A single dose of a highly diluted VSV-Ebola virus (EBOV) vaccine -- approximately one-millionth of what is in the vaccine being used to help control the ongoing Ebola outbreak in the Democratic Republic of the Congo (DRC) -- remains fully protective against disease in experimentally infected monkeys, according to National Institutes of Health scientists. The NIH investigators completed the vaccine dosage study using cynomolgus macaques and an updated vaccine component to match the EBOV Makona strain that circulated in West Africa from 2014-16. The study appears in Lancet's EBioMedicine.
Nearly 250,000 people have received the investigational VSV-EBOV vaccine since August 2018 as part of a "ring vaccination" program to help stem the outbreak. The vaccine appears to be safe and highly effective. The manufacturer has announced that it has submitted a biologics license application to the U.S. Food and Drug Administration. VSV-EBOV is based on a live-attenuated vesicular stomatitis virus and delivers an EBOV protein to elicit protective immune responses. With the continued need to vaccinate individuals in the DRC and surrounding countries, a potential shortage of VSV-EBOV vaccine is a concern and further dose adjustment is a possible solution.
Scientists from NIH's Rocky Mountain Laboratories (RML), part of the National Institute of Allergy and Infectious Diseases, tested several dosage strengths, including one with 10 million plaque-forming units (PFU). They determined that a vaccine with 10 PFUs was just as effective as the highest dose tested (a dose which was still lower than the one currently in use in the DRC). They vaccinated macaques 28 days prior to infecting them with a lethal dose of EBOV and then monitored the animals for 42 days after infection. Even the macaques given the lowest dose appeared completely protected from disease due to EBOV.
The scientists say their study findings could help make more vaccine available for more people and may reduce adverse reactions to the vaccine because of the smaller amount of active ingredient. Such reactions can include injection site irritation, headache, fatigue, fever, chills, myalgia, and arthralgia. Demonstrating that the vaccine appears effective with adjusted dosing also could ease the burden on vaccine production.
The authors say that although results from preclinical and clinical studies can differ, these promising findings in macaques of complete protection with a lower-dose VSV-EBOV vaccine help support the possibility of similar clinical trials in people.
From Science Daily
Oct 19, 2019
A new discovery: How our memories stabilize while we sleep
Scientists at the Center for Interdisciplinary Research in Biology (CNRS/Collège de France/INSERM) have shown that delta waves emitted while we sleep are not generalized periods of silence during which the cortex rests, as has been described for decades in the scientific literature. Instead, they isolate assemblies of neurons that play an essential role in long-term memory formation. These results were published on 18 October 2019 in Science.
While we sleep, the hippocampus reactivates itself spontaneously by generating activity similar to that while we are awake. It sends information to the cortex, which reacts in turn. This exchange is often followed by a period of silence called a 'delta wave' then by rhythmic activity called a 'sleep spindle'. This is when the cortical circuits reorganize to form stable memories. However, the role of delta waves in the formation of new memories is still a puzzle: why does a period of silence interrupt the sequence of information exchanges between the hippocampus and the cortex, and the functional reorganisation of the cortex?
The authors here looked more closely at what happens during delta waves themselves. They discovered, surprisingly, that the cortex is not entirely silent but that a few neurons remain active and form assemblies, i.e. small, coactive sets that code information. This unexpected observation suggests that the small number of neurons that activate when all the others stay quiet can carry out important calculations while protected from possible disturbances. And the discoveries from this work go even further! Spontaneous reactivations of the hippocampus determine which cortical neurons remain active during the delta waves and reveal transmission of information between the two cerebral structures. In addition, the assemblies activated during the delta waves are formed of neurons that have participated in learning a spatial memory task during the day. Together these elements suggest that these processes are involved in memory consolidation. To demonstrate it, in rats the scientists caused artificial delta waves to isolate either neurons associated with reactivations in the hippocampus, or random neurons. Result: when the right neurons were isolated, the rats managed to stabilise their memories and succeed at the spatial test the next day.
These results substantially change how we understand the cortex. Delta waves are therefore a means of selectively isolating assemblies of chosen neurons, which send crucial information between the periods of hippocampo-cortical dialog and the reorganisation of cortical circuits, to form long-term memories.
From Science Daily
While we sleep, the hippocampus reactivates itself spontaneously by generating activity similar to that while we are awake. It sends information to the cortex, which reacts in turn. This exchange is often followed by a period of silence called a 'delta wave' then by rhythmic activity called a 'sleep spindle'. This is when the cortical circuits reorganize to form stable memories. However, the role of delta waves in the formation of new memories is still a puzzle: why does a period of silence interrupt the sequence of information exchanges between the hippocampus and the cortex, and the functional reorganisation of the cortex?
The authors here looked more closely at what happens during delta waves themselves. They discovered, surprisingly, that the cortex is not entirely silent but that a few neurons remain active and form assemblies, i.e. small, coactive sets that code information. This unexpected observation suggests that the small number of neurons that activate when all the others stay quiet can carry out important calculations while protected from possible disturbances. And the discoveries from this work go even further! Spontaneous reactivations of the hippocampus determine which cortical neurons remain active during the delta waves and reveal transmission of information between the two cerebral structures. In addition, the assemblies activated during the delta waves are formed of neurons that have participated in learning a spatial memory task during the day. Together these elements suggest that these processes are involved in memory consolidation. To demonstrate it, in rats the scientists caused artificial delta waves to isolate either neurons associated with reactivations in the hippocampus, or random neurons. Result: when the right neurons were isolated, the rats managed to stabilise their memories and succeed at the spatial test the next day.
These results substantially change how we understand the cortex. Delta waves are therefore a means of selectively isolating assemblies of chosen neurons, which send crucial information between the periods of hippocampo-cortical dialog and the reorganisation of cortical circuits, to form long-term memories.
From Science Daily
Oct 18, 2019
Lifestyle is a threat to gut bacteria: Ötzi proves it, study shows
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| Intestinal bacteria illustration |
The industrialization process in Western countries had a huge impact on its content. This was confirmed by a study on the bacteria found in the intestine of Ötzi, the Iceman who, in 1991, emerged from the ice of the Ötztal Alps, where Italy borders with Austria. Scientists of Eurac Research examined samples of the mummy's bacteria, confirming the findings of the researchers of the University of Trento who had analyzed the genome of intestinal microorganisms of over 6500 individuals from all continents.
Previous studies by the University of Trento had demonstrated that there is a connection between the microbiome's bacterial content and the increase, in Western countries, of obesity, autoimmune and gastrointestinal diseases, allergies and other complex conditions. In the study that appeared today in Cell Host & Microbe, researchers from Cibio of the University of Trento and Eurac in Bolzano/Bozen demonstrated that the differences between Western and non-Western or prehistoric microbiome lie in the decrease of some types of bacteria that process complex and vegetal fibers in the intestine.
That may have been caused by the Westernization process. Changes in diet, which is now higher in fat and low in fibers, a sedentary lifestyle in an urban setting, the development of new hygiene habits and the widespread use of antibiotics and other medical products have, with no doubt, made our life safer, but impacted the delicate balance of our microbiome.
About the study
The scientists of Eurac Research in Bolzano/Bozen sequenced the Iceman's DNA and were able to identify his set of bacteria, while the researchers of the University of Trento compared it with the microbiome of contemporary non-Westernized populations (from Tanzania and Ghana in particular), which are not used to processed food and have non-Westernized hygiene practices and lifestyle. Their findings were surprising.
The study focused, in particular, on Prevotella copri, a microbe that, when is found in our intestine, is usually the most represented. P. copri is present in 30% of Western individuals.
"First of all, we found out that P. copri it is not a monotypic species but is composed of four distinct but similar clades," explained Nicola Segata, coordinator of the study with Adrian Tett of Cibio of the University of Trento. "We then noticed that at least three of these four clades are almost always present in non-Westernized populations, but are much less prevalent in Westernized individuals. And when it is so, there usually is only one of the four clades. We postulated that the complex process of Westernization had a considerable impact on the gradual disappearance of this bacterium. Our hypothesis was confirmed by the analysis of ancient samples of DNA that were made available by Frank Maixner of the Institute for Mummy Studies at Eurac Research. The Iceman's guts contained three of the four clades of P. copri. And the four clades were also co-present in fossilized stool samples from Mexico that are more than one thousand years old. We still do not know what are the biomedical consequences of these changes of the microbiome which has evolved considerably in recent decades while the human body it colonizes has remained genetically practically unchanged for centuries,"
"Through these 'ancient' samples," continued Tett, "we were able to study the evolution of these clades and now we know that they genetically delineated with the human species and before the initial human migrations out of the African continent."
Read more at Science Daily
Ancient stars shed light on Earth's similarities to other planets
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| Exoplanets illustration; elements furnished by NASA. |
"We have just raised the probability that many rocky planets are like the Earth, and there's a very large number of rocky planets in the universe," said co-author Edward Young, UCLA professor of geochemistry and cosmochemistry.
The scientists, led by Alexandra Doyle, a UCLA graduate student of geochemistry and astrochemistry, developed a new method to analyze in detail the geochemistry of planets outside of our solar system. Doyle did so by analyzing the elements in rocks from asteroids or rocky planet fragments that orbited six white dwarf stars.
"We're studying geochemistry in rocks from other stars, which is almost unheard of," Young said.
"Learning the composition of planets outside our solar system is very difficult," said co-author Hilke Schlichting, UCLA associate professor of astrophysics and planetary science. "We used the only method possible -- a method we pioneered -- to determine the geochemistry of rocks outside of the solar system."
White dwarf stars are dense, burned-out remnants of normal stars. Their strong gravitational pull causes heavy elements like carbon, oxygen and nitrogen to sink rapidly into their interiors, where the heavy elements cannot be detected by telescopes. The closest white dwarf star Doyle studied is about 200 light-years from Earth and the farthest is 665 light-years away.
"By observing these white dwarfs and the elements present in their atmosphere, we are observing the elements that are in the body that orbited the white dwarf," Doyle said. The white dwarf's large gravitational pull shreds the asteroid or planet fragment that is orbiting it, and the material falls onto the white dwarf, she said. "Observing a white dwarf is like doing an autopsy on the contents of what it has gobbled in its solar system."
The data Doyle analyzed were collected by telescopes, mostly from the W.M. Keck Observatory in Hawaii, that space scientists had previously collected for other scientific purposes.
"If I were to just look at a white dwarf star, I would expect to see hydrogen and helium," Doyle said. "But in these data, I also see other materials, such as silicon, magnesium, carbon and oxygen -- material that accreted onto the white dwarfs from bodies that were orbiting them."
When iron is oxidized, it shares its electrons with oxygen, forming a chemical bond between them, Young said. "This is called oxidation, and you can see it when metal turns into rust," he said. "Oxygen steals electrons from iron, producing iron oxide rather than iron metal. We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. We studied how much the metal rusts."
Rocks from the Earth, Mars and elsewhere in our solar system are similar in their chemical composition and contain a surprisingly high level of oxidized iron, Young said. "We measured the amount of iron that got oxidized in these rocks that hit the white dwarf," he said.
The sun is made mostly of hydrogen, which does the opposite of oxidizing -- hydrogen adds electrons.
The researchers said the oxidation of a rocky planet has a significant effect on its atmosphere, its core and the kind of rocks it makes on its surface. "All the chemistry that happens on the surface of the Earth can ultimately be traced back to the oxidation state of the planet," Young said. "The fact that we have oceans and all the ingredients necessary for life can be traced back to the planet being oxidized as it is. The rocks control the chemistry."
Until now, scientists have not known in any detail whether the chemistry of rocky exoplanets is similar to or very different from that of the Earth.
How similar are the rocks the UCLA team analyzed to rocks from the Earth and Mars?
"Very similar," Doyle said. "They are Earth-like and Mars-like in terms of their oxidized iron. We're finding that rocks are rocks everywhere, with very similar geophysics and geochemistry."
"It's always been a mystery why the rocks in our solar system are so oxidized," Young said. "It's not what you expect. A question was whether this would also be true around other stars. Our study says yes. That bodes really well for looking for Earth-like planets in the universe."
White dwarf stars are a rare environment for scientists to analyze.
The researchers studied the six most common elements in rock: iron, oxygen, silicon, magnesium, calcium and aluminum. They used mathematical calculations and formulas because scientists are unable to study actual rocks from white dwarfs. "We can determine the geochemistry of these rocks mathematically and compare these calculations with rocks that we do have from Earth and Mars," said Doyle, whose background is in geology and mathematics. "Understanding the rocks is crucial because they reveal the geochemistry and geophysics of the planet."
"If extraterrestrial rocks have a similar quantity of oxidation as the Earth has, then you can conclude the planet has similar plate tectonics and similar potential for magnetic fields as the Earth, which are widely believed to be key ingredients for life," Schlichting said. "This study is a leap forward in being able to make these inferences for bodies outside our own solar system and indicates it's very likely there are truly Earth analogs."
Read more at Science Daily
Arthropods formed orderly lines 480 million years ago
Researchers studied fossilized Moroccan Ampyx trilobites, which lived 480 million years ago and showed that the trilobites had probably been buried in their positions -- all oriented in the same direction. Scientists deduced that these Ampyx processions may illustrate a kind of collective behavior adopted in response to cyclic environmental disturbances.
Though our understanding of the anatomy of the earliest animals is growing ever more precise, we know next to nothing about their behaviour. Did group behaviour arise recently or is it primeval? To answer this question, researchers from the CNRS, the University of Poitiers, UBO, Claude Bernard Lyon 1 University*, Cadi Ayyad University (Marrakech, Morocco), and the University of Lausanne (Switzerland) studied fossilized Moroccan Ampyx trilobites, which lived 480 million years ago. They showed that the trilobites had probably been buried in their positions -- all oriented in the same direction, in orderly lines, maintaining close contact with each other through their long spines -- during storms.
By comparing this observation with the behaviour of living animals such as North American spiny lobsters, the scientists deduced that these Ampyx processions may illustrate a similar kind of collective behaviour -- adopted in response to cyclic environmental disturbances like storms or to chemical signals associated with reproduction.
This example would seem to suggest that group behaviour is of ancient origin and, from an early date, likely conferred an evolutionary advantage on the first animals, allowing them to survive environmental stress and improve their reproductive chances.
