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)
Thursday, January 02, 2020
The World's Oldest 'Fossil Forest' Was Just Discovered in New York State
The oldest forest in the world was just discovered in upstate New York, just west of the Hudson River and a bit south of Albany.
Discovered in a limestone quarry, all that remains of the 386-million-year-old forest are some fossilized root networks in a Cairo, N.Y. limestone quarry. Long ago, the giant trees of the ancient forest likely covered a region stretching into Pennsylvania and beyond, the researchers wrote. And they're about 2 to 3 million years older than the previous record-holder for the most ancient forest, discovered 25 miles (40 kilometers) west in Gilboa, New York.
"It is surprising to see plants which were previously thought to have had mutually exclusive habitat preferences growing together," said Chris Berry, a researcher at Cardiff University in Wales and co-author of a study on the ancient forest published Dec. 19 in the journal Current Biology, in a statement.
When the forest existed, this part of the Hudson Valley was a river delta, which is why fish fossils were found in the same quarry.
None of the trees in the old woods reproduced using multicellular seeds, the researchers wrote, and instead produced offspring using single-cell spores. There were three types of tree in the ancient forest: cladoxylopsids, which were like primitive ferns without the flat green leaves (these were also widespread at the Gilboa site); archaeopteris, which in some respects resembled modern conifers but had flat, green leaves; and a single example of a third, unidentified type of tree.
This forest, the researchers wrote, reveals a key milestone in Earth's climate history. As plants developed thick, long-lived, carbon-rich wooden roots, they pulled carbon dioxide out of the atmosphere, fundamentally changing the global composition of the planet's air. Plants themselves became significant carbon sinks.
Eventually, this forest was wiped out, likely by a flood, the researchers surmised.
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Demon with Forked Tongue Found on Clay Tablet in Library of Assyrian Exorcists
The drawing was overlooked for decades on the tablet from the library of a family of exorcists who lived in the Assyrian city of Assur. The depiction is shown here in red.
An ancient drawing of a demon blamed for epileptic seizures has been discovered on a 2,700-year-old Assyrian clay tablet.
University of Copenhagen Assyriologist Troels Pank Arbøll was examining a tablet of ancient writing at the Vorderasiatisches Museum in Berlin when he noticed the drawing of the demon — portrayed with horns, a tail and a snake-like forked tongue.
The tablet came from the library of a family of exorcists who lived in about 650 B.C. in the city of Assur, now in northern Iraq, Arbøll said. But it's likely it was copied from a much older text.
The tablet is written in cuneiform — a very early system of letters formed by pressing a triangular stylus into softened clay.
The inscription describes cures for convulsions, twitches and other involuntary muscle movements — an affliction called "Bennu" by the Assyrians and now interpreted as symptoms of epilepsy.
Ancient Assyrians, however, thought Bennu was caused by demonic possession.
The 2,700-year-old drawing of the demon thought by the Assyrians to cause the convulsive seizures of Bennu, or epilepsy, was spotted on an ancient clay tablet. (Image credit: Troels Pank Arbøll)
"I was the first one to notice the drawing, despite the text having been known to researchers for decades," Arbøll told Live Science in an email, "so it is not easily seen today unless one knows it is there due to the damage on the manuscript."
In new research published last month in Le Journal des Médecines Cunéiformes, Arbøll describes the demon as having "curvy horns, a serpent's tongue and possibly a reptile-like eye. … The creature has a long tail placed alongside the left leg…."
I have a new article out on a newly discovered drawing of a Neo-Assyrian demon connected to psychological and neurological disorders, which may be the earliest illustration of epilepsy in a demonic form (see drawing)! Available for free via following link https://t.co/Wo2P6MUoMp pic.twitter.com/lAVNZX7bAmNovember 8, 2019
Epilepsy demon
Arbøll determined the outlines of the damaged drawing over the months that followed his discovery; the text, he suggests, shows the demon that causes Bennu on behalf of the Mesopotamian moon god Sîn.
The ancient Assyrians believed epilepsy was related to madness, and that both were caused by the moon god, he said. This ancient idea is reflected in an English word for madness — lunacy — which implies a connection with the moon, called "luna" in Latin.
Drawings on cuneiform tablets are rare, and portraits of demons are even rarer: "This specific drawing is a depiction of the actual demon, instead of other comparable drawings, which generally depict a figurine made during a ritual to remove the illness," Arbøll said.
The Assyrians did not distinguish between magic and medicine, and magical remedies like rituals and incarnations were used alongside remedies that would be seen as medical today, like ingested potions, external ointments and bandages.
"Doctors" of the time would have treated Bennu-epilepsy by placing a leather amulet around the infected person's neck, heating various ingredients on hot coals and directing the resulting smoke toward the patient, Arbøll said. "Less often, we find mixtures to be ingested or salves applied to the patient."
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There's a Giant Mystery Hiding Inside Every Atom in the Universe
No one really knows what happens inside an atom. But two competing groups of scientists think they've figured it out. And both are racing to prove that their own vision is correct.
