It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
The new dinosaur is called Tralkasaurus, which means "thunder reptile" in the indigenous Mapuche language common in Patagonia. In this file photo, a boy in Melbourne, Australia inspects the teeth of a theropod dinosaur
The remains of a 90-million-year-old carnivorous dinosaur distantly related to Tyrannosaurus rex has been discovered in Argentine Patagonia by a team of paleontologists.
The four-meter-long (13-foot-long) theropod was discovered in February 2018 in the central Argentine province of Rio Negro.
Scientists have christened it Tralkasaurus cuyi, the National University of La Matanza's Scientific Disclosure Agency said on Thursday.
Tralkasaurus means "thunder reptile" in the indigenous Mapuche language common in Patagonia. Cuyi relates to the place the fossil remains were found, El Cuy.
Tralkasaurus would have been dwarfed by its distant cousin Tyrannosaurus rex which could grow to 14 meters in length.
"The size of the Tralkasaurus body is smaller than other carnivores in its group—the abelisaurids," said Dr Federico Agnolin, an investigator from the Argentine Museum of Natural Sciences.
Other abelisaurids usually measured seven to 11 meters.
This "demonstrates that the group of abelisaurid theropods encompassed a much wider ecological niche than we thought," said Mauricio Cerroni, another researcher.
The team found a skull, teeth, ribs and part of the hip and tail.
Just like Tyrannosaurus, it was a short-necked and muscular biped with four claws on each of its hind legs, and arms that were very short in comparison to the rest of its body. The bones of its extremities were light and hollow.
"This new discovery helps us to define the ecological habits of carnivorous dinosaurs as well as herbivores," said Cerroni.
According to the researchers, Tralkasaurus possibly fed on small herbivore dinosaurs called iguanodonts that have been found nearby by the same team of researchers.
More than half of all air-quality-related early deaths in the United States are a result of emissions originating outside of the state in which those deaths occur, MIT researchers report in the journal Nature.
The study focuses on the years between 2005 and 2018 and tracks combustion emissions of various polluting compounds from various sectors, looking at every state in the contiguous United States, from season to season and year to year.
In general, the researchers find that when air pollution is generated in one state, half of that pollution is lofted into the air and carried by winds across state boundaries, to affect the health quality of out-of-state residents and increase their risk of early death.
Electric power generation is the greatest contributor to out-of-state pollution-related deaths, the findings suggest. In 2005, for example, deaths caused by sulfur dioxide emitted by power plant smokestacks occurred in another state in more than 75 percent of cases.
Encouragingly, the researchers found that since 2005, early deaths associated with air pollution have gone down significantly. They documented a decrease of 30 percent in 2018 compared to 2005, equivalent to about 30,000 avoided early deaths, or people who did not die early as a result of pollution. In addition, the fraction of deaths that occur due to emissions in other states is falling—from 53 percent in 2005 to 41 percent in 2018.
Perhaps surprisingly, this reduction in cross-state pollution also appears to be related to electric power generation: In recent years, regulations such as the Environmental Protection Agency's Clean Air Act and other changes have helped to significantly curb emissions from this sector across the country.
The researchers caution, however, that today, emissions from other sectors are increasingly contributing to harmful cross-state pollution.
"Regulators in the U.S. have done a pretty good job of hitting the most important thing first, which is power generation, by reducing sulfur dioxide emissions drastically, and there's been a huge improvement, as we see in the results," says study leader Steven Barrett, an associate professor of aeronautics and astronautics at MIT. "Now it's looking like other emissions sectors are becoming important. To make further progress, we should start focusing on road transportation and commercial and residential emissions."
Barrett's coauthors on the paper are Sebastian Eastham, a research scientist at MIT; Irene Dedoussi, formerly an MIT graduate student and now an assistant professor at Delft University of Technology; and Erwan Monier, formerly an MIT research scientist and now an assistant professor at the University of California at Davis. The research was a collaboration between MIT's Laboratory for Aviation and the Environment and the MIT Joint Program on the Science and Policy of Global Change.
Death and the matrix
Scientists have long known that pollution observes no boundaries, one of the prime examples being acid rain.
"It's been known in Europe for over 30 years that power stations in England would create acid rain that would affect vegetation in Norway, but there's not been a systematic way to capture how that translates to human health effects," Barrett says.
In the case of the United States, tracking how pollution from one state affects another state has historically been tricky and computationally difficult, Barrett says. For each of the 48 contiguous states, researchers would have to track emissions to and from the rest of the 47 states.
