Martian rock-metal composite shows potential of 3D printing on Mars

A small amount of simulated crushed Martian rock mixed with a titanium alloy made a stronger, high-performance material in a 3D-printing process that could one day be used on Mars to make tools or rocket parts. The parts were made by Washington State University researchers with as little as 5% up to 100% Martian regolith, a black powdery substance meant to mimic the rocky, inorganic material found on the surface of the red planet. While the parts with 5% Martian regolith were strong, the 100% regolith parts proved brittle and cracked easily. Still, even high-Martian content materials would be useful in making coatings to protect equipment from rust or radiation damage.

A little Martian dust appears to go a long way. A small amount of simulated crushed Martian rock mixed with a titanium alloy made a stronger, high-performance material in a 3D-printing process that could one day be used on Mars to make tools or rocket parts.

The parts were made by Washington State University researchers with as little as 5% up to 100% Martian regolith, a black powdery substance meant to mimic the rocky, inorganic material found on the surface of the red planet.

While the parts with 5% Martian regolith were strong, the 100% regolith parts proved brittle and cracked easily. Still, even high-Martian content materials would be useful in making coatings to protect equipment from rust or radiation damage, said Amit Bandyopadhyay, corresponding author on the study published in the International Journal of Applied Ceramic Technology.

"In space, 3D printing is something that has to happen if we want to think of a manned mission because we really cannot carry everything from here," said Bandyopadhyay, a professor in WSU's School of Mechanical and Materials Engineering. "And if we forgot something, we cannot come back to get it."

Bringing materials into space can be extremely expensive. For instance, the authors noted it costs about $54,000 for the NASA space shuttle to put just one kilogram of payload (about 2.2 pounds) into Earth orbit. Anything that can be made in space, or on planet, would save weight and money -- not to mention if something breaks, astronauts would need a way to repair it on site.

Bandyopadhyay first demonstrated the feasibility of this idea in 2011 when his team used 3D-printing to manufacture parts from lunar regolith, simulated crushed moon rock, for NASA. Since then, space agencies have embraced the technology, and International Space Station has its own 3D-printers to manufacture needed materials on site and for experiments.

For this study, Bandyopadhyay along with graduate students Ali Afrouzian and Kellen Traxel, used a powder-based 3D printer to mix the simulated Martian rock dust with a titanium alloy, a metal often used in space exploration for its strength and heat-resistant properties. As part of the process, a high-powered laser heated the materials to over 2,000 degrees Celsius (3,632 F). Then, the melted mix of Martian regolith-ceramic and metal material flowed onto a moving platform that allowed the researchers to create different sizes and shapes. After the material cooled down, the researchers tested it for strength and durability.

The ceramic material made from 100% Martian rock dust cracked as it cooled, but as Bandyopadhyay pointed out it could still make good coatings for radiation shields as cracks do not matter in that context. But just a little Martian dust, the mixture with 5% regolith, not only did not crack or bubble but also exhibited better properties than the titanium alloy alone, which meant it could be used to make lighter weight pieces that could still bear heavy loads.

"It gives you a better, higher strength and hardness material, so that can perform significantly better in some applications," he said.

This study is just a start, Bandyopadhyay said, and future research may yield better composites using different metals or 3D-printing techniques.

Read more at Science Daily

Bees use patterns -- not just colors -- to find flowers

Honeybees rely heavily on flower patterns -- not just colours -- when searching for food, new research shows.

A team led by the University of Exeter tested bee behaviour and built bee's-eye-view simulations to work out how they see flowers.

Honeybees have low-resolution vision (about 100 times lower than human vision), so they can only see a flower's pattern clearly when they are within few centimetres.

However, the new study shows bees can very effectively distinguish between different flowers by using a combination of colour and pattern.

In a series of tests, bees rarely ignored pattern -- suggesting colour alone does not lead them to flowers.

This may help to explain why some colours that are visible to bees are rarely produced by flowers in nature.

"We analysed a large amount of data on plants and bee behaviour," said Professor Natalie Hempel de Ibarra, from Exeter's Centre for Research in Animal Behaviour.

"By training and testing bees using artificial patterns of shape and colour, we found they relied flexibly on their ability to see both of these elements.

