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)
Wednesday, February 19, 2020
Standalone system produces water from the air, even in desert regions
The new system that produces water from the air. Credit: Technion - Israel Institute of Technology
Researchers at the Technion have developed a standalone system that produces water from the air, even in desert regions. The innovative system is capable of providing water to small and isolated communities, without the need to transport water for long distances.
According to estimates by the World Health Organization (WHO), about 13% of the world's population will suffer from insufficient availability of drinking water by 2025. For this reason, access to freshwater is one of the 17 Sustainable Development Goals (SDGs) adopted by the United Nations in 2015. This goal was the motivation for developing a standalone system for producing water from the air.
The technology was developed by Professor David Broday and Professor Eran Friedler from the Environmental, Water and Agricultural Engineering Division of the Technion Faculty of Civil and Environmental Engineering, and the Stephen and Nancy Grand Water Research Institute (GWRI). It is the first technology of its kind in the world: an energy-efficient system for producing clean water from the air. Unlike the existing technology, the Technion researchers' system is based on a two-stage cyclic process: separation of moisture from the air by absorption using a highly concentrated saline solution, and separation of the moisture from the desiccant under and condensing the vapor under sub-atmospheric pressure conditions.
Credit: Technion - Israel Institute of Technology
"Besides being energy efficient, the new technology offers an additional advantage: as part of the process the water undergoes also pollutant removal processes," said Prof. Broday. "Our technology turns water into a commodity as it enables water to be produced anywhere in the world, without being dependent upon existing sources of liquid water. The prototype we have built demonstrates that the system works as expected and we currently work toward turning it into a commercial product."
"Existing technologies work simply as "reverse" air conditioners, by cooling the whole air mass entering the system in order to condense the moisture," said Prof. Friedler. "This 'direct cooling' approach is energetically inefficient, since such systems waste much of their energy requirements on cooling about 97% of the air volume, which is non-condensable. The new technology involves cooling of only the moisture that has been extracted from the air, significantly reducing the amount of energy required to produce water."
"We are not competing with desalination," explained Prof. Broday. "Israel is a developed nation situated near the sea and can supply all its water needs through desalination systems. Among other reasons, this is because Israel is a relatively small country and a significant portion of the population lives along the coast, such that water does not need to be transported over long distances. In contrast, transporting desalinated water to communities situated far from the coast is very expensive due to the need for extremely long pipelines. Herein lies the advantages of the new technology." The system is particularly relevant for small and isolated communities that are located far from fresh- or salty- water sources, as it can produce water where it is most needed.
According to Prof. Friedler, "in addition to being an essential component of life, water also influences other important aspects, among them individual and community health and even the empowerment of women. In many places, young girls do not attend school because they are busy providing water for the family. Even as adults, women devote hours to transporting water. Furthermore, access to water is a central factor in bloody confrontations in arid regions nowadays, and constitutes one of the foremost motives for immigration. In such conflict zones, the risk of children dying from polluted water is 20 times higher than dying due to violent acts."
Can magic mushrooms and LSD treat depression and anxiety? Scientists are optimistic.
by Bethany Ao
Credit: CC0 Public Domain
When Marc Morgan tried lysergic acid diethylamide, better known as acid or LSD, for the first time as a teenager, he noticed that he could emotionally disconnect from traumatic memories of the sexual abuse he had suffered as a child.
"It allowed me to dissociate from the sharp pain that a lot of these memories can bring up, which caused me to shy away from processing them," said Morgan, who has post-traumatic stress disorder (PTSD) as a result of the abuse. "I was able to confront the topic in a more analytical way that felt healthier."
Years later, Morgan learned about microdosing—taking tiny portions of psychedelic substances, as little as a twentieth of a recreational dose, to get positive effects, like more focus and emotional balance, without negatives like hallucinations and disorientation. He realized that taking small doses allowed him to process his emotions without the stronger, visual effects and looping thoughts.
"It's basically like taking a cup of coffee," said Morgan, now 30. He said that he takes a full dose once or twice a year, and microdoses about four times a year. "You're just able to be a little more free and a little more honest with your emotions without breaking down. There's more of a mental clarity."
Morgan, who has lived in Philadelphia for the past decade, is part of a group of people who use both full doses and microdoses of psychedelic substances to process trauma, and better deal with depression. For some, it's because conventional antidepressants haven't worked for them. Others choose psychedelics because it's a more affordable option than therapy or medication.
