, and whether treatments targeting bacteria could prevent blindness.

"Additionally, as we have revealed an entirely novel mechanism linking retinal degeneration to the gut, our findings may have implications for a broader spectrum of eye conditions, which we hope to continue to explore with further studies."

Read more at Science Daily

Three years later, search for life on Mars continues

In the three years since NASA's Perseverance rover touched down on Mars, the NASA science team has made the daily task of investigating the red planet seem almost mundane.

The rover and its helicopter sidekick Ingenuity have captured stunning images of Mars and collected 23 unique rock core samples along 17 miles of an ancient river delta.

One science team member, University of Cincinnati Associate Professor Andy Czaja, said he sometimes has to remind himself that the project is anything but ordinary.

"This is so cool. I'm exploring another planet," he said.

Czaja teaches in the Department of Geosciences in UC's College of Arts and Sciences. He is a paleobiologist and astrobiologist helping NASA look for evidence of ancient life on Mars using a rover outfitted with custom geoscience and imaging tools with three of his UC graduate students, Andrea Corpolongo, Brianna Orrill and Sam Hall.

Three years into the mission, the rover has performed like a champ, he said.

"Perseverance has excelled. It's been fantastic. It has such capable instrumentation for doing the geology work. It's able to explore distant objects with its zoom lens cameras and can focus on tiny objects at incredible resolution," Czaja said.

Along the way, the mission has recorded a number of firsts: first powered flight, first recorded sounds of Mars, the longest autonomous drive (nearly a half-mile) and new discoveries about the planet's geology, atmosphere and climate.

Czaja was part of the NASA team that decided where on Mars to land the rover. And he remained on the science team that would pore over its daily data and discoveries to decide what the rover should do next.

Among the new discoveries was finding primary igneous rocks in Jezero Crater. These rocks are the hardened result of liquid magma. They offer scientists promising clues about refining the known age of the planet.

Scientists suspect Mars once had long-lived rivers, lakes and streams. Today, water on Mars is found in ice at the poles and trapped below the Martian surface.

Czaja and his student Corpolongo were co-lead authors of a paper published in the Journal of Geophysical Research, Planets that revealed that Mars also may have had hydrothermal systems based on the hydrated magnesium sulfate the rover identified in the volcanic rocks.

"When those rocks cool off and fracture, they become a habitable environment for life," Czaja said.

Corpolongo also led a similar research paper in the same journal co-authored by Czaja detailing the results of the rover's analysis of samples using the SHERLOC deep ultraviolet Raman and fluorescence instrument. Both papers featured contributions from dozens of their fellow NASA researchers on the project.

Samples collected by the rover may finally answer the question about whether we are alone in the universe.

"We have not found any definitive evidence of life in these deposits yet. But if there were fossil microorganisms trapped in the rocks, they would be too small to see with the rover," Czaja said.

Czaja is hopeful funding will be approved for the anticipated Mars Sample Return mission to retrieve the hermetically sealed titanium tubes scientists have spent three years filling with interesting rock cores.

"These hydrated minerals trap water within themselves and record the history of how and when they formed," the study said. "Returning samples of these minerals to Earth would allow researchers to explore the history of Mars' water and climate and possibly evidence of ancient life with the most sensitive instruments possible."

But that was just the beginning. Perseverance began its deliberate exploration from the floor of the crater to the front of the delta, formed by an ancient river or drainage channel where it encountered sedimentary rocks that often contain trapped minerals and another avenue for evidence of ancient life.

And last year the rover made it to the crater's margin in what used to be an enormous lake where it is exploring deposits of magnesium carbonate, which can form geologically or biologically from bacteria.

Czaja said the decision to send Perseverance to Jezero Crater appears to be paying off.

"Absolutely. There were other places we could have gone that might have been just as good," he said. "You won't know until you explore them all. But Jezero was picked for good reason and it has been completely justified."

The helicopter Ingenuity's flying days appear to be over after it sustained rotor damage in January after landing on its 72nd flight. But Perseverance is still going strong. It still has 15 sample tubes at its disposal to capture additional interesting geologic specimens.

Next the rover will make its way out of Jezero Crater to explore the wider area. Czaja said they are likely to find rocks dating back 4 billion years or more. And Mars could harbor stromatolites or rocks that contain evidence of ancient layered mats of bacteria visible to the naked eye. On Earth, these rocks are sometimes found in extreme environments such as geyser basins.

