Researchers at the Max Planck Institute and the Santa Fe Institute have developed a new model to explain the evolutionary origins of empathy and other related phenomena, such as emotional contagion and contagious yawning. The model suggests that the origin of a broad range of empathetic responses lies in cognitive simulation. It shifts the theoretical focus from a top-down approach that begins with cooperation to one that begins with a single cognitive mechanism.
According to Fabrizio Mafessoni, who is a post-doctoral researcher at the Max Planck Institute for Evolutionary Anthropology, standard theoretical models of the origins of empathy tend to focus on scenarios in which coordination or cooperation are favored.
Mafessoni, and his co-author Michael Lachmann, a theoretical biologist and Professor at the Santa Fe Institute, explored the possibility that the cognitive processes underlying a broad range of empathetic responses -- including emotional contagion, contagious yawning, and pathologies like echopraxia (compulsive repetition of others' movements) and echolalia (compulsive repetition of others' speech) -- could evolve in the absence of kin selection or any other mechanism directly favoring cooperation or coordination.
Mafessoni and Lachmann posited that animals, including humans, can engage in the act of simulating the minds of others. We cannot read other minds -- they are like black boxes to us. But, as Lachmann explains, all agents share almost identical "black boxes" with members of their species, and "they are constantly running simulations of what other minds might be doing." This ongoing as-actor simulation is not necessarily geared toward cooperation: it's just something humans and animals do spontaneously.
An example of this process is represented by mirror neurons: it has been known for some time that the same neurons engaged in planning a hand movement are also used when observing the hand movement of others. Mafessoni and Lachmann wondered what the consequences would be if they were to extend that process of understanding to any social interaction.
When they modeled outcomes rooted in cognitive simulation, they found that actors engaged in as-actor simulation produce a variety of systems typically explained in terms of cooperation or kin-selection. They also found that an observer can occasionally coordinate with an actor even when this outcome is not advantageous. Their model suggests that empathetic systems do not evolve solely because agents are disposed to cooperation and kin-selection. They also evolve because animals simulate others to envision their actions. According to Mafessoni, "the very origin of empathy may lie in the need to understand other individuals."
Read more at Science Daily
Apr 8, 2019
Hello, kitty: Cats recognize their own names, according to new Japanese research
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| Cats can learn to recognize their own names. |
The research was performed largely within the lab of Professor Toshikazu Hasegawa from the University of Tokyo with Atsuko Saito, Ph.D., first author of the research paper. Saito is now an associate professor at Sophia University in Tokyo.
Evolution of social cats
This is the first project to study cats' ability to understand human voices. Other research projects have discovered that apes, dolphins, parrots, and dogs can understand some words spoken by humans.
Saito speculates that mammals like dolphins and apes are naturally social animals and are therefore more inclined to interact with humans and respond to human cues.
"In comparison to those other species, cats are not so social. Cats interact with us when they want," said Saito.
Projects to understand simple social behaviors like name recognition in cats may give clues to how we humans became social. Both humans and cats have evolved through the process of self-domestication, where the population rewards certain traits that then become increasingly common in future generations.
"There may be a common feature in the evolutionary process of sociality between humans and cats. Since cats are still evolving to become more domesticated, there is a possibility that we can see the process of evolution of sociality by investigating the social cognition in cats," said Saito.
What's in a name?
To test if a cat recognized its name, researchers tested the name against other similar-sounding nouns. For example, a cat named Kari would also hear recordings of the words hifu (skin) and shuto (capital city).
Researchers played recordings of their own voices and the cat's owner's voice saying five words: the first four words were the similar-sounding nouns and the final, fifth word was the cat's name.
Researchers decided that cats responded to their name if they ignored recordings of other words, but moved their ears or heads when they heard their name. Cats rarely responded more enthusiastically, for example by moving their tails or bodies or by using their voice.
Cats who showed habituated weak responses to other similar-sounding nouns or the names of other cohabiting cats were significantly more likely to show strong responses to their own names.
Researchers state that a cat that did not respond to its name may still be able to recognize its name.
"Their lack of response may be caused by their low motivation level to interact with humans, or their feelings at the time of the experiment," said Saito.
Saito offers simple advice to any cat owners wishing to increase their communication with their cat: "Please interact with your cat when she shows that she wants to interact with you."
Single or many cats?
Researchers also tested if cats can distinguish between their own names and those of other cohabitating cats. Cats living in homes were more likely than cats living in a cat café to distinguish between their own names and the names of cohabitating cats.
Cat cafés are businesses where people pay for a drink and to interact with the many cats who live in the café.
Researchers suspect that owners use their cats' names specifically at home, whereas cat café visitors may use the cats' names interchangeably.
Researchers analyzed data from 77 different cats in the research project, which was broken into four separate experiments performed over three years.
