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An investigation into levels of methylmercury in a small sampling of commercial dog food offers good news for dog owners.

Of the 24 diets tested, only three were positive for low concentrations of total mercury, and only one of those contained detectable methylmercury.

“The concentrations detected are unlikely to pose a risk to healthy adult dogs,” says lead author Rae Sires, a nutrition resident at the University of California, Davis Veterinary Medical Teaching Hospital. “These results should be reassuring to dog owners.”

Excess mercury exposure is a health hazard for people and animals. Depending on the method of exposure—such as skin contact, ingestion, or inhalation—it can lead to respiratory and gastrointestinal disease, kidney injury, impacted fetal development, and neurologic issues. While previous studies have measured total mercury in commercial pet foods, additional testing for methylmercury had taken place.

“That is the form where we worry about bioaccumulation or the ability to become more concentrated in animal tissues as it moves through the food chain,” Sires says. “We know there is some level of total mercury in commercial dog foods based on recent studies, but we didn’t yet know whether it is cause for concern.”

Because methylmercury is known for its presence in aquatic species, Sires said the researchers evaluated diets containing fish—mostly salmon—and control samples, which didn’t have fish-based ingredients. Out of the 24 diets tested, only three were positive for low concentrations of total mercury, and only one of those contained detectable methylmercury.

Surprisingly, Sires says they found two of the three positive samples among the non-fish diets, suggesting that common sources of mercury in pet foods may not originate from seafood.

Sires acknowledged this study included a relatively small sample size. She says it should be viewed as a jumping-off point for further research that could expand to cover more samples and completed over a longer period of time and seasons.

“We need more data to determine where the total mercury detected in dog foods is coming from, but our study doesn’t support avoiding fish or salmon-based diets,” Sires says.

Sires completed the project as part of her residency training and presented the findings at the recent Veterinary Resident & Intern Research Symposium. The study also appears in Topics in Companion Animal Medicine.

Funding came via the Center for Companion Animal Health at the UC Davis School of Veterinary Medicine.

Source: UC Davis

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Researchers have identified an evolutionary function in wild tomato plants that modern plant breeders could use to create pest-resistant tomatoes.

The study traced the evolution of a specific gene that produces a sticky compound in the tips of the trichomes, or hairs, on the Solanum pennellii plant found in the Atacama desert of Peru—one of the harshest environments on Earth. These sticky hairs act as natural insect repellants to protect the plant, helping ensure it will survive to reproduce.

“We identified a gene that exists in this wild plant, but not in cultivated tomatoes,” says Rob Last, professor of plant biochemistry at Michigan State University.

“The invertase-like enzyme creates insecticidal compounds not found in the garden-variety tomato. This defensive trait could be bred into modern plants.”

“…how can we increase crop yield by creating a pest-resistant plant and eliminate the need to spray fields with insecticides?”

Last explains that modern cultivated tomatoes make fewer of the compounds found in wild plants because—unaware of their adaptive function—breeders removed undesirable traits such as stickiness.

Bryan Leong, plant biology graduate student and co-lead author, is interested in how the wild plants evolved to be insect-resistant.

“We want to make our current tomatoes adapt to stress like this wild tomato, but we can only do that by understanding the traits that make them resistant,” says Leong.

“We are using evolution to teach us how to be better breeders and biologists. For example, how can we increase crop yield by creating a pest-resistant plant and eliminate the need to spray fields with insecticides?”

Advances in technology allowed the team to apply genetic and genomic approaches, including the CRISPR gene-editing technology, to the wild tomato plant to discover the functions of specific genes, metabolites, and pathways.

Using these new techniques, the team identified an invertase-like enzyme specific to the cells at the tips of the sticky hairs. Invertases regulate many aspects of growth and development in plants. In the wild tomato, the enzyme evolved to facilitate the production of new insecticidal compounds.

“Plants are amazing biochemical factories…”

“It is a race over evolutionary time between the consumed and the consumers,” says Leong.

“Insects benefit by eating the plants. Yet, evolution favors plants that make more seeds and pass on their genes to another generation. We hope to take the defensive lessons plants already learned and apply them to existing crops.”

This discovery is a step toward understanding the natural insect resistance of Solanum pennellii plants, which could enable introduction of this trait into cultivated tomatoes using traditional breeding practices.

“Plants are amazing biochemical factories that make many unusual compounds with protective, medicinal, and economically important properties,” says Cliff Weil, a program director at the National Science Foundation, which funded this study.

“In this study, the authors found that a common enzyme has been repurposed for forming such compounds, giving us important insight into how life is able to bend existing tools for novel uses.”

The study appears in Science Advances. A National Institutes of Health Plant Biotechnology for Health and Sustainability graduate training grant funded the study.

