Thursday, December 19, 2019

Robot experiment shows people trust robots more when robots explain what they are doing

by Bob Yirka , Tech Xplore

A team of researchers from the University of California Los Angeles and the California Institute of Technology has found via experimentation that humans tend to trust robots more when they communicate what they are doing. In their paper published in the journal Science Advances, the group describes programming a robot to report what it was doing in different ways and then showed it in action to volunteers.

As robots become more advanced, they are expected to become more common—we may wind up interacting with one or more of them on a daily basis. Such a scenario makes some people uneasy—the thought of interacting or working with a machine that not only carries out specific assignments, but does so in seemingly intelligent ways might seem a little off-putting. Scientists have suggested one way to reduce the anxiety people experience when working with robots is to have the robots explain what they are doing.

In this new effort, the researchers noted that most work being done with robots is focused on getting a task done—little is being done to promote harmony between robots and humans. To find out if having a robot simply explain what it is doing might reduce anxiety in humans, the researchers taught a robot to unscrew a medicine cap—and to explain what it was doing as it carried out its task in three different ways.

The first type of explanation was called symbolic, or mechanistic, and it involved having the robot display on a video screen each of the actions it was performing as part of a string of actions, e.g. grasp, push or twist. The second type of explanation was called haptic, or functional. It involved displaying the general function that was being performed as a robot went about each step in a task, such as approaching, pushing, twisting or pulling. Volunteers who watched the robot in action were also shown a simple text message that described what the robot was going to do.

The researchers then asked 150 volunteers to watch as the robot opened a medicine bottle along with accompanying explanations. The researchers report that the volunteers gave the highest trust ratings when they were shown both the haptic and symbolic explanations. The lowest ratings came from those who saw just the text message. The researchers suggest their experiment showed that humans are more likely to trust a robot if they are given enough information about what the robot is doing. They say the next step is to teach robots to report why they are performing an action.

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Video of combined symbolic and haptic explanation by the robot. Credit: Edmonds et al., Sci. Robot. 4, eaay4663 (2019)

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Video of haptic explanation. Credit: Edmonds et al., Sci. Robot. 4, eaay4663 (2019)

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Video of symbolic explanation. Credit: Edmonds et al., Sci. Robot. 4, eaay4663 (2019)

Video of summary text-only explanation. Credit: Edmonds et al., Sci. Robot. 4, eaay4663 (2019)

health care — Video of summary text-only explanation. Credit: Edmonds et al., Sci. Robot. 4, eaay4663 (2019)

Smelly, poisonous molecule may be a sure-fire sign of extraterrestrial life

by Jennifer Chu, Massachusetts Institute of Technology

Phosphine is among the stinkiest, most toxic gases on Earth, found in some of the foulest of places, including penguin dung heaps, the depths of swamps and bogs, and even in the bowels of some badgers and fish. This putrid "swamp gas" is also highly flammable and reactive with particles in our atmosphere.

Most life on Earth, specifically all aerobic, oxygen-breathing life, wants nothing to do with phosphine, neither producing it nor relying on it for survival.

Now MIT researchers have found that phosphine is produced by another, less abundant life form: anaerobic organisms, such as bacteria and microbes, that don't require oxygen to thrive. The team found that phosphine cannot be produced in any other way except by these extreme, oxygen-averse organisms, making phosphine a pure biosignature—a sign of life (at least of a certain kind).

In a paper recently published in the journal Astrobiology, the researchers report that if phosphine were produced in quantities similar to methane on Earth, the gas would generate a signature pattern of light in a planet's atmosphere. This pattern would be clear enough to detect from as far as 16 light years away by a telescope such as the planned James Webb Space Telescope. If phosphine is detected from a rocky planet, it would be an unmistakable sign of extraterrestrial life.

"Here on Earth, oxygen is a really impressive sign of life," says lead author Clara Sousa-Silva, a research scientist in MIT's Department of Earth, Atmospheric and Planetary Sciences. "But other things besides life make oxygen too. It's important to consider stranger molecules that might not be made as often, but if you do find them on another planet, there's only one explanation."