"For people interested in a treatment who can't get into a trial, this is not the only thing out there," said Matthew Johnson, an associate professor of psychiatry and behavioral sciences at Johns Hopkins University who has studied psychedelics for over 15 years. "It's one promising thing, and it's important for people to stay in treatment."
In recent months, the use of psychedelics for treatment-resistant depression, anxiety and PTSD—meaning patients do not respond to medication or therapy—has become a hot topic in the mental health field. The FDA approved a nasal spray for treatment-resistant depression (TRD) last March, which uses a derivative of the hallucinogenic ketamine called esketamine. It is the first new antidepressant in decades. (It's currently offered at a handful of clinics in the Philadelphia area.)
In November, the FDA gave psilocybin, a hallucinogenic compound found in magic mushrooms, its second "breakthrough therapy" designation in just over a year. The designation fast-tracks the development and review of drugs.
In a 2017 study of psilocybin and depression, researchers at Imperial College London gave psilocybin therapy to 20 patients with treatment-resistant depression, who reported benefits as long as five weeks after treatment. The study found that psilocybin decreased activity in the amygdala, which processes emotions like fear and anxiety.
"We know that when someone is on a therapeutic dose of a psychedelic, there's a dramatic increase in communication across brain areas," Johnson said. "My theory is that what we're seeing with psychedelic therapy is more like what we normally associate with talk therapy. Psychedelic therapy prompts a therapeutic process, and people learn something by transcending their sense of self and getting out of their own way."
Much less is known about the science behind microdosing psychedelic substances, but a 2019 study by researchers at the University of California-Davis found that the practice can provide relief for symptoms of depression and anxiety in rats.
Additionally, a 2019 survey of more than 1,000 people from across the world who microdosed on LSD found that repeated microdoses were followed by "improvements in negative moods, especially depression" as well as increased positive moods and energy levels.
"There really hasn't been substantiation of the claimed benefits of so-called microdoses," Johnson said. "That's not to say the claimed benefits aren't possible."
The benefits people feel from microdosing might be from a combination of a strong placebo effect and some possible benefit from "tinkering with the serotonin system," Johnson said. But he's open to the potential benefits of microdosing, particularly for depression.
As a result of their research on how psychedelics can be used to help smokers and cancer patients, Johnson and others at Johns Hopkins have suggested that psilocybin's FDA classification should be changed from Schedule I, which means that it has no known medical benefit, to Schedule IV, similar to prescription drugs.
Victor Pablo Acero, a 24-year-old bioengineering doctoral candidate and executive director of the Penn Society for Psychedelic Science, said that accepting both full doses and microdoses as mental health treatments is an important step in destigmatizing the substances.
"Having a mystical experience is correlated with actually getting more clinical effects," Acero said. "Microdosing doesn't recapitulate the mystical experience or ego death. Also psychedelic use ... does not magically heal you, you have to put in work and effort to integrate your experience."
Acero said that he became interested in psychedelics once he began reading research papers about how the substances can be used in clinical settings. But he said that research in this area is still lacking.
"Funding is nonexistent," Acero said. "Scientists are having to argue that they need funding to study the medical purposes of a substance that's classified as having no medical purposes."
Most people suffering from treatment-resistant depression, anxiety or PTSD won't be able to access the new treatments for at least a few years, as research groups run clinical trials. The trials have a limited number of spaces ? - the Usona Institute, a nonprofit medical research group, recruited just 80 participants for a study that's part of their Phase 2 clinical trial for psilocybin. Similarly, LSD is being evaluated in a Phase 2 clinical trial as a treatment for depression in Switzerland. MDMA, better known as ecstasy or molly, is currently in a Phase 3 large-scale clinical trial for PTSD. Upon FDA approval, the SoundMind Center will open in Cedar Park, offering MDMA-assisted psychotherapy to populations with higher rates of PTSD.
While patients wait, self-medication without the aid of a therapist or medical professional is much more common, although it is not recommended. Johnson said that there are risks to psychedelic therapy for people with existing psychotic disorders, like schizophrenia.
"Even if this stuff is approved, it's not going to work for everyone," Johnson said.
Aysha Ali, who struggles with depression and anxiety, began using full doses and microdoses of magic mushrooms about two years ago. Ali, 21, said antidepressants caused side effects like appetite loss, decreased libido and nausea. She also found that mushrooms are more accessible and cheaper for her.
"It's definitely easier to go to bed at night," said Ali, who lives in Wilmington, Del. and works in King of Prussia. "I'm a little more focused, and I feel like I can smile and giggle in the moment. I can feel myself going through my day a little bit better, and the days after feel so much better."