Cats studied in the research were between six months to 17 years old, a mix of male and female, and were mostly mixed breeds. Most cats were spayed/neutered and all but one were indoor-only cats.
Professor Toshikazu Hasegawa is now retired from the University of Tokyo.
Research scientist Kazutaka Shinozuka, Ph.D., from the RIKEN Center for Brain Science also contributed to this research.
According to previous research, cats can distinguish between their owner's voice and a stranger's voice, can follow a person's pointing finger to find hidden food, and may change their behavior depending on their owner's facial expressions.
Read more at Science Daily
Melting glaciers causing sea levels to rise at ever greater rates
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| Regional share of glaciers in sea-level rise from 1961 to 2016. |
Glaciers have lost more than 9,000 billion tons (that is 9,625,000,000,000 tons) of ice between 1961 and 2016, which has resulted in global sea levels increasing by 27 millimeters in this period. The largest contributors were glaciers in Alaska, followed by the melting ice fields in Patagonia and glaciers in the Arctic regions. Glaciers in the European Alps, the Caucasus and New Zealand were also subject to significant ice loss; however, due to their relatively small glacierized areas they played only a minor role when it comes to the rising global sea levels.
Combination of field observations and satellite measurements
For the new study, the international research team combined glaciological field observations with geodetic satellite measurements. The latter digitally measure the surface of the Earth, providing data on ice thickness changes at different points in time. The researchers were thus able to reconstruct changes in the ice thickness of more than 19,000 glaciers worldwide. This was also possible thanks to the comprehensive database compiled by the World Glacier Monitoring Service from its worldwide network of observers, to which the researchers added their own satellite analyses. "By combining these two measurement methods and having the new comprehensive dataset, we can estimate how much ice has been lost each year in all mountain regions since the 1960s," explains Michael Zemp, who led the study. "The glaciological measurements made in the field provide the annual fluctuations, while the satellite data allows us to determine overall ice loss over several years or decades."
335 billion tons of ice lost each year
The global mass loss of glacier ice has increased significantly in the last 30 years and currently amounts to 335 billion tons of lost ice each year. This corresponds to an increase in sea levels of almost 1 millimeter per year. "Globally, we lose about three times the ice volume stored in the entirety of the European Alps -- every single year!" says glaciologist Zemp. The melted ice of glaciers therefore accounts for 25 to 30 percent of the current increase in global sea levels. This ice loss of all glaciers roughly corresponds to the mass loss of Greenland's Ice Sheet, and clearly exceeds that of the Antarctic.
From Science Daily
Apr 7, 2019
Medical guidelines may be biased, overly aggressive in US
Dr. Sunita Sah practiced general medicine for several years in the United Kingdom's National Health Service. When she came to the United States, she noticed something strange.
The U.K. guidelines for tests such as mammograms and colon cancer screenings drastically differed from those in the U.S. -- even though they were based on the same medical evidence.
"Having colonoscopy at the age of 50 -- that struck me as rather odd when I moved to the U.S., because you don't really hear about people having colonoscopies as a screening procedure in the U.K.," said Sah. "It's much less invasive to test for blood in the stool. It's also less costly and doesn't have the risks of undertaking a colonoscopy."
Now an assistant professor of management and organizations at Cornell, Sah and Ismail Jatoi of the University of Texas Health, San Antonio, say the treatment guidelines recommended by medical specialist organizations are more likely to call for greater use of health care services and exacerbate overdiagnosis, overtreatment and spiraling health care costs. Their commentary, "Clinical Practice Guidelines and the Overuse of Health Care Services: Need for Reform," appeared March 18 in the Canadian Medical Association Journal.
The implications are significant, she said, because guidelines are supposed to provide standard evidence-based treatment practices for all doctors.
"The recommendations put out by specialty organizations -- like the American College of Cardiology or the American College of Radiology -- show specialty bias in recommending more aggressive and/or more frequent screening procedures," said Sah, an expert on conflict of interest. "In the U.S. in particular, where the fee-for-service compensation model dominates medicine, which is different from countries like the U.K., you see even more recommendations for greater use of health care services."
Specialty bias refers to the tendency of physicians to recommend the treatments in which they are trained to deliver. For example, localized prostate cancer can be treated with either surgery or radiation.
"If you go to a surgeon, chances are that they are more likely to recommend that you have surgery; if you go to a radiation oncologist, they are more likely to recommend that you have radiation," she said. "They each often believe that the treatment that they're trained in is the better one."
In the case of screening for colorectal cancer, the American College of Gastroenterology's panel -- all of whom were gastroenterologists -- recommended colonoscopy as the best strategy.