The paper's co-authors include Sukrit Ranjan, Janusz Petkowski, Zhuchang Zhan, William Bains, and Sara Seager, the Class of 1941 Professor of Earth, Atmospheric, and Planetary Sciences at MIT, as well as Renyu Hu at Caltech.

Giant bellies

Sousa-Silva and her colleagues are assembling a database of fingerprints for molecules that could be potential biosignatures. The team has amassed more than 16,000 candidates, including phosphine. The vast majority of these molecules have yet to be fully characterized, and if scientists were to spot any of them in an exoplanet's atmosphere, they still wouldn't know whether the molecules were a sign of life or something else.

But with Sousa-Silva's new paper, scientists can be confident in the interpretation of at least one molecule: phosphine. The paper's main conclusion is that, if phosphine is detected in a nearby, rocky planet, that planet must be harboring life of some kind.

The researchers did not come to this conclusion lightly. For the last 10 years, Sousa-Silva has devoted her work to fully characterizing the foul, poisonous gas, first by methodically deciphering phosphine's properties and how it is chemically distinct from other molecules.

In the 1970s, phosphine was discovered in the atmospheres of Jupiter and Saturn—immensely hot gas giants. Scientists surmised that the molecule was spontaneously thrown together within the bellies of these gas giants and, as Sousa-Silva describes, "violently dredged up by huge, planet-sized convective storms."

Still, not much was known about phosphine, and Sousa-Silva devoted her graduate work at University College of London to pinning down phosphine's spectral fingerprint. From her thesis work, she nailed down the exact wavelengths of light that phosphine should absorb, and that would be missing from any atmospheric data if the gas were present.

During her Ph.D., she began to wonder: Could phosphine be produced not just in the extreme environments of gas giants, but also by life on Earth? At MIT, Sousa-Silva and her colleagues began answering this question.

"So we started collecting every single mention of phosphine being detected anywhere on Earth, and it turns out that anywhere where there's no oxygen has phosphine, like swamps and marshlands and lake sediments and the farts and intestines of everything," Sousa-Silva says. "Suddenly this all made sense: It's a really toxic molecule for anything that likes oxygen. But for life that doesn't like oxygen, it seems to be a very useful molecule."

"Nothing else but life"

The realization that phosphine is associated with anaerobic life was a clue that the molecule could be a viable biosignature. But to be sure, the group had to rule out any possibility that phosphine could be produced by anything other than life. To do this, they spent the last several years running many species of phosphorous, phosphine's essential building block, through an exhaustive, theoretical analysis of chemical pathways, under increasingly extreme scenarios, to see whether phosphorous could turn into phosphine in any abiotic (meaning non-life-generating) way.

Phosphine is a molecule made from one phosphorous and three hydrogen atoms, which normally do not prefer to come together. It takes enormous amounts of energy, such as in the extreme environments within Jupiter and Saturn, to smash the atoms with enough force to overcome their natural aversion. The researchers worked out the chemical pathways and thermodynamics involved in multiple scenarios on Earth to see if they could produce enough energy to turn phosphorous into phosphine.

"At some point we were looking at increasingly less-plausible mechanisms, like if tectonic plates were rubbing against each other, could you get a plasma spark that generated phosphine? Or if lightning hit somewhere that had phosphorous, or a meteor had a phosphorous content, could it generate an impact to make phosphine? And we went through several years of this process to figure out that nothing else but life makes detectable amounts of phosphine."

Phosphine, they found, has no significant false positives, meaning any detection of phosphine is a sure sign of life. The researchers then explored whether the molecule could be detectable in an exoplanet's atmosphere. They simulated the atmospheres of idealized, oxygen-poor, terrestrial exoplanets of two types: hydrogen-rich and carbon dioxide-rich atmospheres. They fed into the simulation different rates of phosphine production and extrapolated what a given atmosphere's spectrum of light would look like given a certain rate of phosphine production.

They found that if phosphine were produced at relatively small amounts equivalent to the amount of methane produced on Earth today, it would produce a signal in the atmosphere that would be clear enough to be detected by an advanced observatory such as the upcoming James Webb Space Telescope, if that planet were within 5 parsecs, or about 16 light years from Earth—a sphere of space that covers a multitude of stars, likely hosting rocky planets.

