Astronomers have used mysterious fast radio bursts to solve a decades-old mystery of 'missing matter', long predicted to exist in the Universe but never detected -- until now.
The researchers have now found all of the missing 'normal' matter in the vast space between stars and galaxies, as detailed today in the journal Nature.
Lead author Associate Professor Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said astronomers have been searching for the missing matter for almost thirty years.
"We know from measurements of the Big Bang how much matter there was in the beginning of the Universe," he said.
"But when we looked out into the present Universe, we couldn't find half of what should be there. It was a bit of an embarrassment."
"Intergalactic space is very sparse," he said. "The missing matter was equivalent to only one or two atoms in a room the size of an average office."
"So it was very hard to detect this matter using traditional techniques and telescopes."
The researchers were able to directly detect the missing matter using the phenomenon known as fast radio bursts -- brief flashes of energy that appear to come from random directions in the sky and last for just milliseconds.
Scientists don't yet know what causes them but it must involve incredible energy, equivalent to the amount released by the Sun in 80 years. They have been difficult to detect as astronomers don't know when and where to look for them.
Associate Professor Macquart said the team detected the missing matter by using fast radio bursts as "cosmic weigh stations."
"The radiation from fast radio bursts gets spread out by the missing matter in the same way that you see the colours of sunlight being separated in a prism," he said.
"We've now been able to measure the distances to enough fast radio bursts to determine the density of the Universe," he said. "We only needed six to find this missing matter."
The missing matter in this case is baryonic or 'normal' matter -- like the protons and neutrons that make up stars, planets and you and me.
It's different from dark matter, which remains elusive and accounts for about 85 per cent of the total matter in the Universe.
Co-author Professor J. Xavier Prochaska, from UC Santa Cruz, said we have unsuccessfully searched for this missing matter with our largest telescopes for more than 20 years.
"The discovery of fast radio bursts and their localisation to distant galaxies were the key breakthroughs needed to solve this mystery," he said.
Associate Professor Ryan Shannon, another co-author from Swinburne University of Technology, said the key was the telescope used, CSIRO's Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope.
"ASKAP both has a wide field of view, about 60 times the size of the full Moon, and can image in high resolution," he said. "This means that we can catch the bursts with relative ease and then pinpoint locations to their host galaxies with incredible precision.
"When the burst arrives at the telescope, it records a live action replay within a fraction of a second," said Dr Keith Bannister from Australia's national science agency, CSIRO, who designed the pulse capture system used in this research.
"This enables the precision to determine the location of the fast radio burst to the width of a human hair held 200m away," he said.
Associate Professor Macquart said the research team had also pinned down the relationship between how far away a fast radio burst is and how the burst spreads out as it travels through the Universe.
"We've discovered the equivalent of the Hubble-Lemaitre Law for galaxies, only for fast radio bursts," he said.
"The Hubble-Lemaitre Law, which says the more distant a galaxy from us, the faster it is moving away from us, underpins all measurements of galaxies at cosmological distances."
The fast radio bursts used in the study were discovered using ASKAP, which is located at the Murchison Radio-astronomy Observatory in outback Western Australia. The international team involved in the discovery included astronomers from Australia, the United States and Chile.
Read more at Science Daily
May 30, 2020
Yes, your dog wants to rescue you
What to do. You're a dog. Your owner is trapped in a box and is crying out for help. Are you aware of his despair? If so, can you set him free? And what's more, do you really want to?
That's what Joshua Van Bourg and Clive Wynne wanted to know when they gave dogs the chance to rescue their owners.
Until recently, little research has been done on dogs' interest in rescuing humans, but that's what humans have come to expect from their canine companions -- a legend dating back to Lassie and updated by the popular Bolt.
"It's a pervasive legend," said Van Bourg, a graduate student in Arizona State University's Department of Psychology.
Simply observing dogs rescuing someone doesn't tell you much, Van Bourg said. "The difficult challenge is figuring out why they do it."
So, Van Bourg and Wynne, an ASU professor of psychology and director of the Canine Science Collaboratory at ASU, set up an experiment assessing 60 pet dogs' propensity to rescue their owners. None of the dogs had training in such an endeavor.
In the main test, each owner was confined to a large box equipped with a light-weight door, which the dog could move aside. The owners feigned distress by calling out "help," or "help me."
Beforehand, the researchers coached the owners so their cries for help sounded authentic. In addition, owners weren't allowed to call their dog's name, which would encourage the dog to act out of obedience, and not out of concern for her owner's welfare.
"About one-third of the dogs rescued their distressed owner, which doesn't sound too impressive on its own, but really is impressive when you take a closer look," Van Bourg said.
That's because two things are at stake here. One is the dogs' desire to help their owners, and the other is how well the dogs understood the nature of the help that was needed. Van Bourg and Wynne explored this factor in control tests -- tests that were lacking in previous studies.
In one control test, when the dog watched a researcher drop food into the box, only 19 of the 60 dogs opened the box to get the food. More dogs rescued their owners than retrieved food.
"The key here is that without controlling for each dog's understanding of how to open the box, the proportion of dogs who rescued their owners greatly underestimates the proportion of dogs who wanted to rescue their owners," Van Bourg said.
"The fact that two-thirds of the dogs didn't even open the box for food is a pretty strong indication that rescuing requires more than just motivation, there's something else involved, and that's the ability component," Van Bourg said. "If you look at only those 19 dogs that showed us they were able to open the door in the food test, 84% of them rescued their owners. So, most dogs want to rescue you, but they need to know how."
In another control test, Van Bourg and Wynne looked at what happened when the owner sat inside the box and calmly read aloud from a magazine. What they found was that four fewer dogs, 16 out of 60, opened the box in the reading test than in the distress test.
"A lot of the time it isn't necessarily about rescuing," Van Bourg said. "But that doesn't take anything away from how special dogs really are. Most dogs would run into a burning building just because they can't stand to be apart from their owners. How sweet is that? And if they know you're in distress, well, that just ups the ante."
The fact that dogs did open the box more often in the distress test than in the reading control test indicated that rescuing could not be explained solely by the dogs wanting to be near their owners.
The researchers also observed each dog's behavior during the three scenarios. They noted behaviors that can indicate stress, such as whining, walking, barking and yawning.