Source: Michigan State University

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Researchers have identified the genomic features that might have made domestication possible for corn and soybeans, two of the world’s most critical crop species.

The research has implications for how scientists understand domestication, the process by which humans have been able to breed plants for desirable traits through centuries of cultivation. The researchers drew on vast amounts of data on the genomes of corn and soybeans and compared particular sections of wild species and domestic varieties, noting where the genomes diverged most markedly.

The researchers studied more than 100 accessions from comparisons of corn with teosinte, its progenitor species. They also looked at 302 accessions from a dataset of wild and domesticated soybeans.

“We sliced the genomes into specific sections and compared them,” says Jianming Yu, professor of agronomy and chair in maize breeding at Iowa State University.

“These patterns in genome-wide base changes offer insight into how domestication affects the genetics of species…”

“It’s a fresh angle not many have looked at concerning genome evolution and domestication. We searched for ‘macro-changes,’ or major genome-wide patterns—and we found them.”

Human cultivation created a bottleneck in the genetic material associated with corn and soybeans, Yu says. As humans selected for particular traits they found desirable in their crops, they limited the genetic variation available in the plant’s genome. However, the researchers found several areas in the genomes of the species involved in the study where genome divergence seemed to concentrate.

“These patterns in genome-wide base changes offer insight into how domestication affects the genetics of species,” says first author Jinyu Wang, a graduate student in agronomy.

Variation in nucleotide bases between wild and domesticated species appeared more pronounced in non-genic portions of the genomes, or the parts of the genomes that do not code for proteins. The study also found greater variation in pericentromeric regions, or in areas near the centromere of chromosomes, and in areas of high methylation, or areas in which methyl groups are added to a DNA molecule. Methylation can change the activity of a DNA segment without changing its sequence.

The study looked at the occurrence of mutations in the genomes of the domesticated crops and their progenitor species.

“We now think it’s likely that good candidates for domestication, such as corn and soybeans, occupy a middle ground in their willingness to mutate,” says coauthor Xianran Li, adjunct associate professor of agronomy.

“If there’s no mutation, then everything stays the same and we don’t have evolution,” Yu says. “But too many mutations can wipe out a species.”

The study’s findings point to important links between UV radiation from the sun and genome evolution. UV radiation is a natural mutagen, and it leaves a special footprint when it occurs, Yu says. The study’s authors found many more of these footprints in modern corn and soybeans than their wild relatives.

The research appears in the journal Genome Biology.

The researchers worked with scientists at the University of Georgia, Cornell University, and the University of Minnesota. Funding for the research came from the National Science Foundation, the Iowa State University Raymond F. Baker Center for Plant Breeding, and the Iowa State University Plant Sciences Institute.

Source: Iowa State University

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The females and males of many wild bee species visit very different flowers for food, say researchers.

In fact, the diets of female and male bees of the same species could be as different as the diets of different bee species, according to a study in PLOS ONE.

“As we get a better sense of what makes flowers attractive to different kinds of bees, maybe we can get smarter about bee conservation,” says lead author Michael Roswell, a doctoral student in the lab of senior author Rachael Winfree, a professor in the department of ecology, evolution, and natural resources at Rutgers University-New Brunswick.

Five years ago, when Winfree Lab members were evaluating federally funded programs to create habitat for pollinators, Roswell noticed that some flowers were very popular with male bees and others with females. That spurred a study to test, for as many wild bee species as possible, whether males and females visit different kinds of flowers.

New Jersey is home to about 400 species of wild bees—not including Apis mellifera Linnaeus, the domesticated western honeybee whose males do not forage for food, Roswell notes.

The scientists collected 18,698 bees from 152 species in New Jersey. The bees visited 109 flower species in six semi-natural meadows with highly abundant and diverse flowers. The meadows were managed to promote mostly native flowers that attract pollinators.

Female bees build, maintain, collect food for and defend nests, while male bees primarily seek mates. Both sexes drink floral nectar for food, but only females collect pollen that serves as food for young bees, so they forage at greater rates than males.

From the flowers’ standpoint, both female and male bees are important pollinators—though female bees are more prolific because they spend more time foraging at flowers.

Before mating, the males of some species travel from the area where they were born. Targeting their preferences for flowers may help maintain genetically diverse bee populations, Roswell speculates.

“We see some intriguing patterns, where certain plant families seem relatively preferred or avoided by male bees, or where males have relatively less appetite for visiting flowers that only produce pollen and not nectar,” he says. “That could help pinpoint the right mix of flowers to improve bee conservation down the road.”

