A team of University of Illinois researchers estimated the mortality costs associated with air pollution in the U.S. by developing and applying a novel machine learning-based method to estimate the life-years lost and cost associated with air pollution exposure.
Scholars from the Gies College of Business at Illinois studied the causal effects of acute fine particulate matter exposure on mortality, health care use and medical costs among older Americans through Medicare data and a unique way of measuring air pollution via changes in local wind direction.
The researchers -- Tatyana Deryugina, Nolan Miller, David Molitor and Julian Reif -- calculated that the reduction in particulate matter experienced between 1999-2013 resulted in elderly mortality reductions worth $24 billion annually by the end of that period. Garth Heutel of Georgia State University and the National Bureau of Economic Research was a co-author of the paper.
"Our goal with this paper was to quantify the costs of air pollution on mortality in a particularly vulnerable population: the elderly," said Deryugina, a professor of finance who studies the health effects and distributional impact of air pollution. "Understanding how air pollution affects mortality, health care use and medical costs is essential for crafting efficient environment policies because outside factors such as a person's preexisting health conditions can make it challenging to accurately estimate the causal effects of pollution on health."
About 25% of the elderly Medicare population was vulnerable to acute pollution shocks, according to the researchers.
"Our analysis shows that the most vulnerable Medicare beneficiaries are those who suffer from chronic conditions and have high health care spending," said Reif, a professor of finance and a faculty member of the Institute of Government and Public Affairs. "We estimate that members of the most vulnerable group -- those with a life expectancy of less than one year -- are over 30 times more likely to die from pollution than the typical Medicare beneficiary."
"Because we take a big data approach, we're able to see how air pollution affects the entire elderly population of the U.S. over those 14 years," said Miller, the Daniel and Cynthia Mah Helle Professor of Finance. "Medicare data is great because it has every interaction with the health care system in our sample for virtually every elderly person."
The typical air pollution research is more of a case study, Miller said.
"There's a pollution event in a certain city, and there's a mortality count around this event, but it's hard to get an accurate general estimate of the overall impact," he said. "Pollution is produced as a package: You burn stuff and it produces particulate matter, but it also produces other pollutants. Our methodology is able to take a lot of data, people and pollution events into account. And that allows us to more accurately identify the overall impact of pollution, because wind patterns affect these different pollutants in different ways. So we can tease apart which of these pollutants we think is most important and driving these mortality effects."
By exploiting the daily variation in acute fine particulate pollution exposure driven by changes in wind direction, the researchers found significant effects of exposure on mortality, hospitalizations and medical spending.
"A key part of the study was harnessing 40 billion observations with machine learning techniques," said Molitor, a professor of finance. "We used machine learning to predict how long people would have lived in the absence of the pollution event and to illuminate who is most vulnerable to pollution. One takeaway is that an individual's life expectancy -- how much longer they can expect to live -- is a much better measure of vulnerability to pollution than their age."
The scholars also found that increases in particulate matter lead to more emergency room visits, hospitalizations and higher patient spending.
"Mortality is only one of many potential costs of air pollution," Molitor said. "The elderly who aren't dying may engage in other costly activities such as going to the hospital for preventive or emergency care. Those steps may help them avoid death, but it doesn't mean that pollution has no cost to their health or finances."
Notably, the researchers also found that the failure to adjust for the preexisting health of those who die from an acute pollution event tends to overstate the mortality-reduction benefits of decreasing air pollution.
"An issue that arises when estimating mortality effects is whether those who die from pollution exposure would have passed away soon anyway without that external pollution shock," Molitor said. "If deaths caused by pollution occur disproportionately among the least healthy, then ignoring this factor could lead to an overstatement of the life years lost due to pollution."
"But we found that the typical person who dies as a result of pollution exposure isn't someone you would expect to die in a week or a month," Miller said. "It's people who have 3.6 years on average to live, compared with about 11 years for the typical elderly Medicare enrollee. So, although they are less healthy than the average Medicare recipient, these are people who we expect to have three and a half reasonably healthy years of life, and this should definitely not be ignored."
Read more at Science Daily
Jan 26, 2020
Many youth living with undiagnosed chronic fatigue syndrome
Most youth living with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have not been diagnosed, according to a new prevalence study from researchers at DePaul University and Ann & Robert H. Lurie Children's Hospital of Chicago, published by the journal Child & Youth Care Forum. Leonard A. Jason, a professor of psychology at DePaul University, led the seven-year study to screen more than 10,000 children and teenagers in the Chicago area.
The researchers found that less than 5% of youth in the study who tested positive for ME/CFS had been previously diagnosed with the illness. Of the children assessed, African American and Latinx youth were twice as likely to be living with undiagnosed ME/CFS. The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, one of the National Institutes of Health. Jason has been studying ME/CFS for more than 30 years and says the illness can affect all aspects of a child's life, from physical functioning to attending school and participating in extracurricular activities.
"When you're talking about a condition that's as debilitating as this one, the health care response has not been good," said Jason. "There aren't that many physicians who are trained and skilled at diagnosing and treating this illness, and our health care system has not done a great job at trying to help people who are affected," said Jason, director of DePaul's Center for Community Research.
Working with Jason as co-principal investigator is Dr. Ben Z. Katz, a pediatric infectious disease specialist at the Ann & Robert H. Lurie Children's Hospital of Chicago. Katz is also a professor of pediatrics at Northwestern University Feinberg School of Medicine. He has collaborated with Jason and his group since the late 1990s.
"Our finding that most youth with ME/CFS have not been previously diagnosed is comparable to findings in adults," said Katz. "We definitely need better ways to identify people with this illness and to develop effective interventions for them. In particular, we need to reach African American and Hispanic youth, since in our study these groups had higher prevalence of ME/CFS. "
The prevalence of pediatric ME/CFS has been in dispute, so Jason and Katz set out to include a diverse sample of ethnic, socio-economic and demographic backgrounds. Other ME/CFS prevalence studies have drawn from tertiary care centers, which can exclude those without access to health care, explained Jason. The researchers tailored their approach by including a thorough medical and psychiatric examination, offering access to high-quality screening for those at-risk of having the illness.
Researchers screened a random sample of 10,119 youth ages 5-17 from 5,622 households. The first stage was a phone interview with parents and caretakers about the health and behavior of their children and teens. Missing school because of fatigue was one of the common symptoms among youth who showed a higher risk of having ME/CFS, and was a red flag for parents, said Jason.
Of those who screened positive over the phone, 165 youth went on to medical and psychiatric examinations. Following evaluations, a team of physicians made final diagnoses. Youth were given a diagnosis of ME/CFS if they met criteria for case definitions. Of the 42 youth diagnosed with ME/CFS, only 2 (4.8%) had been previously diagnosed with the illness.