Sousa-Silva says that, aside from establishing phosphine as a viable biosignature in the search for extraterrestrial life, the group's results provide a pipeline, or process for researchers to follow in characterizing any other of the other 16,000 biosignature candidates.

"I think the community needs to invest in filtering these candidates down into some kind of priority," she says. "Even if some of these molecules are really dim beacons, if we can determine that only life can send out that signal, then I feel like that is a goldmine."

Addressing committed emissions in both US and China requires carbon capture and storage

by Ellis Robinson, Carnegie Mellon University Materials Science and Engineering

THE REALITY IS THAT CCS IS NOT GREEN NOR CLEAN IT IS GOING TO BE USED TO FRACK OLD DRY WELLS SUCH AS IN THE BAKAN SHIELD IN SASKATCHEWAN
https://plawiuk.blogspot.com/2014/10/the-myth-of-carbon-capture-and-storage.html

ALSO SEE https://plawiuk.blogspot.com/search?q=CCS

Stabilizing global temperatures will require deep reductions in carbon dioxide (CO2) emissions worldwide. Recent integrated assessments of global climate change show that CO2 emissions must approach net-zero by mid-century to avoid exceeding the 1.5°C climate target. However, "committed emissions," those emissions projected from existing fossil fuel infrastructure operating as they have historically, already threaten that 1.5°C goal. With the average lifespan of a coal plant being over 40 years, proposed or under-construction power plants only add to that burden, further increasing the challenge of achieving net-zero emissions by 2050.

The deep decarbonization required for net-zero emissions will require existing and proposed fossil-energy infrastructure to follow one of two pathways: either prematurely retiring or capturing and storing their emissions, thus preventing their release into the atmosphere. Carbon capture and storage (CCS), represents the only major viable path for fossil-fuel plants to be net-zero, short of being shuttered.

In a Viewpoint Article recently published in Environmental Science & Technology, Haibo Zhai outlines how the U.S. and China, the world's two largest emitters, should address their committed emissions. "In both countries, CCS retrofits to existing infrastructure are essential for reducing emissions to net-zero," said Zhai, an Associate Research Professor of Engineering and Public Policy at Carnegie Mellon University. However, differences in the power-plant fleets and the energy mix in the two countries point to separate routes for achieving deep decarbonization.

In the U.S., the energy landscape has changed dramatically over the past two decades. Coal was the dominant source of electricity (51% of total power generation in 2000) for most of the twentieth century, but has recently been displaced by cheap and abundant natural gas as well as growth in renewables. Coal accounted for just 27% of U.S. power generation in 2019. Coal's decline is expected to continue in favor of cheaper alternatives, due to the U.S."s relatively old (40 years) and inefficient (32% efficiency) fleet of coal-fired plants.

Zhai does not see CCS retrofits to U.S coal plants as a fleet-wide approach to decarbonization, though there is potential for partial capture at the most efficient plants. CCS development should instead be focused on combined-cycle natural gas plant retrofits. "Natural gas has helped reduce the carbon intensity of the U.S. power sector, but this wave of new gas plants still represents a significant amount of committed emissions," said Zhai.

China is the opposite of the U.S. in terms of its energy mix and its fossil energy infrastructure. Coal supplies almost 65% of the nation's electricity. Coal-fired plants in China have a median age of only 12 years and much higher efficiencies (often greater than 40%) compared to the U.S. "Such a young fleet is unlikely to be phased out anytime soon," said Zhai. "Any path for China to achieve deep decarbonization must include CCS retrofits to its recently-built coal plants."

Despite the necessity of CCS, the technology has not been proven on a large scale and remains very costly. Only two commercial-scale CCS projects currently operate in the world: Petra Nova in the U.S. and Boundary Dam in Canada. Current CCS technologies have high energy and capital costs associated with separating CO2 out of process waste streams.

