DEMONOLOGY

Researchers discover a uniquely quantum effect in erasing information

TRINITY COLLEGE DUBLIN

Research News

 

IMAGE: A BIT OF INFORMATION CAN BE ENCODED IN THE POSITION OF A PARTICLE (LEFT OR RIGHT). A DEMON CAN ERASE A CLASSICAL BIT (BLUE) BY RAISING ONE SIDE UNTIL THE... view more 

CREDIT: PROFESSOR GOOLD, TRINITY COLLEGE DUBLIN

Researchers from Trinity College Dublin have discovered a uniquely quantum effect in erasing information that may have significant implications for the design of quantum computing chips. Their surprising discovery brings back to life the paradoxical "Maxwell's demon", which has tormented physicists for over 150 years.

The thermodynamics of computation was brought to the fore in 1961 when Rolf Landauer, then at IBM, discovered a relationship between the dissipation of heat and logically irreversible operations. Landauer is known for the mantra "Information is Physical", which reminds us that information is not abstract and is encoded on physical hardware.

The "bit" is the currency of information (it can be either 0 or 1) and Landauer discovered that when a bit is erased there is a minimum amount of heat released. This is known as Landauer's bound and is the definitive link between information theory and thermodynamics.

Professor John Goold's QuSys group at Trinity is analysing this topic with quantum computing in mind, where a quantum bit (a qubit, which can be 0 and 1 at the same time) is erased.

In just-published work in the journal, Physical Review Letters, the group discovered that the quantum nature of the information to be erased can lead to large deviations in the heat dissipation, which is not present in conventional bit erasure.

Thermodynamics and Maxwell's demon

One hundred years previous to Landauer's discovery people like Viennese scientist, Ludwig Boltzmann, and Scottish physicist, James Clerk Maxwell, were formulating the kinetic theory of gases, reviving an old idea of the ancient Greeks by thinking about matter being made of atoms and deriving macroscopic thermodynamics from microscopic dynamics.

Professor Goold says:

"Statistical mechanics tells us that things like pressure and temperature, and even the laws of thermodynamics themselves, can be understood by the average behavior of the atomic constituents of matter. The second law of thermodynamics concerns something called entropy which, in a nutshell, is a measure of the disorder in a process. The second law tells us that in the absence of external intervention, all processes in the universe tend, on average, to increase their entropy and reach a state known as thermal equilibrium.

"It tells us that, when mixed, two gases at different temperatures will reach a new state of equilibrium at the average temperature of the two. It is the ultimate law in the sense that every dynamical system is subject to it. There is no escape: all things will reach equilibrium, even you!"

However, the founding fathers of statistical mechanics were trying to pick holes in the second law right from the beginning of the kinetic theory. Consider again the example of a gas in equilibrium: Maxwell imagined a hypothetical "neat-fingered" being with the ability to track and sort particles in a gas based on their speed.

Maxwell's demon, as the being became known, could quickly open and shut a trap door in a box containing a gas, and let hot particles through to one side of the box but restrict cold ones to the other. This scenario seems to contradict the second law of thermodynamics as the overall entropy appears to decrease and perhaps physics' most famous paradox was born.

But what about Landauer's discovery about the heat-dissipated cost of erasing information? Well, it took another 20 years until that was fully appreciated, the paradox solved, and Maxwell's demon finally exorcised.

Landauer's work inspired Charlie Bennett - also at IBM - to investigate the idea of reversible computing. In 1982 Bennett argued that the demon must have a memory, and that it is not the measurement but the erasure of the information in the demon's memory which is the act that restores the second law in the paradox. And, as a result, computation thermodynamics was born.

New findings

Now, 40 years on, this is where the new work led by Professor Goold's group comes to the fore, with the spotlight on quantum computation thermodynamics.

In the recent paper, published with collaborator Harry Miller at the University of Manchester and two postdoctoral fellows in the QuSys Group at Trinity, Mark Mitchison and Giacomo Guarnieri, the team studied very carefully an experimentally realistic erasure process that allows for quantum superposition (the qubit can be in state 0 and 1 at same time).

Professor Goold explains:

"In reality, computers function well away from Landauer's bound for heat dissipation because they are not perfect systems. However, it is still important to think about the bound because as the miniaturisation of computing components continues, that bound becomes ever closer, and it is becoming more relevant for quantum computing machines. What is amazing is that with technology these days you can really study erasure approaching that limit.

"We asked: 'what difference does this distinctly quantum feature make for the erasure protocol?' And the answer was something we did not expect. We found that even in an ideal erasure protocol - due to quantum superposition - you get very rare events which dissipate heat far greater than the Landauer limit.

"In the paper we prove mathematically that these events exist and are a uniquely quantum feature. This is a highly unusual finding that could be really important for heat management on future quantum chips - although there is much more work to be done, in particular in analysing faster operations and the thermodynamics of other gate implementations.

"Even in 2020, Maxwell's demon continues to pose fundamental questions about the laws of nature."

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The journal article is available at: https://bit.ly/2FwH8aF

 

The mental health impact of pandemics for front line health care staff

UNIVERSITY OF EAST ANGLIA

Research News

 

Mental health problems such as Post-Traumatic Stress Disorder, anxiety and depression are common among healthcare staff during and immediately after pandemics - according to new research from the University of East Anglia.