Source: Rutgers University

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Whether you’re chanting at a protest, partying at a concert, or cheering at a football game, there’s a special kind of excitement that comes from being in a crowd. Émile Durkheim called this “collective effervescence,” and today sociologists use this term to talk about the bubbly emotion that comes from being in the middle of the action.

One of the tricky parts of studying collective effervescence is figuring out what exactly supercharges these social interactions. Does it come from the simple fact that you’re in a crowd, or is it in the way people engage with each other when they get there? If we think about the morning commute or the line at the grocery store, most crowds seem pretty unpleasant and not so effervescent. Recent research published in Sociological Science by Lasse Suonperä Liebst sheds light on the answer with a super fun approach to data collection.

To track collective effervescence, a team of researchers showed up at The Roskilde Festival—one of Europe’s largest music festivals—to survey attendees about whether their camping experiences were “festive, noisy, hectic, boring, or calm.” 

The survey was sampled by a team of 11 university students during the five warm-up days of the festival, which precede the scheduled music program. During this period, tens of thousands of visitors build tent camps and engage in extensive drinking and partying activities. As such, the festival offered a “natural laboratory” (Park 1939) to examine the factors underpinning the collective effervescence that prior studies have identified in this (Pedersen 2014) and similar festival contexts (Niekrenz 2014).

Lasse Suonperä Liebst – “Exploring the Sources of Collective Effervescence: A Multilevel Study.” Sociological Science.

The survey team also collected respondents’ gender, age, previous festival attendance, how much their camp sites were interacting with others, and how much they personally enjoyed the party atmosphere. Then, they used aerial photography to map out how dense the festival crowds were and how close each campsite was to the central stage. 

With all this information collected, statistical models showed that individual preferences for partying did have a positive relationship the with reported level of collective effervescence at their campsite. However, the aerial measure of crowd density was a much stronger predictor of these reports—stronger than attendees’ own accounts of how often their camps were hanging out with others.

These results help us understand how collective effervescence happens, because they show how even just being near a crowd can “sweep people up” into a festive state. We often assume that crowds are stressful unless people choose to be in them or have positive, one-on-one interactions once inside. It is true that context matters—the grocery store queue probably won’t spark a party anytime soon—but this research shows the power of space and place for shaping our social lives.

(View original at https://thesocietypages.org/socimages)

Barnacles that hitch rides on the backs of humpback and gray whales not only record details about the whales’ yearly travels, but also hang on to the information after they fossilize.

That helps scientists reconstruct the migrations of whale populations millions of years in the past, according to a new study.

Oxygen isotope ratios in barnacle shells change with ocean condition and allow scientists to chart the migration of the host whale, for example to warmer breeding grounds or colder feeding grounds.

Now, marine paleobiologists have discovered that barnacles retain this information even after they fall off the whale, sink to the ocean bottom, and become fossils.

As a result, the travels of fossilized barnacles can serve as a proxy for the peregrinations of whales in the distant past, like GPS trackers from the Pleistocene.

“One of the more exciting things about the paper, in my mind, is that we find evidence for migration in all of these ancient populations, from three different sites and time periods, but also from both humpback and gray whale lineages, indicating that these animals, which lived hundreds of thousands of years ago, were all undertaking migrations similar in extent to those of modern-day whales,” says lead author Larry Taylor, a doctoral student at the University of California, Berkeley.

One surprise finding: different subpopulations of humpback whales have used the coast of Panama as a meeting ground for at least 270,000 years and still do today. Whales visit Panama from as far away as Antarctica and the Gulf of Alaska.

Changing climate

The new findings about ancient migration will help scientists understand how migration patterns may have affected the evolution of whales over the past 3 to 5 million years and how these patterns changed with changing climate. The findings will also help predict how today’s whales will adapt to the rapid climate change happening today.

“We want to understand how malleable migratory behavior has been through time, how rapidly whales have adapted to previous climate changes, and see if this can give us some clues as to how they might respond to the current changes in Earth’s climate,” Taylor says. “How will whales cope with that, how will the food base shift, how will the whales themselves respond?”

Barnacles are crustaceans, like crabs, lobsters, and shrimp, that remain stuck in one place their whole lives, encased in a protective hard shell and sticking out their legs to snatch passing food.

Most glue themselves to rocks, boats, or pilings, but whale barnacles attach to a whale’s skin by boring down into it. Some whales carry up to 1,000 pounds of barnacles, visible when they breech. Scientists use clusters of barnacles to identify individual whales.

“This gives the barnacle several advantages: a safe surface to live on, a free ride to some of the richest waters in the world, and a chance to meet up with other (barnacles) when the whales get together to mate,” says Aaron O’Dea, of the Smithsonian Tropical Research Institute in Panama.