CCS, according to Zhai, currently sits on the steep part of the "learning curve." With any technology first-of-a-kind deployments are always expensive. However, industry-wide learning—through technology developments such as improved separation materials and processes, supply chain expansion, and increases in operational efficiency—makes latter deployments cheaper. Moving down the learning curve represents a kind of chicken and egg dilemma for CCS: to be widely deployed, it needs to be cheap. And for CCS to be cheap, it needs to have been deployed.

Therefore, there is a strong reason that governments should incentivize early adoption of CCS through regulatory, economic, and policy means, argues Zhai. He points to case studies of other low-carbon technologies, like photovoltaic solar panels, that have become cost-competitive after incentives helped lower high initial costs. Because early deployment is required to make future deployment economical, the time to act is now, he says.

"If you accept the premise that committed emissions are a problem, there is no choice other than CCS," he said. "And incentives are required to kick-start deployment of CCS on the scale needed to address the issue."

In the U.S., Zhai points to incentives for retrofitting natural gas-fired plants with CCS, expecting market forces to address the committed emissions from coal-fired plants, as the aging coal fleet continues to phase out. Zhai's article points to a tax credit for carbon sequestration in the U.S. as a major policy lever to incentivize these CCS efforts.

In China, on the other hand, CCS development for coal plant retrofits should be the major focus. There, Zhai notes that the national emissions trading system, where emitters can buy or sell CO2 emissions credits, will be the major policy lever that can spur development of mitigation technologies. In both cases, the current high costs of CCS point to government policies as a key step in overcoming the expensive initial phases of deployment.

Major co-benefits of incentivizing CCS development for existing fossil-fuel infrastructure are the role CCS will likely play in certain negative emissions technologies (NETs) and a decreased dependence on expensive NETs in the future. Bioenergy with CCS (BECCS), for instance, is outlined as the most prominent NET option. However, a key subsystem for any BECCS is CCS. Developing CCS now, argues Zhai, means that BECCS will be poised to help address global climate change in the future.

Haibo Zhai. Deep Reductions of Committed Emissions from Existing Power Infrastructure: Potential Paths in the United States and China, Environmental Science & Technology (2019). DOI: 10.1021/acs.est.9b06858

Journal information: Environmental Science & Technology

Mealworms provide plastic solution

by Rob Jordan, Stanford University

Tiny mealworms may hold part of the solution to our giant plastics problem. Not only are they able to consume various forms of plastic, as previous Stanford research has shown, they can eat Styrofoam containing a common toxic chemical additive and still be safely used as protein-rich feedstock for other animals, according to a new Stanford study published in Environmental Science & Technology.

The study is the first to look at where chemicals in plastic end up after being broken down in a natural system—a yellow mealworm's gut, in this case. It serves as a proof of concept for deriving value from plastic waste.

"This is definitely not what we expected to see," said study lead author Anja Malawi Brandon, a Ph.D. candidate in civil and environmental engineering at Stanford. "It's amazing that mealworms can eat a chemical additive without it building up in their body over time."

In earlier work, Stanford researchers and collaborators at other institutions revealed that mealworms, which are easy to cultivate and widely used as a food for animals ranging from chickens and snakes to fish and shrimp, can subsist on a diet of various types of plastic. They found that microorganisms in the worms' guts biodegrade the plastic in the process—a surprising and hopeful finding. However, concern remained about whether it was safe to use the plastic-eating mealworms as feed for other animals given the possibility that harmful chemicals in plastic additives might accumulate in the worms over time.

"This work provides an answer to many people who asked us whether it is safe to feed animals with mealworms that ate Styrofoam", said Wei-Min Wu, a senior research engineer in Stanford's Department of Civil and Environmental Engineering who has led or co-authored most of the Stanford studies of plastic-eating mealworms.

Styrofoam solution

Brandon, Wu and their colleagues looked at Styrofoam or polystyrene, a common plastic typically used for packaging and insulation, that is costly to recycle because of its low density and bulkiness. It contained a flame retardant called hexabromocyclododecane, or HBCD, that is commonly added to polystyrene. The additive is one of many used to improve plastics' manufacturing properties or decrease flammability. In 2015 alone, nearly 25 million metric tons of these chemicals were added to plastics, according to various studies. Some, such as HBCD, can have significant health and environmental impacts, ranging from endocrine disruption to neurotoxicity. Because of this, the European Union plans to ban HBCD, and U.S. Environmental Protection Agency is evaluating its risk.