Researchers investigated how treating patients in past pandemics such as SARS and MERS affected the mental health of front-line staff.

They found that almost a quarter of health-care workers (23.4 per cent) experienced PTSD symptoms during the most intense 'acute' phase of previous pandemic outbreaks - with 11.9 per cent of carers still experiencing symptoms a year on.

They also looked at data about elevated levels of mental distress and found that more than a third of health workers (34.1 per cent) experienced symptoms such as anxiety or depression during the acute phase, dropping to 17.9 per cent after six months. This figure however increased again to 29.3 per cent after 12 months or longer.

The team hope that their work will help highlight the impact that the Covid-19 pandemic could be having on the mental health of doctors and nurses around the world.

Prof Richard Meiser-Stedman, from UEA's Norwich Medical School, said: "We know that Covid-19 poses unprecedented challenges to the NHS and to healthcare staff worldwide.

"Nurses, doctors, allied health professionals and all support staff based in hospitals where patients with Covid-19 are treated are facing considerable pressure, over a sustained period.

"In addition to the challenge of treating a large volume of severely unwell patients, front line staff also have to contend with threats to their own physical health through infection, particularly as they have had to face shortages of essential personal protective equipment.

"The media has reported that healthcare workers treating coronavirus patients will face a 'tsunami' of mental health problems as a result of their work.

"We wanted to examine this by looking closely at the existing data from previous pandemics to better understand the potential impact of Covid-19.

"We estimated the prevalence of common mental health disorders in health care workers based in pandemic-affected hospitals. And we hope our work will help inform hospital managers of the level of resources required to support staff through these difficult times."

A team of trainee clinical psychologists - Sophie Allan, Rebecca Bealey, Jennifer Birch, Toby Cushing, Sheryl Parke and Georgina Sergi - all from UEA's Norwich Medical School, investigated how previous pandemics affected healthcare workers' mental health, with support from Prof Meiser-Stedman and Dr Michael Bloomfield, University College London.

They looked at 19 studies which included data predominantly from the SARS outbreak in Asia and Canada, and which tended to focus on the acute stage of the pandemic - during and up to around six weeks after the pandemic.

Sophie Allan said: "We found that post-traumatic stress symptoms were elevated during the acute phase of a pandemic and at 12 months post-pandemic.

"There is some evidence that some mental health symptoms such as Post Traumatic Stress symptoms get better naturally over time but we cannot be sure about this. The studies we looked at had very different methods - for example they used different questionnaires about mental health - so we need to be cautious about the results.

"We didn't find any differences between doctors and nurses experiencing PTSD or other psychiatric conditions, but the available data was limited and more research is needed to explore this.

"Overall there are not enough studies examining the impact of pandemics on the mental health of healthcare staff. More research is needed that focusses on Covid-19 specifically and looks at the mental health of healthcare workers longer-term," she added.

'The prevalence of common and stress-related mental health disorders in healthcare workers based in pandemic-affected hospitals: a rapid systematic review and meta-analysis' is published in the European Journal of Psychotraumatology on October 16, 2020.

 

Humans and climate drove giants of Madagascar to extinction

UNIVERSITY OF INNSBRUCK

Research News

 

IMAGE: INVESTIGATING THE DRIVERS OF EXTINCTION: BY ANALYZING STALAGMITES FROM THE LA VIERGE CAVE LOCATED ON RODRIGUES THE SCIENTISTS RECONSTRUCTED 8000 YEARS OF THE REGION'S PAST CLIMATE. view more 

CREDIT: HANYING LI

Nearly all of Madagascan megafauna - including the famous Dodo bird, gorilla-sized lemurs, giant tortoises, and the Elephant Bird which stood 3 meters tall and weighted close to a half ton - vanished between 1500 and 500 years ago. Were these animals overhunted to extinction by humans? Or did they disappear because of climate change? There are numerous hypotheses, but the exact cause of this megafauna crash remains elusive and hotly debated. The Mascarene islands east of Madagascar are of special interest because they are among the last islands on earth to be colonized by humans. Intriguingly, the islands' megafauna crashed in just a couple of centuries following human settlement. In a recent study published by Science Advances, a team of international researchers found that it was likely a "double whammy" of heightened human activities in combination with a particularly severe spell of region-wide aridity that may have doomed the megafauna. The researchers rule out climate change as the one and only cause, and instead suggest that the impact of human colonization was a crucial contributor to the megafaunal collapse. Hanying Li, a postdoctoral scholar at the Xi'an Jiaotong University in China and the lead author of this study, pieced together a detailed history of the regional climate variations. The primary source of this new paleoclimate record came from the tiny Mascarene island of Rodrigues in the southwest Indian Ocean approximately 1600 km east of Madagascar. "An island so remote and small that one will not find it on most schoolbook atlases," says Gayatri Kathayat, one of the co-authors and an associate professor of climate science at Xi'an Jiaotong University.