But the United States Preventive Task Force, with no gastroenterologists or gastrointestinal surgeons, recommended testing the stool, sigmoidoscopy (an exam of only the lower part of the colon) or colonoscopy as a last resort. Stool testing was also recommended by the European Society of Medical Oncology panel, which consisted of six medical oncologists, no gastroenterologists and one gastrointestinal surgeon. The panel said there was limited evidence that screening colonoscopy is effective.
"Colonoscopies are more invasive than stool testing and come with potentially greater risks and costs for patients -- but increased clinical volume and profits for gastroenterologists," Sah said.
Specialty guidelines are also subject to fee-for-service bias, according to the commentary. Doctors who receive a payment for each treatment may tend to recommend that treatment more often, because they have a financial interest in it.
"The bias is not necessarily malicious or intentional," Sah said. "In a fee-for-service environment, they may be biased to do more rather than less, so it becomes a habit."
But more is not necessarily better, she said. "Sometimes the risks of those procedures are just not worth the benefits."
The authors call for a reduction in conflicts of interest in the fee-for-service model, and more professional diversity in the makeup of the guideline committees. "You need a variety of different voices on those committees," Sah said.
Read more at Science Daily
The U.K. guidelines for tests such as mammograms and colon cancer screenings drastically differed from those in the U.S. -- even though they were based on the same medical evidence.
"Having colonoscopy at the age of 50 -- that struck me as rather odd when I moved to the U.S., because you don't really hear about people having colonoscopies as a screening procedure in the U.K.," said Sah. "It's much less invasive to test for blood in the stool. It's also less costly and doesn't have the risks of undertaking a colonoscopy."
Now an assistant professor of management and organizations at Cornell, Sah and Ismail Jatoi of the University of Texas Health, San Antonio, say the treatment guidelines recommended by medical specialist organizations are more likely to call for greater use of health care services and exacerbate overdiagnosis, overtreatment and spiraling health care costs. Their commentary, "Clinical Practice Guidelines and the Overuse of Health Care Services: Need for Reform," appeared March 18 in the Canadian Medical Association Journal.
The implications are significant, she said, because guidelines are supposed to provide standard evidence-based treatment practices for all doctors.
"The recommendations put out by specialty organizations -- like the American College of Cardiology or the American College of Radiology -- show specialty bias in recommending more aggressive and/or more frequent screening procedures," said Sah, an expert on conflict of interest. "In the U.S. in particular, where the fee-for-service compensation model dominates medicine, which is different from countries like the U.K., you see even more recommendations for greater use of health care services."
Specialty bias refers to the tendency of physicians to recommend the treatments in which they are trained to deliver. For example, localized prostate cancer can be treated with either surgery or radiation.
"If you go to a surgeon, chances are that they are more likely to recommend that you have surgery; if you go to a radiation oncologist, they are more likely to recommend that you have radiation," she said. "They each often believe that the treatment that they're trained in is the better one."
In the case of screening for colorectal cancer, the American College of Gastroenterology's panel -- all of whom were gastroenterologists -- recommended colonoscopy as the best strategy.
But the United States Preventive Task Force, with no gastroenterologists or gastrointestinal surgeons, recommended testing the stool, sigmoidoscopy (an exam of only the lower part of the colon) or colonoscopy as a last resort. Stool testing was also recommended by the European Society of Medical Oncology panel, which consisted of six medical oncologists, no gastroenterologists and one gastrointestinal surgeon. The panel said there was limited evidence that screening colonoscopy is effective.
"Colonoscopies are more invasive than stool testing and come with potentially greater risks and costs for patients -- but increased clinical volume and profits for gastroenterologists," Sah said.
Specialty guidelines are also subject to fee-for-service bias, according to the commentary. Doctors who receive a payment for each treatment may tend to recommend that treatment more often, because they have a financial interest in it.
"The bias is not necessarily malicious or intentional," Sah said. "In a fee-for-service environment, they may be biased to do more rather than less, so it becomes a habit."
But more is not necessarily better, she said. "Sometimes the risks of those procedures are just not worth the benefits."
The authors call for a reduction in conflicts of interest in the fee-for-service model, and more professional diversity in the makeup of the guideline committees. "You need a variety of different voices on those committees," Sah said.
Read more at Science Daily
Digging ancient signals out of modern human genomes
With new genome analysis tools, scientists have made significant advances in our understanding of modern humans' origins and ancient migrations.
But trying to find ancient DNA, let alone prove that the ancient DNA is ancestral to a population living today is extremely challenging.
A new study in Molecular Biology and Evolution (MBE) adds to this understanding by reconstructing artificial genomes with the analyses of the genome of 565 contemporary South Asian individuals to extract ancient signals that recapitulate the long history of human migration and admixture in the region.
"All in all, our results provide a proof-of-principle for the feasibility of retrieving ancient genetic signals from contemporary human subjects, as if they were genomes from the past embedded in amber," said Luca Pagani, the research coordinator of the study.
