Genetic discovery holds implications for better immunity, longer life

Caenorhabditis elegans.

Wrinkles on the skin of a microscopic worm might provide the key to a longer, healthier life for humans.

Working with Caenorhabditis elegans, a transparent nematode found in soil, researchers at Washington State University's Elson S. Floyd College of Medicine were the first to find that the nervous system controls the tiny worm's cuticle, a skin-like exterior barrier, in response to bacterial infections. Their study was published today in Science Advances.

Often used in biologic research as a model organism, the C. elegans nematode has a relatively simple structure while still sharing several genetic similarities with more complex mammals including humans, so this discovery holds implications for human health as well.

"Our study challenges the traditional view that a physical barrier such as a worm's cuticle or a human's skin does not respond to infections but is part of the body's innate defense against a pathogen," said Assistant Professor Jingru Sun, the corresponding author on the paper. "We show that during infection the nematode can change its cuticle structure and that defense response is controlled by the nervous system."

Sun and her colleagues used technologies such as gene silencing and CRISPR gene editing to show that a G-protein-coupled receptor tied to a gene called npr-8 regulates collagens, proteins that are the key structural components of the nematode's cuticle. Nematodes whose NPR-8 receptor was removed survived longer when exposed to the pathogens that cause pneumonia, salmonella and staph infections. The cuticle of the nematodes without the receptor also remained smooth compared to their wild peers whose cuticle wrinkled in response to the same pathogens.

"For nematodes, it's important to maintain a healthy cuticle that acts as the first line of defense against external insults," said Durai Sellegounder, lead author on the paper and a postdoctoral researcher in Sun's Lab. "Many pathogens produce wicked proteins that try to destroy this barrier and establish infection. Our results show that the nervous system can detect these attacks and respond by remodeling or strengthening this protective structure."

Collagens are the most abundant proteins found in mammals, and declining collagen levels are associated with aging. For humans, collagen loss can create more problems than just unsightly wrinkles. While nematodes have only one "extracellular matrix," the cuticle, humans have an extracellular matrix on every organ and if that matrix is too stiff or too loose it can be harmful.

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Highest-energy light from a gamma-ray burst ever

Gamma-ray bursts are the most powerful explosions in the cosmos. These explosive events last a fraction of a second to several minutes and emit the same amount of gamma rays as all the stars in the universe combined. Such extreme amounts of energy can only be released during catastrophic events like the death of a very massive star, or the merging of two compact stars, and are accompanied by an afterglow of light over a broad range of energies that fades with time.

It has been decades since the discovery of the first gamma-ray burst, yet some of their fundamental traits remain unclear. An international team of researchers, including two astrophysicists from the George Washington University, Chryssa Kouveliotou and Alexander van der Horst, now has taken the next step in understanding the physical processes at work during these events with a recent discovery published today in the journal Nature.

The researchers observed a gamma-ray burst with an afterglow that featured the highest energy photons -- a trillion times more energetic than visible light -- ever detected in a burst.

"This very high energy emission had been previously predicted in theoretical studies but never before directly observed," Dr. van der Horst, an assistant professor of physics at GW, said.

"After over 45 years of observing GRBs, we just confirmed the existence of yet another unknown component in their afterglows, which increases the gamma-ray burst overall energy budget dramatically," Dr. Kouveliotou, a professor of physics at GW, added.

On Jan. 14, 2019, researchers detected a burst labeled GRB 190114C. The discovery triggered an extensive campaign of observations across the electromagnetic spectrum using more than 20 observatories and instruments around the world. This collaborative effort allowed an international team to gather an unprecedented level of information about GRB 190114C, capturing the evolution of the gamma-ray burst afterglow emission across 17 orders of magnitude in energy.

As part of the joint efforts, Dr. van der Horst and Dr. Kouveliotou were part of a subteam responsible for tracking the emission of radio waves in the afterglow of GRB 190114C. The team used the new MeerKAT radio telescope in South Africa to record the emission, which is at the opposite end of the spectrum compared to very high energy gamma rays.

"MeerKAT is a new radio observatory with very good sensitivity," Dr. van der Horst said. "It is a great facility to observe this kind of event. Our team is carrying out a multi-year program to observe many more gamma-ray bursts and other cosmic explosions in the coming years."

