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A Sixth Sense? Magneto Receptive Humans???
#67
People can sense Earth’s magnetic field, brain waves suggest
A new study hints that humans have magnetoreception abilities, similar to some other animals
BY 
MARIA TEMMING 
1:05PM, MARCH 18, 2019

[Image: 031519_MT_magnetic-sense_feat.jpg][img=788x0]https://www.sciencenews.org/sites/default/files/2019/03/main/articles/031519_MT_magnetic-sense_feat.jpg[/img]
ANIMAL MAGNETISM  Like birds, bacteria and other creatures with an ability known as magnetoreception, humans can sense Earth’s magnetic field (illustrated), a new study suggests.

VCHAL/SHUTTERSTOCK

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A new analysis of people’s brain waves when surrounded by different magnetic fields suggests that people have a “sixth sense” for magnetism.
Birds, fish and some other creatures can sense Earth’s magnetic field and use it for navigation (SN: 6/14/14, p. 10). Scientists have long wondered whether humans, too, boast this kind of magnetoreception. Now, by exposing people to an Earth-strength magnetic field pointed in different directions in the lab, researchers from the United States and Japan have discovered distinct brain wave patterns that occur in response to rotating the field in a certain way.
These findings, reported in a study published online March 18 in eNeuro, offer evidence that people do subconsciously respond to Earth’s magnetic field — although it’s not yet clear exactly why or how our brains use this information.
“The first impression when I read the [study] was like, ‘Wow, I cannot believe it!’” says Can Xie, a biophysicist at Peking University in Beijing. Previous tests of human magnetoreception have yielded inconclusive results. This new evidence “is one step forward for the magnetoreception field and probably a big step for the human magnetic sense,” he says. “I do hope we can see replications and further investigations in the near future.”
During the experiment, 26 participants each sat with their eyes closed in a dark, quiet chamber lined with electrical coils. These coils manipulated the magnetic field inside the chamber such that it remained the same strength as Earth’s natural field but could be pointed in any direction. Participants wore an EEG cap that recorded the electrical activity of their brains while the surrounding magnetic field rotated in various directions.
This setup simulated the effect of someone turning in different directions in Earth’s natural, unchanging field without requiring a participant to actually move. (Complete stillness prevented motor-control thoughts from tainting brain waves due to the magnetic field.) The researchers compared these EEG readouts with those from control trials where the magnetic field inside the chamber didn’t move.
Joseph Kirschvink, a neurobiologist and geophysicist at Caltech, and colleagues studied alpha waves to determine whether the brain reacts to changes in magnetic field direction. Alpha waves generally dominate EEG readings while a person is sitting idle but fade when someone receives sensory input, like a sound or touch.
Sure enough, changes in the magnetic field triggered changes in people’s alpha waves. Specifically, when the magnetic field pointed toward the floor in front of a participant facing north — the direction that Earth’s magnetic field points in the Northern Hemisphere — swiveling the field counterclockwise from northeast to northwest triggered an average 25 percent dip in the amplitude of alpha waves. That change was about three times as strong as natural alpha wave fluctuations seen in control trials.

ROTATION REACTION When downward-pointing magnetic fields were rotated counterclockwise, from northeast to northwest, researchers saw a significant dip in participants’ alpha brain waves (left). Alpha waves are similarly dampened when someone receives sensory input like a sound or smell. This response was not seen when downward fields rotated clockwise (center) or were held steady (right).
Curiously, people’s brains showed no responses to a rotating magnetic field pointed toward the ceiling — the direction of Earth’s field in the Southern Hemisphere. Four participants were retested weeks or months later and showed the same responses.
“It’s kind of intriguing to think that we have a sense of which we’re not consciously aware,” says Peter Hore, a chemist at the University of Oxford who has studied birds’ internal compasses. But “extraordinary claims need extraordinary proof, and in this case, that includes being able to reproduce it in a different lab.”
Questions raised
If these findings are replicable, they pose several questions — such as why people seem to respond to downward- but not upward-pointing fields. Kirschvink and colleagues think they have an answer: “The brain is taking [magnetic] data, pulling it out and only using it if it makes sense,” Kirschvink says.
Participants in this study, who all hailed from the Northern Hemisphere, should perceive downward-pointing magnetic fields as natural, whereas upward fields would constitute an anomaly, the researchers argue. Magnetoreceptive animals are known to shut off their internal compasses when encountering weird fields, such as those caused by lightning, which might lead the animals astray. Northern-born humans may similarly take their magnetic sense “offline” when faced with strange, upward-pointing fields.
This explanation “seems plausible,” Hore says, but would need to be tested in an experiment with participants from the Southern Hemisphere.
The brain’s attention to counterclockwise but not clockwise rotations “is something surprising that we don’t really have a good explanation for,” says coauthor Connie Wang, who studies magnetoperception at Caltech. Some people may respond to clockwise rotations, just like some people are left-handed rather than right-handed, or clockwise rotations generate brain activity not captured in the alpha wave signal, she says.
Even accounting for which magnetic changes the brain picks up, researchers still don’t know what our minds might use that information for, Kirschvink says. Another lingering mystery is how, exactly, our brains detect Earth’s magnetic field. According to the researchers, the brain wave patterns uncovered in this study may be explained by sensory cells containing a magnetic mineral called magnetite, which has been found in magnetoreceptive trout as well as in the human brain (SN: 8/11/12, p. 13). Future experiments could confirm or eliminate that possibility.
With this first compelling evidence that humans are subconsciously processing magnetic signals, “we can [try to] identify the brain region it originates from and try to identify the nature of the cells” responsible, says Michael Winklhofer, a magnetoreception researcher at the University of Oldenburg in Germany. “This is really the first step.”