*From the Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS / ENS de Lyon / Université Claude Bernard Lyon 1), the Laboratoire Géosciences Océan (CNRS / Université Bretagne Occidentale / Université Bretagne Sud), and the Institute of Chemistry of Materials and Media of Poitiers (IC2MP (CNRS / Université de Poitiers).
From Science Daily
Though our understanding of the anatomy of the earliest animals is growing ever more precise, we know next to nothing about their behaviour. Did group behaviour arise recently or is it primeval? To answer this question, researchers from the CNRS, the University of Poitiers, UBO, Claude Bernard Lyon 1 University*, Cadi Ayyad University (Marrakech, Morocco), and the University of Lausanne (Switzerland) studied fossilized Moroccan Ampyx trilobites, which lived 480 million years ago. They showed that the trilobites had probably been buried in their positions -- all oriented in the same direction, in orderly lines, maintaining close contact with each other through their long spines -- during storms.
By comparing this observation with the behaviour of living animals such as North American spiny lobsters, the scientists deduced that these Ampyx processions may illustrate a similar kind of collective behaviour -- adopted in response to cyclic environmental disturbances like storms or to chemical signals associated with reproduction.
This example would seem to suggest that group behaviour is of ancient origin and, from an early date, likely conferred an evolutionary advantage on the first animals, allowing them to survive environmental stress and improve their reproductive chances.
*From the Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS / ENS de Lyon / Université Claude Bernard Lyon 1), the Laboratoire Géosciences Océan (CNRS / Université Bretagne Occidentale / Université Bretagne Sud), and the Institute of Chemistry of Materials and Media of Poitiers (IC2MP (CNRS / Université de Poitiers).
From Science Daily
Daily exposure to blue light may accelerate aging, even if it doesn't reach your eyes
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| Woman looking at blue light from at computer screen. |
New research at Oregon State University suggests that the blue wavelengths produced by light-emitting diodes damage cells in the brain as well as retinas.
The study, published today in Aging and Mechanisms of Disease, involved a widely used organism, Drosophila melanogaster, the common fruit fly, an important model organism because of the cellular and developmental mechanisms it shares with other animals and humans.
Jaga Giebultowicz, a researcher in the OSU College of Science who studies biological clocks, led a research collaboration that examined how flies responded to daily 12-hour exposures to blue LED light -- similar to the prevalent blue wavelength in devices like phones and tablets -- and found that the light accelerated aging.
Flies subjected to daily cycles of 12 hours in light and 12 hours in darkness had shorter lives compared to flies kept in total darkness or those kept in light with the blue wavelengths filtered out. The flies exposed to blue light showed damage to their retinal cells and brain neurons and had impaired locomotion -- the flies' ability to climb the walls of their enclosures, a common behavior, was diminished.
Some of the flies in the experiment were mutants that do not develop eyes, and even those eyeless flies displayed brain damage and locomotion impairments, suggesting flies didn't have to see the light to be harmed by it.
"The fact that the light was accelerating aging in the flies was very surprising to us at first," said Giebultowicz, a professor of integrative biology. "We'd measured expression of some genes in old flies, and found that stress-response, protective genes were expressed if flies were kept in light. We hypothesized that light was regulating those genes. Then we started asking, what is it in the light that is harmful to them, and we looked at the spectrum of light. It was very clear cut that although light without blue slightly shortened their lifespan, just blue light alone shortened their lifespan very dramatically."
Natural light, Giebultowicz notes, is crucial for the body's circadian rhythm -- the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration that are important factors in feeding and sleeping patterns.
"But there is evidence suggesting that increased exposure to artificial light is a risk factor for sleep and circadian disorders," she said. "And with the prevalent use of LED lighting and device displays, humans are subjected to increasing amounts of light in the blue spectrum since commonly used LEDs emit a high fraction of blue light. But this technology, LED lighting, even in most developed countries, has not been used long enough to know its effects across the human lifespan."
Giebultowicz says that the flies, if given a choice, avoid blue light.
"We're going to test if the same signaling that causes them to escape blue light is involved in longevity," she said.
Eileen Chow, faculty research assistant in Giebultowicz's lab and co-first author of the study, notes that advances in technology and medicine could work together to address the damaging effects of light if this research eventually proves applicable to humans.
"Human lifespan has increased dramatically over the past century as we've found ways to treat diseases, and at the same time we have been spending more and more time with artificial light," she said. "As science looks for ways to help people be healthier as they live longer, designing a healthier spectrum of light might be a possibility, not just in terms of sleeping better but in terms of overall health."
In the meantime, there are a few things people can do to help themselves that don't involve sitting for hours in darkness, the researchers say. Eyeglasses with amber lenses will filter out the blue light and protect your retinas. And phones, laptops and other devices can be set to block blue emissions.
Read more at Science Daily
Oct 17, 2019
Phylogenetic analysis forces rethink of termite evolution
Despite their important ecological role as decomposers, termites are often overlooked in research. Evolutionary biologists at the Okinawa Institute of Science and Technology Graduate University (OIST) have constructed a new family tree for this unassuming insect brood, shedding unexpected light on its evolutionary history.
Writing in Current Biology, the team presents a new tree showing the relationship among termite families and subfamilies. Critically, they have managed to correctly place a subfamily of termites that has until now befuddled researchers. Through comprehensive analysis of termite RNA sequences, the team has now determined the proper position of termites within the Termitidae family.
The Termitidae make up around 80% of termite species and are important as decomposers. This is because, unlike in other families, many Termitidae have shifted their food source from wood to soil and decomposing plant matter -- an important change in diet that took place when they lost protist gut symbionts found in all other termite families. This loss was possibly triggered by new relationships with fungi and bacteria, which the Termitidae cultivate externally in complex sponge-like structures called combs.
The Sphaerotermitinae is one such comb-building subfamily. And while they have previously been difficult to place, the RNA analysis has confirmed that they are, in fact, a sister of the fungus growing Macrotermitinae subfamily -- within the Termitidae. Both subfamilies build combs inside their nests, and the new family tree explains how this behavior evolved.
"Cultivating fungi and bacteria in combs is a peculiar way of securing food," explains Dr. Aleš Bu?ek, a postdoctoral scholar in OIST's Evolutionary Genomics Unit. "It was previously thought that comb building led to the loss of protist gut symbionts in Termitidae. But the new family tree suggests that combs emerged in the ancestor of Sphaerotermitinae and Macrotermitinae -- not across the whole Termitidae family."
"It seems likely, therefore, that associations with new gut bacteria allowed for the loss of old symbionts."
Rethinking the termite family tree
When researchers construct a family tree, or phylogeny, they can do so using different genes. By looking at the differences in a gene between species, they can understand how closely-related those species are. Often, researchers construct a phylogeny using a single gene. This can, however, give an inaccurate picture of the relationship between species -- and can incorrectly place them.
Instead of relying on a single gene, the OIST team used up to 4065 genes from each termite species to construct the phylogeny. This provides a more reliable picture of how different species are related. They included 55 termite species from across the globe, representing all major lineages.
This tree indicated that the Sphaerotermitinae is, in fact, a sister of the comb building Macrotermitinae, a well-studied subfamily of termites. The two sisters both build combs, although only in the Macrotermitinae does this involve the cultivation of fungi for food. Sphaerotermitinae combs, meanwhile, appear to contain bacteria, although the species are not yet identified.
What the team can say, however, is that comb building emerged only once, several million years after the loss of gut symbionts in the ancestor of all Termitidae.
Read more at Science Daily
Writing in Current Biology, the team presents a new tree showing the relationship among termite families and subfamilies. Critically, they have managed to correctly place a subfamily of termites that has until now befuddled researchers. Through comprehensive analysis of termite RNA sequences, the team has now determined the proper position of termites within the Termitidae family.
The Termitidae make up around 80% of termite species and are important as decomposers. This is because, unlike in other families, many Termitidae have shifted their food source from wood to soil and decomposing plant matter -- an important change in diet that took place when they lost protist gut symbionts found in all other termite families. This loss was possibly triggered by new relationships with fungi and bacteria, which the Termitidae cultivate externally in complex sponge-like structures called combs.
The Sphaerotermitinae is one such comb-building subfamily. And while they have previously been difficult to place, the RNA analysis has confirmed that they are, in fact, a sister of the fungus growing Macrotermitinae subfamily -- within the Termitidae. Both subfamilies build combs inside their nests, and the new family tree explains how this behavior evolved.
"Cultivating fungi and bacteria in combs is a peculiar way of securing food," explains Dr. Aleš Bu?ek, a postdoctoral scholar in OIST's Evolutionary Genomics Unit. "It was previously thought that comb building led to the loss of protist gut symbionts in Termitidae. But the new family tree suggests that combs emerged in the ancestor of Sphaerotermitinae and Macrotermitinae -- not across the whole Termitidae family."
"It seems likely, therefore, that associations with new gut bacteria allowed for the loss of old symbionts."
Rethinking the termite family tree
When researchers construct a family tree, or phylogeny, they can do so using different genes. By looking at the differences in a gene between species, they can understand how closely-related those species are. Often, researchers construct a phylogeny using a single gene. This can, however, give an inaccurate picture of the relationship between species -- and can incorrectly place them.
Instead of relying on a single gene, the OIST team used up to 4065 genes from each termite species to construct the phylogeny. This provides a more reliable picture of how different species are related. They included 55 termite species from across the globe, representing all major lineages.
This tree indicated that the Sphaerotermitinae is, in fact, a sister of the comb building Macrotermitinae, a well-studied subfamily of termites. The two sisters both build combs, although only in the Macrotermitinae does this involve the cultivation of fungi for food. Sphaerotermitinae combs, meanwhile, appear to contain bacteria, although the species are not yet identified.
What the team can say, however, is that comb building emerged only once, several million years after the loss of gut symbionts in the ancestor of all Termitidae.
Read more at Science Daily
Surveying solar storms by ancient Assyrian astronomers
A research team led by the University of Tsukuba combined observations from ancient cuneiform tablets that mention unusual red skies with radioisotope data to identify solar storms that likely occurred around 679 to 655 BCE, prior to any previously datable events. This work may help modern astronomers predict future solar flares or coronal mass ejections that can damage satellite and terrestrial electronic devices.
Humans have been looking to the skies for as long as we have been around. Some of the observations made by ancient Assyrian and Babylonian astrologers more than two millennia ago survive in the form of cuneiform records. These rectangular clay tablets were messages from professional scholars to kings who had commissioned astronomical observations for the purpose of discerning omens -- including comets, meteors, and planetary motions.
Now, a team led by the University of Tsukuba has matched three of these ancient tablets that mention an unusual red glow in the sky with the carbon-14 concentrations in tree rings and demonstrate how they are evidence of solar magnetic storms. These observations were made approximately 2,700 years ago in Babylon and the Assyrian city of Nineveh, both of which are mentioned contemporaneously in the Bible. For example, one tablet says, "red covers the sky," while another mentions a "red cloud." These were probably manifestations of what we call today stable auroral red arcs, consisting of light emitted by electrons in atmospheric oxygen atoms after being excited by intense magnetic fields. While we usually think of aurorae as confined to northern latitudes, during periods of strong magnetic activity, as with a solar mass ejection, they may be observed much further south. Moreover, because of changes in the Earth's magnetic field over time, the Middle East was closer to the geomagnetic pole during this period in history.
"Although the exact dates of the observations are not known, we were able to narrow the range considerably by knowing when each astrologer was active," co-first author Yasuyuki Mitsuma says. Based on tree-ring samples, there was a rapid rise in radioactive carbon-14 in the environment during this time, which is associated with increased solar activity.
Read more at Science Daily
Humans have been looking to the skies for as long as we have been around. Some of the observations made by ancient Assyrian and Babylonian astrologers more than two millennia ago survive in the form of cuneiform records. These rectangular clay tablets were messages from professional scholars to kings who had commissioned astronomical observations for the purpose of discerning omens -- including comets, meteors, and planetary motions.
Now, a team led by the University of Tsukuba has matched three of these ancient tablets that mention an unusual red glow in the sky with the carbon-14 concentrations in tree rings and demonstrate how they are evidence of solar magnetic storms. These observations were made approximately 2,700 years ago in Babylon and the Assyrian city of Nineveh, both of which are mentioned contemporaneously in the Bible. For example, one tablet says, "red covers the sky," while another mentions a "red cloud." These were probably manifestations of what we call today stable auroral red arcs, consisting of light emitted by electrons in atmospheric oxygen atoms after being excited by intense magnetic fields. While we usually think of aurorae as confined to northern latitudes, during periods of strong magnetic activity, as with a solar mass ejection, they may be observed much further south. Moreover, because of changes in the Earth's magnetic field over time, the Middle East was closer to the geomagnetic pole during this period in history.
"Although the exact dates of the observations are not known, we were able to narrow the range considerably by knowing when each astrologer was active," co-first author Yasuyuki Mitsuma says. Based on tree-ring samples, there was a rapid rise in radioactive carbon-14 in the environment during this time, which is associated with increased solar activity.
Read more at Science Daily
Fundamental insight into how memory changes with age
New research from King's College London and The Open University could help explain why memory in old age is much less flexible than in young adulthood.
Through experiments in mice the researchers discovered that there were dramatic differences in how memories were stored in old age, compared to young adulthood. These differences, at the cellular level, meant that it was much harder to modify the memories made in old age.
Memories are stored in the brain by strengthening the connections between nerve cells, called synapses. Recalling a memory can alter these connections, allowing memories to be updated to adapt to a new situation. Until now researchers did not know whether this memory updating process was affected by age.
The researchers trained young adult and aged mice in a memory task, finding that the animals' age did not affect their overall ability to make new memories. However, when analysing the synapses before and after the memory task, the researchers found fundamental differences between older and younger mice.
New memories were laid down via a completely different mechanism in older animals compared to younger ones. Further, in older mice the synaptic changes linked to new memories were much harder to modify than the changes seen in younger mice.
The basic biological processes for laying down memories is shared by mammals, so it is likely that memory formation in humans follows the same processes discovered in mice.
Lead researcher Professor Karl Peter Giese, from the Institute of Psychiatry, Psychology & Neuroscience at King's, said: 'Our results give a fundamental insight into how memory processes change with age. We found that, unlike in the younger mice, memories in the older mice were not modified when recalled. This 'fixed' nature of memories formed in old age was directly linked to the alternative way the memories were laid down, which our research revealed.'
