Dynamic rivers contributed to Amazon's rich bird diversity

 One of the most contentious questions in evolutionary biology is, how did the Amazon become so rich in species? A new study focused on birds examines how the movements of rivers in the Amazon have contributed to that area's exceptional biological diversity. The research team, led by the American Museum of Natural History, found that as small river systems change over time, they spur the evolution of new species. The findings also reveal previously unknown bird species in the Amazon that are only found in small areas next to these dynamic river systems, putting them at high risk of imminent extinction. The study is detailed today in the journal Science Advances.

The lowland rainforests of the Amazon River basin harbor more diversity than any other terrestrial ecosystem on the planet. It is also a globally important biome containing about 18 percent of all trees on Earth and carrying more fresh water than the next seven largest river basins combined. Researchers have long wondered and hotly debate how the Amazon's rich biodiversity arose and accumulated.

"Early evolutionary biologists like Alfred Russel Wallace noticed that many species of primates and birds differ across opposite riverbanks in the Amazon, and ornithologists now know that rivers are associated -- in one way or another -- with the origin of many avian species," said the study's lead author Lukas Musher, a postdoctoral researcher at the Academy of Natural Sciences of Drexel University and a recent comparative biology Ph.D. graduate of the American Museum of Natural History's Richard Gilder Graduate School. "Moreover, accumulating geological evidence has suggested that these rivers are highly dynamic, moving around the South American landscape over relatively short time periods, on the order of thousands or tens of thousands of years."

To investigate how the movement of rivers across the landscape has influenced the accumulation of bird species in the Amazon, the researchers sequenced the genomes of six species of Amazonian birds.

"Even though birds can fly, our study confirmed that current rivers across the Southern Amazon rainforest, even relatively small ones, are highly effective at isolating populations of these six species, which leads to genomic divergence and ultimately speciation," said the study's senior author Joel Cracraft, Lamont Curator and curator-in-charge in the Museum's Department of Ornithology.

However, because these rivers move around the landscape at different time scales, their movements can have varying outcomes for bird species: when river rearrangements occur quickly, populations of birds on each side can merge before they've had time to differentiate; when river changes happen slowly, species have a longer time to diverge from one another; and when rivers change at intermediate rates, bird populations diverge and then join back together and co-occur when a river moves.

The scientists also identified distinct populations of birds that should be described as separate species but have been considered a single species until now.

"Though we know Amazonian biodiversity is unmatched by any other terrestrial ecosystem, we demonstrated that its species richness may be greatly underestimated even in well-studied groups such as birds," Musher said. "Our results corroborate those of other studies that have reported fine-scale patterns of diversity across the southern Amazon basin -- a region threatened by rapid and ongoing deforestation -- yet this diversity is generally unrecognized. Many of the distinct populations are relatively young and endemic to a small Amazonian region, meaning that a large portion of the Amazon's birds may be threatened with loss to imminent extinction."

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CRISPR gene editing reveals biological mechanism behind common blood disorder

UNSW researchers have used CRISPR gene editing -- a type of 'molecular scissors' -- to understand how deletions in one area of the genome can affect the expression of nearby genes. The work, led by UNSW Associate Professor Kate Quinlan and Professor Merlin Crossley, together with collaborators from the US, will help researchers investigate new therapeutic approaches for one of the world's most devastating genetic blood disorders -- sickle cell disease.

Asymptomatic sickle cell disease patients actually lack a tiny part of the genome, scientists have shown.

The team's findings are published today in academic journal Blood. (Just last week, A/Prof. Quinlan and Prof. Crossley received a $412,919 ARC linkage grant to fund a collaboration between UNSW Sydney and CSL that follows on from the work described in this paper.)

"Sickle cell disease and beta thalassemia, a closely related disease, are inherited genetic conditions that affect red blood cells. They are fairly common worldwide -- over 318,000 infants with these conditions are born every year, and haemoglobin disorders cause 3 per cent of deaths in children aged under five years worldwide," says co-lead author A/Prof. Quinlan.

Genetic mutations -- specifically, a defect in the adult globin gene -- are responsible for the disorders. The mutant genes affect the production of haemoglobin, the protein in red blood cells that carries oxygen around our bodies.

"Interestingly, when children are born, they don't show disease symptoms at first, even if they have the mutations, because at that stage, they're still expressing foetal globin and not yet adult globin. That's because we have different haemoglobin genes that we express at different stages of development," says A/Prof. Quinlan.

"As the foetal globin gets turned off, and adult globin gets turned on -- which happens within about the first year of life -- the symptoms start to manifest."

When that happens, the red blood cells take on unusual, sickled shapes and block small blood vessels, causing pain, organ damage, and premature death. The disease is particularly common in tropical countries, and in people from places where malaria is endemic.

"The goal of our research is finding out how we can reverse the foetal to adult globin switch, so that patients continue to express foetal globin throughout life, rather than the mutant adult globin genes that cause blood cells to become stiff and block vessels," says A/Prof. Quinlan.

Interestingly, this already happens in some people with sickle cell disease: thanks to another, beneficial genetic mutation, a rare subset of patients keeps the foetal globin gene 'on' throughout their life and are protected from sickle cell symptoms.

"In these patients, the persistent expression of foetal globin effectively compensates for the defective adult globin -- but up until this piece of research, we didn't really understand the process that led to this incredible advantage," A/Prof. Quinlan says.

'Deleting' genes with CRISPR

To get to the bottom of what's going on in these lucky people's genome, UNSW PhD student Sarah Topfer compiled data on the rare families that express foetal globin throughout life.

"As a first step, Sarah compared deletions in lots of different patients' genomes -- essentially, she looked to see if any shared element was missing in all of them. What do these patients have in common? She found one very small region was deleted in all these patients' genomes."

Sarah then used CRISPR gene editing to replicate some of these big patient deletions -- and the small deleted bit they all had in common -- in cell lines in the lab.

"CRISPR allows us to 'cut' bits of DNA out of cells grown in the lab, to modify genes and see what happens as a result -- it's essentially a tool to figure out what genes do inside living cells," A/Prof. Quinlan says.

"We found that deleting just that one little bit was sufficient to make foetal globin go up and adult globin down -- which suggests that we have found the key mechanism that can explain why foetal globin levels remains high in these asymptomatic patients," A/Prof. Quinlan says.

"Effectively, by deleting the adult globin 'on switch', we made the foetal globin 'on switch' active."

Prof. Quinlan says the results were unexpected.

"It was surprising to see the findings -- many people have studied these mutations for many years, so the idea that there'd be one unifying hypothesis that could explain them rather than them all working through different mechanisms will be surprising for the field.

"While we went in with the hypothesis that there might be one mechanism, we didn't expect it to come out so cleanly -- we thought that perhaps it would be more complicated than what we'd initially thought."

The CRISPR revolution and potential therapies

Co-lead author Prof. Crossley, who is also UNSW's Deputy Vice-Chancellor, Academic & Student Life, says it was impossible to test this model prior to the advent of CRISPR gene editing.

"Our group has specialised in using this new technology to understand globin gene switching," Prof. Crossley says. "Australia now has a significant number of people with either sickle cell disease or thalassemia.

"The work, supported by the National Health and Medical Research Council, is an important example of how the CRISPR gene editing revolution is accelerating scientific understanding and will deliver new therapies to the clinic."

The scientists say the work revealed today is improving our fundamental understanding of the mechanism behind sickle cell disease.

"What this really helps us to do is understand this process of turning off foetal globin and turning on adult globin and how we could reverse that, so that we can use this understanding of the mechanism to help us look for new therapeutic approaches -- it's a key piece of the puzzle," A/Prof. Quinlan says.

Some of Prof. Crossley's team's previous discoveries in the field are informing clinical trials already -- by using beneficial mutations they've discovered in the past that could lead to therapies for these disorders.

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Differences between the Moon’s near and far sides linked to colossal ancient impact

The face that the Moon shows to Earth looks far different from the one it hides on its far side. The nearside is dominated by the lunar mare -- the vast, dark-colored remnants of ancient lava flows. The crater-pocked far side, on the other hand, is virtually devoid of large-scale mare features. Why the two sides are so different is one of the Moon's most enduring mysteries.

Now, researchers have a new explanation for the two-faced Moon -- one that relates to a giant impact billions of years ago near the Moon's south pole.

A new study published in the journal Science Advances shows that the impact that formed the Moon's giant South Pole-Aitken (SPA) basin would have created a massive plume of heat that propagated through the lunar interior. That plume would have carried certain materials -- a suite of rare-Earth and heat-producing elements -- to the Moon's nearside. That concentration of elements would have contributed to the volcanism that created the nearside volcanic plains.