GRB 190114C is unique in that researchers were able to observe photons with teraelectronvolt (TeV) energies for the first time in its afterglow emission. Using the MAGIC Collaboration telescopes in La Palma, Spain, researchers noticed this emission of TeV photons was 100 times more intense than the brightest known steady source at TeV energies, the Crab Nebula. As expected though, this very high energy emission quickly faded in about half an hour after the event onset, while the afterglow emission in other parts of the spectrum persisted for much longer.

The researchers noted that the shape of the observed spectrum of afterglow light was indicative of an emission process called inverse Compton emission. This event supports the possibility that inverse Compton emission is commonly produced in gamma-ray bursts.

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Little-known protein appears to play important role in obesity and metabolic disease

With unexpected findings about a protein that's highly expressed in fat tissue, scientists at Scripps Research have opened the door to critical new understandings about obesity and metabolism. Their discovery, which appears Nov. 20 in the journal Nature, could lead to new approaches for addressing obesity and potentially many other diseases.

The signaling protein, known as PGRMC2, had not been extensively studied in the past. Short for "progesterone receptor membrane component 2," it had been detected in the uterus, liver and several areas of the body. But the lab of Enrique Saez, PhD, saw that it was most abundant in fat tissue -- particularly in brown fat, which turns food into heat to maintain body temperature -- and became interested in its function there.

An important role: heme's travel guide

The team built on their recent discovery that PGRMC2 binds to and releases an essential molecule called heme. Recently in the spotlight for its role in providing flavor to the plant-based Impossible Burger, heme holds a much more significant role in the body. The iron-containing molecule travels within cells to enable crucial life processes such as cellular respiration, cell proliferation, cell death and circadian rhythms.

Using biochemical techniques and advanced assays in cells, Saez and his team found that PGRMC2 is a "chaperone" of heme, encapsulating the molecule and transporting it from the cell's mitochondria, where heme is created, to the nucleus, where it helps carry out important functions. Without a protective chaperone, heme would react with -- and destroy -- everything in its path.

"Heme's significance to many cellular processes has been known for a long time," says Saez, associate professor in the Department of Molecular Medicine. "But we also knew that heme is toxic to the cellular materials around it and would need some sort of shuttling pathway. Until now, there were many hypotheses, but the proteins that traffic heme had not been identified."

An innovative approach for obesity?

Through studies involving mice, the scientists established PGRMC2 as the first intracellular heme chaperone to be described in mammals. However, they didn't stop there; they sought to find out what happens in the body if this protein doesn't exist to transport heme.

And that's how they made their next big discovery: Without PGRMC2 present in their fat tissues, mice that were fed a high-fat diet became intolerant to glucose and insensitive to insulin -- hallmark symptoms of diabetes and other metabolic diseases. By contrast, obese-diabetic mice that were treated with a drug to activate PGRMC2 function showed a substantial improvement of symptoms associated with diabetes.

"We saw the mice get better, becoming more glucose tolerant and less resistant to insulin," Saez says. "Our findings suggest that modulating PGRMC2 activity in fat tissue may be a useful pharmacological approach for reverting some of the serious health effects of obesity."

The team also evaluated how the protein changes other functions of brown and white fat, says the study's lead author, Andrea Galmozzi, PhD. "The first surprise finding was that the brown fat looked white," he says.

Brown fat, which is normally the highest in heme content, is often considered the "good fat." One of its key roles is to generate heat to maintain body temperature. Among mice that were unable to produce PGRMC2 in their fat tissues, temperatures dropped quickly when placed in a cold environment.

"Even though their brain was sending the right signals to turn on the heat, the mice were unable to defend their body temperature," Galmozzi says. "Without heme, you get mitochondrial dysfunction and the cell has no means to burn energy to generate heat."

Saez believes it's possible that activating the heme chaperone in other organs -- including the liver, where a large amount of heme is made -- could help mitigate the effects of other metabolic disorders such as non-alcoholic steatohepatitis (NASH), which is a major cause of liver transplantation today.

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Exoplanet axis study boosts hopes of complex life, just not next door

"They're out there," goes a saying about extraterrestrials. It would seem more likely to be true in light of a new study on planetary axis tilts.