Prevalence of pediatric ME/CFS was 0.75%, which is a bit less than 1%, with a higher prevalence among African American and Latinx youth compared to their Caucasian peers. "Clearly people of color do get this illness, and there are some myths that you have to be white middle class to have ME/CFS," said Jason.
A lack of access to health care, and therefore less opportunity for an earlier diagnosis, could explain this racial disparity, according to Jason. "There are barriers to researchers gaining access to underserved populations. They may not trust institutions as easily, and they may not also have time to bring their children into appointments," said Jason.
And, there is still stigma and misunderstanding about ME/CFS among health care providers. "They may not believe this is a condition, or might attribute it to fatigue," said Jason.
Read more at Science Dialy
The researchers found that less than 5% of youth in the study who tested positive for ME/CFS had been previously diagnosed with the illness. Of the children assessed, African American and Latinx youth were twice as likely to be living with undiagnosed ME/CFS. The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, one of the National Institutes of Health. Jason has been studying ME/CFS for more than 30 years and says the illness can affect all aspects of a child's life, from physical functioning to attending school and participating in extracurricular activities.
"When you're talking about a condition that's as debilitating as this one, the health care response has not been good," said Jason. "There aren't that many physicians who are trained and skilled at diagnosing and treating this illness, and our health care system has not done a great job at trying to help people who are affected," said Jason, director of DePaul's Center for Community Research.
Working with Jason as co-principal investigator is Dr. Ben Z. Katz, a pediatric infectious disease specialist at the Ann & Robert H. Lurie Children's Hospital of Chicago. Katz is also a professor of pediatrics at Northwestern University Feinberg School of Medicine. He has collaborated with Jason and his group since the late 1990s.
"Our finding that most youth with ME/CFS have not been previously diagnosed is comparable to findings in adults," said Katz. "We definitely need better ways to identify people with this illness and to develop effective interventions for them. In particular, we need to reach African American and Hispanic youth, since in our study these groups had higher prevalence of ME/CFS. "
The prevalence of pediatric ME/CFS has been in dispute, so Jason and Katz set out to include a diverse sample of ethnic, socio-economic and demographic backgrounds. Other ME/CFS prevalence studies have drawn from tertiary care centers, which can exclude those without access to health care, explained Jason. The researchers tailored their approach by including a thorough medical and psychiatric examination, offering access to high-quality screening for those at-risk of having the illness.
Researchers screened a random sample of 10,119 youth ages 5-17 from 5,622 households. The first stage was a phone interview with parents and caretakers about the health and behavior of their children and teens. Missing school because of fatigue was one of the common symptoms among youth who showed a higher risk of having ME/CFS, and was a red flag for parents, said Jason.
Of those who screened positive over the phone, 165 youth went on to medical and psychiatric examinations. Following evaluations, a team of physicians made final diagnoses. Youth were given a diagnosis of ME/CFS if they met criteria for case definitions. Of the 42 youth diagnosed with ME/CFS, only 2 (4.8%) had been previously diagnosed with the illness.
Prevalence of pediatric ME/CFS was 0.75%, which is a bit less than 1%, with a higher prevalence among African American and Latinx youth compared to their Caucasian peers. "Clearly people of color do get this illness, and there are some myths that you have to be white middle class to have ME/CFS," said Jason.
A lack of access to health care, and therefore less opportunity for an earlier diagnosis, could explain this racial disparity, according to Jason. "There are barriers to researchers gaining access to underserved populations. They may not trust institutions as easily, and they may not also have time to bring their children into appointments," said Jason.
And, there is still stigma and misunderstanding about ME/CFS among health care providers. "They may not believe this is a condition, or might attribute it to fatigue," said Jason.
Read more at Science Dialy
Jan 25, 2020
How human social structures emerge
What rules shaped humanity's original social networks? Researchers in Japan developed new mathematical models to understand what conditions produced traditional community structures and conventions around the world, including taboos about incest.
"We think this is the first time cultural anthropology and computer simulations have met in a single research study," said Professor Kunihiko Kaneko, an expert in theoretical biology and physics from the University of Tokyo Research Center for Complex Systems Biology.
Researchers used statistical physics and computer models common in evolutionary biology to explain the origin of common community structures documented by cultural anthropologists around the world.
The earliest social networks were tightly knit cultural groups made of multiple biologically related families. That single group would then develop relationships with other cultural groups in their local area.
In the 1960s, cultural anthropologists documented social networks of indigenous communities and identified two kinship structures common around the world. In areas with hunter-gatherer communities, anthropologists documented direct-exchange kinship structures where women from two communities change places when they marry. In areas with agrarian farming communities, kinship structures of generalized exchange developed where women move between multiple communities to marry.
"Anthropologists have documented kinship structures all over the world, but it still remains unclear how those structures emerged and why they have common properties," said Kenji Itao, a first year master's degree student in Kaneko's laboratory, whose interdisciplinary interests in physics, math and anthropology motivated this research study.
Experts in anthropology consider the incest taboo to be an extremely common social rule affecting kinship structures. The ancient incest taboo focused on social closeness, rather than genetic or blood relationships, meaning it was taboo to marry anyone born into the same cultural group.
Itao and Kaneko designed a mathematical model and computer simulation to test what external factors might cause generations of biologically related families to organize into communities with incest taboos and direct or generalized exchange of brides.
"Traditionally, it is more common for women to move to a new community when they marry, but we did not include any gender differences in this computer simulation," explained Itao.
Simulated family groups with shared traits and desires naturally grouped together into distinct cultural groups. However, the traits the group possessed were different from the traits they desired in marriage partners, meaning they did not desire spouses similar to themselves. This is the underlying cause of the traditional community-based incest taboo suggested by the study.
When the computer simulation pushed communities to cooperate, generalized exchange kinship structures arose. The simulation demonstrated different kinship structures, including the direct exchange basic structure, emerge depending on the strength of conflict to find brides and the necessity of cooperation with specific other communities.
"It is rewarding to see that the combination of statistical physics and evolution theory, together with computer simulations, will be relevant to identify universal properties that affect human societies," said Kaneko.
The current computer model is simple and only included factors of conflict and cooperation affecting marriage, but researchers hope to continue developing the model to also consider economic factors that might cause communities to separate into different classes. With these additions, the theory can hopefully be extended to explore different communities in the modern, global society.
Read more at Science Daily
"We think this is the first time cultural anthropology and computer simulations have met in a single research study," said Professor Kunihiko Kaneko, an expert in theoretical biology and physics from the University of Tokyo Research Center for Complex Systems Biology.
Researchers used statistical physics and computer models common in evolutionary biology to explain the origin of common community structures documented by cultural anthropologists around the world.
The earliest social networks were tightly knit cultural groups made of multiple biologically related families. That single group would then develop relationships with other cultural groups in their local area.