"We know that big impacts like the one that formed SPA would create a lot of heat," said Matt Jones, a Ph.D. candidate at Brown University and the study's lead author. "The question is how that heat affects the Moon's interior dynamics. What we show is that under any plausible conditions at the time that SPA formed, it ends up concentrating these heat-producing elements on the nearside. We expect that this contributed to the mantle melting that produced the lava flows we see on the surface."

The study was a collaboration between Jones and his advisor Alexander Evans, an assistant professor at Brown, along with researchers from Purdue University, the Lunar and Planetary Science Laboratory in Arizona, Stanford University and NASA's Jet Propulsion Laboratory.

The differences between the near and far sides of the Moon were first revealed in the 1960s by the Soviet Luna missions and the U.S. Apollo program. While the differences in volcanic deposits are plain to see, future missions would reveal differences in the geochemical composition as well. The nearside is home to a compositional anomaly known as the Procellarum KREEP terrane (PKT) -- a concentration of potassium (K), rare earth elements (REE), phosphorus (P), along with heat-producing elements like thorium. KREEP seems to be concentrated in and around Oceanus Procellarum, the largest of the nearside volcanic plains, but is sparse elsewhere on the Moon.

Some scientists have suspected a connection between the PKT and the nearside lava flows, but the question of why that suite of elements was concentrated on the nearside remained. This new study provides an explanation that is connected to the South Pole-Aitken basin, the second largest known impact crater in the solar system.

For the study, the researchers conducted computer simulations of how heat generated by a giant impact would alter patterns of convection in the Moon's interior, and how that might redistribute KREEP material in the lunar mantle. KREEP is thought to represent the last part of the mantle to solidify after the Moon's formation. As such, it likely formed the outermost layer of mantle, just beneath the lunar crust. Models of the lunar interior suggest that it should have been more or less evenly distributed beneath the surface. But this new model shows that the uniform distribution would be disrupted by the heat plume from the SPA impact.

According to the model, the KREEP material would have ridden the wave of heat emanating from the SPA impact zone like a surfer. As the heat plume spread beneath the Moon's crust, that material was eventually delivered en masse to the nearside. The team ran simulations for a number of different impact scenarios, from dead-on hit to a glancing blow. While each produced differing heat patterns and mobilized KREEP to varying degrees, all created KREEP concentrations on the nearside, consistent with the PKT anomaly.

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Hunting for gravitational waves from monster black holes

Our universe is a chaotic sea of ripples in space-time called gravitational waves. Astronomers think waves from orbiting pairs of supermassive black holes in distant galaxies are light-years long and have been trying to observe them for decades, and now they're one step closer thanks to NASA's Fermi Gamma-ray Space Telescope.

Fermi detects gamma rays, the highest-energy form of light. An international team of scientists examined over a decade of Fermi data collected from pulsars, rapidly rotating cores of stars that exploded as supernovae. They looked for slight variations in the arrival time of gamma rays from these pulsars, changes which could have been caused by the light passing through gravitational waves on the way to Earth. But they didn't find any.

While no waves were detected, the analysis shows that, with more observations, these waves may be within Fermi's reach.

"We kind of surprised ourselves when we discovered Fermi could help us hunt for long gravitational waves," said Matthew Kerr, a research physicist at the U.S. Naval Research Laboratory in Washington. "It's new to the fray -- radio studies have been doing similar searches for years. But Fermi and gamma rays have some special characteristics that together make them a very powerful tool in this investigation."

The results of the study, co-led by Kerr and Aditya Parthasarathy, a researcher at the Max Planck Institute for Radio Astronomy in Bonn, Germany, were published online by the journal Science on April 7.

When massive objects accelerate, they produce gravitational waves traveling at light speed. The ground-based Laser Interferometer Gravitational Wave Observatory -- which first detected gravitational waves in 2015 -- can sense ripples tens to hundreds of miles long from crest to crest, which roll past Earth in just fractions of a second. The upcoming space-based Laser Interferometer Space Antenna will pick up waves millions to billions of miles long.

Kerr and his team are searching for waves that are light-years, or trillions of miles, long and take years to pass Earth. These long ripples are part of the gravitational wave background, a random sea of waves generated in part by pairs of supermassive black holes in the centers of merged galaxies across the universe.

To find them, scientists need galaxy-sized detectors called pulsar timing arrays. These arrays use specific sets of millisecond pulsars, which rotate as fast as blender blades. Millisecond pulsars sweep beams of radiation, from radio to gamma rays, past our line of sight, appearing to pulse with incredible regularity -- like cosmic clocks.

As long gravitational waves pass between one of these pulsars and Earth, they delay or advance the light arrival time by billionths of a second. By looking for a specific pattern of pulse variations among pulsars of an array, scientists expect they can reveal gravitational waves rolling past them.

Radio astronomers have been using pulsar timing arrays for decades, and their observations are the most sensitive to these gravitational waves. But interstellar effects complicate the analysis of radio data. Space is speckled with stray electrons. Across light-years, their effects combine to bend the trajectory of radio waves. This alters the arrival times of pulses at different frequencies. Gamma rays don't suffer from these complications, providing both a complementary probe and an independent confirmation of the radio results.

"The Fermi results are already 30% as good as the radio pulsar timing arrays when it comes to potentially detecting the gravitational wave background," Parthasarathy said. "With another five years of pulsar data collection and analysis, it'll be equally capable with the added bonus of not having to worry about all those stray electrons."

Within the next decade, both radio and gamma-ray astronomers expect to reach sensitivities that will allow them to pick up gravitational waves from orbiting pairs of monster black holes.

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Can artificial intelligence reveal why languages change over time?

The way we speak today isn't the way that people talked thousands -- or even hundreds -- of years ago. William Shakespeare's line, "to thine own self be true," is today's "be yourself." New speakers, ideas, and technologies all seem to play a role in shifting the ways we communicate with each other, but linguists don't always agree on how and why languages change. Now, a new study of American Sign Language adds support to one potential reason: sometimes, we just want to make our lives a little easier.

Deaf studies scholar Naomi Caselli and a team of researchers found that American Sign Language (ASL) signs that are challenging to perceive -- those that are rare or have uncommon handshapes -- are made closer to the signer's face, where people often look during sign perception. By contrast, common ones, and those with more routine handshapes, are made further away from the face, in the perceiver's peripheral vision. Caselli, a Boston University Wheelock College of Education & Human Development assistant professor, says the findings suggest that ASL has evolved to be easier for people to recognize signs. The results were published in Cognition.

"Every time we use a word, it changes just a little bit," says Caselli, who's also codirector of the BU Rafik B. Hariri Institute for Computing and Computational Science & Engineering's AI and Education Initiative. "Over long periods of time, words with uncommon handshapes have evolved to be produced closer to the face and, therefore, are easier for the perceiver to see and recognize."

Although studying the evolution of language is complex, says Caselli, "you can make predictions about how languages might change over time, and test those predictions with a current snapshot of the language."

With researchers from Syracuse University and Rochester Institute of Technology, she looked at the evolution of ASL with help from an artificial intelligence (AI) tool that analyzed videos of more than 2,500 signs from ASL-LEX, the world's largest interactive ASL database. Caselli says they began by using the AI algorithm to estimate the position of the signer's body and limbs.

"We feed the video into a machine learning algorithm that uses computer vision to figure out where key points on the body are," says Caselli. "We can then figure out where the hands are relative to the face in each sign." The researchers then match that with data from ASL-LEX -- which was created with help from the Hariri Institute's Software & Application Innovation Lab -- about how often the signs and handshapes are used. They found, for example, that many signs that use common handshapes, such as the sign for children -- which uses a flat, open hand -- are produced further from the face than signs that use rare handshapes, like the one for light (see videos).

This project is part of a new and growing body of work connecting computing and sign language at BU.

"The team behind these projects is dynamic, with signing researchers working in collaboration with computer vision scientists," says Lauren Berger, a Deaf scientist and postdoctoral fellow at BU who works on computational approaches to sign language research. "Our varying perspectives, anchored by the oversight of researchers who are sensitive to Deaf culture, helps prevent cultural and language exploitation just for the sake of pushing forward the cutting edge of technology and science."

Understanding how sign languages work can help improve Deaf education, says Caselli, who hopes the latest findings also bring attention to the diversity in human languages and the extraordinary capabilities of the human mind.