"During the distress test, the dogs were much more stressed," Van Bourg said. "When their owner was distressed, they barked more, and they whined more. In fact, there were eight dogs who whined, and they did so during the distress test. Only one other dog whined, and that was for food."
What's more, the second and third attempts to open the box during the distress test didn't make the dogs less stressed than they were during the first attempt. That was in contrast to the reading test, where dogs that have already been exposed to the scenario, were less stressed across repeated tests.
"They became acclimated," Van Bourg said. "Something about the owner's distress counteracts this acclimation. There's something about the owner calling for help that makes the dogs not get calmer with repeated exposure."
In essence, these individual behaviors are more evidence of "emotional contagion," the transmission of stress from the owner to the dog, explains Van Bourg, or what humans would call empathy.
"What's fascinating about this study," Wynne said, "is that it shows that dogs really care about their people. Even without training, many dogs will try and rescue people who appear to be in distress -- and when they fail, we can still see how upset they are. The results from the control tests indicate that dogs who fail to rescue their people are unable to understand what to do -- it's not that they don't care about their people.
Read more at Science Daily
That's what Joshua Van Bourg and Clive Wynne wanted to know when they gave dogs the chance to rescue their owners.
Until recently, little research has been done on dogs' interest in rescuing humans, but that's what humans have come to expect from their canine companions -- a legend dating back to Lassie and updated by the popular Bolt.
"It's a pervasive legend," said Van Bourg, a graduate student in Arizona State University's Department of Psychology.
Simply observing dogs rescuing someone doesn't tell you much, Van Bourg said. "The difficult challenge is figuring out why they do it."
So, Van Bourg and Wynne, an ASU professor of psychology and director of the Canine Science Collaboratory at ASU, set up an experiment assessing 60 pet dogs' propensity to rescue their owners. None of the dogs had training in such an endeavor.
In the main test, each owner was confined to a large box equipped with a light-weight door, which the dog could move aside. The owners feigned distress by calling out "help," or "help me."
Beforehand, the researchers coached the owners so their cries for help sounded authentic. In addition, owners weren't allowed to call their dog's name, which would encourage the dog to act out of obedience, and not out of concern for her owner's welfare.
"About one-third of the dogs rescued their distressed owner, which doesn't sound too impressive on its own, but really is impressive when you take a closer look," Van Bourg said.
That's because two things are at stake here. One is the dogs' desire to help their owners, and the other is how well the dogs understood the nature of the help that was needed. Van Bourg and Wynne explored this factor in control tests -- tests that were lacking in previous studies.
In one control test, when the dog watched a researcher drop food into the box, only 19 of the 60 dogs opened the box to get the food. More dogs rescued their owners than retrieved food.
"The key here is that without controlling for each dog's understanding of how to open the box, the proportion of dogs who rescued their owners greatly underestimates the proportion of dogs who wanted to rescue their owners," Van Bourg said.
"The fact that two-thirds of the dogs didn't even open the box for food is a pretty strong indication that rescuing requires more than just motivation, there's something else involved, and that's the ability component," Van Bourg said. "If you look at only those 19 dogs that showed us they were able to open the door in the food test, 84% of them rescued their owners. So, most dogs want to rescue you, but they need to know how."
In another control test, Van Bourg and Wynne looked at what happened when the owner sat inside the box and calmly read aloud from a magazine. What they found was that four fewer dogs, 16 out of 60, opened the box in the reading test than in the distress test.
"A lot of the time it isn't necessarily about rescuing," Van Bourg said. "But that doesn't take anything away from how special dogs really are. Most dogs would run into a burning building just because they can't stand to be apart from their owners. How sweet is that? And if they know you're in distress, well, that just ups the ante."
The fact that dogs did open the box more often in the distress test than in the reading control test indicated that rescuing could not be explained solely by the dogs wanting to be near their owners.
The researchers also observed each dog's behavior during the three scenarios. They noted behaviors that can indicate stress, such as whining, walking, barking and yawning.
"During the distress test, the dogs were much more stressed," Van Bourg said. "When their owner was distressed, they barked more, and they whined more. In fact, there were eight dogs who whined, and they did so during the distress test. Only one other dog whined, and that was for food."
What's more, the second and third attempts to open the box during the distress test didn't make the dogs less stressed than they were during the first attempt. That was in contrast to the reading test, where dogs that have already been exposed to the scenario, were less stressed across repeated tests.
"They became acclimated," Van Bourg said. "Something about the owner's distress counteracts this acclimation. There's something about the owner calling for help that makes the dogs not get calmer with repeated exposure."
In essence, these individual behaviors are more evidence of "emotional contagion," the transmission of stress from the owner to the dog, explains Van Bourg, or what humans would call empathy.
"What's fascinating about this study," Wynne said, "is that it shows that dogs really care about their people. Even without training, many dogs will try and rescue people who appear to be in distress -- and when they fail, we can still see how upset they are. The results from the control tests indicate that dogs who fail to rescue their people are unable to understand what to do -- it's not that they don't care about their people.
Read more at Science Daily
May 29, 2020
ESPRESSO confirms the presence of an Earth around the nearest star
The existence of a planet the size of Earth around the closest star in the solar system, Proxima Centauri, has been confirmed by an international team of scientists including researchers from the University of Geneva (UNIGE). The results, which you can read all about in the journal Astronomy & Astrophysics, reveal that the planet in question, Proxima b, has a mass of 1.17 earth masses and is located in the habitable zone of its star, which it orbits in 11.2 days. This breakthrough has been possible thanks to radial velocity measurements of unprecedented precision using ESPRESSO, the Swiss-manufactured spectrograph -- the most accurate currently in operation -- which is installed on the Very Large Telescope in Chile. Proxima b was first detected four years ago by means of an older spectrograph, HARPS -- also developed by the Geneva-based team -- which measured a low disturbance in the star's speed, suggesting the presence of a companion.
The ESPRESSO spectrograph has performed radial velocity measurements on the star Proxima Centauri, which is only 4.2 light-years from the Sun, with an accuracy of 30 centimetres a second (cm/s) or about three times more precise than that obtained with HARPS, the same type of instrument but from the previous generation.