"Showing how insects see colour and learn colour patterns is important to understand how pollinators may, or may not, create evolutionary 'pressures' on the colours and patterns that flowers have evolved.

"Our findings suggest that flowers don't need to evolve too many different petal colours, because they can use patterns to diversify their displays so bees can tell them apart from other flowers."

One consistent feature identified in the study is that the outside edges of flowers usually contrast strongly with the plant's foliage -- while the centre of the flower does not have such a strong contrast with the foliage colour.

This could help bees quickly identify colour differences and navigate to flowers.

While flowers may be beautiful to humans, Professor Hempel de Ibarra stressed that understanding more about bees -- and the threats they face -- meant we need to see the world "through the eyes of a bee and the mind of a bee."

Read more at Science Daily

How tardigrades bear dehydration

Some species of tardigrades, or water bears as the tiny aquatic creatures are also known, can survive in different environments often hostile or even fatal to most forms of life. For the first time, researchers describe a new mechanism that explains how some tardigrades can endure extreme dehydration without dying. They explored proteins that form a gel during cellular dehydration. This gel stiffens to support and protect the cells from mechanical stress that would otherwise kill them. These proteins have also been shown to work in insect cells and even show limited functionality in human cultured cells.

Tardigrades often draw attention to themselves, despite being so tiny. Their uncanny ability to survive in situations that would kill most organisms has captured the public’s imagination. One could easily imagine that by decoding their secrets, we could apply the knowledge to ourselves to make humans more resilient to extreme temperatures, pressures, and even dehydration. This is just science fiction for now, but nevertheless, researchers, also captivated by the microscopic creatures, seek to understand the mechanisms responsible for their robustness, as this could bring other benefits too.

“Although water is essential to all life we know of, some tardigrades can live without it potentially for decades. The trick is in how their cells deal with this stress during the process of dehydration,” said Associate Professor Takekazu Kunieda from the University of Tokyo’s Department of Biological Sciences. “It’s thought that as water leaves a cell, some kind of protein must help the cell maintain physical strength to avoid collapsing in on itself. After testing several different kinds, we have found that cytoplasmic-abundant heat soluble (CAHS) proteins, unique to tardigrades, are responsible for protecting their cells against dehydration.”

Recent research into CAHS proteins reveals that they can sense when the cell encapsulating them becomes dehydrated, and that’s when they kick into action. CAHS proteins form gel-like filaments as they dry out. These form networks that support the shape of the cell as it loses its water. The process is reversible, so as the tardigrade cells become rehydrated, the filaments recede at a rate that doesn’t cause undue stress on the cell. Interestingly though, the proteins exhibited the same kind of action even when isolated from tardigrade cells.

“Trying to see how CAHS proteins behaved in insect and human cells presented some interesting challenges,” said lead author Akihiro Tanaka, a graduate student in the lab. “For one thing, in order to visualize the proteins, we needed to stain them so they show up under our microscopes. However, the typical staining method requires solutions containing water, which obviously confounds any experiment where water concentration is a factor one seeks to control for. So we turned to a methanol-based solution to get around this problem.”

Research on mechanisms related to dry preservation of cells or organisms could have many future applications. Kunieda and his team hope that through this new knowledge, researchers might find ways to improve the preservation of cell materials and biomolecules in a dry state. This could extend the shelf life of materials used for research, medicines with short expiry dates, or maybe even whole organs needed for transplants.

“Everything about tardigrades is fascinating. The extreme range of environments some species can survive leads us to explore never-before-seen mechanisms and structures. For a biologist, this field is a gold mine,” said Kunieda. “I’ll never forget New Year’s Day 2019, when I received an email from Tomomi Nakano, another author of the paper. She had been working late trying to see the condensation of CAHS proteins and observed the first CAHS filament networks in human cultured cells. I was astonished at seeing such clearly defined microscopic images of these. It was the first time I had seen such a thing. It was a very happy new year indeed!”

Read more at Science Daily

Faster in the Past: New seafloor images of West Antarctic Ice Sheet upend understanding of Thwaites Glacier retreat

The Thwaites Glacier in West Antarctica -- about the size of Florida -- has been an elephant in the room for scientists trying to make global sea level rise predictions.