Ancient migrations

Taylor’s technique works because different species of whale barnacle hitch rides on different species of whale, so paleontologists can know, when they find a fossilized barnacle, which species it rode with. Normally, the barnacles stay with a whale between one and three years, until they fall or get brushed off, often at whale breeding grounds. Scientists have found at least 24 fossil assemblages of whale barnacles around the world, Taylor says.

The new discovery means that the fossilized barnacles recovered at these sites reveal a lot about ancient migrations of humpbacks, gray whales, and perhaps other baleen whales (toothed whales, such as sperm whales, don’t host many barnacles), potentially turning up previously unsuspected feeding and breeding areas.

The technique is based on measuring the oxygen isotopes in the calcium carbonate, or calcite, shell of the barnacle. The ratio of oxygen-18 to oxygen-16 goes up as the temperature drops.

Since barnacles lengthen their shells by a few millimeters a month as they try to stay attached to whales in the face of the mammals’ shedding skin, the composition of the new shell reflects the ocean temperature and general isotopic composition where it formed.

Taylor built on previous work showing that barnacles attached to living gray whales record a chemical signature of their migrations. He confirmed that the isotopic composition of the humpback whale barnacle (Coronula diadema) also tracks its environment today during the whales’ yearly migration, showing monthly changes.

He then demonstrated that scientists could similarly analyze fossilized barnacles from Panama and from the California coast, and that they showed isotopic changes similar to that of today’s whales.

This technique will be particularly valuable for studying prehistoric humpback populations, Taylor says, because the humpback was and is more cosmopolitan than the California gray whale, cruising widely through the Pacific and Atlantic oceans.

Scientists theorize that whale migration began as food sources became more scattered as the climate changed 5 million years ago. Modern Pacific whales migrate tens of thousands of miles annually, visiting several known feeding areas and returning to warm waters off Central and South America or Hawaii to breed.

“We plan to push this approach further back in time and across different whale populations,” says senior author Seth Finnegan, an associate professor of integrative biology at UC Berkeley.

“We hope that by analyzing other aspects of the geochemistry of the barnacles shells we might ultimately be able to figure out what areas different ancient whale populations were migrating to.”

Timothy Bralower of Penn State contributed to the study, which appears in the Proceedings of the National Academy of Sciences. The National Science Foundation, the National System of Investigators in Panama, the Paleontological Society, the Geological Society of America, Sigma Xi, and the University of California Museum of Paleontology funded the work.

Source: UC Berkeley

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Researchers are looking at a mixture of bee spit and flower oil to create a bio-inspired glue.

Why? Its unique adhesive properties and ability to remain sticky through a range of conditions.

Honey bees spend hours each day collecting pollen and packing it into tidy bundles attached to their hind legs. But all of that hard work could instantly be undone during a sudden rainstorm were it not for two substances the insect uses to keep the pollen firmly stuck in place: bee spit and flower oil.

“A bee encounters not just wet and humid environments but windy and dry surroundings as well, so its pollen pellet must counteract those variations in humidity while remaining adhered,” says J. Carson Meredith, a professor in Georgia Tech’s School of Chemical and Biomolecular Engineering. “Being able to withstand those kinds of changes in humidity is still a challenge for synthetic adhesives.”

In a study in Nature Communications, the researchers described how those two natural liquids work together to protect the bee’s bounty as it travels back to its hive.

Better together

The first component of the glue is the bee’s own salivary secretions, which coat the pollen grains and allow them to stick together. The bees produce those sugary secretions, the main ingredient in honey, from nectar they drink from the flowers.

The second ingredient is a plant-based oil that coats the pollen grains called pollenkitt, which helps stabilize the adhesive properties of the nectar and protect it from the impact of too much or too little humidity.

“It works similarly to a layer of cooking oil covering a pool of syrup,” Meredith says. “The oil separates the syrup from the air and slows down drying considerably.”

The researchers tested the adhesive properties of the bee’s glue by separating the oil-based component from the sugar-based component and evaluating how sticky the nectar remained under various humidity conditions.

As expected, as humidity increased and the nectar absorbed more water, its adhesive properties diminished. The same effect was true when humidity decreased and the nectar dried out. Meanwhile, under similar conditions, nectar coated with the pollenkitt oil remained sticky despite changes in humidity.

Perfect for sticky situations

“We believe you could take the essential concepts of this material and develop a novel adhesive with a water-barrier external oil layer that could better resist humidity changes in the same way,” Meredith says. “Or potentially this concept would apply to controlling the working time of an adhesive, such as its ability to flow and time to dry or cure.”

The research team also examined dynamics of the bee adhesive.

“We wanted to know, if the pollen can stay so firmly attached to the bee’s hind legs, how do the bees manage to remove it when they return to the hive,” Meredith says.