The study was led by Burak Yelmen and Mayukh Mondal from the Institute of Genomics of the University of Tartu, Estonia and coordinated by Luca Pagani from the same institution and from the University of Padova, Italy.
"The genetic components we managed to extract from modern genomes are invaluable, given the shortage of ancient DNA available from South Asian human remains, and allow us to elucidate the genetic composition of the ancient populations that inhabited the area," said Burak Yelmen, co-first author of the study.
While studying the mixing events that brought ancient human populations to form contemporary South Asians, the researchers also noted that some portion of the genomes had not mixed as expected, as if the genetic variants that evolved in South Asia or the ones that arrived from West Eurasia were important for adapting to the local lifestyle through admixture.
"Among these variants, we found genes important for immunity and for dietary changes, as one may expect for human populations adapting to new sets of pathogens or food," said Mayukh Mondal, joint first author of this work.
The human evolution of skin pigmentation also revealed many genetic variants for the population studied.
"Intriguingly we also noted that some genetic variants implicated in the skin pigmentation of West Eurasians were under opposite selective forces, some becoming highly frequent and others being almost lost after the admixture events. Skin pigmentation is surely a fascinating and complex subject and we are still trying to understand what, if any, would be the adaptive implications of the signal we detected."
The study will add to the growing picture of the diversity of South Asians, and future studies of modern human population origins.
Read more at Science Daily
But trying to find ancient DNA, let alone prove that the ancient DNA is ancestral to a population living today is extremely challenging.
A new study in Molecular Biology and Evolution (MBE) adds to this understanding by reconstructing artificial genomes with the analyses of the genome of 565 contemporary South Asian individuals to extract ancient signals that recapitulate the long history of human migration and admixture in the region.
"All in all, our results provide a proof-of-principle for the feasibility of retrieving ancient genetic signals from contemporary human subjects, as if they were genomes from the past embedded in amber," said Luca Pagani, the research coordinator of the study.
The study was led by Burak Yelmen and Mayukh Mondal from the Institute of Genomics of the University of Tartu, Estonia and coordinated by Luca Pagani from the same institution and from the University of Padova, Italy.
"The genetic components we managed to extract from modern genomes are invaluable, given the shortage of ancient DNA available from South Asian human remains, and allow us to elucidate the genetic composition of the ancient populations that inhabited the area," said Burak Yelmen, co-first author of the study.
While studying the mixing events that brought ancient human populations to form contemporary South Asians, the researchers also noted that some portion of the genomes had not mixed as expected, as if the genetic variants that evolved in South Asia or the ones that arrived from West Eurasia were important for adapting to the local lifestyle through admixture.
"Among these variants, we found genes important for immunity and for dietary changes, as one may expect for human populations adapting to new sets of pathogens or food," said Mayukh Mondal, joint first author of this work.
The human evolution of skin pigmentation also revealed many genetic variants for the population studied.
"Intriguingly we also noted that some genetic variants implicated in the skin pigmentation of West Eurasians were under opposite selective forces, some becoming highly frequent and others being almost lost after the admixture events. Skin pigmentation is surely a fascinating and complex subject and we are still trying to understand what, if any, would be the adaptive implications of the signal we detected."
The study will add to the growing picture of the diversity of South Asians, and future studies of modern human population origins.
Read more at Science Daily
Apr 6, 2019
Large Antarctic Ice Shelf, home to a UK research station, is about to break apart
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| This is the Halloween Crack, which was discovered on 31 October 2016. |
The rifting started several years ago and is now approaching its final phase. In anticipation of the iceberg breaking away, the research station, which is currently unmanned, has been relocated to a safer location on the ice shelf, meaning there is no danger posed to personnel.
The iceberg, measuring over 1,500 square kilometres -- which is twice the size of New York City -- is expected to break away from the Brunt Ice Shelf in as little as a few months, when two large cracks which have been growing over the past seven years meet.
Now academics from Northumbria University, in Newcastle upon Tyne, UK, in collaboration with scientists from ENVEO, a remote sensing company in Austria, have submitted new research to the journal The Cryosphere, which shows that the break-off is part of the ice shelf's natural lifecycle, and that similar events may have occurred in the past.
As Professor Hilmar Gudmundsson of Northumbria explains: "I have been carrying out research in this area for more than 15 years and have been monitoring the growth of the cracks since they first emerged in 2012.
"Satellite images of the changes in the ice shelf have been shared online and there has been much speculation about the cause of this movement and the impact the iceberg will have when it breaks away.
"However, what many people do not realise is that this is a natural process and something which has happened time and again. We recognise that climate change is a serious problem which is having an impact around the world, and particularly in the Antarctic. However, there is no indication from our research that this particular event is related to climate change.