This massive ice stream is already in a phase of fast retreat (a "collapse" when viewed on geological timescales) leading to widespread concern about exactly how much, or how fast, it may give up its ice to the ocean.

The potential impact of Thwaites' retreat is spine-chilling: a total loss of the glacier and surrounding icy basins could raise sea level from three to 10 feet.

A new study in Nature Geoscience led by marine geophysicist Alastair Graham at the University of South Florida's College of Marine Science adds cause for concern. For the first time, scientists mapped in high-resolution a critical area of the seafloor in front of the glacier that gives them a window into how fast Thwaites retreated and moved in the past.

The stunning imagery shows geologic features that are new to science, and also provides a kind of crystal ball to see into Thwaites' future. In people and ice sheets alike, past behavior is key to understanding future behavior.

The team documented more than 160 parallel ridges that were created, like a footprint, as the glacier's leading edge retreated and bobbed up and down with the daily tides.

"It's as if you are looking at a tide gauge on the seafloor," Graham said. "It really blows my mind how beautiful the data are."

Beauty aside, what's alarming is that the rate of Thwaites' retreat that scientists have documented more recently are small compared to the fastest rates of change in its past, said Graham.

To understand Thwaites' past retreat, the team analyzed the rib-like formations submerged 700 meters (just under half a mile) beneath the polar ocean and factored in the tidal cycle for the region, as predicted by computer models, to show that one rib must have been formed every single day.

At some point in the last 200 years, over a duration of less than six months, the front of the glacier lost contact with a seabed ridge and retreated at a rate of more than 2.1 kilometers per year (1.3 miles per year) -- twice the rate documented using satellites between 2011 and 2019.

"Our results suggest that pulses of very rapid retreat have occurred at Thwaites Glacier in the last two centuries, and possibly as recently as the mid-20th Century," Graham said.

"Thwaites is really holding on today by its fingernails, and we should expect to see big changes over small timescales in the future-even from one year to the next-once the glacier retreats beyond a shallow ridge in its bed," said marine geophysicist and study co-author Robert Larter from the British Antarctic Survey.

To collect the imagery and supporting geophysical data, the team, which included scientists from the United States, the United Kingdom and Sweden, launched a state-of-the-art orange robotic vehicle loaded with imaging sensors called 'Rán'from the R/V Nathaniel B. Palmer during an expedition in 2019.

Rán, operated by scientists at the University of Gothenburg in Sweden, embarked on a 20-hour mission that was as risky as it was serendipitous, Graham said. It mapped an area of the seabed in front of the glacier about the size of Houston -- and did so in extreme conditions during an unusual summer notable for its lack of sea ice.

This allowed scientists to access the glacier front for the first time in history.

"This was a pioneering study of the ocean floor, made possible by recent technological advancements in autonomous ocean mapping and a bold decision by the Wallenberg foundation to invest into this research infrastructure," said Anna Wåhlin, a physical oceanographer from the University of Gothenburg who deployed Rán at Thwaites. "The images Ran collected give us vital insights into the processes happening at the critical junction between the glacier and the ocean today."

"It was truly a once in a lifetime mission," said Graham, who said the team would like to sample the seabed sediments directly so they can more accurately date the ridge-like features.

"But the ice closed in on us pretty quickly and we had to leave before we could do that on this expedition," he said.

While many questions remain, one thing's for sure: It used to be that scientists thought of the Antarctic ice sheets as sluggish and slow to respond, but that's simply not true, said Graham.

"Just a small kick to Thwaites could lead to a big response," he said.

According to the United Nations, roughly 40 percent of the human population lives within 60 miles of the coast.

"This study is part of a cross-disciplinary collective effort to understand the Thwaites Glacier system better," said Tom Frazer, dean of the USF College of Marine Science, "and just because it's out of sight, we can't have Thwaites out of mind. This study is an important step forward in providing essential information to inform global planning efforts."

Read more at Science Daily

Astronomers show how terrain evolves on icy comets

With an eye toward a possible return mission years in the future, Cornell University astronomers have shown how smooth terrains -- a good place to land a spacecraft and to scoop up samples -- evolve on the icy world of comets.

By applying thermal models to data gathered by the Rosetta mission -- which caught up to the barbell-shaped Comet 67P/Churyumov-Gerasimenko almost a decade ago -- they show that the topography influences the comet's surface activity across hundreds of meters.

