Whether there is life elsewhere in the universe is a question people have pondered for millennia; and within the last few decades, great strides have been made in our search for signs of life outside of our solar system.
NASA missions like the space telescope Kepler have helped us document thousands of exoplanets -- planets that orbit around other stars. And current NASA missions like Transiting Exoplanet Survey Satellite (TESS) are expected to vastly increase the current number of known exoplanets. It is expected that dozens will be Earth-sized rocky planets orbiting in their stars' habitable zones, at distances where water could exist as a liquid on their surfaces. These are promising places to look for life.
This will be accomplished by missions like the soon-to-be-launched James Webb Space Telescope, which will complement and extend the discoveries of the Hubble Space Telescope by observing at infrared wavelengths. It is expected to launch in 2021, and will allow scientists to determine if rocky exoplanets have oxygen in their atmospheres. Oxygen in Earth's atmosphere is due to photosynthesis by microbes and plants. To the extent that exoplanets resemble Earth, oxygen in their atmospheres may also be a sign of life.
Not all exoplanets will be Earth-like, though. Some will be, but others will differ from Earth enough that oxygen doesn't necessarily come from life. So with all of these current and future exoplanets to study, how do scientists narrow down the field to those for which oxygen is most indicative of life?
To answer this question, an interdisciplinary team of researchers, led by Arizona State University (ASU), has provided a framework, called a "detectability index" which may help prioritize exoplanets that require additional study. The details of this index have recently been published in the Astrophysical Journal of the American Astronomical Society.
"The goal of the index is to provide scientists with a tool to select the very best targets for observation and to maximize the chances of detecting life," says lead author Donald Glaser of ASU's School of Molecular Sciences.
The oxygen detectability index for a planet like Earth is high, meaning that oxygen in Earth's atmosphere is definitely due to life and nothing else. Seeing oxygen means life. A surprising finding by the team is that the detectability index plummets for exoplanets not-too-different from Earth.
Although Earth's surface is largely covered in water, Earth's oceans are only a small percentage (0.025%) of Earth's mass. By comparison, moons in the outer solar system are typically close to 50% water ice.
"It's easy to imagine that in another solar system like ours, an Earth-like planet could be just 0.2% water," says co-author Steven Desch of ASU's School of Earth and Space Exploration. "And that would be enough to change the detectability index. Oxygen would not be indicative of life on such planets, even if it were observed. That's because an Earth-like planet that was 0.2% water -- about eight times what Earth has -- would have no exposed continents or land."
Without land, rain would not weather rock and release important nutrients like phosphorus. Photosynthetic life could not produce oxygen at rates comparable to other non-biological sources.
"The detectability index tells us it's not enough to observe oxygen in an exoplanet's atmosphere. We must also observe oceans and land," says Desch. "That changes how we approach the search for life on exoplanets. It helps us interpret observations we've made of exoplanets. It helps us pick the best target exoplanets to look for life on. And it helps us design the next generation of space telescopes so that we get all the information we need to make a positive identification of life."
Scientists from diverse fields were brought together to create this index. The formation of the team was facilitated by NASA's Nexus for Exoplanetary System Science (NExSS) program, which funds interdisciplinary research to develop strategies for looking for life on exoplanets. Their disciplines include theoretical and observational astrophysics, geophysics, geochemistry, astrobiology, oceanography, and ecology.
"This kind of research needs diverse teams, we can't do it as individual scientists" says co-author Hilairy Hartnett who holds joint appointments at ASU's School of Earth and Space Exploration and School of Molecular Sciences.
In addition to lead author Glaser and co-authors Harnett and Desch, the team includes co-authors Cayman Unterborn, Ariel Anbar, Steffen Buessecker, Theresa Fisher, Steven Glaser, Susanne Neuer, Camerian Millsaps, Joseph O'Rourke, Sara Imari Walker, and Mikhail Zolotov who collectively represent ASU's School of Molecular Sciences, School of Earth and Space Exploration, and School of Life Sciences. Additional scientists on the team include researchers from the University of California Riverside, Johns Hopkins University and the University of Porto (Portugal).
Read more at Science Daily
May 5, 2020
Genetic study ties higher alcohol consumption to increased stroke and PAD risk
Higher alcohol consumption was shown to be associated with an increased risk of having a stroke or developing peripheral artery disease, according to new research published today in Circulation: Genomic and Precision Medicine, an American Heart Association journal.
While observational studies have consistently shown that heavy alcohol consumption is associated with an increased risk of certain cardiovascular diseases, they often use self-reported data and are unable to determine cause. Researchers in this study used a different technique called Mendelian randomization that identifies genetic variants with a known association to potential risk factors to determine the potential degree of disease risk.
"Since genetic variants are determined at conception and cannot be affected by subsequent environmental factors, this technique allows us to better determine whether a risk factor -- in this case, heavy alcohol consumption -- is the cause of a disease, or if it is simply associated," said Susanna Larsson, Ph.D., senior researcher and associate professor of cardiovascular and nutritional epidemiology at Karolinska Institutet in Stockholm, Sweden. "To our knowledge, this is the first Mendelian randomization study on alcohol consumption and several cardiovascular diseases."
Researchers analyzed the genetic data from several large-scale consortia and the UK Biobank, which follows the health and well-being of 500,000 United Kingdom residents. Results indicate that with higher alcohol consumption:
"Higher alcohol consumption is a known cause of death and disability, yet it was previously unclear if alcohol consumption is also a cause of cardiovascular disease. Considering that many people consume alcohol regularly, it is important to disentangle any risks or benefits," Larsson said.
Researchers noted that this study suggested the mechanism by which higher consumption was associated with the risk of stroke and PAD may be blood pressure.