'Until now it was thought that older people should be able to form memories in just the same way as younger people, so overcoming memory problems would simply involve restoring this ability,' added Professor Giese. 'However, our results suggest this is not true, and that there is an important biological difference in how memories are stored in old age compared to young adulthood.'
The results may have implications for conditions where memory recall is a problem, such as post-traumatic stress disorder (PTSD). Professor Giese suggests that ageing should be taken into consideration when treating patients with PTSD, since confronting and modifying traumatic memories is a core feature of some psychological treatments such as trauma-focused cognitive behavioural therapy.
Read more at Science Daily
Through experiments in mice the researchers discovered that there were dramatic differences in how memories were stored in old age, compared to young adulthood. These differences, at the cellular level, meant that it was much harder to modify the memories made in old age.
Memories are stored in the brain by strengthening the connections between nerve cells, called synapses. Recalling a memory can alter these connections, allowing memories to be updated to adapt to a new situation. Until now researchers did not know whether this memory updating process was affected by age.
The researchers trained young adult and aged mice in a memory task, finding that the animals' age did not affect their overall ability to make new memories. However, when analysing the synapses before and after the memory task, the researchers found fundamental differences between older and younger mice.
New memories were laid down via a completely different mechanism in older animals compared to younger ones. Further, in older mice the synaptic changes linked to new memories were much harder to modify than the changes seen in younger mice.
The basic biological processes for laying down memories is shared by mammals, so it is likely that memory formation in humans follows the same processes discovered in mice.
Lead researcher Professor Karl Peter Giese, from the Institute of Psychiatry, Psychology & Neuroscience at King's, said: 'Our results give a fundamental insight into how memory processes change with age. We found that, unlike in the younger mice, memories in the older mice were not modified when recalled. This 'fixed' nature of memories formed in old age was directly linked to the alternative way the memories were laid down, which our research revealed.'
'Until now it was thought that older people should be able to form memories in just the same way as younger people, so overcoming memory problems would simply involve restoring this ability,' added Professor Giese. 'However, our results suggest this is not true, and that there is an important biological difference in how memories are stored in old age compared to young adulthood.'
The results may have implications for conditions where memory recall is a problem, such as post-traumatic stress disorder (PTSD). Professor Giese suggests that ageing should be taken into consideration when treating patients with PTSD, since confronting and modifying traumatic memories is a core feature of some psychological treatments such as trauma-focused cognitive behavioural therapy.
Read more at Science Daily
Scientists find early humans moved through Mediterranean earlier than believed
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| Map of Greek islands in the Aegean Sea showing Naxos in the center. |
The findings, published today in the journal Science Advances, are based on years of excavations and challenge current thinking about human movement in the region -- long thought to have been inaccessible and uninhabitable to anyone but modern humans. The new evidence is leading researchers to reconsider the routes our early ancestors took as they moved out of Africa into Europe and demonstrates their ability to adapt to new environmental challenges.
"Until recently, this part of the world was seen as irrelevant to early human studies but the results force us to completely rethink the history of the Mediterranean islands," says Tristan Carter, an associate professor of anthropology at McMaster University and lead author on the study. He conducted the work with Dimitris Athanasoulis, head of archaeology at the Cycladic Ephorate of Antiquities within the Greek Ministry of Culture.
While Stone Age hunters are known to have been living on mainland Europe for over 1 million years, the Mediterranean islands were previously believed to be settled only 9,000 years ago, by farmers, the idea being that only modern humans -- Homo sapiens -- were sophisticated enough to build seafaring vessels.
Scholars had believed the Aegean Sea, separating western Anatolia (modern Turkey) from continental Greece, was therefore impassable to the Neanderthals and earlier hominins, with the only obvious route in and out of Europe was across the land bridge of Thrace (southeast Balkans).
The authors of this paper suggest that the Aegean basin was in fact accessible much earlier than believed. At certain times of the Ice Age the sea was much lower exposing a land route between the continents that would have allowed early prehistoric populations to walk to Stelida, and an alternative migration route connecting Europe and Africa. Researchers believe the area would have been attractive to early humans because of its abundance of raw materials ideal for toolmaking and for its fresh water.
At the same time however, "in entering this region the pre-Neanderthal populations would have been faced with a new and challenging environment, with different animals, plants and diseases, all requiring new adaptive strategies," says Carter.
In this paper, the team details evidence of human activity spanning almost 200,000 years at Stelida, a prehistoric quarry on the northwest coast of Naxos. Here early Homo sapiens, Neanderthals and earlier humans used the local stone (chert) to make their tools and hunting weapons, of which the team has unearthed hundreds of thousands.
Reams of scientific data collected at the site add to the ongoing debate about the importance of coastal and marine routes to human movement. While present data suggests that the Aegean could be crossed by foot over 200,000 years ago, the authors also raise the possibility that Neanderthals may also have fashioned crude seafaring boats capable of crossing short distances.
Read more at Science Daily
Hubble observes first confirmed interstellar comet
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| Hubble photographed comet 2I/Borisov at a distance of 260 million miles from Earth. This Hubble image, taken on Oct. 12, 2019, is the sharpest view to date of the comet. Hubble reveals a central concentration of dust around the nucleus (which is too small to be seen by Hubble). The comet is falling toward the Sun and will make its closest approach on Dec. 7, 2019, when it will be twice as far from the Sun as Earth. The comet is following a hyperbolic path around the Sun and will exit back into interstellar space. |
This Hubble image, taken on Oct. 12, 2019, is the sharpest view of the comet to date. Hubble reveals a central concentration of dust around the nucleus (which is too small to be seen by Hubble).
Comet 2I/Borisov is only the second such interstellar object known to have passed through the solar system. In 2017, the first identified interstellar visitor, an object officially named 'Oumuamua, swung within 24 million miles of the Sun before racing out of the solar system. "Whereas 'Oumuamua appeared to be a rock, Borisov is really active, more like a normal comet. It's a puzzle why these two are so different," said David Jewitt of the University of California, Los Angeles (UCLA), leader of the Hubble team who observed the comet.
As the second known interstellar object found to enter our solar system, the comet provides invaluable clues to the chemical composition, structure and dust characteristics of planetary building blocks presumably forged in an alien star system a long time ago and far away.
"Though another star system could be quite different from our own, the fact that the comet's properties appear to be very similar to those of the solar system's building blocks is very remarkable," said Amaya Moro-Martin of the Space Telescope Science Institute in Baltimore.
Hubble photographed the comet at a distance of 260 million miles from Earth. The comet is falling past the Sun and will make its closest approach to the Sun on Dec. 7, 2019, when it will be twice as far from the Sun as Earth.
The comet is following a hyperbolic path around the Sun, and currently is blazing along at an extraordinary speed of 110,000 miles per hour. "It's traveling so fast it almost doesn't care that the Sun is there," said Jewitt.
By the middle of 2020 the comet will streak past Jupiter's distance of 500 million miles on its way back into interstellar space where it will drift for untold millions of years before skirting close to another star system.
Crimean amateur astronomer Gennady Borisov discovered the comet on Aug. 30, 2019. After a week of observations by amateur and professional astronomers all over the world, the International Astronomical Union's Minor Planet Center and the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory in Pasadena, California, computed a trajectory for the comet, which confirms that it came from interstellar space.
Until now, all cataloged comets have come from either a ring of icy debris at the periphery of our solar system, called the Kuiper belt, or the hypothetical Oort cloud, a shell of comets about a light-year from the Sun, defining the dynamical edge of our solar system.
Borisov and 'Oumuamua are only the beginning of the discoveries of interstellar objects paying a brief visit to our solar system, say researchers. According to one study there are thousands of such interlopers here at any given time, though most are too faint to be detected with current-day telescopes.
Observations by Hubble and other telescopes have shown that rings and shells of icy debris encircle young stars where planet formation is underway. A gravitational "pinball game" between these comet-like bodies or planets orbiting other stars can hurtle them deep into space where they go adrift among the stars.
Future Hubble observations of 2I/Borisov are planned through January 2020, with more being proposed.
Read more at Science Daily
Oct 16, 2019
Going against the flow around a supermassive black hole
At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas. When astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to study this cloud in more detail, they made an unexpected discovery that could explain why supermassive black holes grew so rapidly in the early Universe.
"Thanks to the spectacular resolution of ALMA, we measured the movement of gas in the inner orbits around the black hole," explains Violette Impellizzeri of the National Radio Astronomy Observatory (NRAO), working at ALMA in Chile and lead author on a paper published in the Astrophysical Journal. "Surprisingly, we found two disks of gas rotating in opposite directions."
Supermassive black holes already existed when the Universe was young -- just a billion years after the Big Bang. But how these extreme objects, whose masses are up to billions of times the mass of the Sun, had time to grow in such a relatively short timespan, is an outstanding question among astronomers. This new ALMA discovery could provide a clue. "Counter-rotating gas streams are unstable, which means that clouds fall into the black hole faster than they do in a disk with a single rotation direction," said Impellizzeri. "This could be a way in which a black hole can grow rapidly."
NGC 1068 (also known as Messier 77) is a spiral galaxy approximately 47 million light-years from Earth in the direction of the constellation Cetus. At its center is an active galactic nucleus, a supermassive black hole that is actively feeding itself from a thin, rotating disk of gas and dust, also known as an accretion disk.
Previous ALMA observations revealed that the black hole is not only gulping down material, but also spewing out gas at incredibly high speeds -- up to 500 kilometers per second (more than one million miles per hour). This gas that gets expelled from the accretion disk likely contributes to hiding the region around the black hole from optical telescopes.
Impellizzeri and her team used ALMA's superior zoom lens ability to observe the molecular gas around the black hole. Unexpectedly, they found two counter-rotating disks of gas. The inner disk spans 2-4 light-years and follows the rotation of the galaxy, whereas the outer disk (also known as the torus) spans 4-22 light-years and is rotating the opposite way.
"We did not expect to see this, because gas falling into a black hole would normally spin around it in only one direction," said Impellizzeri. "Something must have disturbed the flow, because it is impossible for a part of the disk to start rotating backward all on its own."
Counter-rotation is not an unusual phenomenon in space. "We see it in galaxies, usually thousands of light-years away from their galactic centers," explained co-author Jack Gallimore from Bucknell University in Lewisburg, Pennsylvania. "The counter-rotation always results from the collision or interaction between two galaxies. What makes this result remarkable is that we see it on a much smaller scale, tens of light-years instead of thousands from the central black hole."
The astronomers think that the backward flow in NGC 1068 might be caused by gas clouds that fell out of the host galaxy, or by a small passing galaxy on a counter-rotating orbit captured in the disk.
Read more at Science Daily
"Thanks to the spectacular resolution of ALMA, we measured the movement of gas in the inner orbits around the black hole," explains Violette Impellizzeri of the National Radio Astronomy Observatory (NRAO), working at ALMA in Chile and lead author on a paper published in the Astrophysical Journal. "Surprisingly, we found two disks of gas rotating in opposite directions."
Supermassive black holes already existed when the Universe was young -- just a billion years after the Big Bang. But how these extreme objects, whose masses are up to billions of times the mass of the Sun, had time to grow in such a relatively short timespan, is an outstanding question among astronomers. This new ALMA discovery could provide a clue. "Counter-rotating gas streams are unstable, which means that clouds fall into the black hole faster than they do in a disk with a single rotation direction," said Impellizzeri. "This could be a way in which a black hole can grow rapidly."
NGC 1068 (also known as Messier 77) is a spiral galaxy approximately 47 million light-years from Earth in the direction of the constellation Cetus. At its center is an active galactic nucleus, a supermassive black hole that is actively feeding itself from a thin, rotating disk of gas and dust, also known as an accretion disk.
Previous ALMA observations revealed that the black hole is not only gulping down material, but also spewing out gas at incredibly high speeds -- up to 500 kilometers per second (more than one million miles per hour). This gas that gets expelled from the accretion disk likely contributes to hiding the region around the black hole from optical telescopes.
Impellizzeri and her team used ALMA's superior zoom lens ability to observe the molecular gas around the black hole. Unexpectedly, they found two counter-rotating disks of gas. The inner disk spans 2-4 light-years and follows the rotation of the galaxy, whereas the outer disk (also known as the torus) spans 4-22 light-years and is rotating the opposite way.
"We did not expect to see this, because gas falling into a black hole would normally spin around it in only one direction," said Impellizzeri. "Something must have disturbed the flow, because it is impossible for a part of the disk to start rotating backward all on its own."
Counter-rotation is not an unusual phenomenon in space. "We see it in galaxies, usually thousands of light-years away from their galactic centers," explained co-author Jack Gallimore from Bucknell University in Lewisburg, Pennsylvania. "The counter-rotation always results from the collision or interaction between two galaxies. What makes this result remarkable is that we see it on a much smaller scale, tens of light-years instead of thousands from the central black hole."
The astronomers think that the backward flow in NGC 1068 might be caused by gas clouds that fell out of the host galaxy, or by a small passing galaxy on a counter-rotating orbit captured in the disk.
Read more at Science Daily
Gas 'waterfalls' reveal infant planets around young star
The birthplaces of planets are disks made out of gas and dust. Astronomers study these so-called protoplanetary disks to understand the processes of planet formation. Beautiful images of disks made with the Atacama Large Millimeter/submillimeter Array (ALMA) how distinct gaps and ring features in dust, which may be caused by infant planets.
To get more certainty that these gaps are actually caused by planets, and to get a more complete view of planet formation, scientists study the gas in the disks in addition to dust. 99 percent of a protoplanetary disk's mass is gas, of which carbon monoxide (CO) gas is the brightest component, emitting at a very distinctive millimeter-wavelength light that ALMA can observe.
Last year, two teams of astronomers demonstrated a new planet-hunting technique using this gas. They measured the velocity of CO gas rotating in the disk around the young star HD 163296. Localized disturbances in the movements of the gas revealed three planet-like patterns in the disk.
In this new study, lead author Richard Teague from the University of Michigan and his team used new high-resolution ALMA data from the Disk Substructures at High Angular Resolution Project (DSHARP) to study the gas's velocity in more detail. "With the high fidelity data from this program, we were able to measure the gas's velocity in three directions instead of just one," said Teague. "For the first time, we measured the motion of the gas rotating around the star, towards or away from the star, and up- or downwards in the disk."