Astrophysicists at the Georgia Institute of Technology modeled a theoretical twin of Earth into other star systems called binary systems because they have two stars. They concluded that 87% of exo-Earths one might find in binary systems should have axis tilts similarly steady to Earth's, an important ingredient for climate stability that favors the evolution of complex life.

"Multiple-star systems are common, and about 50% of stars have binary companion stars. So, this study can be applied to a large number of solar systems," said Gongjie Li, the study's co-investigator an assistant professor at Georgia Tech's School of Physics.

Single-star solar systems like our own with multiple planets appear to be rarer.

Alpha Centauri B? Wretched

The researchers started out contrasting how the Earth's axis tilt, also called obliquity, varies over time with the variation of Mars' axis tilt. Whereas our planet's mild obliquity variations have been great for a livable climate and for evolution, the wild variations of Mars' axis tilt may have helped wreck its atmosphere, as explained in the section below.

Then the researchers modeled Earth into habitable, or Goldilocks, zones in Alpha Centauri AB -- our solar system's nearest neighbor, a binary system with one star called "A" and the other "B." After that, they expanded the model to a more universal scope.

"We simulated what it would be like around other binaries with multiple variations of the stars' masses, orbital qualities, and so on," said Billy Quarles, the study's principal investigator and a research scientist in Li's lab. "The overall message was positive but not for our nearest neighbor."

Alpha Centauri A actually didn't look bad, but the outlook for mild axis dynamics on an exo-Earth modeled around star B was wretched. This may douse some hopes because Alpha Centauri AB is four lightyears away, and a mission named Starshot with big-name backers plans to launch a space probe to look for signs of advanced life there.

The researchers are publishing their study, which was co-led by Jack Lissauer from NASA Ames Research Center, in Astrophysical Journal on November 19, 2019, under the title: "Obliquity Evolution of Circumstellar Planets in Sun-like Stellar Binaries." The research was funded by the NASA Exobiology Program.

No exoplanets have been confirmed around A or B; an exoplanet has been confirmed around the nearby red dwarf star Proxima Centauri, but it is very likely to be uninhabitable.

Earth? Just right

Even with its ice ages and hot phases, Earth's climatological framework has been calm for hundreds of millions of years -- in part because of its mild orbital and axis-tilt dynamics -- allowing evolution to take big strides. Wildly varying dynamics, and thus climate, like on Mars would stand to regularly kill off advanced life, stunting evolution.

Earth's orbit around the sun is on a slight incline that seesaws gently and very slowly through a slight precession, a kind of oscillation. As Earth revolves, it shifts position relative to the sun, circling it a little like a spirograph drawing. The orbit also precesses in shape between slightly more and slightly less oblong over 100,000-year periods.

Earth's axis tilt precesses between 22.1 and 24.5 degrees over the course of 41,000 years. Our large moon stabilizes our tilt through its gravitational relationship with Earth, otherwise, bouncy gravitational interconnections with Mercury, Venus, Mars, and Jupiter would jolt our tilt with resonances.

"If we didn't have the moon, Earth's tilt could vary by about 60 degrees," Quarles said. "We'd look maybe like Mars, and the precession of its axis appears to have helped deplete its atmosphere."

Mars' axis precesses between 10 degrees and 60 degrees every 2 million years. At the 10-degree tilt, the atmosphere condenses at the poles, creating caps that lock up a lot of the atmosphere in ice. At 60 degrees, Mars could grow an ice belt around its equator.

Universe? Hopeful

In Alpha Centauri AB, star B, about the size of our sun, and the larger star, A, orbit one another at about the distance between Uranus and our sun, which is a very close for two stars in a binary system. The study modeled variations of an exo-Earth orbiting either star but concentrated on a modeled Earth orbit in the habitable zone centered around B, with A being the orbiting star.

A's orbit is very elliptical, passing close by and then moving very far away from B and slinging powerful gravity, which, in the model, overpowered exo-Earth's own dynamics. Its tilt and orbit varied widely; adding our moon to the model didn't help.

"Around Alpha Centauri B, if you don't have a moon, you have a more stable axis than if you do have a moon. If you have a moon, it's pretty much bad news," Quarles said.

