Neptune-like exoplanets can be cloudy or clear

The study of "exoplanets," the sci-fi-sounding name for all planets in the cosmos beyond our own solar system, is a pretty new field. Mainly, exoplanet researchers like those in the ExoLab at the University of Kansas use data from space-borne telescopes such as the Hubble Space Telescope and Webb Space Telescope. Whenever news headlines offer findings of "Earth-like" planets or planets with the potential to support humanity, they're talking about exoplanets within our own Milky Way.

Jonathan Brande, a doctoral candidate in the ExoLab at the University of Kansas, has just published findings in the open-access scientific journal The Astrophysical Journal Letters showing new atmospheric detail in a set of 15 exoplanets similar to Neptune. While none could support humanity, a better understanding of their behavior might help us to understand why we don't have a small Neptune, while most solar systems seem to feature a planet of this class.

"Over the past several years at KU, my focus has been studying the atmospheres of exoplanets through a technique known as transmission spectroscopy," Brande said. "When a planet transits, meaning it moves between our line of sight and the star it orbits, light from the star passes through the planet's atmosphere, getting absorbed by the various gases present. By capturing a spectrum of the star -- passing the light through an instrument called a spectrograph, akin to passing it through a prism -- we observe a rainbow, measuring the brightness of different constituent colors. Varied areas of brightness or dimness in the spectrum reveal the gases absorbing light in the planet's atmosphere."

With this methodology, several years ago Brande published a paper concerning the "warm Neptune" exoplanet TOI-674 b, where he presented observations indicating the presence of water vapor in its atmosphere. These observations were part of a broader program led by Brande's adviser, Ian Crossfield, associate professor of physics & astronomy at KU, to observe atmospheres of Neptune-sized exoplanets.

"We want to comprehend the behaviors of these planets, given that those slightly larger than Earth and smaller than Neptune are the most common in the galaxy," Brande said.

This recent ApJL paper summarizes observations from that program, incorporating data from additional observations to address why some planets appear cloudy while others are clear.

"The goal is to explore the physical explanations behind the distinct appearances of these planets," Brande said.

Brande and his co-authors took special note of regions where exoplanets tend to form clouds or hazes high up in their atmosphere. When such atmospheric aerosols are present, the KU researcher said hazes can block the light filtering through the atmosphere.

"If a planet has a cloud right above the surface with hundreds of kilometers of clear air above it, starlight can easily pass through the clear air and be absorbed only by the specific gases in that part of the atmosphere," Brande said. "However, if the cloud is positioned very high, clouds are generally opaque across the electromagnetic spectrum. While hazes have spectral features, for our work, where we focus on a relatively narrow range with Hubble, they also produce mostly flat spectra."

According to Brande, when these aerosols are present high in the atmosphere, there's no clear path for light to filter through.

"With Hubble, the single gas we're most sensitive to is water vapor," he said. "If we observe water vapor in a planet's atmosphere, that's a good indication that there are no clouds high enough to block its absorption. Conversely, if water vapor is not observed and only a flat spectrum is seen, despite knowing that the planet should have an extended atmosphere, it suggests the likely presence of clouds or hazes at higher altitudes."

Brande led the work of an international team of astronomers on the paper, including Crossfield at KU and collaborators from the Max Planck Institute in Heidelberg, Germany, a cohort led by Laura Kreidberg, and investigators at the University of Texas, Austin, led by Caroline Morley.

Brande and his co-authors approached their analysis differently than previous efforts by focusing on determining the physical parameters of the small-Neptune atmospheres. In contrast, previous analyses often involved fitting a single model spectrum to observations.

"Typically, researchers would take an atmospheric model with pre-computed water content, scale and shift it to match observed planets in their sample," Brande said. "This approach indicates whether the spectrum is clear or cloudy but provides no information about the amount of water vapor or the location of clouds in the atmosphere."

Instead, Brande employed a technique known as "atmospheric retrieval."

"This involved modeling the atmosphere across various planet parameters such as water vapor quantity and cloud location, iterating through hundreds and thousands of simulations to find the best fit configuration," he said. "Our retrievals gave us a best-fit model spectrum for each planet, from which we calculated how cloudy or clear the planet appeared to be. Then, we compared those measured clarities to a separate suite of models by Caroline Morley, which let us see that our results are in line with expectations for similar planets. In examining cloud and haze behavior, our models indicated that clouds were a better fit than hazes. The sedimentation efficiency parameter, reflecting cloud compactness, suggested observed planets had relatively low sedimentation efficiencies, resulting in fluffy clouds. These clouds, made up of particles like water droplets, remained lofted in the atmosphere due to their low settling tendency."

Brande's findings provide insights into the behavior of these planetary atmospheres and caused "substantial interest" when he presented them at a recent meeting of the American Astronomical Society.

Read more at Science Daily

Why are people climate change deniers?

Do climate change deniers bend the facts to avoid having to modify their environmentally harmful behavior? Researchers from the University of Bonn and the Institute of Labor Economics (IZA) ran an online experiment involving 4,000 US adults, and found no evidence to support this idea. The authors of the study were themselves surprised by the results. Whether they are good or bad news for the fight against global heating remains to be seen. The study is being published in the journal Nature Climate Change.

A surprisingly large number of people still downplay the impact of climate change or deny that it is primarily a product of human activity.

But why? One hypothesis is that these misconceptions are rooted in a specific form of self-deception, namely that people simply find it easier to live with their own climate failings if they do not believe that things will actually get all that bad.

"We call this thought process 'motivated reasoning,'" says Professor Florian Zimmermann, an economist at the University of Bonn and Research Director at IZA.

Motivated reasoning helps us to justify our behavior. For instance, someone who flies off on holiday several times a year can give themselves the excuse that the plane would still be taking off without them, or that just one flight will not make any difference, or -- more to the point -- that nobody has proven the existence of human-made climate change anyway.

All these patterns of argument are examples of motivated reasoning.

Bending the facts until it allows us to maintain a positive image of ourselves while maintaining our harmful behavior.

Self-deception to preserve a positive self-image

But what role does this form of self-deception play in how people think about climate change?

Previously, there had been little scientific evidence produced to answer the question.

The latest study has now closed this knowledge gap -- and has thrown up some unexpected results.

Zimmermann and his colleague Lasse Stötzer ran a series of online experiments, using a representative sample of 4,000 US adults.

At the center of the experiments was a donation worth $20. Participants were allocated at random to one of two groups.

The members of the first group were able to split the $20 between two organizations, both of which were committed to combating climate change.

By contrast, those in the second group could decide to keep the $20 for themselves instead of giving it away and would then actually receive the money at the end.

"Anyone keeping hold of the donation needs to justify it to themselves," says Zimmermann, who is also a member of the ECONtribute Cluster of Excellence, the Collaborative Research Center Transregio 224 and the Transdisciplinary Research Area "Individuals & Societies" at the University of Bonn.

"One way to do that is to deny the existence of climate change."

As it happened, nearly half of those in the second group decided to hold on to the money.

The researchers now wanted to know whether these individuals would justify their decision retrospectively by repudiating climate change.

The two groups had been put together at random. Without "motivated reasoning," therefore, they should essentially share a similar attitude to human-made global heating.

If those who kept the money for themselves justified their actions through self-deception, however, then their group should exhibit greater doubt over climate change.

"Yet we didn't see any sign of that effect," Zimmermann reveals.

Climate change denial: a hallmark of one's identity?

This finding was also borne out in two further experiments. "In other words, our study didn't give us any indications that the widespread misconceptions regarding climate change are due to this kind of self-deception," says Zimmermann, summing up his work.

On the face of it, this is good news for policymakers, because the results could mean that it is indeed possible to correct climate change misconceptions, simply by providing comprehensive information.

If people are bending reality, by contrast, then this approach is very much a non-starter.

Zimmermann advises to be cautious, however: "Our data does reveal some indications of a variant of motivated reasoning, specifically that denying the existence of human-made global heating forms part of the political identity of certain groups of people." Put another way, some people may to an extent define themselves by the very fact that they do not believe in climate change.

As far as they are concerned, this way of thinking is an important trait that sets them apart from other political groups, and thus they are likely to simply not care what researchers have to say on the topic.

Read more at Science Daily

Gene-editing offers hope for people with hereditary disorder

A group of patients with a hereditary disorder have had their lives transformed by a single treatment of a breakthrough gene-editing therapy, according to the lead researcher.

The patients from New Zealand, the Netherlands and the UK have hereditary angioedema, a genetic disorder characterised by severe, painful and unpredictable swelling attacks.

These interfere with daily life and can affect airways and prove fatal.

Now researchers from the University of Auckland, Amsterdam University Medical Center and Cambridge University Hospitals have successfully treated more than ten patients with the CRISPR/Cas9 therapy, with interim results just published in a leading journal.

"It looks as if the single-dose treatment will provide a permanent cure for my hereditary angioedema patients' very disabling symptoms," says principal investigator Dr Hilary Longhurst, who is both a clinical immunologist at Auckland Hospital Te Toku Tumai and an honorary associate professor at the University of Auckland.

"Plus, of course, there is huge potential for development of similar CRISPR/Cas9 treatments for other genetic disorders."

Globally, it is estimated one in 50,000 people have hereditary angioedema, however, because it is rare, it is often not correctly diagnosed.