Unique gas flows
Teague and his colleagues saw the gas moving from the upper layers towards the middle of the disk at three different locations. "What most likely happens is that a planet in orbit around the star pushes the gas and dust aside, opening a gap," Teague explained. "The gas above the gap then collapses into it like a waterfall, causing a rotational flow of gas in the disk."
This is the best evidence to date that there are indeed planets being formed around HD 163296. But astronomers cannot say with one hundred percent certainty that the gas flows are caused by planets. For example, the star's magnetic field could also cause disturbances in the gas. "Right now, only a direct observation of the planets could rule out the other options. But the patterns of these gas flows are unique and it is very likely that they can only be caused by planets," said co-author Jaehan Bae of the Carnegie Institution for Science, who tested this theory with a computer simulation of the disk.
The location of the three predicted planets in this study correspond to the results from last year: they are likely located at 87, 140 and 237 AU. (An astronomical unit -- AU -- is the average distance from the Earth to the Sun.) The closest planet to HD 163296 is calculated to be half the mass of Jupiter, the middle planet is Jupiter-mass, and the farthest planet is twice as massive as Jupiter.
Planet atmospheres
Gas flows from the surface towards the midplane of the protoplanetary disk have been predicted by theoretical models to exist since the late '90s, but this is the first time that they have been observed. Not only can they be used to detect infant planets, they also shape our understanding of how gas giant planets obtain their atmospheres.
"Planets form in the middle layer of the disk, the so-called midplane. This is a cold place, shielded from radiation from the star," Teague explained. "We think that the gaps caused by planets bring in warmer gas from the more chemically active outer layers of the disk, and that this gas will form the atmosphere of the planet."
Teague and his team did not expect that they would be able to see this phenomenon. "The disk around HD 163296 is the brightest and biggest disk we can see with ALMA," said Teague. "But it was a big surprise to actually see these gas flows so clearly. The disks appears to be much more dynamic than we thought."
Read more at Science Daily
To get more certainty that these gaps are actually caused by planets, and to get a more complete view of planet formation, scientists study the gas in the disks in addition to dust. 99 percent of a protoplanetary disk's mass is gas, of which carbon monoxide (CO) gas is the brightest component, emitting at a very distinctive millimeter-wavelength light that ALMA can observe.
Last year, two teams of astronomers demonstrated a new planet-hunting technique using this gas. They measured the velocity of CO gas rotating in the disk around the young star HD 163296. Localized disturbances in the movements of the gas revealed three planet-like patterns in the disk.
In this new study, lead author Richard Teague from the University of Michigan and his team used new high-resolution ALMA data from the Disk Substructures at High Angular Resolution Project (DSHARP) to study the gas's velocity in more detail. "With the high fidelity data from this program, we were able to measure the gas's velocity in three directions instead of just one," said Teague. "For the first time, we measured the motion of the gas rotating around the star, towards or away from the star, and up- or downwards in the disk."
Unique gas flows
Teague and his colleagues saw the gas moving from the upper layers towards the middle of the disk at three different locations. "What most likely happens is that a planet in orbit around the star pushes the gas and dust aside, opening a gap," Teague explained. "The gas above the gap then collapses into it like a waterfall, causing a rotational flow of gas in the disk."
This is the best evidence to date that there are indeed planets being formed around HD 163296. But astronomers cannot say with one hundred percent certainty that the gas flows are caused by planets. For example, the star's magnetic field could also cause disturbances in the gas. "Right now, only a direct observation of the planets could rule out the other options. But the patterns of these gas flows are unique and it is very likely that they can only be caused by planets," said co-author Jaehan Bae of the Carnegie Institution for Science, who tested this theory with a computer simulation of the disk.
The location of the three predicted planets in this study correspond to the results from last year: they are likely located at 87, 140 and 237 AU. (An astronomical unit -- AU -- is the average distance from the Earth to the Sun.) The closest planet to HD 163296 is calculated to be half the mass of Jupiter, the middle planet is Jupiter-mass, and the farthest planet is twice as massive as Jupiter.
Planet atmospheres
Gas flows from the surface towards the midplane of the protoplanetary disk have been predicted by theoretical models to exist since the late '90s, but this is the first time that they have been observed. Not only can they be used to detect infant planets, they also shape our understanding of how gas giant planets obtain their atmospheres.
"Planets form in the middle layer of the disk, the so-called midplane. This is a cold place, shielded from radiation from the star," Teague explained. "We think that the gaps caused by planets bring in warmer gas from the more chemically active outer layers of the disk, and that this gas will form the atmosphere of the planet."
Teague and his team did not expect that they would be able to see this phenomenon. "The disk around HD 163296 is the brightest and biggest disk we can see with ALMA," said Teague. "But it was a big surprise to actually see these gas flows so clearly. The disks appears to be much more dynamic than we thought."
Read more at Science Daily
3-D printed coral could help endangered reefs
Natural disasters such as hurricanes often leave devastation in their wake. Residents living in affected areas are sometimes displaced or require temporary shelter while their homes -- or even neighborhoods -- are repaired or rebuilt.
But what if you are a fish and your home is a coral reef?
Researchers across the globe are searching for ways to help endangered reefs, and the animals that live there, withstand or recover from weather events, including bleaching and storms that can occur with increasingly warmer water temperatures.
One idea is to use 3D-printed coral models to replace or supplement coral reef systems that have been affected.
New research by the University of Delaware's Danielle Dixson and UD alumnus Emily Ruhl has shown that 3D-printed objects do not impact the behavior of coral-associated damselfish or the survival of a settling stony coral.
Further, the study demonstrated that fish showed no preference between materials used to 3D-print artificial corals, opening the door to using environmentally friendly materials, such as biodegradable cornstarch instead of plastic.
With mounting concerns about plastic pollution in the marine environment, it is timely evidence that can support environmentally conscious decisions about what is put in the ocean.
The researchers reported their results in PLOS One, a peer-reviewed open source journal.
Testing 3D-printed materials
Like others studying this problem, Dixson and Ruhl are looking for ways to keep the right animals on a reef after an emergency to fuel recovery. One important consideration is knowing that any 3D-printed material used won't harm coral or negatively affect fish behavior.
"If the fish on a reef won't use the 3D-printed coral models as a habitat in the wild, it could place them at greater risk for predation by other larger species," said Dixson, an associate professor in UD's College of Earth, Ocean and Environment's School of Marine Science and Policy. "If coral larvae won't settle on 3D-printed materials, they can't help to rebuild the reef."
In laboratory experiments, the researchers studied the behavior of damselfish and mustard hill coral larvae in the presence of a coral skeleton and four 3D-printed coral models made from different filaments. Blue-green damselfish (Chromis viridis) are a common coral-associated fish found in the Indian and Pacific Oceans, while mustard hill corals (Porites astreoides) are a stony coral found in the Caribbean Sea.
The 3D coral models were made by replicating a coral skeleton using 50 iPhone images of the coral taken from all angles and a 3D printer. The researchers 3D-printed four different artificial coral models from low-cost, widely available filaments, including polyester and two biodegradable materials, one made from cornstarch and another made from cornstarch combined with stainless steel powder.
The researchers placed the damselfish into a fish tank loaded with the coral skeleton and the four artificial habitat options, in what is known as a cafeteria-style choice experiment, and studied whether the fish preferred one habitat over another.
Behavior analysis showed the damselfish did not display a preference between the native coral skeleton and the 3D-printed coral materials. The fish's activity level, such as frequency of movement and distance the fish traveled in the tank, also remained unchanged regardless of what coral habitat they were provided.
Ruhl said she was surprised that the fish behaved the same near artificial coral even with a natural coral skeleton present.
"I thought the natural skeleton would elicit more docile (that is, accepting) behavior compared to 3D-printed objects," said Ruhl, who earned her master's degree in marine biosciences at UD in 2018. "But then we realized the small reef fish didn't care if the habitat was artificial or calcium carbonate, they just wanted protection."
The researchers' lab experiments also revealed that mustard hill coral larvae settled at much higher rates on 3D-printed surfaces compared to having no settlement surface at all, which could occur if a reef were flattened in a storm.
This is promising news since both reef-associated fish and coral are vulnerable animal species, making them a good proxy for understanding how other reef organisms will respond to 3D-printed materials in the open ocean.
As coral reefs degrade, they often lose structural complexity, which is a problem for reef-associated fish that rarely move more than 15 feet from home in their entire lives. Without proper habitat, coral reef associated juvenile fish don't grow up to be bigger fish, and without bigger fish that feed on competitive algae, the algae can overgrow live corals, causing destruction and placing the whole ecosystem at risk.
In ongoing work, the researchers are analyzing field data from Fiji where they deployed 3D-printed coral and tiles made from biodegradable cornstarch filaments after determining they were safe to use. They are analyzing what settled on the artificial tiles, with an eye toward methods that would support conservation efforts.
"Offering 3D-printed habitats is a way to provide reef organisms a structural starter kit that can become part of the landscape as fish and coral build their homes around the artificial coral," Dixson said. "And since the materials we selected are biodegradable, the artificial coral would naturally degrade over time as the live coral overgrows it."
In addition, 3D-printed coral models can be useful as a control for fish-related laboratory studies, enabling researchers to provide each fish an identical habitat, something that is currently not possible with the use of coral skeletons, Dixson said.
Read more at Science Daily
But what if you are a fish and your home is a coral reef?
Researchers across the globe are searching for ways to help endangered reefs, and the animals that live there, withstand or recover from weather events, including bleaching and storms that can occur with increasingly warmer water temperatures.
One idea is to use 3D-printed coral models to replace or supplement coral reef systems that have been affected.
New research by the University of Delaware's Danielle Dixson and UD alumnus Emily Ruhl has shown that 3D-printed objects do not impact the behavior of coral-associated damselfish or the survival of a settling stony coral.
Further, the study demonstrated that fish showed no preference between materials used to 3D-print artificial corals, opening the door to using environmentally friendly materials, such as biodegradable cornstarch instead of plastic.
With mounting concerns about plastic pollution in the marine environment, it is timely evidence that can support environmentally conscious decisions about what is put in the ocean.
The researchers reported their results in PLOS One, a peer-reviewed open source journal.
Testing 3D-printed materials
Like others studying this problem, Dixson and Ruhl are looking for ways to keep the right animals on a reef after an emergency to fuel recovery. One important consideration is knowing that any 3D-printed material used won't harm coral or negatively affect fish behavior.
"If the fish on a reef won't use the 3D-printed coral models as a habitat in the wild, it could place them at greater risk for predation by other larger species," said Dixson, an associate professor in UD's College of Earth, Ocean and Environment's School of Marine Science and Policy. "If coral larvae won't settle on 3D-printed materials, they can't help to rebuild the reef."
In laboratory experiments, the researchers studied the behavior of damselfish and mustard hill coral larvae in the presence of a coral skeleton and four 3D-printed coral models made from different filaments. Blue-green damselfish (Chromis viridis) are a common coral-associated fish found in the Indian and Pacific Oceans, while mustard hill corals (Porites astreoides) are a stony coral found in the Caribbean Sea.
The 3D coral models were made by replicating a coral skeleton using 50 iPhone images of the coral taken from all angles and a 3D printer. The researchers 3D-printed four different artificial coral models from low-cost, widely available filaments, including polyester and two biodegradable materials, one made from cornstarch and another made from cornstarch combined with stainless steel powder.
The researchers placed the damselfish into a fish tank loaded with the coral skeleton and the four artificial habitat options, in what is known as a cafeteria-style choice experiment, and studied whether the fish preferred one habitat over another.
Behavior analysis showed the damselfish did not display a preference between the native coral skeleton and the 3D-printed coral materials. The fish's activity level, such as frequency of movement and distance the fish traveled in the tank, also remained unchanged regardless of what coral habitat they were provided.
Ruhl said she was surprised that the fish behaved the same near artificial coral even with a natural coral skeleton present.
"I thought the natural skeleton would elicit more docile (that is, accepting) behavior compared to 3D-printed objects," said Ruhl, who earned her master's degree in marine biosciences at UD in 2018. "But then we realized the small reef fish didn't care if the habitat was artificial or calcium carbonate, they just wanted protection."
The researchers' lab experiments also revealed that mustard hill coral larvae settled at much higher rates on 3D-printed surfaces compared to having no settlement surface at all, which could occur if a reef were flattened in a storm.
This is promising news since both reef-associated fish and coral are vulnerable animal species, making them a good proxy for understanding how other reef organisms will respond to 3D-printed materials in the open ocean.
As coral reefs degrade, they often lose structural complexity, which is a problem for reef-associated fish that rarely move more than 15 feet from home in their entire lives. Without proper habitat, coral reef associated juvenile fish don't grow up to be bigger fish, and without bigger fish that feed on competitive algae, the algae can overgrow live corals, causing destruction and placing the whole ecosystem at risk.
In ongoing work, the researchers are analyzing field data from Fiji where they deployed 3D-printed coral and tiles made from biodegradable cornstarch filaments after determining they were safe to use. They are analyzing what settled on the artificial tiles, with an eye toward methods that would support conservation efforts.
"Offering 3D-printed habitats is a way to provide reef organisms a structural starter kit that can become part of the landscape as fish and coral build their homes around the artificial coral," Dixson said. "And since the materials we selected are biodegradable, the artificial coral would naturally degrade over time as the live coral overgrows it."
In addition, 3D-printed coral models can be useful as a control for fish-related laboratory studies, enabling researchers to provide each fish an identical habitat, something that is currently not possible with the use of coral skeletons, Dixson said.
Read more at Science Daily
Use of social media is taking place both online and offline
Social media has changed how people interact. However, social media use is neither static or specifically linked to certain platforms. Emerging technical capabilities, changes in lifestyle and time management as well as the increasing possibilities to engage in online and offline interaction simultaneously affect our use of social media. Those are some of the results from a new doctoral thesis on Instagram and social media from University of Gothenburg.
In her studies, PhD-student Beata Jungselius, has been focusing on Instagram use and conducted interviews with a group of users in 2012, while five years later returning to that same group of instagrammers to understand how their use of both Instagram as well as social media in general has changed over time.