Even without a moon and with mild axis variability, complex, Earthlike evolution would seem to have a hard time on the modeled exo-Earth around B.

"The biggest effect you would see is differences in the climate cycles related to how elongated the orbit is. Instead of having ice ages every 100,000 years like on Earth, they may come every 1 million years, be worse, and last much longer," Quarles said.

But a sliver of hope for Earthlike conditions turned up in the model: "Planetary orbit and spin need to precess just right relative to the binary orbit. There is this tiny sweet spot," Quarles said.

When the researchers expanded the model to binary systems in the universe, the probability of gentle obliquity variations ballooned.

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Outback telescope captures Milky Way center, discovers remnants of dead stars

A radio telescope in the Western Australian outback has captured a spectacular new view of the centre of the galaxy in which we live, the Milky Way.

The image from the Murchison Widefield Array (MWA) telescope shows what our galaxy would look like if human eyes could see radio waves.

Astrophysicist Dr Natasha Hurley-Walker, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), created the images using the Pawsey Supercomputing Centre in Perth.

"This new view captures low-frequency radio emission from our galaxy, looking both in fine detail and at larger structures," she said.

"Our images are looking directly at the middle of the Milky Way, towards a region astronomers call the Galactic Centre."

The data for the research comes from the GaLactic and Extragalactic All-sky MWA survey, or 'GLEAM' for short.

The survey has a resolution of two arcminutes (about the same as the human eye) and maps the sky using radio waves at frequencies between 72 and 231 MHz (FM radio is near 100 MHz).

"It's the power of this wide frequency range that makes it possible for us to disentangle different overlapping objects as we look toward the complexity of the Galactic Centre," Dr Hurley-Walker said.

"Essentially, different objects have different 'radio colours', so we can use them to work out what kind of physics is at play."

Using the images, Dr Hurley-Walker and her colleagues discovered the remnants of 27 massive stars that exploded in supernovae at the end of their lives.

These stars would have been eight or more times more massive than our Sun before their dramatic destruction thousands of years ago.

Younger and closer supernova remnants, or those in very dense environments, are easy to spot, and 295 are already known.

Unlike other instruments, the MWA can find those which are older, further away, or in very empty environments.

Dr Hurley-Walker said one of the newly-discovered supernova remnants lies in such an empty region of space, far out of the plane of our galaxy, and so despite being quite young, is also very faint.

"It's the remains of a star that died less than 9,000 years ago, meaning the explosion could have been visible to Indigenous people across Australia at that time," she said.

An expert in cultural astronomy, Associate Professor Duane Hamacher from the University of Melbourne, said some Aboriginal traditions do describe bright new stars appearing in the sky, but we don't know of any definitive traditions that describe this particular event.

"However, now that we know when and where this supernova appeared in the sky, we can collaborate with Indigenous elders to see if any of their traditions describe this cosmic event. If any exist, it would be extremely exciting," he said.

Dr Hurley-Walker said two of the supernova remnants discovered are quite unusual "orphans," found in a region of sky where there are no massive stars, which means future searches across other such regions might be more successful than astronomers expected.

Other supernova remnants discovered in the research are very old, she said.

"This is really exciting for us, because it's hard to find supernova remnants in this phase of life -- they allow us to look further back in time in the Milky Way."

The MWA telescope is a precursor to the world's largest radio telescope, the Square Kilometre Array, which is due to be built in Australia and South Africa from 2021.

"The MWA is perfect for finding these objects, but it is limited in its sensitivity and resolution," Dr Hurley-Walker said.

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Wind more effective than cold air at cooling rooms naturally

The effectiveness of non-mechanical, low-energy methods for moderating temperature and humidity has been evaluated in a series of experiments by researchers from the University of Cambridge.

The researchers found that a temperature difference between inside and outside has a remarkably small effect on how well a room is ventilated when ventilation is primarily driven by wind. In contrast, wind can increase ventilation rates by as much as 40% above that which is driven by a temperature difference between a room and the outdoors. The exact rate of ventilation will depend on the geometry of the room.

The results, reported in the journal Building and Environment, could be used to help designers and urban planners incorporate natural ventilation principles into their designs, so that buildings can be kept at a comfortable temperature while using less energy.