In the phase one study, there were no serious or lasting side-effects from the single infusion, which took place over two to four hours under clinical supervision from late 2021 and onwards.

The investigational therapy, called NTLA-2002, utilises in vivo CRISPR/Cas9 technology to target the KLKB1 gene, which is responsible for producing plasma prekallikrein.

By editing this gene, the therapy reduces the levels of total plasma kallikrein, effectively preventing angioedema (swelling) attacks.

The trial, published in the New England Journal of Medicine, demonstrated dose-dependent reduction in total plasma kallikrein protein with reductions of up to 95 percent achieved.

A mean reduction of 95 percent in angioedema attacks was observed across all patients through to the latest follow-up.

The patients from the initial study will be followed up for a further 15 years to continue to assess long-term safety and efficacy.

A larger and more robust, double-blinded, placebo-controlled phase two trial is under way and a Phase 3 trial is planned to start in the second half of 2024.

Dr Danny Cohn, from the Department of Vascular Medicine at the Amsterdam University Medical Center says these promising results are a step forward for this group of patients.

"We've never been closer to the ultimate treatment goal of normalising hereditary angioedema patients' lives and offering total control of the disease," says Dr Cohn.

Dr Padmalal Gurugama, consultant in clinical immunology and allergy at Cambridge University Hospitals, UK says the gene editing therapy has the potential to significantly improve patients' lives.

"Hereditary angioedema can cause patients severe swellings and intense pain which can be life-threatening as well as restricting normal activities, such as going to work or school.

"Because it is often misdiagnosed, many patients undergo unnecessary treatments and invasive procedures."

The therapy affects only the patient and is not passed onto their children, who still have an even chance of inheriting the disorder.

The studies have been funded by US company Intellia Therapeutics, which chose New Zealand to lead the research as, at that time -- late 2021, it had relatively fewer Covid-19 cases than other countries.

So far, the only approved CRISPR therapy, CASGEVY, is for sickle cell disease and beta thalassemia.

However, CASGEVY is an ex vivo CRISPR therapy, where the cells are taken from the patient and edited outside of the body and then reinfused, whereas NTLA-2002 is an in vivo CRISPR therapy, where the targeted gene editing occurs directly within the body.

Read more at Science Daily

The hottest catalog of the year: Comprehensive list of slow-building solar flares

Solar flares occur when magnetic energy builds up in the Sun's atmosphere and is released as electromagnetic radiation. Lasting anywhere from a few minutes to a few hours, flares usually reach temperatures around 10 million degrees Kelvin. Because of their intense electromagnetic energy, solar flares can cause disruptions in radio communications, Earth-orbiting satellites and even result in blackouts.

Although flares have been classified based on the amount of energy they emit at their peak, there has not been significant study into differentiating flares based on the speed of energy build-up since slow-building flares were first discovered in the 1980s.

In a new paper in Solar Physics, a team, led by UC San Diego astrophysics graduate student Aravind Bharathi Valluvan, has shown that there is a significant amount of slower-type flares worthy of further investigation.

The width-to-decay ratio of a flare is the time it takes to reach maximum intensity to the time it takes to dissipate its energy.

Most commonly, flares spend more time dissipating than rising.

In a 5-minute flare, it may take 1 minute to rise and 4 minutes to dissipate for a ratio of 1:4. In slow-building flares, that ratio may be 1:1, with 2.5 minutes to rise and 2.5 minutes to dissipate.

Valluvan was a student at the Indian Institute of Technology Bombay (IITB) when this work was conducted.

Exploiting the increased capabilities of the Chandrayaan-2 solar orbiter, IITB researchers used the first three years of observed data to catalog nearly 1400 slow-rising flares -- a dramatic increase over the roughly 100 that had been previously observed over the past four decades.

It was thought that solar flares were like the snap of a whip -- quickly injecting energy before slowly dissipating.

Now seeing slow-building flares in such high quantities may change that thinking.

Read more at Science Daily

Death toll shows extreme air pollution events a growing urban threat

New Curtin University-led research has estimated that 1454 avoidable deaths (one person every five days) occurred in Australian capital cities in the past 20 years because of fine particle air pollution from extreme events such as bushfires and dust storms, wood-heater smoke or industrial accidents.

The study also found that nearly one-third of deaths from extreme air pollution exposure days could be prevented if pollution events were reduced by as little as 5 per cent.

Lead researcher Dr Lucas Hertzog from Curtin's World Health Organisation Collaborating Centre for Climate Change and Health Impact Assessment said the findings highlighted the urgent need for effective strategies to manage air quality, particularly during extreme weather events like bushfires and dust storms, which are becoming more common due to climate change.

"Using data from 2001 to 2020 from air pollution monitoring sites, combined with a range of satellite and land use-related data, we modelled the exposure to exceptional levels of particulate matter air pollution (PM2.5) for each extreme pollution exposure day," Dr Hertzog said.

"Despite relatively low daily PM2.5 levels generally (compared to global averages), Australian cities experience days with extreme pollution levels where PM2.5 concentrations exceed the WHO Air Quality Guideline standard.

"Sydney and Melbourne reported the highest number of deaths attributable to extreme air pollution events, with 541 and 438 deaths respectively, followed by Brisbane and Perth with 171 and 132 deaths."

"Adelaide and Hobart were the cities that showed, across the 20-year period, fewer days exceeding WHO air quality exposure recommendations, with Adelaide recording only five days and Hobart 11 days above the threshold.

"Darwin, despite its relatively low number of deaths due to PM2.5 exposure events, experienced a high number of days exceeding WHO recommendations, ten times more than cities like Melbourne."

Dr Hertzog said the findings show how extreme air pollution events could seriously affect health in urban areas, and understanding this link was crucial, as climate change may increase the frequency and intensity of such pollution events.

"Diseases associated with particulate matter air pollution include asthma and COPD (chronic obstructive pulmonary disease) as well as cardiovascular disorders," Dr Hertzog said.

"Our study's insights can aid in protecting public health by helping to inform policy development and actions to reduce impacts from extreme air pollution events.

"While responding to bushfires and dust storms is an increasingly challenging task, authorities have a crucial role in land use management. They also regulate energy policy and control wood heater regulations. Additional strategies to reduce emissions from industrial accidents or road transport-related smog events could enhance the control of sources of air pollution and improve well-being.

"It is also possible to reduce the burden of mortality by improving public health warnings and increasing community awareness of smoke avoidance behaviours."

Read more at Science Daily

'Genomic time machine' reveals secrets of our DNA

The human genome, an intricate tapestry of genetic information for life, has proven to be a treasure trove of strange features. Among them are segments of DNA that can "jump around" and move within the genome, known as "transposable elements" (TEs).

As they change their position within the genome, TEs can potentially cause mutations and alter the cell's genetic profile, but also are master orchestrators of our genome's organization and expression.

For example, TEs contribute to regulatory elements, transcription factor binding sites, and the creation of chimeric transcripts -- genetic sequences created when segments from two different genes or parts of the genome join together to form a new, hybrid RNA molecule.

Matching their functional importance, TEs have been recognized to account for half of the human DNA.

However, as they move and age, TEs pick up changes that mask their original form.

Over time, TEs "degenerate" and become less recognizable, making it difficult for scientists to identify and track them in our genetic blueprint.

In a new study, researchers in the group of Didier Trono at EPFL have found a way to improve the detection of TEs in the human genome by using reconstructed ancestral genomes from various species, which allowed them to identify previously undetectable degenerate TEs in the human genome.

The study is published in Cell Genomics.

The scientists used a database of reconstructed ancestral genomes from different kinds of species, like a genomic "time machine." By comparing the human genome with the reconstructed ancestral genomes, they could identify TEs in the latter that, over millions of years, have become degenerate (worn out) in humans.

This comparison allowed them to detect ("annotate") TEs that might have been missed in previous studies that used data only from the human genome.

Using this approach, the scientists uncovered a larger number of TEs than previously known, adding significantly to the share of our DNA that is contributed by TEs.

Furthermore, they could demonstrate that these newly unearthed TE sequences played all the same regulatory roles as their more recent, already identified relatives.

Read more at Science Daily

Researchers 3D-print functional human brain tissue

A team of University of Wisconsin-Madison scientists has developed the first 3D-printed brain tissue that can grow and function like typical brain tissue.

It's an achievement with important implications for scientists studying the brain and working on treatments for a broad range of neurological and neurodevelopmental disorders, such as Alzheimer's and Parkinson's disease.

"This could be a hugely powerful model to help us understand how brain cells and parts of the brain communicate in humans," says Su-Chun Zhang, professor of neuroscience and neurology at UW-Madison's Waisman Center.

"It could change the way we look at stem cell biology, neuroscience, and the pathogenesis of many neurological and psychiatric disorders."

Printing methods have limited the success of previous attempts to print brain tissue, according to Zhang and Yuanwei Yan, a scientist in Zhang's lab.

The group behind the new 3D-printing process described their method today in the journal Cell Stem Cell.

Instead of using the traditional 3D-printing approach, stacking layers vertically, the researchers went horizontally.

They situated brain cells, neurons grown from induced pluripotent stem cells, in a softer "bio-ink" gel than previous attempts had employed.

"The tissue still has enough structure to hold together but it is soft enough to allow the neurons to grow into each other and start talking to each other," Zhang says.

The cells are laid next to each other like pencils laid next to each other on a tabletop.