Read more at Science Daily

Air pollution responsible for 180,000 excess deaths in tropical cities

The international team of scientists aimed to address data gaps in air quality for 46* future megacities in Africa, Asia and the Middle East using space-based observations from instruments onboard NASA and European Space Agency (ESA) satellites for 2005 to 2018.

Published today in Science Advances, the study reveals rapid degradation in air quality and increases in urban exposure to air pollutants hazardous to health. Across all the cities, the authors found significant annual increases in pollutants directly hazardous to health of up to 14% for nitrogen dioxide (NO2) and up to 8% for fine particles (PM2.5), as well as increases in precursors of PM2.5 of up to 12% for ammonia and up to 11% for reactive volatile organic compounds.

The researchers attributed this rapid degradation in air quality to emerging industries and residential sources like road traffic, waste burning, and widespread use of charcoal and fuelwood.

Lead author Dr Karn Vohra (UCL Geography), who completed the study as a PhD student at the University of Birmingham, said: "Open burning of biomass for land clearance and agricultural waste disposal has in the past overwhelmingly dominated air pollution in the tropics. Our analysis suggests we're entering a new era of air pollution in these cities, with some experiencing rates of degradation in a year that other cities experience in a decade."

The scientists also found 1.5- to 4- fold increases in urban population exposure to air pollution over the study period in 40 of the 46 cities for NO2 and 33 of the 46 cities for PM2.5., caused by a combination of population growth and rapid deterioration in air quality.

According to the study, the increase in the number of people dying prematurely from exposure to air pollution was highest in cities in South Asia, in particular Dhaka, Bangladesh (totalling 24,000 people), and the Indian cities of Mumbai, Bangalore, Kolkata, Hyderabad, Chennai, Surat, Pune and Ahmedabad (totalling 100,000 people).

The researchers say that while the number of deaths in tropical cities in Africa are currently lower due to recent improvements in healthcare across the continent resulting in a decline in overall premature mortality, the worst effects of air pollution on health will likely occur in the coming decades.

Study co-author Dr Eloise Marais (UCL Geography) said: "We continue to shift air pollution from one region to the next, rather than learning from errors of the past and ensuring rapid industrialisation and economic development don't harm public health. We hope our results will incentivise preventative action in the tropics."

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Astronomers detect 'galactic space laser'

A powerful radio-wave laser, called a 'megamaser', has been observed by the MeerKAT telescope in South Africa.

The record-breaking find is the most distant megamaser of its kind ever detected, at about five billion light years from Earth.

The light from the megamaser has travelled 58 thousand billion billion (58 followed by 21 zeros) kilometres to Earth.

The discovery was made by an international team of astronomers led by Dr Marcin Glowacki, who previously worked at the Inter-University Institute for Data Intensive Astronomy and the University of the Western Cape in South Africa.

Dr Glowacki, who is now based at the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, said megamasers are usually created when two galaxies violently collide in the Universe.

"When galaxies collide, the gas they contain becomes extremely dense and can trigger concentrated beams of light to shoot out," he said.

"This is the first hydroxyl megamaser of its kind to be observed by MeerKAT and the most distant seen by any telescope to date.

"It's impressive that, with just a single night of observations, we've already found a record-breaking megamaser. It shows just how good the telescope is."

The record-breaking object was named 'Nkalakatha' [pronounced ng-kuh-la-kuh-tah] -- an isiZulu word meaning "big boss."

Dr Glowacki said the megamaser was detected on the first night of a survey involving more than 3000 hours of observations by the MeerKAT telescope.

The team is using MeerKAT to observe narrow regions of the sky extremely deeply and will measure atomic hydrogenin galaxies from the distant past to now. The combination of studying hydroxl masers and hydrogen will help astronomers better understand how the Universe has evolved over time.

"We have follow-up observations of the megamaser planned and hope to make many more discoveries," Dr Glowacki said.

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Astronomers have spotted the farthest galaxy ever

An international team of astronomers, including researchers at the Center for Astrophysics | Harvard & Smithsonian, has spotted the most distant astronomical object ever: a galaxy.

Named HD1, the galaxy candidate is some 13.5 billion light-years away and is described Thursday in the Astrophysical Journal. In an accompanying paper published in the Monthly Notices of the Royal Astronomical Society Letters, scientists have begun to speculate exactly what the galaxy is.

The team proposes two ideas: HD1 may be forming stars at an astounding rate and is possibly even home to Population III stars, the universe's very first stars -- which, until now, have never been observed. Alternatively, HD1 may contain a supermassive black hole about 100 million times the mass of our Sun.

"Answering questions about the nature of a source so far away can be challenging," says Fabio Pacucci, lead author of the MNRAS study, co-author in the discovery paper on ApJ, and an astronomer at the Center for Astrophysics. "It's like guessing the nationality of a ship from the flag it flies, while being faraway ashore, with the vessel in the middle of a gale and dense fog. One can maybe see some colors and shapes of the flag, but not in their entirety. It's ultimately a long game of analysis and exclusion of implausible scenarios."

HD1 is extremely bright in ultraviolet light. To explain this, "some energetic processes are occurring there or, better yet, did occur some billions of years ago," Pacucci says.

At first, the researchers assumed HD1 was a standard starburst galaxy, a galaxy that is creating stars at a high rate. But after calculating how many stars HD1 was producing, they obtained "an incredible rate -- HD1 would be forming more than 100 stars every single year. This is at least 10 times higher than what we expect for these galaxies."

That's when the team began suspecting that HD1 might not be forming normal, everyday stars.

"The very first population of stars that formed in the universe were more massive, more luminous and hotter than modern stars," Pacucci says. "If we assume the stars produced in HD1 are these first, or Population III, stars, then its properties could be explained more easily. In fact, Population III stars are capable of producing more UV light than normal stars, which could clarify the extreme ultraviolet luminosity of HD1."

A supermassive black hole, however, could also explain the extreme luminosity of HD1. As it gobbles down enormous amounts of gas, high energy photons may be emitted by the region around the black hole.

If that's the case, it would be by far the earliest supermassive black hole known to humankind, observed much closer in time to the Big Bang compared to the current record-holder.

"HD1 would represent a giant baby in the delivery room of the early universe," says Avi Loeb an astronomer at the Center for Astrophysics and co-author on the MNRAS study. "It breaks the highest quasar redshift on record by almost a factor of two, a remarkable feat."

HD1 was discovered after more than 1,200 hours of observing time with the Subaru Telescope, VISTA Telescope, UK Infrared Telescope and Spitzer Space Telescope.

"It was very hard work to find HD1 out of more than 700,000 objects," says Yuichi Harikane, an astronomer at the University of Tokyo who discovered the galaxy. "HD1's red color matched the expected characteristics of a galaxy 13.5 billion light-years away surprisingly well, giving me a little bit of goosebumps when I found it."

The team then conducted follow-up observations using the Atacama Large Millimeter/submillimeter Array (ALMA) to confirm the distance, which is 100 million light years further than GN-z11, the current record-holder for the furthest galaxy.

Using the James Webb Space Telescope, the research team will soon once again observe HD1 to verify its distance from Earth. If current calculations prove correct, HD1 will be the most distant -- and oldest -- galaxy ever recorded.

The same observations will allow the team to dig deeper into HD1's identity and confirm if one of their theories is correct.

Read more at Science Daily

New link between greenhouse gasses and sea level rise

A new study provides the first evidence that rising greenhouse gases have a long-term warming effect on the Amundsen Sea in West Antarctica. Scientists from British Antarctic Survey (BAS) say that while others have proposed this link, no one has been able to demonstrate it.

Ice loss from the West Antarctic Ice Sheet in the Amundsen Sea is one of the fastest growing and most concerning contributions to global sea level rise. If the West Antarctic Ice Sheet were to melt, global sea levels could rise by up to three metres. The patterns of ice loss suggest that the ocean may have been warming in the Amundsen Sea over the past one hundred years, but scientific observations of the region only began in 1994.

In the study -- published in the journal Geophysical Research Letters -- oceanographers used advanced computer modelling to simulate the response of the ocean to a range of possible changes in the atmosphere between 1920-2013.

The simulations show the Amundsen Sea generally became warmer over the century. This warming corresponds with simulated trends in wind patterns in the region which increase temperatures by driving warm water currents towards and beneath the ice. Rising greenhouse gases are known to make these wind patterns more likely, and so the trend in winds is thought to be caused in part by human activity.

This study supports theories that ocean temperatures in the Amundsen Sea have been rising since before records began. It also provides the missing link between ocean warming and wind trends which are known to be partly driven by greenhouse gasses. Ocean temperatures around the West Antarctic Ice Sheet will probably continue to rise if greenhouse gas emissions increase, with consequences for ice melt and global sea levels. These findings suggest, however, that this trend could be curbed if emissions are sufficiently reduced and wind patterns in the region are stabilised.