The answer may lie in the adhesive’s a rate-sensitive response. In other words, the faster the force attempting to remove it, the more it would resist.

“This is a property of capillary adhesion, which we believe could be harnessed and tailored for specific applications, such as controlling motion in microscopic or nanoscale devices, in fields ranging from construction to medicine,” Meredith says.

The Air Force Office of Scientific Research supported the research. Any conclusions or recommendations are those of the authors and do not necessarily represent the official views of the sponsoring organizations.

Source: Georgia Tech

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Meltwater from Greenland’s ice sheet contributes to global sea level rise. An under-appreciated factor—the snowline’s position on the ice sheet—plays a key role in the melting’s pace, a new study shows.

Researchers used satellite imagery to track the movement of the ice sheet’s snowline—the elevation above where the surface is snow-covered—and below where bare ice is exposed.

The findings show that snowline elevation varies significantly from year to year, and that its variation exerts an outsized influence on the amount of solar radiation the ice sheet absorbs. Changes in snowline elevation from year to year explain more than half of the annual radiation variability on the ice sheet, researchers say.

Ultimately, the amount of radiation the ice sheet absorbs determines the extent to which it melts.

“People who study alpine glaciers have recognized the importance of snowlines for years, but no one had explicitly studied them in Greenland before,” says Laurence C. Smith, a visiting fellow at the Institute at Brown for Environment and Society (IBES) and a coauthor of the paper in Science Advances.

“This study shows for the first time that this simple partitioning between bare ice and snow matters more when it comes to melting than a whole host of other processes that receive more attention.”

Snow cover and bare ice

The results have significant implications for predicting future sea-level rise, researchers say. Meltwater from Greenland’s ice sheet is a large contributor to global sea levels, and the findings show that regional climate models used to predict future runoff often predict snowlines inaccurately.

“We found that models don’t reproduce snowlines very well, which adds an uncertainty to future projections,” says lead author Jonathan C. Ryan, a postdoctoral researcher at Brown University. “But now that we’ve shown how important the snowline effect is, and have some direct observations of snowline positions, hopefully we can improve these models going forward.”

The reason that the snowline is so important has to do with the difference in reflectivity between snow cover and bare ice. Snow is extremely bright and reflects back into the atmosphere the lion’s share of the sunlight it receives.

Bare ice is much darker, and therefore reflects less radiation. Instead, more radiation is absorbed, which heats the ice and leads to melting.

Scientists have well understood these processes for years. What wasn’t known was the extent to which they play out on the Greenland ice sheet, and to what extent snowline migration might regulate melt from year to year.

“That’s a surprise because there’s been a lot of work lately on these ice-darkening processes,” Smith says. “It turns out that in this case, we were missing the elephant in the room, which is the snowline.”

Having established the importance of snowline in energy absorption—and ultimately in melting and runoff—the researchers wanted to see if regional climate models properly captured the effect of the snowline. That’s important because scientists use those models predict future runoff from the Greenland ice sheet.

Too high, too low

Two leading models both fail to capture snowline elevation accurately. One model, known as MAR, set snowlines too high and was therefore likely overestimating runoff in high-melt years. The other model, known as RACMO, set the snowlines too low, meaning it likely underestimates future runoff in a warmer climate.

Given the importance of snowline position, researchers say it’s important the models get the snowline right.

“We’re collaborating now with the modelers, providing them with our observed snowlines,” Ryan says. “That gives them some ground truth they should be able to use to adjust their models. Now there’s something to aim for.”

More accurate forecasts of Greenland’s future contributions to sea-level rise would follow improvements to the modeling snowline, the researchers say.

The NASA Cryosphere Program funded the work.

Source: Brown University

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A new measurement technique may finally dissolve doubts about the quality of quantum dots.

Quantum dots—tiny, easy-to-produce particles—may soon take the place of more expensive single crystal semiconductors in advanced electronics found in solar panels, camera sensors, and medical imaging tools.

Although quantum dots have begun to break into the consumer market—in the form of quantum dot TVs—long-standing uncertainties about their quality have hampered their adoption.

“Traditional semiconductors are single crystals, grown in vacuum under special conditions. These we can make in large numbers, in flask, in a lab and we’ve shown they are as good as the best single crystals,” says co-lead author David Hanifi, a graduate student in chemistry at Stanford University.

The researchers focused on how efficiently quantum dots reemit the light they absorb, one telltale measure of semiconductor quality. While previous attempts to figure out quantum dot efficiency hinted at high performance, this is the first measurement method to confidently show they could compete with single crystals.

‘Giant leap’

The measurement technique could lead to the development of new technologies and materials that require knowing the efficiency of our semiconductors to a painstaking degree, says Paul Alivisatos, professor of nanoscience and nanotechnology at the University of California, Berkeley.