"Our tissue stays relatively thin and this makes it easy for the neurons to get enough oxygen and enough nutrients from the growth media," Yan says.

The results speak for themselves -- which is to say, the cells can speak to each other.

The printed cells reach through the medium to form connections inside each printed layer as well as across layers, forming networks comparable to human brains.

The neurons communicate, send signals, interact with each other through neurotransmitters, and even form proper networks with support cells that were added to the printed tissue.

"We printed the cerebral cortex and the striatum and what we found was quite striking," Zhang says.

"Even when we printed different cells belonging to different parts of the brain, they were still able to talk to each other in a very special and specific way."

The printing technique offers precision -- control over the types and arrangement of cells -- not found in brain organoids, miniature organs used to study brains.

The organoids grow with less organization and control.

"Our lab is very special in that we are able to produce pretty much any type of neurons at any time. Then we can piece them together at almost any time and in whatever way we like," Zhang says.

"Because we can print the tissue by design, we can have a defined system to look at how our human brain network operates. We can look very specifically at how the nerve cells talk to each other under certain conditions because we can print exactly what we want."

That specificity provides flexibility. The printed brain tissue could be used to study signaling between cells in Down syndrome, interactions between healthy tissue and neighboring tissue affected by Alzheimer's, testing new drug candidates, or even watching the brain grow.

"In the past, we have often looked at one thing at a time, which means we often miss some critical components. Our brain operates in networks. We want to print brain tissue this way because cells do not operate by themselves. They talk to each other. This is how our brain works and it has to be studied all together like this to truly understand it," Zhang says.

"Our brain tissue could be used to study almost every major aspect of what many people at the Waisman Center are working on. It can be used to look at the molecular mechanisms underlying brain development, human development, developmental disabilities, neurodegenerative disorders, and more."

The new printing technique should also be accessible to many labs.

It does not require special bio-printing equipment or culturing methods to keep the tissue healthy, and can be studied in depth with microscopes, standard imaging techniques and electrodes already common in the field.

The researchers would like to explore the potential of specialization, though, further improving their bio-ink and refining their equipment to allow for specific orientations of cells within their printed tissue..

"Right now, our printer is a benchtop commercialized one," Yan says.

Read more at Science Daily

Clown anemonefish seem to be counting bars and laying down the law

We often think of fish as carefree swimmers in the ocean, reacting to the world around them without much forethought. However, new research from the Okinawa Institute of Science and Technology (OIST) suggests that our marine cousins may be more cognizant than we credit them for.

By observing how a colony of clown anemonefish (Amphiprion ocellaris) -- the species of the titular character in Finding Nemo -- reacts to intruders in their sea anemone home, OIST researchers have found that the fish recognize different anemonefish species based on the number of white bars on their bodies.

"The frequency and duration of aggressive behaviors in clown anemonefish was highest toward fish with three bars like themselves," explains Dr. Kina Hayashi from the Marine Eco-Evo-Devo Unit at OIST, first author on the paper published in the Journal of Experimental Biology, "while they were lower with fish with one or two bars, and lowest toward those without vertical bars, which suggests that they are able to count the number of bars in order to recognize the species of the intruder."

The clown anemonefish is normally a gracious host, allowing many different species to visit their sea anemone.

However, should a member of their own species, and which is not part of the colony, enter their home, the largest fish of the colony, referred to as the alpha fish, will aggressively bite and chase out the intruder.

To figure out how these fish determine the species of their visitors, Dr. Hayashi and colleagues conducted two sets of experiments with immature clown anemonefish raised in the lab.

In the first set, they placed different species of anemonefish, with different numbers of white bars, in small cases inside a tank with a clown anemonefish colony and observed how often and for how long the fish would aggressively stare at and circle the case.

In the second set, the researchers presented a colony of clown anemonefish with different plastic discs painted with true-to-life anemonefish coloration and measured the level of aggression towards these models.

The clown anemonefish displayed the most aggressive behavior towards the intruders with three bars like themselves.

Fish and plastic models with two bars were attacked slightly less frequently, while the ones with one or zero bars received the least aggressive response.

Previous studies have shown that clown anemonefish react much stronger to models with vertical rather than horizontal bars, suggesting that the amount of white color or the general presence of white bars is not the deciding factor.

Combined with the observation that the plastic discs, which have no species defining traits other than the vertical bars, received the same response as the live fish, lead the researchers to suggest that the fish appear to be counting the number of vertical white bars to inform their level of aggression toward intruders.

The researchers also discovered a strict hierarchy in the clown anemonefish colonies that determines which fish attack the intruder.

In the wild, a colony typically consists of one alpha female, one beta male, and several gamma juveniles.

The social position within the colony is determined by very slight differences in size.

Anemonefish get their third and final stripe when they metamorphize into either a male or female when they grow large enough, which is why the current alpha uses harsh methods to uphold the status quo, including chasing out colony members if they grow too large.

Though the researchers used immature fish that have yet to metamorphize into males or females, they still observed the same size-based hierarchy, with the largest juvenile taking on the role of alpha and leading the charge against the intruder.

Read more at Science Daily

Bright galaxies put dark matter to the test

For the past year and a half, the James Webb Space Telescope has delivered astonishing images of distant galaxies formed not long after the Big Bang, giving scientists their first glimpses of the infant universe. Now, a group of astrophysicists has upped the ante: Find the tiniest, brightest galaxies near the beginning of time itself, or scientists will have to totally rethink their theories about dark matter.

The team, led by UCLA astrophysicists, ran simulations that track the formation of small galaxies after the Big Bang and included, for the first time, previously neglected interactions between gas and dark matter. They found that the galaxies created are very tiny, much brighter, and form more quickly than they do in typical simulations that don''t take these interactions into account, instead revealing much fainter galaxies.

Small galaxies, also called dwarf galaxies, are present throughout the universe, and are often thought to represent the earliest type of galaxy. Small galaxies are thus especially interesting to scientists studying the origins of the universe. But the small galaxies they find don't always match what they think they should find. Those closest to the Milky Way spin quicker or are not as dense as in simulations, indicating that the models might have omitted something, such as these gas-dark matter interactions.

The new research, published in The Astrophysical Journal Letters, improves the simulations by adding dark matter interactions with gas and finds that these faint galaxies may have been much brighter than expected early in the universe's history, when they were just beginning to form. The authors suggest scientists should try to find small galaxies that are much brighter than expected using telescopes like the Webb telescope. If they only find faint ones, then some of their ideas about dark matter might be wrong.

Dark matter is a type of hypothetical matter that does not interact with electromagnetism or light. Thus, it is impossible to observe using optics, electricity or magnetism. But dark matter does interact with gravity, and its presence has been inferred from the gravitational effects it has on ordinary matter -- the stuff that makes up all the observable universe. Even though 84% of the matter in the universe is thought to be made of dark matter, it has never been detected directly.

All galaxies are surrounded by a vast halo of dark matter, and scientists think that dark matter was essential to their formation. The "standard cosmological model" astrophysicists use to understand galaxy formation describes how clumps of dark matter in the very early universe drew in ordinary matter through gravity, causing the formation of stars and creating the galaxies we see today. Because most dark matter particles -- called cold dark matter -- are thought to move much slower than the speed of light, this process of accumulation would have occurred gradually.

But over 13 billion years ago, prior to the formation of the first galaxies, ordinary matter, consisting of hydrogen and helium gas from the Big Bang, and dark matter were moving relative to one another. The gas streamed at supersonic velocities past dense thickets of more slowly moving dark matter that should have pulled it in to form galaxies.

"Indeed, in models that do not take streaming into account, this is exactly what happens," said Claire Williams, a UCLA doctoral student and the paper's first author. "Gas is attracted to the gravitational pull of dark matter, forms clumps and knots so dense that hydrogen fusion can occur, and thus forms stars like our sun."

But Williams and co-authors on the Supersonic Project team, a group of astrophysicists from the United States, Italy and Japan led by UCLA physics and astronomy professor Smadar Naoz, found if they added the streaming effect of different velocities between dark and ordinary matter to the simulations, the gas landed far away from the dark matter and was prevented from forming stars right away. When the accumulated gas fell back into the galaxy millions of years later, a massive burst of star formation occurred all at once. Because these galaxies had many more young, hot, luminous stars than ordinary small galaxies for a time, they shone much brighter.

"While the streaming suppressed star formation in the smallest galaxies, it also boosted star formation in dwarf galaxies, causing them to outshine the non-streaming patches of the universe," Williams said. "We predict that the Webb telescope will be able to find regions of the universe where galaxies will be brighter, heightened by this velocity. The fact that they should be so bright might make it easier for the telescope to discover these small galaxies, which are typically extremely hard to detect only 375 million years after the Big Bang."

Because dark matter is impossible to study directly, searching for bright patches of galaxies in the early universe could offer an effective test for theories about dark matter, which has been fruitless so far.

"The discovery of patches of small, bright galaxies in the early universe would confirm that we are on the right track with the cold dark matter model because only the velocity between two kinds of matter can produce the type of galaxy we're looking for," said Naoz, the Howard and Astrid Preston Professor of Astrophysics. "If dark matter does not behave like standard cold dark matter and the streaming effect isn't present, then these bright dwarf galaxies won't be found and we need to go back to the drawing board."

Read more at Science Daily

Unprecedented ocean heating shows risks of a world 3°C warmer

Record-high ocean temperatures observed in 2023 could become the norm if the world moved into a climate that is 3.0°C warmer than pre-industrial levels, according to a new study.

