Friday, March 5, 2021

Apollo Rock Samples Capture Key Moments in the Moon’s Early History, Study Finds

A new analysis of samples brought back from the Moon to helps clear up questions about the isotopic composition of Moon’s interior.

 Volcanic rock samples collected during NASA’s Apollo missions bear the isotopic signature of key events in the early evolution of the Moon, a new analysis found. Those events include the formation of the Moon’s iron core, as well as the crystallization of the lunar magma ocean — the sea of molten rock thought to have covered the Moon for around 100 million years after it formed.

Apollo 15 Lunar Module Pilot James Irwin salutes the U.S. flag. Astronaut James B. Irwin, lunar module pilot, gives a military salute while standing beside the deployed U.S. flag during the Apollo 15 lunar surface extravehicular activity (EVA) at the Hadley-Apennine landing site. The flag was deployed toward the end of EVA-2. The Lunar Module (LM) "Falcon" is in the center. On the right is the Lunar Roving Vehicle (LRV). This view is looking almost due south. Hadley Delta in the background rises approximately 4,000 meters (about 13,124 feet) above the plain. The base of the mountain is approximately 5 kilometers (about 3 statute miles) away. This photograph was taken by Astronaut David R. Scott, Apollo 15 commander

Credit: NASA



The analysis, published in the journal Science Advances, used a technique called secondary ion mass spectrometry (SIMS) to study volcanic glasses returned from the Apollo 15 and 17 missions, which are thought to represent some of the most primitive volcanic material on the Moon. The study looked specifically at sulfur isotope composition, which can reveal details about the chemical evolution of lavas from generation, transport and eruption.

“For many years it appeared as though the lunar basaltic rock samples analyzed had a very limited variation in sulfur isotope ratios,” said Alberto Saal, a geology professor at Brown University and study co-author. “That would suggest that the interior of the Moon has a basically homogeneous sulfur isotopic composition. But using modern in situ analytical techniques, we show that the isotope ratios of the volcanic glasses actually have a fairly wide range, and those variations can be explained by events early in lunar history.”

The sulfur signature of interest is the ratio of the “heavy” sulfur-34 isotope to the lighter sulfur-32. Initial studies of lunar volcanic samples found that they uniformly leaned toward the heavier sulfur-34. The nearly homogeneous sulfur isotope ratio was in contrast with large variations in other elements and isotopes detected in the lunar samples.

This new study looked at 67 individual volcanic glass samples and their melt inclusions — tiny blobs of molten lava trapped within crystals inside the glass. Melt inclusions capture the lava before sulfur and other volatile elements are released as gas during eruption — a process called degassing. As such, they offer a pristine picture of what the original source lava was like. Using the SIMS at the Carnegie Institution for Science, Saal with his colleague, the late Carnegie scientist Eric Hauri, were able to measure the sulfur isotopes in these pristine melt inclusions and glasses, and use those results to calibrate a model of the degassing process for all the samples.

“Once we know the degassing, then we can estimate back the original sulfur isotope composition of the sources that produced these lavas,” Saal said.

Those calculations revealed that the lavas had been derived from different reservoirs within the interior of the Moon with a wide range of sulfur isotope ratios. The researchers then showed that the range of values detected in the samples could be explained by events in the Moon’s early history.

The lighter isotope ratio in some of the volcanic glasses, for example, is consistent with the segregation of the iron core from the early molten Moon. When an iron core separates from other material in a planetary body, it takes a bit of sulfur with it. The sulfur that’s taken tends to be the heavier sulfur-34 isotope, leaving the remaining magma enriched in the lighter sulfur-32.

“The values we see in some of the volcanic glasses are fully consistent with models of the core segregation process,” Saal said.

The heavier isotope values can be explained by the further cooling and crystallization of the early molten Moon. The crystallization process removes sulfur from the magma pool, producing solid reservoirs with heavier sulfur-34. That process is the likely source of the heavier isotope values found in some of the volcanic glasses and basaltic rocks returned from the Moon.

“Our results suggest that these samples record these critical events in lunar history,” Saal said. “As we keep looking at these samples with newer and better techniques, we keep learning new things.”

More work needs to be done — and more samples need to be analyzed — to fully understand the sulfur isotopic composition of the Moon, Saal says. But these new results help to clarify long-standing questions about the composition of the Moon’s interior, and they bring scientists one step closer to understanding the formation and early history of the Moon.

The research was funded by NASA’s Solar System Workings program (80NSSC20K0461).







Contacts and sources:
Kevin Stacey
Brown University


Publication: Large sulfur isotope fractionation in lunar volcanic glasses reveals the magmatic differentiation and degassing of the Moon.
Alberto E. Saal, Erik H. Hauri. Science Advances, 2021; 7 (9): eabe4641 DOI: 10.1126/sciadv.abe4641






Neanderthals Could Perceive and Produce Human Speech

3D model and virtual reconstruction of the ear in a modern human (left) and the Amud 1 Neandertal (right)


Image Credit: Mercedes Conde-Valverde.

Neanderthals — the closest ancestor to modern humans — possessed the ability to perceive and produce human speech, according to a new study published by an international multidisciplinary team of researchers including Binghamton University Associate Professor of Anthropology Rolf Quam and graduate student Alex Velez.

“This is one of the most important studies I have been involved in during my career,” said Quam. “The results are solid and clearly show the Neanderthals had the capacity to perceive and produce human speech. This is one of the very few current, ongoing research lines relying on fossil evidence to study the evolution of language, a notoriously tricky subject in anthropology.”

The evolution of language, and the linguistic capacities in Neanderthals in particular, is a long-standing question in human evolution.

“For decades, one of the central questions in human evolutionary studies has been whether the human form of communication, spoken language, was also present in any other species of human ancestor, especially the Neanderthals,” said coauthor Juan Luis Arsuaga, professor of paleontology at the Universidad Complutense de Madrid and co-director of excavations and research at the Atapuerca archaeological sites in northern Spain. The latest study has reconstructed how Neanderthals heard to draw some inferences about how they may have communicated.

The study relied on high resolution CT scans to create virtual 3D models of the ear structures in Homo sapiens and Neanderthals as well as earlier fossils from the site of Atapuerca that represent ancestors of the Neanderthals. Data collected on the 3D models were entered into a software-based model, developed in the field of auditory bioengineering, to estimate the hearing abilities up to 5 kHz, which encompasses most of the frequency range of modern human speech sounds. Compared with the Atapuerca fossils, the Neanderthals showed slightly better hearing between 4-5 kHz, resembling modern humans more closely.

In addition, the researchers were able to calculate the frequency range of maximum sensitivity, technically known as the occupied bandwidth, in each species. The occupied bandwidth is related to the communication system, such that a wider bandwidth allows for a larger number of easily distinguishable acoustic signals to be used in the oral communication of a species. This, in turn, improves the efficiency of communication, the ability to deliver a clear message in the shortest amount of time. The Neanderthals show a wider bandwidth compared with their ancestors from Atapuerca, more closely resembling modern humans in this feature.

“This really is the key,” said Mercedes Conde-Valverde, professor at the Universidad de Alcalá in Spain and lead author of the study. “The presence of similar hearing abilities, particularly the bandwidth, demonstrates that the Neanderthals possessed a communication system that was as complex and efficient as modern human speech.”

“One of the other interesting results from the study was the suggestion that Neanderthal speech likely included an increased use of consonants,” said Quam. “Most previous studies of Neanderthal speech capacities focused on their ability to produce the main vowels in English spoken language. However, we feel this emphasis is misplaced, since the use of consonants is a way to include more information in the vocal signal and it also separates human speech and language from the communication patterns in nearly all other primates. The fact that our study picked up on this is a really interesting aspect of the research and is a novel suggestion regarding the linguistic capacities in our fossil ancestors.”

Thus, Neanderthals had a similar capacity to us to produce the sounds of human speech, and their ear was “tuned” to perceive these frequencies. This change in the auditory capacities in Neanderthals, compared with their ancestors from Atapuerca, parallels archaeological evidence for increasingly complex behavioral patterns, including changes in stone tool technology, domestication of fire and possible symbolic practices. Along these lines, the study provides strong evidence in favor of the coevolution of increasingly complex behaviors and increasing efficiency in vocal communication throughout the course of human evolution.

The team behind the new study has been developing this research line for nearly two decades, and has ongoing collaborations to extend the analyses to additional fossil species. For the moment, however, the new results are exciting.

“These results are particularly gratifying,” said Ignacio Martinez, a professor at Universidad de Alcalá in Spain. “We believe, after more than a century of research into this question, that we have provided a conclusive answer to the question of Neanderthal speech capacities.”

The study, “Neandertals and modern humans had similar auditory and speech capacities,” was published in Nature Ecology and Evolution.