Heating and cooling account for a significant proportion of energy use in buildings: in the US, this is as high as 50 percent. In addition, as global temperatures continue to rise, demand for air conditioning -- which emits greenhouse gases -- rises as well, creating a damaging feedback loop.

Natural ventilation, which controls indoor temperature without using any mechanical systems, is an alternative to traditional heating and cooling methods, which reduces energy use and greenhouse gas emissions.

"Natural ventilation is a low-energy way to keep buildings at a comfortable temperature, but in order to increase its use, we need simple, accurate models that can respond quickly to changing conditions," said lead author Dr Megan Davies Wykes from Cambridge's Department of Engineering.

There are two main types of natural cross-ventilation: wind-driven and buoyancy-driven. Cross-ventilation occurs in rooms that have windows on opposite sides of a room. Wind blowing on a building can result in a high pressure on the windward side and a low pressure at the leeward side, which drives flow across a room, bringing fresh air in from outside and ventilating a room. Ventilation can also be driven by temperature differences between the inside and outside of a room, as incoming air is heated by people or equipment, resulting in a buoyancy-driven flow at a window.

"We've all gotten used to having a well-controlled, narrow temperature range in our homes and offices," said Davies Wykes. "Controlling natural ventilation methods is much more challenging than switching on the heat or the air conditioning, as you need to account for all the variables in a room, like the number of people, the number of computers or other heat-generating equipment, or the strength of the wind."

In the current study, the researchers used a miniature model room placed inside a flume to recreate the movements of air inside a room when windows are opened in different temperature and wind conditions.

Using the results from lab-based experiments, Davies Wykes and her colleagues built mathematical models to predict how temperature difference between inside and outside affects how well a room is ventilated.

The researchers found that the rate of ventilation depends less on temperature and more on wind. Anyone who has tried to cool down on a hot night by opening the window will no doubt be familiar with how ineffective this is when there is no wind.

This is because in many rooms, windows are positioned halfway up the wall, and when they are opened, the warm air near the ceiling can't easily escape. Without the 'mixing' effect provided by the wind, the warm air will stay at the ceiling, unless there is another way for it to escape at the top of the room.

"It was surprising that although temperature differences do not have a strong effect on the flow of air through a window, even small temperature differences can matter when trying to ventilate a room," said Davies Wykes. "If there are no openings near the ceiling of a room, warm indoor air can become trapped near the ceiling and wind is not effective at removing the trapped air."

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Beauty in the biased eye of the beholder

When we pass through an art gallery, what determines our idea of beauty? A University of Sydney study of how people rate the aesthetics of each artwork shows part of our aesthetic assessment is due to the painting you saw a few moments before.

The research, led by PhD student Ms Sujin Kim in the School of Psychology, is published in the Journal of Vision. It shows that we don't appreciate every painting in isolation. Instead, we carry a bias from the artwork just seen.

This bias is not the contrast effect you might intuitively think. A beautiful painting does not make the next one look less attractive but makes it more attractive.

The study, completed under the supervision of Professor David Alais from the University of Sydney and Professor David Burr from the University of Florence, Italy, involved presenting a sequence of 40 paintings to 24 observers who were asked to rate each one using a slider to indicate how aesthetically appealing or attractive it was. The paintings were depicting scenery or still life.

"While it is often said that beauty is in the eye of the beholder, this is not the whole story -- it partly depends on what was recently seen," Professor Alais said.

The first question the 24 observers were asked to respond to was whether they rated each painting independently of what they had just seen. To do this, the sequence was presented 20 times with each run having a different random order. In this way, a given painting was rated 20 times, but with a different random sequence preceding it. The data was clear: observers don't rate each painting consistently but are biased by what they just saw.

"Many people naively suppose a kind of 'contrast effect' whereby a painting may look more attractive if it follows an unattractive painting," Professor Alais said. "The surprising result was that the bias was a positive one: paintings were rated higher following an attractive painting, or lower, following unattractive ones."

The research refers to this effect as "serial dependence," which describes a systemic bias towards recent past experience. Previous studies have found, many stimulus attributes -- including orientation, numerosity, facial expression and attractiveness, and perceived slimness -- are systematically biased towards recent past experience. "Perhaps art curators have known all along about the bias towards the recent past," Professor Alais said. "They often keep the best pieces for last and build up to it. Our study shows this would ensure an accumulating effect and guarantee a big finish."