"But now there are modern computational tools that enable you to do these assessments in a much more efficient way," Barrett says. "That wasn't really possible before."
He and his colleagues developed such tools, drawing on fundamental work by Daven Henze at the University of Colorado at Boulder, to track how every state in the contiguous U.S. affects pollution and health outcomes in every other state. They looked at multiple species of pollutants, such as sulfur dioxide, ozone, and fine particulates, from various emissions sectors, including electric power generation, road transportation, marine, rail, and aviation, and commercial and residential sources, at intervals of every hour of the year.
They first obtained emissions data from each of seven sectors for the years 2005, 2011, and 2018. They then used the GEOS-Chem atmospheric chemistry transport model to track where these emissions ended up, from season to season and year to year, based on wind patterns and a pollutant's chemical reactions to the atmosphere. Finally, they used an epidemiologically derived model to relate a population's pollutant exposure and risk of early death.
"We have this multidimensional matrix that characterizes the impact of a state's emissions of a given economic sector of a given pollutant at a given time, on any other state's health outcomes," Barrett says. "We can figure out, for example, how much NOx emissions from road transportation in Arizona in July affects human health in Texas, and we can do those calculations instantly."
Importing pollution
The researchers also found that emissions traveling out of state could affect the health of residents beyond immediate, neighboring states.
"It's not necessarily just the adjacent state, but states over 1,000 miles away that can be affected," Barrett says. "Different kinds of emissions have a different kind of range."
For example, electric power generation has the greatest range, as power plants can loft pollutants far into the atmosphere, allowing them to travel over long distances. In contrast, commercial and residential sectors generally emit pollutants that chemically do not last as long in the atmosphere.
"The story is different for each pollutant," Barrett says.
In general, the researchers found that out-of-state air pollution was associated with more than half of all pollution-related early deaths in the U.S. from 2005 to 2018.
In terms of the impact on individual states, the team found that many of the northern Midwest states such as Wyoming and North Dakota are "net exporters" of pollution-related health impacts, partly because the populations there are relatively low and the emissions these states generate are carried away by winds to other states. Those states that "import" health impacts tend to lie along the East Coast, in the path of the U.S. winds that sweep eastward.
New York in particular is what the researchers call "the biggest importer of air pollution deaths"; 60 percent of air pollution-related early deaths are from out-of-state emissions.
More information: Premature mortality related to United States cross-state air pollution, Nature (2020). DOI: 10.1038/s41586-020-1983-8 , https://nature.com/articles/s41586-020-1983-8
The secondhand smoke you're breathing may have come from another state
Secondhand smoke may come from many miles away. Credit: David Tadevosian/Shutterstock.com
Scientists estimate that each year in the U.S., outdoor air pollution shortens the lives of about 100,000 people by one to two decades.
As it turns out, much of this pollution originates not in a person's own neighborhood, but up to hundreds or even thousands of miles away in neighboring states. And, absent strong federal regulations, there's very little Americans can do about it.
In a study published on Feb. 12, we used state-of-the-art modeling to estimate the number of air pollution-related deaths that combustion emissions—those from any kind of burning, from cook stoves to car engines to coal power plants—from each state have caused in every other state over the past 14 years.
On average, 41% of these air pollution deaths in the U.S. resulted from what we call "secondhand smoke" emissions that crossed state lines.
This share has been declining over time, down from 53% in 2005, thanks in large part to reductions in sulfur dioxide emissions from the electric power sector. However, not every sector, or every state, has been a success story.
Secondhand smoke—but nationwide
The problem is like what people experience when they are exposed to secondhand cigarette smoke. The smoker endangers their own life the most, but the smoke that gets passed on still poses serious health risks to those exposed.
Outdoor air pollution works this way on a national scale. States emit pollution that, with rare exception, causes the most air quality issues for people within the same state. But that pollution also crosses state lines, leading to tens of thousands of additional early deaths.
Without strong regulations, people in neighboring states have no control over their exposure to "imported" air pollution. They will simply have to put up with it, just as restaurant diners or airline passengers used to do when seated near the smoking section.
Improvements and stagnation
We used estimates of combustion-related emissions from the U.S. Environmental Protection Agency's National Emissions Inventories. These estimates break down emissions by sector—rail, road, commercial and electricity generation—and chemical species—sulfur dioxide, nitrogen oxides and soot.
Using computer models of the movement and chemistry of air pollution, we were able to calculate the contribution that each sector made to pollution across the country, and how this has changed over time.