Contacts and sources:
Binghamton University


Publication: Neanderthals and Homo sapiens had similar auditory and speech capacities.
Mercedes Conde-Valverde, Ignacio Martínez, Rolf M. Quam, Manuel Rosa, Alex D. Velez, Carlos Lorenzo, Pilar Jarabo, José María Bermúdez de Castro, Eudald Carbonell, Juan Luis Arsuaga. Nature Ecology & Evolution, 2021; DOI: 10.1038/s41559-021-01391-6






Origin of Life: The Chicken-and-the-Egg Problem

 
A LMU team has shown that slight alterations in transfer-RNA molecules (tRNAs) allow them to self-assemble into a functional unit that can replicate information exponentially. tRNAs are key elements in the evolution of early life-forms.

A replicator made of tRNA-like sequences 

Credit:  © Kudella / LMU

Life as we know it is based on a complex network of interactions, which take place at microscopic scales in biological cells, and involve thousands of distinct molecular species. In our bodies, one fundamental process is repeated countless times every day. In an operation known as replication, proteins duplicate the genetic information encoded in the DNA molecules stored in the cell nucleus – before distributing them equally to the two daughter cells during cell division. The information is then selectively copied (‘transcribed’) into what are called messenger RNA molecules (mRNAs), which direct the synthesis of the many different proteins required by the cell type concerned. 

A second type of RNA – transfer RNA (tRNA) – plays a central role in the ‘translation’ of mRNAs into proteins. Transfer RNAs act as intermediaries between mRNAs and proteins: they ensure that the amino-acid subunits of which each particular protein consists are put together in the sequence specified by the corresponding mRNA.

How could such a complex interplay between DNA replication and the translation of mRNAs into proteins have arisen when living systems first evolved on the early Earth? We have here a classical example of the chicken-and-the-egg problem: Proteins are required for transcription of the genetic information, but their synthesis itself depends on transcription.

LMU physicists led by Professor Dieter Braun have now demonstrated how this conundrum could have been resolved. They have shown that minor modifications in the structures of modern tRNA molecules permit them to autonomously interact to form a kind of replication module, which is capable of exponentially replicating information. This finding implies that tRNAs – the key intermediaries between transcription and translation in modern cells – could also have been the crucial link between replication and translation in the earliest living systems. It could therefore provide a neat solution to the question of which came first – genetic information or proteins?

Complex relationship

Strikingly, in terms of their sequences and overall structure, tRNAs are highly conserved in all three domains of life, i.e. the unicellular Archaea and Bacteria (which lack a cell nucleus) and the Eukaryota (organisms whose cells contain a true nucleus). This fact in itself suggests that tRNAs are among the most ancient molecules in the biosphere.

Like the later steps in the evolution of life, the evolution of replication and translation – and the complex relationship between them – was not the result of a sudden single step. It is better understood as the culmination of an evolutionary journey. “Fundamental phenomena such as self-replication, autocatalysis, self-organization and compartmentalization are likely to have played important roles in these developments,” says Dieter Braun. “And on a more general note, such physical and chemical processes are wholly dependent on the availability of environments that provide non-equilibrium conditions.”

In their experiments, Braun and his colleagues used a set of reciprocally complementary DNA strands modeled on the characteristic form of modern tRNAs. Each was made up of two ‘hairpins’ (so called because each strand could partially pair with itself and form an elongated loop structure), separated by an informational sequence in the middle. Eight such strands can interact via complementary base-pairing to form a complex. Depending on the pairing patterns dictated by the central informational regions, this complex was able to encode a 4-digit binary code.

It is therefore conceivable that such a replication mechanism could have taken place on a hydrothermal microsystem on the early Earth.PROF. DIETER BRAUN, SYSTEMS BIOPHYSICS, LMU

A step closer to the reconstruction of the origin of life

During the copying process, complementary strands (drawn from the pool of molecules) pair up with the informational segment of the template strands. In the course of time, the adjacent hairpins of these strands also pair up to form a stable backbone, and temperature oscillations continue to drive the amplification process. If the temperature is increased for a brief period, the template strands are separated from the newly formed replicate, and both can then serve as template strands in the next round of replication.

The team was able to show that the system is capable of exponential replication. This is an important finding, as it shows that the replication mechanism is particularly resistant to collapse owing to the accumulation of errors. The fact that the structure of the replicator complex itself resembles that of modern tRNAs suggests that early forms of tRNA could have participated in molecular replication processes, before tRNA molecules assumed their modern role in the translation of messenger RNA sequences into proteins.

 “This link between replication and translation in an early evolutionary scenario could provide a solution to the chicken-and-the-egg problem,” says Alexandra Kühnlein. It could also account for the characteristic form of proto-tRNAs, and elucidate the role of tRNAs before they were co-opted for use in translation.

Laboratory research on the origin of life and the emergence of Darwinian evolution at the level of chemical polymers also has implications for the future of biotechnology. “Our investigations of early forms of molecular replication and our discovery of a link between replication and translation brings us a step closer to the reconstruction of the origin of life,” Braun concludes.



Contacts and sources:
Ludwig-Maximilians-Universität München




Publication: tRNA sequences can assemble into a replicator.
Alexandra Kühnlein, Simon A Lanzmich, Dieter Braun. eLife, 2021; 10 DOI: 10.7554/eLife.63431




The Right “5-a-Day” Mix Is 2 Fruit and 3 Vegetable Servings for Longer Life

Studies representing nearly 2 million adults worldwide show that eating about five daily servings of fruits and vegetables, in which 2 are fruits and 3 are vegetables, is likely the optimal amount for a longer life, according to new research published today in the American Heart Association’s flagship journal Circulation.

Diets rich in fruits and vegetables help reduce risk for numerous chronic health conditions that are leading causes of death, including cardiovascular disease and cancer. Yet, only about one in 10 adults eat enough fruits or vegetables, according to the U.S. Centers for Disease Control and Prevention.

Credit: American Heart Association

“While groups like the American Heart Association recommend four to five servings each of fruits and vegetables daily, consumers likely get inconsistent messages about what defines optimal daily intake of fruits and vegetables such as the recommended amount, and which foods to include and avoid,” said lead study author Dong D. Wang, M.D., Sc.D., an epidemiologist, nutritionist and a member of the medical faculty at Harvard Medical School and Brigham and Women’s Hospital in Boston.

Wang and colleagues analyzed data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, two studies including more than 100,000 adults who were followed for up to 30 years. Both datasets included detailed dietary information repeatedly collected every two to four years. For this analysis, researchers also pooled data on fruit and vegetable intake and death from 26 studies that included about 1.9 million participants from 29 countries and territories in North and South America, Europe, Asia, Africa and Australia.

Analysis of all studies, with a composite of more than 2 million participants, revealed:


Intake of about five servings of fruits and vegetables daily was associated with the lowest risk of death. Eating more than five servings was not associated with additional benefits

Eating about two servings daily of fruits and three servings daily of vegetables was associated with the greatest longevity.

Compared to those who consumed two servings of fruit and vegetables per day, participants who consumed five servings a day of fruits and vegetable had a 13% lower risk of death from all causes; a 12% lower risk of death from cardiovascular disease, including heart disease and stroke; a 10% lower risk of death from cancer; and a 35% lower risk of death from respiratory disease, such as chronic obstructive pulmonary disease (COPD).

Not all foods that one might consider to be fruits and vegetables offered the same benefits. For example: Starchy vegetables, such as peas and corn, fruit juices and potatoes were not associated with reduced risk of death from all causes or specific chronic diseases.

On the other hand, green leafy vegetables, including spinach, lettuce and kale, and fruit and vegetables rich in beta carotene and vitamin C, such as citrus fruits, berries and carrots, showed benefits.

“Our analysis in the two cohorts of U.S. men and women yielded results similar to those from 26 cohorts around the world, which supports the biological plausibility of our findings and suggests these findings can be applied to broader populations,” Wang said.

Wang said this study identifies an optimal intake level of fruits and vegetables and supports the evidence-based, succinct public health message of ‘5-a-day,’ meaning people should ideally consume five servings of fruit and vegetable each day. “This amount likely offers the most benefit in terms of prevention of major chronic disease and is a relatively achievable intake for the general public,” he said. “We also found that not all fruits and vegetables offer the same degree of benefit, even though current dietary recommendations generally treat all types of fruits and vegetables, including starchy vegetables, fruit juices and potatoes, the same.”

A limitation of the research is that it is observational, showing an association between fruit and vegetable consumption and risk of death; it does not confer a direct cause-and-effect relationship.

“The American Heart Association recommends filling at least half your plate with fruits and vegetables at each meal,” said Anne Thorndike, M.D., M.P.H., chair of the American Heart Association’s nutrition committee and an associate professor of medicine at Harvard Medical School in Boston. “This research provides strong evidence for the lifelong benefits of eating fruits and vegetables and suggests a goal amount to consume daily for ideal health. Fruits and vegetables are naturally packaged sources of nutrients that can be included in most meals and snacks, and they are essential for keeping our hearts and bodies healthy.”