Here's what we know for sure: Electrons whiz around "orbitals" in an atom's outer shell. Then there's a whole lot of empty space. And then, right in the center of that space, there's a tiny nucleus — a dense knot of protons and neutrons that give the atom most of its mass. Those protons and neutrons cluster together, bound by what's called the strong force. And the numbers of those protons and neutrons determine whether the atom is iron or oxygen or xenon, and whether it's radioactive or stable.
Still, no one knows how those protons and neutrons (together known as nucleons) behave inside an atom. Outside an atom, protons and neutrons have definite sizes and shapes. Each of them is made up of three smaller particles called quarks, and the interactions between those quarks are so intense that no external force should be able to deform them, not even the powerful forces between particles in a nucleus. But for decades, researchers have known that the theory is in some way wrong. Experiments have shown that, inside a nucleus, protons and neutrons appear much larger than they should be. Physicists have developed two competing theories that try to explain that weird mismatch, and the proponents of each are quite certain the other is incorrect. Both camps agree, however, that whatever the correct answer is, it must come from a field beyond their own.
Since at least the 1940s, physicists have known that nucleons move in tight little orbitals within the nucleus, Gerald Miller, a nuclear physicist at the University of Washington, told Live Science. The nucleons, confined in their movements, have very little energy. They don't bounce around much, restrained by the strong force.
In 1983, physicists at the European Organization for Nuclear Research (CERN) noticed something strange: Beams of electrons bounced off iron in a way that was very different from how they bounced off free protons, Miller said. That was unexpected; if the protons inside hydrogen were the same size as the protons inside iron, the electrons should have bounced off in much the same way
At first, researchers didn't know what they were looking at.
But over time, scientists came to believe it was a size issue. For some reason, protons and neutrons inside heavy nuclei act as if they are much larger than when they are outside the nuclei. Researchers call this phenomenon the EMC effect, after the European Muon Collaboration — the group that accidentally discovered it. It violates existing theories of nuclear physics.
Or Hen, a nuclear physicist at MIT, has an idea that could potentially explain what's going on.
While quarks, the subatomic particles that make up nucleons, strongly interact within a given proton or neutron, quarks in different protons and neutrons can't interact much with each other, he said. The strong force inside a nucleon is so strong it eclipses the strong force holding nucleons to other nucleons.
"Imagine sitting in your room talking to two of your friends with the windows closed," Hen said.eutron to nearby nucleons that are "outside" the window. Even if a little snuck through the closed window, Hen said, it would barely affect you.
And as long as nucleons stay in their orbitals, that's the case. However, he said, recent experiments have shown that at any given time, about 20% of the nucleons in a nucleus are in fact outside their orbitals. Instead, they're paired off with other nucleons, interacting in "short range correlations." Under those circumstances, the interactions between the nucleons are much higher-energy than usual, he said. That's because the quarks poke through the walls of their individual nucleons and start to directly interact, and those quark-quark interactions are much more powerful than nucleon-nucleon interactions.
These interactions break down the walls separating quarks inside individual protons or neutrons, Hen said. The quarks making up one proton and the quarks making up another proton start to occupy the same space. This causes the protons (or neutrons, as the case may be) to stretch and blur, Hen said. They grow a lot, albeit for very short periods of time. That skews the average size of the entire cohort in the nucleus — producing the EMC effect.
Most physicists now accept this interpretation of the EMC effect, Hen said. And Miller, who worked with Hen on some of the key research, agreed.
But not everyone thinks Hen's group has the problem worked out. Ian Cloët, a nuclear physicist at Argonne National Laboratory in Illinois, said he thinks Hen's work draws conclusions that the data doesn't fully support.
"I think the EMC effect is still unresolved," Cloët told Live Science. That's because the basic model of nuclear physics already accounts for a lot of the short-range pairing Hen describes. Yet, "if you use that model to try and look at the EMC effect, you will not describe the EMC effect. There is no successful explanation of the EMC effect using that framework. So in my opinion, there's still a mystery."
Hen and his collaborators are doing experimental work that is "valiant" and "very good science," he said. But it doesn't fully resolve the problem of the atomic nucleus.
"What is clear is that the traditional model of nuclear physics … cannot explain this EMC effect," he said. "We now think that the explanation must be coming from QCD itself."
QCD stands for quantum chromodynamics — the system of rules that govern the behavior of quarks. Shifting from nuclear physics to QCD is a bit like looking at the same picture twice: once on a first-generation flip phone — that's nuclear physics — and then again on a high-resolution TV — that's quantum chromodynamics. The high-res TV offers a lot more detail, but it's a lot more complicated to build.
The problem is that the complete QCD equations describing all the quarks in a nucleus are too difficult to solve, Cloët and Hen both said. Modern supercomputers are about 100 years away from being fast enough for the task, Cloët estimated. And even if supercomputers were fast enough today, the equations haven't advanced to the point where you could plug them into a computer, he said.