For example, we calculated that over 70% of all electricity generation-related early deaths occurred outside of the state in which the emitting plant is located.
In 2005, emissions from this source caused about 24,000 early deaths in the U.S. – 6,000 in the states where the plants were based, but 18,000 in other states. By 2018 those figures had dropped to 9,000 total.
Federal regulations—such as the Cross-State Air Pollution Rule and its predecessor, the Clean Air Interstate Rule – enabled this improvement by mandating reductions in power plant emissions of sulfur dioxide and nitrogen oxides. The EPA has made huge progress in this area by any standard.
Other sectors have been less successful. Although emissions from rail transportation have fallen over the same period, the total number of early deaths due to their emissions has stayed almost the same. This is due in part to the fact that the air is getting cleaner. As it does so, more pollution will form in response to the same emissions—regardless of the specific sector. Reductions in rail emissions have been too modest to compete with this change.
Meanwhile, early deaths due to emissions of fine particulate matter from the commercial and residential sectors, such as soot from heating and cooking, have increased, from around 20,000 early deaths in 2005 to 28,000 in 2018. Of these, about one-third came from activity originating in another state.
Different land, same air
The number of deaths occurring in each state is not uniform across the U.S., even in percentage terms. The different population densities, distributions and industrial compositions of each state also play a role, as does state policy.
For example, we found that only 3% of the total U.S. early deaths caused by California's combustion emissions are exported to other states. By contrast, Wyoming exports 96% of the early deaths from its emissions. That's because Wyoming is small, sparsely populated, upwind of the East Coast and has a large industrial base.
For any given state, these exports are mostly balanced by imported pollution from upwind states, but there are some notable exceptions. A case in point is the Northeast, which exports much of its own emissions out to the ocean.
Overall, our findings reflect the need not only for ongoing investigation of U.S. cross-state air pollution, but also for federal regulation that's strong enough to significantly reduce it and help save Americans' lives.
The Clean Air Interstate and Cross-State Air Pollution Rules have brought significant improvements, reflected in the overall downward trend we find for combustion air pollution-related deaths in the U.S. over the last 14 years. But more work at the national level is needed to bring these numbers down further.
Until then, states and their residents will continue to have no refuge from their neighbors' secondhand smoke.
How a tiny and strange marine animal produces unlimited eggs and sperm over its lifetime
Piwi1-positive spermatogonia are shown in yellow; cell nuclei are in turquoise. Germ cell induction and all stages of gametogenesis can be visualized in these clonal animals. Credit: Timothy DuBuc, Ph.D.Swarthmore College
A little-known ocean-dwelling creature most commonly found growing on dead hermit crab shells may sound like an unlikely study subject for researchers, but this animal has a rare ability—it can make eggs and sperm for the duration of its lifetime. This animal, called Hydractinia, does so because it produces germ cells, which are precursors to eggs and sperm, nonstop throughout its life. Studying this unique ability could provide insight into the development of human reproductive system and the formation of reproductive-based conditions and diseases in humans.
"By sequencing and studying the genomes of simpler organisms that are easier to manipulate in the lab, we have been able to tease out important insights regarding the biology underlying germ cell fate determination—knowledge that may ultimately help us better understand the processes underlying reproductive disorders in humans," Dr. Andy Baxevanis, director of the National Human Genome Research Institute's (NHGRI) Computational Genomics Unit and co-author of the paper. NHGRI is part of the National Institutes of Health.
In a study published in the journal Science, collaborators at NHGRI, the National University of Ireland, Galway, and the Whitney Laboratory for Marine Bioscience at the University of Florida, Augustine, reported that activation of the gene Tfap2 in adult stem cells in Hydractinia can turn those cells into germ cells in a cycle that can repeat endlessly.
In comparison, humans and most other mammals generate a specific number of germ cells only once in their lifetime. Therefore, for such species, eggs and sperm from the predetermined number of germ cells may be formed over a long period of time, but their amount is restricted. An international team of researchers have been studying Hydractinia's genome to understand how it comes by this special reproductive ability.
Timing of germ cell formation in Hydractinia versus most animals. Credit: Timothy DuBuc, Ph.D.Swarthmore College
Hydractinia lives in colonies and is closely related to jellyfish and corals. Although Hydractinia is dissimilar to humans physiologically, its genome contains a surprisingly large number of genes that are like human disease genes, making it a useful animal model for studying questions related to human biology and health.
Hydractinia colonies possess feeding polyps and sexual polyps as a part of their anatomy. The specialized sexual polyps produce eggs and sperm, making them functionally similar to gonads in species like humans.