"We were already very happy with the performance of HARPS, which has been responsible for discovering hundreds of exoplanets over the last 17 years," begins Francesco Pepe, a professor in the Astronomy Department in UNIGE's Faculty of Science and the man in charge of ESPRESSO. "We're really pleased that ESPRESSO can produce even better measurements, and it's gratifying and just reward for the teamwork lasting nearly 10 years."
Alejandro Suarez Mascareño, the article's main author, adds: "Confirming the existence of Proxima b was an important task, and it's one of the most interesting planets known in the solar neighbourhood."
The measurements performed by ESPRESSO have clarified that the minimum mass of Proxima b is 1.17 earth masses (the previous estimate was 1.3) and that it orbits around its star in only 11.2 days.
"ESPRESSO has made it possible to measure the mass of the planet with a precision of over one-tenth of the mass of Earth," says Michel Mayor, winner of the Nobel Prize for Physics in 2019, honorary professor in the Faculty of Science and the 'architect' of all ESPRESSO-type instruments. "It's completely unheard of."
And what about life in all this?
Although Proxima b is about 20 times closer to its star than the Earth is to the Sun, it receives comparable energy, so that its surface temperature could mean that water (if there is any) is in liquid form in places and might, therefore, harbour life.
Having said that, although Proxima b is an ideal candidate for biomarker research, there is still a long way to go before we can suggest that life has been able to develop on its surface. In fact, the Proxima star is an active red dwarf that bombards its planet with X rays, receiving about 400 times more than the Earth.
"Is there an atmosphere that protects the planet from these deadly rays?" asks Christophe Lovis, a researcher in UNIGE's Astronomy Department and responsible for ESPRESSO's scientific performance and data processing. "And if this atmosphere exists, does it contain the chemical elements that promote the development of life (oxygen, for example)? How long have these favourable conditions existed? We're going to tackle all these questions, especially with the help of future instruments like the RISTRETTO spectrometer, which we're going to build specially to detect the light emitted by Proxima b, and HIRES, which will be installed on the future ELT 39 m giant telescope that the European Southern Observatory (ESO) is building in Chile."
Surprise: is there a second planet?
In the meantime, the precision of the measurements made by ESPRESSO could result in another surprise. The team has found evidence of a second signal in the data, without being able to establish the definitive cause behind it. "If the signal was planetary in origin, this potential other planet accompanying Proxima b would have a mass less than one third of the mass of the Earth. It would then be the smallest planet ever measured using the radial velocity method," adds Professor Pepe.
Read more at Science Daily
The ESPRESSO spectrograph has performed radial velocity measurements on the star Proxima Centauri, which is only 4.2 light-years from the Sun, with an accuracy of 30 centimetres a second (cm/s) or about three times more precise than that obtained with HARPS, the same type of instrument but from the previous generation.
"We were already very happy with the performance of HARPS, which has been responsible for discovering hundreds of exoplanets over the last 17 years," begins Francesco Pepe, a professor in the Astronomy Department in UNIGE's Faculty of Science and the man in charge of ESPRESSO. "We're really pleased that ESPRESSO can produce even better measurements, and it's gratifying and just reward for the teamwork lasting nearly 10 years."
Alejandro Suarez Mascareño, the article's main author, adds: "Confirming the existence of Proxima b was an important task, and it's one of the most interesting planets known in the solar neighbourhood."
The measurements performed by ESPRESSO have clarified that the minimum mass of Proxima b is 1.17 earth masses (the previous estimate was 1.3) and that it orbits around its star in only 11.2 days.
"ESPRESSO has made it possible to measure the mass of the planet with a precision of over one-tenth of the mass of Earth," says Michel Mayor, winner of the Nobel Prize for Physics in 2019, honorary professor in the Faculty of Science and the 'architect' of all ESPRESSO-type instruments. "It's completely unheard of."
And what about life in all this?
Although Proxima b is about 20 times closer to its star than the Earth is to the Sun, it receives comparable energy, so that its surface temperature could mean that water (if there is any) is in liquid form in places and might, therefore, harbour life.
Having said that, although Proxima b is an ideal candidate for biomarker research, there is still a long way to go before we can suggest that life has been able to develop on its surface. In fact, the Proxima star is an active red dwarf that bombards its planet with X rays, receiving about 400 times more than the Earth.
"Is there an atmosphere that protects the planet from these deadly rays?" asks Christophe Lovis, a researcher in UNIGE's Astronomy Department and responsible for ESPRESSO's scientific performance and data processing. "And if this atmosphere exists, does it contain the chemical elements that promote the development of life (oxygen, for example)? How long have these favourable conditions existed? We're going to tackle all these questions, especially with the help of future instruments like the RISTRETTO spectrometer, which we're going to build specially to detect the light emitted by Proxima b, and HIRES, which will be installed on the future ELT 39 m giant telescope that the European Southern Observatory (ESO) is building in Chile."
Surprise: is there a second planet?
In the meantime, the precision of the measurements made by ESPRESSO could result in another surprise. The team has found evidence of a second signal in the data, without being able to establish the definitive cause behind it. "If the signal was planetary in origin, this potential other planet accompanying Proxima b would have a mass less than one third of the mass of the Earth. It would then be the smallest planet ever measured using the radial velocity method," adds Professor Pepe.
Read more at Science Daily
In planet formation, it's location, location, location
Astronomers using NASA's Hubble Space Telescope are finding that planets have a tough time forming in the rough-and-tumble central region of the massive, crowded star cluster Westerlund 2. Located 20,000 light-years away, Westerlund 2 is a unique laboratory to study stellar evolutionary processes because it's relatively nearby, quite young, and contains a large stellar population.
A three-year Hubble study of stars in Westerlund 2 revealed that the precursors to planet-forming disks encircling stars near the cluster's center are mysteriously devoid of large, dense clouds of dust that in a few million years could become planets.
However, the observations show that stars on the cluster's periphery do have the immense planet-forming dust clouds embedded in their disks. Researchers think our solar system followed this recipe when it formed 4.6 billion years ago.