In the 1960s, cultural anthropologists documented social networks of indigenous communities and identified two kinship structures common around the world. In areas with hunter-gatherer communities, anthropologists documented direct-exchange kinship structures where women from two communities change places when they marry. In areas with agrarian farming communities, kinship structures of generalized exchange developed where women move between multiple communities to marry.
"Anthropologists have documented kinship structures all over the world, but it still remains unclear how those structures emerged and why they have common properties," said Kenji Itao, a first year master's degree student in Kaneko's laboratory, whose interdisciplinary interests in physics, math and anthropology motivated this research study.
Experts in anthropology consider the incest taboo to be an extremely common social rule affecting kinship structures. The ancient incest taboo focused on social closeness, rather than genetic or blood relationships, meaning it was taboo to marry anyone born into the same cultural group.
Itao and Kaneko designed a mathematical model and computer simulation to test what external factors might cause generations of biologically related families to organize into communities with incest taboos and direct or generalized exchange of brides.
"Traditionally, it is more common for women to move to a new community when they marry, but we did not include any gender differences in this computer simulation," explained Itao.
Simulated family groups with shared traits and desires naturally grouped together into distinct cultural groups. However, the traits the group possessed were different from the traits they desired in marriage partners, meaning they did not desire spouses similar to themselves. This is the underlying cause of the traditional community-based incest taboo suggested by the study.
When the computer simulation pushed communities to cooperate, generalized exchange kinship structures arose. The simulation demonstrated different kinship structures, including the direct exchange basic structure, emerge depending on the strength of conflict to find brides and the necessity of cooperation with specific other communities.
"It is rewarding to see that the combination of statistical physics and evolution theory, together with computer simulations, will be relevant to identify universal properties that affect human societies," said Kaneko.
The current computer model is simple and only included factors of conflict and cooperation affecting marriage, but researchers hope to continue developing the model to also consider economic factors that might cause communities to separate into different classes. With these additions, the theory can hopefully be extended to explore different communities in the modern, global society.
Read more at Science Daily
Traces of the European enlightenment found in the DNA of western sign languages
Sign languages throughout North and South America and Europe have centuries-long roots in five European locations, a finding that gives new insight into the influence of the European Enlightenment on many of the world's signing communities and the evolution of their languages.
Linguists and biologists from The University of Texas at Austin and the Max Planck Institute for the Science of Human History adapted techniques from genetic research to study the origins of Western sign languages, identifying five European lineages -- Austrian, British, French, Spanish and Swedish -- that began spreading to other parts of the world in the late 18th century. The study, published in Royal Society Open Science, highlights the establishment and growth of European deaf communities during an age of widespread enlightenment and their impact on sign languages used today.
"While the evolution of spoken languages has been studied for more than 200 years, research on sign language evolution is still in its infancy," said Justin Power, a doctoral candidate in linguistics at UT Austin and the study's first author, noting that most research has been based on historical records from deaf educators and institutions. "But there is no a priori reason that one should only study spoken languages if one wants to better understand human language evolution in general."
Much like a geneticist would look to DNA to study traits passed down through generations, the study's researchers investigated data from dozens of Western sign languages, in particular, the manual alphabets, or sets of handshapes signers use to spell written words. As certain handshape forms were passed on within a lineage, they became characteristic of the lineage itself and could be used as markers to identify it.
To identify such markers and decipher the origins of each language, the researchers built the largest cross-linguistic comparative database to map the complex evolutionary relationships among 40 contemporary and 36 historical manual alphabets.
"In both biological and linguistic evolution, traits are passed on from generation to generation. But the types of traits that are passed on and the ways in which they are passed on differ. So, we might expect many differences in the ways that humans and their languages evolve," Power said. "This database allowed us to analyze a variety of reasons for commonalities between languages, such as inheriting from a common ancestral language, borrowing from an unrelated language, or developing similar forms independently."
The researchers grouped the sign languages into five main evolutionary lineages, which developed independently of one another between the mid-18th to early 19th centuries. They were also interested to find that three of the main continental lineages -- Austrian, French and Spanish -- all appeared to have been influenced by early Spanish manual alphabets, which represented the 22 letters of Latin.
"It's likely that the early Spanish manual alphabets were used in limited ways by clergy or itinerant teachers of the deaf, but later signing communities added new handshapes to represent letters in the alphabets of their written languages," Power said. "When large-scale schools for the deaf were established, the manual alphabets came into use in signing communities by relatively large groups of people. It is at this point where we put the beginnings of most of these five lineages."
Data from the languages themselves confirmed many of the sign language dispersal events known from historical records, such as the influence of French Sign Language on deaf education and signing communities in many countries, including in Western Europe and the Americas. However, the researchers were surprised to trace the dispersal of Austrian Sign Language to central and northern Europe, as well as to Russia -- a lineage about which little was previously known.
Read more at Science Daily
Linguists and biologists from The University of Texas at Austin and the Max Planck Institute for the Science of Human History adapted techniques from genetic research to study the origins of Western sign languages, identifying five European lineages -- Austrian, British, French, Spanish and Swedish -- that began spreading to other parts of the world in the late 18th century. The study, published in Royal Society Open Science, highlights the establishment and growth of European deaf communities during an age of widespread enlightenment and their impact on sign languages used today.
"While the evolution of spoken languages has been studied for more than 200 years, research on sign language evolution is still in its infancy," said Justin Power, a doctoral candidate in linguistics at UT Austin and the study's first author, noting that most research has been based on historical records from deaf educators and institutions. "But there is no a priori reason that one should only study spoken languages if one wants to better understand human language evolution in general."
Much like a geneticist would look to DNA to study traits passed down through generations, the study's researchers investigated data from dozens of Western sign languages, in particular, the manual alphabets, or sets of handshapes signers use to spell written words. As certain handshape forms were passed on within a lineage, they became characteristic of the lineage itself and could be used as markers to identify it.
To identify such markers and decipher the origins of each language, the researchers built the largest cross-linguistic comparative database to map the complex evolutionary relationships among 40 contemporary and 36 historical manual alphabets.
"In both biological and linguistic evolution, traits are passed on from generation to generation. But the types of traits that are passed on and the ways in which they are passed on differ. So, we might expect many differences in the ways that humans and their languages evolve," Power said. "This database allowed us to analyze a variety of reasons for commonalities between languages, such as inheriting from a common ancestral language, borrowing from an unrelated language, or developing similar forms independently."
The researchers grouped the sign languages into five main evolutionary lineages, which developed independently of one another between the mid-18th to early 19th centuries. They were also interested to find that three of the main continental lineages -- Austrian, French and Spanish -- all appeared to have been influenced by early Spanish manual alphabets, which represented the 22 letters of Latin.
"It's likely that the early Spanish manual alphabets were used in limited ways by clergy or itinerant teachers of the deaf, but later signing communities added new handshapes to represent letters in the alphabets of their written languages," Power said. "When large-scale schools for the deaf were established, the manual alphabets came into use in signing communities by relatively large groups of people. It is at this point where we put the beginnings of most of these five lineages."