According to a statement on dietary health, the American Heart Association believes that alcohol intake can be a component of a healthy diet if consumed in moderation (no more than one alcoholic drink per day for women and 2 alcohol drinks per day for men) and only by nonpregnant women and adults when there is no risk to existing health conditions, medication-alcohol interaction, or personal safety and work situations. One drink is equivalent to 12 ounces of beer (5% alcohol); 5 ounces of wine (12% alcohol); or 1.5 ounces of 80-proof distilled spirits (40% alcohol).
Read more at Science Daily
While observational studies have consistently shown that heavy alcohol consumption is associated with an increased risk of certain cardiovascular diseases, they often use self-reported data and are unable to determine cause. Researchers in this study used a different technique called Mendelian randomization that identifies genetic variants with a known association to potential risk factors to determine the potential degree of disease risk.
"Since genetic variants are determined at conception and cannot be affected by subsequent environmental factors, this technique allows us to better determine whether a risk factor -- in this case, heavy alcohol consumption -- is the cause of a disease, or if it is simply associated," said Susanna Larsson, Ph.D., senior researcher and associate professor of cardiovascular and nutritional epidemiology at Karolinska Institutet in Stockholm, Sweden. "To our knowledge, this is the first Mendelian randomization study on alcohol consumption and several cardiovascular diseases."
Researchers analyzed the genetic data from several large-scale consortia and the UK Biobank, which follows the health and well-being of 500,000 United Kingdom residents. Results indicate that with higher alcohol consumption:
- a three-fold increase of peripheral artery disease, a narrowing of arteries that results in reduced blood flow, usually to the legs;
- a 27% increase in stroke incidence; and
- some evidence for a positive association of coronary artery disease, atrial fibrillation and aortic aneurysm.
"Higher alcohol consumption is a known cause of death and disability, yet it was previously unclear if alcohol consumption is also a cause of cardiovascular disease. Considering that many people consume alcohol regularly, it is important to disentangle any risks or benefits," Larsson said.
Researchers noted that this study suggested the mechanism by which higher consumption was associated with the risk of stroke and PAD may be blood pressure.
According to a statement on dietary health, the American Heart Association believes that alcohol intake can be a component of a healthy diet if consumed in moderation (no more than one alcoholic drink per day for women and 2 alcohol drinks per day for men) and only by nonpregnant women and adults when there is no risk to existing health conditions, medication-alcohol interaction, or personal safety and work situations. One drink is equivalent to 12 ounces of beer (5% alcohol); 5 ounces of wine (12% alcohol); or 1.5 ounces of 80-proof distilled spirits (40% alcohol).
Read more at Science Daily
Evidence that human brains replay our waking experiences while we sleep
When we fall asleep, our brains are not merely offline, they're busy organizing new memories -- and now, scientists have gotten a glimpse of the process. Researchers report in the journal Cell Reports on May 5 the first direct evidence that human brains replay waking experiences while asleep, seen in two participants with intracortical microelectrode arrays placed in their brains as part of a brain-computer interface pilot clinical trial.
During sleep, the brain replays neural firing patterns experienced while awake, also known as "offline replay." Replay is thought to underlie memory consolidation, the process by which recent memories acquire more permanence in their neural representation. Scientists have previously observed replay in animals, but the study led by Jean-Baptiste Eichenlaub of Massachusetts General Hospital and Beata Jarosiewicz, formerly Research Assistant Professor at BrainGate, and now Senior Research Scientist at NeuroPace, tested whether the phenomenon happens in human brains as well.
The team asked the two participants to take a nap before and after playing a sequence-copying game, which is similar to the 80s hit game Simon. The video game had four color panels that lit up in different sequences for the players to repeat. But instead of moving their arms, the participants played the game with their minds -- imagining moving the cursor with their hands to different targets one by one, hitting the correct colors in the correct order as quickly as possible. While the participants rested, played the game, and then rested again, the researchers recorded the spiking activity of large groups of individual neurons in their brains through an implanted multi-electrode array.
"There aren't a lot of scenarios in which a person would have a multi-electrode array placed in their brain, where the electrodes are tiny enough to be able to detect the firing activity of individual neurons," says co-first author Jarosiewicz. Electrodes approved for medical indications, like those for treating Parkinson's disease or epilepsy, are too big to track the spiking activity of single neurons. But the electrode arrays used in the BrainGate pilot clinical trials are the first to allow for such detailed neural recordings in the human brain. "That's why this study is unprecedented," she says.
BrainGate is an academic research consortium spanning Brown University, Massachusetts General Hospital, Case Western Reserve University, and Stanford University. Researchers at BrainGate are working to develop chronically implanted brain-computer interfaces to help people with severe motor disabilities regain communication and control by using their brain signals to move computer cursors, robotic arms, and other assistive devices.
In this study, the team observed the same neuronal firing patterns during both the gaming period and the post-game rest period. In other words, it's as though the participants kept playing the Simon game after they were asleep, replaying the same patterns in their brain at a neuronal level. The findings provided direct evidence of learning-related replay in the human brain.
"This is the first piece of direct evidence that in humans, we also see replay during rest following learning that might help to consolidate those memories," said Jarosiewicz. "All the replay-related memory consolidation mechanisms that we've studied in animals for all these decades might actually generalize to humans as well."
The findings also open up more questions and future topics of study who want to understand the underlying mechanism by which replay enables memory consolidation. The next step is to find evidence that replay actually has a causal role in the memory consolidation process. One way to do that would be to test whether there's a relationship between the strength of the replay and the strength of post-nap memory recall.