During human embryonic development, a small pool of germ cells that will eventually become gametes is set aside, and all sperm or eggs that humans produce during their lives are the descendants of those original few germ cells. Loss of these germ cells for any reason results in sterility, as humans do not have the ability to replenish their original pool of germ cells.
In a separate study, Dr. Baxevanis at NHGRI and Dr. Christine Schnitzler at the Whitney Lab have completed the first-ever sequencing of the Hydractinia genome. In this study, researchers used this information to scrutinize the organism's genome for clues as to why there are such marked differences in reproductive capacity between one of our most distant animal relatives and ourselves.
Piwi1-positive oocytes are shown in yellow; cell nuclei are in turquoise. Germ cell induction and all stages of gametogenesis can be visualized in these clonal animals. Credit: Timothy DuBuc, Ph.D.Swarthmore College
"Having this kind of high-quality, whole-genome sequence data in hand allowed us to quickly narrow down the search for the specific gene or genes that tell Hydractinia's stem cells to become germ cells," said Dr. Baxevanis.
The researchers compared the behavior of genes in the feeding and sexual structures of Hydractinia. They found that the Tfap2 gene was much more active in the sexual polyps than in the feeding polyps in both males and females. This was a clue that the gene might be important in generating germ cells.
The scientists next confirmed that Tfap2 was indeed the switch that controls the process of perpetual germ cell production. The researchers used the CRISPR-Cas9 gene-editing technique to remove Tfap2 from Hydractinia and measured the resulting effects on germ cell production. They found that removing Tfap2 from Hydractinia stops germ cells from forming, bolstering the theory that Tfap2 controls the process.
The researchers also wanted to know if Tfap2 was influencing specific cells to turn into germ cells. Their analysis revealed that Tfap2 only causes adult stem cells in Hydractinia to turn into germ cells.
Interestingly, the Tfap2 gene also regulates germ cell production in humans, in addition to its involvement in myriad other processes. However, in humans, the germ cells are separated from non-germ cells early in development. Still, despite the vast evolutionary distance between Hydractinia and humans, both share a key gene that changes stem cells into germ cellsResearch could be step toward lab-grown eggs and sperm to treat infertility
Environmentally friendly textile material is easy and cheap to manufacture
by University of Borås
Mostafa Jabbari demonstrates the solvent which is applied onto the plyamide textile. Credit: University of Borås
When doctoral student Mostafa Jabbari began his research project, the aim was to improve the properties of the material used for textile bioreactors. But he changed tracks and developed a whole new textile material with better properties than was the original goal. The material is lighter, stronger, more heat and weather resistant, cheaper to manufacture, uses fewer chemicals, and is 100% recyclable. Mixed materials that cannot be recycled
"In the first part of my project, I modified an existing material to improve its insulating properties to withstand temperature changes. But there were two problems: One was that the adhesion between the two constituents, that is, the material that forms a sealing layer, did not have sufficient adhesion properties and the coating didn't stay adhered. The other problem was the recyclability, meaning that it was a blended material, one material for the fabric itself and another for the coating, which makes it extremely difficult to recycle, if not impossible," he says.
The second part of the project was, therefore, to use the same material in both the textile and the coating. Polyamide would prove to be perfect for the purposes of the project. The result was a whole new kind of textile material that surpasses existing materials on several points and can be recycled again and again. He calls the new material APCT, which stands for all-polyamide composite coated textile, unlike textiles with, for example, PVC coating. The most common method of making a textile material dense is to apply a sealing layer and have it adhere using heat or chemicals, which requires a lot of energy and water. Mostafa Jabbari's solution was to incorporate textile and coating into each other in a process that is neither dependent on heat nor large quantities of water.
The solution—a new solvent
"I dissolved polyamide with a solvent consisting of formic acid and applied it as a thin film onto the polyamide textile. The solution causes the polymer strands to creep into the fabric. When the solvent evaporates, entirely without heat or other chemicals, the polyamide strands in the solution and the textile are entangled in each other and the result is a completely new textile material that is impermeable."
Lab experiment – a polyamide solvent is applied onto a piece of polyamide textile. Credit: University of Borås
However, the solvent he used in the beginning proved to have some challenging properties, such as that it smells bad, is expensive, and is flammable. Therefore, he developed a new concept for the solvent, as well.