Co-authors are Yanping Li, Ph.D.; Shilpa N. Bhupathiraju, Ph.D.; Bernard A. Rosner, Ph.D.; Qi Sun, M.D., Sc.D.; Edward L. Giovannucci; Eric B. Rimm, Sc.D.; JoAnn E. Manson, M.D., M.P.H., Dr.P.H., FAHA; Walter C. Willett, M.D., Dr.P.H.; Meir J. Stampfer, M.D., Dr.P.H.; and Frank B. Hu, M.D., Ph.D.

The study was funded by the National Institutes of Health, the American Heart Association and the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.




Contacts and sources:
American Heart Association




Publication: Fruit and Vegetable Intake and Mortality: Results From 2 Prospective Cohort Studies of US Men and Women and a Meta-Analysis of 26 Cohort Studies.
Dong D. Wang, Yanping Li, Shilpa N. Bhupathiraju, Bernard A. Rosner, Qi Sun, Edward L. Giovannucci, Eric B. Rimm, JoAnn E. Manson, Walter C. Willett, Meir J. Stampfer, Frank B. Hu. Circulation, 2021; DOI: 10.1161/CIRCULATIONAHA.120.048996



'Space Hurricane' in Earth's Discovered in Earth's Upper Atmosphere

The first observations of a space hurricane have been revealed in Earth’s upper atmosphere, confirming their existence and shedding new light on the relationship between planets and space.

The unprecedented observations, made by satellites in August 2014, were only uncovered during retrospective analysis by scientists at the University of Reading, as part of a team led by Shandong University in China, that confirmed the hurricane and offered clues about its formation.


Credit: University of Reading

This analysis has now allowed a 3D image to be created of the 1,000km-wide swirling mass of plasma several hundred kilometres above the North Pole, raining electrons instead of water, and in many ways resembling the hurricanes we are familiar with in the Earth’s lower atmosphere.

Professor Mike Lockwood, space scientist at the University of Reading, said: “Until now, it was uncertain that space plasma hurricanes even existed, so to prove this with such a striking observation is incredible”.

“Tropical storms are associated with huge amounts of energy, and these space hurricanes must be created by unusually large and rapid transfer of solar wind energy and charged particles into the Earth’s upper atmosphere.

“Plasma and magnetic fields in the atmosphere of planets exist throughout the universe, so the findings suggest space hurricanes should be a widespread phenomena.”

Hurricanes occur in Earth’s lower atmosphere over warm bodies of water. When warm, moist air rises, it creates an area of low pressure near the surface that sucks in the surrounding air, causing extremely strong winds and creating clouds that lead to heavy rain.

Hurricanes have also been observed in the lower atmospheres of Mars, Jupiter and Saturn, while enormous solar tornadoes have been seen in the atmosphere of the Sun. However, the existence of space hurricanes in the upper atmosphere of planets has not been detected before.

The space hurricane analysed by the team in Earth’s ionosphere was spinning in an anticlockwise direction, had multiple spiral arms, and lasted almost eight hours before gradually breaking down.

The team of scientists from China, the USA, Norway and the UK used observations made by four DMSP (Defense Meteorological Satellite Program) satellites and a 3D magnetosphere modelling to produce the image. Their findings were published in Nature Communications.

The analysis involved checking data from the satellites, radars and other sources for consistency, and to build up a full picture of what had happened and ensure that the mechanisms involved were understood.

The fact the hurricane occurred during a period of low geomagnetic activity suggests they could be more relatively common within our solar system and beyond. This highlights the importance of improved monitoring of space weather, which can disrupt GPS systems.

 


Contacts and sources:
University of Reading
 


Publication: A space hurricane over the Earth’s polar ionosphere
Qing-He Zhang, Yong-Liang Zhang, Chi Wang, Kjellmar Oksavik, Larry R. Lyons, Michael Lockwood, Hui-Gen Yang, Bin-Bin Tang, Jøran Idar Moen, Zan-Yang Xing, Yu-Zhang Ma, Xiang-Yu Wang, Ya-Fei Ning, Li-Dong Xia. . Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-21459-y




An AI Gen­er­ates Per­son­ally At­tract­ive Im­ages by Read­ing Subject's Brain


Researchers have succeeded in making an AI understand our subjective notions of what makes faces attractive. The device demonstrated this knowledge by its ability to create new portraits on its own that were tailored to be found personally attractive to individuals. The results can be utilised, for example, in modelling preferences and decision-making as well as potentially identifying unconscious attitudes.

A computer created facial images that appealed to individual preferences.

Credit: COGNITIVE COMPUTING -TUTKIMUSRYHMÄ

Researchers at the University of Helsinki and University of Copenhagen investigated whether a computer would be able to identify the facial features we consider attractive and, based on this, create new images matching our criteria. The researchers used artificial intelligence to interpret brain signals and combined the resulting brain-computer interface with a generative model of artificial faces. This enabled the computer to create facial images that appealed to individual preferences.

“In our previous studies, we designed models that could identify and control simple portrait features, such as hair colour and emotion. However, people largely agree on who is blond and who smiles. Attractiveness is a more challenging subject of study, as it is associated with cultural and psychological factors that likely play unconscious roles in our individual preferences. Indeed, we often find it very hard to explain what it is exactly that makes something, or someone, beautiful: Beauty is in the eye of the beholder,” says Senior Researcher and Docent Michiel Spapé from the Department of Psychology and Logopedics, University of Helsinki.

The study, which combines computer science and psychology, was published in February in the IEEE Transactions in Affective Computing journal.

Pref­er­en­ces ex­posed by the brain

Initially, the researchers gave a generative adversarial neural network (GAN) the task of creating hundreds of artificial portraits. The images were shown, one at a time, to 30 volunteers who were asked to pay attention to faces they found attractive while their brain responses were recorded via electroencephalography (EEG).

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Credit: University of Helsinki

“It worked a bit like the dating app Tinder: the participants ‘swiped right’ when coming across an attractive face. Here, however, they did not have to do anything but look at the images. We measured their immediate brain response to the images,” Spapé explains.

The researchers analysed the EEG data with machine learning techniques, connecting individual EEG data through a brain-computer interface to a generative neural network.

“A brain-computer interface such as this is able to interpret users' opinions on the attractiveness of a range of images. By interpreting their views, the AI model interpreting brain responses and the generative neural network modelling the face images can together produce an entirely new face image by combining what a particular person finds attractive,” says Academy Research Fellow and Associate Professor Tuukka Ruotsalo, who heads the project.

To test the validity of their modelling, the researchers generated new portraits for each participant, predicting they would find them personally attractive. Testing them in a double-blind procedure against matched controls, they found that the new images matched the preferences of the subjects with an accuracy of over 80%.

“The study demonstrates that we are capable of generating images that match personal preference by connecting an artificial neural network to brain responses. Succeeding in assessing attractiveness is especially significant, as this is such a poignant, psychological property of the stimuli. Computer vision has thus far been very successful at categorising images based on objective patterns. By bringing in brain responses to the mix, we show it is possible to detect and generate images based on psychological properties, like personal taste,” Spapé explains.

Po­ten­tial for ex­pos­ing un­con­scious at­ti­tudes

Ultimately, the study may benefit society by advancing the capacity for computers to learn and increasingly understand subjective preferences, through interaction between AI solutions and brain-computer interfaces.

“If this is possible in something that is as personal and subjective as attractiveness, we may also be able to look into other cognitive functions such as perception and decision-making. Potentially, we might gear the device towards identifying stereotypes or implicit bias and better understand individual differences,” says Spapé.
  

Read more:
Cognitive computing research group
A computer predicts your thoughts, creating images based on them
Brainsourcing automatically identifies human preferences
The brain uses minimum effort to look for key information in text



Contacts and sources:
Aino Pekkarinen
University of Helsinki

Michiel Spapé (contacts in English)
Senior researcher, Department of Psychology and Logopedics, University of Helsinki
 

Tuukka Ruotsalo
Academy research fellow, Department of Computer Science, University of Helsinki & Finnish Center for Artificial Intelligence FCAI
Associate professor, Department of Computer Science, University of Copenhagen


Publication:"Brain-computer interface for generating personally attractive images,"
Michiel Spape, Keith Davis, Lauri Kangassalo, Niklas Ravaja, Zania Sovijarvi-Spape, Tuukka Ruotsalo. IEEE Transactions on Affective Computing, 2021; 1 DOI: 10.1109/TAFFC.2021.3059043






 

The (Robotic) Doctor Will See You Now

A majority of patients interacting with a health care provider via a video screen mounted on a robot said it was similar to an in-person interaction with a health care worker. A study finds patients are receptive to interacting with robots designed to evaluate symptoms in a contact-free way.