Read more at Science Daily
During sleep, the brain replays neural firing patterns experienced while awake, also known as "offline replay." Replay is thought to underlie memory consolidation, the process by which recent memories acquire more permanence in their neural representation. Scientists have previously observed replay in animals, but the study led by Jean-Baptiste Eichenlaub of Massachusetts General Hospital and Beata Jarosiewicz, formerly Research Assistant Professor at BrainGate, and now Senior Research Scientist at NeuroPace, tested whether the phenomenon happens in human brains as well.
The team asked the two participants to take a nap before and after playing a sequence-copying game, which is similar to the 80s hit game Simon. The video game had four color panels that lit up in different sequences for the players to repeat. But instead of moving their arms, the participants played the game with their minds -- imagining moving the cursor with their hands to different targets one by one, hitting the correct colors in the correct order as quickly as possible. While the participants rested, played the game, and then rested again, the researchers recorded the spiking activity of large groups of individual neurons in their brains through an implanted multi-electrode array.
"There aren't a lot of scenarios in which a person would have a multi-electrode array placed in their brain, where the electrodes are tiny enough to be able to detect the firing activity of individual neurons," says co-first author Jarosiewicz. Electrodes approved for medical indications, like those for treating Parkinson's disease or epilepsy, are too big to track the spiking activity of single neurons. But the electrode arrays used in the BrainGate pilot clinical trials are the first to allow for such detailed neural recordings in the human brain. "That's why this study is unprecedented," she says.
BrainGate is an academic research consortium spanning Brown University, Massachusetts General Hospital, Case Western Reserve University, and Stanford University. Researchers at BrainGate are working to develop chronically implanted brain-computer interfaces to help people with severe motor disabilities regain communication and control by using their brain signals to move computer cursors, robotic arms, and other assistive devices.
In this study, the team observed the same neuronal firing patterns during both the gaming period and the post-game rest period. In other words, it's as though the participants kept playing the Simon game after they were asleep, replaying the same patterns in their brain at a neuronal level. The findings provided direct evidence of learning-related replay in the human brain.
"This is the first piece of direct evidence that in humans, we also see replay during rest following learning that might help to consolidate those memories," said Jarosiewicz. "All the replay-related memory consolidation mechanisms that we've studied in animals for all these decades might actually generalize to humans as well."
The findings also open up more questions and future topics of study who want to understand the underlying mechanism by which replay enables memory consolidation. The next step is to find evidence that replay actually has a causal role in the memory consolidation process. One way to do that would be to test whether there's a relationship between the strength of the replay and the strength of post-nap memory recall.
Read more at Science Daily
Antibody blocks infection by the SARS-CoV-2 in cells, scientists discover
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| SARS-CoV-2 concept illustration |
The COVID-19 pandemic has spread rapidly across the globe infecting more than 3.3M people worldwide and killing more than 235,000 people so far.
"This research builds on the work our groups have done in the past on antibodies targeting the SARS-CoV that emerged in 2002/2003," said Berend-Jan Bosch, Associate Professor, Research leader at Utrecht University, and co-lead author of the Nature Communications study. "Using this collection of SARS-CoV antibodies, we identified an antibody that also neutralizes infection of SARS-CoV-2 in cultured cells. Such a neutralizing antibody has potential to alter the course of infection in the infected host, support virus clearance or protect an uninfected individual that is exposed to the virus."
Dr. Bosch noted that the antibody binds to a domain that is conserved in both SARS-CoV and SARS-CoV-2, explaining its ability to neutralize both viruses. "This cross-neutralizing feature of the antibody is very interesting and suggests it may have potential in mitigation of diseases caused by future-emerging related coronaviruses."
"This discovery provides a strong foundation for additional research to characterize this antibody and begin development as a potential COVID-19 treatment," said Frank Grosveld, PhD. co-lead author on the study, Academy Professor of Cell Biology, Erasmus Medical Center, Rotterdam and Founding Chief Scientific Officer at Harbour BioMed. "The antibody used in this work is 'fully human,' allowing development to proceed more rapidly and reducing the potential for immune-related side effects." Conventional therapeutic antibodies are first developed in other species and then must undergo additional work to 'humanize' them. The antibody was generated using Harbour BioMed's H2L2 transgenic mouse technology.
"This is groundbreaking research," said Dr. Jingsong Wang, Founder, Chairman & Chief Executive Officer of HBM. "Much more work is needed to assess whether this antibody can protect or reduce the severity of disease in humans. We expect to advance development of the antibody with partners. We believe our technology can contribute to addressing this most urgent public health need and we are pursuing several other research avenues."
Read more at Science Daily
May 4, 2020
Arctic 'shorefast' sea ice threatened by climate change
For people who live in the Arctic, sea ice that forms along shorelines is a vital resource that connects isolated communities and provides access to hunting and fishing grounds. A new study by Brown University researchers found that climate change could significantly reduce this "shorefast ice" in communities across Northern Canada and Western Greenland.
The study, published in Nature Climate Change, used weather data and near-daily satellite observations of 28 Arctic communities to determine the timing of shorefast ice breakup in each location over the past 19 years. The analysis enabled the researchers to determine the conditions that drive springtime ice breakup. Then they use climate models to predict how that timing might change in each community as the planet warms.
The analysis found that by 2100, communities could see shorefast ice seasons reduced by anywhere from five to 44 days, with the coldest communities in the study seeing the largest reductions. The wide range of potential outcomes was a surprise, the researchers say, and underscores the need to take local factors into account when making policy to prepare for future climate change.
"One of the key takeaways for me is that even though the whole Arctic is going to warm and lose ice, we see very different outcomes from one community to another," said Sarah Cooley, lead author of the study and a Ph.D. student in the Institute at Brown for Environment and Society (IBES). "When you combine that wide range of outcomes with the fact that different communities have lots of social, cultural and economic differences, it means that some communities may experience much larger impacts than others."