From Science Daily

Not so selfish after all -- Key role of transposable elements in mammalian evolution

The human genome contains 4.5 million copies of transposable elements (TEs), so-called selfish DNA sequences capable of moving around the genome through cut-and-paste or copy-and-paste mechanisms. Accounting for 30-50% of all of the DNA in the average mammalian genome, these TEs have conventionally been viewed as genetic freeloaders, hitchhiking along in the genome without providing any benefit to the host organism. More recently, however, scientists have begun to uncover cases in which TE sequences have been co-opted by the host to provide a useful function, such as encoding part of a host protein. In a new study published in the journal Nucleic Acids Research, Professor Hidenori Nishihara has undertaken one of the most comprehensive analyses of TE sequence co-option to date, uncovering tens of thousands of potentially co-opted TE sequences and suggesting that they have played a key role in mammalian evolution.

"I was specifically interested in the potential influence of TE sequences on the evolution of the mammary gland," notes Dr. Nishihara, "an organ that is responsible for producing milk and is, as the name suggests, a key distinguishing feature of mammals." To identify potentially co-opted TE sequences, Dr. Nishihara used four proteins -- ER?, FoxA1, GATA3, and AP2? -- that bind to DNA to regulate the production of proteins involved in mammary gland development. Dr. Nishihara then located all of the DNA sequences in the genome to which these proteins bind. Surprisingly, 20-30% of all of the binding sites across the genome were located in TEs, with as many as 38,500 TEs containing at least one binding site. The majority of these were in a copy-and-paste type of TE known as a retrotransposon, which duplicates itself, leaving a new copy in a new location.

The TE-derived binding site sequences were more conserved across species than expected, indicating that they are being preserved by evolution because they serve some important function. Dr. Nishihara believes that these TE sequences have been co-opted to serve as enhancers, DNA elements that increase the transcription of nearby genes. By binding to one of the four master regulators of mammary gland development, these enhancers ultimately increase the production of proteins involved in mammary gland development.

Dr. Nishihara then investigated when in mammalian evolution these TE sequences were acquired and found two distinct phases of acquisition: roughly 60-70% were acquired in the ancestor of all placental mammals (Eutheria), while 10-20% could be traced back to the ancestor of New World monkeys (Simiiformes). In addition, there appeared to be another wave of acquisition of ER? binding sites in the ancestor of mice and rats (Muridae). Thus, by providing a vast number of potential regulatory element binding sites throughout the genome, TEs may have had a substantial impact on the emergence of the mammary gland and its evolution within mammals.

Dr. Nishihara's study sheds light on the deep involvement of TEs in the evolution of mammary gland regulatory elements. However, it remains unclear how common this mode of TE-mediated regulatory network evolution is. Dr. Nishihara, at least, believes that the mammary gland is not unique in this respect. He notes that, "in addition to mammary glands, mammals share many features, such as the neocortex, closed secondary palate, and hair. I expect future research to uncover many additional kinds of TEs that have been similarly involved in the evolution of these features in mammals."

From Science Daily

Scientists find evidence of missing neutron star

The leftovers from a spectacular supernova that revolutionised our understanding of how stars end their lives have finally been spotted by astronomers at Cardiff University.

The scientists claim to have found evidence of the location of a neutron star that was left behind when a massive star ended its life in a gigantic explosion, leading to a famous supernova dubbed Supernova 1987A.

For more than 30 years astronomers have been unable to locate the neutron star -- the collapsed leftover core of the giant star -- as it has been concealed by a thick cloud of cosmic dust.

Using extremely sharp and sensitive images taken with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the Atacama Desert of northern Chile, the team have found a particular patch of the dust cloud that is brighter than its surroundings, and which matches the suspected location of the neutron star.

The findings have been published in The Astrophysical Journal.

Lead author of the study Dr Phil Cigan, from Cardiff University's School of Physics and Astronomy, said: "For the very first time we can tell that there is a neutron star inside this cloud within the supernova remnant. Its light has been veiled by a very thick cloud of dust, blocking the direct light from the neutron star at many wavelengths like fog masking a spotlight."