“We want to measure emission efficiencies in the realm of 99.9 to 99.999 percent…”

“These materials are so efficient that existing measurements were not capable of quantifying just how good they are. This is a giant leap forward,” says Alivisatos.

“It may someday enable applications that require materials with luminescence efficiency well above 99 percent, most of which haven’t been invented yet.”

Being able to forego the need for pricey fabrication equipment isn’t the only advantage of quantum dots. Even prior to this work, there were signs that quantum dots could approach or surpass the performance of some of the best crystals.

They are also highly customizable. Changing their size changes the wavelength of light they emit, a useful feature for color-based applications such as tagging biological samples, TVs, or computer monitors.

Defect check

Despite these positive qualities, the small size of quantum dots means that it may take billions of them to do the work of one large, perfect single crystal. Making so many of these quantum dots means more chances for something to grow incorrectly, more chances for a defect that can hamper performance.

Techniques that measure the quality of other semiconductors previously suggested quantum dots emit over 99 percent of the light they absorb but that was not enough to answer questions about their potential for defects. To do this, the researchers needed a measurement technique better suited to precisely evaluating these particles.

“We want to measure emission efficiencies in the realm of 99.9 to 99.999 percent because, if semiconductors are able to reemit as light every photon they absorb, you can do really fun science and make devices that haven’t existed before,” says Hanifi.

The researchers’ technique involved checking for excess heat produced by energized quantum dots, rather than only assessing light emission because excess heat is a signature of inefficient emission. This technique, commonly used for other materials, had never been applied to measure quantum dots in this way and it was 100 times more precise than what others have used in the past. They found that groups of quantum dots reliably emitted about 99.6 percent of the light they absorbed (with a potential error of 0.2 percent in either direction), which is comparable to the best single-crystal emissions.

“It was surprising that a film with many potential defects is as good as the most perfect semiconductor you can make,” says co-senior author Alberto Salleo, professor of materials science and engineering.

Contrary to concerns, the results suggest that the quantum dots are strikingly defect-tolerant. The measurement technique is also the first to firmly resolve how different quantum dot structures compare to each other—quantum dots with precisely eight atomic layers of a special coating material emitted light the fastest, an indicator of superior quality. The shape of those dots should guide the design for new light-emitting materials, says Alivisatos.

Proof of efficiency

A next step in this project is developing even more precise measurements. If the researchers can determine that these materials reach efficiencies at or above 99.999 percent, that opens up the possibility for technologies we’ve never seen before. These could include new glowing dyes to enhance our ability to look at biology at the atomic scale, luminescent cooling, and luminescent solar concentrators, which allow a relatively small set of solar cells to take in energy from a large area of solar radiation.

All this being said, the measurements they’ve already established are a milestone of their own, likely to encourage a more immediate boost in quantum dot research and applications.

“People working on these quantum dot materials have thought for more than a decade that dots could be as efficient as single crystal materials,” says Hanifi, “and now we finally have proof.”

The research appears in Science. Additional coauthors are from Lawrence Berkeley National Laboratory, UC Berkeley, JXTG Nippon Oil & Energy Corporation in Japan, Hasselt University in Belgium, and Eindhoven University of Technology in the Netherlands. The Department of Energy, the European Research Council, and JXTG Nippon Oil & Energy funded this work.

Source: Stanford University

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Black and Latino teen boys stopped by the police report more frequent engagement in delinquent behavior from that point on, according to a new study.

The research also demonstrates that police stops have a negative impact on these adolescents’ psychological well-being.

“Our findings indicate that the single most common proactive policing strategy—directing officers to make contact with individual boys and young men in ‘high crime’ areas—may impose a terrible cost on black and Latino youth across the country,” says study author Juan Del Toro, doctoral candidate in the Steinhardt School’s applied psychology department at New York University.

“Police stops are associated with harmful outcomes including subsequent delinquent behavior and psychological distress that may be even more harmful when they occur earlier in boys’ lives. These consequences warrant urgent attention from social scientists and policymakers.”

The more often a boy was stopped by the police, the more frequent his engagement with criminal behavior was.

Police agencies across the country have sought out to reduce crimes by shifting to what is known as “proactive policing”—proactively deploying officers to places where crime is likely to be reported and to engage with people most likely to be accused of those crimes.

A recent review of research demonstrates that proactive policing is associated with reduced crime, however, the same research also acknowledges that proactive policing can negatively affect the public legitimacy of law enforcement and even push people to avoid law-related officials altogether.

The research also ignores the potentially negative effects of proactive policing on racial disparities or youth criminality. The new research by Del Toro addresses the research gap by studying and finding that police stops increase the likelihood that black and Latino adolescents’ will engage in subsequent delinquent behavior.