 Credits: MIT News, with images from iStockphoto


In the era of social distancing, using robots for some health care interactions is a promising way to reduce in-person contact between health care workers and sick patients. However, a key question that needs to be answered is how patients will react to a robot entering the exam room.

Researchers from MIT and Brigham and Women’s Hospital recently set out to answer that question. In a study performed in the emergency department at Brigham and Women’s, the team found that a large majority of patients reported that interacting with a health care provider via a video screen mounted on a robot was similar to an in-person interaction with a health care worker.

“We’re actively working on robots that can help provide care to maximize the safety of both the patient and the health care workforce. The results of this study give us some confidence that people are ready and willing to engage with us on those fronts,” says Giovanni Traverso, an MIT assistant professor of mechanical engineering, a gastroenterologist at Brigham and Women’s Hospital, and the senior author of the study.

In a larger online survey conducted nationwide, the researchers also found that a majority of respondents were open to having robots not only assist with patient triage but also perform minor procedures such as taking a nose swab.

Peter Chai, an assistant professor of emergency medicine at Brigham and Women’s Hospital and a research affiliate in Traverso’s lab, is the lead author of the study, which appears today in JAMA Network Open.


Triage by robot

After the Covid-19 pandemic began early last year, Traverso and his colleagues turned their attention toward new strategies to minimize interactions between potentially sick patients and health care workers. To that end, they worked with Boston Dynamics to create a mobile robot that could interact with patients as they waited in the emergency department. The robots were equipped with sensors that allow them to measure vital signs, including skin temperature, breathing rate, pulse rate, and blood oxygen saturation. The robots also carried an iPad that allowed for remote video communication with a health care provider.

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This kind of robot could reduce health care workers’ risk of exposure to Covid-19 and help to conserve the personal protective equipment that is needed for each interaction. However, the question still remained whether patients would be receptive to this type of interaction.

“Often as engineers, we think about different solutions, but sometimes they may not be adopted because people are not fully accepting of them,” Traverso says. “So, in this study we were trying to tease that out and understand if the population is receptive to a solution like this one.”

The researchers first conducted a nationwide survey of about 1,000 people, working with a market research company called YouGov. They asked questions regarding the acceptability of robots in health care, including whether people would be comfortable with robots performing not only triage but also other tasks such as performing nasal swabs, inserting a catheter, or turning a patient over in bed. On average, the respondents stated that they were open to these types of interactions.

The researchers then tested one of their robots in the emergency department at Brigham and Women’s Hospital last spring, when Covid-19 cases were surging in Massachusetts. Fifty-one patients were approached in the waiting room or a triage tent and asked if they would be willing to participate in the study, and 41 agreed. These patients were interviewed about their symptoms via video connection, using an iPad carried by a quadruped, dog-like robot developed by Boston Dynamics. More than 90 percent of the participants reported that they were satisfied with the robotic system.

“For the purposes of gathering quick triage information, the patients found the experience to be similar to what they would have experienced talking to a person,” Chai says.

Robotic assistants

The numbers from the study suggest that it could be worthwhile to try to develop robots that can perform procedures that currently require a lot of human effort, such as turning a patient over in bed, the researchers say. Turning Covid-19 patients onto their stomachs, also known as “proning,” has been shown to boost their blood oxygen levels and make breathing easier. Currently the process requires several people to perform. Administering Covid-19 tests is another task that requires a lot of time and effort from health care workers, who could be deployed for other tasks if robots could help perform swabs.

“Surprisingly, people were pretty accepting of the idea of having a robot do a nasal swab, which suggests that potential engineering efforts could go into thinking about building some of these systems,” Chai says.

The MIT team is continuing to develop sensors that can obtain vital sign data from patients remotely, and they are working on integrating these systems into smaller robots that could operate in a variety of environments, such as field hospitals or ambulances.

Other authors of the paper include Farah Dadabhoy, Hen-wei Huang, Jacqueline Chu, Annie Feng, Hien Le, Joy Collins, Marco da Silva, Marc Raibert, Chin Hur, and Edward Boyer. The research was funded by the National Institutes of Health, the Hans and Mavis Lopater Psychosocial Foundation, e-ink corporation, the Karl Van Tassel (1925) Career Development Professorship, MIT’s Department of Mechanical Engineering, and the Brigham and Women’s Hospital Division of Gastroenterology.


Contacts and sources:
Anne Trafton
Massachusetts Institute of Technology




Publication: Assessment of the Acceptability and Feasibility of Using Mobile Robotic Systems for Patient Evaluation.
Peter R. Chai, Farah Z. Dadabhoy, Hen-Wei Huang, Jacqueline N. Chu, Annie Feng, Hien M. Le, Joy Collins, Marco da Silva, Marc Raibert, Chin Hur, Edward W. Boyer, Giovanni Traverso.JAMA Network Open, 2021; 4 (3): e210667 DOI: 10.1001/jamanetworkopen.2021.0667




 



Comet Catalina Suggests Comets Delivered Carbon to Rocky Planets

This illustration of a comet from the Oort Cloud as it passes through the inner solar system with dust and gas evaporating into its tail. SOFIA’s observations of Comet Catalina reveal that it’s carbon-rich, suggesting that comets delivered carbon to the terrestrial planets like Earth and Mars as they formed in the early solar system. 


Credit: NASA/SOFIA/Lynette Cook

In early 2016, an icy visitor from the edge of our solar system hurtled past Earth. It briefly became visible to stargazers as Comet Catalina before it slingshotted past the Sun to disappear forevermore out of the solar system.

Among the many observatories that captured a view of this comet, which appeared near the Big Dipper, was the Stratospheric Observatory for Infrared Astronomy (SOFIA), NASA’s telescope on an airplane. Using one of its unique infrared instruments, SOFIA was able to pick out a familiar fingerprint within the dusty glow of the comet’s tail—carbon.

Now this one-time visitor to our inner solar system is helping explain more about our own origins as it becomes apparent that comets like Catalina could have been an essential source of carbon on planets like Earth and Mars during the early formation of the solar system.

New results from SOFIA, a joint project of NASA and the German Aerospace Center, were published in the Planetary Science Journal.

“Carbon is key to learning about the origins of life,” said the paper’s lead author, Charles “Chick” Woodward, an astrophysicist and professor in the University of Minnesota Twin Cities Minnesota Institute of Astrophysics. “We’re still not sure if Earth could have trapped enough carbon on its own during its formation, so carbon-rich comets could have been an important source delivering this essential element that led to life as we know it.”

Frozen in Time

Originating from the Oort Cloud at the farthest reaches of our solar system, Comet Catalina and others of its type have such long orbits that they arrive on our celestial doorstep relatively unaltered. This makes them effectively frozen in time, offering researchers rare opportunities to learn about the early solar system from which they come.

SOFIA’s infrared observations were able to capture the composition of the dust and gas as it evaporated off the comet, forming its tail. The observations showed that Comet Catalina is carbon-rich, suggesting that it formed in the outer regions of the primordial solar system, which held a reservoir of carbon that could have been important for seeding life.

While carbon is a key ingredient of life, early Earth and other terrestrial planets of the inner solar system were so hot during their formation that elements like carbon were lost or depleted. While the cooler gas giants like Jupiter and Neptune could support carbon in the outer solar system, Jupiter’s jumbo size may have gravitationally blocked carbon from mixing back into the inner solar system.

Primordial Mixing

So how did the inner rocky planets evolve into the carbon-rich worlds that they are today?

Researchers think that a slight change in Jupiter’s orbit allowed small, early precursors of comets to mix carbon from the outer regions into the inner regions, where it was incorporated into planets like Earth and Mars.

Comet Catalina’s carbon-rich composition helps explain how planets that formed in the hot, carbon-poor regions of the early solar system evolved into planets with the life-supporting element.

“All terrestrial worlds are subject to impacts by comets and other small bodies, which carry carbon and other elements,” Woodward said. “We are getting closer to understanding exactly how these impacts on early planets may have catalyzed life.”

Observations of additional new comets are needed to learn if there are many other carbon-rich comets in the Oort Cloud, which would further support that comets delivered carbon and other life-supporting elements to the terrestrial planets. As the world’s largest airborne observatory, SOFIA’s mobility allows it to quickly observe newly discovered comets as they make a pass through the solar system.

SOFIA is a joint project of NASA and the German Aerospace Center. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.