Dr Mikako Matsuura, another leading member of the study, added: "Although the light from the neutron star is absorbed by the dust cloud that surrounds it, this in turn makes the cloud shine in sub-millimetre light, which we can now see with the extremely sensitive ALMA telescope."

Supernova 1987A was first spotted by astronomers on Feb 23, 1987, when it blazed in the night sky with the power of 100 million suns, and continuing to shine brightly for several months.

The supernova was discovered in a neighbouring galaxy, the Large Magellanic Cloud, only 160,000 light years away.

It was the nearest supernova explosion observed in over 400 years and, since its discovery, has continued to fascinate astronomers who have been presented with the perfect opportunity to study the phases before, during, and after the death of a star.

The supernova explosion that took place at the end of this star's life resulted in huge amounts of gas with a temperature of over a million degrees, but as the gas began to cool down quickly below zero degrees centigrade, some of the gas transformed into a solid, i.e. dust.

The presence of this thick cloud of dust has long been the main explanation as to why the missing neutron star has not been observed, but many astronomers were sceptical about this and began to question whether their understanding of a star's life was correct.

"Our new findings will now enable astronomers to better understand how massive stars end their lives, leaving behind these extremely dense neutron stars," continued Dr Matsuura.

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Get over it? When it comes to recycled water, consumers won't

If people are educated on recycled water, they may come to agree it's perfectly safe and tastes as good -- or better -- than their drinking water. They may even agree it's an answer to the critical water imbalance in California, where the northern third of the state holds 75% of the water despite 80% of the demand coming from the southern two-thirds.

But that doesn't mean they're going to use recycled water -- and it sure doesn't mean they'll drink it. And the reason lies in the word "disgust."

That's the result of a series of studies by UC Riverside psychology researchers Mary Gauvain and Daniel Harmon published recently in the journal Basic and Applied Social Psychology.

Past research by Harmon and Gauvain explored whether people sense a difference in taste among recycled water, conventional tap water, and commercially bottled water. That study, released in spring 2018, was based on a blind taste test and found people actually preferred the taste of recycled water over conventional tap water.

However, "The idea of recycled wastewater in general evokes disgust reactions," Harmon said at the time.

This idea was addressed in the psychologists' latest research. If people disgusted by the notion of recycled wastewater are educated on its safety and benefits, will their attitudes change? And, will they change their behaviors?

In the research paper, "disgust" is defined as "a strong repulsion to a potentially harmful substance." In addition to disgust, the research considered other factors that dissuade people from using recycled water. Those included misinformation, ignorance, and peoples' desire to conform to social norms.

The research involved three separate studies and a total of 886 participants.

In study one, half of the subjects viewed a brief, pro-conservation internet video. The other group watched a short video about water, but not conservation, about the urban myth that crocodiles live in the sewer system of New York City.

Researchers found both groups failed to budge in their willingness to endorse sustainable water. Ninety-six percent of participants cited disgust as the reason. Distilling the reasoning even more, the researchers asked if participants were motivated by cleanliness or fear of illness. Sixty-five percent said cleanliness.

In study two, the videos were used again. But this time, an educational video demonstrating recycled wastewater is contaminant-free was also shown to address the disgust reaction. The pro-conservation and disgust videos had a "small but unsubstantial effect on peoples' willingness to use recycled wastewater" the research found.

In the last study, participants viewed all three videos. But this time, after completing a post-video survey, they were offered a bottle of water labeled "SMARTdrop -- Pure Recycled Water" and asked to sign a conservation petition.

Researchers hypothesized participants who watched the video addressing disgust would be more likely to accept the water and sign the petition. In fact, a similar number across all three groups -- about two-thirds -- took the water bottle and signed the petition.

The results of the three studies run counter to previous findings that assert media information can influence peoples' water conservation attitudes. Instead, they show internet messages may encourage people to view water sustainability more positively, but they do not encourage more sustainable water behaviors.

The article drawn from the research, "Influence of Internet-Based Messages and Personal Motivations on Water-Use Decisions," discourages using pro-recycled wastewater internet videos about water scarcity and conservation alone. Instead, researchers urge a focus on the more visceral roadblock of disgust. As an example, the researchers suggest a video stressing the extent of water purification in recycling plants as part of larger campaigns to change behaviors.

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