From March 2023, the North Atlantic began to show extremely warm temperatures far exceeding anything seen in the past 40 years.

As of August 2023, the North Atlantic was about 1.4°C warmer than the 1982-2011 average.

Analysis of climate model projections showed that last year's extreme ocean conditions were similar to what scientists expect to be the average if global warming reaches 3°C of warming.

Currently, global temperatures have risen by about 1.2°C above pre-industrial levels.

New research, published this month in the Bulletin of the American Meteorological Society, examines the causes of the record-breaking ocean temperatures witnessed in 2023.

Dr Till Kuhlbrodt, of the University of Reading, led the study.

He said: "The extraordinary heat in the North Atlantic and missing sea ice in the Southern Ocean in 2023 tell us the oceans are sounding an alarm. We urgently need to understand exactly why parts of the ocean are warming rapidly so we can prepare for more frequent weather disruption across the planet. How often we get hit by more of these extremes hangs on figuring out what's driving the Atlantic and Southern Oceans into uncharted territory."

Climate connection?

The study highlights that Earth's energy imbalance is likely a key driver of extreme ocean temperatures, as the planet is currently absorbing more than 1.9 watts per square meter more solar energy than it radiates back to space as heat.

Across Earth, over a time span of one year, this is equivalent to roughly 300 times the global annual consumption of electric energy.

This imbalance has grown fast over recent decades mainly due to heat-trapping gases from human activity.

This increasing energy surplus is propelling ocean warming, with more than 90% of the excess energy accumulated by Earth being funnelled into the oceans.

Since 2016 the Atlantic Ocean has warmed faster than other ocean basins in the top 100 meters of ocean.

This enhanced Atlantic warming may be linked to record low levels of sea ice in the Southern Ocean, the researchers suggest.

The rapid Atlantic warming has coincided with a sharp decline in sea ice cover surrounding Antarctica.

In 2023, Antarctic winter sea ice extent reached by far the lowest levels since satellite monitoring began in the late 1970s.

The researchers emphasise the need to quantify how much the rapid Atlantic warming is impacting sea ice cover.

Reliably attributing the oceanic and sea ice extremes will ensure climate models can accurately predict future extremes, which will inform mitigation policies and resilience measures across the globe.

Read more at Science Daily

Source rocks of the first real continents

Geoscientists have uncovered a missing link in the enigmatic story of how the continents developed -- a revised origin story that doesn't require the start of plate tectonics or any external factor to explain their formation. Instead, the findings published last week in Nature Communications, rely solely on internal geological forces that occurred within oceanic plateaus that formed during the first few hundred million years of Earth's history.

A major hurdle in understanding how the continents formed during the Archean Eon (four to 2.5 billion years ago) has been identifying the building blocks of Earth's early crust.

Much of the "new" Archean crust formed during this period comprised a very distinct association of three types of granitoid rocks -- tonalite, trondhjemite and granodiorite (TTG).

Understanding what went into making TTGs and the magmas they formed from has been difficult, because so many geological processes occurred between their initial melting and ultimate crystallization.

Earlier researchers focused on the trace element composition of these rocks, hoping to find clues about TTG magmas and their source.

"We tracked a specific set of trace elements that aren't affected by alteration and pristinely preserve signatures from the original magma that made new TTG crust," said Dr. Matthijs Smit, associate professor and Canada Research Chair at the University of British Columbia's (UBC) Department of Earth, Ocean and Atmospheric Sciences.

"These elements allowed us to look back through the chemical changes that TTG magmas go through and trace the melt compositions back to their initial state and source -- most likely a sort of gabbro."

"Funnily enough, many people have varieties of this type of rock as a kitchen countertop," Dr. Smit says.

"In a way, many people are preparing their dinner on the type of rock that was responsible for making our modern continents."

The Archean TTG crust is still part of the continents today.

For instance, in North America they make up much of the Canadian Interior between the Cordillera mountain belt in the west and the Grenville and Appalachian mountain belts in the east.

The majority of Ontario, Quebec, Manitoba, Saskatchewan, Northwest Territories and Nunavut is made up of Archean crustal fragments that are dominated by TTGs and their slightly younger and more evolved granite counterparts.

"All of these rocks -- and especially their combination -- can be explained by the model we present," said Dr. Smit.

"Ours is a simple model in which TTGs, as well as the younger rocks that TTGs are typically associated with, resulted from the slow burial, thickening and melting of precursor crust that likely resembled oceanic plateaus. The continental crust was destined to develop the way it did, because it kept getting buried further and the rocks at its base had no choice but to melt. In doing so, they made the TTGs that proved a winning recipe for continental survival and growth."

The UBC researchers' discovery of a stand-alone "intra-crustal" mechanism to make TTGs dispels the long-standing theory that Archean TTGs are formed in Earth's first subduction zones and mark the start of plate tectonics.

"There's always been a 'chicken-and-egg' question of which came first -- the start of plate tectonics or TTG magmatism to make new continental crust," says Dr. Smit.

"We show that these things may actually not be directly related. The recognition of the type of source rock makes this leap possible and also takes away the need to have other mechanisms, such as meteorite impact, explain the growth of the first real continents."

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Neanderthals and humans lived side by side in Northern Europe 45,000 years ago

A genetic analysis of bone fragments unearthed at an archaeological site in central Germany shows conclusively that modern humans -- Homo sapiens -- had already reached Northern Europe 45,000 years ago, overlapping with Neanderthals for several thousand years before the latter went extinct.

The findings establish that the site near Ranis, Germany, which is known for its finely flaked, leaf-shaped stone tool blades, is among the oldest confirmed sites of modern human Stone Age culture in north central and northwestern Europe.

The evidence that Homo sapiens and Homo neanderthalensis lived side by side is consistent with genomic evidence that the two species occasionally interbred. It also feeds the suspicion that the invasion of Europe and Asia by modern humans some 50,000 years ago helped drive Neanderthals, which had occupied the area for more than 500,000 years, to extinction.

The genetic analysis, along with an archaeological and isotopic analysis and radiocarbon dating of the Ranis site, are detailed in a trio of papers appearing today in the journals Nature and Nature Ecology and Evolution.

The stone blades at Ranis, referred to as leaf points, are similar to stone tools found at several sites in Moravia, Poland, Germany and the United Kingdom. These tools that are thought to have been produced by the same culture, referred to as the Lincombian-Ranisian-Jerzmanowician (LRJ) culture or technocomplex. Because of previous dating, the Ranis site was known to be 40,000 years old or older, but without recognizable bones to indicate who made the tools, it was unclear whether they were the product of Neanderthals or Homo sapiens.

The new findings demonstrate that "Homo sapiens made this technology, and that Homo sapiens were this far north at this time period, which is 45,000 years ago," said Elena Zavala, one of four first authors of the Nature paper and a Miller Research Fellow at the University of California, Berkeley. "So these are among the earliest Homo sapiens in Europe."

Zavala was a Ph.D. student at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) in Leipzig in 2018 when she first began working on the project, which was a major effort spearheaded by Jean-Jacque Hublin, former director of the institute and a professor at the Collège de France in Paris.

"The Ranis cave site provides evidence for the first dispersal of Homo sapiens across the higher latitudes of Europe. It turns out that stone artifacts that were thought to be produced by Neanderthals were, in fact, part of the early Homo sapiens toolkit," Hublin said. "This fundamentally changes our previous knowledge about the period: Homo sapiens reached northwestern Europe long before Neanderthal disappearance in southwestern Europe."

Bones from maternal relatives?

Zavala conducted the genetic analysis of hominid bone fragments from the new and deeper excavations at Ranis between 2016 and 2022 and from earlier excavations in the 1930s. Because the DNA in ancient bones is highly fragmented, she employed special techniques to isolate and sequence the DNA, all of it mitochondrial DNA (mtDNA) that is inherited solely from the mother.

"We confirmed that the skeletal fragments belonged to Homo sapiens. Interestingly, several fragments shared the same mitochondrial DNA sequences -- even fragments from different excavations," she said. "This indicates that the fragments belonged to the same individual or their maternal relatives, linking these new finds with the ones from decades ago."

The bone fragments were initially identified as human through analysis of bone proteins -- a field called paleoproteomics -- by another first author, Dorothea Mylopotamitaki, a doctoral student at the Collège de France and fomerly of MPI-EVA.

By comparing the Ranis mitochondrial DNA sequences with mtDNA sequences obtained from human remains at other paleolithic sites in Europe, Zavala was able to construct a family tree of early Homo sapiens across Europe. All but one of the 13 Ranis fragments were quite similar to one another and, surprisingly, resembled mtDNA from the 43,000-year-old skull of a woman discovered in a cave at Zlatý k?? in the Czech Republic. The lone standout grouped with an individual from Italy.

"That raises some questions: Was this a single population? What could be the relationship here?" Zavala said. "But with mitochondrial DNA, that's only one side of the history. It's only the maternal side. We would need to have nuclear DNA to be able to start looking into this."

A transitional site between Middle and Upper Paleolithic

Zavala specializes in the analysis of DNA found in long-buried bones, on bone tools and in sediment. Her search through sediment from various levels of the Ranis excavation turned up DNA from a broad array of mammals, but none from hominids. The analysis, combined with morphological, isotopic and proteomic analysis of bone fragments, paints a picture of the environment at that time and of the diet of both humans and animals that occupied the cave over the millennia.