Contacts and sources:
University of Minnesota




Publication: The Coma Dust of Comet C/2013 US10 (Catalina): A Window into Carbon in the Solar System.
Charles E. Woodward, Diane H. Wooden, David E. Harker, Michael S. P. Kelley, Ray W. Russell, Daryl L. Kim. The Planetary Science Journal, 2021; 2 (1): 25 DOI: 10.3847/PSJ/abca3e




Monday, March 1, 2021

Supermassive Black Holes Could Form from Dark Matter, Study Suggests



Artist’s impression of a spiral galaxy embedded in a larger distribution of invisible dark matter, known as a dark matter halo (coloured in blue). Studies looking at the formation of dark matter haloes have suggested that each halo could harbour a very dense nucleus of dark matter, which may potentially mimic the effects of a central black hole, or eventually collapse to form one.
Credit: ESO / L. Calçada

A new theoretical study has proposed a novel mechanism for the creation of supermassive black holes from dark matter. The international team find that rather than the conventional formation scenarios involving ‘normal’ matter, supermassive black holes could instead form directly from dark matter in high density regions in the centres of galaxies. The result has key implications for cosmology in the early Universe, and is published in Monthly Notices of the Royal Astronomical Society.

Exactly how supermassive black holes initially formed is one of the biggest problems in the study of galaxy evolution today. Supermassive black holes have been observed as early as 800 million years after the Big Bang, and how they could grow so quickly remains unexplained.

Standard formation models involve normal baryonic matter – the atoms and elements that that make up stars, planets, and all visible objects – collapsing under gravity to form black holes, which then grow over time. However the new work investigates the potential existence of stable galactic cores made of dark matter, and surrounded by a diluted dark matter halo, finding that the centres of these structures could become so concentrated that they could also collapse into supermassive black holes once a critical threshold is reached.

According to the model this could have happened much more quickly than other proposed formation mechanisms, and would have allowed supermassive black holes in the early Universe to form before the galaxies they inhabit, contrary to current understanding.

Carlos R. Argüelles, the researcher at Universidad Nacional de La Plata and ICRANet who led the investigation comments: “This new formation scenario may offer a natural explanation for how supermassive black holes formed in the early Universe, without requiring prior star formation or needing to invoke seed black holes with unrealistic accretion rates.”

Another intriguing consequence of the new model is that the critical mass for collapse into a black hole might not be reached for smaller dark matter halos, for example those surrounding some dwarf galaxies. The authors suggest that this then might leave smaller dwarf galaxies with a central dark matter nucleus rather than the expected black hole. Such a dark matter core could still mimic the gravitational signatures of a conventional central black hole, whilst the dark matter outer halo could also explain the observed galaxy rotation curves.

“This model shows how dark matter haloes could harbour dense concentrations at their centres, which may play a crucial role in helping to understand the formation of supermassive black holes,” added Carlos.

“Here we’ve proven for the first time that such core–halo dark matter distributions can indeed form in a cosmological framework, and remain stable for the lifetime of the Universe.”

The authors hope that further studies will shed more light on supermassive black hole formation in the very earliest days of our Universe, as well as investigating whether the centres of non-active galaxies, including our own Milky Way, may play host to these dense dark matter cores.

 

Contacts and sources:
Dr. Robert Massey
Royal Astronomical Society

Dr Carlos R. Argüelles
Facultad de Ciencias Astronómicas y Geofísicas
Universidad Nacional de La Plata

Publication: On the formation and stability of fermionic dark matter haloes in a cosmological framework.
Carlos R Argüelles, Manuel I Díaz, Andreas Krut, Rafael Yunis. Monthly Notices of the Royal Astronomical Society, 2021; 502 (3): 4227 DOI: 10.1093/mnras/staa3986





NCI Study: People with SARS-CoV-2 Antibodies May Have a Low Risk of Future Infection


People who have had evidence of a prior infection with SARS-CoV-2, the virus that causes COVID-19, appear to be well protected against being reinfected with the virus, at least for a few months, according to a newly published study from the National Cancer Institute (NCI). This finding may explain why reinfection appears to be relatively rare, and it could have important public health implications, including decisions about returning to physical workplaces, school attendance, the prioritization of vaccine distribution, and other activities.

An artist’s rendering of a SARS-CoV-2 virus particle (pink) with spike proteins (yellow) and SARS-CoV-2 antibodies (blue).

Credit: iStock

For the study, researchers at NCI, part of the National Institutes of Health, collaborated with two health care data analytics companies (HealthVerity and Aetion, Inc.) and five commercial laboratories. The findings were published on Feb. 24 in JAMA Internal Medicine.

“While cancer research and cancer care remain the primary focus of NCI’s work, we were eager to lend our expertise in serological sciences to help address the global COVID-19 pandemic, at the request of Congress,” said NCI Director Norman E. “Ned” Sharpless, M.D., who was one of the coauthors on the study. “We hope that these results, in combination with those of other studies, will inform future public health efforts and help in setting policy.”

“The data from this study suggest that people who have a positive result from a commercial antibody test appear to have substantial immunity to SARS-CoV-2, which means they may be at lower risk for future infection,” said Lynne Penberthy, M.D., M.P.H., associate director of NCI’s Surveillance Research Program, who led the study. “Additional research is needed to understand how long this protection lasts, who may have limited protection, and how patient characteristics, such as comorbid conditions, may impact protection. We are nevertheless encouraged by this early finding.”

Antibody tests—also known as serology tests—detect serum antibodies, which are immune system proteins made in response to a specific foreign substance or infectious agent, such as SARS-CoV-2.

This study was launched in an effort to better understand whether, and to what degree, detectable antibodies against SARS-CoV-2 protect people from reinfection with the virus. Working with HealthVerity and Aetion, NCI aggregated and analyzed patient information collected from multiple sources, including five commercial labs (including Quest Diagnostics and Labcorp), electronic medical records, and private insurers. This was done in a way that protects the privacy of an individual’s health information and is compliant with relevant patient privacy laws.

The researchers ultimately obtained antibody test results for more than 3 million people who had a SARS-CoV-2 antibody test between Jan. 1 and Aug. 23, 2020. This represented more than 50% of the commercial SARS-CoV-2 antibody tests conducted in the United States during that time. Nearly 12% of these tests were antibody positive; most of the remaining tests were negative, and less than 1% were inconclusive.

About 11% of the seropositive individuals and 9.5% of the seronegative individuals later received a nucleic acid amplification test (NAAT)—sometimes referred to as a PCR test—for SARS-CoV-2. The research team looked at what fraction of individuals in each group subsequently had a positive NAAT result, which may indicate a new infection. The study team reviewed NAAT results at several intervals: 0-30 days, 31-60 days, 61-90 days, and >90 days because some people who have recovered from a SARS-CoV-2 infection can still shed viral material (RNA) for up to three months (although they likely do not remain infectious during that entire period).

The team found that, during each interval, between 3% and 4% of the seronegative individuals had a positive NAAT test. But among those who had originally been seropositive, the NAAT test positivity rate declined over time. When the researchers looked at test results 90 or more days after the initial antibody test (when any coronavirus detected by NAAT is likely to reflect a new infection rather than continued virus shedding from the original infection), only about 0.3% of those who had been seropositive had a positive NAAT result—about one-tenth the rate in those who had been seronegative.

Although these results support the idea that having antibodies against SARS-CoV-2 is associated with protection from future infection, the authors note important limitations to this study. In particular, the findings come from a scientific interpretation of real-world data, which are subject to biases that may be better controlled for in a clinical trial. For example, it is not known why people who had tested antibody positive went on to have a PCR test. In addition, the duration of protection is unknown; studies with longer follow-up time are needed to determine if protection wanes over time.

To continue to comprehensively address this important research question, NCI is supporting clinical studies that monitor infection rates in large populations of people whose antibody status is known. These are known as “seroprotection” studies. NCI is also sponsoring ongoing studies using real-world data to assess the longer-term effect of antibody positivity on subsequent infection rates.

This research is part of a $306 million effort that NCI has taken on at the request of Congress to develop, validate, improve, and implement serological testing and associated technologies applicable to COVID-19. Through this appropriation, NCI is working with the Department of Health and Human Services; the National Institute of Allergy and Infectious Diseases, another part of NIH; and other government agencies to apply its expertise and advanced research capabilities to respond to this pandemic, including efforts to rigorously characterize the performance of serology assays.


Contacts and sources:
NIH/National Cancer Institute

Publication: Association of SARS-CoV-2 Seropositive Antibody Test With Risk of Future Infection.
Raymond A. Harvey, Jeremy A. Rassen, Carly A. Kabelac, Wendy Turenne, Sandy Leonard, Reyna Klesh, William A. Meyer, Harvey W. Kaufman, Steve Anderson, Oren Cohen, Valentina I. Petkov, Kathy A. Cronin, Alison L. Van Dyke, Douglas R. Lowy, Norman E. Sharpless, Lynne T. Penberthy. JAMA Internal Medicine, 2021; DOI: 10.1001/jamainternmed.2021.0366





How Did Dogs Get to the Americas? An Ancient Dog Bone Fragment Holds Clues


The history of dogs has been intertwined, since ancient times, with that of the humans who domesticated them.