"You can have a uniform surface composition on comets and still have hotspots of activity," said lead author Abhinav S. Jindal, a graduate student in astronomy and member of the research group of Alexander Hayes, associate professor of astronomy. "The topography is driving the activity."

Comets are icy bodies made of dust, rocks and gas left over from the solar system's formation about 4.6 billion years ago, Jindal said. They form in the solar system's outer fringes and have spent eternity cruising through the dark, cosmic freezer of space, far from the sun's heat.

"Their chemistry has not changed much from when comets formed, making them 'time capsules' preserving primordial material from the birth of the solar system," Jindal said, explaining that these bodies likely seeded early Earth with water and key building blocks of life.

"As some of these comets have been pulled into the inner solar system," he said, "their surfaces undergo changes. Science is trying to understand the driving processes."

As Comet 67P loops its way back toward the sun, the body speeds by it to a point called perihelion -- its closest approach -- and the comet warms up. The Rosetta mission followed the comet as it rounded the sun and studied its activity. The smooth terrains serve as locations where the most changes were observed, making them key to grasping the surface's evolution.

Jindal and the researchers examined the evolution of 16 topographic depressions in the Imhotep region -- the largest smooth terrain deposit on 67P -- between June 5, 2015, when activity was first observed, and Dec. 6, 2015, when the final large-scale changes were observed.

The comet went through a process called sublimation -- in which the icy parts turned gaseous in the sun's heat. The comet's smooth Imhotep region showed a complex pattern of simultaneous eroding scarps (the steep edges of arc-shaped depressions) and material deposition.

Read more at Science Daily

Can 'random noise' unlock our learning potential?

Though many of us may seek a quiet place in which to study, 'noise' may play a key role in helping some people improve their learning potential.

Edith Cowan University (ECU) has investigated the effects of transcranial random noise stimulation (tRNS) in a variety of settings and found the technology could have many applications.

Despite its name, tRNS doesn't utilize noise in the everyday, auditory sense of the word.

Rather, it sees electrodes attached to the head so a weak current can pass through specific parts of the brain.

Study lead Dr Onno van der Groen said the study showed tRNS has promise as a tool to assist people with compromised learning capabilities.

"The effect on learning is promising: it can speed up learning and help people with neurological conditions," Dr van der Groen said.

"So, people with learning difficulties you can use it to enhance learning rate, for example.

"It's also been trialled on people with visual deficits, such as after stroke and traumatic brain injury.

"When you add this type of stimulation during learning, you get better performance, faster learning and better attention afterwards as well."

Forming new pathways

Dr van der Groen said tRNS works by allowing the brain to form new connections and pathways, a process known as neuroplasticity.

"If you learn something, there has to be neuroplastic changes in your brain, which allows you to learn this information," he said.

"And this is a tool to enhance this neuroplasticity."

Dr van der Groen said tRNS had two effects on the brain: the 'acute' effect, which allows a person to perform better while undergoing tRNS, and the modulating effect which saw lasting results.

"If you do 10 sessions of a visual perception task with the tRNS and then come back and do it again without it, you'll find you perform better than the control group who hasn't used it," he said.

"Limitless" potential?

The idea of expanding one's learning potential via tech such as tRNS raises many questions.

While it's most pertinent to those with deficiencies and difficulties in learning, it also begs the question as to whether a neurotypical person can take their intelligence to new levels, similar to the concept in the movie 'Limitless'.

Dr van der Groen says the potential is there, but there are also signs it won't create a 'new level' of intelligence.

"The question is, if you're neurotypical, are you already performing at your peak," he said.

"There's a case study where they tried to enhance the mathematical skills of a super mathematician; with him, it didn't have much of an impact on his performance, presumably because he is already a top performer in that area.

"But it could be used if you're learning something new."

Where it's headed

Though the technology is still in its infancy and people are only able to access tRNS by entering controlled trials, Dr van der Groen said its practicality and apparent safety meant there was a lot of potential for a range of applications.

"The concept is relatively simple," he said.

"It's like a battery: the current runs from plus to minus, but it goes through your head as well.

"We're working on a study where we send the equipment to people, and they apply everything themselves remotely.