"The challenge was to produce a mixture with as little formic acid as possible, but with the right properties to be able to dissolve the polyamide. We did several experiments in which we replaced almost half of the amount of formic acid with urea and calcium chloride, two harmless substances. The result was a clearly more environmentally friendly solvent. However, the process needs to be refined to work industrially," he explains.
New method for matching chemicals
Obtaining the optimal mixture can be done by testing it, but with several chemical substances involved, either pure luck or countless experiments are required to match different substances and proportions to the desired mixtures. Therefore, a computerized method was also introduced to get a reasonable match and thus minimize the need for the number of experiments. This is a method that researchers in other fields may also use when developing or needing to replace or design a solvent mixture profile.
Although the starting point for the Mostafa Jabbaris doctoral project has been to develop a suitable material specifically for textile reactors, with the right properties in terms of insulation, permeability, and flexibility, he sees many other possible applications.
"The new textile could, for example, be used for tents, different types of structural buildings with inflatable elements, or for anything that needs to be lightweight and keep impermeable."
The properties gained are that the new textile material weighs 20 percent less than if it had a PVC coating, it is cheaper to produce, no heat or energy is required, no additional chemicals are needed besides the solvent itself, and the new textile material can be recycled because It consists of a single component.New method cuts out steps in the production of smart and functional textiles
The Romans have been denounced for their reverie in ‘vice’ but their hedonistic approach to love and sexuality should be celebrated. Credit: salajean/Shutterstock
Greek homosexuality has been set upon a pedestal, deemed a worthy and respectable model for romance by philosophers, writers and lovers alike. The reality is, though, that love and sex for the queer community owe more to the ancient Romans. Their approach was grittier, dirtier and sometimes just as romantic. However, it's an outlook on sex and love we are only now coming to embrace.
Ancient Greece's appeal to gay men is much better known.
Pioneering activists such as John Addington Symonds (1840-1893) and George Cecil Ives (1867-1950) turned to Greece as a respectable model. It offered them a legitimizing precedent for elevated and spiritual love between men. They found this through Platonic philosophy and historical and mythical examples of devoted lovers.
Greek love is celebrated in their work for "sublimity" and "aesthetic" appreciation of male beauty. However, when describing Roman love and erotic practices words such as "gross," "obscene," and "lust" abound. To them, Roman homosexuality was not expressed with romantic love, but with riotous orgies. It is often linked to the notorious emperor Nero. A hedonistic ruler who married both women and men. A man who is believed to have enjoyed penetrating as much as he enjoyed being penetrated by his well-endowed husband.
These authors also criticize the license of Roman writers including Petronius, whose novel the Satyricon became a byword for Roman decadence. Catullus, in whose work tender love verses for women and boys are found alongside shocking sexual imagery. Also frequently attacked for obscenity, were the poets Juvenal and Martial.
Rome embraced
Demonising Roman vice was politically convenient. Doing so highlighted the virtue of Greek homosexuality and bestowed a similar virtuous sheen upon those who denounced Rome's debauched ways. But for those who did not feel the need to apologize for their desires, the Romans provided a positive model.
While Greek homosexuality was rather bloodless—used to demonstrate that love between two men could be respectable—Rome is able to encompass a much queerer and more varied set of erotic possibilities.
When Rome is embraced, love and sex need not be mutually exclusive. This can be seen in the anonymous and clandestinely circulated 1893 pornographic novel Teleny.
Nods to Rome in the novel include sex scenes with language recalling the imagery found in the works of Catullus and Martial. For instance, at an orgy, cross-dressing men are titillated by paintings that recreate sexually explicit Roman murals. There are also passages on Rome's obsession with huge penises, reflected in its worship of the god Priapus, who was famed for his enormous member.
Teleny even suggests that love, and not just sex, between men can be influenced by Rome. The devoted couple who form the novel's emotional heart are repeatedly presented as the emperor Hadrian and his beloved, Antinoüs. The novel's use of this Roman pair even suggests that love between two men can survive beyond death, recalling Hadrian's mourning for his lover after his untimely demise, and immortalizing of Antinoüs throughout the Empire.
The book is sometimes attributed to Oscar Wilde. However, Wilde publicly defended himself against charges of being a "sodomite" by appealing to the idealized vision of Greek love. Yet in private, he toyed with the pleasingly decadent model offered by Rome and the emperor Nero.
There, describing a sexual encounter with a male lover, he slips from English into Latin. In writing about sex using the very language of ancient Rome, Symonds was participating in a long modern tradition. Latin has been used as a private language in which upper-class men could talk between themselves about sex, safe in the knowledge that their wives or servants would not be able to understand.