Still, he said, it's possible to work with QCD to answer some questions. And right now, he said, those answers offer a different explanation for the EMC effect: Nuclear Mean-Field Theory.
He disagrees that 20% of nucleons in a nucleus are bound up in short-range correlations. The experiments just don't prove that, he said. And there are theoretical problems with the idea.
That suggests we need a different model, he said.
"The picture that I have is, we know that inside a nucleus are these very strong nuclear forces," Cloët said. These are "a bit like electromagnetic fields, except they're strong force fields."
The fields operate at such tiny distances that they're of negligible magnitude outside the nucleus, but they're powerful inside of it.
In Cloët's model, these force fields, which he calls "mean fields" (for the combined strength they carry) actually deform the internal structure of protons, neutrons and pions (a type of strong force-carrying particle).
"Just like if you take an atom and you put it inside a strong magnetic field, you will change the internal structure of that atom," Cloët said.
In other words, mean-field theorists think the sealed-up room Hen described has holes in its walls, and wind is blowing through to knock the quarks around, stretching them out.
Cloët acknowledged that it's possible short-range correlations likely explain some portion of the EMC effect, and Hen said mean fields likely do play a role as well.
"The question is, which dominates," Cloët said.
Miller, who has also worked extensively with Cloët, said that the mean field has the advantage of being more well-grounded in theory. But Cloët hasn't yet done all the necessary calculations, he said.
And right now the weight of experimental evidence suggests that Hen has the better of the argument.
Hen and Cloët both said the results of experiments in the next few years could resolve the question. Hen cited an experiment underway at Jefferson National Accelerator Facility in Virginia that will move nucleons closer together, bit by bit, and allow researchers to watch them change. Cloët said he wants to see a "polarized EMC experiment" that would break up the effect based on the spin (a quantum trait) of the protons involved. It might reveal unseen details of the effect that could aid calculations, he said.
All three researchers emphasized that the debate is friendly.
"It's great, because it means we're still making progress," Miller said. "Eventually, something's going to be in the textbook and the ball game is over. ... The fact that there's two competing ideas means that it's exciting and vibrant. And now finally we have the experimental tools to resolve these issues."
CHEMISTRY
Want to Crack Open a Safe? Try Nitroglycerine January 1856
January 2, 2020
Credit: Scientific American
“Today the safe-breaker no longer requires those beautifully fashioned, delicate yet powerful tools which were formerly both the admiration and the despair of the safe manufacturer. For the introduction of nitroglycerine, ‘soup’ in technical parlance, has not only obviated onerous labor, but has again enabled the safe-cracking industry to gain a step on the safe-making one. The modern ‘yeggman,’ however, is often an inartistic, untidy workman, for it frequently happens that when the door suddenly parts company with the safe it takes the front of the building with it. The bombardment of the surrounding territory with portions of the Farmers’ National Bank seldom fails to rouse from slumber even the soundly-sleeping tillers of the soil.”
—Scientific American, January 1856
Australia’s Angry Summer: This Is What Climate Change Looks Like
The catastrophic fires raging across the southern half of the continent are largely the result of rising temperatures
Summer in Australia use to be something we yearned for: long, lazy days spent by the beach or pool, backyard barbecues, and games of cricket with family and friends. But recent summers have become a time of fear: Schools and workplaces are closed because of catastrophic fire danger, while we shelter in air-conditioned spaces to avoid dangerous heat waves and hazardous levels of smoke in the air. Campgrounds have been closed for the summer, and entire towns have been urged to evacuate ahead of “Code Red” fire weather. Welcome to our new climate.
Of course, unusually hot summers have happened in the past; so have bad bushfire seasons. But the link between the current extremes and anthropogenic climate change is scientifically undisputable.
The fires raging across the southern half of the Australian continent this year have so far burned through more than 5 million hectares. To put that in context, the catastrophic 2018 fire season in California saw nearly 740,000 hectares burned. The Australian fire season began this year in late August (before the end of our winter). Fires have so far claimed nine lives, including two firefighters, and destroyed around 1,000 homes. It is too early to tell what the toll on our wildlife has been, but early estimates suggest that around 500 million animals have died so far, including 30 percent of the koala population in their main habitat. And this is all before we have even reached January and February, when the fire season typically peaks in Australia.
Australia is the most fire prone of all of Earth’s continents. But what has made its latest fire season so extreme? Wildfires need four ingredients: available fuel, dryness of that fuel, weather conditions that aid the rapid spread of fire and an ignition. Climate change is making Australian wildfires larger and more frequent because of its effects on dryness and fire weather.
Australia’s climate has warmed by more than one degree Celsius over the past century, and this change has caused an increase in the frequency and intensity of heat waves. I am 42, and I have lived through only six years with average temperatures below the 1961–1990 climatological average. My children have experienced none, and in all likelihood, they never will.
One of the factors driving this long-term loss of winter rainfall is the positive trend in the Southern Annular Mode (SAM). This change is causing the westerly winds that circle the Southern Ocean to shift southward toward Antarctica, causing rain-bearing winter cold fronts to pass south of the Australian continent. The role of anthropogenic climate change in driving this trend in the SAM is also clear in the science.