So why do some stars in Westerlund 2 have a difficult time forming planets while others do not? It seems that planet formation depends on location, location, location. The most massive and brightest stars in the cluster congregate in the core, which is verified by observations of other star-forming regions. The cluster's center contains at least 30 extremely massive stars, some weighing up to 80 times the mass of the Sun. Their blistering ultraviolet radiation and hurricane-like stellar winds of charged particles blowtorch disks around neighboring lower-mass stars, dispersing the giant dust clouds.
"Basically, if you have monster stars, their energy is going to alter the properties of the disks around nearby, less massive stars," explained Elena Sabbi, of the Space Telescope Science Institute in Baltimore and lead researcher of the Hubble study. "You may still have a disk, but the stars change the composition of the dust in the disks, so it's harder to create stable structures that will eventually lead to planets. We think the dust either evaporates away in 1 million years, or it changes in composition and size so dramatically that planets don't have the building blocks to form."
The Hubble observations represent the first time that astronomers analyzed an extremely dense star cluster to study which environments are favorable to planet formation. Scientists, however, are still debating whether bulky stars are born in the center or whether they migrate there. Westerlund 2 already has massive stars in its core, even though it is a comparatively young, 2-million-year-old system.
Using Hubble's Wide Field Camera 3, the researchers found that of the nearly 5,000 stars in Westerlund 2 with masses between 0.1 to 5 times the Sun's mass, 1,500 of them show fluctuations in their light as the stars accrete material from their disks. Orbiting material clumped within the disk would temporarily block some of the starlight, causing brightness fluctuations.
However, Hubble detected the signature of such orbiting material only around stars outside the cluster's packed central region. The telescope witnessed large drops in brightness for as much as 10 to 20 days around 5% of the stars before they returned to normal brightness. They did not detect these dips in brightness in stars residing within four light-years of the center. These fluctuations could be caused by large clumps of dust passing in front of the star. The clumps would be in a disk tilted nearly edge-on to the view from Earth. "We think they are planetesimals or structures in formation," Sabbi explained. "These could be the seeds that eventually lead to planets in more evolved systems. These are the systems we don't see close to very massive stars. We see them only in systems outside the center."
Thanks to Hubble, astronomers can now see how stars are accreting in environments that are like the early universe, where clusters were dominated by monster stars. So far, the best known nearby stellar environment that contains massive stars is the starbirth region in the Orion Nebula. However, Westerlund 2 is a richer target because of its larger stellar population.
"Hubble's observations of Westerlund 2 give us a much better sense of how stars of different masses change over time, and how powerful winds and radiation from very massive stars affect nearby lower-mass stars and their disks," Sabbi said. "We see, for example, that lower-mass stars, like our Sun, that are near extremely massive stars in the cluster still have disks and still can accrete material as they grow. But the structure of their disks (and thus their planet-forming capability) seems to be very different from that of disks around stars forming in a calmer environment farther away from the cluster core. This information is important for building models of planet formation and stellar evolution."
This cluster will be an excellent laboratory for follow-up observations with NASA's upcoming James Webb Space Telescope, an infrared observatory. Hubble has helped astronomers identify the stars that have possible planetary structures. With Webb, researchers can study which disks around stars are not accreting material and which disks still have material that could build up into planets. This information on 1,500 stars will allow astronomers to map a path on how star systems grow and evolve. Webb also can study the chemistry of the disks in different evolutionary phases and watch how they change, and help astronomers determine what influence environment plays in their evolution.
Read more at Science Daily
A three-year Hubble study of stars in Westerlund 2 revealed that the precursors to planet-forming disks encircling stars near the cluster's center are mysteriously devoid of large, dense clouds of dust that in a few million years could become planets.
However, the observations show that stars on the cluster's periphery do have the immense planet-forming dust clouds embedded in their disks. Researchers think our solar system followed this recipe when it formed 4.6 billion years ago.
So why do some stars in Westerlund 2 have a difficult time forming planets while others do not? It seems that planet formation depends on location, location, location. The most massive and brightest stars in the cluster congregate in the core, which is verified by observations of other star-forming regions. The cluster's center contains at least 30 extremely massive stars, some weighing up to 80 times the mass of the Sun. Their blistering ultraviolet radiation and hurricane-like stellar winds of charged particles blowtorch disks around neighboring lower-mass stars, dispersing the giant dust clouds.
"Basically, if you have monster stars, their energy is going to alter the properties of the disks around nearby, less massive stars," explained Elena Sabbi, of the Space Telescope Science Institute in Baltimore and lead researcher of the Hubble study. "You may still have a disk, but the stars change the composition of the dust in the disks, so it's harder to create stable structures that will eventually lead to planets. We think the dust either evaporates away in 1 million years, or it changes in composition and size so dramatically that planets don't have the building blocks to form."
The Hubble observations represent the first time that astronomers analyzed an extremely dense star cluster to study which environments are favorable to planet formation. Scientists, however, are still debating whether bulky stars are born in the center or whether they migrate there. Westerlund 2 already has massive stars in its core, even though it is a comparatively young, 2-million-year-old system.
Using Hubble's Wide Field Camera 3, the researchers found that of the nearly 5,000 stars in Westerlund 2 with masses between 0.1 to 5 times the Sun's mass, 1,500 of them show fluctuations in their light as the stars accrete material from their disks. Orbiting material clumped within the disk would temporarily block some of the starlight, causing brightness fluctuations.
However, Hubble detected the signature of such orbiting material only around stars outside the cluster's packed central region. The telescope witnessed large drops in brightness for as much as 10 to 20 days around 5% of the stars before they returned to normal brightness. They did not detect these dips in brightness in stars residing within four light-years of the center. These fluctuations could be caused by large clumps of dust passing in front of the star. The clumps would be in a disk tilted nearly edge-on to the view from Earth. "We think they are planetesimals or structures in formation," Sabbi explained. "These could be the seeds that eventually lead to planets in more evolved systems. These are the systems we don't see close to very massive stars. We see them only in systems outside the center."
Thanks to Hubble, astronomers can now see how stars are accreting in environments that are like the early universe, where clusters were dominated by monster stars. So far, the best known nearby stellar environment that contains massive stars is the starbirth region in the Orion Nebula. However, Westerlund 2 is a richer target because of its larger stellar population.