Mealworms in the experiment excreted about half of the polystyrene they consumed as tiny, partially degraded fragments and the other half as carbon dioxide. With it, they excreted the HBCD—about 90 percent within 24 hours of consumption and essentially all of it after 48 hours. Mealworms fed a steady diet of HBCD-laden polystyrene were as healthy as those eating a normal diet. The same was true of shrimp fed a steady diet of the HBCD-ingesting mealworms and their counterparts on a normal diet. The plastic in the mealworms' guts likely played an important role in concentrating and removing the HBCD.

The researchers acknowledge that mealworm-excreted HBCD still poses a hazard, and that other common plastic additives may have different fates within plastic-degrading mealworms. While hopeful for mealworm-derived solutions to the world's plastic waste crisis, they caution that lasting answers will only come in the form of biodegradable plastic replacement materials and reduced reliance on single-use products.

"This is a wake-up call," said Brandon. "It reminds us that we need to think about what we're adding to our plastics and how we deal with it."

Assessing heat wave risk in cities as global warming continues

by Bob Yirka , Phys.org

A trio of researchers with the Hong Kong University of Science and Technology, the University of Alabama in Huntsville and Arizona State University has shown that commuters traveling from the suburbs to cities in the future are going to encounter hotter than expected weather when in they reach their destination. In their paper published in the journal Science Advances, Jiachuan Yang, Leiqiu Hu and Chenghao Wang describe their study of the differences in temperature between actual readings and those that are forecast in urban areas and what it could mean for commuters as climate change continues.

Cities are hotter than outlying areas in the summer due to the materials that are used to make roads and buildings—asphalt, tar and cement hold a lot of heat. This has led to what scientists call the urban heat island effect. In this new effort, the researchers wondered what might happen to people in the future who live in the suburbs and commute into cities during heat waves as the planet becomes warmer. To find out, they accessed databases containing weather information to learn more about differences between forecast and actual temperatures in cities. They also accessed databases of census information, including commuting patterns.

The researchers found that temperatures were typically hotter in cities during heat waves than were predicted by weather forecasters. They also found that the amount varied. Salt Lake City, for example, had the biggest difference—the city was on average 3.8 degrees C hotter during heat waves than was forecast. Overall, the researchers found that out of the 16 cities they studied, temperatures were on average 1.9 degrees C higher than what forecasters predicted. They note that such temperatures are significant because they represent heat events where temperatures are already on average 3.6 degrees C hotter than normal. They note that mortality (people dying) and morbidity (people getting sick) is already problematic in many cities during heat waves. They further note that the problem is only going to get worse due to climate change. They suggest that commuters of the future may face unexpected hazards as they travel from the relatively cooler suburbs to the much hotter cites. They suggest also that city planners need to take such scenarios into consideration as they look to contend with climate change.

Stone throwing chimps appear to like the sound when it hits a tree

by Bob Yirka , Phys.org

A team of researchers from the Max Planck Institute of Evolutionary Anthropology and Aix-Marseille University has found evidence that suggests a group of chimpanzees who throw stones at trees appear to do so for the acoustical effect. In their paper published in the journal Biology Letters, the group describes experiments they carried out with stone throwing and trees and what they learned from them.

Three years ago, the team with this new effort discovered a surprising behavior by four groups of chimps in West Africa—they would individually lob stones at trees while simultaneously screaming. At the time, the researchers noted that the chimps appeared to have favorite trees for the stone lobbing—such trees had piles of stones at their bases. The four chimp groups were found in Liberia, Guinea-Bissau, Ivory Coast and Guinea. The researchers noted that the behavior appeared to be localized, which suggested its purpose was a local tradition. At the time, the researchers suggested the stone throwing was likely part of some ritual, though it was not clear what purpose the ritual might have served.