The presence of reindeer, cave bear, woolly rhinoceros and horse bones, for example, indicated cold climatic conditions typical of steppe tundra and similar to conditions in Siberia and northern Scandinavia today, and a human diet based on large terrestrial animals. The researchers concluded that the cave was used primarily by hibernating cave bears and denning hyenas, with only periodic human presence.

"This lower-density archaeological signature matches other Lincombian-Ranisian-Jerzmanowician sites and is best explained by expedient visits of short duration by small, mobile groups of pioneer H. sapiens," according to one of the papers published in Nature Ecology and Evolution.

"This shows that even these earlier groups of Homo sapiens dispersing across Eurasia already had some capacity to adapt to such harsh climatic conditions," said Sarah Pederzani, a postdoctoral fellow at the University of La Laguna in Spain, who led the paleoclimate study of the site. "Until recently, it was thought that resilience to cold-climate conditions did not appear until several thousand years later, so this is a fascinating and surprising result."

The Ranis site, called Ilsenhöhle and located at the base of a castle, was initially excavated mainly between 1932 and 1938. The leaf points found there were eventually assigned to the final years of the Middle Paleolithic period -- between about 300,000 and 30,000 years ago -- or the beginning of the Upper Paleolithic, which begins around 50,000 years ago.

Because of the importance of the Ranis site for understanding the LRJ technocomplex and the transition from the Neanderthal-associated late Middle Paleolithic to the modern human Upper Paleolithic in central Europe, Hublin and his team decided to reexcavate the site using modern tools of archaeology.

The new excavations extended to bedrock, about 8 meters below the surface, and involved removing a rock -- likely fallen from the cave ceiling -- that had halted the previous excavation. Here, Hublin's team uncovered chips from flint tools and a quartzite flake consistent with the LRJ technocomplex. Subsequent proteomic analysis of thousands of recovered bone chips confirmed that four were from hominids. Of bone chips uncovered during the 1930s excavations, nine were from hominids.

Zavala's DNA analysis confirmed that all 13 bone fragments came from Homo sapiens.

A revised settlement history of Northern Europe

The team also carried out radiocarbon dating of human and animal bones from different layers of the site to reconstruct the site's chronology, focusing on bones with traces of human modifications on their surfaces, which links their dates to human presence in the cave.

"We found very good agreement between the radiocarbon dates from the Homo sapiens bones from both excavation collections and with modified animal bones from the LRJ layers of the new excavation, making a very strong link between the human remains and LRJ. The evidence suggests that Homo sapiens were sporadically occupying the site from as early as 47,500 years ago," said another first author, Helen Fewlass, a former Max Planck researcher who is now a European Molecular Biology Organization (EMBO) Postdoctoral Fellow at the Francis Crick Institute in London.

"The results from the Ilsenhöhle in Ranis fundamentally changed our ideas about the chronology and settlement history of Europe north of the Alps," added Tim Schüler of the Thuringian State Office for the Preservation of Historical Monuments and Archaeology in Weimar, Germany.

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Staggering structure in 19 nearby spiral galaxies

It's oh-so-easy to be absolutely mesmerized by these spiral galaxies. Follow their clearly defined arms, which are brimming with stars, to their centers, where there may be old star clusters and -- sometimes -- active supermassive black holes. Only NASA's James Webb Space Telescope can deliver highly detailed scenes of nearby galaxies in a combination of near- and mid-infrared light -- and a set of these images was publicly released today.

These Webb images are part of a large, long-standing project, the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) program, which is supported by more than 150 astronomers worldwide. Before Webb took these images, PHANGS was already brimming with data from NASA's Hubble Space Telescope, the Very Large Telescope's Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array, including observations in ultraviolet, visible, and radio light. Webb's near- and mid-infrared contributions have provided several new puzzle pieces.

"Webb's new images are extraordinary," said Janice Lee, a project scientist for strategic initiatives at the Space Telescope Science Institute in Baltimore. "They're mind-blowing even for researchers who have studied these same galaxies for decades. Bubbles and filaments are resolved down to the smallest scales ever observed, and tell a story about the star formation cycle."

Excitement rapidly spread throughout the team as the Webb images flooded in. "I feel like our team lives in a constant state of being overwhelmed -- in a positive way -- by the amount of detail in these images," added Thomas Williams, a postdoctoral researcher at the University of Oxford in the United Kingdom.

Follow the Spiral Arms

It's oh-so-easy to be absolutely mesmerized by these spiral galaxies. Follow their clearly defined arms, which are brimming with stars, to their centers, where there may be old star clusters and -- sometimes -- active supermassive black holes. Only NASA's James Webb Space Telescope can deliver highly detailed scenes of nearby galaxies in a combination of near- and mid-infrared light.

Webb's NIRCam (Near-Infrared Camera) captured millions of stars in these images, which sparkle in blue tones. Some stars are spread throughout the spiral arms, but others are clumped tightly together in star clusters.

The telescope's MIRI (Mid-Infrared Instrument) data highlights glowing dust, showing us where it exists around and between stars. It also spotlights stars that haven't yet fully formed -- they are still encased in the gas and dust that feed their growth, like bright red seeds at the tips of dusty peaks. "These are where we can find the newest, most massive stars in the galaxies," said Erik Rosolowsky, a professor of physics at the University of Alberta in Edmonton, Canada.

Something else that amazed astronomers? Webb's images show large, spherical shells in the gas and dust. "These holes may have been created by one or more stars that exploded, carving out giant holes in the interstellar material," explained Adam Leroy, a professor of astronomy at the Ohio State University in Columbus.

Now, trace the spiral arms to find extended regions of gas that appear red and orange. "These structures tend to follow the same pattern in certain parts of the galaxies," Rosolowsky added. "We think of these like waves, and their spacing tells us a lot about how a galaxy distributes its gas and dust." Study of these structures will provide key insights about how galaxies build, maintain, and shut off star formation.

Dive Into the Interior

Evidence shows that galaxies grow from inside out -- star formation begins at galaxies' cores and spreads along their arms, spiraling away from the center. The farther a star is from the galaxy's core, the more likely it is to be younger. In contrast, the areas near the cores that look lit by a blue spotlight are populations of older stars.

What about galaxy cores that are awash in pink-and-red diffraction spikes? "That's a clear sign that there may be an active supermassive black hole," said Eva Schinnerer, a staff scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany. "Or, the star clusters toward the center are so bright that they have saturated that area of the image."

Research Galore

There are many avenues of research that scientists can begin to pursue with the combined PHANGS data, but the unprecedented number of stars Webb resolved are a great place to begin. "Stars can live for billions or trillions of years," Leroy said. "By precisely cataloging all types of stars, we can build a more reliable, holistic view of their life cycles."

In addition to immediately releasing these images, the PHANGS team has also released the largest catalog to date of roughly 100,000 star clusters. "The amount of analysis that can be done with these images is vastly larger than anything our team could possibly handle," Rosolowsky emphasized. "We're excited to support the community so all researchers can contribute."

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Some plastic straws degrade quicker than others

Straws are one of the most common plastic waste products found on coastlines. As more and more plastic products are being produced, consumed, and disposed of, scientists and manufacturers are developing alternative materials that work equally as well, and don't contribute to persistent plastic pollution in the environment.

But not all plastics are created the same -- different manufacturers have different formulations of base polymers -- such as polylactic acid (PLA) and polypropylene (PP) -- and chemical additives. That means different plastic formulations behave differently in the environment and break down in the ocean at different rates. There are new materials out in the market that move away from petroleum-derived products -- like cellulose diacetate (CDA), a polymer derived from wood pulp that is widely used in consumer goods -- and Woods Hole Oceanographic Institution (WHOI) scientists have been working to quantify the environmental lifetimes of a wide range of plastic goods to answer the unresolved question, how long do straws last in the ocean?

In a new paper published in ACS Sustainable Chemistry & Engineering, WHOI scientists Collin Ward, Bryan James, Chris Reddy, and Yanchen Sun put different types of plastics and paper drinking straws head-to-head to see which degrade the fastest in the coastal ocean. They partnered with scientists from bioplastic manufacturing company Eastman, who provided funding, contributed as coauthors, and supplied materials for the study.

"We lack a firm understanding of how long plastics last in the ocean, so we've been designing methods to measure how fast these materials degrade," Ward said. "It turns out, in this case, there are some bioplastic straws that actually degrade fairly quickly, which is good news."

Their approach involved suspending eight different types of straws in a tank of continuously flowing seawater from Martha's Vineyard Sound, Massachusetts. This method also controlled the temperature, light exposure, and other environmental variables to mimic the natural marine environment. All straws were monitored for signs of degradation over 16 weeks, and the microbial communities growing on the straws were characterized.

"My interest has been to understand the fate, persistence, and toxicity of plastic and how we can use that information to design next-generation materials that are better for people and the planet," James said. "We have the unique capability where we can bring the environment of the ocean on land in our tanks at the environmental systems laboratory. It gives us a very controlled environment with natural seawater."

They tested straws made of CDA, polyhydroxyalkanoates (PHA), paper, PLA, and PP. In the weeks the straws were submerged in the tanks, the CDA, PHA, and paper straws degraded by up to 50%, projecting environmental lifetimes of 10-20 months in the coastal ocean. The PLA and PP straws showed no measurable signs of degradation.