"These kinds of studies, where researchers analyze users' own descriptions of their social media use over time are very rare. By returning to and conducting in-depth interviews with the same informants in different stages of their lives, with their varied lifestyles, occupations and family situations, I have managed to get access to their own reflections on what has affected their behaviors, attitudes and perceptions of social media over time," she says.
One of the most central factors that regulate how people use social media is related to changes in lifestyle and management of time.
"Some users described tensions within their use. For instance, someone described that on one hand she uses social media more now, but on the other hand, she is less active when doing so. Some explained that this, being less active now in terms of how they interact and post photos, has to do with having less time because of work, kids and family. Others described sort of a moral tension, as in wanting to keep up and engage with friends, but also striving to not be a person who is always on their phone," says Beata Jungselius.
Another prominent change in how people use social media has to do with privacy preferences.
"It is clear that people have moved towards keeping conversations more private. A lot of the interaction that was previously public is now taking place in closed forums, such as via direct messages, through chats or in closed groups," Jungselius says.
The changes in technical capabilities has also had an effect on use of social media platforms as the possibilities to communicate and interact had increased in 2017. In 2012, users had a more limited set of interactional resources to rely upon. In 2017, the users had access to a greater array of modes and could express themselves through text, photo and video, GIFs and stickers. In 2012 the platforms where more diversified where each and every one had their special feature, while today, all major social media platforms provide similar features.
Use of social media is always taking place in a larger context. Interaction on one social media platform is usually situated within a larger use, where the interaction evolves over different platforms. Also, according to Jungselius, users engage in a number of social media practices that are not always visible at first glance. Apart from producing, posting and interacting with content, users plan their own production and monitor other users and relate to social media even when not actively engaging with their phone. Usually, people engage in these activities simultaneously.
"Platforms become social as people interact on them. The more accustomed they become with these practices, the better they get at using them and are able to switch seamlessly between them. They monitor and reflect upon the feedback they get on their postings and take this feedback into account when planning their future activities. When using social media, users develop both technical and social skills. They become skilled social media users," says Beata Jungselius.
As we are constantly connected today, social media users develop an ability to be more or less present in an online context while interacting with someone between four eyes.
Read more at Science Daily
In her studies, PhD-student Beata Jungselius, has been focusing on Instagram use and conducted interviews with a group of users in 2012, while five years later returning to that same group of instagrammers to understand how their use of both Instagram as well as social media in general has changed over time.
"These kinds of studies, where researchers analyze users' own descriptions of their social media use over time are very rare. By returning to and conducting in-depth interviews with the same informants in different stages of their lives, with their varied lifestyles, occupations and family situations, I have managed to get access to their own reflections on what has affected their behaviors, attitudes and perceptions of social media over time," she says.
One of the most central factors that regulate how people use social media is related to changes in lifestyle and management of time.
"Some users described tensions within their use. For instance, someone described that on one hand she uses social media more now, but on the other hand, she is less active when doing so. Some explained that this, being less active now in terms of how they interact and post photos, has to do with having less time because of work, kids and family. Others described sort of a moral tension, as in wanting to keep up and engage with friends, but also striving to not be a person who is always on their phone," says Beata Jungselius.
Another prominent change in how people use social media has to do with privacy preferences.
"It is clear that people have moved towards keeping conversations more private. A lot of the interaction that was previously public is now taking place in closed forums, such as via direct messages, through chats or in closed groups," Jungselius says.
The changes in technical capabilities has also had an effect on use of social media platforms as the possibilities to communicate and interact had increased in 2017. In 2012, users had a more limited set of interactional resources to rely upon. In 2017, the users had access to a greater array of modes and could express themselves through text, photo and video, GIFs and stickers. In 2012 the platforms where more diversified where each and every one had their special feature, while today, all major social media platforms provide similar features.
Use of social media is always taking place in a larger context. Interaction on one social media platform is usually situated within a larger use, where the interaction evolves over different platforms. Also, according to Jungselius, users engage in a number of social media practices that are not always visible at first glance. Apart from producing, posting and interacting with content, users plan their own production and monitor other users and relate to social media even when not actively engaging with their phone. Usually, people engage in these activities simultaneously.
"Platforms become social as people interact on them. The more accustomed they become with these practices, the better they get at using them and are able to switch seamlessly between them. They monitor and reflect upon the feedback they get on their postings and take this feedback into account when planning their future activities. When using social media, users develop both technical and social skills. They become skilled social media users," says Beata Jungselius.
As we are constantly connected today, social media users develop an ability to be more or less present in an online context while interacting with someone between four eyes.
Read more at Science Daily
In a first, scientists pinpoint neural activity's role in human longevity
The brain's neural activity -- long implicated in disorders ranging from dementia to epilepsy -- also plays a role in human aging and life span, according to research led by scientists in the Blavatnik Institute at Harvard Medical School.
The study, published Oct. 16 in Nature, is based on findings from human brains, mice and worms and suggests that excessive activity in the brain is linked to shorter life spans, while suppressing such overactivity extends life.
The findings offer the first evidence that the activity of the nervous system affects human longevity. Although previous studies had suggested that parts of the nervous system influence aging in animals, the role of neural activity in aging, especially in humans, remained murky.
"An intriguing aspect of our findings is that something as transient as the activity state of neural circuits could have such far-ranging consequences for physiology and life span," said study senior author Bruce Yankner, professor of genetics at HMS and co-director of the Paul F. Glenn Center for the Biology of Aging.
Neural excitation appears to act along a chain of molecular events famously known to influence longevity: the insulin and insulin-like growth factor (IGF) signaling pathway.
The key in this signaling cascade appears to be a protein called REST, previously shown by the Yankner Lab to protect aging brains from dementia and other stresses.
Neural activity refers to the constant flicker of electrical currents and transmissions in the brain. Excessive activity, or excitation, could manifest in numerous ways, from a muscle twitch to a change in mood or thought, the authors said.
It's not yet clear from the study whether or how a person's thoughts, personality or behavior affect their longevity.
"An exciting future area of research will be to determine how these findings relate to such higher-order human brain functions," said Yankner.
The study could inform the design of new therapies for conditions that involve neural overactivity, such as Alzheimer's disease and bipolar disorder, the researchers said.
The findings raise the possibility that certain medicines, such as drugs that target REST, or certain behaviors, such as meditation, could extend life span by modulating neural activity.
Human variation in neural activity might have both genetic and environmental causes, which would open future avenues for therapeutic intervention, Yankner said.
All roads lead to REST
Yankner and colleagues began their investigation by analyzing gene expression patterns -- the extent to which various genes are turned on and off -- in donated brain tissue from hundreds of people who died at ages ranging from 60 to over 100.
The information had been collected through three separate research studies of older adults. Those analyzed in the current study were cognitively intact, meaning they had no dementia.
Immediately, a striking difference appeared between the older and younger study participants, said Yankner: The longest-lived people -- those over 85 -- had lower expression of genes related to neural excitation than those who died between the ages of 60 and 80.
Next came the question that all scientists confront: correlation or causation? Was this disparity in neural excitation merely occurring alongside more important factors determining life span, or were excitation levels directly affecting longevity? If so, how?
The team conducted a barrage of experiments, including genetic, cell and molecular biology tests in the model organism Caenorhabditis elegans; analyses of genetically altered mice; and additional brain tissue analyses of people who lived for more than a century.
These experiments revealed that altering neural excitation does indeed affect life span -- and illuminated what might be happening on a molecular level.
All signs pointed to the protein REST.
REST, which is known to regulate genes, also suppresses neural excitation, the researchers found. Blocking REST or its equivalent in the animal models led to higher neural activity and earlier deaths, while boosting REST did the opposite. And human centenarians had significantly more REST in the nuclei of their brain cells than people who died in their 70s or 80s.
"It was extremely exciting to see how all these different lines of evidence converged," said study co-author Monica Colaiácovo, professor of genetics at HMS, whose lab collaborated on the C. elegans work.
The researchers found that from worms to mammals, REST suppresses the expression of genes that are centrally involved in neural excitation, such as ion channels, neurotransmitter receptors and structural components of synapses.
Lower excitation in turn activates a family of proteins known as forkhead transcription factors. These proteins have been shown to mediate a "longevity pathway" via insulin/IGF signaling in many animals. It's the same pathway that scientists believe can be activated by caloric restriction.
In addition to its emerging role in staving off neurodegeneration, discovery of REST's role in longevity provides additional motivation to develop drugs that target the protein.
Although it will take time and many tests to determine whether such treatments reduce neural excitation, promote healthy aging or extend life span, the concept has captivated some researchers.
"The possibility that being able to activate REST would reduce excitatory neural activity and slow aging in humans is extremely exciting," said Colaiácovo.
The authors emphasize that the work would not have been possible without large research cohorts of aging people.
"We now have enough people enrolled in these studies to partition the aging population into genetic subgroups," said Yankner. "This information is invaluable and shows why it's so important to support the future of human genetics."
Read more at Science Daily
The study, published Oct. 16 in Nature, is based on findings from human brains, mice and worms and suggests that excessive activity in the brain is linked to shorter life spans, while suppressing such overactivity extends life.
The findings offer the first evidence that the activity of the nervous system affects human longevity. Although previous studies had suggested that parts of the nervous system influence aging in animals, the role of neural activity in aging, especially in humans, remained murky.
"An intriguing aspect of our findings is that something as transient as the activity state of neural circuits could have such far-ranging consequences for physiology and life span," said study senior author Bruce Yankner, professor of genetics at HMS and co-director of the Paul F. Glenn Center for the Biology of Aging.
Neural excitation appears to act along a chain of molecular events famously known to influence longevity: the insulin and insulin-like growth factor (IGF) signaling pathway.
The key in this signaling cascade appears to be a protein called REST, previously shown by the Yankner Lab to protect aging brains from dementia and other stresses.
Neural activity refers to the constant flicker of electrical currents and transmissions in the brain. Excessive activity, or excitation, could manifest in numerous ways, from a muscle twitch to a change in mood or thought, the authors said.
It's not yet clear from the study whether or how a person's thoughts, personality or behavior affect their longevity.
"An exciting future area of research will be to determine how these findings relate to such higher-order human brain functions," said Yankner.
The study could inform the design of new therapies for conditions that involve neural overactivity, such as Alzheimer's disease and bipolar disorder, the researchers said.
The findings raise the possibility that certain medicines, such as drugs that target REST, or certain behaviors, such as meditation, could extend life span by modulating neural activity.
Human variation in neural activity might have both genetic and environmental causes, which would open future avenues for therapeutic intervention, Yankner said.
All roads lead to REST
Yankner and colleagues began their investigation by analyzing gene expression patterns -- the extent to which various genes are turned on and off -- in donated brain tissue from hundreds of people who died at ages ranging from 60 to over 100.
The information had been collected through three separate research studies of older adults. Those analyzed in the current study were cognitively intact, meaning they had no dementia.
Immediately, a striking difference appeared between the older and younger study participants, said Yankner: The longest-lived people -- those over 85 -- had lower expression of genes related to neural excitation than those who died between the ages of 60 and 80.
Next came the question that all scientists confront: correlation or causation? Was this disparity in neural excitation merely occurring alongside more important factors determining life span, or were excitation levels directly affecting longevity? If so, how?
The team conducted a barrage of experiments, including genetic, cell and molecular biology tests in the model organism Caenorhabditis elegans; analyses of genetically altered mice; and additional brain tissue analyses of people who lived for more than a century.
These experiments revealed that altering neural excitation does indeed affect life span -- and illuminated what might be happening on a molecular level.
All signs pointed to the protein REST.
REST, which is known to regulate genes, also suppresses neural excitation, the researchers found. Blocking REST or its equivalent in the animal models led to higher neural activity and earlier deaths, while boosting REST did the opposite. And human centenarians had significantly more REST in the nuclei of their brain cells than people who died in their 70s or 80s.
"It was extremely exciting to see how all these different lines of evidence converged," said study co-author Monica Colaiácovo, professor of genetics at HMS, whose lab collaborated on the C. elegans work.
The researchers found that from worms to mammals, REST suppresses the expression of genes that are centrally involved in neural excitation, such as ion channels, neurotransmitter receptors and structural components of synapses.
Lower excitation in turn activates a family of proteins known as forkhead transcription factors. These proteins have been shown to mediate a "longevity pathway" via insulin/IGF signaling in many animals. It's the same pathway that scientists believe can be activated by caloric restriction.
In addition to its emerging role in staving off neurodegeneration, discovery of REST's role in longevity provides additional motivation to develop drugs that target the protein.
Although it will take time and many tests to determine whether such treatments reduce neural excitation, promote healthy aging or extend life span, the concept has captivated some researchers.
"The possibility that being able to activate REST would reduce excitatory neural activity and slow aging in humans is extremely exciting," said Colaiácovo.
The authors emphasize that the work would not have been possible without large research cohorts of aging people.
"We now have enough people enrolled in these studies to partition the aging population into genetic subgroups," said Yankner. "This information is invaluable and shows why it's so important to support the future of human genetics."
Read more at Science Daily
Oct 15, 2019
Fire blankets can protect buildings from wildfires
Wrapping a building in a fire-protective blanket is a viable way of protecting it against wildfires, finds the first study to scientifically assesses this method of defense.
By rigorously testing different fabric materials in the laboratory and using them to shield structures that were exposed to fires of increasing magnitude, this research, published in Frontiers in Mechanical Engineering, confirms that existing blanket technology can protect structures from a short wildfire attack. For successful deployment against severe fires and in areas of high housing density, technological advancement of blanket materials and deployment methods, as well as multi-structure protection strategies, are needed.
"The whole-house fire blanket is a viable method of protection against fires at the wildland-urban interface," says lead study author Fumiaki Takahashi, a Professor at Case Western Reserve University, Cleveland, Ohio, USA, who teamed up with the NASA Glenn Research Center, U.S. Forest Service, New Jersey Forest Fire Service, and Cuyahoga Community College for this study.
He continues, "Current technology can protect an isolated structure against a relatively short wildfire attack and further technological developments are likely to enable this method to be applied to severe situations."
A burning need
Wildfires in urban and suburban settings can have a devastating effect on communities and pose one of the greatest fire challenges of our time.
People living and working in fire-risk areas contacted Professor Takahashi to find out if commercial products are available to help reduce the likelihood of structure ignition, which would reduce fire damage and improve public and firefighter safety. These pleas motivated the research and an initial investigation revealed that the concept of whole-structure fire blankets has been around for quite some time.