In this new effort, the same group of researchers sought to find out why the chimps were throwing the stones at the trees. Suspecting that there might be an acoustical connection, they made their way to the same place they had witnessed the stone throwing three years before and identified the trees that were the targets of the stones. They then set up microphones to capture the sounds that of stones tossed at the trees—to speed things up, they lobbed the stones themselves. They also set up microphones at other trees and threw stones at them, as well. In all, the researchers tested 13 different kinds of trees under various scenarios, noting how muted or bright the sounds were, how percussive and how long the sound persisted.

The researchers report that they found that the chimpanzees tended to favor certain tree species with exposed roots—they also found that when rocks struck the roots of such trees, the sounds were lower and lasted longer than was the case for other trees. The group suggests their findings indicate the chimps throw the stones at the trees because of the sound it makes—though they are still no closer to understanding why the chimps would care.

More information: Ammie K. Kalan et al. Chimpanzees use tree species with a resonant timbre for accumulative stone throwing, Biology Letters (2019). DOI: 10.1098/rsbl.2019.0747

Journal information: Biology Letters

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New archaeological discoveries reveal birch bark tar was used in medieval England

by University of Bristol

Scientists from the University of Bristol and the British Museum, in collaboration with Oxford Archaeology East and Canterbury Archaeological Trust, have, for the first time, identified the use of birch bark tar in medieval England—the use of which was previously thought to be limited to prehistory.

Birch bark tar is a manufactured product with a history of production and use that reaches back to the Palaeolithic. It is very sticky, and is water resistant, and also has biocidal properties mean that it has a wide range of applications, for example, as a multipurpose adhesive, sealant and in medicine.

Archaeological evidence for birch bark tar covers a broad geographic range from the UK to the Baltic and from the Mediterranean to Scandinavia.

In the east and north of this range there is continuity of use to modern times but in western Europe and the British Isles the use of birch bark tar has generally been viewed as limited to prehistory, with gradual displacement by pine tars during the Roman period.

The new identifications, reported today in the Journal of Archaeological Science: Reports, came from two early medieval sites in the east of England.

The first was a small lump of dark material found in a child grave of the Anglo-Saxon period (440-530AD) in Cambridge (analysed by the Organic Geochemistry Unit, University of Bristol, for Oxford Archaeology East).

The other tar (analysed by scientists at the British Museum) was discovered coating the interior of a ceramic container associated with a 5th-6th century cemetery site at Ringlemere in Kent.

The child in the Cambridge Anglo-Saxon period grave was likely a girl, aged seven to nine years old, and she had a variety of grave goods, including brooches and beads on her chest, and a variety of artefacts, including an iron knife, a copper alloy girdle hanger and an iron ring, together with the dark lump of material, all contained within a bag hanging from a belt at her waist.

The different contexts of the finds point to diverse applications of the material.

From pathological indicators on the child skeleton, the team surmise that the birch bark tar may have been used for medicinal purposes as birch bark tar has a long history in medicine, having antiseptic properties.

The tar in the ceramic vessel from Ringlemere might have been used for processing the tar or sealing the container.

Both of the tars were found to contain fatty material, possibly added to soften the tar, or, in the case of the container could indicate multiple uses.

Dr. Rebecca Stacey from the British Museum's Department of Scientific Research said: "The manufacturing and use of birch bark tar is well known is well known from prehistoric times but these finds indicate either a much longer continuity of use of this material than has been recognised before or perhaps a reintroduction of the technology in eastern regions at this time."

Dr. Julie Dunne, from the University of Bristol's School of Chemistry, added: "These results present the first identification of birch bark tar from early medieval archaeological contexts in the UK.

"Interestingly, they are from two different contexts, one in a ceramic pot, which suggests it may have been used to process birch bark into tar and the other as an 'unknown' lump in a child grave of the Anglo-Saxon period. The pathological indicators on the child skeleton suggests the birch bark tar may have been used for medicinal purposes."

Dr. Ian Bull, also from the University of Bristol's School of Chemistry, said: "This is a great example of how state-of-the-art chemical analyses have been able to re-characterise an otherwise mundane object as something of extreme archaeological interest, providing possible insights into medicinal practices in the Middle Ages."

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