The scientists then compared two straws made from CDA -- one a solid and the other a foam, both provided by Eastman. The straw made from foamed CDA was a prototype to see if increasing the surface area would accelerate break down. They found that the degradation rate of the foam straw was 184% faster than its solid counterpart, resulting in a shorter projected environmental lifetime than the paper straws.

"The unique aspects of this foam straw are that it's able to have a shorter expected lifetime than the paper straws but retain the properties that you enjoy of a plastic or a bioplastic straw," James said, making it a promising alternative to conventional plastic straws compared to paper straws, which degrade quickly in the ocean but sour user experience by getting soggy, according to the authors.

"This study can be immensely valuable for straw manufacturers by providing informed and transparent data when selecting a material for straws. Even more, it provides reassurance that CDA-based straws won't add to the persistent plastic pollution, while also demonstrating straw manufacturers' commitment to offering a sustainable product that reduces risk to marine life," said Jeff Carbeck, Eastman's Vice President of Corporate Innovation.

Science supports a push away from conventional plastic material. Plastic pollution causes harm to humans and ecosystems and the plastic industry is a large-scale contributor to climate change, accounting for roughly 4 to 5% of all greenhouse gas emissions across their lifecycle. With plastic waste becoming ubiquitous in the global ocean and marine food chain over the past 50 years, it's important to identify new materials that are sustainably sourced, contribute to the shift from a linear to a circular economy, and break down if they incidentally leak into the environment.

"While some push to shift away from plastics, the reality is that plastics are here to stay. We're trying to accept the fact that these materials are going to be used by consumers, and then we can work with companies to minimize the impacts of them should they leak into the environment," Ward said.

"We recognize the importance of testing, validating and understanding the marine degradation of our CDA based products, but lacked the necessary resources," Carbeck said. "Knowing that WHOI possessed the expertise and facilities, we engaged in a collaborative effort to address this challenge. This partnership showcases the power of industry-academia collaboration in advancing shared goals and making a positive impact."

The research team also found that the microbial communities of the straws that degraded were unique to each straw material. However, the microbial communities on both non-degrading straws were the same despite having vastly different chemical structures. This provided further evidence that the native microbes were degrading the biodegradable straws, whereas the non-biodegradable straws likely persist in the ocean.

"Our understanding of the impacts of plastic pollution on ocean health are really uncertain, and a lot of this boils down to not know the long-term fates of these materials," Ward said. He and the rest of the research team plan to continue measuring the degradability of plastic materials, with the hope of guiding where the industry goes next.

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People are inclined to hide a contagious illness while around others, research shows

A startling number of people conceal an infectious illness to avoid missing work, travel, or social events, new research at the University of Michigan suggests.

The findings are reported in Psychological Science, a journal of the Association for Psychological Science.

Across a series of studies involving healthy and sick adults, 75% of the 4,110 participants said they had either hidden an infectious illness from others at least once or might do so in the future.

Many participants reported boarding planes, going on dates, and engaging in other social interactions while secretly sick.

More than 61% of healthcare workers participating in the study also said they had concealed an infectious illness.

Interestingly, the researchers found a difference between how people believe they would act when ill and how they actually behave, said Wilson N. Merrell, a doctoral candidate and lead author on the study.

"Healthy people forecasted that they would be unlikely to hide harmful illnesses -- those that spread easily and have severe symptoms -- but actively sick people reported high levels of concealment regardless of how harmful their illness was to others," Merrell said.

In the first study, Merrell and his colleagues -- psychology professor Joshua M. Ackerman and PhD student Soyeon Choi -- recruited 399 university healthcare employees and 505 students.

The participants reported the number of days they felt symptoms of an infectious illness, starting in March 2020, when the COVID-19 pandemic began.

They then rated how often they actively covered up symptoms from others, came to campus or work without telling others they were feeling ill, or falsified mandatory symptom screeners that the university had required for anyone using campus facilities.

More than 70% of the participants reported covering up their symptoms.

Many said they hid their illness because it would conflict with social plans, while a small percentage of participants cited pressure from institutional policies (e.g., lack of paid time off). Only five participants reported hiding a COVID-19 infection.

In a second study, the researchers recruited 946 participants online and randomly assigned them to one of nine conditions in which they imagined being either moderately or severely sick while in a social situation.

In each condition, the risk of spreading the illness was designated as low, medium, or high.

(To control for the special stigma associated with COVID-19 at the time, the researchers asked participants not to imagine being sick with that disease.) Participants were most likely to envision themselves hiding their sickness when symptom severity was low, and least likely to conceal when symptoms were severe and highly communicable.

In another study, Merrell and colleagues used an online research tool to recruit 900 people --

including some who were actively sick -- and asked them to rate the transmissibility of their real or imagined illness.

The participants were also asked to rate their likelihood of covering up an illness in a hypothetical meeting with another person.

Results showed that compared to healthy participants who only imagined being sick, those who were actively ill were more likely to conceal their illness regardless of its transmissibility.

"This suggests that sick people and healthy people evaluate the consequences of concealment in different ways," Merrell said, "with sick people being relatively insensitive to how spreadable and severe their illness may be for others."

The COVID-19 crisis may have shaped the way the participants thought about concealing an illness, Merrell said, adding that future research could explore how ecological factors (e.g., pandemics) and medical advances such as vaccines influence people's disease-related behavior.

The research team is also expanding this line of investigation to other countries to uncover potential cultural differences in concealment behaviors, he said.

Overall, the findings carry significant public health implications, illuminating the motivations and tradeoffs we make in social interactions when we're sick, Merrell added.

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Music causes similar emotions and bodily sensations across cultures

Music can be felt directly in the body. When we hear our favourite catchy song, we are overcome with the urge to move to the music. Music can activate our autonomic nervous system and even cause shivers down the spine. A new study from the Turku PET Centre in Finland shows how emotional music evokes similar bodily sensations across cultures.

"Music that evoked different emotions, such as happiness, sadness or fear, caused different bodily sensations in our study. For example, happy and danceable music was felt in the arms and legs, while tender and sad music was felt in the chest area," explains Academy Research Fellow Vesa Putkinen.

The emotions and bodily sensations evoked by music were similar across Western and Asian listeners.

The bodily sensations were also linked with the music-induced emotions.

"Certain acoustic features of music were associated with similar emotions in both Western and Asian listeners. Music with a clear beat was found happy and danceable while dissonance in music was associated with aggressiveness. Since these sensations are similar across different cultures, music-induced emotions are likely independent of culture and learning and based on inherited biological mechanisms," says Professor Lauri Nummenmaa.

"Music's influence on the body is universal. People move to music in all cultures and synchronized postures, movements and vocalizations are a universal sign for affiliation. Music may have emerged during the evolution of human species to promote social interaction and sense of community by synchronising the bodies and emotions of the listeners," continues Putkinen.

The study was conducted in collaboration with Aalto University from Finland and the University of Electronic Science and Technology of China (UESTC) as an online questionnaire survey.

Altogether 1,500 Western and Asian participants rated the emotions and bodily sensations evoked by Western and Asian songs.

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Researchers spying for signs of life among exoplanet atmospheres

The next generation of advanced telescopes could sharpen the hunt for potential extraterrestrial life by closely scrutinizing the atmospheres of nearby exoplanets, new research suggests.

The next generation of advanced telescopes could sharpen the hunt for potential extraterrestrial life by closely scrutinizing the atmospheres of nearby exoplanets, new research suggests.

Published recently in The Astronomical Journal, a new paper details how a team of astronomers from The Ohio State University examined upcoming telescopes' ability to detect chemical traces of oxygen, carbon dioxide, methane and water on 10 rocky exoplanets. These elements are biosignatures also found in Earth's atmosphere that can provide key scientific evidence of life.

The study found that for a pair of these nearby worlds, Proxima Centauri b and GJ 887 b, these telescopes are highly adept at detecting the presence of potential biosignatures. Of the two, findings show that only for Proxima Centauri b would the machines be able to detect carbon dioxide if it were present. Though no exoplanet has been found to precisely twin Earth's early conditions for life, this work suggests that if examined in greater detail, such unique Super Earths -- planets more massive than Earth but smaller than Neptune -- could make a suitable target for future research missions.

To further the search for habitable planets, Huihao Zhang, lead author of the study and a senior in astronomy at Ohio State, and his colleagues also sought to determine the effectiveness of specialized imaging instruments like the James Webb Space Telescope (JWST) and other Extremely Large Telescopes (ELTs) such as the European Extremely Large Telescope, the Thirty-Meter-Telescope and the Giant Magellan Telescope at directly imaging exoplanets.

"Not every planet is suitable for direct imaging, but that's why simulations give us a rough idea of what the ELTs would have delivered and the promises they're meant to hold when they are built," said Zhang.

The direct method of imaging exoplanets involves using a coronagraph or starshade to block a host star's light, allowing for scientists to capture a faint image of the new world in orbit. But because locating them in this way can be difficult and time-consuming, the researchers aimed to see how well the ELT telescopes might handle the challenge. To do this, they tested each telescope's instruments' abilities to differentiate universal background noise from the planetary noise they aimed to capture while detecting biosignatures; called the signal-to-noise ratio, the higher it is, the easier a planet's wavelength is able to be detected and analyzed.