Data from the languages themselves confirmed many of the sign language dispersal events known from historical records, such as the influence of French Sign Language on deaf education and signing communities in many countries, including in Western Europe and the Americas. However, the researchers were surprised to trace the dispersal of Austrian Sign Language to central and northern Europe, as well as to Russia -- a lineage about which little was previously known.
Read more at Science Daily
Jan 24, 2020
Will the future's super batteries be made of seawater?
We all know the rechargeable and efficient lithium ion (Li-ion) batteries sitting in our smartphones, laptops and also in electric cars.
Unfortunately, lithium is a limited resource, so it will be a challenge to satisfy the worlds' growing demand for relatively cheap batteries. Therefore, researchers are now looking for alternatives to the Li-ion battery.
A promising alternative is to replace lithium with the metal sodium -- to make Na-ion batteries. Sodium is found in large quantities in seawater and can be easily extracted from it.
"The Na-ion battery is still under development, and researchers are working on increasing its service life, lowering its charging time and making batteries that can deliver many watts," says research leader Dorthe Bomholdt Ravnsbæk of the Department of Physics, Chemistry and Pharmacy at University of Southern Denmark.
She and her team are preoccupied with developing new and better rechargeable batteries that can replace todays' widely used Li-ion batteries.
For the Na-ion batteries to become an alternative, better electrode materials must be developed -- something she and colleagues from the University of Technology and the Massachusetts Institute of Technology, USA, have looked at in a new study published in the journal ACS Applied Energy Materials.
But before looking at the details of this study, let's take a look at why the Na-ion battery has the potential to become the next big battery success.
"An obvious advantage is that sodium is a very readily available resource, which is found in very large quantities in seawater. Lithium, on the other hand, is a limited resource that is mined only in a few places in the world," explains Dorthe Bomholdt Ravnsbæk.
Another advantage is that Na-ion batteries do not need cobalt, which is still needed in Li-ion batteries. The majority of the cobalt used today to make Li-ion batteries, is mined in the Democratic Republic of Congo, where rebellion, disorganized mining and child labor create uncertainty and moral qualms regarding the country's cobalt trade.
It also counts on the plus side that Na-ion batteries can be produced at the same factories that make Li-ion batteries today.
In their new study, Dorthe Bomholdt Ravnsbæk and her colleagues have investigated a new electrode material based on iron, manganese and phosphorus.
The new thing about the material is the addition of the element manganese, which not only gives the battery a higher voltage (volts), but also increases the capacity of the battery and is likely to deliver more watts. This is because the transformations that occur at the atomic level during the discharge and charge are significantly changed by the presence of manganese.
"Similar effects have been seen in Li-ion batteries, but it is very surprising that the effect is retained in a Na-ion battery, since the interaction between the electrode and Na-ions is very different from that of Li-ions," says Dorthe Bomholdt Ravnsbæk.
She will not try and predict when we can expect to find seawater-based Na-ion batteries in our phones and electric cars, because there are still some challenges to be solved.
One challenge is that it can be difficult to make small Na-ion batteries. But large batteries also have value -- for example, when it comes to storing wind or solar energy.
Read more at Science Daily
Unfortunately, lithium is a limited resource, so it will be a challenge to satisfy the worlds' growing demand for relatively cheap batteries. Therefore, researchers are now looking for alternatives to the Li-ion battery.
A promising alternative is to replace lithium with the metal sodium -- to make Na-ion batteries. Sodium is found in large quantities in seawater and can be easily extracted from it.
"The Na-ion battery is still under development, and researchers are working on increasing its service life, lowering its charging time and making batteries that can deliver many watts," says research leader Dorthe Bomholdt Ravnsbæk of the Department of Physics, Chemistry and Pharmacy at University of Southern Denmark.
She and her team are preoccupied with developing new and better rechargeable batteries that can replace todays' widely used Li-ion batteries.
For the Na-ion batteries to become an alternative, better electrode materials must be developed -- something she and colleagues from the University of Technology and the Massachusetts Institute of Technology, USA, have looked at in a new study published in the journal ACS Applied Energy Materials.
But before looking at the details of this study, let's take a look at why the Na-ion battery has the potential to become the next big battery success.
"An obvious advantage is that sodium is a very readily available resource, which is found in very large quantities in seawater. Lithium, on the other hand, is a limited resource that is mined only in a few places in the world," explains Dorthe Bomholdt Ravnsbæk.
Another advantage is that Na-ion batteries do not need cobalt, which is still needed in Li-ion batteries. The majority of the cobalt used today to make Li-ion batteries, is mined in the Democratic Republic of Congo, where rebellion, disorganized mining and child labor create uncertainty and moral qualms regarding the country's cobalt trade.
It also counts on the plus side that Na-ion batteries can be produced at the same factories that make Li-ion batteries today.
In their new study, Dorthe Bomholdt Ravnsbæk and her colleagues have investigated a new electrode material based on iron, manganese and phosphorus.
The new thing about the material is the addition of the element manganese, which not only gives the battery a higher voltage (volts), but also increases the capacity of the battery and is likely to deliver more watts. This is because the transformations that occur at the atomic level during the discharge and charge are significantly changed by the presence of manganese.
"Similar effects have been seen in Li-ion batteries, but it is very surprising that the effect is retained in a Na-ion battery, since the interaction between the electrode and Na-ions is very different from that of Li-ions," says Dorthe Bomholdt Ravnsbæk.
She will not try and predict when we can expect to find seawater-based Na-ion batteries in our phones and electric cars, because there are still some challenges to be solved.
One challenge is that it can be difficult to make small Na-ion batteries. But large batteries also have value -- for example, when it comes to storing wind or solar energy.
Read more at Science Daily
The color of your clothing can impact wildlife
Your choice of clothing could affect the behavioral habits of wildlife around you, according to a study conducted by a team of researchers, including faculty at Binghamton University, State University of New York.
Lindsey Swierk, assistant research professor of biological sciences at Binghamton University, collaborated on a study with the goal of seeing how ecotourists could unintentionally have an effect on wildlife native to the area. Swierk and her team went to Costa Rica to conduct this study on water anoles (Anolis aquaticus), a variety of the anole lizard.
"I've studied water anoles for five years now, and I still find myself surprised by their unique natural history and behavior," Swierk said. "One reason water anoles were chosen is because they are restricted to a fairly small range and we could be pretty sure that these particular populations hadn't seen many humans in their lifetimes. So we had a lot of confidence that these populations were not biased by previous human interactions."
The researchers went to the Las Cruces Biological Center in Costa Rica. To collect data, they visited three different river locations wearing one of three different colored shirts: orange, green or blue. The study's focus was to see how these water anoles reacted to the different colors. Orange was chosen because the water anole has orange sexual signals. Blue was chosen as a contrast, as the water anole's body lacks the color blue. Green was selected as a similar color to the tropical forest environment of the testing site.