She said that it refreshes her brain and allows her to wake up with a positive attitude.
"It helps me see that I'm not going to be stuck where I am," Ali said. "It's not a cure for everything, but the scientific information we're getting now is helping people get out of this mindset of, 'This is bad.'"
Mike Allebach, a photographer who lives in Montgomery County, first learned about magic mushrooms for mental health through a New York Times article last year.
"It didn't really quite match up with my understanding of mushrooms," said Allebach, 37.
Allebach, who was struggling with depression when he read the article, said that he later tried magic mushrooms in California, where psilocybin mushrooms are decriminalized in Oakland and Santa Cruz. The trip brought him out of his depression. Since coming home, Allebach uses breath work and meditation to maintain his mental health.
"As a society, we're in a place where the new rich is feeling calm and having peace. And if antidepressants don't work for someone, this could be great for someone who wants to be happy again and work on themselves," he said.
The old story of a farmer trying to get a stubborn mule to pull a wagon by dangling a carrot in front of its nose, or hitting its rump with a stick, may not seem to have much to do with the practice of medicine.
But a new study suggests that when it comes to making the best use of health care dollars, it will take a combination of carrots and sticks to move things forward.
The study looks at the effects of two initiatives that aimed to reduce the use of two blood tests that experts consider "low value" for most patients: Routine vitamin D tests, and an unnecessary thyroid test for tracking thyroid hormone levels.
After an organization that advises the health care system in Ontario, Canada reported in 2010 that population-based Vitamin D screening does not improve outcomes, the province's health plan for all residents declared it wouldn't pay for low-value vitamin D tests.
Soon after, the rate of testing dropped nearly 93 percent, the study shows. Patients who had a condition or medication that might lower their vitamin D levels could still get tested.
But in the U.S., where no such payment change took place, 2.6 million unnecessary vitamin D screening tests happened in just one year, according to the researchers from the University of Michigan, University of Toronto and VA Ann Arbor Healthcare System who published the new findings in JAMA Internal Medicine.
A few years later, as part of an education campaign called Choosing Wisely, physician professional societies issued recommendations on when not to use Vitamin D and T3 testing. And while use of the test in Ontario dropped an additional 4.5%, the use in U.S. patients covered by Veterans Health benefits or commercial insurance dropped about 14%.
"Our study found small reductions in the use of unnecessary vitamin D screenings in response to recommendations from the Choosing Wisely campaign, but much greater reductions in Ontario when recommendations were complemented by policy change," says Eve Kerr, M.D., M.P.H., senior author of the new paper and a professor in the U-M Department of Internal Medicine. "The biggest lesson is that while recommendations alone can work to reduce low value care, recommendations have greater impact when they are reinforced by changes to policy and practice."
Improving value
Kerr heads a program at the U-M Institute for Healthcare Policy and Innovation called the Michigan Program on Value Enhancement. She and her colleagues used the same Choosing Wisely guideline to build an alert for clinicians who had ordered a vitamin D test of low potential value into the electronic health record at Michigan Medicine, U-M's academic medical center.
In 2018, they reported that this guideline-based "carrot" had led to a positive and sustained change in orders for low-value vitamin D tests.
James Henderson, Ph.D., the first author of the new paper, assistant director of MPrOVE and a data science consultant at U-M's Consulting for Statistics, Computing and Analytics Research unit, notes that the new paper's findings show that Choosing Wisely recommendations for T3 testing did not appear to have had the desired impact.
T3 testing, which is no longer recommended for patients with known thyroid issues because a test called TSH is more accurate, did not decline in either the U.S. or Canada after Choosing Wisely guidelines were issued. In fact, in the study population of U.S. patients with private insurance, the rate of testing actually went up slightly.
Handle with care
Kerr, Henderson and their colleagues from IHPI and the VA Center for Clinical Management Research note that policy decisions for low-value care—including payment changes—must be made with care, to avoid problems with access to that type of care for patients who could benefit.
For instance, the Ontario payment change exempted patients who have bone or digestive disorders that can change vitamin D levels, and patients who take certain medications that can change vitamin D absorption from food and supplements.
"Payment policies are not the only effective means for reducing low-value care," says Kerr. "Indeed, sometimes restricting payment may be too blunt an approach and could lead to underuse."