Analysis of Cave Deposits

Li and colleagues built their climate records by analyzing the trace elements and carbon and oxygen isotopes from each incremental growth layer of stalagmites which they collected from one of the many caves from this island. The bulk of these analyses were conducted at the Quaternary Research Group at the Institute of Geology at the University of Innsbruck, led by Prof. Christoph Spötl: "Variations in the geochemical signatures provided the information needed to reconstruct the region's rainfall patterns over the last 8000 years. To analyze the stalagmites we used the stable isotope method in our lab in Innsbruck". Despite the distance between the two islands, the summer rainfall at Rodrigues and Madagascar is influenced by the same global-wide tropical rain belt that oscillates north and south with the seasons." And when this belt falters and stays further north of Rodrigues, droughts can strike the whole region from Madagascar to Rodrigues," Hai Cheng explains, the study's senior coauthor. "Li's work from Rodrigues demonstrates that the hydroclimate of the region experienced a series of drying trends throughout the last 8 millennia, which were frequently punctuated by 'megadroughts' that lasted for decades," notes Hubert Vonhof, scientist at Max Planck Institute of Chemistry in Mainz, Germany and coauthor.

Resilient to climate stress

The most recent of the drying trends in the region commenced around 1500 years ago at a time when the archaeological and proxy records began to show definitive signs of increased human presence on the island. "While we cannot say with 100 percent certainty whether human activity, such as overhunting or habitat destruction, was the proverbial last straw that broke the camel's back, our paleoclimate records make a strong case that the megafauna had survived through all the previous episodes of even greater aridity. This resilience to past climate swings suggests that an additional stressor contributed to the elimination of the region's megafauna," notes Ashish Sinha, professor of earth science at California State University Dominguez Hills, USA. "There are still many pieces missing to fully solve the riddle of megafauna collapse. This study now provides an important multi-millennial climatic context to megafaunal extinction," says Ny Rivao Voarintsoa from KU Leuven in Belgium, a native of Madagascar, who participated in this research. The study sheds new light on the decimation of flora and fauna of Mauritius and Rodrigues: "Both islands were rapidly stripped of endemic species of vertebrates within two centuries of the initial human colonization, including the well-known flightless 'Dodo' bird from Mauritius and the saddle-backed 'Rodrigues giant tortoise' endemic to Rodrigues," adds Aurele Anquetil André, the reserve manager and chief conservator at the Francois Leguat Giant Tortoise and Cave Reserve at Rodrigues.

"The story our data tells is one of resilience and adaptability of the islands' ecosystems and fauna in enduring past episodes of severe climate swings for eons - until they were hit by human activities and climate change", the researchers conclude.

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Publication:

H. Li, A. Sinha, A. Anquetil André, C. Spötl, H. B. Vonhof, A. Meunier, G. Kathayat, P. Duan, N. R. G. Voarintsoa, Y. Ning, J. Biswas, P. Hu, X. Li, L. Sha, J. Zhao, R. L. Edwards, H. Cheng, A multimillennial climatic context for the megafaunal extinctions in Madagascar and Mascarene Islands. Sci. Adv. 6, eabb2459 (2020).

DOI: 10.1126/sciadv.abb2459

 

Explaining teamwork in male lions

UNIVERSITY OF MINNESOTA

Research News

 

Animal cooperation typically involves sharing crucial resources -- and the rules of sharing get complicated, especially when males are involved.

Natural selection theory dictates that males generally compete with each other for food and mates. Thus male cooperation in the animal world is an enigma, especially among unrelated animals.

In a new paper published in Scientific Reports, biologists from the Wildlife Institute of India and the University of Minnesota demonstrated the hows and whys of cooperation among male lions. By studying one of the rarest lion populations in the world -- the Asian lions that live as a single population in the Gir Forest of India -- researchers found that cooperation among lions does not necessarily indicate that they are related.

"In a 2017 study, we detailed the behavioural nuances of why male lions cooperate: to better protect their territories and have more access to mating opportunities than males who live alone," said study lead author Stotra Chakrabarti, a postdoctoral research associate in the Department of Fisheries, Wildlife, and Conservation Biology at the University of Minnesota. "However, a lack of genetic data from the population at this stage had prevented us from determining if such cooperation extended to relatives only, or whether non-kin were included as well."

Subsequent monitoring of individual lions and collection of tissue, hair and blood samples from known individuals set the stage to find out whether the cooperating males were related or they came together by chance.

"Genetic analyses of the Gir lions were tricky because they have undergone two population bottlenecks that have rendered discerning kin versus non-kin quite challenging," said Vishnupriya Kolipakam, co-author and faculty at the Wildlife Institute of India..

By synthesizing long-term behavioural and genetic records of known mothers, offspring and siblings, researchers were able to develop a baseline panel against which male coalition partners were compared to understand the level of relatedness between them.

By observing 23 male lions belonging to 10 coalitions, Chakrabarti and co-authors could identify that males who lived in large coalitions (such as trios and quartets) were typically brothers and cousins, but more than 70 percent of pairs consisted of unrelated males.

In large coalitions, sharing is costlier because resources are divided between many lions, and often low-ranking partners are excluded from opportunities to breed. Such coalitions are only possible between related animals.

"Forgoing mating opportunities is generally a severe evolutionary cost, unless in doing so you help related individuals," said Joseph Bump, co-author and associate professor at the University of Minnesota. "As a consequence, this evidence supports a conclusion that large male lion coalitions are feasible only when all partners are brothers and/or cousins."