Dr Kaitlin Naughten, ocean-ice modeller at BAS and lead author of this study, says,

"Our simulations show how the Amundsen Sea responds to long-term trends in the atmosphere, specifically the Southern Hemisphere westerly winds. This raises concerns for the future because we know these winds are affected by greenhouse gases. However, it should also give us hope, because it shows that sea level rise is not out of our control."

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Century-old malaria parasite puzzle solved as ape origin traced

Scientists have solved a 100-year-old mystery about the evolutionary links between malaria parasites that infect humans and chimpanzees.

They have discovered that the parasite P. malariae - one of six species that spreads malaria among humans - originated in African apes before evolving to infect people.

While it is often associated with mild disease, if untreated P. malariae can cause long-lasting, chronic infections that may last a lifetime, researchers say.

The evolutionary puzzle has its origins in the 1920s when scientists identified chimpanzees infected by parasites that appeared identical to P. malariae under a microscope.

It was thought both parasites belonged to the same species, but - until now - this could not be verified as the genetic make-up of the chimpanzee strain had never been studied.

Now, scientists at the University of Edinburgh, in collaboration with colleagues at the University of Pennsylvania, USA, have used leading edge techniques to study the parasites' DNA.

They have found that there are, in fact, three distinct species. One species - P. malariae - infects mainly humans, while the two others infect apes.

One of the two ape-infecting parasites was found in chimpanzees, gorillas and bonobos across Central and West Africa. This previously unknown species is only distantly related to the human parasite.

The other ape parasite is much more closely related to the one that infects humans. Knowing this enabled researchers to make detailed comparisons of the genetic diversity of the two species.

This revealed that the human malaria parasite population went through a genetic bottleneck, where its population temporarily shrank and most of its genetic variation was lost.

A likely explanation for this is that P. malariae was originally an ape parasite, but a small number of parasites switched hosts to begin infecting humans, the team says.

The study, published in the journal Nature Communications, was funded by the National Institutes of Health.

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Study reveals the dynamics of human milk production

For the first time, MIT researchers have performed a large-scale, high-resolution study of the cells in breast milk, allowing them to track how these cells change over time in nursing mothers.

By analyzing human breast milk produced between three days and nearly two years after childbirth, the researchers were able to identify a variety of changes in gene expression in mammary gland cells. Some of these changes were linked to factors such as hormone levels, illness of the mother or baby, the mother starting birth control, and the baby starting daycare.

"We were able to take this really long view of lactation that other studies haven't really done, and we showed that milk does change over the entire course of lactation, even after years of milk production," says Brittany Goods, a former MIT postdoc who is now an assistant professor of engineering at Dartmouth College, and one of the senior authors of the study.

The researchers hope that their findings will lay the groundwork for more in-depth studies of how breast milk changes over time. Such studies could eventually yield new ways to boost mothers' milk production or to improve the composition of infant formula.

Bonnie Berger, the Simons Professor of Mathematics at MIT and head of the Computation and Biology group at the Computer Science and Artificial Intelligence Laboratory (CSAIL), is a senior author of the study, as is Alex Shalek, an associate professor of chemistry at MIT and a member of the Institute for Medical Engineering and Science (IMES); the Koch Institute for Integrative Cancer Research; the Ragon Institute of MGH, MIT and Harvard; and the Broad Institute of Harvard and MIT.

MIT graduate student Sarah Nyquist is the lead author of the paper, which appears this week in the Proceedings of the National Academy of Sciences.

Cellular changes

Human mammary glands can produce more than a liter of milk in a day, for months or years after childbirth. Studying how mammary gland cells accomplish this feat has been difficult in humans because the tissue itself can't be biopsied or otherwise accessed during lactation. However, recent studies have shown that breast milk contains many cells from the mammary gland, offering a noninvasive way to study these cells.

For this study, the MIT team collected breast milk samples from 15 nursing mothers. Each donor provided samples at multiple time points, ranging from three to 632 days after giving birth. The researchers also collected information about health and lifestyle changes that occurred throughout the lactation period.

The researchers isolated more than 48,000 cells from 50 samples and analyzed them using single-cell RNA-sequencing, a technology that can determine which genes are being expressed in a cell at a given moment in time. This analysis revealed 10 types of cells -- a population of fibroblast cells, two types of epithelial cells, and seven types of immune cells.

More than half of the immune cells that they found were macrophages. These cells appear to express genes that help make the mammary gland more tolerant of the milk proteins that they are producing, so they don't trigger an immune response. The researchers also found populations of B cells, T cells, and other immune cells, but their numbers were too small to do any in-depth studies of their functions.

By far the most abundant cells that they found were lactocytes, which are a type of epithelial cell. These cells expressed many genes for proteins that are found in breast milk, such as lactalbumin, as well as transporters needed to secrete milk proteins, micronutrients, fat, and other breast milk components.

Among the lactocytes, the researchers identified one cluster of cells that appears to be the primary producer of milk, and another that plays more of a structural role in the mammary gland. Each of these cell types could be divided into further subtypes, which the researchers hypothesize may be specialized for particular roles.

As time went on, the researchers found that the proportion of lactocytes involved in milk production went down, while the proportion involved in structural support went up. At the same time, genes involved in responding to the hormone prolactin became more active in the milk-producing lactocytes but dropped off in structural lactocytes. The researchers theorize that these changes may be related to the changing nutritional needs of infants as they grow.

"This study, along with some other studies that are out there, paves the way for mapping out and better understanding some of the pathways that these cells use to accomplish the tremendous amount of work that they do," Goods says.

Milk composition

The researchers also found links between the composition of cells in breast milk and events such as babies starting to go to daycare, starting formula, or the mother starting to use hormonal birth control.

"There are clearly changes in the composition of breast milk that are related to these lifestyle and health changes, such as infant illness or maternal hormonal birth control," Nyquist says. "These changes in lactation don't necessarily have a positive or negative impact on anyone's health, but they do occur and they may lead us to insights into how mammary epithelial cells are producing milk and the types of components that they may be producing."

The researchers now hope to do larger studies that could help them find stronger links between environmental factors and milk composition, and also discover more about how milk naturally changes over time. This could eventually help scientists devise better infant formulas or create formulas adapted to different stages of infancy. The researchers also hope to find ways to help nursing mothers boost their milk production or slow it down when babies are being weaned.

Other follow-up studies may explore how pumping affects milk composition and breast health, or how to prevent conditions such as mastitis.

Read more at Science Daily

'Ears' for rover Perseverance's exploration of Mars

For two decades, Roger Wiens has built instruments to give humans eyes and a nose on Mars -- and now he's helping add ears as well.

Wiens, a professor of Earth, Atmospheric, and Planetary Sciences in the College of Science at Purdue University, and an expert in Mars robotics technology, led the team that built SuperCam, a device on the Perseverance Mars rover that includes a laser for zapping rocks as well as the microphone that brought the first recordings of Mars to Earth.

"When I was at Los Alamos National Laboratory, I started looking around to see if there were any Department of Energy technologies that we might be able to harness and use for planetary science, and that's where Curiosity's ChemCam, which later evolved into Perseverance's SuperCam, came from," Wiens said.

SuperCam incorporates a technology that uses a pulsed laser beam to pulverize tiny bits of rock samples up to 30 feet away. The instrument collects the light from the brief flash emitted in the process, allowing scientists to analyze rocks that its arm can't reach and to "see" and analyze samples even through Mars dust that coats the rocks.

In incorporating the microphone into SuperCam, Wiens and his collaborators have opened up opportunities for a range of science and research on the Martian surface that was never possible before, including helping analyze rock and recording sounds.

"When we zap these rocks, we can find out more about their hardness and composition by listening to the change in sound as a number of laser shots get fired into the rock in the same spots," Wiens said. "We can hear the helicopter Ingenuity, which is something we didn't expect to be able to hear. We can hear the wind and measure the speed and direction, as well as measure the size and speed of dust devils. We can listen to the rover's own sounds and monitor health and safety the same way you gauge your car's well-being by listening to the motor. Things sound different on Earth because the rover's ears are shaped different from ours and the atmosphere is so different, but we're making recordings and learning things every other day."

Read more at Science Daily

Solar cell keeps working long after sun sets

About 750 million people in the world do not have access to electricity at night. Solar cells provide power during the day, but saving energy for later use requires substantial battery storage.