She adds, "Other effective policies that can be coupled with recommendations include population based education programs, communication approaches to help patients and physicians make more patient-centered decisions, decision support for doctors about low-value care, and most importantly, culture change initiatives that emphasize the responsibility of health care institutions, clinicians, and patients to provide and seek high-value, evidence-based care while avoiding low-value services."
More information: James Henderson et al, Comparison of Payment Changes and Choosing Wisely Recommendations for Use of Low-Value Laboratory Tests in the United States and Canada, JAMA Internal Medicine (2020). DOI: 10.1001/jamainternmed.2019.7143
Simple, fuel-efficient rocket engine could enable cheaper, lighter spacecraft
The researchers first developed an experimental rotating detonation engine (shown here) where they could control different parameters, such as the size of the gap between the cylinders. The feed lines (right) direct the propellant flow into the engine. On the inside, there is another cylinder concentric to the outside piece. Sensors sticking out of the top of the engine (left) measure pressure along the length of the cylinder. The camera would be on the left-hand side, looking from the back end of the engine. Credit: James Koch/University of Washington
It takes a lot of fuel to launch something into space. Sending NASA's Space Shuttle into orbit required more than 3.5 million pounds of fuel, which is about 15 times heavier than a blue whale.
But a new type ofengine—called a rotating detonation engine—promises to make rockets not only more fuel-efficient but also more lightweight and less complicated to construct. There's just one problem: Right now this engine is too unpredictable to be used in an actual rocket.
Researchers at the University of Washington have developed a mathematical model that describes how these engines work. With this information, engineers can, for the first time, develop tests to improve these engines and make them more stable. The team published these findings Jan. 10 in Physical Review E.
"The rotating detonation engine field is still in its infancy. We have tons of data about these engines, but we don't understand what is going on," said lead author James Koch, a UW doctoral student in aeronautics and astronautics. "I tried to recast our results by looking at pattern formations instead of asking an engineering question—such as how to get the highest performing engine—and then boom, it turned out that it works."
A conventional rocket engine works by burning propellant and then pushing it out of the back of the engine to create thrust.
To start the reaction, propellant flows in the gap between the cylinders, and, after ignition, the rapid heat release forms a shock wave (starts at 11 seconds). After this start-up phase, a number of stable combustion pulses form that continue to consume available propellant. Credit: James Koch/University of Washington
"A rotating detonation engine takes a different approach to how it combusts propellant," Koch said. "It's made of concentric cylinders. Propellant flows in the gap between the cylinders, and, after ignition, the rapid heat release forms a shock wave, a strong pulse of gas with significantly higher pressure and temperature that is moving faster than the speed of sound.
"This combustion process is literally a detonation—an explosion—but behind this initial start-up phase, we see a number of stable combustion pulses form that continue to consume available propellant. This produces high pressure and temperature that drives exhaust out the back of the engine at high speeds, which can generate thrust."
Conventional engines use a lot of machinery to direct and control the combustion reaction so that it generates the work needed to propel the engine. But in a rotating detonation engine, the shock wave naturally does everything without needing additional help from engine parts.
"The combustion-driven shocks naturally compress the flow as they travel around the combustion chamber," Koch said. "The downside of that is that these detonations have a mind of their own. Once you detonate something, it just goes. It's so violent."
To try to be able to describe how these engines work, the researchers first developed an experimental rotating detonation engine where they could control different parameters, such as the size of the gap between the cylinders. Then they recorded the combustion processes with a high-speed camera. Each experiment took only 0.5 seconds to complete, but the researchers recorded these experiments at 240,000 frames per second so they could see what was happening in slow motion.
After the initial shock wave, stable pulses of combustion continue to consume available propellant. Previously researchers didn't understand how a specific number of pulses formed and why they can sometimes merge into one pulse, but this mathematical model developed by University of Washington researchers can help explain the underlying physics. Credit: Koch et al./Physical Review E
From there, the researchers developed a mathematical model to mimic what they saw in the videos.
"This is the only model in the literature currently capable of describing the diverse and complex dynamics of these rotating detonation engines that we observe in experiments," said co-author J. Nathan Kutz, a UW professor of applied mathematics.
The model allowed the researchers to determine for the first time whether an engine of this type would be stable or unstable. It also allowed them to assess how well a specific engine was performing.
"This new approach is different from conventional wisdom in the field, and its broad applications and new insights were a complete surprise to me," said co-author Carl Knowlen, a UW research associate professor in aeronautics and astronautics.
Right now the model is not quite ready for engineers to use.