Climate variability acts on top of these long-term trends that are pushing the Australian climate toward a more fire-prone state. And that variability is an important part of the story of why the 2019–2020 summer has been so extreme.
Southeastern Australia has been in drought since 2017. Rainfall here is normally highly variable from year to year, but there have now been three winters in a row where the winter rains failed. This is a situation that has never been seen before in the historical record of Australia’s rainfall, even during infamous decade-long droughts such as the Millennium Drought. The severity of the current drought has caused large swathes of vegetation to die. It has even dried out wet rain forests, allowing fierce fires to take hold in places that would not normally burn
The current summer has presented the perfect storm for wildfire. Long-term climate warming, combined with years of drought, colliding with a set of climate patterns that deliver severe fire weather.
In the tropical Indian Ocean, one of the most severe positive Indian Ocean Dipole (IOD) events on record played out this year. The unusually cold sea-surface temperatures in the eastern Indian Ocean cut off one of Australia’s critical moisture sources, adding to the ongoing drought in southern parts of the country. Australia’s worst fire seasons typically follow positive IOD events, much more so than the influence of El Niño events in the Pacific. Again, climate change is part of the story, because anthropogenic warming is causing positive IOD events to become stronger and more frequent.
At the same time, this year, a rare sudden stratospheric warming event developed over the Antarctic in late winter. Weakening of the polar vortex over Antarctica in spring increases the forest fire danger index across eastern Australia. This is because a northward shift in the Southern Hemisphere westerlies (i.e., a negative SAM) at this time of year causes very hot and dry westerly winds to be drawn across the continent.
The angry summer playing out in Australia right now was predictable. The scientific evidence is well known for how anthropogenic greenhouse gas emissions are causing long-term climate change and altering climate variability in ways that increase our fire risk. The role of climate change in the unprecedented fires gripping Australia is also well understood by our emergency services. Sadly, though, this summer has occurred against a backdrop in which the Australian government has argued, on the world stage, to scale back our greenhouse-gas-emissions-reduction targets. Our leaders are literally fiddling while the country burns.
In many parts of Australia, there will be no traditional fireworks shows to welcome in the new year. The risk is simply too great, and celebration is not warranted while our communities continue to be under threat from this angry summer.
The views expressed are those of the author(s) and are not necessarily those of Scientific American.
Nerilie Abram is an investigator at the ARC Center of Excellence for Climate Extremes and an associate professor at the Research School of Earth Sciences at the Australian National University.
Capturing CO2 from trucks and reducing their emissions by 90%
ECOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE
IMAGE: RESEARCHERS AT EPFL HAVE PATENTED A NEW CONCEPT THAT COULD CUT TRUCKS' CO2 EMISSIONS BY ALMOST 90%. IT INVOLVES CAPTURING CO2 WITHIN THE EXHAUST SYSTEM, CONVERTING IT INTO A LIQUID... view more
CREDIT: EPFL / FRANÇOIS MARÉCHAL
In Europe, transport is responsible for nearly 30% of the total CO2 emissions, of which 72% comes from road transportation*. While the use of electric vehicles for personal transportation could help lower that number, reducing emissions from commercial transport - such as trucks or buses - is a much greater challenge.
Researchers at EPFL have now come up with a novel solution: capturing CO2 directly in the trucks' exhaust system and liquefying it in a box on the vehicle's roof. The liquid CO2 is then delivered to a service station, where it is turned into conventional fuel using renewable energy. The project is being coordinated by the Industrial Process and Energy Systems Engineering group, led by François Maréchal, at EPFL's School of Engineering. The patented concept is the subject of a paper published in Frontiers in Energy Research.
A complex process onboard the vehicle
Scientists propose to combine several technologies developed at EPFL to capture CO2 and convert it from a gas to a liquid in a process that recovers most of energy available onboard, such as heat from the engine. In their study, the scientists used the example of a delivery truck.
First, the vehicle's flue gases in the exhaust pipe are cooled down and the water is separated from the gases. CO2 is isolated from the other gases (nitrogen and oxygen) with a temperature swing adsorption system, using metal-organic frameworks (MOFs) adsorbent, which are specially designed to absorb CO2. Those materials are being developed by the Energypolis team at EPFL Valais Wallis, led by Wendy Queen. Once the material is saturated with CO2, it is heated so that pure CO2 can be extracted from it. High speed turbocompressors developed by Jürg Schiffmann's laboratory at EPFL's Neuchâtel campus use heat from the vehicle's engine to compress the extracted CO2 and turn it into a liquid. That liquid is stored in a tank and can then be converted back into conventional fuel at the service stations using renewable electricity. "The truck simply deposits the liquid when filling up with fuel," says Maréchal.
The whole process takes place within a capsule measuring 2 m x 0.9 m x 1.2 m, placed above the driver's cabin. "The weight of the capsule and the tank is only 7% of the vehicle's payload," adds Maréchal. "The process itself uses little energy, because all of its stages have been optimized."