In Applied Physics Letters, by AIP Publishing, researchers from Stanford University constructed a photovoltaic cell that harvests energy from the environment during the day and night, avoiding the need for batteries altogether. The device makes use of the heat leaking from Earth back into space -- energy that is on the same order of magnitude as incoming solar radiation.

At night, solar cells radiate and lose heat to the sky, reaching temperatures a few degrees below the ambient air. The device under development uses a thermoelectric module to generate voltage and current from the temperature gradient between the cell and the air. This process depends on the thermal design of the system, which includes a hot side and a cold side.

"You want the thermoelectric to have very good contact with both the cold side, which is the solar cell, and the hot side, which is the ambient environment," said author Sid Assawaworrarit. "If you don't have that, you're not going to get much power out of it."

The team demonstrated power generation in their device during the day, when it runs in reverse and contributes additional power to the conventional solar cell, and at night.

The setup is inexpensive and, in principle, could be incorporated within existing solar cells. It is also simple, so construction in remote locations with limited resources is feasible.

"What we managed to do here is build the whole thing from off-the-shelf components, have a very good thermal contact, and the most expensive thing in the whole setup was the thermoelectric itself," said author Zunaid Omair.

Using electricity at night for lighting requires a few watts of power. The current device generates 50 milliwatts per square meter, which means lighting would require about 20 square meters of photovoltaic area.

"None of these components were specifically engineered for this purpose," said author Shanhui Fan. "So, I think there's room for improvement, in the sense that, if one really engineered each of these components for our purpose, I think the performance could be better."

Read more at Science Daily

Sport improves concentration and quality of life

Physically fit primary school pupils feel better and can concentrate better. They are more likely to make it to higher-level secondary grammar schools than children with less sporting abilities. This has been confirmed for the first time in a study by the Department of Sport and Health Sciences at the Technical University of Munich (TUM).

Movement on a regular basis keeps kids healthy and fit for school. The benefits of sports have been demonstrated in numerous studies. Now a research team at the TU Munich has found proof of the correlation between physical fitness, concentration and health-related quality of life for primary school pupils.

The study involved 3285 girls and 3248 boys from Bavaria's Berchtesgadener Land district. The key criteria were physical strength and endurance, the ability to concentrate and health-related quality of life, as determined by the scientists according to internationally standardized test procedures.

Promoting children's motor skills at an early stage is important

The results of the study show: The higher the level of children's physical fitness, the better they can concentrate and the higher their health-related quality of life. While the boys did better on the fitness tests, the girls performed better in terms of concentration and quality of life values.

At the same time, in all tests for physical fitness overweight and obese children had significantly poorer results than underweight children and children with normal body weight. Obese children also had significantly poorer values for health-related quality of life on the whole, physical well-being, self-esteem as well as well-being in friendships and at school.

Sport helps on the way to higher-level secondary grammar schools

Another important result of the study: "Primary school pupils with good physical fitness and a good ability to concentrate are more likely to make it to secondary grammar schools," says Prof. Renate Oberhoffer-Fritz, holder of the TUM Chair of Preventive Pediatrics and Dean of the TUM Department of Sport and Health Sciences.

"This means it's all the more important to encourage motor development in children at an early stage, since this can also have a positive impact on the development of mental fitness," adds Prof. Oberhoffer-Fritz. "Collaboration among parents, schools, communities and athletic clubs is very important when it comes to creating a comprehensive and appropriate range of possibilities."

Dr. Thorsten Schulz, head of the study team at TUM: "Based on the results of the study, since 2019 the Berchtesgadener Land District Administration Office has been giving all first grade pupils in the region a voucher for a one year membership in a sports club. This is a great example for how different stakeholders can work together and help motivate children to be more athletically active."

The data were collected based on internationally recognized and standardized, age-appropriate tests. Thus physical strength and endurance were measured according to the criteria of the FitnessGram guidelines, ability to concentrate was determined using the d2-R test and the health-related quality of life (HRQOL) was measured using the KINDL questionnaire.

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Miniature brain models: Understanding autism

To better understand the causes of autism spectrum disorders (ASD) it is crucial to look at what is happening in the brain during development. The closest we come to observing human brains this early is by using organoids -- miniature models of organs. With their help, scientists at the Institute of Science and Technology Austria (ISTA) discovered how mutations in a high-risk gene of autism disrupt important developmental processes.

Several hundred genes are associated with autism spectrum disorders. Some patients are only mildly affected, while others have severe disabilities. In addition to characteristic symptoms like difficulties in social interaction and communication with other people, as well as repetitive-stereotypic behaviors, patients with mutations of the gene CHD8 oftentimes have intellectual disabilities and macrocephaly -- an unusually large brain. How CHD8 causes these symptoms has long been unclear.

Tiny artificial brains

Since CHD8 mutations affect the brain at a very early stage of its development, it has proven difficult for scientists to get the full picture. Over the past years, many researchers therefore used mice as model organisms to better understand what is going on. "But mice with a CHD8 mutation barely showed the symptoms human patients are showing. The effects in mice are not comparable to humans. We needed some kind of human model," Professor Gaia Novarino explains.

Together with collaborators from the Italian Human Technopole institute, the European Institute of Oncology, and the University of Milan, as well as the Allen Institute for Brain Science, USA, Novarino and her team at ISTA turned to organoids. These simplified miniature versions of organs are made from stem cells, which have the ability to become almost every other type of cell. By creating the right circumstances and giving the proper input at just the right time, the scientists were able to mimic developmental processes to create basic versions of brain tissue the size of lentils. "Organoids are the only way you can study human brain development at such an early phase," says Bárbara Oliveira, postdoc in the Novarino group and one of the authors of the study.

CHD8 mutations disrupt balance of neuron production

In petri dishes the team created brain organoids with and without mutations of the gene CHD8. "After some time, we could see by eye that the mutant organoids were much bigger. That was the first evidence that the model works," her colleague and co-author, PhD student Christoph Dotter, describes. Like patients with a CHD8 mutation, the organoids were showing signs of brain overgrowth.

Getting an overview of all the cell types in the organoids, the team notices something very early on: The mutant organoids started to produce a specific type of neurons, inhibitory neurons, much earlier than the control group. So called excitatory neurons, however, were produced later. Furthermore, the mutant organoids produced much more proliferating cells that later on produce a larger amount of this kind of neurons. Over all, the scientists concluded, this leads to them being significantly bigger than the organoids without CHD8 mutations correlating with patient's macrocephaly.

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Scientists connect the dots between Galilean moon, auroral emissions on Jupiter

On November 8, 2020, NASA's Juno spacecraft flew through an intense beam of electrons traveling from Ganymede, Jupiter's largest moon, to its auroral footprint on the gas giant. Southwest Research Institute scientists used data from Juno's payload to study the particle population traveling along the magnetic field line connecting Ganymede to Jupiter while, at the same time, remotely sensing the associated auroral emissions to unveil the mysterious processes creating the shimmering lights.

"Jupiter's most massive moons each create their own auroras on Jupiter's north and south poles," said Dr. Vincent Hue, lead author of a paper outlining the results of this research. "Each auroral footprint, as we call them, is magnetically connected to their respective moon, kind of like a magnetic leash connected to the moon glowing on Jupiter itself."

Like the Earth, Jupiter experiences auroral light around the polar regions as particles from its massive magnetosphere interact with molecules in the Jovian atmosphere. However, Jupiter's auroras are significantly more intense than Earth's, and unlike Earth, Jupiter's largest moons also create auroral spots. The Juno mission, led by SwRI's Dr. Scott Bolton, is circling Jupiter in a polar orbit and flew through the electron "thread" connecting Ganymede with its associated auroral footprint.

"Prior to Juno, we knew that these emissions can be quite complex, ranging from a single auroral spot to multiple spots, which sometimes trail an auroral curtain that we called the footprint tail," said Dr. Jamey Szalay, a co-author from Princeton University. "Juno, flying extremely close to Jupiter, revealed these auroral spots to be even more complex than previously thought."

Ganymede is the only moon in our solar system that has its own magnetic field. Its mini-magnetosphere interacts with Jupiter's massive magnetosphere, creating waves that accelerate electrons along the gas giant's magnetic field lines, which can be directly measured by Juno.

Two SwRI-led instruments on Juno, the Jovian Auroral Distributions Experiment (JADE) and the Ultraviolet Spectrometer (UVS) provided key data for this study, which was also supported by Juno's magnetic field sensor built at NASA's Goddard Space Flight Center.

"JADE measured the electrons traveling along the magnetic field lines, while UVS imaged the related auroral footprint spot," said SwRI's Dr. Thomas Greathouse, a co-author on this study.