"So in that regards, it's quite easy to use."

Scientists worldwide are also investigating tRNS' effects on perception, working memory, sensory processing and other aspects of behaviour, with the technology showing promise as a treatment for a range of clinical conditions.

"We're still trying to find out how best we can use it," Dr van der Groen said.

Read more at Science Daily

Scientists study tourists to protect great apes

Researchers are protecting great apes from diseases by studying the behaviour and expectations of tourists who visit them.

Humans are great apes, and this close genetic link makes non-human great apes (bonobos, chimpanzees, eastern gorillas, western gorillas and orangutans) vulnerable to our infectious diseases.

In the new study, by an international team including the University of Exeter, NOVA University Lisbon and Ugandan NGO Conservation Through Public Health, almost 1,000 tourists or potential future tourists completed an online questionnaire.

Willingness to comply with disease prevention measures like wearing a facemask varied depending on factors such as nationality, expectations about the visitor experience and whether people thought specific disease-risk measures were effective.

The study was conducted in the early stages of the COVID-19 pandemic, when the researchers also created the Protect Great Apes from Disease initiative.

"We have developed visitor education and guide-training materials for use in African sites of great ape tourism," said lead author Dr Ana Nuno, of NOVA University Lisbon and the University of Exeter.

"To do so, we first explored what factors seem to affect visitors' compliance with disease mitigation measures.

"This included asking them about their actions on previous visits, their willingness to comply in future and exploring what factors should be promoted to increase their willingness to follow recommendations.

"To do so, we adapted a tool from the health literature which is commonly used for understanding why individuals may or may not act in the face of a threat to health."

Dr Kim Hockings, from the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall, added: "Through this greater understanding of the visitors to wild African great ape tourism sites, we were able to identify ways of improving measures to reduce disease transmission.

"This is important not only for COVID-19 but other infectious diseases too, particularly at the early stages of future pandemics when information is generally limited but preventive action is required.

"In the face of growing threats from future pandemics, we must minimise disease transmission while ensuring that tourism and research promote long-term support for the conservation of great apes and their habitats as well as maximising benefits for local communities."

The questionnaire was completed by 420 past visitors and 569 potential future visitors (from 58 countries in total) to wild great ape tourism sites in Africa.

When compared to other disease-mitigation measures, visitors expressed less willingness to being vaccinated against COVID-19 (which, at the time the survey was conducted, had only just started being administered to very high-risk groups), wearing a facemask during trekking (although willing when viewing the apes) and quarantine after international travel before visiting great apes.

Believing that each specific measure was effective in preventing disease was key to respondents' willingness to follow that specific recommendation.

Read more at Science Daily

Simple measures can go a long way to combating air pollution in schools

Most UK primary schools experience levels of pollution which exceed the safe levels set out by the World Health Organization, yet simple measures can cut outdoor and indoor exposure of toxins by almost half, according to a new study from the University of Surrey.

Working with a select number of London schools, researchers from Surrey's Global Centre for Clean Air Research (GCARE) investigated whether putting up a green screen along the perimeter fence of a school, installing air purifiers in classrooms, and organising school street initiatives during pick-up and drop-off hours, improved air quality of classrooms and playgrounds. These initiatives were funded by Impact on Urban Health.

The researchers found that air purifiers in classrooms reduced indoor pollution concentrations by up to 57%, and the School Streets initiative, which stops motor vehicles driving past schools at the start and end of school days, reduced particle concentrations by up to 36%. Green screens at the school boundary reduced some of the most dangerous outdoor particle levels coming from roads by up to 44%, depending on wind conditions.

Prashant Kumar, founding Director of the Global Centre for Clean Air Research (GCARE) at the University of Surrey, said:

"Everybody, especially our children, deserves to live and work where the air is as clean and safe as possible. Unfortunately, the reality is far from ideal, with many of our schools unwittingly exposing children to harmful pollutants. The problem is particularly bad at schools near busy roads.

"Our research offers hope to many who care about this issue, as the results show that taking reasonable action can make a positive difference."

Ten million students worldwide spend 30% of their daily lives at school, with 70% of this time being spent indoors. Currently, 7,000 UK schools breach the World Health Organization's air quality limits, leaving children vulnerable to respiratory diseases, affected lung and brain health, behavioural problems, and increased risk of cancer.