The researchers' calculations show that a truck using 1 kg of conventional fuel could produce 3kg of liquid CO2, and that the conversion does not involve any energy penalty.
Only 10% of the CO2 emissions cannot be recycled, and the researchers propose to offset that using biomass.
The system could theoretically work with all trucks, buses and even boats, and with any type of fuel. The advantage of this system is that, unlike electric or hydrogen-based ones, it can be retrofitted to existing trucks in order to neutralize their impact in terms of carbon emissions.
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Source: Shivom Sharma and François Maréchal, Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption, Frontiers in Energy Research
The growing Tibetan Plateau shaped the modern biodiversity
Holding particular biological resources, the Tibetan Plateau is a unique geologic-geographic-biotic interactively unite and hence plays an important role in the global biodiversity domain. The Tibetan Plateau has undergone vigorous environmental changes since the Cenozoic, and played roles as switching from "a paradise of tropical animals and plants" to "the cradle of Ice Age mammalian fauna". Recent significant paleontological discoveries have refined a big picture of the evolutionary history of biodiversity on that plateau against the backdrop of major environmental changes, and paved the way for the assessment of its far-reaching impact upon the biota around the plateau and even in more remote regions. Based on the newly reported fossils from the Tibetan Plateau which include diverse animals and plants, this paper presented general viewpoints of the biodiversity history on the Tibetan Plateau and its influence in a global scale.
This paper defined the Tibetan Plateau as an evolutionary junction of the history of modern biodiversity, whose performance can be categorized in the following three patterns: (1) Local origination of endemism; (2) Local origination and "Out of Tibet"; (3) Intercontinental dispersal via Tibet.
The first pattern is exemplified by the snow carps (schizothoracine fishes), the major component of the freshwater fish fauna on the plateau, whose temporal distribution pattern of the fossil schizothoracines approximately mirrors the spatial distribution pattern of their living counterparts. Through ascent with modification, their history reflects the biological responses to the stepwise uplift of the Tibetan Plateau.
The second pattern is represented by the dispersal history of some mammals since the Pliocene and some plants. The ancestors of some Ice Age mammals, e.g., the wholly rhino, Arctic fox, and argali sheep first originated and evolved in the uplifted and frozen Tibet during the Pliocene, and then migrated toward the Arctic regions or even the North American continent at beginning of the Ice Age; the ancestor of pantherines (big cats) first rose in Tibetan Plateau during the Pliocene, followed by the disperse of its descendants to other parts of Asia, Africa, North and South America to play as top predators of the local ecosystems. The early members of some plants, e.g., Elaeagnaceae appeared in Tibet during the Late Eocene and then dispersed and widely distributed to other regions.
The last pattern is typified by the history of the tree of heaven (Ailanthus) and climbing perch. Ailanthus originated in the Indian subcontinent, then colonized into Tibet after the Indian-Asian plate collision, and dispersed from the Tibetan Plateau to East Asia, Europe and even North America. The climbing perches among freshwater fishes probably rose in Southeast Asia during the Middle Eocene, dispersed to Tibet and then migrated into Africa via the docked India. These cases highlight the role of Tibet, which was involved in the continental collision, in the intercontinental biotic interchanges. The three evolutionary patterns above reflect both the history of biodiversity on the plateau as well as the biological and environmental effects of tectonic uplift.
Since the initiation of the Second Tibetan Plateau Scientific Expedition in 2017, this review is the first comprehensive conclusions on the relationship between the uplift of the Tibetan Plateau and the evolution of biota based on latest numerous fossil records. It provides important scientific evidence for the influence of the uplift of the Tibetan Plateau on the environment and biota.
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This paper is entitled "Tibetan Plateau: An evolutionary junction for the history of modern biodiversity", with coauthors Tao Deng and Feixiang Wu from Institute of Vertebrate Paleontology and Paleoanthropology, Zhekun Zhou and Tao Su from Xishuangbanna Tropical Botanical Garden, CAS. It is published in special issue "Cenozoic mammals and plants from Tibetan Plateau and their biogeographical significance" in Science China: Earth Science.
This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB26000000, XDA20070203, XDA20070301), the Second Comprehensive Scientific Expedition on the Tibetan Plateau (Grant No. QZK0705, 2019), the National Natural Science Foundation of China (Grant Nos. 41430102, 41872006), the Frontier Science Key Research Project (Grant No. QYZDY-SSW-DQC022), the International Partnership Program (Grant No. GJHZ1885), and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2017103).