"Based on previous work on how animals respond to color stimuli, we developed a hypothesis that wearing colors that are 'worn' by water anoles themselves would be less frightening to these lizards," Swierk said.
The results of the study supported that hypothesis, with researchers with orange shirts reporting more anoles seen per hour and a higher anole capture percentage. Despite predicting the result, Swierk said that she was surprised by some of the findings. "It was still very surprising to see that the color green, which camouflaged us well in the forest, was less effective than wearing a very bright orange!"
Swierk said that one of the biggest takeaways from this study is that we may not yet quite understand how animals view the world.
"We (both researchers and ecotourists) need to recognize that animals perceive the world differently than we do as humans," said Swierk. "They have their own 'lenses' based on their unique evolutionary histories. What we imagine is frightening for an animal might not be; conversely, what we imagine is non-threatening could be terrifying in reality."
Swierk hopes that these results may be used within the ecotourism community to reduce impacts on the wildlife that they wish to view.
She said that more research needs to be done before this study can be related to other animals with less-sophisticated abilities of color perception, such as mammals.
Read more at Science Daily
Lindsey Swierk, assistant research professor of biological sciences at Binghamton University, collaborated on a study with the goal of seeing how ecotourists could unintentionally have an effect on wildlife native to the area. Swierk and her team went to Costa Rica to conduct this study on water anoles (Anolis aquaticus), a variety of the anole lizard.
"I've studied water anoles for five years now, and I still find myself surprised by their unique natural history and behavior," Swierk said. "One reason water anoles were chosen is because they are restricted to a fairly small range and we could be pretty sure that these particular populations hadn't seen many humans in their lifetimes. So we had a lot of confidence that these populations were not biased by previous human interactions."
The researchers went to the Las Cruces Biological Center in Costa Rica. To collect data, they visited three different river locations wearing one of three different colored shirts: orange, green or blue. The study's focus was to see how these water anoles reacted to the different colors. Orange was chosen because the water anole has orange sexual signals. Blue was chosen as a contrast, as the water anole's body lacks the color blue. Green was selected as a similar color to the tropical forest environment of the testing site.
"Based on previous work on how animals respond to color stimuli, we developed a hypothesis that wearing colors that are 'worn' by water anoles themselves would be less frightening to these lizards," Swierk said.
The results of the study supported that hypothesis, with researchers with orange shirts reporting more anoles seen per hour and a higher anole capture percentage. Despite predicting the result, Swierk said that she was surprised by some of the findings. "It was still very surprising to see that the color green, which camouflaged us well in the forest, was less effective than wearing a very bright orange!"
Swierk said that one of the biggest takeaways from this study is that we may not yet quite understand how animals view the world.
"We (both researchers and ecotourists) need to recognize that animals perceive the world differently than we do as humans," said Swierk. "They have their own 'lenses' based on their unique evolutionary histories. What we imagine is frightening for an animal might not be; conversely, what we imagine is non-threatening could be terrifying in reality."
Swierk hopes that these results may be used within the ecotourism community to reduce impacts on the wildlife that they wish to view.
She said that more research needs to be done before this study can be related to other animals with less-sophisticated abilities of color perception, such as mammals.
Read more at Science Daily
US households waste nearly a third of the food they acquire
American households waste, on average, almost a third of the food they acquire, according to economists, who say this wasted food has an estimated aggregate value of $240 billion annually. Divided among the nearly 128.6 million U.S. households, this waste could be costing the average household about $1,866 per year.
This inefficiency in the food economy has implications for health, food security, food marketing and climate change, noted Edward Jaenicke, professor of agricultural economics, College of Agricultural Sciences, Penn State.
"Our findings are consistent with previous studies, which have shown that 30% to 40% of the total food supply in the United States goes uneaten -- and that means that resources used to produce the uneaten food, including land, energy, water and labor, are wasted as well," Jaenicke said. "But this study is the first to identify and analyze the level of food waste for individual households, which has been nearly impossible to estimate because comprehensive, current data on uneaten food at the household level do not exist."
The researchers overcame this limitation by borrowing methodology from the fields of production economics -- which models the production function of transforming inputs into outputs -- and nutritional science, by which a person's height, weight, gender and age can be used to calculate metabolic energy requirements to maintain body weight.
In this novel approach, Jaenicke and Yang Yu, doctoral candidate in agricultural, environmental and regional economics, analyzed data primarily from 4,000 households that participated in the U.S. Department of Agriculture's National Household Food Acquisition and Purchase Survey, known as FoodAPS. Food-acquisition data from this survey were treated as the "input."
FoodAPS also collected biological measures of participants, enabling the researchers to apply formulas from nutritional science to determine basal metabolic rates and calculate the energy required for household members to maintain body weight, which is the "output." The difference between the amount of food acquired and the amount needed to maintain body weight represents the production inefficiency in the model, which translates to uneaten, and therefore wasted, food.
"Based on our estimation, the average American household wastes 31.9% of the food it acquires," Jaenicke said. "More than two-thirds of households in our study have food-waste estimates of between 20% and 50%. However, even the least wasteful household wastes 8.7% of the food it acquires."
In addition, demographic data collected as part of the survey were used to analyze the differences in food waste among households with a variety of characteristics.
For example, households with higher income generate more waste, and those with healthier diets that include more perishable fruits and vegetables also waste more food, according to the researchers, who reported their findings in the American Journal of Agricultural Economics.
"It's possible that programs encouraging healthy diets may unintentionally lead to more waste," Jaenicke said. "That may be something to think about from a policy perspective -- how can we fine-tune these programs to reduce potential waste."
Household types associated with less food waste include those with greater food insecurity -- especially those that participate in the federal SNAP food assistance program, previously known as "food stamps" -- as well as those households with a larger number of members.
"People in larger households have more meal-management options," Jaenicke explained. "More people means leftover food is more likely to be eaten."
In addition, some grocery items are sold in sizes that may influence waste, he said.
"A household of two may not eat an entire head of cauliflower, so some could be wasted, whereas a larger household is more likely to eat all of it, perhaps at a single meal."
Among other households with lower levels of waste are those who use a shopping list when visiting the supermarket and those who must travel farther to reach their primary grocery store.
"This suggests that planning and food management are factors that influence the amount of wasted food," Jaenicke said.
Beyond the economic and nutritional implications, reducing food waste could be a factor in minimizing the effects of climate change. Previous studies have shown that throughout its life cycle, discarded food is a major source of greenhouse gas emissions, the researchers pointed out.
"According to the U.N. Food and Agriculture Organization, food waste is responsible for about 3.3 gigatons of greenhouse gas annually, which would be, if regarded as a country, the third-largest emitter of carbon after the U.S. and China," Jaenicke said.