"I thought about a means to reduce wildland fire damage and found a U.S. patent 'conflagration-retardative curtain' i.e., a fire blanket, issued during World War Two. In addition, the U.S. Forest Service firefighters managed to save a historic forest cabin by wrapping it with their fire shelter materials," Takahashi reports.
An old flame-retardant
While there are anecdotal reports on the ability of fire blankets to protect buildings from fires, Takahashi's research highlighted a severe lack of scientific evidence to back up these claims. To rectify this, funded by a research grant from the U.S. Department of Homeland Security, the team conducted several experiments to test the ability of different blanket materials to shield structures against fires of increasing magnitude.
"The fire exposure tests determined how well the fire blankets protected various wooden structures, from a birdhouse in a burning room to a full-size shed in a real forest fire. We tested four types of fabric materials: aramid, fiberglass, amorphous silica, and pre-oxidized carbon, each with and without an aluminum surface. In addition, we conducted laboratory experiments under controlled heat exposure and measured the heat-insulation capabilities of these materials against direct flame contact or radiation heat."
A hot new industry
The laboratory and real-fire assessments demonstrate that fire blankets could protect structures from a short exposure to a wildfire, but also highlight the technical limitations of their existing form. Further technological advancements are needed in the areas of material composition, deployment methods and multi-structure protection strategies.
Takahashi explains, "The fiberglass or amorphous silica fabrics laminated with aluminum foil performed best, due to high reflection/emission of radiation and good thermal insulation by the fabric. New technology is needed to enhance the fire blankets' heat-blocking capability for an extended period to prevent structure-to-structure ignition. In addition, it will be more effective If dozens or hundreds of homes are protected by such advanced fire blankets at the same time, particularly in high housing-density Wildland-Urban Interface communities."
He concludes by suggesting communities potentially affected by wildfires work together to turn the concept of whole-building fire blankets into a reality.
Read more at Science Daily
By rigorously testing different fabric materials in the laboratory and using them to shield structures that were exposed to fires of increasing magnitude, this research, published in Frontiers in Mechanical Engineering, confirms that existing blanket technology can protect structures from a short wildfire attack. For successful deployment against severe fires and in areas of high housing density, technological advancement of blanket materials and deployment methods, as well as multi-structure protection strategies, are needed.
"The whole-house fire blanket is a viable method of protection against fires at the wildland-urban interface," says lead study author Fumiaki Takahashi, a Professor at Case Western Reserve University, Cleveland, Ohio, USA, who teamed up with the NASA Glenn Research Center, U.S. Forest Service, New Jersey Forest Fire Service, and Cuyahoga Community College for this study.
He continues, "Current technology can protect an isolated structure against a relatively short wildfire attack and further technological developments are likely to enable this method to be applied to severe situations."
A burning need
Wildfires in urban and suburban settings can have a devastating effect on communities and pose one of the greatest fire challenges of our time.
People living and working in fire-risk areas contacted Professor Takahashi to find out if commercial products are available to help reduce the likelihood of structure ignition, which would reduce fire damage and improve public and firefighter safety. These pleas motivated the research and an initial investigation revealed that the concept of whole-structure fire blankets has been around for quite some time.
"I thought about a means to reduce wildland fire damage and found a U.S. patent 'conflagration-retardative curtain' i.e., a fire blanket, issued during World War Two. In addition, the U.S. Forest Service firefighters managed to save a historic forest cabin by wrapping it with their fire shelter materials," Takahashi reports.
An old flame-retardant
While there are anecdotal reports on the ability of fire blankets to protect buildings from fires, Takahashi's research highlighted a severe lack of scientific evidence to back up these claims. To rectify this, funded by a research grant from the U.S. Department of Homeland Security, the team conducted several experiments to test the ability of different blanket materials to shield structures against fires of increasing magnitude.
"The fire exposure tests determined how well the fire blankets protected various wooden structures, from a birdhouse in a burning room to a full-size shed in a real forest fire. We tested four types of fabric materials: aramid, fiberglass, amorphous silica, and pre-oxidized carbon, each with and without an aluminum surface. In addition, we conducted laboratory experiments under controlled heat exposure and measured the heat-insulation capabilities of these materials against direct flame contact or radiation heat."
A hot new industry
The laboratory and real-fire assessments demonstrate that fire blankets could protect structures from a short exposure to a wildfire, but also highlight the technical limitations of their existing form. Further technological advancements are needed in the areas of material composition, deployment methods and multi-structure protection strategies.
Takahashi explains, "The fiberglass or amorphous silica fabrics laminated with aluminum foil performed best, due to high reflection/emission of radiation and good thermal insulation by the fabric. New technology is needed to enhance the fire blankets' heat-blocking capability for an extended period to prevent structure-to-structure ignition. In addition, it will be more effective If dozens or hundreds of homes are protected by such advanced fire blankets at the same time, particularly in high housing-density Wildland-Urban Interface communities."
He concludes by suggesting communities potentially affected by wildfires work together to turn the concept of whole-building fire blankets into a reality.
Read more at Science Daily
Survival strategy found in living corals which was only seen in fossil records
Some corals can recover after massive mortality episodes caused by the water temperature rise. This survival mechanism in the marine environment -known as rejuvenation- had only been described in some fossil corals so far. A new study published in the journal Science Advances reveals the first scientific evidence of the rejuvenation phenomenon in vivo in Cladocora caespitosa coral colonies, in the marine reserve in Columbrets, in the coast of Castellón (Spain).
The authors of the study are the experts Diego Kersting and Cristina Linares, from the Department of Evolutionary Biology, Ecology and Environmental Sciences from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona.
Heatwaves, more and more common in the Mediterranean
The Mediterranean Sea is one of the most affected areas by the climate change and the increase of heatwaves. "We are used to hear and read on the general impacts related to the climate change, but we rarely get news on the life recovery after impacts related to global warming," says Diego Kersting, first author of the article and researcher at the Free University of Berlin (Germany).
Since 2002, Kersting and Linares have been monitoring 250 coral colonies of Cladocora caespitosa in the marine reserve in Columbrets, an area for studies on the effects of climate change on the marine environment. This coral -the only one able to create reefs in the Mediterranean Sea- is listed as an endangered species, mainly because of the mortalities associated with global warming.
Experts had described that the unusual rise of water temperature in summer was killing many of these Mediterranean coral colonies. For instance, during the summer of 2003, one of the hottest ones, "the 25% of the surface occupied by these corals in Columbrets disappeared due a loss of the colonies," says the authors of the study.
Some coral polyps survive under extreme conditions
In a Mediterranean Sea with higher and higher temperatures and frequent heatwaves, the survival alarms for these species had already rang. However, the long-run monitoring of the coral in Columbrets revealed a surprising result: some coral colonies that were considered lost years ago show some living parts.
According to the experts, this kind of recuperation was possible thanks to a procedure named rejuvenation. In particular, under stress conditions -for instance, excessive water warming-, some polyps in the coral colonies which are dying are able to become smaller until they can abandon their calcareous skeleton.
In this reduced state, these polyps can survive under extreme conditions which cause the death of the other polyps in the colony. When conditions improve, polyps recover its common size and form a new calcareous skeleton. Afterwards, they reproduce by budding until the dead colony recovers.
A hidden survival strategy
According to the authors, this survival strategy had been unnoticed until now due the external good image the colonies show once they have recovered, which masks the mortality that had taken place before. "The real story of these colonies can only be found if controlled every year, over the years, or if we study the skeleton, since the process leaves characteristic features!, warn Kersting and Linares.
So far, researchers had found signs of this rejuvenation only in Paleozoic corals, which lived hundreds of millions of years ago. Therefore, the results of this study will enable making comparisons between the in vivo observations and the description through the fossils, and therefore knowing the implication of these kinds of survival processes and adaptation in corals.
Read more at Science Daily
The authors of the study are the experts Diego Kersting and Cristina Linares, from the Department of Evolutionary Biology, Ecology and Environmental Sciences from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona.
Heatwaves, more and more common in the Mediterranean
The Mediterranean Sea is one of the most affected areas by the climate change and the increase of heatwaves. "We are used to hear and read on the general impacts related to the climate change, but we rarely get news on the life recovery after impacts related to global warming," says Diego Kersting, first author of the article and researcher at the Free University of Berlin (Germany).
Since 2002, Kersting and Linares have been monitoring 250 coral colonies of Cladocora caespitosa in the marine reserve in Columbrets, an area for studies on the effects of climate change on the marine environment. This coral -the only one able to create reefs in the Mediterranean Sea- is listed as an endangered species, mainly because of the mortalities associated with global warming.
Experts had described that the unusual rise of water temperature in summer was killing many of these Mediterranean coral colonies. For instance, during the summer of 2003, one of the hottest ones, "the 25% of the surface occupied by these corals in Columbrets disappeared due a loss of the colonies," says the authors of the study.
Some coral polyps survive under extreme conditions
In a Mediterranean Sea with higher and higher temperatures and frequent heatwaves, the survival alarms for these species had already rang. However, the long-run monitoring of the coral in Columbrets revealed a surprising result: some coral colonies that were considered lost years ago show some living parts.
According to the experts, this kind of recuperation was possible thanks to a procedure named rejuvenation. In particular, under stress conditions -for instance, excessive water warming-, some polyps in the coral colonies which are dying are able to become smaller until they can abandon their calcareous skeleton.
In this reduced state, these polyps can survive under extreme conditions which cause the death of the other polyps in the colony. When conditions improve, polyps recover its common size and form a new calcareous skeleton. Afterwards, they reproduce by budding until the dead colony recovers.
A hidden survival strategy
According to the authors, this survival strategy had been unnoticed until now due the external good image the colonies show once they have recovered, which masks the mortality that had taken place before. "The real story of these colonies can only be found if controlled every year, over the years, or if we study the skeleton, since the process leaves characteristic features!, warn Kersting and Linares.
So far, researchers had found signs of this rejuvenation only in Paleozoic corals, which lived hundreds of millions of years ago. Therefore, the results of this study will enable making comparisons between the in vivo observations and the description through the fossils, and therefore knowing the implication of these kinds of survival processes and adaptation in corals.
Read more at Science Daily
Soil on moon and Mars likely to support crops
Researchers at Wageningen University & Research in the Netherlands have produced crops in Mars and Moon soil simulant developed by NASA. The research supports the idea that it would not only be possible to grow food on Mars and the Moon to feed future settlers, but also to obtain viable seed from crops grown there.
Wieger Wamelink and his colleagues at Wageningen University & Research, cultivated ten different crops: garden cress, rocket, tomato, radish, rye, quinoa, spinach, chives, peas and leek. The researchers simulated the properties of Lunar and Martian regolith and "normal" soil (potting soil from Earth) as a control.
Nine of the ten crops sown grew well and edible parts were harvested from them. Spinach was the exception. Total biomass production per tray was the highest for the Earth control and Mars soil simulant that differed significantly from Moon soil simulant. The seeds produced by three species (radish, rye and garden cress) were tested successfully for germination.
The article, "Crop growth and viability of seeds on Mars and Moon soil simulants," by Wieger Wamelink and colleagues has been published in De Gruyter's open access journal, Open Agriculture.
"We were thrilled when we saw the first tomatoes ever grown on Mars soil simulant turning red. It meant that the next step towards a sustainable closed agricultural ecosystem had been taken," said Wieger Wamelink.
From Science Daily
Wieger Wamelink and his colleagues at Wageningen University & Research, cultivated ten different crops: garden cress, rocket, tomato, radish, rye, quinoa, spinach, chives, peas and leek. The researchers simulated the properties of Lunar and Martian regolith and "normal" soil (potting soil from Earth) as a control.
Nine of the ten crops sown grew well and edible parts were harvested from them. Spinach was the exception. Total biomass production per tray was the highest for the Earth control and Mars soil simulant that differed significantly from Moon soil simulant. The seeds produced by three species (radish, rye and garden cress) were tested successfully for germination.
The article, "Crop growth and viability of seeds on Mars and Moon soil simulants," by Wieger Wamelink and colleagues has been published in De Gruyter's open access journal, Open Agriculture.
"We were thrilled when we saw the first tomatoes ever grown on Mars soil simulant turning red. It meant that the next step towards a sustainable closed agricultural ecosystem had been taken," said Wieger Wamelink.
From Science Daily
Monkeys outperform humans when it comes to cognitive flexibility
When it comes to being willing to explore more efficient options to solving a problem, monkeys exhibit more cognitive flexibility than humans, according to a study by Georgia State University psychology researchers.
"We are a unique species and have various ways in which we are exceptionally different from every other creature on the planet," said Julia Watzek, a graduate student in psychology at Georgia State. "But we're also sometimes really dumb."
Watzek was the lead author of a paper published in Scientific Reports illustrating how capuchin and rhesus macaque monkeys were significantly less susceptible than humans to "cognitive set" bias when presented a chance to switch to a more efficient option. The research results supported earlier studies with fellow primates, baboons and chimpanzees, who also showed a greater willingness to use optional shortcuts to earn a treat compared to humans who persisted in using a familiar learned strategy despite its relative inefficiency.
"I think we're less and less surprised when primates outsmart humans sometimes," Watzek said.
The test involved establishing a specific strategy to lead to a solution. Through trial and error using a computer, monkeys and humans had to follow a pattern by pushing a striped square then a dotted square and then, when it appeared, a triangle to achieve the goal and receive a reward. For the humans, the reward was either a jingle or points to let them know they got it right. For the monkeys, it was a banana pellet. Wrong results got a brief timeout and no reward.
After the strategy was learned, subsequent trials presented the triangle option immediately without having to push the patterned squares in sequence. All of the monkeys quickly used the shortcut, while 61 percent of the humans did not. In fact, 70 percent of all the monkeys used the shortcut the very first time it was available compared to only one human. (The study involved 56 humans, 22 capuchin and 7 rhesus monkeys.)
"There's a heavy reliance on rote learning and doing it the way you were taught and to specifically not take the shortcut," Watzek said of the human subjects.
"More of the humans do take the shortcut after seeing a video of somebody taking the shortcut, but about 30 percent still don't," Watzek said." In another version we told them they shouldn't be afraid to try something new. More of them did use the shortcut then, but many of them still didn't."