Del Toro’s research focused on boys, and nonwhite boys in particular, because they are far more likely to experience police stops, arrests, or other contact with law enforcement compared to their peers.

Del Toro points to New York City where in 2016, more than 90 percent of people subjected to police stops were male—out of those, 52 percent black, 29 percent Latino, 10 percent white. Forty-seven percent were juveniles aged 14-24. Of the juveniles who experienced police encounters, only 7.2 percent were female and 7.5 percent were white.

The younger a boy was the first time he was stopped, the greater the increase in subsequent delinquent behavior six months later.

Del Toro and his team recruited boys from six public high schools in high-intensity policing neighborhoods and studied their encounters with law enforcement over two years. The boys in the sample self-identified as Latino (57.5 percent of the sample), black (23.1 percent of the sample), and other nonwhite (19.4 percent of the sample). All boys were equally susceptible to police stops and encounters, regardless of their prior engagement with delinquency.

The research also found that the more often a boy was stopped by the police, the more frequent his engagement with criminal behavior was six, 12, and 18 months later. Past criminal behavior did not predict more police encounters.

Additionally, psychological distress partially mediated the relationship between police stops and subsequent delinquency. The younger a boy was the first time he was stopped, the greater the increase in subsequent delinquent behavior six months later.

Additional coauthors are from the Urban Institute; the Center for Policing Equity; Second Measure; the City University of New York; and Stanford University.

The research appears in Proceedings of the National Academy of Sciences.

Source: New York University

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Scientists have figured out a way to feed electricity to microbes to grow truly green, biodegradable bioplastics, according to a new study.

The research comes from the idea that engineers can use electricity harvested from the sun or wind interchangeably with power from coal or petroleum sources. Or they can turn sustainably produced electricity into something physical and useful.

“As our planet grapples with rampant, petroleum-based plastic use and plastic waste, finding sustainable ways to make bioplastics is becoming more and more important,” says Arpita Bose, assistant professor of biology at Washington University in St. Louis. “We have to find new solutions.”

Renewable energy currently accounts for about 11 percent of total US energy consumption and about 17 percent of electricity generation.

One of the main issues with renewable electricity is energy storage—how to collect power generated during the sunny and windy hours, and hold it for when it is dark and still. Bioplastics are a good use for that “extra” power from intermittent sources, Bose suggests—as an alternative to battery storage, and instead of using that energy to make a different type of fuel.

Bose’s laboratory is among the first to use microbial electrosynthesis to wrangle a polymer called polyhydroxybutyrate (PHB) from electricity-eating microbes. The plastic they are making is “sustainable, carbon-neutral, and low-cost,” Bose says.

“One of the major challenges in bioplastic production is the substrate input, which affects cost,” says first author Tahina Ranaivoarisoa, a research technician in the Bose laboratory.

“A versatile bacterium such as R. palustris TIE-1—which can effectively use just carbon dioxide, light, and electrons from electricity or iron for bioplastic production—broadens the substrates that could be used in bioplastic production.”

In a related paper in Bioelectrochemistry, Bose’s research team illustrates how TIE-1 interacts with various forms of iron while also using electricity as a source of electrons. The researchers manually coating electrodes that the microbes used with a special kind of rust to improve production rates for PHB, which increased their electricity uptake.

Bose believes that microbially derived bioplastics have a future role to play in space, where astronauts could use 3D printer technology to manufacture their own tools instead of transporting everything ready-made from Earth.

“Our observations open new doors for sustainable bioplastic production not only in resource-limited environments on Earth, but also during space exploration and for in situ resource utilization on other planets,” Bose says.

The Department of Energy, the Department of Defense, the Army Research Office, and the David and Lucile Packard Foundation funded the work, which appears in the Journal of Industrial Microbiology and Biotechnology.

Source: Washington University in St. Louis

The post Electricity-eating microbes could make bioplastics appeared first on Futurity.

Torrie's restaurant is located at 700 V St NW. BreAnna Bell / DCist

Torrie's Restaurant holds D.C. memorabilia inside. BreAnna Bell / DCist

Celebrity photos line the walls of the restaurant. BreAnna Bell / DCist

To remember the late mayor, Torrie's Restaurant dedicated a booth to Marion Barry, a well known customer of Torrie's. BreAnna Bell / DCist

Photos of past U.S. presidents decorate the wall facing the entrance of Torrie's. BreAnna Bell / DCist

"Greek Alley" is a wall dedicated to African American Greek life in the diner. BreAnna Bell / DCist

On most weekdays, you’d be hard-pressed to find any hustle and bustle inside Torrie’s, the red-walled restaurant across from Howard University Hospital. Saturday and Sunday, however, tell a different story: The place fills with crowds hungry for a plate of homestyle-cooked food from the all-day breakfast menu. One DCist reader thinks it’s time the 20-year old restaurant got some buzz.