But how far back does that history go in the Americas, and which route did dogs use to enter this part of the world?

A new study led by the University at Buffalo provides insight into these questions. The research reports that a bone fragment found in Southeast Alaska belongs to a dog that lived in the region about 10,150 years ago. Scientists say the remains — a piece of a femur — represent the oldest confirmed remains of a domestic dog in the Americas.

This bone fragment, found in Southeast Alaska, belongs to a dog that lived about 10,150 years ago, a study concludes. Scientists say the remains, a piece of a femur, provide insight into the question of when dogs and humans first entered the Americas, and what route they took to get there.
Credit: Douglas Levere / University at Buffalo

DNA from the bone fragment holds clues about early canine history in this part of the world.

Researchers analyzed the dog’s mitochondrial genome, and concluded that the animal belonged to a lineage of dogs whose evolutionary history diverged from that of Siberian dogs as early as 16,700 years ago. The timing of that split coincides with a period when humans may have been migrating into North America along a coastal route that included Southeast Alaska.

The research was published on Feb. 24 in the Proceedings of the Royal Society B. Charlotte Lindqvist, an evolutionary biologist from UB, was senior author of the study, which included scientists from UB and the University of South Dakota. The findings add to a growing body of knowledge about the migration of dogs into the Americas.

“We now have genetic evidence from an ancient dog found along the Alaskan coast. Because dogs are a proxy for human occupation, our data help provide not only a timing but also a location for the entry of dogs and people into the Americas. Our study supports the theory that this migration occurred just as coastal glaciers retreated during the last Ice Age,” says Lindqvist, PhD, associate professor of biological sciences in the UB College of Arts and Sciences. “There have been multiple waves of dogs migrating into the Americas, but one question has been, when did the first dogs arrive? And did they follow an interior ice-free corridor between the massive ice sheets that covered the North American continent, or was their first migration along the coast?”

“The fossil record of ancient dogs in the Americas is incomplete, so any new remains that are found provide important clues,” says Flavio Augusto da Silva Coelho, a UB PhD student in biological sciences, and one of the paper’s first authors. "Before our study, the earliest ancient American dog bones that had their DNA sequenced were found in the U.S. Midwest."

A surprise finding from a large collection of bones
Credit: Bob Wilder / University at Buffalo
 
Lindqvist’s team did not set out to study dogs. The scientists came across the femur fragment while sequencing DNA from a collection of hundreds of bones excavated years before in Southeast Alaska by researchers including Timothy Heaton, PhD, professor of earth sciences at the University of South Dakota.

“This all started out with our interest in how Ice Age climatic changes impacted animals' survival and movements in this region,” Lindqvist says. “Southeast Alaska might have served as an ice-free stopping point of sorts, and now — with our dog — we think that early human migration through the region might be much more important than some previously suspected.”

The bone fragment, originally thought to come from a bear, was quite small, but when the DNA was studied, the team realized it was from a dog, Lindqvist says.
 
Flavio Augusto da Silva Coelho, a University at Buffalo PhD student in biological sciences, holds the ancient dog bone fragment that was found in Southeast Alaska.

 Credit: Douglas Levere / University at Buffalo

After this surprise discovery, the scientists compared the bone’s mitochondrial genome to those of other ancient and modern dogs. This analysis showed that the Southeast Alaskan dog shared a common ancestor about 16,000 years ago with American canines that lived before the arrival of European colonizers, Lindqvist says. (Mitochondrial DNA, inherited from the mother, represents a small fraction of an organism’s complete DNA, so sequencing a complete nuclear genome could provide further details if that material can be extracted.)

Of interest, carbon isotope analysis on the bone fragment indicates that the ancient Southeast Alaskan dog likely had a marine diet, which may have consisted of foods such as fish and scraps from seals and whales.

The research adds depth to the layered history of how dogs came to populate the Americas. As Lindqvist notes, canines did not arrive all at once. For example, some Arctic dogs arrived later from East Asia with the Thule culture, while Siberian huskies were imported to Alaska during the Gold Rush. Other dogs were brought to the Americas by European colonizers.

This bone fragment, found in Southeast Alaska, belongs to a dog that lived about 10,150 years ago, a study concludes. Scientists say the remains, a piece of a femur, provide insight into the question of when dogs and humans first entered the Americas, and what route they took to get there.

Credit: Douglas Levere / University at Buffalo


The new study sharpens the debate on dog and human migration into the Americas.

“Our early dog from Southeast Alaska supports the hypothesis that the first dog and human migration occurred through the Northwest Pacific coastal route instead of the central continental corridor, which is thought to have become viable only about 13,000 years ago,” Coelho notes.

The research was funded by the National Science Foundation. In addition to Lindqvist, Coelho and Heaton, authors of the new paper in Proceedings of the Royal Society B included Stephanie Gill and Crystal Tomlin.


Contacts and sources:
Charlotte Hsu
University at Buffalo




Publication: An early dog from southeast Alaska supports a coastal route for the first dog migration into the Americas.
Flavio Augusto da Silva Coelho, Stephanie Gill, Crystal M. Tomlin, Timothy H. Heaton, Charlotte Lindqvist. Proceedings of the Royal Society B: Biological Sciences, 2021; 288 (1945): 20203103 DOI: 10.1098/rspb.2020.3103


Spectacular ‘Honeycomb Heart’ Revealed in Iconic Crab Nebula Stellar Explosion

A unique ‘heart-shape’, with wisps of gas filaments showing an intricate honeycomb-like arrangement, has been discovered at the centre of the iconic supernova remnant, the Crab Nebula. Astronomers have mapped the void in unprecedented detail, creating a realistic three-dimensional reconstruction. The new work is published in Monthly Notices of the Royal Astronomical Society .

3D reconstruction of the Crab nebula remnant as seen from Earth (left), and from another point of view showing its heart-shaped morphology (right).

Credit: Thomas Martin, Danny Milisavljevic and Laurent Drissen

The Crab, formally known as Messier 1, exploded as a dramatic supernova in 1054 CE, and was observed over the subsequent months and years by ancient astronomers across the world. The resulting nebula - the remnant of this enormous explosion - has been studied by amateur and professional astronomers for centuries. However, despite this rich history of investigation, many questions remain about what type of star was originally there and how the original explosion took place.

Thomas Martin, the researcher at Université Laval who led the study, hopes to answer these questions using a new 3D reconstruction of the nebula. “Astronomers will now be able to move around and inside the Crab Nebula and study its filaments one by one,” said Martin.

The team used the powerful SITELLE imaging spectrometer on the Canada-Hawaii-France Telescope (CFHT) in Mauna Kea, Hawaii, to compare the 3D shape of the Crab to two other supernova remnants. Remarkably, they found that all three remnants had ejecta arranged in large-scale rings, suggesting a history of turbulent mixing and radioactive plumes expanding from a collapsed iron core.

This 3D reconstruction of the Crab Nebula is made of 406,472 individual points where nebular emission has been detected in SITELLE spectra. The velocity of each element has been translated into a spatial position by assuming an unaccelerated outward motion. The glowing blue sphere at the centre is artificial and simulates the continuum emitted by the pulsar wind nebula. The Milky Way background (credit: NASA / Goddard Space Flight Center Scientific Visualization Studio) simulates the perspective as observed when moving around the nebula. The soundtrack is a sonification of the data set: using the interferograms directly as a sound wave, multiple samples have been mixed and played at different rates. The sound volume is proportional to the distance to the nebula, and the playing speed simulates the Doppler effect.
<iframe width="704" height="418" src="https://www.youtube.com/embed/_nFuzp7COFQ" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
Credit: Thomas Martin, Danny Milisavljevic and Laurent Drissen

Co-author Dan Milisavljevic, an assistant professor at Purdue University and supernova expert, concludes that the fascinating morphology of the Crab seems to go against the most popular explanation of the original explosion.

“The Crab is often understood as being the result of an electron-capture supernova triggered by the collapse of an oxygen-neon-magnesium core, but the observed honeycomb structure may not be consistent with this scenario,” Milisavljevic said.

The new reconstruction was made possible by the ground-breaking technology used by SITELLE, which incorporates a Michelson interferometer design allowing scientists to obtain over 300,000 high-resolution spectra of every single point of the nebula.

“SITELLE was designed with objects like the Crab Nebula in mind; but its wide field of view and adaptability make it ideal to study nearby galaxies and even clusters of galaxies at large distances,” said co-author Laurent Drissen.

Supernova explosions are among the most energetic and influential phenomena in the universe. Consequently, Milisavljevic adds: “It is vital that we understand the fundamental processes in supernovae which make life possible. SITELLE will play a new and exciting role in this understanding.”