"Hubble's observations of Westerlund 2 give us a much better sense of how stars of different masses change over time, and how powerful winds and radiation from very massive stars affect nearby lower-mass stars and their disks," Sabbi said. "We see, for example, that lower-mass stars, like our Sun, that are near extremely massive stars in the cluster still have disks and still can accrete material as they grow. But the structure of their disks (and thus their planet-forming capability) seems to be very different from that of disks around stars forming in a calmer environment farther away from the cluster core. This information is important for building models of planet formation and stellar evolution."
This cluster will be an excellent laboratory for follow-up observations with NASA's upcoming James Webb Space Telescope, an infrared observatory. Hubble has helped astronomers identify the stars that have possible planetary structures. With Webb, researchers can study which disks around stars are not accreting material and which disks still have material that could build up into planets. This information on 1,500 stars will allow astronomers to map a path on how star systems grow and evolve. Webb also can study the chemistry of the disks in different evolutionary phases and watch how they change, and help astronomers determine what influence environment plays in their evolution.
Read more at Science Daily
Children's temperament traits affect their motor skills
A recent study among 3- to 7-year-old children showed that children's motor skills benefitted if a child was older and participated in organised sports. Additionally, the study provided information about the importance of temperament traits for motor skills. More specifically, traits such as activity and attention span persistence were found to be positively associated with motor skills. This was a rather novel result, as the association between motor skills and temperament during early childhood is not yet widely understood.
In essence, motor skills comprise locomotor, ball and balance skills, all of which are present in everyday life tasks like running, climbing, throwing and drawing. Adequate motor skills enable participation in typical games and types of playing for different ages and developmental phases, for example, in tag, running and ball games.
"Even though motor skills develop as a function of age, skill development still needs to be stimulated consciously," says Donna Niemistö, a PhD student from the Faculty of Sport and Health Sciences, University of Jyväskylä. "Motor skills do not develop without practising, thus skills need reinforcement through repetition of the skills. Motor skill development is greatly supported when the child is moving in multiple ways. In a current study we found more evidence that participation in organised sports can be useful to gain more opportunities to practise and repeat essential movements."
Temperament and its traits refer to a child's biological and individual characteristics, such as the biological way of reacting to one's surroundings. Temperament is rather stable over time. To date, there have been only a handful of studies concerning young children's motor skills and temperament traits, even though in older age groups, more research is already available.
"Children who tend to have an active type of temperament, as well as children who show persistency when faced with challenges can be motivated and persistent in learning and rehearsing motor tasks. Therefore, these findings were expected and logical. A child with an active temperament can react more rapidly. Consequently, the child will get more opportunities to move along with increased repetitions. Without noticing, the child will also gain more opportunities to perform motor tasks."
Additionally, the capacity to maintain attention is equally important for skill acquisition.
"To learn new skills, one must be able to concentrate and maintain focus even though the skill may, at first, feel challenging or even difficult," continues Niemistö.
Both temperament traits can influence the development of motor skills. Therefore, it is important that parents as well as early educators and teachers are aware of these individual factors in case they want to encourage and support their children's motor skill development.
"For example, there is no need to emphasize for an active child to be more active," Niemistö explains. "However, with an active child, a parent could guide the child to maintain focus and attention, despite possible distractions in the surroundings."
Motor skills were assessed with two internationally well-known measurements. The first assessment tool measured the locomotor and ball skills and the second one the balance and coordination skills of the child. As the chosen assessment tools measured divergent aspects of motor development, differences between associated factors related to motor skills were also found.
"The development of balance and coordination skills was better in those children who were described as more emotionally regulated," says Niemistö. "On the other hand, locomotor skills were better in children whose parents had higher educational level and the development of ball skills benefitted if children had free access to sport facilities in nearby surroundings."
Read more at Science Daily
In essence, motor skills comprise locomotor, ball and balance skills, all of which are present in everyday life tasks like running, climbing, throwing and drawing. Adequate motor skills enable participation in typical games and types of playing for different ages and developmental phases, for example, in tag, running and ball games.
"Even though motor skills develop as a function of age, skill development still needs to be stimulated consciously," says Donna Niemistö, a PhD student from the Faculty of Sport and Health Sciences, University of Jyväskylä. "Motor skills do not develop without practising, thus skills need reinforcement through repetition of the skills. Motor skill development is greatly supported when the child is moving in multiple ways. In a current study we found more evidence that participation in organised sports can be useful to gain more opportunities to practise and repeat essential movements."
Temperament and its traits refer to a child's biological and individual characteristics, such as the biological way of reacting to one's surroundings. Temperament is rather stable over time. To date, there have been only a handful of studies concerning young children's motor skills and temperament traits, even though in older age groups, more research is already available.
"Children who tend to have an active type of temperament, as well as children who show persistency when faced with challenges can be motivated and persistent in learning and rehearsing motor tasks. Therefore, these findings were expected and logical. A child with an active temperament can react more rapidly. Consequently, the child will get more opportunities to move along with increased repetitions. Without noticing, the child will also gain more opportunities to perform motor tasks."
Additionally, the capacity to maintain attention is equally important for skill acquisition.
"To learn new skills, one must be able to concentrate and maintain focus even though the skill may, at first, feel challenging or even difficult," continues Niemistö.
Both temperament traits can influence the development of motor skills. Therefore, it is important that parents as well as early educators and teachers are aware of these individual factors in case they want to encourage and support their children's motor skill development.
"For example, there is no need to emphasize for an active child to be more active," Niemistö explains. "However, with an active child, a parent could guide the child to maintain focus and attention, despite possible distractions in the surroundings."
Motor skills were assessed with two internationally well-known measurements. The first assessment tool measured the locomotor and ball skills and the second one the balance and coordination skills of the child. As the chosen assessment tools measured divergent aspects of motor development, differences between associated factors related to motor skills were also found.
"The development of balance and coordination skills was better in those children who were described as more emotionally regulated," says Niemistö. "On the other hand, locomotor skills were better in children whose parents had higher educational level and the development of ball skills benefitted if children had free access to sport facilities in nearby surroundings."