Rome has appealed to far fewer LGBTQ+ women than men, precisely because it is mostly a male elite who have had access to a classical education. Yet Rome has played a role in love between women for a few privileged and extraordinary individuals.
Long before the Victorian era, Anne Lister (1791-1840) of Shibden Hall, and of Gentleman Jack fame, turned to Rome for a variety of erotic possibilities.
Lister had studied Greek and Latin with a private tutor. She claimed that Greek was her favorite language, yet Roman examples appealed to her when it came to matters of the heart—and other parts of the body. She flirtingly referred to Ovid's "Metamorphoses" to sound out whether a new female friend was aware of the queer possibilities of antiquity, masturbated to the poet Juvenal (who had surely never imagined such a use for his satires savagely condemning sex between women), and translated Martial for her lover Marianna, before jumping into bed with her—presumably not to sleep.
From a broad range of erotic possibilities and a private sexual language, to models for romantic relationships, Rome has had an important impact on queer lives and loves. Yes, it is much more down and dirty but in many ways it is much more realistic. As such, we should place it on an equal pedestal to that of pretty Greek queerness and celebrate the pleasure and pain of Roman love and sex.
New process for preserving lumber could offer advantages over pressure treatingby Georgia Institute of Technology GEORGIA IS HOME TO AMERICA'S PAPER INDUSTRY
Treated and untreated pieces of lumber submerged in water. The lumber on the left has been treated using atomic layer deposition. It resists absorbing water even when submerged. On the right is untreated lumber shown for comparison. It readily soaks up water, causing a color change within seconds. Credit: Allison Carter, Georgia Tech
Pressure treating—which involves putting lumber inside a pressurized watertight tank and forcing chemicals into the boards—has been used for more than a century to help stave off the fungus that causes wood rot in wet environments.
Now researchers at the Georgia Institute of Technology have developed a new method that could one day replace conventional pressure treating as a way to make lumber not only fungal-resistant but also nearly impervious to water—and more thermally insulating.
The new method, which will be reported February 13 in the journal Langmuir and jointly sponsored by the Department of Defense, the Gulf Research Program, and the Westendorf Undergraduate Research Fund, involves applying a protective coating of metal oxide that is only a few atoms thick throughout the entire cellular structure of the wood.
This process, known as atomic layer deposition, is already frequently used in manufacturing microelectronics for computers and cell phones but now is being explored for new applications in commodity products such as wood. Like pressure treatments, the process is performed in an airtight chamber, but in this case the chamber is at low pressures to help the gas molecules permeate the entire wood structure.
"It was really important that this coating be applied throughout the interior of the wood and not just on the surface," said Mark Losego, an assistant professor in the School of Materials Science and Engineering. "Wood has pores that are about the width of a human hair or a little smaller, and we used these holes as our pathways for the gases to travel throughout the wood's structure."
Pressure treating - which involves putting lumber inside a pressurized watertight tank and forcing chemicals into the boards - has been used for more than a century to help stave off the fungus that causes wood rot in wet environments. Now researchers at the Georgia Institute of Technology have developed a new method that could one day replace conventional pressure treating as a way to make lumber not only fungal-resistant but also nearly impervious to water - and more thermally insulating. Credit: Georgia Tech
As the gas molecules travel down those pathways, they react with the pore's surfaces to deposit a conformal, atomic-scale coating of metal oxide throughout the interior of the wood. The result is wood that sheds water off its surface and resists absorbing water even when submerged.
In their experiments, the researchers took finished pine 2x4s and cut them into one-inch pieces. They then tested infusing the lumber with three different kinds of metal oxides: titanium oxide, aluminum oxide and zinc oxide. With each, they compared the water absorption after holding the lumber under water for a period of time. Of the three, titanium oxide performed the best by helping the wood absorb the least amount of water. By comparison, untreated lumber absorbed three times as much water.
"Of the three chemistries that we tried, titanium oxide proved the most effective at creating the hydrophobic barrier," said Shawn Gregory, a graduate student at Georgia Tech and lead author on the paper. "We hypothesize that this is likely because of how the precursor chemicals for titanium dioxide react less readily with the pore surfaces and therefore have an easier time penetrating deep within the pores of the wood."
Losego said that the same phenomena exist in atomic layer deposition processes used for microelectronic devices.
"These same titanium oxide precursor chemistries are known to better penetrate and conformally coat complex nanostructures in microelectronics just like we see in the wood," Losego said. "These commonalities in understanding fundamental physical phenomena—even in what appear to be very different systems—is what makes science so elegant and powerful."