Kate Langford, Programme Director of the Health Effects of Air pollution programme at Impact on Urban Health, funders of the research, said:

"Every child has the right to learn in an environment that keeps them safe and healthy. But, every day, children are exposed to dangerously high levels of air pollution in and around schools.

"Our partnership with Arup, Global Action Plan and the University of Surrey has shown there are practical ways that we can protect children in and around schools and can help guide schools to implement these solutions.

"These measures now need to be combined with efforts from local authorities at regional and national levels to improve air quality and create healthier places for children to live, learn and play."

Larissa Lockwood, Director of Clean Air at Global Action Plan, said:

"Schools should be safe places of learning, not places where students are at risk of health hazards. There is no safe level of air pollution, but children are particularly vulnerable to its impacts including the development of organs and their ability to learn. Services like the London Schools Pollution Helpdesk ensure that schools have access to advice on what they can do to reduce exposure to air pollution, including the measures tested in this research. But this needs to be rolled out nationally -- all children must be protected from the health effects of air pollution in their everyday lives."

Professor Prashant Kumar concluded:

"My simple plea to decision-makers in the UK is this: simple actions speak louder than words. By giving every school resources to implement one of the measures detailed in our research, they could make a world of difference to tens of thousands of children in this country."

Read more at Science Daily

Crime-scene technique identifies asteroid sites

Analysing the charred remains of plants can confirm the locations of asteroid strikes in the distant past, new research shows.

Based on estimates of crater-producing asteroid strikes in the last 11,650 years (known as the Holocene), only about 30% of impact sites have been located.

Until now, there has been no way to distinguish between normal land structures and very small asteroid craters unless pieces of iron meteorites were found nearby.

In the new study, an international team of researchers found that charcoal around craters is different from wildfire charcoal -- so analysing samples allows scientists to work out the origin of small craters.

"The properties of organisms turned into charcoal reflect the conditions in which they were killed," said lead author Dr Ania Losiak, from the Institute of Geological Sciences, Polish Academy of Sciences and the University of Exeter.

"Those conditions, such as the heat the wood was exposed to or the duration of the heating, leave tell-tale signs in the material's structure.

"For example, charcoal from low-energy surface fires, like burning bushes and leaves, has different properties than charcoal from high-intensity wildfires.

"Impact charcoals are very strange. They all look as if they were formed in much lower temperatures than wildfire charcoals, and they are all very similar to each other, while in a wildfire it is common to find strongly charred wood just next to barely affected branches."

Dr Losiak worked on the research as part of a Marie Sklodowska-Curie Individual Fellowship at the University of Exeter wildFIRE lab, led by Professor Claire Belcher.

The research team dug trenches in rims of four craters (Kaali Main and Kaali 2/8 in Estonia, Morasko in Poland, and Whitecourt in Canada).

"The differences between wildfire charcoal and impact charcoal proved to be dramatic and surprising," said Professor Belcher, part of Exeter's Global Systems Institute.

"While wildfire charcoal is considerably varied in its reflectivity, depending on the local conditions during the fire, impact charcoals showed uniform characteristics despite coming from completely different locations and being formed thousands of years apart.

"This presents an opportunity for geologists looking for unrecognised impact craters."

Professor Chris Herd, from the University of Alberta, said: "This study improves our understanding of environmental effects of small impact crater formation so that in the future, when we discover an asteroid a few metres across or more coming our way only a couple of weeks before the impact, we will be able to more precisely determine the size and type of evacuation zone necessary."

Read more at Science DailytAnalysing the charred remains of plants can confirm the locations of asteroid strikes in the distant past, new research shows.

Based on estimates of crater-producing asteroid strikes in the last 11,650 years (known as the Holocene), only about 30% of impact sites have been located.

Until now, there has been no way to distinguish between normal land structures and very small asteroid craters unless pieces of iron meteorites were found nearby.

In the new study, an international team of researchers found that charcoal around craters is different from wildfire charcoal -- so analysing samples allows scientists to work out the origin of small craters.

"The properties of organisms turned into charcoal reflect the conditions in which they were killed," said lead author Dr Ania Losiak, from the Institute of Geological Sciences, Polish Academy of Sciences and the University of Exeter.