Large coalitions fared the best as a group, but the fitness of individual lions -- measured by the number of potential offspring sired -- was higher in pairs. Such high fitness for individual male lions in pairs allowed even unrelated individuals to team up, because pairs always fared better than single males in terms of territory and mate acquisition.

"The results of our study show that male coalitions prosper better than loners in established lion societies and this can have crucial implications for their conservation, especially when establishing new populations through reintroductions," said YV Jhala, principal investigator of the Gir lion project and the Dean of the Wildlife Institute of India.

Though large coalitions fared better as a group, they are rare in the Gir system because so few sets of sibling lions grow to maturity. An analysis of 20 years of lion demography data indicates only 12%-13% of the observed lion coalitions in Gir are made of three or four males.

"This calculation of demography and the availability of kin to support cooperation is often missing from studies on animal societies, but it is of fundamental value that enhances our understanding of how optimality in group formation is constrained in the real world," Jhala said.

The study revealed new details about the behavior of male lions. For example, in a rare observation, researchers determined one of the study's coalitions could be a father-son duo because they were related and had an age difference of about five years.

"Such an observation was only possible because we could combine field observations with genetic data, and it shows that there could be multiple pathways for coalition formation in lions," said Kolipakam.

Researchers also observed that related male partners were no more likely to support each other during fights with rivals than unrelated partners.

"This shows that kin support is not the only reason why males cooperate with each other, but kin support makes the cooperation even more beneficial," Bump said.

The study indicates that underlying mechanisms facilitating cooperation in lions can be multifaceted.

"We have quantified the ultimate reasons why unrelated males team up, but it would be worthwhile to investigate other aspects of male cooperation, including how their bonds are forged in the first place, how they find compatible partners, what breaks the ice between them when they first meet and how they decide who will lead and who will follow." Chakrabarti said.

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COVID: women are less likely to put themselves in danger

Women's attitudes and behaviors may have contributed to their reduced vulnerability and mortality. A survey in 8 countries shows they consider Coronavirus a more serious problem than men and are more likely to approve and comply with health policies

BOCCONI UNIVERSITY

Research News

 

IMAGE: PAOLA PROFETA view more 

CREDIT: PAOLO TONATO

The increased adherence of women to Coronavirus policies may be one of the reasons for the lower vulnerability and mortality that they experienced, compared to men, in the early phase of the epidemic. "Policy makers who promote a new normality made of reduced mobility, face masks and other behavioral changes," says Vincenzo Galasso, one of the authors of a new study on gender differences in the reaction to COVID-19, "should, therefore, design a gender-differentiated communication if they want to increase the compliance of men."

Two of the authors of the research, which appeared on PNAS (Proceedings of the National Academy of Sciences) are scholars of Bocconi University, Vincenzo Galasso and Paola Profeta, affiliated to Bocconi's COVID Crisis Lab.

The authors observe substantial gender differences in both attitudes and behaviors through a two-wave survey (March and April 2020), with 21,649 respondents in Australia, Austria, France, Germany, Italy, New Zealand, the UK and the US, which is part of the international project REPEAT (REpresentations, PErceptions and ATtitudes on the COVID-19).

Women around the world are more inclined than men to consider COVID-19 a very serious health problem (59% against 48.7% in March and 39.6% against 33% in April), they are more inclined to agree with public policies that fight the pandemic, such as mobility restrictions and social distancing (54,1 against 47,7 in an index that goes from 1 to 100 in March and 42,6 against 37,4 in April) and are clearly more inclined to follow the rules concerning COVID-19 (88,1% against 83,2% in March and 77,6% against 71,8% in April).

The share of individuals complying with the rules drops over time, particularly in Germany, from 85.8% of women and 81.5% of men in March to 70.5% of women and 63.7% of men in April, but the large gender gap persists.

"The biggest differences between men and women relate to behaviors that serve to protect others above all, such as coughing in the elbow, unlike those that can protect both themselves and others," says Profeta. Gender differences persist even after the study controlled a large number of sociodemographic characteristics and psychological factors.

However, such differences are smaller among married couples, who live together and share their views with each other, and among individuals most directly exposed to the pandemic. They decrease over time if men and women are exposed to the same flow of information about the pandemic.

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Non-obese Vietnamese Americans are 60% more likely to have diabetes

Study compares non-obese Vietnamese Americans with non-obese, non-Hispanic White Americans

UNIVERSITY OF TORONTO

Research News

 

A new study has found that Vietnamese-American adults who were not obese were 60% more likely to have diabetes than non-obese, non-Hispanic, White Americans, after accounting for age, sex, sociodemographic factors, smoking history and exercise level.

Overall, only 9% of Vietnamese Americans with diabetes in the study were obese -- defined as having a body mass index (BMI) of 30 or higher. In comparison, half of all non-Hispanic White Americans with diabetes were obese.

"While obesity is commonly associated with diabetes risk, the study's findings indicate that this is not necessarily the case for Vietnamese Americans," says the study's first author Leanne R. De Souza, Assistant Professor, Human Biology and Health Studies Programs, University College, University of Toronto. "As a result, health care professionals may miss screening for preventing and treating this potentially life-threatening disease in the Vietnamese-American population. Screening of Vietnamese adults who have normal weight would be helpful."