"My goal here was solely to reproduce the behavior of the pulses we saw—to make sure that the model output is similar to our experimental results," Koch said. "I have identified the dominant physics and how they interplay. Now I can take what I've done here and make it quantitative. From there we can talk about how to make a better engine."
More information: James Koch et al, Mode-locked rotating detonation waves: Experiments and a model equation, Physical Review E (2020). DOI: 10.1103/PhysRevE.101.013106
Fifty years of data show new changes in bird migration
Black-throated Blue Warblers have shifted the timing of their spring and fall migrations over the past fifty years. Credit: Kyle Horton
A growing body of research shows that birds' spring migration has been getting earlier and earlier in recent decades. New research from The Auk: Ornithological Advances on Black-throated Blue Warblers, a common songbird that migrates from Canada and the eastern U.S. to Central America and back every year, uses fifty years of bird-banding data to add another piece to the puzzle, showing that little-studied fall migration patterns have been shifting over time as well.
Loyola Marymount University's Kristen Covino and her colleagues used data housed at the USGS Bird Banding Laboratory on migrating Black-throated Blue Warblers between 1965 and 2015. Across the United States, researchers working with this program safely capture migrating birds, collect data on them, and fit them with metal leg bands with unique codes that allow them to be identified if they're captured again. Analyzing almost 150,000 individual records, Covino and her colleagues found that the timing of the birds' spring migration has advanced over the last fifty years, with early migrants passing through banding sites approximately one day earlier each decade. Crucially, their data also covered fall migration, which has been less well-studied, and found that while the timing of the peak of fall migration hasn't changed, fall migration takes longer today than it did fifty years ago.
The North American Bird Banding Program is one of the most expansive historical datasets on migratory birds, including records for over 38 million songbirds banded since 1960. "My coauthor Sara Morris and I were already working together on another paper on Blackpoll Warblers using data we'd requested from banding stations across North America. We wanted to take a similar large-scale approach for this study, but we wanted to demonstrate that we could do this approach with data that is completely available from the Bird Banding Lab," says Covino. "We selected Black-throated Blue Warblers because it's relatively straightforward to determine their age and sex, which means that the data this species generates are both accurate and powerful."
Researchers handle female (left) and male (right) Black-throated Blue Warblers. Credit: Sara Morris
Although the researchers emphasize that their findings can't be explicitly linked to climate change without incorporating climate or environmental data, they believe similar methods could be useful for tracking the effects of climate change on birds. "The protraction of fall migration means that the season is getting longer overall, but it could also mean that the breeding season may be shifting, ending earlier for some individuals but later for others. To determine what this means in the context of breeding season shifts in timing, additional studies that incorporate both arrival on the breeding grounds and, importantly, departure from them are needed," says Covino. "More studies of these patterns of fall migration timing and, even more so, both spring and fall migration timing across years are needed to gain the complete picture of how species are changing migration timing."
Historical wood panel paintings with developed craquelure patterns—networks of fine cracks in the paint- are significantly less vulnerable to environmental variations than previously assumed, according to a study in the open access journal Heritage Science. The findings offer a potential explanation as to why heavily cracked historical paintings remain stable in environments far from 'ideal' museum conditions.
Painted wood is among the most precious and frequently exhibited category of heritage objects and among the most vulnerable to relative humidity and temperature fluctuations.
Lukasz Bratasz, the corresponding author said: "The current environmental standards for the display of painted wood allow for only moderate variations of relative humidity. The safe range was determined based on laboratory testing of when cracks start to form in new, undamaged material. However, this does not reflect the physical reality of paintings as they age and complex craquelure patterns form. Our research more accurately reflects that physical reality, accounting for changes in the susceptibility to environmental stresses as paintings age."
To investigate the development of cracks in gesso layers subject to different environmental conditions over time, the authors designed specimens of two wooden panels, which they joined with gessoes prepared according to traditional recipes. The specimens were stored at 25°C and relative humidity of 30, 50, 75 and 90% for two weeks before being subjected to splitting test, which measure how resistant gessoes are to cracking.
Using computer tomography to scan historic samples of panel painting, the authors determined the size of existing flaws in the gesso at which new cracks initiate. Those measurements were then used in a computer model of a panel painting to simulate further crack formation. Factoring in the elasticity of the materials and moisture expansion of wood, the authors found that the stress on the gesso decreased as the number of cracks increased over time.
Lukasz Bratasz said: "Stress on the gesso occurs in the areas between cracks. The larger these areas are, the more easily cracks will form. As cracks multiply and the spaces between them become smaller, stress decreases up to a point where, finally, no new cracks will form."