"We have been tracking the movement of the ice shelf for many years and our modelling indicates that this breakaway is entirely expected. That is why in 2014 we recommended that the Halley Research Station was moved to a new and safe location on the ice shelf.
"Our field observations and modelling has meant that the station was safely relocated with no danger to the scientists using it and minimal disruption to the research taking place."
The Brunt Ice Shelf is a large floating area of ice, around 150m to 250m thick, and is made up of freshwater ice which originally fell as snow further inland. The ice shelf rests on top of the Weddell Sea and flows off the mainland, moving outwards from the centre of Antarctica.
As ice shelves are afloat, any icebergs that form as a result of fractures in the ice do not contribute to sea level rise. "Once the iceberg breaks away from the Brunt Ice Shelf it is likely to drift towards the west and slowly break up into smaller icebergs," explains Dr Jan De Rydt, also of Northumbria University.
This isn't the first time a large piece of ice shelf has broken away in Antarctica. The Pine Island Ice Shelf in West Antarctica has seen several large sections break off in recent years, and the Larsen C Ice Shelf to the West of the Brunt Ice Shelf has lost a section more than 3,600 square miles due to calving -- when ice chunks break from the edge of a glacier -- in 2017.
And there is historic evidence to show the Brunt Ice Shelf has seen similar large calving events in the past. As Professor Gudmundsson explains: "Maps drawn by Shackleton and Wordie during their expedition to the Brunt Ice Shelf in 1915 show that, at that time, the ice shelf was quite extended. However, by the time the Halley Research Station was established in the 1950s the reach of the ice shelf was much shorter, indicating that a large iceberg must have broken away at some point after 1915. This further backs up our research that this type of event is historically consistent and part of the natural cycle and movement of the ice shelf."
Dr De Rydt and Professor Gudmundsson's paper, Calving cycle of the Brunt Ice Shelf, Antarctica, driven by changes in ice-shelf geometry, is currently undergoing peer review in the European Geosciences Union journal The Cryosphere.
The paper is co-authored by Thomas Nagler and Jan Wuite of ENVEO (Environmental Earth Observation), in Innsbruck, Austria, who have worked closely with Professor Gudmundsson and Dr De Rydt during the research. ENVEO is a world-leader in processing satellite data for monitoring changes in the global snow and ice cover. The two teams have been collaborating together for several years on a number of projects, with scientists from ENVEO using satellite imagery to extract data about the changing speed of the ice shelf, which is then shared with researchers at Northumbria University for modelling and interpretation.
Dr Jan Wuite of ENVEO said: "Thanks to the Copernicus Sentinel-1 and Sentinel-2 satellites we can now continuously monitor the movement of the ice shelf and the propagation of the cracks in great detail and in near real-time. These observational data are very useful for improving existing ice flow models."
Read more at Science Daily
Unexpected rain on sun links two solar mysteries
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| Mason's article analyzed three observations of Raining Null-Point Topologies, or RNTPs, a previously overlooked magnetic structure shown here in two wavelengths of extreme ultraviolet light. The coronal rain observed in these comparatively small magnetic loops suggests that the corona may be heated within a far more restricted region than previously expected. |
Mason, a graduate student at The Catholic University of America in Washington, D.C., was searching for coronal rain: giant globs of plasma, or electrified gas, that drip from the Sun's outer atmosphere back to its surface. But she expected to find it in helmet streamers, the million-mile tall magnetic loops -- named for their resemblance to a knight's pointy helmet -- that can be seen protruding from the Sun during a solar eclipse. Computer simulations predicted the coronal rain could be found there. Observations of the solar wind, the gas escaping from the Sun and out into space, hinted that the rain might be happening. And if she could just find it, the underlying rain-making physics would have major implications for the 70-year-old mystery of why the Sun's outer atmosphere, known as the corona, is so much hotter than its surface. But after nearly half a year of searching, Mason just couldn't find it. "It was a lot of looking," Mason said, "for something that never ultimately happened."
The problem, it turned out, wasn't what she was looking for, but where. In a paper published today in the Astrophysical Journal Letters, Mason and her coauthors describe the first observations of coronal rain in a smaller, previously overlooked kind of magnetic loop on the Sun. After a long, winding search in the wrong direction, the findings forge a new link between the anomalous heating of the corona and the source of the slow solar wind -- two of the biggest mysteries facing solar science today.
How It Rains on the Sun
Observed through the high-resolution telescopes mounted on NASA's SDO spacecraft, the Sun -- a hot ball of plasma, teeming with magnetic field lines traced by giant, fiery loops -- seems to have few physical similarities with Earth. But our home planet provides a few useful guides in parsing the Sun's chaotic tumult: among them, rain.