In this way, Juno is both able to measure the electron "rain" and immediately observe the UV light it creates when it crashes into Jupiter. Previous Juno measurements showed that large magnetic perturbations accompanied the electron beams causing the auroral footprint. However, this time, Juno did not observe similar perturbations with the electron beam.

"If our interpretation is correct, this a confirmation of a decade-old theory that we put together to explain the morphology of the auroral footprints," said Dr. Bertrand Bonfond, a co-author of the study from the Liège University in Belgium. The theory suggests that electrons accelerated in both directions create the multi-spot dance of auroral footprints.

Read more at Science Daily

Delicate balance of coral reef processes creates management challenges

An international team of researchers, including several from the University of Hawai'i (UH) at M?noa, has quantified five critical ecological processes on more than 500 coral reefs worldwide to understand how these processes relate to each other, what may distinguish the most functional reefs, and what that means for our management of reef functioning.

Their work, published today in Nature Ecology and Evolution, demonstrates that five key functions performed by fish communities-the removal of algae, predation, biomass production, and the cycling of nitrogen and phosphorus- are inherently interconnected. As such, while the performance of these processes is influenced by the community structure of reef fishes on any given reef, no reef can maximize each of the five processes simultaneously.

Coral reefs are often described as the rainforests of the ocean. They host a high diversity of species and are very productive. Climate change and local threats, such as overfishing, have caused a stark decline in coral reefs worldwide, leaving scientists questioning whether future generations will still encounter healthy, 'functional' coral reefs. But what exactly makes a coral reef 'functional'?

"Imagine a coral reef fish community swirling with small fishes that feed on algae," explained Nina Schiettekatte, the lead author, former doctoral student at the Center for Island Research and Environmental Observatory and postdoctoral fellow at UH M?noa's Hawai'i Institute of Marine Biology (HIMB). "This community will be characterized by high algal consumption and high biomass production, but it will have low phosphorus cycling because these species excrete very little phosphorus."

This means that ecological processes on coral reefs worldwide are in a delicate balance, where it is impossible to maximize all processes. The researchers gained this knowledge by collecting data from individual fishes and combining it with a large dataset on fish communities worldwide.

A detailed look reveals local super heroes

"Throughout this project, we collected thousands of fishes across more than 100 species to gain detailed biological information on how they acquire and use energy and nutrients," explained Jordan Casey, an Assistant Professor at the University of Texas at Austin.

This information can then be projected onto communities to understand how fish communities collectively move biomass and nutrients through the foodweb.

"Our work is novel because it quantifies multiple functions for the first time," Valeriano Parravicini, Professor at EPHE in Perpignan, France stated. "Previously, most researchers have used the biomass of a fish community as a proxy for coral reef functioning but we show that it is critical to look beyond biomass and really disentangle the different components of functioning to understand how reefs work."

Knowing that no reef can excel in all functions, the researchers asked whether there is a certain set of species that is more important than others. Surprisingly, they found that no single species was consistently important across its range, but half of all species were important in at least one location.

"This means that there are no global super-hero fish species for ecosystem functioning," said Sébastien Villéger, researcher at the CNRS in Montpellier, France. "But there are many local super heroes."

A more nuanced management approach

"This work really changes the way we need to think about coral reef conservation," Simon Brandl, an Assistant Professor at the University of Texas at Austin concluded. "Since we cannot maximize all aspects of functioning, we clearly need to develop a more nuanced approach to conserving coral reefs that considers local species, ecosystem dynamics, and stakeholder needs."

Read more at Science Daily

Bees win in survival wars

Like diseases affecting humans, parasites can wage a deadly evolutionary "arms race" against their hosts. But can hosts and parasites upgrade their weapons at the same rate?

This can be a very unequal battle for two reasons. If the parasite is too successful it will wipe out its host, and therefore lose its only means of surviving. At the same time, evolutionary "wars" between hosts and their parasites depend on their rates of evolution; we can think of that as their ability to 'upgrade their weapons'.

Flinders University researchers examined this conundrum by examining a social bee (Exoneura) and its social parasite, another bee (Inquilina).

"These parasitic species spend their entire life cycle within the nest of the host species and have extreme adaptations to social parasitism, they are not able to survive without their hosts," says first author Dr Nahid Shokri-Bousjein in an article in Ecology and Evolution.

The ability of species to adapt to existential challenges depends on their ability to 'discover' new strategies via random mutations. The more individuals in a species, the greater the likelihood that a favorable mutation will arise amongst one of them, and that means that species with larger populations should generally win any "wars" against their enemies. So what happens when species and their parasites or pathogens have very different population sizes?

"We can see this problem play out with COVID-19. The virus has a much bigger population size than its host (us!), so its ability to evolve around our defenses is great," says Dr Shokri-Bousjein. "We see this in terms of new COVID variants emerging and then spreading."

But what happens when the pathogen has very small population sizes? "In our previous studies, we found that the population sizes of the parasite species are an order of magnitude lower than their host. Surprisingly, our analyses of molecular data showed that rates of evolution were similar between host and parasite."

Flinders University Associate Professor Mike Schwarz says that "evolutionary wars between species and their enemies may be much more complex than we have thought. Large population sizes might allow more strategies to arise, but maybe the critical issue is how effective those strategies are. Species like these bee social parasites are on the very edge of survival: they might tell us something about how you can survive when your very existence is under threat.

Read more at Science Daily

Disbelief in human evolution linked to greater prejudice and racism

A disbelief in human evolution was associated with higher levels of prejudice, racist attitudes and support of discriminatory behavior against Blacks, immigrants and the LGBTQ community in the U.S., according to University of Massachusetts Amherst research published in the Journal of Personality and Social Psychology.

Similarly, across the globe -- in 19 Eastern European countries, 25 Muslim countries and in Israel -- low belief in evolution was linked to higher biases within a person's group, prejudicial attitudes toward people in different groups and less support for conflict resolution.

The findings supported the hypothesis of lead author Stylianos Syropoulos, a Ph.D. candidate in the War and Peace Labof senior author Bernhard Leidner, associate professor of social psychology. They collaborated with co-first author Uri Lifshin at Reichman University in Israel and co-authors Jeff Greenberg and Dylan Horner at the University of Arizona in Tucson. The researchers theorized that belief in evolution would tend to increase people's identification with all humanity, due to the common ancestry, and would lead to less prejudicial attitudes.

"People who perceive themselves as more similar to animals are also people who tend to have more pro-social or positive attitudes toward outgroup members or people from stigmatized and marginalized backgrounds," Syropoulos explains. "In this investigation, we were interested in examining whether belief in evolution would also act in a similar way, because it would reinforce this belief that we are more similar to animals."

In eight studies involving different areas of the world, the researchers analyzed data from the American General Social Survey (GSS), the Pew Research Center and three online crowdsourced samples. In testing their hypothesis about the associations of different levels of belief in evolution, they accounted for education, political ideology, religiosity, cultural identity and scientific knowledge.

"We found the same results each time, which is basically that believing in evolution relates to less prejudice, regardless of the group you're in, and controlling for all of these alternative explanations," Syropoulos says.

For example, religious beliefs, like political ideology, were measured separately from a belief or disbelief in evolution, the researchers note. "Regardless of whether one considers religion an important part of their life, belief in evolution relates to less prejudice independently from belief, or lack thereof, in God or any particular religion," Syropoulos says.

Leidner adds, "This whole effect and pattern seems to be present in all major political systems. It's very much a human phenomenon, no matter where you are in the world."

The researchers note that Darwin's 19th century theory of evolution has been cited to perpetrate racism, prejudice and homophobia, in part through the phrase, "survival of the fittest," used to describe the process of natural selection.

"There have been theoretical accounts that predict the opposite of what we found, so it was exciting for us to show that this actually is not the case, that the opposite is true and that belief in evolution seems to have pretty positive effects," Leidner says.

The U.S.-based study involved data from 1993, 1994, 2000, 2006, 2008, 2010, 2012, 2014, 2016 and 2018 -- the years the GSS surveyed Americans about their beliefs in evolution, as well as measures of attitudes toward immigrants, Blacks, affirmative action, LGBTQ people and other social matters.

The data analysis showed unfailingly "that the disbelief in human evolution is the driving factor and most consistent predictor of prejudice in comparison to other relevant constructs," the paper states.

In the Israel-based study, people with a higher belief in evolution were more likely to support peace among Palestinians, Arabs and Jews. In the study involving countries in the Islamic world, belief in evolution was associated with less prejudice toward Christians and Jews. And in the study based in Eastern Europe, where Orthodox Christians are the majority, a belief in evolution was linked with less prejudice toward gypsies, Jews and Muslims.