The data set used in this study did not provide information on why non-obese Vietnamese Americans have higher odds of diabetes than White Americans, but previous research provides potential answers.

Other studies have found that accumulation of excess fat in the abdomen is higher among Asian Americans than White Americans of a similar weight.

"A growing body of literature suggests that measurement of excess weight around the liver and in the abdomen may be a better way to assess diabetes risk than merely taking into account weight and height," says co-author Keith Tsz-Kit Chan, Assistant Professor, Silberman School of Social Work at Hunter College, City University of New York.

Past research has also shown that Asian Americans are less likely to be screened and are therefore more likely to be living with undiagnosed diabetes and pre-diabetes. Untreated diabetes can result in many serious complications including nerve damage, preventable amputation, blindness, heart attacks, strokes, chronic kidney disease and kidney failure.

The authors of the present study found that among non-obese Vietnamese Americans, those aged 45 and older had at least 40-fold the odds of diabetes compared to young adults.

"These findings suggest that screening for diabetes in Vietnamese Americans starting at age 45 might be warranted," says co-author Alexis Karasiuk, a research assistant at the University of Toronto.

In the subsample of non-obese Vietnamese Americans, men and those living in poverty had a much higher prevalence of diabetes compared to women and those with higher incomes, respectively. Adults who had never smoked and those with a post-secondary degree were less likely to have diabetes.

The authors hope to examine the role of diet in future studies.

"Previous research has found that each additional portion of white rice consumed daily raises the risk of diabetes by 11%. Substituting other whole grains such as brown rice instead of white rice may be a promising strategy for decreasing this risk," noted co-author Karen Kobayashi, professor in the department of Sociology and a research fellow at the Institute on Aging & Lifelong Health at the University of Victoria.

Given that non-obese Vietnamese Americans, including those as young as 45, have a relatively high prevalence of diabetes, the authors say that routine screening of this population is needed.

"Better identification of those in the 'pre-diabetes' stage may increase awareness of personal risk and interventions to promote lifestyle changes. Such interventions may substantially decrease the risk of progression to full diabetes," says senior author, Esme Fuller-Thomson, Director of the Institute for Life Course & Aging and professor at the University of Toronto's Factor-Inwentash Faculty of Social Work and Department of Family & Community Medicine.

The author's study was based upon a representative sample of community-dwelling Californians aged 18 and older from seven combined waves of the California Health Interview Survey (CHIS) conducted between 2007 and 2016. The study sample was restricted to Vietnamese Americans (n = 3,969) and non-Hispanic whites (n = 119,651) who were non-obese, defined as having a body mass index (BMI) of less than 30.

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The study was published online ahead of press in the journal Chronic Illness.

Source Article:

De Souza LR, Chan, KT, Kobayashi, K, Karasiuk, A, Fuller-Thomson, E (2020). The prevalence and management of diabetes among Vietnamese Americans: A population-based survey of an understudied ethnic group

For interviews please contact first author, Leanne De Souza leanne.desouza@utoronto.ca or 647-787-3507, or senior author, Esme Fuller-Thomson, esme.fuller.thomson@utoronto.ca or 416 209-3231

A copy of the paper is available to credentialed journalist upon request.

 

Arctic Ocean sediments reveal permafrost thawing during past climate warming

STOCKHOLM UNIVERSITY

Research News

 

IMAGE: RIGGING GRAVITY CORER ON THE DECK OF ICEBREAKER ODEN ON SWERUS-C3 EXPEDITION 2014. view more 

CREDIT: BJÖRN ERIKSSON

Sea floor sediments of the Arctic Ocean can help scientists understand how permafrost responds to climate warming. A multidisciplinary team from Stockholm University has found evidence of past permafrost thawing during climate warming events at the end of the last ice age. Their findings, published in Science Advances, caution about what could happen in the near future: That Arctic warming by only a few degrees Celsius may trigger massive permafrost thawing, coastal erosion, and the release of the greenhouse gases carbon dioxide (CO2) and methane (CH4) into the atmosphere.

Arctic permafrost stores more carbon than the atmosphere does. When permafrost thaws, this carbon may be converted to greenhouse gases (CO2 and CH4) that then enter the atmosphere and may affect the climate system. To improve predictions of future greenhouse gas emissions from permafrost, scientists have started to look into the past, exploring how previous climate warming, for example at the end of the last ice age, affected permafrost and its vast pool of carbon.

"Our new study shows for the first time the full history of how warming at the end of the last ice age triggered permafrost thawing in Siberia. This also suggests the release of large quantities of greenhouse gases," says Jannik Martens, PhD student at Stockholm University and lead author of the study. "It appears likely that past permafrost thawing at times of climate warming, about 14,700 and 11,700 years ago, was in part also related to the increase in CO2 concentrations that is seen in Antarctic ice cores for these times. It seems that Arctic warming by only a few degrees Celsius is sufficient to disturb large areas covered by permafrost and potentially affect the climate system."

In the current study, the scientists used an eight meters long sediment core that was recovered from the sea floor more than 1 000 meters below the surface of the Arctic Ocean during the SWERUS-C3 expedition onboard the Swedish icebreaker Oden back in 2014. To reconstruct permafrost thawing on land, the scientists applied radiocarbon (14C) dating and molecular analysis to trace organic remains that once were released by thawing permafrost and then washed into the Arctic Ocean.