On Earth, rain is just one part of the larger water cycle, an endless tug-of-war between the push of heat and pull of gravity. It begins when liquid water, pooled on the planet's surface in oceans, lakes, or streams, is heated by the Sun. Some of it evaporates and rises into the atmosphere, where it cools and condenses into clouds. Eventually, those clouds become heavy enough that gravity's pull becomes irresistible and the water falls back to Earth as rain, before the process starts anew.
On the Sun, Mason said, coronal rain works similarly, "but instead of 60-degree water you're dealing with a million-degree plasma." Plasma, an electrically-charged gas, doesn't pool like water, but instead traces the magnetic loops that emerge from the Sun's surface like a rollercoaster on tracks. At the loop's foot points, where it attaches to the Sun's surface, the plasma is superheated from a few thousand to over 1.8 million degrees Fahrenheit. It then expands up the loop and gathers at its peak, far from the heat source. As the plasma cools, it condenses and gravity lures it down the loop's legs as coronal rain.
Mason was looking for coronal rain in helmet streamers, but her motivation for looking there had more to do with this underlying heating and cooling cycle than the rain itself. Since at least the mid-1990s, scientists have known that helmet streamers are one source of the slow solar wind, a comparatively slow, dense stream of gas that escapes the Sun separately from its fast-moving counterpart. But measurements of the slow solar wind gas revealed that it had once been heated to an extreme degree before cooling and escaping the Sun. The cyclical process of heating and cooling behind coronal rain, if it was happening inside the helmet streamers, would be one piece of the puzzle.
The other reason connects to the coronal heating problem -- the mystery of how and why the Sun's outer atmosphere is some 300 times hotter than its surface. Strikingly, simulations have shown that coronal rain only forms when heat is applied to the very bottom of the loop. "If a loop has coronal rain on it, that means that the bottom 10% of it, or less, is where coronal heating is happening," said Mason. Raining loops provide a measuring rod, a cutoff point to determine where the corona gets heated. Starting their search in the largest loops they could find -- giant helmet streamers -- seemed like a modest goal, and one that would maximize their chances of success.
She had the best data for the job: Images taken by NASA's Solar Dynamics Observatory, or SDO, a spacecraft that has photographed the Sun every twelve seconds since its launch in 2010. But nearly half a year into the search, Mason still hadn't observed a single drop of rain in a helmet streamer. She had, however, noticed a slew of tiny magnetic structures, ones she wasn't familiar with. "They were really bright and they kept drawing my eye," said Mason. "When I finally took a look at them, sure enough they had tens of hours of rain at a time."
At first, Mason was so focused on her helmet streamer quest that she made nothing of the observations. "She came to group meeting and said, 'I never found it -- I see it all the time in these other structures, but they're not helmet streamers,'" said Nicholeen Viall, a solar scientist at Goddard, and a coauthor of the paper. "And I said, 'Wait...hold on. Where do you see it? I don't think anybody's ever seen that before!'"
A Measuring Rod for Heating
These structures differed from helmet streamers in several ways. But the most striking thing about them was their size.
"These loops were much smaller than what we were looking for," said Spiro Antiochos, who is also a solar physicist at Goddard and a coauthor of the paper. "So that tells you that the heating of the corona is much more localized than we were thinking."
While the findings don't say exactly how the corona is heated, "they do push down the floor of where coronal heating could happen," said Mason. She had found raining loops that were some 30,000 miles high, a mere two percent the height of some of the helmet streamers she was originally looking for. And the rain condenses the region where the key coronal heating can be happening. "We still don't know exactly what's heating the corona, but we know it has to happen in this layer," said Mason.
A New Source for the Slow Solar Wind
But one part of the observations didn't jibe with previous theories. According to the current understanding, coronal rain only forms on closed loops, where the plasma can gather and cool without any means of escape. But as Mason sifted through the data, she found cases where rain was forming on open magnetic field lines. Anchored to the Sun at only one end, the other end of these open field lines fed out into space, and plasma there could escape into the solar wind. To explain the anomaly, Mason and the team developed an alternative explanation -- one that connected rain on these tiny magnetic structures to the origins of the slow solar wind.
In the new explanation, the raining plasma begins its journey on a closed loop, but switches -- through a process known as magnetic reconnection -- to an open one. The phenomenon happens frequently on the Sun, when a closed loop bumps into an open field line and the system rewires itself. Suddenly, the superheated plasma on the closed loop finds itself on an open field line, like a train that has switched tracks. Some of that plasma will rapidly expand, cool down, and fall back to the Sun as coronal rain. But other parts of it will escape -- forming, they suspect, one part of the slow solar wind.
Mason is currently working on a computer simulation of the new explanation, but she also hopes that soon-to-come observational evidence may confirm it. Now that Parker Solar Probe, launched in 2018, is traveling closer to the Sun than any spacecraft before it, it can fly through bursts of slow solar wind that can be traced back to the Sun -- potentially, to one of Mason's coronal rain events. After observing coronal rain on an open field line, the outgoing plasma, escaping to the solar wind, would normally be lost to posterity. But no longer. "Potentially we can make that connection with Parker Solar Probe and say, that was it," said Viall.