The authors caution that their conclusions are valid for paintings with 'opened' cracks. If cracks are filled in during conservation treatment or varnishing, the vulnerability of a painting to the environment may increase.
Lukasz Bratasz said: "Our findings offer a potential explanation as to why historical panel paintings with developed craquelure patterns remain stable, even if the environmental conditions they are stored in are far from ideal. We hope that this knowledge may contribute to development and acceptance of more moderate-cost climate control strategies in historic buildings and museums, especially ones that may have limited potential for tighter climate control."
More information: Fracture saturation in paintings makes them less vulnerable to environmental variations in museums Bratasz et al. Heritage Science 2020 DOI: 10.1186/s40494-020-0352-0
Eliminating viruses in our food with cranberries and citrus fruit
by Institut national de la recherche scientifique
A norovirus cell culture. Credit: Monique Lacroix, INRS
Fresh produce is a major vehicle for noroviruses, a group of viruses that are the most common cause of gastroenteritis in developed countries. However, the viruses are quite resistant to cold pasteurization treatments such as irradiation, which are used to destroy bacteria, moulds, parasites, and insects. The irradiation process uses gamma rays or X-rays to destroy these viruses but at the dose needed to eliminate them, it can affect the physicochemical properties of fresh produce.
Professor Monique Lacroix, a researcher at Institut National de la Recherche Scientifique (INRS), has developed an edible coating based oncranberry juiceand citrus extract that makes noroviruses more sensitive to gammairradiation, making it possible to eliminate them while preserving the quality of food, all without risk to consumers.
A fruit extract spray
The idea is to spray fresh produce such as lettuce or strawberries and then treat it with cold pasteurization such as irradiation. The organic acids and polyphenols in cranberry juice and citrus extract would alter the viral protein and help inhibit its activity.
"Noroviruses usually require an irradiation dose of three kilograys (kGy), but we have shown that the treatment time is reduced by half with this fruit mixture spray, which acts as a natural antimicrobial. Using these natural antimicrobials prevents cell breakdown or brown discolouration," reports Monique Lacroix, lead author on the study whose results were published online on February 12 in the Journal of Applied Microbiology.
Professor Lacroix's team is the first to test the cranberry juice and citrus extract mixture in a combined treatment. "Both the juice and extract have the ability to remove noroviruses when used alone, but when combined with cold pasteurization in the same treatment, the fruit concentrations required are significantly lower," says the food science expert.
Norovirus Contamination
Norovirus contamination can occur before and after harvest. Contaminated water runoff from fields can bring in fecal matter. Food can be contaminated by infected people who handle it.
"Unlike bacteria, noroviruses do not multiply on food. They are deposited there and remain there until a human being is infected," says Alexandra Gobeil, first author of the study and a recent master's graduate in Applied Microbiology at INRS.
Monique Lacroix and her team have tested the coating on lettuce, one of the most fragile vegetables in terms of preservation. She hopes to eventually develop a partnership with the food industry to test combinations of treatments involving natural fruit extracts and cold pasteurization (e.g., UV-C, X-ray, gamma ray, or ozonation) on a commercial scale.
More information: A. Gobeil et al, Radiosensitivity increase in FCV‐F9 virus using combined treatments with natural antimicrobials and γ‐irradiation, Journal of Applied Microbiology (2020). DOI: 10.1111/jam.14596
Study of stone-age engravings suggests they were created with aesthetic intention
by Bob Yirka , Phys.org
Credit: CC0 Public Domain
A team of researchers from Denmark, Australia and South Africa has found evidence that suggests stone-age etchings found at two sites in South Africa were created with aesthetic intention and that they evolved over time. In their paper published in Proceedings of the National Academy of Sciences, the group describes experiments they carried out with volunteers looking at reproductions of stone-age engravings and what they learned from them.
Back in 1973, researchers found ostrich eggshell water containers with images etched onto them in the Diepkloof Rock Shelter in western South Africa. Subsequent testing showed the containers to be from approximately 60,000 years ago. Not far away, archaeologists began excavating Blombos Cave in 1991, and during that work, discovered engraved ochre and bones. They were dated to between 100,000 and 70,000 years ago. Notably, the etchings at both sites were made over very long periods of time, allowing researchers to study their evolution. As time passed, thehuman brainbecame more sophisticated, allowing humans to express themselves in more tangible form through etchings. In this new effort, the researchers created drawings of the etchings found in both locations and studied them by showing them to volunteers.