Contacts and sources:
Dr. Morgan Hollis, Royal Astronomical Society
Dr Thomas Martin. Université Laval
Dr Dan Milisavljevic, Purdue University


Publication: “3D mapping of the Crab Nebula with SITELLE. I. Deconvolution and kinematic reconstruction”, T. Martin, L. Drissen, D. Milisavljevic, Monthly Notices of the Royal Astronomical Society (2021), in press (DOI: 10.1093/mnras/staa4046).

The paper is available from: https://doi.org/10.1093/mnras/staa4046




Ardi's Ancient Skeletal Hand Could Reveal Evolutionary Secrets

 A 4.4 million-year-old skeleton could show how early humans moved and began to walk upright, according to new research led by a Texas A&M anthropology professor.

The skeletal fragments of “Ardi.”


Wikimedia Commons



Evolutionary expert Charles Darwin and others recognized a close evolutionary relationship between humans, chimps and gorillas based on their shared anatomies, raising some big questions: how are humans related to other primates, and exactly how did early humans move around? Research by a Texas A&M University professor may provide some answers.

Thomas Cody Prang, assistant professor of anthropology, and colleagues examined the skeletal remains of Ardipithecus ramidus (“Ardi”), dated to 4.4 million years old and found in Ethiopia. One of Ardi’s hands was exceptionally well-preserved.

The researchers compared the shape of Ardi’s hand to hundreds of other hand specimens representing recent humans, apes and monkeys (measured from bones in museum collections around the world) to make comparisons about the kind of locomotor behavior used by the earliest hominins (fossil human relatives).

The results provide clues about how early humans began to walk upright and make similar movements that all humans perform today.

This discovery is described in a study published in the current issue of Science Advances.

“Bone shape reflects adaptation to particular habits or lifestyles – for example the movement of primates – and by drawing connections between bone shape and behavior among living forms, we can make inferences about the behavior of extinct species, such as Ardi, that we can’t directly observe, Prang said.

“Additionally, we found evidence for a big evolutionary ‘jump’ between the kind of hand represented by Ardi and all later hominin hands, including that of Lucy’s species (a famous 3.2 million-year-old well-preserved skeleton found in the same area in the 1970s). This ‘evolutionary jump’ happens at a critical time when hominins are evolving adaptations to a more human-like form of upright walking, and the earliest evidence for hominin stone-tool manufacture and stone-tool use, such as cut-marks on animal fossils, are discovered.”

Prang said the fact that Ardi represents an earlier phase of human evolutionary history is important because it potentially shines light on the kind of ancestor from which humans and chimpanzees evolved.

“Our study supports a classic idea first proposed by Charles Darwin in 1871, when he had no fossils or understanding of genetics, that the use of the hands and upper limbs for manipulation appeared in early human relatives in connection with upright walking,” he said. “The evolution of human hands and feet probably happened in a correlated fashion.”

Since Ardi is such an ancient species, it might retain skeletal features that were present in the last common ancestor of humans and chimpanzees. If this is true, it could help researchers place the origin of the human lineage – in addition to upright walking – into a clearer light.

“It potentially brings us one step closer to an explanation for how and why humans evolved our form of upright walking,” Prang said.

He added that the big change in hand anatomy between Ardi and all later hominins occurs at a time, roughly between 4.4 and 3.3 million years ago, coinciding with the earliest evidence of the loss of a grasping big toe in human evolution. This also coincides with the earliest known stone tools and stone cut-marked animal fossils.

He said it appears to mark a major change in the lifestyle and behavior of human relatives within this timeframe.

“We propose that it involves the evolution of more advanced upright walking, which enabled human hands to be modified by the evolutionary process for enhanced manual manipulation, possibly involving stone tools,” Prang said

This research was funded by the Wenner Gren Foundation.





Contacts and sources:
By Keith Randall 
Texas A&M University 











Light-Emitting Smart Tattoo Engineered for the First Time

Scientists at UCL and the IIT –Istituto Italiano di Tecnologia (Italian Institute of Technology) have created a temporary tattoo with light-emitting technology used in TV and smartphone screens, paving the way for a new type of “smart tattoo” with a range of potential uses.

The technology, which uses organic light-emitting diodes (OLEDs), is applied in the same way as water transfer tattoos. That is, the OLEDs are fabricated on to temporary tattoo paper and transferred to a new surface by being pressed on to it and dabbed with water.
Credit: Barsotti – Italian Institute of Technology


The researchers, who described the process in a new paper in the journal Advanced Electronic Materials, say it could be combined with other tattoo electronics to, for instance emit light when an athlete is dehydrated, or when we need to get out of the sun to avoid sunburn. OLEDs could be tattooed on packaging or fruit to signal when a product has passed its expiry date or will soon become inedible, or used for fashion in the form of glowing tattoos.

Professor Franco Cacialli (UCL Physics & Astronomy), senior author of the paper, said: “The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply. They can be combined with other forms of tattoo electronics for a very wide range of possible uses. These could be for fashion – for instance, providing glowing tattoos and light-emitting fingernails. In sports, they could be combined with a sweat sensor to signal dehydration.

“In healthcare they could emit light when there is a change in a patient’s condition – or, if the tattoo was turned the other way into the skin, they could potentially be combined with light-sensitive therapies to target cancer cells, for instance.

“Our proof-of-concept study is the first step. Future challenges will include encapsulating the OLEDs as much as possible to stop them from degrading quickly through contact with air, as well as integrating the device with a battery or supercapacitor.”

The OLED device the researchers developed is 2.3 micrometres thick in total (less than one 400th of a millimetre) – about a third of the length of a single red blood cell. It consists of an electroluminescent polymer (a polymer that emits light when an electric field is applied) in between electrodes. An insulating layer is placed in between the electrodes and the commercial tattoo paper.

Credit: Barsotti – Italian Institute of Technology

The light-emitting polymer is 76 nanometres thick (a nanometre is a millionth of a millimetre) and was created using a technique called spin coating, where the polymer is applied to a substrate which is spun at high speed, producing an extremely thin and even layer.

Once they had built the technology, the team applied the tattooable OLEDs, which emitted green light, on to a pane of glass, a plastic bottle, an orange, and paper packaging.

Senior author Professor Virgilio Mattoli, researcher at Italian Institute of Technology said: “Tattoo electronics is a fast-growing field of research. At the Italian Institute of Technology we have previously pioneered electrodes that we have tattooed onto people’s skin that can be used to perform diagnostic tests such as electrocardiograms. The advantage of this technology is that it is low-cost, easy to apply and use, and washes off easily with soap and water.”

OLEDs were first used in a flatscreen TV 20 years ago. Among the advantages of the technology are that they can be used on flexible, bendy surfaces, and that they can be made from liquid solvents. This means they are printable, providing a cheap way to create bespoke new OLED designs




Contacts and sources:
Mark Greaves
University College London


Publication: Ultrathin, Ultra‐Conformable, and Free‐Standing Tattooable Organic Light‐Emitting Diodes.
Jonathan Barsotti, Alexandros G. Rapidis, Ikue Hirata, Francesco Greco, Franco Cacialli, Virgilio Mattoli.Advanced Electronic Materials, 2021; 2001145 DOI: 10.1002/aelm.202001145




The Earliest Know Primate Fossils Paint a Picture of Life After Dinosaur Extinction



Shortly after the extinction of the dinosaurs, the earliest known archaic primates, such as the newly described species Purgatorius mckeeveri shown in the foreground, quickly set themselves apart from their competition — like the archaic ungulate mammal on the forest floor — by specializing in an omnivorous diet including fruit found up in the trees.

Credit: Andrey Atuchin

A new study published Feb. 24 in the journal Royal Society Open Science documents the earliest-known fossil evidence of primates.

A team of 10 researchers from across the U.S. analyzed several fossils of Purgatorius, the oldest genus in a group of the earliest-known primates called plesiadapiforms. These ancient mammals were small-bodied and ate specialized diets of insects and fruits that varied by species. These newly described specimens are central to understanding primate ancestry and paint a picture of how life on land recovered after the Cretaceous-Paleogene extinction event 66 million years ago that wiped out all dinosaurs — except for birds — and led to the rise of mammals.

Gregory Wilson Mantilla, a University of Washington professor of biology and curator of vertebrate paleontology at the UW’s Burke Museum of Natural History & Culture, co-led the study with Stephen Chester of Brooklyn College and the City University of New York. The team analyzed fossilized teeth found in the Hell Creek area of northeastern Montana. The fossils, which are now part of the collections at the University of California Museum of Paleontology, are estimated to be 65.9 million years old, about 105,000 to 139,000 years after the mass extinction event. Based on the age of the fossils, the team estimates that the ancestor of all primates —including plesiadapiforms and today’s primates such as lemurs, monkeys and apes — likely emerged by the Late Cretaceous and lived alongside large dinosaurs.

“It’s mind blowing to think of our earliest archaic primate ancestors,” said Wilson Mantilla. “They were some of the first mammals to diversify in this new post-mass extinction world, taking advantage of the fruits and insects up in the forest canopy.”