For example, the northern Canadian communities of Clyde River and Taloyoak, which are particularly dependent upon shorefast ice for subsistence hunting and fishing, will see some of the most substantial declines in sea ice. On average, these two communities can expect ice to break up 23 to 44 days earlier, respectively by 2100. That could mean "economically and culturally significant activities on the ice will be harder to maintain in the future," the researchers write.
That the coldest regions in the study could see the largest reductions in ice is cause for concern, says study co-author Johnny Ryan, a postdoctoral researcher at IBES.
"Some of these places are considered to be the last remnants of truly polar ecosystems and people talk a lot about preserving these areas in particular," Ryan said. "Yet these are the areas that we find will lose the most ice."
The research is part of a larger research effort aimed at better understanding how climate change in the Arctic will impact the people who live there. In addition to gathering satellite and scientific data, the research team conducted fieldwork in the community of Uummannaq in western Greenland to learn more about how the local population utilizes the ice.
"Shorefast ice is something that's most important from the standpoint of the people who use it," Cooley said. "It has some implications in terms of global climate, but those are fairly small. This is really all about how it affects the people who actually live in the Arctic, and that's why we're studying it."
The fieldwork also provided a first-hand perspective of how things have been changing over the years.
"One of the most powerful things that came out of the field study for me was listening to a hunter talk about how the ice is breaking up earlier than it ever has in his lifetime," Ryan said. "We're only observing this 20-year satellite record. But to be able to learn from locals about what things were like 50 or 60 years ago, it really emphasized how climate change has already impacted the community."
Moving forward, the research team is hopeful that mapping the local effects of regional and global climate patterns will be useful for policy-makers.
Read more at Science Daily
The study, published in Nature Climate Change, used weather data and near-daily satellite observations of 28 Arctic communities to determine the timing of shorefast ice breakup in each location over the past 19 years. The analysis enabled the researchers to determine the conditions that drive springtime ice breakup. Then they use climate models to predict how that timing might change in each community as the planet warms.
The analysis found that by 2100, communities could see shorefast ice seasons reduced by anywhere from five to 44 days, with the coldest communities in the study seeing the largest reductions. The wide range of potential outcomes was a surprise, the researchers say, and underscores the need to take local factors into account when making policy to prepare for future climate change.
"One of the key takeaways for me is that even though the whole Arctic is going to warm and lose ice, we see very different outcomes from one community to another," said Sarah Cooley, lead author of the study and a Ph.D. student in the Institute at Brown for Environment and Society (IBES). "When you combine that wide range of outcomes with the fact that different communities have lots of social, cultural and economic differences, it means that some communities may experience much larger impacts than others."
For example, the northern Canadian communities of Clyde River and Taloyoak, which are particularly dependent upon shorefast ice for subsistence hunting and fishing, will see some of the most substantial declines in sea ice. On average, these two communities can expect ice to break up 23 to 44 days earlier, respectively by 2100. That could mean "economically and culturally significant activities on the ice will be harder to maintain in the future," the researchers write.
That the coldest regions in the study could see the largest reductions in ice is cause for concern, says study co-author Johnny Ryan, a postdoctoral researcher at IBES.
"Some of these places are considered to be the last remnants of truly polar ecosystems and people talk a lot about preserving these areas in particular," Ryan said. "Yet these are the areas that we find will lose the most ice."
The research is part of a larger research effort aimed at better understanding how climate change in the Arctic will impact the people who live there. In addition to gathering satellite and scientific data, the research team conducted fieldwork in the community of Uummannaq in western Greenland to learn more about how the local population utilizes the ice.
"Shorefast ice is something that's most important from the standpoint of the people who use it," Cooley said. "It has some implications in terms of global climate, but those are fairly small. This is really all about how it affects the people who actually live in the Arctic, and that's why we're studying it."
The fieldwork also provided a first-hand perspective of how things have been changing over the years.
"One of the most powerful things that came out of the field study for me was listening to a hunter talk about how the ice is breaking up earlier than it ever has in his lifetime," Ryan said. "We're only observing this 20-year satellite record. But to be able to learn from locals about what things were like 50 or 60 years ago, it really emphasized how climate change has already impacted the community."
Moving forward, the research team is hopeful that mapping the local effects of regional and global climate patterns will be useful for policy-makers.
Read more at Science Daily
When natural disasters strike locally, urban networks spread the damage globally
When cyclones and other natural disasters strike a city or town, the social and economic impacts locally can be devastating. But these events also have ripple effects that can be felt in distant cities and regions -- even globally -- due to the interconnectedness of the world's urban trade networks.
In fact, a new study by researchers at the Yale School of Forestry & Environmental Studies finds that local economic impacts -- such as damage to factories and production facilities -- can trigger secondary impacts across the city's production and trade network. For the largest storms, they report, these impacts can account for as much as three-fourths of the total damage.
According to their findings, published in the journal Nature Sustainability, the extent of these secondary costs depends more on the structure of the production and supply networks for a particular city than on its geographic location. Regional cities that are dependent on their urban network for industrial supplies -- and that have access to relatively few suppliers -- are most vulnerable to these secondary impacts. Larger, global cities such as New York and Beijing, meanwhile, are more insulated from risks.
"Cities are strongly connected by flows of people, of energy, and ideas -- but also by the flows of trade and materials," said Chris Shughrue '18 Ph.D., lead author of the study which is based on his dissertation work at Yale. He is now a data scientist at StreetCred Labs in New York. "These connections have implications for vulnerability, particularly as we anticipate cyclones and other natural hazards to become more intense and frequent as a result of climate change over the coming decades."