See the article: Deng T, Wu F, Su T, Zhou Z. 2019. Tibetan Plateau: An evolutionary junction for the history of modern biodiversity. Science China Earth Sciences, https://doi.org/10.1007/s11430-019-9507-5
Learning from the bears
MAX DELBRÜCK CENTER FOR MOLECULAR MEDICINE IN THE HELMHOLTZ ASSOCIATION
IMAGE: GRIZZLY BEARS' MUSCLES MANAGE TO SURVIVE HIBERNATION VIRTUALLY UNHARMED. RESEARCHERS ARE TRYING TO UNDERSTAND THE MECHANISMS BEHIND THIS ABILITY IN ORDER TO HELP BEDRIDDEN PATIENTS. view more
CREDIT: GOTTHARDT LAB, MDC
Grizzly bears spend many months in hibernation, but their muscles do not suffer from the lack of movement. In the journal "Scientific Reports", a team led by Michael Gotthardt reports on how they manage to do this. The grizzly bears' strategy could help prevent muscle atrophy in humans as well.
A grizzly bear only knows three seasons during the year. Its time of activity starts between March and May. Around September the bear begins to eat large quantities of food. And sometime between November and January, it falls into hibernation. From a physiological point of view, this is the strangest time of all. The bear's metabolism and heart rate drop rapidly. It excretes neither urine nor feces. The amount of nitrogen in the blood increases drastically and the bear becomes resistant to the hormone insulin.
A person could hardly survive this four-month phase in a healthy state. Afterwards, he or she would most likely have to cope with thromboses or psychological changes. Above all, the muscles would suffer from this prolonged period of disuse. Anyone who has ever had an arm or leg in a cast for a few weeks or has had to lie in bed for a long time due to an illness has probably experienced this.
A little sluggish, but otherwise fine
Not so the grizzly bear. In the spring, the bear wakes up from hibernation, perhaps still a bit sluggish at first, but otherwise well. Many scientists have long been interested in the bear's strategies for adapting to its three seasons.
A team led by Professor Michael Gotthardt, head of the Neuromuscular and Cardiovascular Cell Biology group at the Max Delbrueck Center for Molecular Medicine (MDC) in Berlin, has now investigated how the bear's muscles manage to survive hibernation virtually unharmed. The scientists from Berlin, Greifswald and the United States were particularly interested in the question of which genes in the bear's muscle cells are transcribed and converted into proteins, and what effect this has on the cells.
Understanding and copying the tricks of nature
"Muscle atrophy is a real human problem that occurs in many circumstances. We are still not very good at preventing it," says the lead author of the study, Dr. Douaa Mugahid, once a member of Gotthardt's research group and now a postdoctoral researcher in the laboratory of Professor Marc Kirschner of the Department of Systems Biology at Harvard Medical School in Boston.
"For me, the beauty of our work was to learn how nature has perfected a way to maintain muscle functions under the difficult conditions of hibernation," says Mugahid. "If we can better understand these strategies, we will be able to develop novel and non-intuitive methods to better prevent and treat muscle atrophy in patients."
Gene sequencing and mass spectrometry
To understand the bears' tricks, the team led by Mugahid and Gotthardt examined muscle samples from grizzly bears both during and between the times of hibernation, which they had received from Washington State University. "By combining cutting-edge sequencing techniques with mass spectrometry, we wanted to determine which genes and proteins are upregulated or shut down both during and between the times of hibernation," explains Gotthardt.
"This task proved to be tricky - because neither the full genome nor the proteome, i.e., the totality of all proteins of the grizzly bear, were known," says the MDC scientist. In a further step, he and his team compared the findings with observations of humans, mice and nematode worms.
Non-essential amino acids allowed muscle cells to grow
As the researchers reported in the journal "Scientific Reports", they found proteins in their experiments that strongly influence a bear's amino acid metabolism during hibernation. As a result, its muscle cells contain higher amounts of certain non-essential amino acids (NEAAs).
"In experiments with isolated muscle cells of humans and mice that exhibit muscle atrophy, cell growth could also be stimulated by NEAAs," says Gotthardt, adding that "it is known, however, from earlier clinical studies that the administration of amino acids in the form of pills or powders is not enough to prevent muscle atrophy in elderly or bedridden people."
"Obviously, it is important for the muscle to produce these amino acids itself - otherwise the amino acids might not reach the places where they are needed," speculates the MDC scientist. A therapeutic starting point, he says, could be the attempt to induce the human muscle to produce NEAAs itself by activating corresponding metabolic pathways with suitable agents during longer rest periods.
Tissue samples from bedridden patients
In order to find out which signaling pathways need to be activated in the muscle, Gotthardt and his team compared the activity of genes in grizzly bears, humans and mice. The required data came from elderly or bedridden patients and from mice suffering from muscle atrophy - for example, as a result of reduced movement after the application of a plaster cast. "We wanted to find out which genes are regulated differently between animals that hibernate and those that do not," explains Gotthardt.
However, the scientists came across a whole series of such genes. To narrow down the possible candidates that could prove to be a starting point for muscle atrophy therapy, the team subsequently carried out experiments with nematode worms. "In worms, individual genes can be deactivated relatively easily and one can quickly see what effects this has on muscle growth," explains Gotthardt.