Digging Through the Data
As for finding coronal rain in helmet streamers? The search continues. The simulations are clear: the rain should be there. "Maybe it's so small you can't see it?" said Antiochos. "We really don't know."
But then again, if Mason had found what she was looking for she might not have made the discovery -- or have spent all that time learning the ins and outs of solar data.
Read more at Science Daily
Apr 5, 2019
Like old photographs, memories fade over time
Like old photographs, memories fade in quality over time -- a surprising finding for a team of Boston College researchers who expected recollections would become less accurate, but found people also report declines in the vibrancy and visual qualities of their memories.
When people remember the past, they remember it with varying degrees of clarity, said Boston College Assistant Professor of Psychology Maureen Ritchey, a cognitive neuroscientist and co-author of the study, published in an online edition of the journal Psychological Science.
Sometimes people remember lots of details about an event, as if they are reliving the moment as it happened, said Ritchey. Other times, it seems like the memory has faded, and the details are fuzzy. Prior memory research has shown that emotionally significant events -- like a car accident -- are remembered more vividly than everyday events.
"We wanted to know whether this feeling of memory vividness is related to not just what is remembered, but how it is remembered -- the visual quality of the memory," said Ritchey, who conducted the study with Boston College Professor of Psychology Elizabeth Kensinger and post-doctoral researcher Rose Cooper.
As events are stored in memory or forgotten, the team asked, how do their visual features change? Ritchey said people reported changes to their memories akin to using a filter to edit a picture.
"A simple analogy is what happens when you post a photo on Instagram," Ritchey said. "You're cued to apply a filter that changes the brightness or color saturation of the image. In our study, we asked if forgetting is like applying a filter to past experience, and whether or not the emotional significance of the event would change which filter you apply."
In three experiments, participants studied emotionally negative and neutral images that varied in visual quality -- luminance and color saturation. They then reconstructed the visual qualities of each image in a subsequent test.
The findings revealed that memories were recollected as less visually vibrant than they were encoded, demonstrating a novel memory-fading effect, the researchers reported.
Negative emotions subjects experienced when viewing the images increased the likelihood that images would be accurately remembered but did not influence memory fading. In addition, subjective ratings of memory vividness were lower for less accurate memories and for memories that had visually faded, the team found.
These findings provide evidence that the vibrancy of low-level details -- such as colors and shapes associated with an event -- fade in memory while the gist of the experience is retained.
People may remember going to a music festival and watching their favorite band, but the intensity of that sensory experience, including the bright stage lights and strength of the bass, will slowly fade.
"We found that memories seem to literally fade: people consistently remembered visual scenes as being less vibrant than they were originally experienced," said Cooper. "We had expected that memories would get less accurate after a delay, but we did not expect that there would be this qualitative shift in the way that they were remembered."
The fading effect happened less for memories that were rated as subjectively stronger. "We were also surprised to find that emotional memories did not influence the amount of fading, only the likelihood with which people remembered the images at all," she added.
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When people remember the past, they remember it with varying degrees of clarity, said Boston College Assistant Professor of Psychology Maureen Ritchey, a cognitive neuroscientist and co-author of the study, published in an online edition of the journal Psychological Science.
Sometimes people remember lots of details about an event, as if they are reliving the moment as it happened, said Ritchey. Other times, it seems like the memory has faded, and the details are fuzzy. Prior memory research has shown that emotionally significant events -- like a car accident -- are remembered more vividly than everyday events.
"We wanted to know whether this feeling of memory vividness is related to not just what is remembered, but how it is remembered -- the visual quality of the memory," said Ritchey, who conducted the study with Boston College Professor of Psychology Elizabeth Kensinger and post-doctoral researcher Rose Cooper.
As events are stored in memory or forgotten, the team asked, how do their visual features change? Ritchey said people reported changes to their memories akin to using a filter to edit a picture.
"A simple analogy is what happens when you post a photo on Instagram," Ritchey said. "You're cued to apply a filter that changes the brightness or color saturation of the image. In our study, we asked if forgetting is like applying a filter to past experience, and whether or not the emotional significance of the event would change which filter you apply."
In three experiments, participants studied emotionally negative and neutral images that varied in visual quality -- luminance and color saturation. They then reconstructed the visual qualities of each image in a subsequent test.
The findings revealed that memories were recollected as less visually vibrant than they were encoded, demonstrating a novel memory-fading effect, the researchers reported.
Negative emotions subjects experienced when viewing the images increased the likelihood that images would be accurately remembered but did not influence memory fading. In addition, subjective ratings of memory vividness were lower for less accurate memories and for memories that had visually faded, the team found.