Read more at Science Daily
Survey identifies learning opportunities related to health impacts of climate change
An international survey of Global Consortium on Climate and Health Education (GCCHE) membership found that the majority of members -- health professions schools and programs, including medical, nursing, and public health -- offer learning opportunities related to the health impacts of climate change, yet many also encountered challenges in instituting or developing curricula. The results of the survey provide a baseline assessment of the state of climate-health education internationally among health professions institutions. Results of the survey by Columbia University Mailman School of Public Health researchers appear in the journal JAMA Network Open.
The survey suggests there exist a range of educational offerings on climate-health, including sessions, courses, programs, or post-doctoral positions. Some schools have offered climate-health education for several years, some are just now adding content, and others do not include any content on the subject. While many schools are discussing adding climate-health educational offerings, there are still considerable gaps in offerings at many institutions as well as challenges that extend beyond the institutional level, such as political and funding priorities that might lead to lack of staff time and materials to support the training.
Conducted in 2017 and 2018, the survey was completed by 84 health professions institutions internationally. Among respondents, 63% offer climate-health education, most commonly as part of a required core course (76%). Sixty-one of 82 respondents (74%) reported additional climate-health offerings are under discussion, 42 of 59 (71%) encountered some challenges trying to institute the curriculum, and most have received a positive response to adding content mainly from students (39 of 58 (67%)), faculty (35 of 58 (60%)), and administration (23 of 58 (40%)).
The article's authors write that opportunities exist to facilitate the integration of climate-health curricula, such as working with students, faculty, and members of administration that are interested in this topic. In order to facilitate this integration, institutions can look to online resources, groups, and networks to provide guidance and information to develop curricula.
"We suggest that health professions schools include this content in their curricula and that awareness as well as financial support, resources, and expertise increase to help in its uptake," write study authors Brittany Shea, MA, Kim Knowlton, DrPH, and Jeffrey Shaman, PhD. "Climate change may be affecting health in a variety of ways with increasing consequences. Health professionals, including those in public health, nursing, and medical services, should be educated on how to prevent, mitigate, and respond to factors associated with climate change that may be associated with health in a negative way."
Read more at Science Daily
The survey suggests there exist a range of educational offerings on climate-health, including sessions, courses, programs, or post-doctoral positions. Some schools have offered climate-health education for several years, some are just now adding content, and others do not include any content on the subject. While many schools are discussing adding climate-health educational offerings, there are still considerable gaps in offerings at many institutions as well as challenges that extend beyond the institutional level, such as political and funding priorities that might lead to lack of staff time and materials to support the training.
Conducted in 2017 and 2018, the survey was completed by 84 health professions institutions internationally. Among respondents, 63% offer climate-health education, most commonly as part of a required core course (76%). Sixty-one of 82 respondents (74%) reported additional climate-health offerings are under discussion, 42 of 59 (71%) encountered some challenges trying to institute the curriculum, and most have received a positive response to adding content mainly from students (39 of 58 (67%)), faculty (35 of 58 (60%)), and administration (23 of 58 (40%)).
The article's authors write that opportunities exist to facilitate the integration of climate-health curricula, such as working with students, faculty, and members of administration that are interested in this topic. In order to facilitate this integration, institutions can look to online resources, groups, and networks to provide guidance and information to develop curricula.
"We suggest that health professions schools include this content in their curricula and that awareness as well as financial support, resources, and expertise increase to help in its uptake," write study authors Brittany Shea, MA, Kim Knowlton, DrPH, and Jeffrey Shaman, PhD. "Climate change may be affecting health in a variety of ways with increasing consequences. Health professionals, including those in public health, nursing, and medical services, should be educated on how to prevent, mitigate, and respond to factors associated with climate change that may be associated with health in a negative way."
Read more at Science Daily
May 27, 2020
Clues to COVID-19 in the brain uncovered in new study
A study by University of Cincinnati researchers and four Italian institutions reviewing neuroimaging and neurological symptoms in patients with COVID-19 may shed light on the virus's impact on the central nervous system.
The findings, published in the journal Radiology, reveal that altered mental status and stroke are the most common neurological symptoms in COVID-19 patients, which authors say could help physicians notice "red flags" earlier.
"Studies have described the spectrum of chest imaging features of COVID-19, but only a few case reports have described COVID-19 associated neuroimaging findings," says lead author Abdelkader Mahammedi, MD, assistant professor of radiology at UC and a UC Health neuroradiologist. "To date, this is the largest and first study in literature that characterizes the neurological symptoms and neuroimaging features in COVID-19 patients. These newly discovered patterns could help doctors better and sooner recognize associations with COVID-19 and possibly provide earlier interventions."
Researchers in this study investigated neurological symptoms and imaging findings in patients from three major institutions in Italy: University of Brescia, Brescia; University of Eastern Piedmont, Novara; and University of Sassari, Sassari. Italy was the second epicenter of the spread of COVID-19, resulting in over 30,000 deaths.
The study included images from 725 hospitalized patients with confirmed COVID-19 infection between Feb. 29 and April 4. Of these, 108 (15%) had serious neurological symptoms and underwent brain or spine imaging. Most patients (99%) had brain CT scans, while 16% had head and neck CT imaging and 18% had brain MRI.
Investigators found that 59% of patients reported an altered mental state and 31% experienced stroke, which were the most common neurological symptoms. Patients also experienced headache (12%), seizure (9%) and dizziness (4%), among other symptoms.
"Of these 108 patients, 31, or 29%, had no known past medical history. Of these, aged 16 to 62 years, 10 experienced stroke and two had brain bleeds," Mahammedi says. "Seventy-one, or 66%, of these patients had no findings on a brain CT, out of which 7 of them (35%) brain MRI showed abnormalities."
He adds that altered mental status was more common in older adults.
While results show that the neuroimaging features of patients with COVID-19 vary, and an altered mental status and stroke are the most prevalent in patients, Mahammedi says this study reveals that there are other conditions to be on the lookout for.
Read more at Science Daily
The findings, published in the journal Radiology, reveal that altered mental status and stroke are the most common neurological symptoms in COVID-19 patients, which authors say could help physicians notice "red flags" earlier.