In all, the researchers carried out five experiments designed to test the sophistication of the stone-age drawings. The first involved showing volunteers a drawing in one eye and a flickering pattern in the other eye—the researchers timed how long it took the volunteers to identify patterns in the drawings. The images created more recently were more quickly identified as such.
Another test involved showing volunteers two drawings and asking them which they thought was more likely made intentionally—again, those made more recently were identified as likely being intentional.
A third test involved showing volunteers a drawing for just three seconds and then asking them to reproduce it on a piece of paper. Once again, the volunteers were better able to reproduce those images that were created most recently. The fourth test involved asking the volunteers to guess which of two drawings they were shown came from the same site—and once again, they were more accurate when looking at more recently created images. The final test involved asking the volunteers which of two drawings they thought were created more recently; they chose those that had been created more recently. The researchers suggest that the volunteer answers indicated that the engravings were created with aesthetic intention, and clearly evolved in sophistication over time.
View of Takarkori shelter from the west. Credit: Savino di Lernia, 2020
Catfish and tilapia make up many of the animal remains uncovered in the Saharan environment of the Takarkori rock shelter in southwestern Libya, according to a study published February 19, 2020 in the open-access journal PLOS ONE by Wim Van Neer from the the Natural History Museum in Belgium, Belgium and Savino di Lernia, Sapienza University of Rome, Italy, and colleagues.
Today, the Saharan Tadrart Acacus mountains are windy, hot, and hyperarid; however, the fossil record shows that for much of the early and middle Holocene (10,200 to 4650 years BP), this region was humid and rich in water as well as life, with evidence of multiple human settlements and diverse fauna.
Rock shelters within the Tadrart Acacus preserve not only significant floral and faunal remains, but also significant cultural artifacts and rock art due to early Holocene occupation of these shelters. In this study, the authors worked with the Libyan Department of Antiquities in excavating parts of the Takarkori rock shelter to identify and date animal remains found at this site and investigate shifts in the abundance and type of these animal remains over time.
Fish remains made up almost 80 percent of the entire find overall, which numbered 17,551 faunal remains total (19 percent of these were mammal remains, with bird, reptile, mollusc, and amphibian remains the last 1.3 percent). All of the fish and most of the other remains were determined to be human food refuse, due to cut marks and traces of burning—the two fish genera at Takarkori were identified as catfish and tilapia.
Based on the relative dates for these remains, the amount of fish decreased over time (from 90 percent of all remains 10,200-8000 years BP versus only 40 percent of all remains 5900-4650 years BP) as the number of mammal remains increased, suggesting the inhabitants of Takarkori gradually focused more on hunting/livestock. The authors also found the proportion of tilapia specifically decreased more significantly over time, which may have been because catfish have accessory breathing organs allowing them to breathe air and survive in shallow, high-temperature waters—further evidence that this now-desert environment became less favorable to fish as the aridity increased.
The authors add: "This study reveals the ancient hydrographic network of the Sahara and its interconnection with the Nile, providing crucial information on the dramatic climate changes that led to the formation of the largest hot desert in the world. Takarkori rock shelter has once again proved to be a real treasure for African archaeology and beyond: a fundamental place to reconstruct the complex dynamics between ancient human groups and their environment in a changing climate.
More information: Van Neer W, Alhaique F, Wouters W, Dierickx K, Gala M, Goffette Q, et al. (2020) Aquatic fauna from the Takarkori rock shelter reveals the Holocene central Saharan climate and palaeohydrography. PLoS ONE 15(2): e0228588. doi.org/10.1371/journal.pone.0228588
A group of Russian and German palaeontologists have described a previously unknown genus and species of prehistoric salamanders. The new amphibian is named Egoria malashichevi -- in honor of Yegor Malashichev a talented scientist and associate professor of the Department of Vertebrate Zoology at St Petersburg University, who passed away at the end of 2018. Credit: Pavel Skutschas
A group of Russian and German palaeontologists have described a previously unknown genus and species of prehistoric salamanders. The new amphibian is named Egoria malashichevi—in honor of Yegor Malashichev a talented scientist and associate professor of the Department of Vertebrate Zoology at St Petersburg University, who passed away at the end of 2018.