The researchers suggested that this study can help fill the need for comprehensive food-waste estimates at the household level that can be generalized to a wide range of household groups.
"While the precise measurement of food waste is important, it may be equally important to investigate further how household-specific factors influence how much food is wasted," said Jaenicke. "We hope our methodology provides a new lens through which to analyze individual household food waste."
Read more at Science Daily
This inefficiency in the food economy has implications for health, food security, food marketing and climate change, noted Edward Jaenicke, professor of agricultural economics, College of Agricultural Sciences, Penn State.
"Our findings are consistent with previous studies, which have shown that 30% to 40% of the total food supply in the United States goes uneaten -- and that means that resources used to produce the uneaten food, including land, energy, water and labor, are wasted as well," Jaenicke said. "But this study is the first to identify and analyze the level of food waste for individual households, which has been nearly impossible to estimate because comprehensive, current data on uneaten food at the household level do not exist."
The researchers overcame this limitation by borrowing methodology from the fields of production economics -- which models the production function of transforming inputs into outputs -- and nutritional science, by which a person's height, weight, gender and age can be used to calculate metabolic energy requirements to maintain body weight.
In this novel approach, Jaenicke and Yang Yu, doctoral candidate in agricultural, environmental and regional economics, analyzed data primarily from 4,000 households that participated in the U.S. Department of Agriculture's National Household Food Acquisition and Purchase Survey, known as FoodAPS. Food-acquisition data from this survey were treated as the "input."
FoodAPS also collected biological measures of participants, enabling the researchers to apply formulas from nutritional science to determine basal metabolic rates and calculate the energy required for household members to maintain body weight, which is the "output." The difference between the amount of food acquired and the amount needed to maintain body weight represents the production inefficiency in the model, which translates to uneaten, and therefore wasted, food.
"Based on our estimation, the average American household wastes 31.9% of the food it acquires," Jaenicke said. "More than two-thirds of households in our study have food-waste estimates of between 20% and 50%. However, even the least wasteful household wastes 8.7% of the food it acquires."
In addition, demographic data collected as part of the survey were used to analyze the differences in food waste among households with a variety of characteristics.
For example, households with higher income generate more waste, and those with healthier diets that include more perishable fruits and vegetables also waste more food, according to the researchers, who reported their findings in the American Journal of Agricultural Economics.
"It's possible that programs encouraging healthy diets may unintentionally lead to more waste," Jaenicke said. "That may be something to think about from a policy perspective -- how can we fine-tune these programs to reduce potential waste."
Household types associated with less food waste include those with greater food insecurity -- especially those that participate in the federal SNAP food assistance program, previously known as "food stamps" -- as well as those households with a larger number of members.
"People in larger households have more meal-management options," Jaenicke explained. "More people means leftover food is more likely to be eaten."
In addition, some grocery items are sold in sizes that may influence waste, he said.
"A household of two may not eat an entire head of cauliflower, so some could be wasted, whereas a larger household is more likely to eat all of it, perhaps at a single meal."
Among other households with lower levels of waste are those who use a shopping list when visiting the supermarket and those who must travel farther to reach their primary grocery store.
"This suggests that planning and food management are factors that influence the amount of wasted food," Jaenicke said.
Beyond the economic and nutritional implications, reducing food waste could be a factor in minimizing the effects of climate change. Previous studies have shown that throughout its life cycle, discarded food is a major source of greenhouse gas emissions, the researchers pointed out.
"According to the U.N. Food and Agriculture Organization, food waste is responsible for about 3.3 gigatons of greenhouse gas annually, which would be, if regarded as a country, the third-largest emitter of carbon after the U.S. and China," Jaenicke said.
The researchers suggested that this study can help fill the need for comprehensive food-waste estimates at the household level that can be generalized to a wide range of household groups.
"While the precise measurement of food waste is important, it may be equally important to investigate further how household-specific factors influence how much food is wasted," said Jaenicke. "We hope our methodology provides a new lens through which to analyze individual household food waste."
Read more at Science Daily
Researchers regrow damaged nerves with polymer and protein
University of Pittsburgh School of Medicine researchers have created a biodegradable nerve guide -- a polymer tube -- filled with growth-promoting protein that can regenerate long sections of damaged nerves, without the need for transplanting stem cells or a donor nerve.
So far, the technology has been tested in monkeys, and the results of those experiments appeared today in Science Translational Medicine.
"We're the first to show a nerve guide without any cells was able to bridge a large, 2-inch gap between the nerve stump and its target muscle," said senior author Kacey Marra, Ph.D., professor of plastic surgery at Pitt and core faculty at the McGowan Institute for Regenerative Medicine. "Our guide was comparable to, and in some ways better than, a nerve graft."
Half of wounded American soldiers return home with injuries to their arms and legs, which aren't well protected by body armor, often resulting in damaged nerves and disability. Among civilians, car crashes, machinery accidents, cancer treatment, diabetes and even birth trauma can cause significant nerve damage, affecting more than 20 million Americans.
Peripheral nerves can regrow up to a third of an inch on their own, but if the damaged section is longer than that, the nerve can't find its target. Often, the disoriented nerve gets knotted into a painful ball called a neuroma.
The most common treatment for longer segments of nerve damage is to remove a skinny sensory nerve at the back of the leg -- which causes numbness in the leg and other complications, but has the least chance of being missed -- chop it into thirds, bundle the pieces together and then sew them to the end of the damaged motor nerve, usually in the arm. But only about 40 to 60% of the motor function typically returns.
"It's like you're replacing a piece of linguini with a bundle of angel hair pasta," Marra said. "It just doesn't work as well."
Marra's nerve guide returned about 80% of fine motor control in the thumbs of four monkeys, each with a 2-inch nerve gap in the forearm.
The guide is made of the same material as dissolvable sutures and peppered with a growth-promoting protein -- the same one delivered to the brain in a recent Parkinson's trial -- which releases slowly over the course of months.
The experiment had two controls: an empty polymer tube and a nerve graft. Since monkeys' legs are relatively short, the usual clinical procedure of removing and dicing a leg nerve wouldn't work. So, the scientists removed a 2-inch segment of nerve from the forearm, flipped it around and sewed it into place, replacing linguini with linguini, and setting a high bar for the nerve guide to match.
Functional recovery was just as good with Marra's guide as it was with this best-case-scenario graft, and the guide outperformed the graft when it came to restoring nerve conduction and replenishing Schwann cells -- the insulating layer around nerves that boosts electrical signals and supports regeneration. In both scenarios, it took a year for the nerve to regrow. The empty guide performed significantly worse all around.
With these promising results in monkeys, Marra wants to bring her nerve guide to human patients. She's working with the Food and Drug Administration (FDA) on a first-in-human clinical trial and spinning out a startup company, AxoMax Technologies Inc.