From left to right, Shannon Yee, an associate professor in the Woodruff School of Mechanical Engineering, Shawn Gregory, a graduate student at Georgia Tech, and Mark Losego, an assistant professor in the School of Materials Science and Engineering, demonstrate the water repellent qualities of a new lumber treatment process based upon atomic layer deposition. Credit: Allison Carter, Georgia Tech
In addition to being hydrophobic, lumber treated with the new vapor process also resists the mold that eventually leads to rot.
"Interestingly, when we left these blocks sit in a humid environment for several months, we noticed that the titanium oxide treated blocks were much more resistant to mold growth than the untreated lumber," Gregory added. "We suspect that this has something to do with its hydrophobic nature, although there could be other chemical effects associated with the new treatment process that could also be responsible. That's something we would want to investigate in future research."
Yet another benefit of the new process: vapor-treated wood was far less thermally conductive compared to untreated wood.
"A lot of attention is paid in home building to insulating the cavities between the structural components of a home, but a massive amount of the thermal losses are caused by the wood studs themselves," said Shannon Yee, an associate professor in the George W. Woodruff School of Mechanical Engineering and a co-author on the paper with expertise in thermal systems. "Lumber treated with this new process can be up to 30 percent less conductive, which could translate to a savings of as much as 2 million BTUs of energy per dwelling per year."
Explore furtherTaking the carbon out of construction with engineered wood More information: Shawn A. Gregory, Connor P. McGettigan, Emily K. McGuinness, David Misha Rodin, Shannon K. Yee, and Mark D. Losego, "Single-Cycle Atomic Layer Deposition (1cy-ALD) on Bulk Wood Lumber for Managing Moisture Content, Mold Growth, and Thermal Conductivity," Langmuir, February 2020. dx.doi.org/10.1021/acs.langmuir.9b03273 Journal information: Langmuir
Mass migrations of people in Guatemala and Honduras - partially driven by political instability, but also driven by drought-related conditions and changes in seasonality are creating enormous problems for agricultural production and feeding a growing population. Credit: Keith Prufer, UNM
Research by an international team of scientists led by University of New Mexico Professor Yemane Asmerom suggests contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America, and aggravating current trends of social unrest and mass migration.
Positioned near the equator where the trade winds of the northern and southern hemisphere converge, the ITCZ is the world's most important rainfall belt affecting the livelihood of billions of people around the globe. Globally, seasonal shifts in the location of the ITCZ across the equator dictate the initiation and duration of the tropical rainy season. The behavior of the ITCZ in response to the warming of the Earth is of vital scientific and societal interest.
Previous work based on limited data suggested a southward migration of the ITCZ in response to global cooling, such as during the Little Ice Age a few hundred years ago. In contrast, modeling and limited observational data seemed to suggest the ITCZ expands and contracts in response to cooling and warming. Which of these scenarios is correct has a huge implication for understanding rainfall variability and its economic and social impacts across the tropics. In order to resolve these seemingly contradictory alternatives the authors undertook this paleoclimate reconstruction study from the margin of the ITCZ and combined that with existing data from across the full annual north-south excursion of the ITCZ.
The study titled, "Intertropical Convergence Zone Variability in the Neotropics During the Common Era," was published today in Science Advances. In addition to UNM, the research also includes scientists from the University of Durham (UK), Northumbria University (UK) and the University of California, Santa Barbara.
"Much of our understanding of ITCZ variability was based on records from South America, especially the Cariaco Basin (Venezuela), which was the gold standard," explained Asmerom. "But these studies were only able to present half of the picture. As a result, they suggested southward movement of the mean position of the ITCZ during cool periods of Earth, such as during the Little Ice Age, and by implication it shifts northward during warm periods.
"This would imply regions in the northern margin of the ITCZ, such as Central America would get wetter with warming climate. This contradicted modeling results suggesting drying as a consequence of warming."
With two testable hypotheses, Asmerom and his colleagues used 1,600 years of new bimonthly-scale speleothem rainfall reconstruction data from a cave site located at the northern margin of the ITCZ in Central America, coupled with published data from the full transect of the ITCZ excursion in Central America and South America. The combined data elucidate ITCZ variability throughout the Common Era including the warmer Medieval Climate Anomaly and the cooler Little Ice Age. The results of this study are consistent with models suggesting ITCZ expansion and weakening during global periods of cold climate and contraction and intensifying during periods of global warmth.