The study illustrates how humans can suffer from learned biases that can lead us to make inefficient decisions and miss opportunities. Often, sticking with what's familiar and proven -- like a commuting route to work -- isn't a big deal with a low cost over an alternative. Other times, using inefficient, biased or outdated practices could have far-reaching consequences. An example would be the most recent global financial crisis when many experts ignored instability warnings and continued practicing risky trading and lending habits that led to a housing market crash.
"To set ourselves up for good decision-making, sometimes that means changing available options," Watzek said. "I'm not proposing to topple the entire Western education system, but it is interesting to think through ways in which we train our children to think a specific way and stay in the box and not outside of it. Just be mindful of it. There are good reasons for why we do what we do, but I think sometimes it can get us into a lot of trouble."
Study co-author Sarah Pope, a former graduate student in the Neuroscience Institute at Georgia State, took the experiment to Namibia and tested it on members of the semi-nomadic Himba tribe, which is not exposed to Western education and lives in a less predictable environment. While more were quicker to use the shortcut immediately, more than half still used the three-step approach as well. In tests of visitors at Zoo Atlanta, children 7-10 were four times more likely than adults to use the shortcut but still more than half continued to use the learned strategy.
Read more at Science Daily
"We are a unique species and have various ways in which we are exceptionally different from every other creature on the planet," said Julia Watzek, a graduate student in psychology at Georgia State. "But we're also sometimes really dumb."
Watzek was the lead author of a paper published in Scientific Reports illustrating how capuchin and rhesus macaque monkeys were significantly less susceptible than humans to "cognitive set" bias when presented a chance to switch to a more efficient option. The research results supported earlier studies with fellow primates, baboons and chimpanzees, who also showed a greater willingness to use optional shortcuts to earn a treat compared to humans who persisted in using a familiar learned strategy despite its relative inefficiency.
"I think we're less and less surprised when primates outsmart humans sometimes," Watzek said.
The test involved establishing a specific strategy to lead to a solution. Through trial and error using a computer, monkeys and humans had to follow a pattern by pushing a striped square then a dotted square and then, when it appeared, a triangle to achieve the goal and receive a reward. For the humans, the reward was either a jingle or points to let them know they got it right. For the monkeys, it was a banana pellet. Wrong results got a brief timeout and no reward.
After the strategy was learned, subsequent trials presented the triangle option immediately without having to push the patterned squares in sequence. All of the monkeys quickly used the shortcut, while 61 percent of the humans did not. In fact, 70 percent of all the monkeys used the shortcut the very first time it was available compared to only one human. (The study involved 56 humans, 22 capuchin and 7 rhesus monkeys.)
"There's a heavy reliance on rote learning and doing it the way you were taught and to specifically not take the shortcut," Watzek said of the human subjects.
"More of the humans do take the shortcut after seeing a video of somebody taking the shortcut, but about 30 percent still don't," Watzek said." In another version we told them they shouldn't be afraid to try something new. More of them did use the shortcut then, but many of them still didn't."
The study illustrates how humans can suffer from learned biases that can lead us to make inefficient decisions and miss opportunities. Often, sticking with what's familiar and proven -- like a commuting route to work -- isn't a big deal with a low cost over an alternative. Other times, using inefficient, biased or outdated practices could have far-reaching consequences. An example would be the most recent global financial crisis when many experts ignored instability warnings and continued practicing risky trading and lending habits that led to a housing market crash.
"To set ourselves up for good decision-making, sometimes that means changing available options," Watzek said. "I'm not proposing to topple the entire Western education system, but it is interesting to think through ways in which we train our children to think a specific way and stay in the box and not outside of it. Just be mindful of it. There are good reasons for why we do what we do, but I think sometimes it can get us into a lot of trouble."
Study co-author Sarah Pope, a former graduate student in the Neuroscience Institute at Georgia State, took the experiment to Namibia and tested it on members of the semi-nomadic Himba tribe, which is not exposed to Western education and lives in a less predictable environment. While more were quicker to use the shortcut immediately, more than half still used the three-step approach as well. In tests of visitors at Zoo Atlanta, children 7-10 were four times more likely than adults to use the shortcut but still more than half continued to use the learned strategy.
Read more at Science Daily
How mucus tames microbes
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| Illustration of bacterium Pseudomonas aeruginosa. |
A new study from MIT reveals that glycans -- branched sugar molecules found in mucus -- are responsible for most of this microbe-taming. There are hundreds of different glycans in mucus, and the MIT team discovered that these molecules can prevent bacteria from communicating with each other and forming infectious biofilms, effectively rendering them harmless.
"What we have in mucus is a therapeutic gold mine," says Katharina Ribbeck, the Mark Hyman, Jr. Career Development Professor of Biological Engineering at MIT. "These glycans have biological functions that are very broad and sophisticated. They have the ability to regulate how microbes behave and really tune their identity."
In this study, which appears today in Nature Microbiology, the researchers focused on glycans' interactions with Pseudomonas aeruginosa, an opportunistic pathogen that can cause infections in cystic fibrosis patients and people with compromised immune systems. Work now underway in Ribbeck's lab has shown that glycans can regulate the behavior of other microbes as well.
The lead author of the Nature Microbiology paper is MIT graduate student Kelsey Wheeler.
Powerful defenders
The average person produces several liters of mucus every day, and until recently this mucus was thought to function primarily as a lubricant and a physical barrier. However, Ribbeck and others have shown that mucus can actually interfere with bacterial behavior, preventing microbes from attaching to surfaces and communicating with one another.
In the new study, Ribbeck wanted to test whether glycans were involved in mucus' ability to control the behavior of microbes. These sugar molecules, a type of oligosaccharide, attach to proteins called mucins, the gel-forming building blocks of mucus, to form a bottlebrush-like structure. Mucus-associated glycans have been little studied, but Ribbeck thought they might play a major role in the microbe-disarming activity she had previously seen from mucus.
To explore that possibility, she isolated glycans and exposed them to Pseudomonas aeruginosa. Upon exposure to mucin glycans, the bacteria underwent broad shifts in behavior that rendered them less harmful to the host. For example, they no longer produced toxins, attached to or killed host cells, or expressed genes essential for bacterial communication.
This microbe-disarming activity had powerful consequences on the ability of this bacterium to establish infections. Ribbeck has shown that treatment of Pseudomonas-infected burn wounds with mucins and mucin glycans reduces bacterial proliferation, indicating the therapeutic potential of these virulence-neutralizing agents.
"We've seen that intact mucins have regulatory effects and can cause behavioral switches in a whole range of pathogens, but now we can pinpoint the molecular mechanism and the entities that are responsible for this, which are the glycans," Ribbeck says.
In these experiments, the researchers used collections of hundreds of glycans, but they now plan to study the effects of individual glycans, which may interact specifically with different pathways or different microbes.
Bacterial interactions
Pseudomonas aeruginosa is just one of many opportunistic pathogens that healthy mucus keeps in check. Ribbeck is now studying the role of glycans in regulating other pathogens, including Streptococcus and the fungus Candida albicans, and she is also working on identifying receptors on microbe cell surfaces that interact with glycans.
Her work on Streptococcus has shown that glycans can block horizontal gene transfer, a process that microbes often use to spread genes for drug resistance.
Ribbeck and other researchers are now interested in using what they have learned about mucins and glycans to develop artificial mucus, which could offer a new way to treat diseases stemming from lost or defective mucus.
Harnessing the powers of mucus could also lead to new ways to treat antibiotic-resistant infections, because it offers a complementary strategy to traditional antibiotics, Ribbeck says.
"What we find here is that nature has evolved the ability to disarm difficult microbes, instead of killing them. This would not only help limit selective pressure for developing resistance, because they are not under pressure to find ways to survive, but it should also help create and maintain a diverse microbiome," she says.
Ribbeck suspects that glycans in mucus also play a key role in determining the composition of the microbiome -- the trillions of bacterial cells that live inside the human body. Many of these microbes are beneficial to their human hosts, and glycans may be providing them with nutrients they need, or otherwise helping them to flourish, she says. In this way, mucus-associated glycans are similar to the many oligosaccharides found in human milk, which also contains a wide array of sugars that can regulate microbe behavior.
"This is a theme that is likely at play in many systems where the goal is to shape and manipulate communities inside the body, not just in humans but throughout the animal kingdom," Ribbeck says.
Read more at Science Daily
Oct 14, 2019
Evolutionary history of oaks
How oaks are related has long posed a challenge to scientists. Dr. Andrew Hipp, senior scientist at The Morton Arboretum, led an international team of 24 scientists to unravel the history of global oak diversity for the first time using DNA sequencing of 260 oak species, combined with genomic mapping and fossil data.
Fundamental questions about relationships between organisms and the genes that drive ecological diversification underlie the secrets of biodiversity. Understanding the past of this ecologically, economically and culturally important group provides a baseline of knowledge that will allow scientists to address additional questions about oaks and other trees, as well as help with conservation efforts.
"This paper demonstrates that oaks have repeatedly and globally diversified in response to ecological opportunity" says Hipp. "The changes in the global landscape have given us the gift of the oak diversity we observe today."
Patchwork of Histories
The new paper, to be published in New Phytologist, is available free through an Early View online for one month beginning October 14. The study provides the most detailed account to date of the evolutionary history of the world's oaks. Investigating which parts of the oak genome distinguish species from one another, researchers at The Morton Arboretum, in collaboration with 17 institutions around the world, discovered that each gene or stretch of DNA in the genome has the potential to record multiple histories; each section bears the history of speciation of one oak lineage, but it may record the history of hybridization for a different lineage. In other words, there is no one region of the genome that defines oaks: it is the patchwork of histories embedded in the genome that characterize the history of oak evolution.
In addition, this research shows that different oak lineages have repeatedly diversified in the same area. Red oaks, white oaks, ring-cupped oaks, turkey and cork oaks, and three of the other oak sections arose rapidly and segregated to either the Americas or Eurasia. All of these lineages can be found in part of their range with at least one other lineage. As oaks migrated, species interbred, hybridized and diversified opportunistically in response to changes in the landscape. The highest rates of species diversification have been in response to migrations into new territory. Over and over, oaks have taken advantage of ecological opportunity to produce the diversity we see today, providing humans with ships, homes, wine barrels, furniture and acorns to eat, and providing food and homes for countless insects, mammals, birds and fungi.
"For the first time, this paper demonstrates that the history of different [oak] lineages is driven by different sets of genes," said co-author Dr. Antoine Kremer from the French National Institute for Agricultural Research. "The story of oak evolution is especially fascinating due to the ecological and morphological convergence in different oak lineages that cohabit on the same continent."
Read more at Science Daily
Fundamental questions about relationships between organisms and the genes that drive ecological diversification underlie the secrets of biodiversity. Understanding the past of this ecologically, economically and culturally important group provides a baseline of knowledge that will allow scientists to address additional questions about oaks and other trees, as well as help with conservation efforts.
"This paper demonstrates that oaks have repeatedly and globally diversified in response to ecological opportunity" says Hipp. "The changes in the global landscape have given us the gift of the oak diversity we observe today."
Patchwork of Histories
The new paper, to be published in New Phytologist, is available free through an Early View online for one month beginning October 14. The study provides the most detailed account to date of the evolutionary history of the world's oaks. Investigating which parts of the oak genome distinguish species from one another, researchers at The Morton Arboretum, in collaboration with 17 institutions around the world, discovered that each gene or stretch of DNA in the genome has the potential to record multiple histories; each section bears the history of speciation of one oak lineage, but it may record the history of hybridization for a different lineage. In other words, there is no one region of the genome that defines oaks: it is the patchwork of histories embedded in the genome that characterize the history of oak evolution.
In addition, this research shows that different oak lineages have repeatedly diversified in the same area. Red oaks, white oaks, ring-cupped oaks, turkey and cork oaks, and three of the other oak sections arose rapidly and segregated to either the Americas or Eurasia. All of these lineages can be found in part of their range with at least one other lineage. As oaks migrated, species interbred, hybridized and diversified opportunistically in response to changes in the landscape. The highest rates of species diversification have been in response to migrations into new territory. Over and over, oaks have taken advantage of ecological opportunity to produce the diversity we see today, providing humans with ships, homes, wine barrels, furniture and acorns to eat, and providing food and homes for countless insects, mammals, birds and fungi.
"For the first time, this paper demonstrates that the history of different [oak] lineages is driven by different sets of genes," said co-author Dr. Antoine Kremer from the French National Institute for Agricultural Research. "The story of oak evolution is especially fascinating due to the ecological and morphological convergence in different oak lineages that cohabit on the same continent."
Read more at Science Daily
Astronomers use giant galaxy cluster as X-ray magnifying lens
Astronomers at MIT and elsewhere have used a massive cluster of galaxies as an X-ray magnifying glass to peer back in time, to nearly 9.4 billion years ago. In the process, they spotted a tiny dwarf galaxy in its very first, high-energy stages of star formation.
While galaxy clusters have been used to magnify objects at optical wavelengths, this is the first time scientists have leveraged these massive gravitational giants to zoom in on extreme, distant, X-ray-emitting phenomena.
What they detected appears to be a blue speck of an infant galaxy, about 1/10,000 the size of our Milky Way, in the midst of churning out its first stars -- supermassive, cosmically short-lived objects that emit high-energy X-rays, which the researchers detected in the form of a bright blue arc.
"It's this little blue smudge, meaning it's a very small galaxy that contains a lot of super-hot, very massive young stars that formed recently," says Matthew Bayliss, a research scientist in MIT's Kavli Institute for Astrophysics and Space Research. "This galaxy is similar to the very first galaxies that formed in the universe ... the kind of which no one has ever seen in X-ray in the distant universe before."
Bayliss says the detection of this single, distant galaxy is proof that scientists can use galaxy clusters as natural X-ray magnifiers, to pick out extreme, highly energetic phenomena in the universe's early history.
"With this technique, we could, in the future, zoom in on a distant galaxy and age-date different parts of it -- to say, this part has stars that formed 200 million years ago, versus another part that formed 50 million years ago, and pick them apart in a way you cannot otherwise do," says Bayliss, who will be moving on to the University of Cincinnati as an assistant professor of physics.
He and his co-authors, including Michael McDonald, assistant professor of physics at MIT, have published their results in the journal Nature Astronomy.