The palaeontologists found the remains of the ancient amphibian at the Berezovsky quarry, a fossil locality in the Krasnoyarsk Krai near the town of Sharypovo. Fossils of ancient fish, various reptiles, mammals, herbivorous and predatory dinosaurs have been previously found there. The research materials were collected on field expeditions in the mid-2010s. In these expeditions the scientists from St Petersburg University worked alongside experts from the University of Bonn (Germany), the Tomsk State University, the Zoological Institute of the Russian Academy of Sciences, and the Sharypovo Museum of Local History and Nature.
Four vertebrate fossils enabled the scientists to declare the finding of a new genus and species. These were: three trunk vertebrae and the atlas—the first and, in the case of the salamander, the only cervical vertebra. Since the atlas is a highly specialised vertebra, providing for attachment and rotation movements of the skull, it has a rather complex structure, the scientists explain. It is therefore most suitable for describing a new species as it provides much information for analysis. The amphibian proved to have belonged to the geologically oldest stem salamanders.
It was not the first time that remains of ancient salamanders had been found at the Berezovsky quarry. One of them—a basal stem salamander Urupia monstrosa, named after the nearby Uryup River—was about 50-60 centimetres long. Another one—Kiyatriton krasnolutskii—was named after a local historian Sergei Krasnolutskii, the discoverer of the fossil locality Berezovsky quarry. By contrast, this one was quite small in size (about 10-15 centimetres) and looked more like modern Hynobiidae. The newly discovered salamander, judging by the size of the vertebrae, was of medium length (about 20 centimetres).
A group of Russian and German palaeontologists have described a previously unknown genus and species of prehistoric salamanders. The new amphibian is named Egoria malashichevi -- in honor of Yegor Malashichev a talented scientist and associate professor of the Department of Vertebrate Zoology at St Petersburg University, who passed away at the end of 2018. Credit: Vadim Glinskiy
"Salamanders first appear in the fossil records in the Middle Jurassic, including representatives of both the present-day salamander families and the most primitive ones," said Pavel Skutschas, associate professor of St Petersburg University, doctor of biology, expert in Mesozoic vertebrates. "When they had just appeared, salamanders made efforts to occupy different ecological niches. Thus, the stem salamanders filled the niche of large water bodies; while those close to the present-day salamanders found their niche in small water bodies. As for the newly discovered salamander, it occupied a middle position, although morphologically, it is closer to the primitive."
The scientists not only described the external characteristics of the specimens, but were able to look inside the fossils. In this they were assisted by the experts from the "Centre of X-ray diffraction studies' at the Research Park of St Petersburg University, where the specimens were scanned on up-to-date microtomography scanners. Based on the obtained data, the palaeontologists created 3-D reconstructions of the vertebrae and described their internal structure. As expected, it proved to be very similar to that of the large stem salamanders.
A group of Russian and German palaeontologists have described a previously unknown genus and species of prehistoric salamanders. The new amphibian is named Egoria malashichevi -- in honor of Yegor Malashichev a talented scientist and associate professor of the Department of Vertebrate Zoology at St Petersburg University, who passed away at the end of 2018. Credit: Pavel Skutschas
The ancient amphibian received the name Egoria malashichevi—in honour of Yegor Malashichev, associate professor of the Department of Vertebrate Zoology at St Petersburg University, who, among other things, studied the morphology of caudate amphibians. "Yegor Malashichev was a wonderful person and a very talented scientist. He supported aspiring palaeontologists and did everything to help them to stay in scientific research," remarked Pavel Skutschas. Additionally, Malashichev studied the phenomenon of lateralisation (body asymmetries associated with the functioning of the nervous system), as well as other asymmetries in motor performance and visual perception. Yegor Malashichev's professional career was almost exclusively connected with St Petersburg University. In 1996, he graduated from the Faculty of Biology and Soil Science. In 2000, he began to teach there, and in 2003, he defended his dissertation and was awarded a Ph.D. in biology. Sadly, in late 2018, he passed away unexpectedly.
The next step for the palaeontologists is to compare the bones of the 'Berezovsky' salamanders with the fossils from Great Britain: the 'Kirtlington' salamanders which were found at the Kirtlington quarry in Oxfordshire. The Siberian and British faunas of the mid-Jurassic time were very similar. Besides, the palaeontologists are aware of similar amphibians that lived in the territory of present-day England. "They may be representatives of the same genera. However, to ascertain this, a detailed comparison of the palaeontological collections is required. In the coming spring, our colleagues from England will come to St Petersburg to study our research materials. We may discover that Urupia and Egoria used to have a very wide habitat, extending across Europe and Asia," said Pavel Skutschas.