The paper was co-authored by Karen Seto, a professor of geography and urbanization science at F&ES, and B.T. Werner, a professor from the Scripps Institution of Oceanography.
"This study is especially important in the context of climate impacts on urban areas," Seto said. "Whereas we tend to consider a city's vulnerability to climate change as limited to local events, this study shows that we need to rethink this conceptualization. It shows that disasters have a domino effect through urban networks."
Using a simulation coupled with a global urban trade network model -- which maps the interdependencies of cities worldwide -- the researchers show how simulated disasters in one location can trigger a catastrophic domino effect.
The global spread of damage was particularly acute when cyclones occurred in cities of North America and East Asia, largely because of their outsize role in global trade networks -- as purchasers and suppliers, respectively -- and because these regions are particularly susceptible to cyclone events.
Often, adverse impacts are primarily caused by a spike in material prices, followed by production losses to purchasers. These production losses eventually can cause industrial shortages, which can then induce additional cycles of price spikes and shortages throughout the production chain.
Similar outcomes have been borne out following real world disasters. For instance, when catastrophic flooding occurred in Queensland, Australia, the impact on coking coal production prompted a 25-percent spike in the global costs. And the economic impacts of Hurricane Katrina extended far beyond New Orleans for several years after the historic storm.
While the example of cyclones can act as a proxy for other isolated disasters -- such as the 2011 tsunami in Japan which caused global economic disruptions, particularly in the auto sector -- the researchers say the findings are particularly relevant in terms of climate-related natural events.
Read more at Science Daily
In fact, a new study by researchers at the Yale School of Forestry & Environmental Studies finds that local economic impacts -- such as damage to factories and production facilities -- can trigger secondary impacts across the city's production and trade network. For the largest storms, they report, these impacts can account for as much as three-fourths of the total damage.
According to their findings, published in the journal Nature Sustainability, the extent of these secondary costs depends more on the structure of the production and supply networks for a particular city than on its geographic location. Regional cities that are dependent on their urban network for industrial supplies -- and that have access to relatively few suppliers -- are most vulnerable to these secondary impacts. Larger, global cities such as New York and Beijing, meanwhile, are more insulated from risks.
"Cities are strongly connected by flows of people, of energy, and ideas -- but also by the flows of trade and materials," said Chris Shughrue '18 Ph.D., lead author of the study which is based on his dissertation work at Yale. He is now a data scientist at StreetCred Labs in New York. "These connections have implications for vulnerability, particularly as we anticipate cyclones and other natural hazards to become more intense and frequent as a result of climate change over the coming decades."
The paper was co-authored by Karen Seto, a professor of geography and urbanization science at F&ES, and B.T. Werner, a professor from the Scripps Institution of Oceanography.
"This study is especially important in the context of climate impacts on urban areas," Seto said. "Whereas we tend to consider a city's vulnerability to climate change as limited to local events, this study shows that we need to rethink this conceptualization. It shows that disasters have a domino effect through urban networks."
Using a simulation coupled with a global urban trade network model -- which maps the interdependencies of cities worldwide -- the researchers show how simulated disasters in one location can trigger a catastrophic domino effect.
The global spread of damage was particularly acute when cyclones occurred in cities of North America and East Asia, largely because of their outsize role in global trade networks -- as purchasers and suppliers, respectively -- and because these regions are particularly susceptible to cyclone events.
Often, adverse impacts are primarily caused by a spike in material prices, followed by production losses to purchasers. These production losses eventually can cause industrial shortages, which can then induce additional cycles of price spikes and shortages throughout the production chain.
Similar outcomes have been borne out following real world disasters. For instance, when catastrophic flooding occurred in Queensland, Australia, the impact on coking coal production prompted a 25-percent spike in the global costs. And the economic impacts of Hurricane Katrina extended far beyond New Orleans for several years after the historic storm.
While the example of cyclones can act as a proxy for other isolated disasters -- such as the 2011 tsunami in Japan which caused global economic disruptions, particularly in the auto sector -- the researchers say the findings are particularly relevant in terms of climate-related natural events.
Read more at Science Daily
Predators help prey adapt to an uncertain future
What effect does extinction of species have on the evolution of surviving species? Evolutionary biologists have investigated this question by conducting a field experiment with a leaf galling fly and its predatory enemies. They found that losing its natural enemies could make it more difficult for the prey to adapt to future environments.
According to many experts, the Earth is at the beginning of its sixth mass extinction, which is already having dire consequences for the functioning of natural ecosystems. What remains unclear is how these extinctions will alter the future ability of remaining species to adapt.
Researchers from the University of Zurich have now pursued this question with a field experiment in California. They investigated how the traits of a tiny fly changed when a group of its natural enemies was removed. From their observations, they drew conclusions about changes in the genetic diversity of the flies.
Specific elimination of parasitoids
The fly Iteomyia salicisverruca lives on willow leaves in tooth-shaped growths called galls, which it induces in its larval stage. The natural enemies of this fly include several species of parasitic wasps. These wasps lay their eggs inside the fly larva within the gall, where they then develop into parasitic predators known as parasitoids. Before the adult wasp leaves the gall, it devours its host, the fly.
Some species of these parasitoids attack before the gall is formed, while others parasitize fly larvae later in their development and pierce through the gall. The researchers specifically eliminated the latter group of natural enemies by attaching fine-meshed nets over leaves with galls before they were attacked.
After three months, the biologists collected about 600 galls and checked if the fly larvae had survived. They also measured three traits that influence a fly's survival from parasitoid attack: the size of the gall; the number of flies within a gall; and the fly's preference to create galls on particular genetic varieties of willow trees. Using these data they then created "fitness landscapes" using computer models, which visualize the adaptability of a species.