"Studies have described the spectrum of chest imaging features of COVID-19, but only a few case reports have described COVID-19 associated neuroimaging findings," says lead author Abdelkader Mahammedi, MD, assistant professor of radiology at UC and a UC Health neuroradiologist. "To date, this is the largest and first study in literature that characterizes the neurological symptoms and neuroimaging features in COVID-19 patients. These newly discovered patterns could help doctors better and sooner recognize associations with COVID-19 and possibly provide earlier interventions."
Researchers in this study investigated neurological symptoms and imaging findings in patients from three major institutions in Italy: University of Brescia, Brescia; University of Eastern Piedmont, Novara; and University of Sassari, Sassari. Italy was the second epicenter of the spread of COVID-19, resulting in over 30,000 deaths.
The study included images from 725 hospitalized patients with confirmed COVID-19 infection between Feb. 29 and April 4. Of these, 108 (15%) had serious neurological symptoms and underwent brain or spine imaging. Most patients (99%) had brain CT scans, while 16% had head and neck CT imaging and 18% had brain MRI.
Investigators found that 59% of patients reported an altered mental state and 31% experienced stroke, which were the most common neurological symptoms. Patients also experienced headache (12%), seizure (9%) and dizziness (4%), among other symptoms.
"Of these 108 patients, 31, or 29%, had no known past medical history. Of these, aged 16 to 62 years, 10 experienced stroke and two had brain bleeds," Mahammedi says. "Seventy-one, or 66%, of these patients had no findings on a brain CT, out of which 7 of them (35%) brain MRI showed abnormalities."
He adds that altered mental status was more common in older adults.
While results show that the neuroimaging features of patients with COVID-19 vary, and an altered mental status and stroke are the most prevalent in patients, Mahammedi says this study reveals that there are other conditions to be on the lookout for.
Read more at Science Daily
Children may not always grow out of being picky eaters
If your preschooler often pushes their dinner plate away or wages battles against taking another bite of a vegetable they don't like, they may not grow out of it anytime soon.
By age four, children could be established picky eaters, a new study suggests. And the more parents try to control and restrict children's diets, the more finicky they may become, according to findings published in Pediatrics.
"Picky eating is common during childhood and parents often hear that their children will eventually 'grow out of it.' But that's not always the case," says senior author Megan Pesch, M.D., a developmental behavioral pediatrician at Michigan Medicine C.S. Mott Children's Hospital.
But there's a silver lining for worried parents -- while fussy eaters have a lower body mass index, most are still in the healthy range and not underweight, researchers found. They may also be less likely to be overweight or experience obesity than peers.
"We still want parents to encourage varied diets at young ages, but our study suggests that they can take a less controlling approach," Pesch says. That being said "we need more research to better understand how children's limited food choices impact healthy weight gain and growth long term."
The study followed 317 mother-child pairs from low-income homes over a four-year period. Families reported on children's eating habits and mothers' behaviors and attitudes about feeding when children were four, five, six, eight and nine.
Picky eating was stable from preschool to school-age, indicating that any attempts to expand food preferences may need to occur in toddler or preschool years to be most effective. High picky eating was associated with lower BMIs and low picky eating was associated with higher BMIs.
The pickiest eaters also were often associated with increased pressure to eat and restriction on certain types of foods. This reinforces previous Mott-led research suggesting that pressuring children to eat foods they dislike won't lead to a well-rounded diet later in life or encourage better health or development.
Certain child characteristics, including sex, birth order, and socioeconomic status, also have been associated with persistence of picky eating.
"We found that children who were pickier had mothers who reported more restriction of unhealthy foods and sweets," Pesch says. "These mothers of picky eaters may be trying to shape their children's preferences for more palatable and selective diets to be more healthful. But it may not always have the desired effect."
Read more at Science Daily
By age four, children could be established picky eaters, a new study suggests. And the more parents try to control and restrict children's diets, the more finicky they may become, according to findings published in Pediatrics.
"Picky eating is common during childhood and parents often hear that their children will eventually 'grow out of it.' But that's not always the case," says senior author Megan Pesch, M.D., a developmental behavioral pediatrician at Michigan Medicine C.S. Mott Children's Hospital.
But there's a silver lining for worried parents -- while fussy eaters have a lower body mass index, most are still in the healthy range and not underweight, researchers found. They may also be less likely to be overweight or experience obesity than peers.
"We still want parents to encourage varied diets at young ages, but our study suggests that they can take a less controlling approach," Pesch says. That being said "we need more research to better understand how children's limited food choices impact healthy weight gain and growth long term."
The study followed 317 mother-child pairs from low-income homes over a four-year period. Families reported on children's eating habits and mothers' behaviors and attitudes about feeding when children were four, five, six, eight and nine.
Picky eating was stable from preschool to school-age, indicating that any attempts to expand food preferences may need to occur in toddler or preschool years to be most effective. High picky eating was associated with lower BMIs and low picky eating was associated with higher BMIs.
The pickiest eaters also were often associated with increased pressure to eat and restriction on certain types of foods. This reinforces previous Mott-led research suggesting that pressuring children to eat foods they dislike won't lead to a well-rounded diet later in life or encourage better health or development.
Certain child characteristics, including sex, birth order, and socioeconomic status, also have been associated with persistence of picky eating.
"We found that children who were pickier had mothers who reported more restriction of unhealthy foods and sweets," Pesch says. "These mothers of picky eaters may be trying to shape their children's preferences for more palatable and selective diets to be more healthful. But it may not always have the desired effect."
Read more at Science Daily
Genomic analysis in samples of Neanderthals and modern humans shows a decrease in ADHD-associated genetic variants
The frequency of genetic variants associated with attention-deficit/hyperactivity disorder (ADHD) has decreased progressively in the evolutionary human lineage from the Palaeolithic to the present day, according to a study published in the journal Scientific Reports.
The new genomic analysis compares several ADHD-associated genetic variants described in current European populations to assess its evolution in samples of the human species (Homo sapiens), modern and ancient, and in samples of Neanderthals (Homo neanderthalensis). According to the conclusions, the low tendency observed in European populations could not be explained for the genetic mix with African populations or the introgression of Neanderthal genomic segments in our genome.