A candle in the light
Galaxy clusters are the most massive objects in the universe, composed of thousands of galaxies, all bound together by gravity as one enormous, powerful force. Galaxy clusters are so massive, and their gravitational pull is so strong, that they can distort the fabric of space-time, bending the universe and any surrounding light, much like an elephant would stretch and warp a trapeze net.
Scientists have used galaxy clusters as cosmic magnifying glasses, with a technique known as gravitational lensing. The idea is that if scientists can approximate the mass of a galaxy cluster, they can estimate its gravitational effects on any surrounding light, as well as the angle at which a cluster may deflect that light.
For instance, imagine if an observer, facing a galaxy cluster, were trying to detect an object, such as a single galaxy, behind that cluster. The light emitted by that object would travel straight toward the cluster, then bend around the cluster. It would continue traveling toward the observer, though at slightly different angles, appearing to the observer as mirrored images of the same object, which in the end can be combined as a single, "magnified" image.
Scientists have used galaxy clusters to magnify objects at optical wavelengths, but never in the X-ray band of the electromagnetic spectrum, mainly because galaxy clusters themselves emit an enormous amount of X-rays. Scientists have thought that any X-rays coming from a background source would be impossible to discern from the cluster's own glare.
"If you're trying to see an X-ray source behind a cluster, it's like trying to see a candle next to a really bright light," Bayliss says. "So we knew this was a challenging measurement to make."
X-ray subtraction
The researchers wondered: Could they subtract that bright light and see the candle behind it? In other words, could they remove the X-ray emissions coming from the galaxy cluster, to view the much fainter X-rays coming from an object, behind and magnified by the cluster?
The team tested this idea with observations taken by NASA's Chandra X-ray Observatory, one of the world's most powerful X-ray space telescopes. They looked in particular at Chandra's measurements of the Phoenix cluster, a distant galaxy cluster located 5.7 billion light-years from Earth, which has been estimated to be about a quadrillion times as massive as the sun, with gravitational effects that should make it a powerful, natural magnifying lens.
"The idea is to take whatever your best X-ray telescope is -- in this case, Chandra -- and use a natural lens to magnify and effectively make Chandra bigger, so you can see more distant things," Bayliss says.
He and his colleagues analyzed observations of the Phoenix cluster, taken continuously by Chandra for over a month. They also looked at images of the cluster taken by two optical and infrared telescopes -- the Hubble Space Telescope and the Magellan telescope in Chile. With all these various views, the team developed a model to characterize the cluster's optical effects, which allowed the researchers to precisely measure the X-ray emissions from the cluster itself, and subtract it from the data.
They were left with two similar patterns of X-ray emissions around the cluster, which they determined were "lensed," or gravitationally bent, by the cluster. When they traced the emissions backward in time, they found that they all originated from a single, distant source: a tiny dwarf galaxy from 9.4 billion years ago, when the universe itself was roughly 4.4 billion years old -- about a third of its current age.
"Previously, Chandra had seen only a handful of things at this distance," Bayliss says. "In less than 10 percent of the time, we discovered this object, similarly far away. And gravitational lensing is what let us do it."
The combination of Chandra and the Phoenix cluster's natural lensing power enabled the team to see the tiny galaxy hiding behind the cluster, magnified about 60 times. At this resolution, they were able to zoom in to discern two distinct clumps within the galaxy, one producing many more X-rays than the other.
As X-rays are typically produced during extreme, short-lived phenomena, the researchers believe that the first X-ray-rich clump signals a part of the dwarf galaxy that has very recently formed supermassive stars, while the quieter region is an older region that contains more mature stars.
Read more at Science Daily
While galaxy clusters have been used to magnify objects at optical wavelengths, this is the first time scientists have leveraged these massive gravitational giants to zoom in on extreme, distant, X-ray-emitting phenomena.
What they detected appears to be a blue speck of an infant galaxy, about 1/10,000 the size of our Milky Way, in the midst of churning out its first stars -- supermassive, cosmically short-lived objects that emit high-energy X-rays, which the researchers detected in the form of a bright blue arc.
"It's this little blue smudge, meaning it's a very small galaxy that contains a lot of super-hot, very massive young stars that formed recently," says Matthew Bayliss, a research scientist in MIT's Kavli Institute for Astrophysics and Space Research. "This galaxy is similar to the very first galaxies that formed in the universe ... the kind of which no one has ever seen in X-ray in the distant universe before."
Bayliss says the detection of this single, distant galaxy is proof that scientists can use galaxy clusters as natural X-ray magnifiers, to pick out extreme, highly energetic phenomena in the universe's early history.
"With this technique, we could, in the future, zoom in on a distant galaxy and age-date different parts of it -- to say, this part has stars that formed 200 million years ago, versus another part that formed 50 million years ago, and pick them apart in a way you cannot otherwise do," says Bayliss, who will be moving on to the University of Cincinnati as an assistant professor of physics.
He and his co-authors, including Michael McDonald, assistant professor of physics at MIT, have published their results in the journal Nature Astronomy.
A candle in the light
Galaxy clusters are the most massive objects in the universe, composed of thousands of galaxies, all bound together by gravity as one enormous, powerful force. Galaxy clusters are so massive, and their gravitational pull is so strong, that they can distort the fabric of space-time, bending the universe and any surrounding light, much like an elephant would stretch and warp a trapeze net.
Scientists have used galaxy clusters as cosmic magnifying glasses, with a technique known as gravitational lensing. The idea is that if scientists can approximate the mass of a galaxy cluster, they can estimate its gravitational effects on any surrounding light, as well as the angle at which a cluster may deflect that light.
For instance, imagine if an observer, facing a galaxy cluster, were trying to detect an object, such as a single galaxy, behind that cluster. The light emitted by that object would travel straight toward the cluster, then bend around the cluster. It would continue traveling toward the observer, though at slightly different angles, appearing to the observer as mirrored images of the same object, which in the end can be combined as a single, "magnified" image.
Scientists have used galaxy clusters to magnify objects at optical wavelengths, but never in the X-ray band of the electromagnetic spectrum, mainly because galaxy clusters themselves emit an enormous amount of X-rays. Scientists have thought that any X-rays coming from a background source would be impossible to discern from the cluster's own glare.
"If you're trying to see an X-ray source behind a cluster, it's like trying to see a candle next to a really bright light," Bayliss says. "So we knew this was a challenging measurement to make."
X-ray subtraction
The researchers wondered: Could they subtract that bright light and see the candle behind it? In other words, could they remove the X-ray emissions coming from the galaxy cluster, to view the much fainter X-rays coming from an object, behind and magnified by the cluster?
The team tested this idea with observations taken by NASA's Chandra X-ray Observatory, one of the world's most powerful X-ray space telescopes. They looked in particular at Chandra's measurements of the Phoenix cluster, a distant galaxy cluster located 5.7 billion light-years from Earth, which has been estimated to be about a quadrillion times as massive as the sun, with gravitational effects that should make it a powerful, natural magnifying lens.
"The idea is to take whatever your best X-ray telescope is -- in this case, Chandra -- and use a natural lens to magnify and effectively make Chandra bigger, so you can see more distant things," Bayliss says.
He and his colleagues analyzed observations of the Phoenix cluster, taken continuously by Chandra for over a month. They also looked at images of the cluster taken by two optical and infrared telescopes -- the Hubble Space Telescope and the Magellan telescope in Chile. With all these various views, the team developed a model to characterize the cluster's optical effects, which allowed the researchers to precisely measure the X-ray emissions from the cluster itself, and subtract it from the data.
They were left with two similar patterns of X-ray emissions around the cluster, which they determined were "lensed," or gravitationally bent, by the cluster. When they traced the emissions backward in time, they found that they all originated from a single, distant source: a tiny dwarf galaxy from 9.4 billion years ago, when the universe itself was roughly 4.4 billion years old -- about a third of its current age.
"Previously, Chandra had seen only a handful of things at this distance," Bayliss says. "In less than 10 percent of the time, we discovered this object, similarly far away. And gravitational lensing is what let us do it."
The combination of Chandra and the Phoenix cluster's natural lensing power enabled the team to see the tiny galaxy hiding behind the cluster, magnified about 60 times. At this resolution, they were able to zoom in to discern two distinct clumps within the galaxy, one producing many more X-rays than the other.
As X-rays are typically produced during extreme, short-lived phenomena, the researchers believe that the first X-ray-rich clump signals a part of the dwarf galaxy that has very recently formed supermassive stars, while the quieter region is an older region that contains more mature stars.
Read more at Science Daily
Reading the past like an open book: Researchers use text to measure 200 years of happiness
Was there such a thing as 'the good old days' when people were happier? Are current Government policies more or less likely to increase their citizens' feelings of wellbeing?
Using innovative new methods researchers at the University of Warwick, University of Glasgow Adam Smith Business School and The Alan Turing Institute in London have built a new index that uses data from books and newspaper to track levels of national happiness from 1820. Their research could help governments to make better decisions about policy priorities.
Governments the world over are making increasing use of "national happiness" data derived from surveys to help them consider the impact of policy on national wellbeing. Unfortunately, data for most countries is only available from 2011 onwards, and for a select few from the mid 1970s. This makes it hard to establish long-run trends, or to say anything about the main historical causes of happiness.
In order to tackle this problem, a team of researchers including Professor Thomas Hills (Warwick and The Alan Turing Institute), Professor Eugenio Proto (Glasgow), Professor Daniel Sgroi (Warwick), and Dr Chanuki Seresinhe (The Alan Turing Institute) took a key insight from psychology -- that more often than not what people say or write reveals much about their underlying happiness level -- and developed a method to apply it to online texts from millions of books and newspapers published over the past 200 years.
The main source of language used for the analysis was the Google Books corpus, a collection of word frequency data for over 8 million books -- that's more than 6 per cent of all books ever published.
The method uses psychological valence norms -- values of happiness that can be derived from text -- for thousands of words in di?erent languages to compute the relative proportion of positive and negative language for four di?erent nations (the USA, UK, Germany and Italy). The research team also controlled for the evolution of language, to take into account the fact that some words change their meaning over time.
The new index was validated against existing survey-based measures and proven to be an accurate guide to the national mood. One theory as to why books and newspaper articles are such a good source of data is that editors prefer to publish pieces which match the mood of their readers.
Studying the index, the researchers found that:
Commenting on the findings, Professor Thomas Hills said: "What's remarkable is that national subjective well-being is incredibly resilient to wars. Even temporary economic booms and busts have little long-term effect. We can see the American Civil War in our data, the revolutions of 48' across Europe, the roaring 20's and the Great Depression. But people quickly returned to their previous levels of subjective well-being after these events were over. Our national happiness is like an adjustable spanner that we open and close to calibrate our experiences against our recent past, with little lasting memory for the triumphs and tragedies of our age."
Professor Eugenio Proto added: "Our index is an important first step in understanding people's satisfaction in the past. Looking at the Italian data, it is interesting to note a slow but constant decline in the years of fascism and a dramatic decline in the years after the last crisis."
Professor Daniel Sgroi said: 'Aspirations seem to matter a lot: after the end of rationing in the 1950s national happiness was very high as were expectations for the future, but unfortunately things did not pan out as people might have hoped and national happiness fell for many years until the low-point of the Winter of Discontent.'
Read more at Science Daily
Using innovative new methods researchers at the University of Warwick, University of Glasgow Adam Smith Business School and The Alan Turing Institute in London have built a new index that uses data from books and newspaper to track levels of national happiness from 1820. Their research could help governments to make better decisions about policy priorities.
Governments the world over are making increasing use of "national happiness" data derived from surveys to help them consider the impact of policy on national wellbeing. Unfortunately, data for most countries is only available from 2011 onwards, and for a select few from the mid 1970s. This makes it hard to establish long-run trends, or to say anything about the main historical causes of happiness.
In order to tackle this problem, a team of researchers including Professor Thomas Hills (Warwick and The Alan Turing Institute), Professor Eugenio Proto (Glasgow), Professor Daniel Sgroi (Warwick), and Dr Chanuki Seresinhe (The Alan Turing Institute) took a key insight from psychology -- that more often than not what people say or write reveals much about their underlying happiness level -- and developed a method to apply it to online texts from millions of books and newspapers published over the past 200 years.
The main source of language used for the analysis was the Google Books corpus, a collection of word frequency data for over 8 million books -- that's more than 6 per cent of all books ever published.
The method uses psychological valence norms -- values of happiness that can be derived from text -- for thousands of words in di?erent languages to compute the relative proportion of positive and negative language for four di?erent nations (the USA, UK, Germany and Italy). The research team also controlled for the evolution of language, to take into account the fact that some words change their meaning over time.
The new index was validated against existing survey-based measures and proven to be an accurate guide to the national mood. One theory as to why books and newspaper articles are such a good source of data is that editors prefer to publish pieces which match the mood of their readers.
Studying the index, the researchers found that:
- Increases in national income do generate increases in national happiness but it takes a huge rise to have a noticeable effect at the national level
- An increase in longevity of one year had the same effect on happiness as a 4.3 per cent increase in GDP
- One less year of war had the equivalent effect on happiness of a 30 per cent rise in GDP
- In post-war UK the worst period for national happiness occurred around the appropriately named "Winter of Discontent."
- In post-war USA the lowest point of the index coincides with the Vietnam War and the evacuation of Saigon.
Commenting on the findings, Professor Thomas Hills said: "What's remarkable is that national subjective well-being is incredibly resilient to wars. Even temporary economic booms and busts have little long-term effect. We can see the American Civil War in our data, the revolutions of 48' across Europe, the roaring 20's and the Great Depression. But people quickly returned to their previous levels of subjective well-being after these events were over. Our national happiness is like an adjustable spanner that we open and close to calibrate our experiences against our recent past, with little lasting memory for the triumphs and tragedies of our age."
Professor Eugenio Proto added: "Our index is an important first step in understanding people's satisfaction in the past. Looking at the Italian data, it is interesting to note a slow but constant decline in the years of fascism and a dramatic decline in the years after the last crisis."
Professor Daniel Sgroi said: 'Aspirations seem to matter a lot: after the end of rationing in the 1950s national happiness was very high as were expectations for the future, but unfortunately things did not pan out as people might have hoped and national happiness fell for many years until the low-point of the Winter of Discontent.'
Read more at Science Daily
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