Fewer enemies, less variability
It turned out that different combinations of these three traits helped flies survive ? when all of the fly's natural enemies were present. "So there are several equally good solutions that ensure the survival of the fly," says Matt Barbour, the study's lead author. In contrast, after some natural enemies were removed, only one specific combination of traits helped flies survive. "This suggests that the extinction of natural enemies constrains fly evolution toward only one optimal solution." Genetic variations that lead to a different development of the traits could thus be permanently lost in the flies' genome.
This loss of diversity might be of consequence: "The diversity of potential solutions for survival acts to preserve genetic variability in the gall's traits," says Barbour. And since genetic variation provides the raw material for evolution, the findings suggest that the extinction of this fly's natural enemies may make it more difficult for it to adapt to a changing environment.
Read more at Science Daily
According to many experts, the Earth is at the beginning of its sixth mass extinction, which is already having dire consequences for the functioning of natural ecosystems. What remains unclear is how these extinctions will alter the future ability of remaining species to adapt.
Researchers from the University of Zurich have now pursued this question with a field experiment in California. They investigated how the traits of a tiny fly changed when a group of its natural enemies was removed. From their observations, they drew conclusions about changes in the genetic diversity of the flies.
Specific elimination of parasitoids
The fly Iteomyia salicisverruca lives on willow leaves in tooth-shaped growths called galls, which it induces in its larval stage. The natural enemies of this fly include several species of parasitic wasps. These wasps lay their eggs inside the fly larva within the gall, where they then develop into parasitic predators known as parasitoids. Before the adult wasp leaves the gall, it devours its host, the fly.
Some species of these parasitoids attack before the gall is formed, while others parasitize fly larvae later in their development and pierce through the gall. The researchers specifically eliminated the latter group of natural enemies by attaching fine-meshed nets over leaves with galls before they were attacked.
After three months, the biologists collected about 600 galls and checked if the fly larvae had survived. They also measured three traits that influence a fly's survival from parasitoid attack: the size of the gall; the number of flies within a gall; and the fly's preference to create galls on particular genetic varieties of willow trees. Using these data they then created "fitness landscapes" using computer models, which visualize the adaptability of a species.
Fewer enemies, less variability
It turned out that different combinations of these three traits helped flies survive ? when all of the fly's natural enemies were present. "So there are several equally good solutions that ensure the survival of the fly," says Matt Barbour, the study's lead author. In contrast, after some natural enemies were removed, only one specific combination of traits helped flies survive. "This suggests that the extinction of natural enemies constrains fly evolution toward only one optimal solution." Genetic variations that lead to a different development of the traits could thus be permanently lost in the flies' genome.
This loss of diversity might be of consequence: "The diversity of potential solutions for survival acts to preserve genetic variability in the gall's traits," says Barbour. And since genetic variation provides the raw material for evolution, the findings suggest that the extinction of this fly's natural enemies may make it more difficult for it to adapt to a changing environment.
Read more at Science Daily
Why smartphones are digital truth serum
Researchers from University of Pennsylvania published a new paper in the Journal of Marketing that explains that the device people use to communicate can affect the extent to which they are willing to disclose intimate or personal information about themselves.
The study forthcoming in the Journal of Marketing is titled "Full Disclosure: How Smartphones Enhance Consumer Self-disclosure" and is authored by Shiri Melumad and Robert Meyer.
Do smartphones alter what people are willing to disclose about themselves to others? A new study in the Journal of Marketing suggests that they might. The research indicates that people are more willing to reveal personal information about themselves online using their smartphones compared to desktop computers. For example, Tweets and reviews composed on smartphones are more likely to be written from the perspective of the first person, to disclose negative emotions, and to discuss the writer's private family and personal friends. Likewise, when consumers receive an online ad that requests personal information (such as phone number and income), they are more likely to provide it when the request is received on their smartphone compared to their desktop or laptop computer.
Why do smartphones have this effect on behavior? Melumad explains that "Writing on one's smartphone often lowers the barriers to revealing certain types of sensitive information for two reasons; one stemming from the unique form characteristics of phones and the second from the emotional associations that consumers tend to hold with their device." First, one of the most distinguishing features of phones is the small size; something that makes viewing and creating content generally more difficult compared with desktop computers. Because of this difficulty, when writing or responding on a smartphone, a person tends to narrowly focus on completing the task and become less cognizant of external factors that would normally inhibit self-disclosure, such as concerns about what others would do with the information.?Smartphone users know this effect well -- when using their phones in public places, they often fixate so intently on its content that they become oblivious to what is going on around them.
The second reason people tend to be more self-disclosing on their phones lies in the feelings of comfort and familiarity people associate with their phones. Melumad adds, "Because our smartphones are with us all of the time and perform so many vital functions in our lives, they often serve as 'adult pacifiers' that bring feelings of comfort to their owners." The downstream effect of those feelings shows itself when people are more willing to disclose feelings to a close friend compared to a stranger or open up to a therapist in a comfortable rather than uncomfortable setting. As Meyer says, "Similarly, when writing on our phones, we tend to feel that we are in a comfortable 'safe zone.' As a consequence, we are more willing to open up about ourselves."
The data to support these ideas is far-ranging and includes analyses of thousands of social media posts and online reviews, responses to web ads, and controlled laboratory studies.?For example, initial evidence comes from analyses of the depth of self-disclosure?revealed in 369,161 Tweets and 10,185 restaurant reviews posted on TripAdvisor.com, with some posted on PCs and some on smartphones.? Using both automated natural-language processing tools and human judgements of self-disclosure, the researchers find robust evidence that smartphone-generated content is indeed more self-disclosing. Perhaps even more compelling is evidence from an analysis of 19,962 "call to action" web ads, where consumers are asked to provide private information.