"From this core we also learned that erosion of permafrost coastlines was an important driving force for permafrost destruction at the end of the last ice age. Coastal erosion continues to the present day, though ten times slower than during these earlier rapid warming period. With the recent warming trends, however, we see again an acceleration of coastal erosion in some parts of the Arctic, which is expected to release greenhouse gases by degradation of the released organic matter," says Örjan Gustafsson, Professor at Stockholm University and leader of the research program. "Any release from thawing permafrost mean that there is even less room for anthropogenic greenhouse gas release in the earth-climate system budget before dangerous thresholds are reached. The only way to limit permafrost-related greenhouse gas releases is to mitigate climate warming by lowering anthropogenic greenhouse gas emissions."

Gustafsson, Martens and their colleagues are now again in the Arctic Ocean as part of the International Siberian Shelf Study (ISSS-2020) onboard the Russian research vessel Akademik Keldysh. The expedition left the port of Arkhangelsk on September 26 and is currently in the East Siberian Sea, seeking more answers to how changing climate may trigger release of carbon, including greenhouse gases, from Arctic permafrost systems, including coastal erosion and permafrost below the sea bottom preserved from the past ice age.

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Publication:

J. Martens, B. Wild, F. Muschitiello, M. O'Regan, M. Jakobsson, I. Semiletov, O. V. Dudarev, &. Gustafsson, Remobilization of dormant carbon from Siberian-Arctic permafrost during three past warming events. Sci. Adv. 6, eabb6546 (2020).

For further information, please contact:

Jannik Martens, Doctoral candidate at Stockholm University, jannik.martens@aces.su.se

Örjan Gustafsson, Professor in Biogeochemistry at Stockholm University, ojan.gustafsson@aces.su.se

Please note! Changes in e-mail addresses due to the ongoing ISSS-2020 expedition.

With regard to the ISSS-2020 Arctic Ocean expedition (Sep 23 - Nov 06), Jannik Martens will coordinate any inquiries regarding this publication via the temporary e-mail address jannikmartens@myiridium.net

Please direct all e-mail correspondence for the time during the expedition to this address and also keep the primary SU address jannik.martens@aces.su.se in CC.

Please know that file attachments sent to jannikmartens@myiridium.net should not be larger than 300 kb and expect that file attachments sent from this address cannot be larger than 100 kb.

Short interviews via satellite phone with either Jannik Martens or Örjan Gustafsson are possible upon request or audio commentary may be recorded and transmitted electronically via e-mail.

More information about the ISSS-2020 expedition may be found here: https://www.aces.su.se/research/projects/the-isss-2020-arctic-ocean-expedition/

 

Study explains the process that exacerbates MS

KAROLINSKA INSTITUTET

Research News

 

IMAGE: RESEARCH GROUP, FROM THE LEFT: ANDRÉ ORTLIEB GUERREIRO-CACAIS (RESEARCHER), MAJA JAGODIC (DOCENT AND GROUP LEADER FOR RESEARCH ON MS EPIGENETICS), RASMUS BERGLUND (DOCTORAL STUDENT), AND TOMAS OLSSON (PROFESSOR). view more 

CREDIT: ULF SIRBORN

People with multiple sclerosis (MS) gradually develop increasing functional impairment. Researchers at Karolinska Institutet have now found a possible explanation for the progressive course of the disease in mice and how it can be reversed. The study, which is published in Science Immunology, can prove valuable to future treatments.

MS is a chronic inflammatory disease of the central nervous system (CNS) and one of the main causes of neurological functional impairment.

The disease is generally diagnosed between 20 and 30 years of age. It can cause severe neurological symptoms, such as loss of sensation and trembling, difficulties walking and maintaining balance, memory failure and visual impairment.

MS is a life-long disease with symptoms that most often gradually worsen over time.

In the majority of cases the disease comes in bouts with a certain amount of subsequent recovery. A gradual loss of function with time is, however, inevitable. Research has made great progress in treatments that reduce the frequency and damaging effects of these bouts.

"Despite these important breakthroughs, the disease generally worsens when the patient has had it for 10 to 20 years," says Maja Jagodic, docent of experimental medicine at the Department of Clinical Neuroscience and the Centre for Molecular Medicine, Karolinska Institutet. "There is currently only one, recently approved, treatment for what is called the secondary progressive phase. The mechanisms behind this progressive phase require more research."

Researchers at Karolinska Institutet have now shown that recovery from MS-like symptoms in mice depends on the ability of the CNS's own immune cells - microglia - to break down the remains of damaged cells, such as myelin.

The processes was interrupted when the researchers removed a so-called autophagy gene, Atg7. Autophagy is a process where cells normally break down and recycle their own proteins and other structural components.

Without Atg7 the ability of the microglia to clean away tissue residues created by the inflammation was reduced. These residues accumulated over time, which is a possible explanation for the progressiveness of the disease.

The study also shows how microglia from aged mice resemble the cells from young mice that lacked Atg7 in terms of deficiencies in this process, which had a negative effect on the course of the disease.

This is a significant result since increasing age is an important risk factor in the progressive phase of MS. The researchers also show how this process can be reversed.