A gene for circadian rhythms
With the help of these experiments, his team has now found a handful of genes whose influence they hope to further investigate in future experiments with mice. These include the genes Pdk4 and Serpinf1, which are involved in glucose and amino acid metabolism, and the gene Rora, which contributes to the development of circadian rhythms. "We will now examine the effects of deactivating these genes," says Gotthardt. "After all, they are only suitable as therapeutic targets if there are either limited side effects or none at all."
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Literature
Douaa Mugahid et al. (2019): "Proteomic and Transcriptomic Changes in Hibernating Grizzly Bears Reveal Metabolic and Signaling Pathways that Protect against Muscle Atrophy," Scientific Reports, DOI: 10.1038/s41598-019-56007-8
Max Delbrueck Center for Molecular Medicine (MDC)
The Max Delbrueck Center for Molecular Medicine in the Helmholtz Association (MDC) was founded in Berlin in 1992. It is named for the German-American physicist Max Delbrueck, who was awarded the 1969 Nobel Prize in Physiology and Medicine. The MDC's mission is to study molecular mechanisms in order to understand the origins of disease and thus be able to diagnose, prevent, and fight it better and more effectively. In these efforts the MDC cooperates with Charite - Universitätsmedizin Berlin and the Berlin Institute of Health (BIH) as well as with national partners such as the German Center for Cardiovascular Research (DZHK) and numerous international research institutions. More than 1,600 staff and guests from nearly 60 countries work at the MDC, just under 1,300 of them in scientific research. The MDC is funded by the German Federal Ministry of Education and Research (90 percent) and the State of Berlin (10 percent), and is a member of the Helmholtz Association of German Research Centers. http://www.mdc-berlin.de
CLIMATE AND HEALTH Scientists link La Niña climate cycle to increased diarrhea
COLUMBIA UNIVERSITY'S MAILMAN SCHOOL OF PUBLIC HEALTH
A study in Botswana by Columbia University Mailman School of Public Health scientists finds that spikes in cases of life-threatening diarrhea in young children are associated with La Niña climate conditions. The findings published in the journal Nature Communications could provide the basis for an early-warning system that would allow public health officials to prepare for periods of increased diarrhea cases as long as seven months ahead of time.
In low- and middle-income countries, diarrhea is the second leading cause of death in children younger than five years of age, with 72 percent of deaths occurring in the first two years of life. Rates of under-5 diarrhea in Africa are particularly high, with an estimated incidence of 3.3 episodes of diarrhea per child each year and one-quarter of all child deaths caused by diarrhea.
The El Niño-Southern Oscillation (ENSO) is a coupled ocean-atmosphere system spanning the equatorial Pacific Ocean that oscillates in a 3-to-7-year cycle between two extremes, El Niño (warmer ocean temperatures) and La Niña (cooler ocean temperatures). The ENSO cycle affects local weather patterns around the world, including temperatures, winds, and precipitation.
Researchers analyzed associations between ENSO and climate conditions and cases of under-5 diarrhea in the Chobe region in northeastern Botswana. They found that La Niña is associated with cooler temperatures, increased rainfall, and higher flooding during the rainy season. In turn, La Niña conditions lagged 0-7 months are associated with about a 30-percent increase in incidence of under-5 diarrhea in the early rainy season from December through February
"These findings demonstrate the potential use of the El Niño-Southern Oscillation as a long-lead prediction tool for childhood diarrhea in southern Africa," says first author Alexandra K. Heaney, a former doctoral student in environmental health sciences at Columbia Mailman and now a postdoc at University of California, Berkeley. "Advanced stockpiling of medical supplies, preparation of hospital beds, and organization of healthcare workers could dramatically improve the ability of health facilities to manage high diarrheal disease incidence."
Previously, El Niño events have been linked to diarrhea outbreaks in Peru, Bangladesh, China, and Japan, but until now studies of the effects of ENSO on diarrheal disease in Africa have been limited to cholera--a pathogen responsible for only a small fraction of diarrheal cases in Africa.
Infectious diarrhea is caused by many different pathogens (viruses, bacteria, and protozoa) and meteorological conditions can have a critical influence on pathogen exposures, in particular, those associated with waterborne transmission. For example, extreme rainfall events may contaminate drinking water by flushing diarrhea-causing pathogens from pastures and dwellings into drinking water supplies, and drought conditions can concentrate animal activity increasing the movement of diarrhea-causing pathogens into surface water resources.
Water Treatment Systems Appear To Be Strained
The researchers speculate that centralized water disinfection processes currently used in the Chobe region may be insufficient to deal with changes in water quality brought on by extremes of wet and dry weather, although they caution that further confirmatory studies are needed.
Earlier research by Columbia Mailman researchers in the Chobe region found that cases of diarrhea in young children spiked during extreme climate conditions, in both the wet and dry seasons. A second study reported on a method to forecast childhood diarrheal disease there. Because climate conditions vary from region to region, forecasts for infectious diseases must be region-specific. In other studies, the scientists have created forecasts for influenza, Ebola, and West Nile Virus. During the influenza season in the United States, they publish weekly regional forecasts with predictions on whether cases are expected to rise or fall and by how much.