Consistent with the tendency for smartphones to facilitate greater self-disclosure, compliance was systematically higher for ads targeted at smartphones versus PCs.
Read more at Science Daily
The study forthcoming in the Journal of Marketing is titled "Full Disclosure: How Smartphones Enhance Consumer Self-disclosure" and is authored by Shiri Melumad and Robert Meyer.
Do smartphones alter what people are willing to disclose about themselves to others? A new study in the Journal of Marketing suggests that they might. The research indicates that people are more willing to reveal personal information about themselves online using their smartphones compared to desktop computers. For example, Tweets and reviews composed on smartphones are more likely to be written from the perspective of the first person, to disclose negative emotions, and to discuss the writer's private family and personal friends. Likewise, when consumers receive an online ad that requests personal information (such as phone number and income), they are more likely to provide it when the request is received on their smartphone compared to their desktop or laptop computer.
Why do smartphones have this effect on behavior? Melumad explains that "Writing on one's smartphone often lowers the barriers to revealing certain types of sensitive information for two reasons; one stemming from the unique form characteristics of phones and the second from the emotional associations that consumers tend to hold with their device." First, one of the most distinguishing features of phones is the small size; something that makes viewing and creating content generally more difficult compared with desktop computers. Because of this difficulty, when writing or responding on a smartphone, a person tends to narrowly focus on completing the task and become less cognizant of external factors that would normally inhibit self-disclosure, such as concerns about what others would do with the information.?Smartphone users know this effect well -- when using their phones in public places, they often fixate so intently on its content that they become oblivious to what is going on around them.
The second reason people tend to be more self-disclosing on their phones lies in the feelings of comfort and familiarity people associate with their phones. Melumad adds, "Because our smartphones are with us all of the time and perform so many vital functions in our lives, they often serve as 'adult pacifiers' that bring feelings of comfort to their owners." The downstream effect of those feelings shows itself when people are more willing to disclose feelings to a close friend compared to a stranger or open up to a therapist in a comfortable rather than uncomfortable setting. As Meyer says, "Similarly, when writing on our phones, we tend to feel that we are in a comfortable 'safe zone.' As a consequence, we are more willing to open up about ourselves."
The data to support these ideas is far-ranging and includes analyses of thousands of social media posts and online reviews, responses to web ads, and controlled laboratory studies.?For example, initial evidence comes from analyses of the depth of self-disclosure?revealed in 369,161 Tweets and 10,185 restaurant reviews posted on TripAdvisor.com, with some posted on PCs and some on smartphones.? Using both automated natural-language processing tools and human judgements of self-disclosure, the researchers find robust evidence that smartphone-generated content is indeed more self-disclosing. Perhaps even more compelling is evidence from an analysis of 19,962 "call to action" web ads, where consumers are asked to provide private information.
Consistent with the tendency for smartphones to facilitate greater self-disclosure, compliance was systematically higher for ads targeted at smartphones versus PCs.
Read more at Science Daily
May 3, 2020
Scientists regenerate neurons in mice with spinal cord injury and optic nerve damage
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| Neuron illustration |
New research by scientists at the Lewis Katz School of Medicine Temple University (LKSOM) shows, however, that gains in functional recovery from these injuries may be possible, thanks to a molecule known as Lin28, which regulates cell growth. In a study published online in the journal Molecular Therapy, the Temple researchers describe the ability of Lin28 -- when expressed above its usual levels -- to fuel axon regrowth in mice with spinal cord injury or optic nerve injury, enabling repair of the body's communication grid.
"Our findings show that Lin28 is a major regulator of axon regeneration and a promising therapeutic target for central nervous system injuries," explained Shuxin Li, MD, PhD, Professor of Anatomy and Cell Biology and in the Shriners Hospitals Pediatric Research Center at the Lewis Katz School of Medicine at Temple University and senior investigator on the new study. The research is the first to demonstrate the regenerative ability of Lin28 upregulation in the injured spinal cord of animals.
"We became interested in Lin28 as a target for neuron regeneration because it acts as a gatekeeper of stem cell activity," said Dr. Li. "It controls the switch that maintains stem cells or allows them to differentiate and potentially contribute to activities such as axon regeneration."
To explore the effects of Lin28 on axon regrowth, Dr. Li and colleagues developed a mouse model in which animals expressed extra Lin28 in some of their tissues. When full-grown, the animals were divided into groups that sustained spinal cord injury or injury to the optic nerve tracts that connect to the retina in the eye.
Another set of adult mice, with normal Lin28 expression and similar injuries, were given injections of a viral vector (a type of carrier) for Lin28 to examine the molecule's direct effects on tissue repair.
Extra Lin28 stimulated long-distance axon regeneration in all instances, though the most dramatic effects were observed following post-injury injection of Lin28. In mice with spinal cord injury, Lin28 injection resulted in the growth of axons to more than three millimeters beyond the area of axon damage, while in animals with optic nerve injury, axons regrew the entire length of the optic nerve tract. Evaluation of walking and sensory abilities after Lin28 treatment revealed significant improvements in coordination and sensation.
"We observed a lot of axon regrowth, which could be very significant clinically, since there currently are no regenerative treatments for spinal cord injury or optic nerve injury," Dr. Li explained.
One of his goals in the near-term is to identify a safe and effective means of getting Lin28 to injured tissues in human patients. To do so, his team of researchers will need to develop a vector, or carrier system for Lin28, that can be injected systemically and then hone in on injured axons to deliver the therapy directly to multiple populations of damaged neurons.
Dr. Li further wants to decipher the molecular details of the Lin28 signaling pathway. "Lin28 associates closely with other growth signaling molecules, and we suspect it uses multiple pathways to regulate cell growth," he explained. These other molecules could potentially be packaged along with Lin28 to aid neuron repair.