"Those conditions, such as the heat the wood was exposed to or the duration of the heating, leave tell-tale signs in the material's structure.

"For example, charcoal from low-energy surface fires, like burning bushes and leaves, has different properties than charcoal from high-intensity wildfires.

"Impact charcoals are very strange. They all look as if they were formed in much lower temperatures than wildfire charcoals, and they are all very similar to each other, while in a wildfire it is common to find strongly charred wood just next to barely affected branches."

Dr Losiak worked on the research as part of a Marie Sklodowska-Curie Individual Fellowship at the University of Exeter wildFIRE lab, led by Professor Claire Belcher.

The research team dug trenches in rims of four craters (Kaali Main and Kaali 2/8 in Estonia, Morasko in Poland, and Whitecourt in Canada).

"The differences between wildfire charcoal and impact charcoal proved to be dramatic and surprising," said Professor Belcher, part of Exeter's Global Systems Institute.

"While wildfire charcoal is considerably varied in its reflectivity, depending on the local conditions during the fire, impact charcoals showed uniform characteristics despite coming from completely different locations and being formed thousands of years apart.

"This presents an opportunity for geologists looking for unrecognised impact craters."

Professor Chris Herd, from the University of Alberta, said: "This study improves our understanding of environmental effects of small impact crater formation so that in the future, when we discover an asteroid a few metres across or more coming our way only a couple of weeks before the impact, we will be able to more precisely determine the size and type of evacuation zone necessary."

Read more at Science Daily

From wound healing to regeneration

The phenomenon of regeneration was discovered over 200 years ago in the freshwater polyp Hydra. Until now, however, it was largely unclear how the orderly regeneration of lost tissues or organs is activated after injury. In its investigations of Hydra, an interdisciplinary research team at Heidelberg University was able to show how wound healing signals released upon injury are converted into specific signals of pattern formation and cell differentiation. Essential components are the mitogen-activated protein kinases (MAPK) and the Wnt signalling pathway -- molecular mechanisms that have remained relatively unchanged throughout evolution.

The ability to regenerate varies widely in animals. Most mammals and vertebrates have only limited regeneration capacity, while basal and simple animals that emerged early in evolution, like cnidarians and planarians, can regenerate their whole body. In all cases, the process of regeneration begins with wound healing. The cells at the site of injury proliferate and form an undifferentiated mass -- a blastema -- from which the missing structures are re-patterned. This activates genetic processes that also control embryonic development. To determine the molecular mechanisms involved, the research team led by Prof. Dr Thomas W. Holstein studied the freshwater polyp Hydra to understand the basic features of this activation of regeneration.

The core of their investigations is the doctoral thesis of Anja Tursch. She repeated the key experiment of Geneva naturalist Abraham Trembley (1710 to 1784) which led him to discover the regeneration phenomenon. The Hydra polyp is bisected, prompting the upper half to regenerate a new "head" and the lower half a new "foot" -- hence totally different body parts can grow from the exact same tissue at the cut surface in the middle. Building on their previous work on Hydra regeneration, the researchers at the Centre for Organismal Studies (COS) of Heidelberg University have now shown how this is possible.

Regardless of where it occurs, any damage triggers nonspecific signals for an injury response, i.e. wound healing, via calcium ions and the production of reactive oxygen species. The signals are transmitted intracellularly by three mitogen-activated protein kinases -- p38, JNKs, and ERK. Activation of these three molecules is required for both head and foot regeneration. Wnt signalling pathways are then activated that are important during embryonic development for the formation of rudimentary organs and the body axis. The generic signals of wound healing are thus transferred into position-specific signals of patterning and cell differentiation for regeneration.

"Our experiments show that the Wnt signalling pathway is a main component of the initially general injury response and, depending on signal strength, directs the tissue toward head or foot development," explains Prof. Holstein. This is why, in the case of MAPK inhibition, the otherwise absent regeneration can be induced by artificially generated, recombinant Wnt proteins. "It was also surprising that in middle body parts that had both head and foot removed, heads can be induced at both ends in this way," adds Dr Suat Özbek, a member of Prof. Holstein's "Molecular Evolution and Genomics" research group at the COS.

Read more at Science Daily