These findings provide evidence that the vibrancy of low-level details -- such as colors and shapes associated with an event -- fade in memory while the gist of the experience is retained.
People may remember going to a music festival and watching their favorite band, but the intensity of that sensory experience, including the bright stage lights and strength of the bass, will slowly fade.
"We found that memories seem to literally fade: people consistently remembered visual scenes as being less vibrant than they were originally experienced," said Cooper. "We had expected that memories would get less accurate after a delay, but we did not expect that there would be this qualitative shift in the way that they were remembered."
The fading effect happened less for memories that were rated as subjectively stronger. "We were also surprised to find that emotional memories did not influence the amount of fading, only the likelihood with which people remembered the images at all," she added.
Read more at Science Daily
Scientists discover first organism with chlorophyll genes that doesn't photosynthesize
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| Corallicolids are found in 70 percent of corals around the world. |
The peculiar organism is dubbed 'corallicolid' because it is found in 70 per cent of corals around the world and may provide clues as to how to protect coral reefs in the future.
"This is the second most abundant cohabitant of coral on the planet and it hasn't been seen until now," says Patrick Keeling, a University of British Columbia botanist and senior researcher overseeing the study published in Nature. "This organism poses completely new biochemical questions. It looks like a parasite, and it's definitely not photosynthetic. But it still makes chlorophyll."
Chlorophyll is the green pigment found in plants and algae that allows them to absorb energy from sunlight during photosynthesis.
"Having chlorophyll without photosynthesis is actually very dangerous because chlorophyll is very good at capturing energy, but without photosynthesis to release the energy slowly it is like living with a bomb in your cells," Keeling says.
Corallicolids live in the gastric cavity of a wide array of corals responsible for building reefs, as well as black corals, fan corals, mushroom corals, and anemones. They are an apicomplexan, part of a vast group of parasites that have a cellular compartment called a plastid, which is the part of plant and algal cells where photosynthesis takes place. The most famous apicomplexan is the parasite responsible for malaria.
More than a decade ago, photosynthetic algae related to apicomplexans were discovered in healthy corals, indicating they might have evolved from benign photosynthesising organisms attached to corals before turning into the parasites we know today.
Ecological data showed that coral reefs contain several apicomplexans, but corallicolids, the most most common one, had not been studied until now. The organism has revealed a new puzzle: not only does it have a plastid, but it contains all four plastid genes used in chlorophyll production.
"It's quite a head scratcher," says Waldan Kwong, a UBC postdoctoral research fellow and lead author of the study. "We don't know why these organisms are holding on to these photosynthesis genes. There's some novel biology going on here, something we haven't seen before."
Read more at Science Daily
Electricity-conducting bacteria yield secret to tiny batteries, big medical advances
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| An atomic model for the microbial nanowires that conduct electricity is in the foreground, while two bacteria are seen in the electron micrograph in the background, surrounded by the nanowires. |
Scientists had believed Geobacter sulfurreducens conducted electricity through common, hair-like appendages called pili. Instead, a researcher at the University of Virginia School of Medicine and his collaborators have determined that the bacteria transmit electricity through immaculately ordered fibers made of an entirely different protein. These proteins surround a core of metal-containing molecules, much like an electric cord contains metal wires. This "nanowire," however, is 100,000 times smaller than the width of a human hair.
This tiny-but-tidy structure, the researchers believe, could be tremendously useful for everything from harnessing the power of bioenergy to cleaning up pollution to creating biological sensors. It could actually serve as the bridge between electronics and living cells.
"There are all sorts of implanted medical devices that are connected to tissue, like pacemakers with wires, and this could lead to applications where you have miniature devices that are actually connected by these protein filaments," said UVA's Edward H. Egelman, PhD. "We can now imagine the miniaturization of many electronic devices generated by bacteria, which is pretty amazing."
Small but Effective
Geobacter bacteria play important roles in the soil, including facilitating mineral turnover and even cleaning up radioactive waste. They survive in environments without oxygen, and they use nanowires to rid themselves of excess electrons in what can be considered their equivalent to breathing. These nanowires have fascinated scientists, but it is only now that researchers at UVA, Yale and the University of California, Irvine, have been able to determine how G. sulfurreducens uses these organic wires to transmit electricity.
"The technology [to understand nanowires] didn't exist until about five years ago, when advances in cryo-electron microscopy allowed high resolution," said Egelman, of UVA's Department of Biochemistry and Molecular Genetics. "We have one of these instruments here at UVA, and, therefore, the ability to actually understand at the atomic level the structure of these filaments. ... So this is just one of the many mysteries that we've now been able to solve using this technology, like the virus that can survive in boiling acid, and there will be others."
Read more at Science Daily
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