"The plant and fungi-derived sugar Trehalose restores the functional breakdown of myelin residues, stops the progression and leads to recovery from MS-like disease." says doctoral student Rasmus Berglund. "By enhancing this process we hope one day to be able to treat and prevent age-related aspects of neuroinflammatory conditions."

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The research was carried out with grants from the Swedish Research Council, the Swedish Brain Foundation, Neuro, Region Stockholm, Astra Zeneca, Horizon 2020, the European Research Council, the Knut and Alice Wallenberg Foundation, the Margaretha af Uggla Foundation, Alltid Litt Sterkere, the Foundation of Swedish MS research, NEURO Sweden and Karolinska Institutet. There are no declared conflicts of interest.

Publication: "Microglial autophagy-associated phagocytosis is essential for recovery from neuroinflammation". Rasmus Berglund, Andre Ortlieb Guerreiro-Cacais, Milena Z. Adzemovic, Manuel Zeitelhofer, Harald Lund, Ewoud Ewing, Sabrina Ruhrmann, Erik Nutma, Roham Parsa, Melanie Thessen-Hedreul, Sandra Amor, Robert A. Harris, Tomas Olsson and Maja Jagodic. Science Immunology, 16 October 2020, doi: 10.1126/sciimmunol.abb5077.

A controllable membrane to pull carbon dioxide out of exhaust streams

Electrically switchable system could continuously separate gases without the need for moving parts or wasted space

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Research News

A new system developed by chemical engineers at MIT could provide a way of continuously removing carbon dioxide from a stream of waste gases, or even from the air. The key component is an electrochemically assisted membrane whose permeability to gas can be switched on and off at will, using no moving parts and relatively little energy.

The membranes themselves, made of anodized aluminum oxide, have a honeycomb-like structure made up of hexagonal openings that allow gas molecules to flow in and out when in the open state. However, gas passage can be blocked when a thin layer of metal is electrically deposited to cover the pores of the membrane. The work is described in the journal Science Advances, in a paper by Professor T. Alan Hatton, postdoc Yayuan Liu, and four others.

This new "gas gating" mechanism could be applied to the continuous removal of carbon dioxide from a range of industrial exhaust streams and from ambient air, the team says. They have built a proof-of-concept device to show this process in action.

The device uses a redox-active carbon-absorbing material, sandwiched between two switchable gas gating membranes. The sorbent and the gating membranes are in close contact with each other and are immersed in an organic electrolyte to provide a medium for zinc ions to shuttle back and forth. These two gating membranes can be opened or closed electrically by switching the polarity of a voltage between them, causing ions of zinc to shuttle from one side to the other. The ions simultaneously block one side, by forming a metallic film over it, while opening the other, by dissolving its film away.

When the sorbent layer is open to the side where the waste gases are flowing by, the material readily soaks up carbon dioxide until it reaches its capacity. The voltage can then be switched to block off the feed side and open up the other side, where a concentrated stream of nearly pure carbon dioxide is released.

By building a system with alternating sections of membrane that operate in opposite phases, the system would allow for continuous operation in a setting such as an industrial scrubber. At any one time, half of the sections would be absorbing the gas while the other half would be releasing it.

"That means that you have a feed stream coming into the system at one end and the product stream leaving from the other in an ostensibly continuous operation," Hatton says. "This approach avoids many process issues" that would be involved in a traditional multicolumn system, in which adsorption beds alternately need to be shut down, purged, and then regenerated, before being exposed again to the feed gas to begin the next adsorption cycle. In the new system, the purging steps are not required, and the steps all occur cleanly within the unit itself.

The researchers' key innovation was using electroplating as a way to open and close the pores in a material. Along the way the team had tried a variety of other approaches to reversibly close pores in a membrane material, such as using tiny magnetic spheres that could be positioned to block funnel-shaped openings, but these other methods didn't prove to be efficient enough. Metal thin films can be particularly effective as gas barriers, and the ultrathin layer used in the new system requires a minimal amount of the zinc material, which is abundant and inexpensive.

"It makes a very uniform coating layer with a minimum amount of materials," Liu says. One significant advantage of the electroplating method is that once the condition is changed, whether in the open or closed position, it requires no energy input to maintain that state. Energy is only required to switch back again.

Potentially, such a system could make an important contribution toward limiting emissions of greenhouse gases into the atmosphere, and even direct-air capture of carbon dioxide that has already been emitted.

While the team's initial focus was on the challenge of separating carbon dioxide from a stream of gases, the system could actually be adapted to a wide variety of chemical separation and purification processes, Hatton says.

"We're pretty excited about the gating mechanism. I think we can use it in a variety of applications, in different configurations," he says. "Maybe in microfluidic devices, or maybe we could use it to control the gas composition for a chemical reaction. There are many different possibilities."

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The research team included graduate student Chun-Man Chow, postdoc Katherine Phillips, and recent graduates Miao Wang PhD '20 and Sahag Voskian PhD '19. The work was supported by ExxonMobil.