Results showed that the direct imaging mode of one of the European ELT's instruments, called the Mid-infrared ELT Imager and Spectrograph, performed better for three planets (GJ 887 b, Proxima b and Wolf 1061 c) in discerning the presence of methane, carbon dioxide and water, while its High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph instrument could detect methane, carbon dioxide, oxygen and water, but needed a great deal more exposure time.

Additionally, since these conclusions were about instruments that will have to peer through the chemical fog of Earth's atmosphere to progress the search for cosmic life, they were compared to JWST's current outer space capabilities, said Zhang.

"It's hard to say whether space telescopes are better than ground-based telescopes, because they're different," he said. "They have different environments, different locations, and their observations have different influences."

In this case, findings revealed that while GJ 887 b is one of the most suitable targets for ELT direct imaging as its location and size result in an especially high signal-to-noise ratio, for some transiting planets, such as the TRAPPIST-1 system, JWST's techniques for studying planetary atmospheres are more suitable for detecting them than direct imaging from the ELTs on Earth.

But because the study took on a more conservative assumption with the data, Zhang said, the true effectiveness of future astronomical tools could still surprise scientists. And subtle contrasts in performance aside, these powerful technologies serve to widen our understanding of the universe and are meant to complement each other, said Ji Wang, co-author of the study and an assistant professor in astronomy at Ohio State. It's why studies like this one, that assess the limitations of those technologies, is necessary, he said.

"The importance of simulation, especially for missions that cost billions of dollars, cannot be stressed enough," said Wang. "Not only do people have to build the hardware, they also try really hard to simulate the performance and be prepared to achieve those glorious results."

In all likelihood, as the ELTs won't be completed until the tail end of the decade, researchers' next steps will settle around simulating how well future ELT instruments will take to investigating the intricacies of our own planet's rampant proofs of life.

"We want to see to what extent we can study our atmosphere to exquisite detail and how much information we can extract from it," said Wang. "Because if we cannot answer habitability questions with Earth's atmosphere, then there's no way we can start to answer these questions around other planets."

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Rising sea levels could lead to more methane emitted from wetlands

As sea levels rise due to global warming, ecosystems are being altered. One small silver lining, scientists believed, was that the tidal wetlands found in estuaries might produce less methane -- a potent greenhouse gas -- as the increasing influx of seawater makes these habitats less hospitable to methane-producing microbes.

However, research from biologists at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley indicates that these assumptions aren't always true. After examining the microbial, chemical, and geological features of 11 wetland zones, the team found that a wetland region exposed to a slight amount of seawater was emitting surprisingly high levels of methane -- far more than any of the freshwater sites.

Their results, now published in mSystems, indicate that the factors governing how much greenhouse gas is stored or emitted in natural landscapes are more complex and difficult to predict than we thought.

"We looked at how many methanogens, the organisms that make methane, are present in soils at these sites and it wasn't really well correlated with the amount of methane observed," said senior author Susannah Tringe, director of Berkeley Lab's Environmental Genomics & Systems Biology Division. "And even if you look at the amount of methanotrophs, organisms that eat methane, in combination with methanogens, that doesn't seem to fully explain it."

Tringe and her colleagues took soil samples from the 11 sites and used high-throughput sequencing to analyze DNA from organisms found in the samples, including bacteria, viruses, and fungi. They examined what genes were present in the sequences and mapped them to known functions -- for example, identifying genes known to be involved in metabolizing nitrogen or genes from bacteria that use sulfate during respiration. Then they worked to model how the genetic information they found, combined with chemical factors in the soil and water, could result in the methane emissions they observed.

Across most of the sites, which ranged from freshwater to full seawater salinities, the amount of methane emitted was inversely related to the amount of salt water that was flowing in and mingling with the river water. But at one site, which had been restored in 2010 from a seasonal grassy pasture for livestock grazing back to its original wetland habitat, the team saw high methane emissions despite the moderate amount of salt water.

Seawater contains more sulfate (an ion with sulfur and oxygen) than freshwater, leading to the assumption that increased influx of seawater in these environments would lead to less methane production as the methanogens that use CO2 to make cellular energy are outcompeted by the bacteria that use sulfate instead.

"Ultimately, we found that there were significant influences from other bacterial groups like the ones that break down carbon and even organisms that are better known as nitrogen cyclers, and we couldn't readily explain the methane emissions by something as simple as, for example, how much sulfate is available or how many methanogens are there," said Tringe.

Another concept in ecology is that restoring habitats to their native state can boost carbon storage, improve water quality, and increase wildlife populations. In recent decades, wetlands have been increasingly recognized as critical ecosystems for these environmental services, leading to widespread efforts to restore ecosystems by removing barriers, pollution, and non-native organisms.

Modeling work by co-author Dennis D. Baldocchi, Executive Associate Dean and professor of Biometeorology at UC Berkeley, suggests that although the restored wetland is adding greenhouse gas to the atmosphere currently, the ecosystem will stabilize and begin to serve as a net carbon sink within 100 to 150 years. This may not be the timeline that stakeholders were hoping for when they restored the area with the goal of carbon sequestration.

"We want to know if these systems will act as long-term carbon sinks," said Baldocchi. "And these microbiological investigations can help refine our models and predictions."

Tringe noted that other labs have observed increased methane production from wetland soils with increased salinity. Scientists from Duke University took soil core samples from a coastal freshwater wetland and exposed them to artificial seawater, and artificial seawater lacking sulfate. In both cases, methane production went up. Tringe's lab recently collaborated with Marcelo Ardón of North Carolina State University to analyze the microbial communities in those soils.

"There was this expectation that sulfate would be the most important thing. And in those studies, not only did salt water stimulate methane production, which again is kind of counter to the dogma that sulfate is important, it happened whether you had sulfate there or not; in fact the sulfate didn't have a big effect on the methane emissions," said Tringe. "So I think these experimental manipulations are reconfirming the story that there's more nuanced effects of seawater intrusion than just a sulfate addition, and also more nuanced factors behind ecosystem restoration."

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Excavated dolmen in Sweden one of the oldest in Scandinavia

The first analysis results now confirm that the grave in Tiarp is one of the oldest stone burial chambers in Sweden. "It's an early grave which dates to the Early Neolithic period, about 3500 BCE," says archaeologist Karl-Göran Sjögren. The researchers also noted that some parts of the people buried in the grave are missing, such as skulls and thigh bones, posing intriguing questions for archaeologists.

Last summer, archaeologists from Gothenburg University and Kiel University excavated a dolmen, a stone burial chamber, in Tiarp near Falköping in Sweden.

The archaeologists judge that the grave has remained untouched since the Stone Age.

However, the odd thing is that parts of the skeletons of the people buried are missing.

Skulls and large bones are missing and may have been removed from the grave.

Now that the researchers have examined the material from the grave, they have found that it contains bones from hands and feet, fragments of rib bones and teeth.

But skulls and larger bones such as thigh and arm bones are very few.

"This differs from what we usually see in megalith graves, i.e. stone burial chambers from the Neolithic period," Karl-Göran Sjögren explains.

"Usually, the bones that are missing are smaller bones from feet and hands."

Torbjörn Ahlström, Professor of Osteology at Lund University, studied the bone finds.

His conclusion is that the bones come from at least twelve people, including infants and the elderly.

But the archaeologists don't yet know why they died.

"We haven't seen any injuries on the people buried so we don't think violence is involved. But we are continuing to study their DNA and that will show whether they had any diseases," says Karl-Göran Sjögren.

Falköping has long been known for its many passage graves dating from a somewhat later period, approximately 3300 BCE.

Agriculture reached Falbygden in about 4000 BCE, i.e. about 500 years before the grave in Tiarp was built.

In all likelihood, the people buried in the dolmen were farmers.

"They lived by growing grain and keeping animals and they consumed dairy products," says Karl-Göran Sjögren.

Are the people buried in the grave related?

A number of samples were taken at the excavation last summer, including DNA from the skeletal remains.

"The preliminary DNA results show that the DNA in the bones is well preserved. This means we will be able to reconstruct the family relationships between the people in the grave and we are working on that now," says Karl-Göran Sjögren.

Falbygden is known for its many traces of people from the Stone Age.

There are more than 250 passage graves here, large graves built of blocks of stone.

"But this dolmen is older. It's about 200 to 150 years older than the passage graves, making it one of the oldest stone burial chambers in Sweden and across the whole of Scandinavia," says Karl-Göran Sjögren.

There is another thing that makes the grave unique.

"It's the way it is constructed. There's a little niche at each end. This is unique for graves in Falbygden," says Karl-Göran Sjögren.

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First-ever sighting of a live newborn great white

Great whites, the largest predatory sharks in the world with the most fatal attacks on humans, are tough to imagine as newborn babies. That is partially because no one has seen one in the wild, it seems, until now.

Wildlife filmmaker Carlos Gauna and UC Riverside biology doctoral student Phillip Sternes were scanning the waters for sharks on July 9, 2023, near Santa Barbara on California's central coast.

That day, something exciting appeared on the viewfinder of Gauna's drone camera.

It was a shark pup unlike any they'd ever seen.

Great whites, referred to only as white sharks by scientists, are gray on top and white on the bottom.

But this roughly 5-foot-long shark was pure white.

"We enlarged the images, put them in slow motion, and realized the white layer was being shed from the body as it was swimming," Sternes said.

"I believe it was a newborn white shark shedding its embryonic layer."