Insights Into a Changing Climate in Southern Africa
Research into links between climate systems and infectious disease in Botswana also provides insights into long-term changes in weather patterns coming as a result of climate change.
"In Southern Africa, precipitation is projected to decrease," says Jeffrey Shaman, PhD, co-author and professor of environmental health sciences at the Columbia Mailman School. "This change, in a hydrologically dynamic region where both wildlife and humans exploit the same surface water resources, may amplify the public health threat of waterborne illness. For this reason, there is an urgent need to develop the water sector in ways that can withstand the extremes of climate change."
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Shaman is also director of the Columbia Mailman School's Climate and Health program and director of the Global Consortium on Climate and Health Education. Kathleen A. Alexander, Virginia Tech University, is a co-author. Funding was provided by an NIEHS T32 grant for Interdisciplinary Training in Climate and Health (ES023770) and the National Science Foundation Dynamics of Coupled Natural and Human Systems Award (#1518486).
How do conifers survive droughts? Study points to existing roots, not new growth
Scientists can't see underground, but computational models are providing a new way to investigate how root systems might be changing
UNIVERSITY AT BUFFALO
IMAGE: SCIENTISTS EMPLOYED COMPUTER MODELING TO STUDY HOW CONIFERS TAP INTO WATER SOURCES DURING DROUGHT. AS PART OF THE RESEARCH, THE TEAM COMPARED THE BEHAVIOR OF MODELED TREES TO THAT OF... view more
CREDIT: CHARLOTTE GROSSIORD
BUFFALO, N.Y. -- As the world warms, a new study is helping scientists understand how cone-bearing trees like pines and junipers may respond to drought.
The research addresses a classic question in the field: When conditions are dry for long periods of time, do trees survive by growing new roots to tap water sources, or by relying on established roots that already go deep?
The answer, at least for some cone-bearing trees, known as conifers, may be the latter, says Scott Mackay, PhD, professor of geography in the University at Buffalo College of Arts and Sciences. Mackay is an expert in ecohydrology and how trees take up water.
In the new study, he led a team that used computational modeling to investigate how pines and junipers access water sources during prolonged dry spells.
In simulations, trees of both species survived a five-year drought when they entered the dry period with deep roots already reaching into fractured bedrock, where water can be found. These modeled trees also used water in ways that matched well with observations of real trees that successfully weathered drought conditions at the Los Alamos Survival-Mortality (SUMO) experiment site in New Mexico.
"When the model was set up with roots in the groundwater, none of the trees died off," Mackay says. "When the model required the trees to grow the roots into the bedrock after simulations started, all the trees died off. Growing new roots, which itself requires water, took too long."
The study was a collaboration between scientists at UB, Duke University, the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Pacific Northwest National Laboratory, Oklahoma State University and the University of Utah.
The research, published online in New Phytologist in July 2019, appears in the journal's January 2020 issue, along with a more recent commentary on the paper's importance by Louis Santiago, PhD, a professor of botany and plant sciences at the University of California, Riverside.
"Mackay et al. (2020) were able to distinguish between two major hypotheses regarding the dynamics of root function during drought, and essentially establish theory, which can now be validated or refuted in other systems," Santiago writes in the commentary.
The study's results could help explain why some pines and junipers are able to survive droughts while other trees around them, including those of the same species, perish.
What's happening underground?
The inability to see underground -- to peer through soil and bedrock -- is a topic of frustration for scientists who research trees. Mackay's research addresses this conundrum, providing a new tool for deducing what might be happening down below.
"It's very difficult to see what's happening with a tree's roots. Digging these trees up is very difficult, and you would kill them in the process," Mackay says. "The model provides us with an additional lens of seeing below the surface. Below-ground is kind of a frontier, an area of research that's becoming more and more important."
The model his team employed in the study simulates the behavior of trees, including how they use water and carbon, both of which are needed to grow new tissue, including roots.
As Mackay explains, "Carbon is obtained through photosynthesis, and it has to be transported down from the canopy of the trees to grow roots. Water is needed as part of this transport process. So if the tree's roots are in dry soil and they can't obtain water, this can affect the tree's ability to move carbon around, which can in turn impair the growth of new roots. Our model captures this feedback."
By helping scientists understand the traits that set some pines and junipers up to survive droughts, the study could provide insights into how coniferous forests will respond to the pressures of climate change.
"Scientists are trying to forecast what's going to happen to the world's biomes under climate change, and models need to be physiologically realistic," Mackay says. "During past droughts, there's lots of evidence of what we might think of as hydrologic refugia -- pockets of woody species that have survived droughts by tapping into deeper water resources. Some models tend to overestimate tree mortality because they're not able to capture some of these refugia. If we can learn more about these refugia and how they're established, we can use that knowledge to create better models."
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The study was funded by the U.S. National Science Foundation, with additional support from Laboratory Directed Research & Development funding at Pacific Northwest National Laboratory, and the Swiss National Science Foundation.