Syropoulos posits that a belief in evolution may expand people's "moral circle," leading to a sense that "we have more in common than things that are different."

The findings also suggest that "teaching evolution seems to have side effects that might make for a better or more harmonious society," Leidner adds.

Read more at Science Daily

Solar hydrogen: Better photoelectrodes through flash heating

Solar energy can directly drive electrochemical reactions at the surface of photoelectrodes. Photoelectrodes consist of semiconducting thin films on transparent conductive-glass substrates that convert light into electricity. Most photoelectrochemical studies have focused on water splitting, a thermodynamically uphill reaction that could offer an attractive pathway for the long-term capture and storage of solar energy by producing 'green' hydrogen.

Metal-oxide thin film photoelectrodes are particularly promising for these diverse functions. They comprise abundant elements, potentially offering infinite tunability to achieve the desired properties -- at potentially low costs.

Made from plasma

At the HZB Institute for Solar Fuels, several teams focus on developing such photoelectrodes. The usual method to produce them is pulsed laser deposition: an intense laser pulse hits a target containing the material and ablates it into a highly energetic plasma deposited on a substrate.

Quality needs heat

Further steps are needed to improve the quality of the deposited thin film. In particular thermal processing of the metal-oxide thin-film reduces defects and imperfections. However, this creates a dilemma: Reducing atomic defects concentration and improvements in crystalline order of the metal-oxide thin films would require thermal processing temperatures between 850 and 1000 degrees Celsius -- but the problem is that the glass substrate melts at 550 degrees Celsius.

Flash-heating the thin film

Dr. Ronen Gottesman from the HZB Institute for Solar Fuels has now solved this problem: After deposition, using high-powered lamps, he flash-heats the metal-oxide thin film. This heats it up to 850 degrees Celsius without melting the underlying glass substrate.

"The heat efficiently reduces structural defects, trap states, grain boundaries, and phase impurities, which would become more challenging to mitigate with an increasing number of elements in the metal-oxides. Therefore, new innovative synthesis approaches are essential. We have now demonstrated this on photoelectrodes made of Ta2O5, TiO2, and WO3, which we heated to 850 °C without damaging the substrates," says Gottesman.

Record performance for α-SnWO4

The new method was also successful with a photoelectrode material that is considered a very good candidate for solar water splitting: α-SnWO4. Conventional furnace heating leaves behind phase impurities. Rapid thermal processing (RTP) heating improved crystallinity, electronic properties, and performance, leading to a new record performance of 1 mA/cm2 for this material, higher by 25% than the previous record.

Read more at Science Daily

Using gene scissors to specifically eliminate individual cell types

With the help of the CRISPR/Cas molecular scissors, genetic information in a plant can be modified to make the latter more robust to pests, diseases, or extreme climatic conditions. Researchers of Karlsruhe Institute of Technology (KIT) have now developed this method further to eliminate the complete DNA of specific cell types and, thus, prevent their formation during plant development. This will also help scientists better understand development mechanisms in plants. The findings are presented in Nature Communications.

By means of molecular scissors, the DNA -- the carrier of genetic information -- can be modified in plants. So far, the CRISPR/Cas method co-developed in plants by Professor Holger Puchta, molecular biologist at KIT's Botanical Institute has already been used to specifically insert, exchange or combine genes. The goal is to increase the plant's resistance to diseases and environmental impacts. CRISPR (stands for Clustered Regularly Interspaced Short Palindromic Repeats)/Cas are molecular scissors that can specifically recognize and cut DNA sequences. "We have studied molecular scissors for plant use for 30 years now. In the beginning, we applied them to modify individual genes. Two years ago, we were the first worldwide to restructure complete chromosomes," Puchta says. For his research, the pioneer of genome editing twice received the Advanced Grant of the European Research Council (ERC). "We were able to optimize this method. With CRISPR-Kill, we have reached now an entirely new level of development: We can eliminate certain plant cell types and prevent the formation of specific plant organs."

Eliminating Secondary Roots and Petals with CRISPR-Kill

The experiments carried out by the scientists concentrated on secondary roots and petals of the model plant thale cress (Arabidopsis thaliana). "These are classical examples in biology. Here, we know the genetic program and the cell types that are important for the formation of these plant organs," the molecular biologist explains. After the elimination of these cells, CRISPR-Kill plants no longer formed any petals or secondary roots, whereas the control plants exhibited normal growth.

Contrary to other methods that eliminate cells with cytotoxins or laser radiation, CRISPR-Kill induces multiple cuts in the genome. A genome consists of a certain number of chromosomes, on which the individual genes are arranged in fixed order. "So far, CRISPR/Cas has aimed for exactly one location and has cut once or twice to modify a gene or chromosome," Puchta says. "Now, we have reprogrammed our molecular scissors. They no longer address the genomic DNA only once, but aim in the respective cell type for a sequence that is encountered often in the genome and that is essential for the survival of the cell. In this way, many cuts are induced at the same time -- too many for the cell to repair them. The cell will die."

Read more at Science Daily

People around the world like the same kinds of smell

What smells we like or dislike is primarily determined by the structure of the particular odour molecule. A collaborative study involving researchers from Karolinska Institutet, Sweden, and the University of Oxford, UK, shows that people share odour preferences regardless of cultural background. The study is published in the journal Current Biology.

"We wanted to examine if people around the world have the same smell perception and like the same types of odour, or whether this is something that is culturally learned," says Artin Arshamian, researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "Traditionally it has been seen as cultural, but we can show that culture has very little to do with it."

The present study shows that the structure of the odour molecule determines whether a smell is considered pleasant or not. The researchers found that certain smells were liked more than others regardless of the cultural affiliation of participants.

"Cultures around the world rank different odours in a similar way no matter where they come from, but odour preferences have a personal -- although not cultural -- component," says Dr Arshamian.

Studied indigenous populations

The study was made possible through an international network of researchers that collaborated in a unique combination of experimental methods and field studies. The network comprised researchers from Karolinska Institutet, Lund University and Stockholm University (Sweden), University of Oxford and University College London (UK), Arizona State University, Monell Chemical Senses Center and the University of Pennsylvania (USA), Universidad San Francisco de Quito (Ecuador), University of Melbourne (Australia) and National Autonomous University of Mexico.

Many of the researchers are field workers working with indigenous populations. For this present study, the researchers selected nine communities representing different lifestyles: four hunter-gatherer groups and five groups with different forms of farming and fishing. Some of these groups have very little contact with Western foodstuffs or household articles.

Disparate odiferous environments

"Since these groups live in such disparate odiferous environments, like rainforest, coast, mountain and city, we capture many different types of 'odour experiences'," says Dr Arshamian.

The study included a total of 235 individuals, who were asked to rank smells on a scale of pleasant to unpleasant. The results show variation between individuals within each group, but global correspondence on which odours are pleasant and unpleasant. The researchers show that the variation is largely explained by molecular structure (41 per cent) and by personal preference (54 per cent).

"Personal preference can be due to learning but could also be a result of our genetic makeup," says Dr Arshamian.

Vanilla was considered most pleasant

The odours the participants were asked to rank included vanilla, which smelled best then followed by ethyl butyrate, which smells like peaches. The smell that most participants considered the least pleasant was isovaleric acid, which can be found in many foods, such as cheese, soy milk and apple juice, but also in foot sweat.

According to Dr Arshamian, a possible reason why people consider some smells more pleasant than others regardless of culture is that such odours increased the chances of survival during human evolution.

"Now we know that there's universal odour perception that is driven by molecular structure and that explains why we like or dislike a certain smell," Dr Arshamian continues. "The next step is to study why this is so by linking this knowledge to what happens in the brain when we smell a particular odour."

Read more at Science Daily

Researchers identify neuronal mechanisms that control food cravings during pregnancy

Many people have felt the sudden and uncontrollable urge to eat a certain food. These urges -- known as cravings -- are very common, mostly during pregnancy. During this time, the mother's body undergoes a series of physiological and behavioural changes to create a favourable environment for the embryo's development. However, the frequent consumption of tasty and high calorie foods -- derived from the cravings -- contributes to weight gain and obesity in pregnancy, which can have negative effects on the baby's health.

"There are many myths and popular beliefs regarding these cravings, although the neuronal mechanisms that cause them are not widely known," notes March Claret, lecturer at the Faculty of Medicine and Health Sciences of the University of Barcelona and head of the IDIBAPS Neuronal Control of Metabolism Group. Claret leads, together with the researcher Roberta Haddad-Tóvolli, a study published in the journal Nature Metabolism that provides new evidence on the alterations of the neuronal activity that drive cravings in an animal model.