The new genomic study isled by Professor Bru Cormand, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona (IBUB), the Research Institute Sant Joan de Déu (IRSJD) and the Rare Diseases Networking Biomedical Research Centre (CIBERER), and the researcher Oscar Lao, from the Centro Nacional de Análisis Genómico (CNAG), part of the Centre for Genomic Regulation (CRG). The study, whose first author is the CNAG-CRG researcher Paula Esteller -- current doctoral student at the Institute of Evolutionary Biology (IBE, CSIC-UPF) -- counts on the participation of research groups of the Aarhus University (Denmark) and the Upstate Medical University of New York (United States).
ADHD: an adaptive value in the evolutionary lineage of humans?
The attention deficit/hyperactivity disorder (ADHD) is an alteration of the neurodevelopment which can have a large impact on the life of the affected people. Featured by hyperactivity, impulsiveness and attention deficit, it is very common in modern populations -- with a prevalence of 5% in children and adolescents -- and can last up to adulthood.
From an evolutionary perspective, one would expect that anything detrimental would disappear among the population. In order to explain this phenomenon, several natural hypotheses have been presented, specifically focused on the context of transition from the Palaeolithic to the Neolithic, such as the known Mismatch Theory.
"According to this theory, cultural and technological changes that occurred over the last thousands of years would have allowed us to modify our environment in order to adopt it to our physiological needs in the short term. However, in the long term, these changes would have promoted an imbalance regarding the environment in which our hunter-gatherer ancestors evolved," note the authors.
Therefore, several traits like hyperactivity and impulsiveness -- typical in people with ADHD -- could have been selectively favoured in ancestral environments dominated by a nomad lifestyle. However, the same features would have become non-adaptive in other environments related to more recent times (mostly sedentary).
Why is it one of the most common disorders in children and adolescents?
The new study, based on the study on 20,000 ADHD affected people and 35,000 controls, reveals the genetic variants and alleles associated with ADHD tend to be found in genes which are intolerant to mutations that cause loss of function, which shows the existence of a selective pressure on this phenotype.
According to the authors, the high prevalence of ADHD nowadays could be a result from a favourable selection that took place in the past. Although being an unfavourable phenotype in the new environmental context, the prevalence would still be high because much time has not passed for it to disappear. However, due to the absence of available genomic data for ADHD, none of the hypothesis has been empirically contrasted so far.
Read more at Science Daily
The new genomic analysis compares several ADHD-associated genetic variants described in current European populations to assess its evolution in samples of the human species (Homo sapiens), modern and ancient, and in samples of Neanderthals (Homo neanderthalensis). According to the conclusions, the low tendency observed in European populations could not be explained for the genetic mix with African populations or the introgression of Neanderthal genomic segments in our genome.
The new genomic study isled by Professor Bru Cormand, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona (IBUB), the Research Institute Sant Joan de Déu (IRSJD) and the Rare Diseases Networking Biomedical Research Centre (CIBERER), and the researcher Oscar Lao, from the Centro Nacional de Análisis Genómico (CNAG), part of the Centre for Genomic Regulation (CRG). The study, whose first author is the CNAG-CRG researcher Paula Esteller -- current doctoral student at the Institute of Evolutionary Biology (IBE, CSIC-UPF) -- counts on the participation of research groups of the Aarhus University (Denmark) and the Upstate Medical University of New York (United States).
ADHD: an adaptive value in the evolutionary lineage of humans?
The attention deficit/hyperactivity disorder (ADHD) is an alteration of the neurodevelopment which can have a large impact on the life of the affected people. Featured by hyperactivity, impulsiveness and attention deficit, it is very common in modern populations -- with a prevalence of 5% in children and adolescents -- and can last up to adulthood.
From an evolutionary perspective, one would expect that anything detrimental would disappear among the population. In order to explain this phenomenon, several natural hypotheses have been presented, specifically focused on the context of transition from the Palaeolithic to the Neolithic, such as the known Mismatch Theory.
"According to this theory, cultural and technological changes that occurred over the last thousands of years would have allowed us to modify our environment in order to adopt it to our physiological needs in the short term. However, in the long term, these changes would have promoted an imbalance regarding the environment in which our hunter-gatherer ancestors evolved," note the authors.
Therefore, several traits like hyperactivity and impulsiveness -- typical in people with ADHD -- could have been selectively favoured in ancestral environments dominated by a nomad lifestyle. However, the same features would have become non-adaptive in other environments related to more recent times (mostly sedentary).
Why is it one of the most common disorders in children and adolescents?
The new study, based on the study on 20,000 ADHD affected people and 35,000 controls, reveals the genetic variants and alleles associated with ADHD tend to be found in genes which are intolerant to mutations that cause loss of function, which shows the existence of a selective pressure on this phenotype.
According to the authors, the high prevalence of ADHD nowadays could be a result from a favourable selection that took place in the past. Although being an unfavourable phenotype in the new environmental context, the prevalence would still be high because much time has not passed for it to disappear. However, due to the absence of available genomic data for ADHD, none of the hypothesis has been empirically contrasted so far.
Read more at Science Daily
Increased fertility for women with Neanderthal gene, study suggests
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| DNA abstract illustration |
"The progesterone receptor is an example of how favourable genetic variants that were introduced into modern humans by mixing with Neandertals can have effects in people living today," says Hugo Zeberg, researcher at the Department of Neuroscience at Karolinska Institutet and the Max Planck Institute for Evolutionary Anthropology, who performed the study with colleagues Janet Kelso and Svante Pääbo.
Progesterone is a hormone, which plays an important role in the menstrual cycle and in pregnancy. Analyses of biobank data from more than 450,000 participants -- among them 244,000 women -- show that almost one in three women in Europe have inherited the progesterone receptor from Neandertals. Twenty-nine percent carry one copy of the Neandertal receptor and three percent have two copies.
Favourable effect on fertility
"The proportion of women who inherited this gene is about ten times greater than for most Neandertal gene variants," says Hugo Zeberg. "These findings suggest that the Neandertal variant of the receptor has a favourable effect on fertility."
The study shows that women who carry the Neandertal variant of the receptor tend to have fewer bleedings during early pregnancy, fewer miscarriages, and give birth to more children. Molecular analyses revealed that these women produce more progesterone receptors in their cells, which may lead to increased sensitivity to progesterone and protection against early miscarriages and bleeding.
Read more at Science Daily
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