Read more at Science Daily
So far, the technology has been tested in monkeys, and the results of those experiments appeared today in Science Translational Medicine.
"We're the first to show a nerve guide without any cells was able to bridge a large, 2-inch gap between the nerve stump and its target muscle," said senior author Kacey Marra, Ph.D., professor of plastic surgery at Pitt and core faculty at the McGowan Institute for Regenerative Medicine. "Our guide was comparable to, and in some ways better than, a nerve graft."
Half of wounded American soldiers return home with injuries to their arms and legs, which aren't well protected by body armor, often resulting in damaged nerves and disability. Among civilians, car crashes, machinery accidents, cancer treatment, diabetes and even birth trauma can cause significant nerve damage, affecting more than 20 million Americans.
Peripheral nerves can regrow up to a third of an inch on their own, but if the damaged section is longer than that, the nerve can't find its target. Often, the disoriented nerve gets knotted into a painful ball called a neuroma.
The most common treatment for longer segments of nerve damage is to remove a skinny sensory nerve at the back of the leg -- which causes numbness in the leg and other complications, but has the least chance of being missed -- chop it into thirds, bundle the pieces together and then sew them to the end of the damaged motor nerve, usually in the arm. But only about 40 to 60% of the motor function typically returns.
"It's like you're replacing a piece of linguini with a bundle of angel hair pasta," Marra said. "It just doesn't work as well."
Marra's nerve guide returned about 80% of fine motor control in the thumbs of four monkeys, each with a 2-inch nerve gap in the forearm.
The guide is made of the same material as dissolvable sutures and peppered with a growth-promoting protein -- the same one delivered to the brain in a recent Parkinson's trial -- which releases slowly over the course of months.
The experiment had two controls: an empty polymer tube and a nerve graft. Since monkeys' legs are relatively short, the usual clinical procedure of removing and dicing a leg nerve wouldn't work. So, the scientists removed a 2-inch segment of nerve from the forearm, flipped it around and sewed it into place, replacing linguini with linguini, and setting a high bar for the nerve guide to match.
Functional recovery was just as good with Marra's guide as it was with this best-case-scenario graft, and the guide outperformed the graft when it came to restoring nerve conduction and replenishing Schwann cells -- the insulating layer around nerves that boosts electrical signals and supports regeneration. In both scenarios, it took a year for the nerve to regrow. The empty guide performed significantly worse all around.
With these promising results in monkeys, Marra wants to bring her nerve guide to human patients. She's working with the Food and Drug Administration (FDA) on a first-in-human clinical trial and spinning out a startup company, AxoMax Technologies Inc.
Read more at Science Daily
Jan 23, 2020
How moon jellyfish get about
With their translucent bells, moon jellyfish (Aurelia aurita) move around the oceans in a very efficient way. Scientists at the University of Bonn have now used a mathematical model to investigate how these cnidarians manage to use their neural networks to control their locomotion even when they are injured. The results may also contribute to the optimization of underwater robots. The study has already been published online in the journal eLife; the final version will appear soon.
Moon jellyfish (Aurelia aurita) are common in almost all oceans. The cnidarians move about in the oceans with their translucent bells, which measure from three to 30 centimeters. "These jellyfish have ring-shaped muscles that contract, thereby pushing the water out of the bell," explains lead author Fabian Pallasdies from the Neural Network Dynamics and Computation research group at the Institute of Genetics at the University of Bonn.
Moon jellyfish are particularly efficient when it comes to getting around: They create vortices at the edge of their bell, which increase propulsion. Pallasdies: "Furthermore, only the contraction of the bell requires muscle power; the expansion happens automatically because the tissue is elastic and returns to its original shape."
Jellyfish for research into the origins of the nervous system
The scientists of the research group have now developed a mathematical model of the neural networks of moon jellyfish and used this to investigate how these networks regulate the movement of the animals. "Jellyfish are among the oldest and simplest organisms that move around in water," says the head of the research group, Prof. Dr. Raoul-Martin Memmesheimer. On the basis of them and other early organisms, the origins of the nervous system will now be investigated.
Especially in the 50s and 80s of the last century, extensive experimental neurophysiological data were obtained on jellyfish, providing the researchers at the University of Bonn with a basis for their mathematical model. In several steps, they considered individual nerve cells, nerve cell networks, the entire animal and the surrounding water. "The model can be used to answer the question of how the excitation of individual nerve cells results in the movement of the moon jellyfish," says Pallasdies.
The jellyfish can perceive their position with light stimuli and with a balance organ. If a moon jellyfish is turned by the ocean current, the animal compensates for this and moves further to the water surface, for example. With their model, the researchers were able to confirm the assumption that the jellyfish uses one neural network for swimming straight ahead and two for rotational movements.
Wave-shaped propagation of the excitation
The activity of the nerve cells spreads in the jellyfish's bell in a wave-like pattern. As experiments from the 19th century already show, the locomotion even works when large parts of the bell are injured. Scientists at the University of Bonn are now able to explain this phenomenon with their simulations: "Jellyfish can pick up and transmit signals on their bell at any point," says Pallasdies. When one nerve cell fires, the others fire as well, even if sections of the bell are impaired.
However, the wave-like propagation of the excitation in the jellyfish's bell would be disrupted if the nerve cells fired randomly. As the researchers have now discovered on the basis of their model, this risk is prevented by the nerve cells not being able to become active again so quickly after firing.
Read more at Science Daily
Moon jellyfish (Aurelia aurita) are common in almost all oceans. The cnidarians move about in the oceans with their translucent bells, which measure from three to 30 centimeters. "These jellyfish have ring-shaped muscles that contract, thereby pushing the water out of the bell," explains lead author Fabian Pallasdies from the Neural Network Dynamics and Computation research group at the Institute of Genetics at the University of Bonn.
Moon jellyfish are particularly efficient when it comes to getting around: They create vortices at the edge of their bell, which increase propulsion. Pallasdies: "Furthermore, only the contraction of the bell requires muscle power; the expansion happens automatically because the tissue is elastic and returns to its original shape."
Jellyfish for research into the origins of the nervous system
The scientists of the research group have now developed a mathematical model of the neural networks of moon jellyfish and used this to investigate how these networks regulate the movement of the animals. "Jellyfish are among the oldest and simplest organisms that move around in water," says the head of the research group, Prof. Dr. Raoul-Martin Memmesheimer. On the basis of them and other early organisms, the origins of the nervous system will now be investigated.
Especially in the 50s and 80s of the last century, extensive experimental neurophysiological data were obtained on jellyfish, providing the researchers at the University of Bonn with a basis for their mathematical model. In several steps, they considered individual nerve cells, nerve cell networks, the entire animal and the surrounding water. "The model can be used to answer the question of how the excitation of individual nerve cells results in the movement of the moon jellyfish," says Pallasdies.