Read more at Science Daily

New study is first step in predicting carbon emissions in agriculture

For the first time, researchers at the University of Minnesota Twin Cities (UMN) and the University of Illinois Urbana-Champaign (UIUC) have demonstrated that it is possible to provide accurate, high-resolution predictions of carbon cycles in agroecosystems, which could help mitigate the impacts of climate change.

The study by scholars from the UMN-led National Artificial Intelligence Institute for Climate-Land Interactions, Mitigation, Adaptation, Tradeoffs and Economy (AI-CLIMATE) and UIUC-led Agroecosystem Sustainability Center was recently published in Nature Communications, a peer-reviewed, open access, scientific journal.

The study's findings are a critical first step in developing a credible Measurement, Monitoring, Reporting, and Verification (MMRV) of agricultural emissions that can be used to incentivize the implementation of climate smart practices while boosting rural economies. This follows the national strategy, set by the White House, highlighting the need to quantify greenhouse gas emission across sectors with a goal of net-zero emissions by no later than 2050.

Accurate, scalable, and cost-effective monitoring and reporting of greenhouse gas emissions are needed to verify what are called "carbon credits" or permits that offset greenhouse gas emissions. Farmers can be reimbursed for practices that reduce greenhouse gas emissions. Agriculture accounts for about 25 percent of greenhouse gas emissions, but large corporations can be hesitant about purchasing these credits without knowing how much carbon is being stored.

Right now, to accurately gather carbon data, a farmer would need to hire someone to come to their farm, take what is called a soil core (vertical profile of the soil), and send that back to the lab for analysis.

"To gather the amount of data needed at each individual farm, it could cost the farmers time and money that they may not be willing to give," said Licheng Liu, the lead author and a research scientist in the University of Minnesota Department of Bioproducts and Biosystems Engineering.

The emerging field of Knowledge-Guided Machine Learning (KGML), pioneered by researchers at the University of Minnesota, combines the strength of artificial intelligence (AI) and process-based models from physical sciences. With observations in the United States Corn Belt, the KGML-ag framework significantly surpasses both process-based and pure machine learning models in accuracy, especially with limited data. Remarkably, KGML-ag operates over 10,000 times faster than traditional process-based models, delivering high-resolution and high-frequency predictions cost-effectively.

"These knowledge-guided machine learning (KGML) techniques are fundamentally more powerful than standard machine learning approaches and traditional models used by the scientific community to address environmental problems," said Vipin Kumar, a University of Minnesota Regents Professor and William Norris Endowed Chair in the Department of Computer Science and Engineering and a researcher in the AI-CLIMATE Institute, whose group has pioneered the development of the KGML framework.

Instead of taking soil cores at every farm, with KGML-ag, researchers can use the power of satellite remote sensing, computational models, and AI to provide an estimate of carbon in each individual field. This allows for compensation to individual farmers that are fair and accurate. The researchers say this is key to fostering trust in carbon markets and supporting the adoption of sustainable practices.

"KGML-ag combines the most advanced understanding of mechanisms in agriculture with the state-of-the-art AI techniques and thus offers a new powerful lens to monitor and manage our agricultural ecosystems," said Zhenong Jin, the corresponding author for this study and assistant professor in the University of Minnesota Department of Bioproducts and Biosystems Engineering, who co-leads the KGML special interest group in the AI-CLIMATE.

Now, AI-CLIMATE researchers are investigating the potential of the KGML framework for forestry, leveraging its capabilities to address the pressing challenges in sustainable forestry management and the capturing and storing of carbon. The team is also exploring a KGML-based data assimilation approach to make use of the rapidly growing different kinds of satellite data flexibly.

"The KGML is one of the key research topics of the AI-CLIMATE," said Shashi Shekhar, a University of Minnesota ADC Chair and Distinguished McKnight University Professor in the Department of Computer Science and Engineering and the lead researcher of the AI-CLIMATE Institute. "These initial results demonstrate the immense potential of AI for developing more accurate and cheaper methods for estimating emissions from agriculture. This may lubricate carbon markets and incentivize adoption of climate-smart practices."

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