Written by David L. Chandler, MIT News Office

 

When good governments go bad

History shows that societies collapse when leaders undermine social contracts

FIELD MUSEUM

Research News

 

IMAGE: THE RUINS OF THE ROMAN FORUM, ONCE A SITE OF A REPRESENTATIONAL GOVERNMENT. view more 

CREDIT: (C) LINDA NICHOLAS, FIELD MUSEUM

All good things must come to an end. Whether societies are ruled by ruthless dictators or more well-meaning representatives, they fall apart in time, with different degrees of severity. In a new paper, anthropologists examined a broad, global sample of 30 pre-modern societies. They found that when "good" governments--ones that provided goods and services for their people and did not starkly concentrate wealth and power--fell apart, they broke down more intensely than collapsing despotic regimes. And the researchers found a common thread in the collapse of good governments: leaders who undermined and broke from upholding core societal principles, morals, and ideals.

"Pre-modern states were not that different from modern ones. Some pre-modern states had good governance and weren't that different from what we see in some democratic countries today," says Gary Feinman, the MacArthur curator of anthropology at Chicago's Field Museum and one of the authors of a new study in Frontiers in Political Science. "The states that had good governance, although they may have been able to sustain themselves slightly longer than autocratic-run ones, tended to collapse more thoroughly, more severely."

"We noted the potential for failure caused by an internal factor that might have been manageable if properly anticipated," says Richard Blanton, a professor emeritus of anthropology at Purdue University and the study's lead author. "We refer to an inexplicable failure of the principal leadership to uphold values and norms that had long guided the actions of previous leaders, followed by a subsequent loss of citizen confidence in the leadership and government and collapse."

In their study, Blanton, Feinman, and their colleagues took an in-depth look at the governments of four societies: the Roman Empire, China's Ming Dynasty, India's Mughal Empire, and the Venetian Republic. These societies flourished hundreds (or in ancient Rome's case, thousands) of years ago, and they had comparatively more equitable distributions of power and wealth than many of the other cases examined, although they looked different from what we consider "good governments" today as they did not have popular elections.

"There were basically no electoral democracies before modern times, so if you want to compare good governance in the present with good governance in the past, you can't really measure it by the role of elections, so important in contemporary democracies. You have to come up with some other yardsticks, and the core features of the good governance concept serve as a suitable measure of that," says Feinman. "They didn't have elections, but they had other checks and balances on the concentration of personal power and wealth by a few individuals. They all had means to enhance social well-being, provision goods and services beyond just a narrow few, and means for commoners to express their voices."

In societies that meet the academic definition of "good governance," the government meets the needs of the people, in large part because the government depends on those people for the taxes and resources that keep the state afloat. "These systems depended heavily on the local population for a good chunk of their resources. Even if you don't have elections, the government has to be at least somewhat responsive to the local population, because that's what funds the government," explains Feinman. "There are often checks on both the power and the economic selfishness of leaders, so they can't hoard all the wealth." 

Societies with good governance tend to last a bit longer than autocratic governments that keep power concentrated to one person or small group. But the flip side of that coin is that when a "good" government collapses, things tend to be harder for the citizens, because they'd come to rely on the infrastructure of that government in their day-to-day life. "With good governance, you have infrastructures for communication and bureaucracies to collect taxes, sustain services, and distribute public goods. You have an economy that jointly sustains the people and funds the government," says Feinman. "And so social networks and institutions become highly connected, economically, socially, and politically. Whereas if an autocratic regime collapses, you might see a different leader or you might see a different capital, but it doesn't permeate all the way down into people's lives, as such rulers generally monopolize resources and fund their regimes in ways less dependent on local production or broad-based taxation."

The researchers also examined a common factor in the collapse of societies with good governance: leaders who abandoned the society's founding principles and ignored their roles as moral guides for their people. "In a good governance society, a moral leader is one who upholds the core principles and ethos and creeds and values of the overall society," says Feinman. "Most societies have some kind of social contract, whether that's written out or not, and if you have a leader who breaks those principles, then people lose trust, diminish their willingness to pay taxes, move away, or take other steps that undercut the fiscal health of the polity."

This pattern of amoral leaders destabilizing their societies goes way back--the paper uses the Roman Empire as an example. The Roman emperor Commodus inherited a state with economic and military instability, and he didn't rise to the occasion; instead, he was more interested in performing as a gladiator and identifying himself with Hercules. He was eventually assassinated, and the empire descended into a period of crisis and corruption. These patterns can be seen today, as corrupt or inept leaders threaten the core principles and, hence, the stability of the places they govern. Mounting inequality, concentration of political power, evasion of taxation, hollowing out of bureaucratic institutions, diminishment of infrastructure, and declining public services are all evidenced in democratic nations today.

"What I see around me feels like what I've observed in studying the deep histories of other world regions, and now I'm living it in my own life," says Feinman. "It's sort of like Groundhog Day for archaeologists and historians."

"Our findings provide insights that should be of value in the present, most notably that societies, even ones that are well governed, prosperous, and highly regarded by most citizens, are fragile human constructs that can fail," says Blanton. "In the cases we address, calamity could very likely have been avoided, yet, citizens and state-builders too willingly assumed that their leadership will feel an obligation to do as expected for the benefit of society. Given the failure to anticipate, the kinds of institutional guardrails required to minimize the consequences of moral failure were inadequate."

But, notes Feinman, learning about what led to societies collapsing in the past can help us make better choices now: "History has a chance to tell us something. That doesn't mean it's going to repeat exactly, but it tends to rhyme. And so that means there are lessons in these situations."

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