“You guys have done stories on Ben’s Chili Bowl and Florida Avenue Grill, but I’ve never seen anything about Torrie’s down the block from [the 9:30 Club],” Akio Stribling, a longtime D.C. resident and patron of the restaurant, wrote to DCist. “Howard students have been going there for ages, but I’d love to know the back story.”

Torrie’s captures the essence of D.C. and its black community with its decor: The diner is covered wall to wall with signed photos of famous past guests—like Pam Grier and The Five Heartbeats—and local celebrities, including D.C. news anchors and radio host Prince DaJour. There’s also memorabilia from the “Divine Nine” African American Greek organizations, many of which were founded at Howard University, just blocks away from the restaurant.

In addition to its soul food-packed menu, which includes delicacies like scrapple and chitterlings, the small staff warmly greets guests and makes them feel at home with conversations over the counter. “It’s a real diner experience,” Stribling says. “It’s a kind of restaurant that’s just disappearing.”

In the time since owner John Goodwin took over Torrie’s in 1996, he’s seen the neighborhood in the heart of “Chocolate City” welcome new businesses and mixed-use developments. However, with the changes, Goodwin says he’s also witnessed a large number of the once predominantly black population and black-owned businesses disappear from the area.

In 1990, the area surrounding Howard University was 78 percent black. By 2010, the black population of the neighborhood had decreased to 44 percent. Along with the change in demographics, the average household income had increased drastically. The median household income in 1989 for Shaw was $61,652. The number climbed to $146,883 between 2011-2015.

Additionally, property values skyrocketed. The median home price in 1995 sat at $147,000. By 2016, homes in the area were being sold for $846,000. High-end developments moved in, including The Shay and its revolving door of retail concepts, which currently include local boutique Lettie Gooch and the perfume shop Le Labo. Just a block away from Torrie’s is Atlantic Plumbing, which houses a Landmark movie theater and ramen restaurant Haikan. Units at The Shay start at approximately $1,900; Atlantic Plumbing studios start at around $1,700.

“Our base has left the area,” Goodwin says.

Before it was Torrie’s, 700 V Street NW was a host of eateries over the years. Past Howard University students including Denzel Gordon, a frequenter of Torrie’s for 20 years, remember the building as a McDonald’s, then a Roy Roger’s Chicken shop, but additional details are scarce. In the early 1990’s, D.C.’s historic Gospel Spreading Church, located right next door, purchased the property in an effort to, according to the church’s treasurer James Stokes, stop the possibility of a business such as a liquor store from moving in.

The restaurant became Wilson’s in 1994. Named after its then-owner Joe Wilson, the son of Lacey Wilson Sr. of Florida Avenue Grill, the Southern restaurant attracted customers with its promise of home style meals at affordable prices, a motto that Goodwin has continued in his ownership. Goodwin acquired the restaurant and changed its name in 1996.

In addition to the restaurant operation, Torrie’s also caters to halfway houses, senior citizen care facilities, and childcare facilities like Tucker’s Childhood Development Center in Southeast. The catering business has allowed Torrie’s to keep prices steady, Goodwin says, “so we can continue to feed the people around us.”

Torrie’s is also known to open its doors on Christmas to feed the community, including military veterans, people experiencing homelessness, and seniors, with a traditional down south meal.

“My belief is that someone ought to stay and be here for the people,” Goodwin says. “We do a lot for the community and we deal with a smaller staff. Everything here is made from scratch and we don’t waste anything.”

Loyal customers continue to partake in the Torrie’s experience. “It’s a part of D.C.’s black historic landmarks.” Desma Blocker, another long-time Torrie’s diner, tells DCist as she slides into a booth dedicated to former D.C. Mayor Marion Barry, a frequent customer. It’s located just inches from the restaurant’s memorial photo of D.C. civil rights activist, comedian, and Torrie’s customer Dick Gregory. “It’s had stars and all this history in the walls here,” says Blocker.

Gordon says he continues to support Torrie’s because “basically we love supporting black entrepreneurs because there aren’t many around here.”

Goodwin says he’s not fazed by the changes to the neighborhood around Torrie’s. “We are like a mountain in the area that won’t be destroyed because of gentrification,” he says.

This story is part of our food coverage generated by reader questions. Ask your own question below:

The post ‘It’s The Kind Of Restaurant That’s Just Disappearing’: 20 Years In, Torrie’s Remains A Landmark In Shaw appeared first on DCist.