These observations are documented in a new paper in the Environmental Biology of Fishes journal.

The paper also details the significance of having seen a live newborn white shark.

Gauna is known online as The Malibu Artist. He has spent thousands of hours filming sharks around the world, and his videos of them swimming close to beachgoers have millions of views.

What he and Sternes observed could help solve the longstanding mystery of great white birthing habits.

"Where white sharks give birth is one of the holy grails of shark science. No one has ever been able to pinpoint where they are born, nor has anyone seen a newborn baby shark alive," Gauna said.

"There have been dead white sharks found inside deceased pregnant mothers. But nothing like this."

Though the paper authors acknowledge it is possible the white film the shark shed could have been a skin condition, the duo do not believe this to be the case.

"If that is what we saw, then that too is monumental because no such condition has ever been reported for these sharks," Gauna said.

For many reasons, the duo believes what they saw was in fact a newborn great white.

First, great white females give birth to live pups. While in utero, the embryonic sharks might feed on unfertilized eggs for protein.

The mothers offer additional nourishment to the growing shark pups with a 'milk' secreted in the uterus.

"I believe what we saw was the baby shedding the intrauterine milk," Sternes said.

A second reason is the presence of large, likely pregnant great whites in this location.

Gauna had observed them here in previous years, and in the weeks leading up to the observation.

"I filmed three very large sharks that appeared pregnant at this specific location in the days prior. On this day, one of them dove down, and not long afterwards, this fully white shark appears," Gauna said.

"It's not a stretch to deduce where the baby came from."

Thirdly, the shark's size and shape are also indicative of a newborn.

What the two observed was thin, short, and rounded. "In my opinion, this one was likely hours, maybe one day old at most," Sternes said.

Finally, this location off the coast of central California has long been proposed as a birthing location for great whites.

"There are a lot of hypothetical areas, but despite intense interest in these sharks, no one's seen a birth or a newborn pup in the wild," Sternes said.

"This may well be the first evidence we have of a pup in the wild, making this a definitive birthing location."

Many scholars believe great whites are born farther out at sea.

That this pup was filmed so close to shore -- roughly 1,000 feet from the beach -- is significant because its age means it was likely born in shallow waters.

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Confirmation of ancient lake on Mars builds excitement for Perseverance rover's samples

If life ever existed on Mars, the Perseverance rover's verification of lake sediments at the base of the Jezero crater reinforces the hope that traces might be found in the crater.

In new research published in the journal Science Advances, a team led by UCLA and The University of Oslo shows that at some point, the crater filled with water, depositing layers of sediments on the crater floor.

The lake subsequently shrank and sediments carried by the river that fed it formed an enormous delta.

As the lake dissipated over time, the sediments in the crater were eroded, forming the geologic features visible on the surface today.

The periods of deposition and erosion took place over eons of environmental changes, the radar indicates, confirming that inferences about the Jezero crater's geologic history based on Mars images obtained from space are accurate.

"From orbit we can see a bunch of different deposits, but we can't tell for sure if what we're seeing is their original state, or if we're seeing the conclusion of a long geological story," said David Paige, a UCLA professor of Earth, planetary and space sciences and first author of the paper.

"To tell how these things formed, we need to see below the surface."

The rover, which is about the size of a car and carries seven scientific instruments, has been exploring the 30-mile-wide crater, studying its geology and atmosphere and collecting samples since 2021.

Perseverance's soil and rock samples will be brought back to Earth by a future expedition and studied for evidence of past life.

Between May and December 2022, Perseverance drove from the crater floor onto the delta, a vast expanse of 3 billion-year-old sediments that, from orbit, resembles the river deltas on Earth.

As the rover drove onto the delta, Perseverance's Radar Imager for Mars' Subsurface Experiment, or RIMFAX, instrument fired radar waves downward at 10-centimeter intervals and measured pulses reflected from depths of about 20 meters below the surface.

With the radar, scientists can see down to the base of the sediments to reveal the top surface of the buried crater floor.

Years of research with ground-penetrating radar and testing of RIMFAX on Earth have taught scientists how to read the structure and composition of subsurface layers from their radar reflections.

The resulting subsurface image shows rock layers that can be interpreted like a highway road cut.

"Some geologists say that the ability of radar to see under the surface is kind of like cheating," said Paige, who is RIMFAX's deputy principal investigator.

RIMFAX imaging revealed two distinct periods of sediment deposition sandwiched between two periods of erosion.

UCLA and the University of Oslo report that the crater floor below the delta is not uniformly flat, suggesting that a period of erosion occurred prior to the deposition of lake sediments.

The radar images show that the sediments are regular and horizontal -- just like sediments deposited in lakes on Earth.

The existence of lake sediments had been suspected in previous studies, but has been confirmed by this research.

A second period of deposition occurred when fluctuations in the lake level allowed the river to deposit a broad delta that once extended far out into the lake, but has now eroded back closer to the river's mouth.

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Education and information can increase the acceptance of climate policies

An important question for policymakers worldwide is how to make climate and environmental policies acceptable among the populations. A new study sheds light on the preferences in five East African countries. The study shows, among others, that education and information about how revenues from carbon taxes are used are important factors.

Making climate policies acceptable to the public is crucial to make them effective and to avoid resistance and protests.

Research has, until now, focused on high-income countries. This new study, however, is based on a survey with 4,766 respondents in Ethiopia, Kenya, Rwanda, Tanzania, and Uganda.

It turns out that there are both similarities and differences compared to previous studies.

Important inform how revenues will be used

The researchers focused on educated individuals in urban areas since they are likely to influence policy processes.

This also means that the sample does not fully represent the total East African population.

One conclusion, that aligns with previous studies, is that a higher level of education and climate change concern are linked to a higher acceptance of policies aimed at reducing fossil fuel consumption.

If you specify how the revenue from a climate tax or subsidy removal would be used, the support for these policy instruments almost doubled.

Social programs more important than environmental

In contrast to earlier studies, the researchers found that investments in social programs, not environmental programs, increased the acceptability the most.

"One possible explanation would be that in a country where poverty is prevalent, social issues are more urgent to people," says Daniel Slunge, one of the study's authors.

Trust in government didn't seem to play a big role for the acceptance.

There were also significant differences between the countries.

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How obesity dismantles our mitochondria

The number of people with obesity has nearly tripled since 1975, resulting in a worldwide epidemic. While lifestyle factors like diet and exercise play a role in the development and progression of obesity, scientists have come to understand that obesity is also associated with intrinsic metabolic abnormalities. Now, researchers from University of California San Diego School of Medicine have shed new light on how obesity affects our mitochondria, the all-important energy-producing structures of our cells.

In a study published January 29, 2023 in Nature Metabolism, the researchers found that when mice were fed a high-fat diet, mitochondria within their fat cells broke apart into smaller mitochondria with reduced capacity for burning fat.

Further, they discovered that this process is controlled by a single gene.

By deleting this gene from the mice, they were able to protect them from excess weight gain, even when they ate the same high-fat diet as other mice.

"Caloric overload from overeating can lead to weight gain and also triggers a metabolic cascade that reduces energy burning, making obesity even worse," said Alan Saltiel, PhD, professor in the Department of Medicine at UC San Diego School of Medicine.

"The gene we identified is a critical part of that transition from healthy weight to obesity."

Obesity, which affects more than 40% of adults in the United States, occurs when the body accumulates too much fat, which is primarily stored in adipose tissue.

Adipose tissue normally provides important mechanical benefits by cushioning vital organs and providing insulation.

It also has important metabolic functions, such as releasing hormones and other cellular signaling molecules that instruct other tissues to burn or store energy.

In the case of caloric imbalances like obesity, the ability of fat cells to burn energy starts to fail, which is one reason why it can be difficult for people with obesity to lose weight.

How these metabolic abnormalities start is among the biggest mysteries surrounding obesity.

To answer this question, the researchers fed mice a high-fat diet and measured the impact of this diet on their fat cells' mitochondria, structures within cells that help burn fat.

They discovered an unusual phenomenon. After consuming a high-fat diet, mitochondria in parts of the mice's adipose tissue underwent fragmentation, splitting into many smaller, ineffective mitochondria that burned less fat.

In addition to discovering this metabolic effect, they also discovered that it is driven by the activity of single molecule, called RaIA.

RaIA has many functions, including helping break down mitochondria when they malfunction.

The new research suggests that when this molecule is overactive, it interferes with the normal functioning of mitochondria, triggering the metabolic issues associated with obesity.

"In essence, chronic activation of RaIA appears to play a critical role in suppressing energy expenditure in obese adipose tissue," said Saltiel.

"By understanding this mechanism, we're one step closer to developing targeted therapies that could address weight gain and associated metabolic dysfunctions by increasing fat burning."

By deleting the gene associated with RaIA, the researchers were able to protect the mice against diet-induced weight gain.

Delving deeper into the biochemistry at play, the researchers found that some of the proteins affected by RaIA in mice are analogous to human proteins that are associated with obesity and insulin resistance, suggesting that similar mechanisms may be driving human obesity.

"The direct comparison between the fundamental biology we've discovered and real clinical outcomes underscores the relevance of the findings to humans and suggests we may be able to help treat or prevent obesity by targeting the RaIA pathway with new therapies," said Saltiel "We're only just beginning to understand the complex metabolism of this disease, but the future possibilities are exciting."

Read more at Science Daily