"Stable isotopic data obtained at Durham University, and trace element data and a precise uranium-series chronology, with an average 7 year uncertainty, obtained at the University of New Mexico, provided us with a nearly bi-monthly record of past climate variability between 400 CE to 2006. This level of resolution is unprecedented for continental climate proxies", said Polyak.
The University of New Mexico research team was led by Professor Yemane Asmerom (3rd from left) and included (l. to r.): Valorie Aquino, Keith Prufer and Victor Polyak. The team found contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America.. Credit: The University of New Mexico
"What we found was that in fact during the Medieval Climate Anomaly Southern Belize was very dry, similar to modern central Mexico. In contrast, during the Little Ice Age cool period, when it should have been dry by the standard old model, it was the wettest interval over the last 2000 years," said Asmerom. "The pattern that emerges when all the data across the full transect of ITCZ excursion is supportive of the expansion-contraction model." The implication of this that regions currently in the margins of the ITCZ are likely to experience aridity with increased warming, consistent with modeling data from Central America. These data have important implications for rainfall-dependent agriculture system on which millions of people depend for food security.
Co-author and UNM Professor of Anthropology Keith Prufer is an environmental archaeologist, who has been conducting research in Belize for 25 years. "In the last five years there have been mass migrations of people in Guatemala and Honduras—partially driven by political instability, but also driven by drought-related conditions and changes in seasonality. This is creating enormous problems for agricultural production and feeding a growing population. There is growing evidence that these changes are a direct consequence of climate change."
"This work highlights the convergence of good science with policy relevancy. It also illustrates the strength of cross-disciplinary collaborative work, in this case international," said Asmerom.
Dinosaur nesting site in Alberta, Canada. Credit: Darla Zelenitsky
From the time that dinosaur fossils were first discovered, these creatures have fascinated scientists and laypeople alike. In the academic world, their remains provide important clues into the prehistoric world; in popular culture, dinosaurs have inspired blockbuster hits, such as Jurassic Park and King Kong.
Now, a research team headed by Professor Hagit Affek at the Hebrew University of Jerusalem's Institute of Earth Sciences has unlocked a mystery that has stymied researchers for decades: How diddinosaursregulate their body temperatures? Were they warm-blooded or cold-blooded?
Affek's study, published today in Science Advances, relies on a novel method to measure historical temperatures. Called clumped isotope geochemistry, this method analyzes chemical bonds among heavy isotopes in calcium carbonate minerals—the main ingredient in egg shells. This allows scientists to calculate both the temperature at which the minerals formed and the body temperature of the mother that laid the egg.
Affek and her team applied this method to fossilized eggs from three distinct dinosaur species along the evolutionary path from reptile to bird and found that their body temperature ranged from 35-40 degrees Celsius. However, this bit of information still did not answer the question as to whether dinosaurs were endothermic or exothermic, meaning, did they generate their own body heat or get warm from the sun and their environment?
"The global climate during the dinosaur era was significantly warmer than it is today. For this reason, measuring only the body temperatures of dinosaurs who lived near the equator wouldn't tell us whether they were endo- or exothermic because their body temperature may simply have been a cold-blooded response to the hot climates they lived in," shared Affek.
Hadrosaur eggshells. Credit: Darla Zelenitsky
To address this issue, her team focused on dinosaurs that lived in high latitudes like Alberta, Canada—far enough north to ensure that their warm body temperatures were the result of an internal, metabolic warming process rather than merely reflecting the climate around them.
To verify their hypothesis, Affek and her team needed to determine the environmental temperature in Alberta back when dinosaurs lived. They accomplished this by applying their isotope method to mollusk shells that lived in Alberta alongside the dinosaurs. Since mollusks are cold-blooded creatures, they reflect the ambient climate of the time. The mollusks' body temperature measured 26°C and showed that the dinosaurs living in Alberta were endothermic; otherwise, they could not have maintained a body temperature of 35-40°C.
As dinosaurs evolved, they moved from lizard-like (cold-blooded) characteristics to avian (warm-blooded) ones. "We believe that this transformation happened very early on in dinosaurs' evolution since the Mayasaura eggs—a lizard-like dinosaur species that we tested—were already able to self-regulate their body temperature, just like their warm-blooded, bird-like cousins, the Torrdons," explained Affek.
The fact that both of these species, located at opposite ends of the dinosaur evolutionary tree, had body temperatures higher than those of their environment means that both had the ability to warm themselves.
Either way, Mother of Dragons, if your baby is showing a fever of 41 degrees, it's time to call the doctor.