The fossils include two species of Purgatorius: Purgatorius janisae and a new species described by the team named Purgatorius mckeeveri. Three of the teeth found have distinct features compared to any previously known Purgatorius species and led to the description of the new species.


High resolution CT scans of an assortment of fossilized teeth and jaw bones of Purgatorius.


Credit: Gregory Wilson Mantilla/Stephen Chester

Purgatorius mckeeveri is named after Frank McKeever, who was among the first residents of the area where the fossils were discovered, and also the family of John and Cathy McKeever, who have since supported the field work where the oldest specimen of this new species was discovered.

“This was a really cool study to be a part of, particularly because it provides further evidence that the earliest primates originated before the extinction of non-avian dinosaurs,” said co-author Brody Hovatter, a UW graduate student in Earth and space sciences. “They became highly abundant within a million years after that extinction.”

“This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record,” said Chester. “It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.”

Co-author on the study was the late William Clemens who was a professor emeritus at the University of California, Berkeley and former director of the UC Museum of Paleontology. Additional co-authors are Jason Moore and Wade Mans of the University of New Mexico; Courtney Sprain of the University of Florida; William Mitchell of Minnesota IT Services; Roland Mundil of the Berkeley Geochronology Center; and Paul Renne of UC Berkeley and the Berkeley Geochronology Center. The research was funded by the National Science Foundation, the UC Museum of Paleontology, the Myhrvold and Havranek Charitable Family Fund, the UW, the CUNY and the Leakey Foundation.



Contacts and sources:
Andrea Godinez
University of Washington, Burke Museum of Natural History & Culture


 




Coal and COVID-19: How the Pandemic Is Accelerating the End of Fossil Power Generation

COVID-19 has not only caused a temporary drop in global CO2 emissions, it has also reduced the share of power generated by burning coal – a trend that could in fact outlast the pandemic. This is the key result of a new study by a team of economists based in Potsdam and Berlin that looked at COVID-19's impact on the energy system and demand for electricity. Their findings show that the pandemic, while putting a terrible toll on people’s lives and the economy, has also opened a window of opportunity to make this current trend of decreasing coal use irreversible: Supported by the right climate policy measures, power sector emissions could decline more rapidly than previously thought.

Coal-fired power plant outside of Fairbanks, Alaska. 
Photo: NOAA/Unsplash


“Coal has been hit harder by the Corona crisis than other power sources– and the reason is simple,” explains lead author Christoph Bertram from the Potsdam Institute for Climate Impact Research (PIK). “If demand for electricity drops, coal plants are usually switched off first. This is because the process of burning fuels constantly runs up costs. The plant operators have to pay for each single ton of coal. In contrast, renewable power sources such as wind and solar plants, once built, have significantly lower running costs – and keep on operating even if the demand is reduced.”

This way, fossil fuels were partly squeezed out of the electricity generation mix in 2020 and global CO2 emissions from the power sector decreased around 7%. By looking at India, the USA, and European countries alone a more dramatic picture emerges: In these key markets, where monthly electricity demand declined by up to 20% compared to 2019, the monthly CO2 emissions decreased by up to 50%.

The researchers estimate that it’s likely that emissions will not reach the all-time high of 2018 anymore. “Due to the ongoing crisis, we expect that 2021 electricity demand will be at about 2019's levels, which, given ongoing investments into low-carbon generation means lower fossil generation than in that year” says co-author Gunnar Luderer from PIK. “As long as this clean electricity generation growth exceeds increases in electricity demand, CO2 emissions from the power sector will decline. Only if we saw unusually high demand for electricity along with surprisingly few additions of renewable power plants from 2022-2024 and beyond, fossil fuel generation would rebound to pre-pandemic levels.”

While the power sector has seen a dynamic transformation process even before the advent of COVID-19, the pandemic has weakened the market position of coal-fired power generation and illustrated its vulnerability.

“Our research shows that investing in fossil-fueled power is not only environmentally irresponsible – it is economically very risky,” says co-author Ottmar Edenhofer, Director of both PIK and the Mercator Research Institute on Global Commons and Climate Change. “In the end, it will certainly take carbon pricing to cut emissions at the required pace and stabilize our Climate. Yet the impacts of the Corona crisis on the power generation sector have put political leaders in a unique position: Along with additional policies such as eliminating subsidies for fossil fuels and increasing investments in wind and solar power, it is now easier than ever before to put an end to high-carbon electricity.”



Contacts and sources:
Potsdam Institute for Climate Impact Research (PIK)


Publication: COVID-induced low power demand and market forces starkly reduce CO2 emissions.  Christoph Bertram, Gunnar Luderer, Felix Creutzig, Nico Bauer, Falko Ueckerdt, Aman Malik, Ottmar Edenhofer (2021):  Nature Climate Change [DOI: 10.1038/s41558-021-00987-x]




Life on Mars: Implications of Microbes Surviving Deep beneath Earth's Seafloor on Byproducts of Radioactivity


 A team of researchers from the University of Rhode Island’s Graduate School of Oceanography and their collaborators have revealed that the abundant microbes living in ancient sediment below the seafloor are sustained primarily by chemicals created by the natural irradiation of water molecules.

The results have implications for life on Mars

Justine Sauvage, lead author of the study, measures dissolved oxygen content in sediment cores collected in the North Atlantic. 
Photo courtesy of Justine Sauvage

The team discovered that the creation of these chemicals is amplified significantly by minerals in marine sediment. In contrast to the conventional view that life in sediment is fueled by products of photosynthesis, an ecosystem fueled by irradiation of water begins just meters below the seafloor in much of the open ocean. This radiation-fueled world is one of Earth’s volumetrically largest ecosystems.

The research was published today in the journal Nature Communications.

“This work provides an important new perspective on the availability of resources that subsurface microbial communities can use to sustain themselves. This is fundamental to understand life on Earth and to constrain the habitability of other planetary bodies, such as Mars,” said Justine Sauvage, the study’s lead author and a postdoctoral fellow at the University of Gothenburg who conducted the research as a doctoral student at URI.

Marine sediment samples used in the irradiation experiments.

Photo courtesy of Justine Sauvage

The process driving the research team’s findings is radiolysis of water – the splitting of water molecules into hydrogen and oxidants as a result of being exposed to naturally occurring radiation. Steven D’Hondt, URI professor of oceanography and a co-author of the study, said the resulting molecules become the primary source of food and energy for the microbes living in the sediment.

“The marine sediment actually amplifies the production of these usable chemicals,” he said. “If you have the same amount of irradiation in pure water and in wet sediment, you get a lot more hydrogen from wet sediment. The sediment makes the production of hydrogen much more effective.”

Why the process is amplified in wet sediment is unclear, but D’Hondt speculates that minerals in the sediment may “behave like a semiconductor, making the process more efficient.”

The discoveries resulted from a series of laboratory experiments conducted in the Rhode Island Nuclear Science Center. Sauvage irradiated vials of wet sediment from various locations in the Pacific and Atlantic Oceans, collected by the Integrated Ocean Drilling Program and by U.S. research vessels. She compared the production of hydrogen to similarly irradiated vials of seawater and distilled water. The sediment amplified the results by as much as a factor of 30.

“This study is a unique combination of sophisticated laboratory experiments integrated into a global biological context,” said co-author Arthur Spivack, URI professor of oceanography.

The implications of the findings are significant.

“If you can support life in subsurface marine sediment and other subsurface environments from natural radioactive splitting of water, then maybe you can support life the same way in other worlds,” said D’Hondt. “Some of the same minerals are present on Mars, and as long as you have those wet catalytic minerals, you’re going to have this process. If you can catalyze production of radiolytic chemicals at high rates in the wet Martian subsurface, you could potentially sustain life at the same levels that it’s sustained in marine sediment.”

Sauvage added, “This is especially relevant given that the Perseverance Rover has just landed on Mars, with its mission to collect Martian rocks and to characterize its habitable environments.”

D’Hondt said the research team’s findings also have implications for the nuclear industry, including for how nuclear waste is stored and how nuclear accidents are managed. “If you store nuclear waste in sediment or rock, it may generate hydrogen and oxidants faster than in pure water. That natural catalysis may make those storage systems more corrosive than is generally realized,” he said.

The next steps for the research team will be to explore the effect of hydrogen production through radiolysis in other environments on Earth and beyond, including oceanic crust, continental crust and subsurface Mars. They also will seek to advance the understanding of how subsurface microbial communities live, interact and evolve when their primary energy source is derived from the natural radiolytic splitting of water.

This study was supported by the U.S. National Science Foundation and the U.S. National Aeronautics and Space Administration. The project is also affiliated with the Center for Dark Energy Biosphere Investigations.


Contacts and sources:
Todd McLeish 
University of Rhode Island