Dopamine and compulsive eating behaviour

According to the results, during pregnancy, the brain of female mice undergoes changes in the functional connections of the brain reward circuits, as well as the taste and sensorimotor centers. Moreover, just like pregnant women, female mice are more sensitive to sweet food, and they develop binge-eating behaviours towards high calorie foods. "The alteration of these structures made us explore the mesolimbic pathway, one of the signal transmission pathways of dopaminergic neurons. Dopamine is a key neurotransmitter in motivational behaviours," notes Claret, member of the Department of Medicine of the UB and the Diabetes and Associated Metabolic Diseases Networking Biomedical Research Centre (CIBERDEM).

The team observed the levels of dopamine -- and the activity of its receptor, D2R -- to increase in the nucleus accumbens, a brain region involved in the reward circuit. "This finding suggests that the pregnancy induces a full reorganization of the mesolimbic neural circuits through the D2R neurons," notes Haddad-Tóvolli. "These neuronal cells -- and their alteration -- would be responsible for the cravings, since food anxiety, typical during pregnancy, disappeared after blocking their activity."

The team led by Claret and Haddad-Tóvolli showed that persistent cravings have consequences for the offspring. They affect the metabolism and development of neural circuits that regulate food intake, which leads to weight gain, anxiety and eating disorders. "These results are shocking, since many of the studies are focused on the analysis of how the mother's permanent habits -- such as obesity, malnutrition, or chronic stress -- affect the health of the baby. However, this study indicates that short but recurrent behaviours, such as cravings, are enough to increase the psychological and metabolic vulnerability of the offspring," concludes Claret.

The conclusions of the study could contribute to the improvement of nutritional guidelines for pregnant women in order to ensure a proper prenatal nutrition and prevent the development of diseases. Among the participants in the study were Guadalupe Soria and Emma Muñoz-Moreno (IDIBAPS), Analía Bortolozzi (IIBB-CSIC-IDIBAPS) and Emmanuel Valjent (INSERM and University of Montpelier).

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Researchers discover source of super-fast electron 'rain'

UCLA scientists have discovered a new source of super-fast, energetic electrons raining down on Earth, a phenomenon that contributes to the colorful aurora borealis but also poses hazards to satellites, spacecraft and astronauts.

The researchers observed unexpected, rapid "electron precipitation" from low-Earth orbit using the ELFIN mission, a pair of tiny satellites built and operated on the UCLA campus by undergraduate and graduate students guided by a small team of staff mentors.

By combining the ELFIN data with more distant observations from NASA's THEMIS spacecraft, the scientists determined that the sudden downpour was caused by whistler waves, a type of electromagnetic wave that ripples through plasma in space and affects electrons in the Earth's magnetosphere, causing them to "spill over" into the atmosphere.

Their findings, published March 25 in the journal Nature Communications, demonstrate that whistler waves are responsible for far more electron rain than current theories and space weather models predict.

"ELFIN is the first satellite to measure these super-fast electrons," said Xiaojia Zhang, lead author and a researcher in UCLA's department of Earth, planetary and space sciences. "The mission is yielding new insights due to its unique vantage point in the chain of events that produces them."

Central to that chain of events is the near-Earth space environment, which is filled with charged particles orbiting in giant rings around the planet, called Van Allen radiation belts. Electrons in these belts travel in Slinky-like spirals that literally bounce between the Earth's north and south poles. Under certain conditions, whistler waves are generated within the radiation belts, energizing and speeding up the electrons. This effectively stretches out the electrons' travel path so much that they fall out of the belts and precipitate into the atmosphere, creating the electron rain.

One can imagine the Van Allen belts as a large reservoir filled with water -- or, in this case, electrons, said Vassilis Angelopolous, a UCLA professor of space physics and ELFIN's principal investigator. As the reservoir fills, water periodically spirals down into a relief drain to keep the basin from overflowing. But when large waves occur in the reservoir, the sloshing water spills over the edge, faster and in greater volume than the relief drainage. ELFIN, which is downstream of both flows, is able to properly measure the contributions from each.

The low-altitude electron rain measurements by ELFIN, combined with the THEMIS observations of whistler waves in space and sophisticated computer modeling, allowed the team to understand in detail the process by which the waves cause rapid torrents of electrons to flow into the atmosphere.

The findings are particularly important because current theories and space weather models, while accounting for other sources of electrons entering the atmosphere, do not predict this extra whistler wave-induced electron flow, which can affect Earth's atmospheric chemistry, pose risks to spacecraft and damage low-orbiting satellites.

The researchers further showed that this type of radiation-belt electron loss to the atmosphere can increase significantly during geomagnetic storms, disturbances caused by enhanced solar activity that can affect near-Earth space and Earth's magnetic environment.

"Although space is commonly thought to be separate from our upper atmosphere, the two are inextricably linked," Angelopoulos said. "Understanding how they're linked can benefit satellites and astronauts passing through the region, which are increasingly important for commerce, telecommunications and space tourism."

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Mounds of ice in craters give new insight into Mars’ past climate

Newly discovered deposits of layered ice in craters scattered around Mars' southern hemisphere provide insights into how the planet's orientation controlled the planet's climate over the past 4 million years, according to a new study. The findings help scientists understand what controlled Mars' past climate, which is essential for predicting when the planet could have been habitable.

The study was published in the AGU journal Geophysical Research Letters, which publishes short-format, high-impact research with implications spanning the Earth and space sciences.

Ice deposits on Mars reflect a combination of temperature, hydrology and planetary dynamics, as they do on Earth. The planet's tilt and orbit impact temperature and sunlight on the surface, which contribute to climate. Thicker, more pure ice layers generally reflect cold periods with more ice accumulation, while thin, dusty layers were likely warmer and less able to build up ice.

The new study matches these ice layers to the tilt of Mars' axis and its orbital precession, or how the planet's elliptical orbit rotates around the sun over time, with unprecedented resolution and confidence.

The findings give scientists insight into how Mars' climate has changed over time. While the study is limited to the recent past, establishing these climate-orbit relationships helps scientists understand Martian climate deeper in the past, which could help pinpoint periods of potential habitability.

"It was unexpected how cleanly those patterns matched to the orbital cycles," said lead study author Michael Sori, a planetary scientist at Purdue University. "It was just such a perfect match, as good as you can ask for."

From caps to craters

Previously, Martian climate scientists have focused on polar ice caps, which span hundreds of kilometers. But these deposits are old and may have lost ice over time, losing fine details that are necessary to confidently establish connections between the planet's orientation and motion and its climate.

Sori and his colleagues turned to ice mounds in craters, just tens of kilometers wide but much fresher and potentially less complicated. After scouring much of the southern hemisphere, they pinpointed Burroughs crater, 74 kilometers wide, that has "exceptionally well-preserved" layers visible from NASA HiRISE imagery, Sori said.

The researchers analyzed the layers' thicknesses and shapes and found they had strikingly similar patterns to two important Martian orbital dynamics, the tilt of Mars' axis and orbital precession, over the last 4 to 5 million years.

The findings improve on previous research, which used Mars' polar ice records of climate to establish tentative connections to orbit. But those records were too "noisy," or complicated, to confidently connect the two. Younger, cleaner crater ice preserves less complicated climate records, which the researchers used to match climate changes to orbital precession and tilt with a high level of precision.

Mars as a natural lab

Discerning the connections between orbital cycles and climate is important for understanding both Martian history and complex climate dynamics on Earth. "Mars is a natural laboratory for studying orbital controls on climate," Sori said, because many of the complicating factors that exist on Earth -- biology, tectonics -- are negligible on Mars. The whole planet, in essence, isolates the variable for scientists.

"If we're ever going to understand climate, we need to go to places that don't have these interfering factors," said Isaac Smith, a planetary scientist at the Planetary Science Institute and York University who was not involved in the study. In that sense, "Mars is a pristine planet. And there are a lot of potential applications here. Mars has a lot more in common with Pluto and Triton than you think."

Not all smaller ice deposits have clean, exposed layers at their surface. Some might be hidden inside the mounds. Eventually, Sori said, the goal is to sample ice cores like scientists do on Earth, but Mars rovers don't have that capability yet. Instead, scientists can use ground-penetrating radar data to "peer inside" the ice and check for layers, making sure visible layers extend throughout the deposit. It's a necessary quality-control step in the present study, and the method may help future explorations of Martian ice without layers visible at the surface.

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