The jellyfish can perceive their position with light stimuli and with a balance organ. If a moon jellyfish is turned by the ocean current, the animal compensates for this and moves further to the water surface, for example. With their model, the researchers were able to confirm the assumption that the jellyfish uses one neural network for swimming straight ahead and two for rotational movements.
Wave-shaped propagation of the excitation
The activity of the nerve cells spreads in the jellyfish's bell in a wave-like pattern. As experiments from the 19th century already show, the locomotion even works when large parts of the bell are injured. Scientists at the University of Bonn are now able to explain this phenomenon with their simulations: "Jellyfish can pick up and transmit signals on their bell at any point," says Pallasdies. When one nerve cell fires, the others fire as well, even if sections of the bell are impaired.
However, the wave-like propagation of the excitation in the jellyfish's bell would be disrupted if the nerve cells fired randomly. As the researchers have now discovered on the basis of their model, this risk is prevented by the nerve cells not being able to become active again so quickly after firing.
Read more at Science Daily
Inner complexity of Saturn moon, Enceladus, revealed
A Southwest Research Institute team developed a new geochemical model that reveals that carbon dioxide (CO2) from within Enceladus, an ocean-harboring moon of Saturn, may be controlled by chemical reactions at its seafloor. Studying the plume of gases and frozen sea spray released through cracks in the moon's icy surface suggests an interior more complex than previously thought.
"By understanding the composition of the plume, we can learn about what the ocean is like, how it got to be this way and whether it provides environments where life as we know it could survive," said SwRI's Dr. Christopher Glein, lead author of a paper in Geophysical Research Letters outlining the research. "We came up with a new technique for analyzing the plume composition to estimate the concentration of dissolved CO2 in the ocean. This enabled modeling to probe deeper interior processes."
Analysis of mass spectrometry data from NASA's Cassini spacecraft indicates that the abundance of CO2 is best explained by geochemical reactions between the moon's rocky core and liquid water from its subsurface ocean. Integrating this information with previous discoveries of silica and molecular hydrogen (H2) points to a more complex, geochemically diverse core.
"Based on our findings, Enceladus appears to demonstrate a massive carbon sequestration experiment," Glein said. "On Earth, climate scientists are exploring whether a similar process can be utilized to mitigate industrial emissions of CO2. Using two different data sets, we derived CO2 concentration ranges that are intriguingly similar to what would be expected from the dissolution and formation of certain mixtures of silicon- and carbon-bearing minerals at the seafloor."
Another phenomenon that contributes to this complexity is the likely presence of hydrothermal vents inside Enceladus. At Earth's ocean floor, hydrothermal vents emit hot, energy-rich, mineral-laden fluids that allow unique ecosystems teeming with unusual creatures to thrive.
"The dynamic interface of a complex core and seawater could potentially create energy sources that might support life," said SwRI's Dr. Hunter Waite, principal investigator of Cassini's Ion Neutral Mass Spectrometer (INMS). "While we have not found evidence of the presence of microbial life in the ocean of Enceladus, the growing evidence for chemical disequilibrium offers a tantalizing hint that habitable conditions could exist beneath the moon's icy crust."
The scientific community continues reaping the benefits of Cassini's close flyby of Enceladus on Oct. 28, 2015, prior to the end of the mission. INMS detected H2 as the spacecraft flew through the plume, and a different instrument had earlier detected tiny particles of silica, two chemicals that are considered to be markers for hydrothermal processes.
"Distinct sources of observed CO2, silica and H2 imply mineralogically and thermally diverse environments in a heterogeneous rocky core," Glein said. "We suggest that the core is composed of a carbonated upper layer and a serpentinized interior." Carbonates commonly occur as sedimentary rocks such as limestone on Earth, while serpentine minerals are formed from igneous seafloor rocks that are rich in magnesium and iron.
It is proposed that hydrothermal oxidation of reduced iron deep in the core creates H2, while hydrothermal activity intersecting quartz-bearing carbonated rocks produces silica-rich fluids. Such rocks also have potential to influence the CO2 chemistry of the ocean via low-temperature reactions involving silicates and carbonates at the seafloor.
Read more at Science Daily
"By understanding the composition of the plume, we can learn about what the ocean is like, how it got to be this way and whether it provides environments where life as we know it could survive," said SwRI's Dr. Christopher Glein, lead author of a paper in Geophysical Research Letters outlining the research. "We came up with a new technique for analyzing the plume composition to estimate the concentration of dissolved CO2 in the ocean. This enabled modeling to probe deeper interior processes."
Analysis of mass spectrometry data from NASA's Cassini spacecraft indicates that the abundance of CO2 is best explained by geochemical reactions between the moon's rocky core and liquid water from its subsurface ocean. Integrating this information with previous discoveries of silica and molecular hydrogen (H2) points to a more complex, geochemically diverse core.
"Based on our findings, Enceladus appears to demonstrate a massive carbon sequestration experiment," Glein said. "On Earth, climate scientists are exploring whether a similar process can be utilized to mitigate industrial emissions of CO2. Using two different data sets, we derived CO2 concentration ranges that are intriguingly similar to what would be expected from the dissolution and formation of certain mixtures of silicon- and carbon-bearing minerals at the seafloor."
Another phenomenon that contributes to this complexity is the likely presence of hydrothermal vents inside Enceladus. At Earth's ocean floor, hydrothermal vents emit hot, energy-rich, mineral-laden fluids that allow unique ecosystems teeming with unusual creatures to thrive.
"The dynamic interface of a complex core and seawater could potentially create energy sources that might support life," said SwRI's Dr. Hunter Waite, principal investigator of Cassini's Ion Neutral Mass Spectrometer (INMS). "While we have not found evidence of the presence of microbial life in the ocean of Enceladus, the growing evidence for chemical disequilibrium offers a tantalizing hint that habitable conditions could exist beneath the moon's icy crust."
The scientific community continues reaping the benefits of Cassini's close flyby of Enceladus on Oct. 28, 2015, prior to the end of the mission. INMS detected H2 as the spacecraft flew through the plume, and a different instrument had earlier detected tiny particles of silica, two chemicals that are considered to be markers for hydrothermal processes.
"Distinct sources of observed CO2, silica and H2 imply mineralogically and thermally diverse environments in a heterogeneous rocky core," Glein said. "We suggest that the core is composed of a carbonated upper layer and a serpentinized interior." Carbonates commonly occur as sedimentary rocks such as limestone on Earth, while serpentine minerals are formed from igneous seafloor rocks that are rich in magnesium and iron.
It is proposed that hydrothermal oxidation of reduced iron deep in the core creates H2, while hydrothermal activity intersecting quartz-bearing carbonated rocks produces silica-rich fluids. Such rocks also have potential to influence the CO2 chemistry of the ocean via low-temperature reactions involving silicates and carbonates at the seafloor.
Read more at Science Daily
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