Read more at Science Daily
Mind-controlled arm prostheses that 'feel' are now a part of everyday life
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| Touch definition |
The advance is unique: the patients have used a mind-controlled prosthesis in their everyday life for up to seven years. For the last few years, they have also lived with a new function -- sensations of touch in the prosthetic hand. This is a new concept for artificial limbs, which are called neuromusculoskeletal prostheses -- as they are connected to the user's nerves, muscles, and skeleton.
The research was led by Max Ortiz Catalan, Associate Professor at Chalmers University of Technology, in collaboration with Sahlgrenska University Hospital, University of Gothenburg, and Integrum AB, all in Gothenburg, Sweden. Researchers at Medical University of Vienna in Austria and the Massachusetts Institute of Technology in the USA were also involved.
"Our study shows that a prosthetic hand, attached to the bone and controlled by electrodes implanted in nerves and muscles, can operate much more precisely than conventional prosthetic hands. We further improved the use of the prosthesis by integrating tactile sensory feedback that the patients use to mediate how hard to grab or squeeze an object. Over time, the ability of the patients to discern smaller changes in the intensity of sensations has improved," says Max Ortiz Catalan.
"The most important contribution of this study was to demonstrate that this new type of prosthesis is a clinically viable replacement for a lost arm. No matter how sophisticated a neural interface becomes, it can only deliver real benefit to patients if the connection between the patient and the prosthesis is safe and reliable in the long term. Our results are the product of many years of work, and now we can finally present the first bionic arm prosthesis that can be reliably controlled using implanted electrodes, while also conveying sensations to the user in everyday life," continues Max Ortiz Catalan.
Since receiving their prostheses, the patients have used them daily in all their professional and personal activities.
The new concept of a neuromusculoskeletal prosthesis is unique in that it delivers several different features which have not been presented together in any other prosthetic technology in the world:
- It has a direct connection to a person's nerves, muscles, and skeleton.
- It is mind-controlled and delivers sensations that are perceived by the user as arising from the missing hand.
- It is self-contained; all electronics needed are contained within the prosthesis, so patients do not need to carry additional equipment or batteries.
- It is safe and stable in the long term; the technology has been used without interruption by patients during their everyday activities, without supervision from the researchers, and it is not restricted to confined or controlled environments.
The newest part of the technology, the sensation of touch, is possible through stimulation of the nerves that used to be connected to the biological hand before the amputation. Force sensors located in the thumb of the prosthesis measure contact and pressure applied to an object while grasping. This information is transmitted to the patients' nerves leading to their brains. Patients can thus feel when they are touching an object, its characteristics, and how hard they are pressing it, which is crucial for imitating a biological hand.
"Currently, the sensors are not the obstacle for restoring sensation," says Max Ortiz Catalan. "The challenge is creating neural interfaces that can seamlessly transmit large amounts of artificially collected information to the nervous system, in a way that the user can experience sensations naturally and effortlessly."
The implantation of this new technology took place at Sahlgrenska University Hospital, led by Professor Rickard Brånemark and Doctor Paolo Sassu. Over a million people worldwide suffer from limb loss, and the end goal for the research team, in collaboration with Integrum AB, is to develop a widely available product suitable for as many of these people as possible.
"Right now, patients in Sweden are participating in the clinical validation of this new prosthetic technology for arm amputation," says Max Ortiz Catalan. "We expect this system to become available outside Sweden within a couple of years, and we are also making considerable progress with a similar technology for leg prostheses, which we plan to implant in a first patient later this year."
More about: How the technology works
The implant system for the arm prosthesis is called e-OPRA and is based on the OPRA implant system created by Integrum AB. The implant system anchors the prosthesis to the skeleton in the stump of the amputated limb, through a process called osseointegration (osseo = bone). Electrodes are implanted in muscles and nerves inside the amputation stump, and the e-OPRA system sends signals in both directions between the prosthesis and the brain, just like in a biological arm.
The prosthesis is mind-controlled, via the electrical muscle and nerve signals sent through the arm stump and captured by the electrodes. The signals are passed into the implant, which goes through the skin and connects to the prosthesis. The signals are then interpreted by an embedded control system developed by the researchers. The control system is small enough to fit inside the prosthesis and it processes the signals using sophisticated artificial intelligence algorithms, resulting in control signals for the prosthetic hand's movements.
The touch sensations arise from force sensors in the prosthetic thumb. The signals from the sensors are converted by the control system in the prosthesis into electrical signals which are sent to stimulate a nerve in the arm stump. The nerve leads to the brain, which then perceives the pressure levels against the hand.
The neuromusculoskeletal implant can connect to any commercially available arm prosthesis, allowing them to operate more effectively.
More about: How the artificial sensation is experienced
People who lose an arm or leg often experience phantom sensations, as if the missing body part remains although not physically present. When the force sensors in the prosthetic thumb react, the patients in the study feel that the sensation comes from their phantom hand. Precisely where on the phantom hand varies between patients, depending on which nerves in the stump receive the signals. The lowest level of pressure can be compared to touching the skin with the tip of a pencil. As the pressure increases, the feeling becomes stronger and increasingly 'electric'.
More about: The research
The current study dealt with patients with above-elbow amputations, and this technology is close to becoming a finished product. The research team is working in parallel with a new system for amputations below the elbow. In those cases, instead of one large bone (humerus), there are two smaller bones (radius and ulna) to which the implant needs to be anchored. The group is also working on adapting the system for leg prostheses.
In addition to applications within prosthetics, the permanent interface between human and machine provides entirely new opportunities for scientific research into how the human muscular and nervous systems work.
Read more at Science Daily
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