Citations
C.X. Wang et al. Transduction of the geomagnetic field as evidenced from alpha-band activity in the human braineNeuro. Published online March 18, 2019. doi:10.1523/ENEURO.0483-18.2019.
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#68
Ancient sculptors made magnetic figures from rocks struck by lightning
Guatemalan ‘potbelly’ sculptures suggest people knew about magnetism more than 2,000 years ago
BY 
BRUCE BOWER 
8:00AM, APRIL 22, 2019

[Image: 041719_bb_magneticsculpture_feat_rev.jpg][img=719x0]https://www.sciencenews.org/sites/default/files/2019/04/main/articles/041719_bb_magneticsculpture_feat_rev.jpg[/img]
MAGNETIC ANCESTOR  Ancient massive carvings from Guatemala such as this round figure include magnetized areas possibly intended to show the continuing power of deceased ancestors.

People living at least 2,000 years ago near the Pacific Coast of what’s now Guatemala crafted massive human sculptures with magnetized foreheads, cheeks and navels. New research provides the first detailed look at how these sculpted body parts were intentionally placed within magnetic fields on large rocks.
Lightning strikes probably magnetized sections of boulders that were later carved into stylized, rotund figures — known as potbellies — at the Guatemalan site of Monte Alto, say Harvard University geoscientist Roger Fu and his colleagues. Artisans may have held naturally magnetized mineral chunks near iron-rich, basalt boulders to find areas in the rock where magnetic forces pushed back, the scientists say in the June Journal of Archaeological Science. Predesignated parts of potbelly figures — which can stand more than 2 meters tall and weigh 10,000 kilograms or more — were then carved at those spots.

[Image: 041719_bb_magneticsculpture_inline1_370.jpg]
HEADS UP Colossal stone heads from an ancient Guatemalan site contain magnetic fields on the right temple and cheek, spots that apparently held special significance for makers of the sculptures.

R. FU
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Potbellies represented dead but still revered ancestors of high-ranking families, suspects art historian Julia Guernsey of the University of Texas at Austin.  Sculptures that repelled magnetized objects would have been seen as demonstrating the presence and authority of deceased ancestors in rapidly expanding societies (SN: 6/1/13, p. 12), she suggests. Fu’s results also indicate that Mesoamericans attributed special powers to certain body parts, such as the face and midsection, Guernsey adds.
The researchers studied 11 potbelly sculptures, six heads and five bodies, now displayed in a Guatemalan town. At least 127 such sculptures have been found at sites in Mesoamerica, an ancient cultural region that runs from central Mexico through much of Central America.
Handheld sensors confirmed a 1997 report that magnetic signals occurred over the right temple and cheek of three colossal heads from Monte Alto. Sensors also detected magnetism near the navels of four body sculptures. A portable, high-resolution magnetic sensor then precisely mapped magnetic fields on two head and two body sculptures.
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#69
(04-29-2019, 08:42 PM)EA Wrote: Ancient sculptors made magnetic figures from rocks struck by lightning
Guatemalan ‘potbelly’ sculptures suggest people knew about magnetism more than 2,000 years ago
BY 
BRUCE BOWER 
8:00AM, APRIL 22, 2019

[Image: 041719_bb_magneticsculpture_feat_rev.jpg][img=696x0]https://www.sciencenews.org/sites/default/files/2019/04/main/articles/041719_bb_magneticsculpture_feat_rev.jpg[/img]
MAGNETIC ANCESTOR  Ancient massive carvings from Guatemala such as this round figure include magnetized areas possibly intended to show the continuing power of deceased ancestors.



update:
JULY 30, 2019
The Mesoamerican attraction to magnetism
by Peter Reuell, Harvard University
[Image: themesoameri.jpg]Magnetic scans performed on potbelly sculptures from Monte Alto, Guatemala, now housed in La Democracia, Guatemala, revealed for the first time that they were originally magnetized by lightning strikes pre-dating the carving process. Credit: Roger Fu
The purpose of Mesoamerican potbelly statues have been the subject of debate among anthropologists for decades: Are they depictions of the ruling elite? A way to honor dead ancestors? Or perhaps portrayals of women giving birth?

As the various theories wound their way through academic circles, the surprising discovery four decades ago that many of the statues, found in Guatemala, are magnetized in certain spots added a new dimension to those discussions.
And a Harvard study suggests that where those areas show up is no accident.
Led by Assistant Professor of Earth and Planetary Sciences Roger Fu, a team of researchers has shown that artisans carved the figures so that the magnetic areas fell at the navel or right temple—suggesting not only that Mesoamerican people were familiar with the concept of magnetism but also that they had some way of detecting the magnetized spots. The study is described in an April 12 paper published in the Journal of Archaeological Science.
"Our direct observation is that there are magnetic anomalies consistently on certain features of these sculptures," Fu said. "And the question we asked is whether this is consistent with random chance, or does it require some knowledge or some awareness of where those anomalies are?
"There's some chance it could happen randomly, but as we find more and more sculptures that are aligned like this, the smaller than likelihood is," he continued. "In this paper, we looked at four, and we found a less than 1 percent chance that this wasn't intentional."
A close study of the anomalies, Fu said, showed they could only have been caused by one source—lightning.
"All rocks contain magnetic minerals," he said. "If you go outside and pick up any random rock, it is magnetic. It's just very, very weakly magnetic. These rocks are basalts from the highlands of Guatemala, and they happen to contain quite a bit of magnetite, as well as other magnetic minerals."
Rocks typically become magnetized as they cool, and minerals like magnetite, hematite, and iron sulfides become aligned with Earth's magnetic field. While that process can create detectable magnetic fields, Fu said they are usually not even strong enough to move a compass needle.
[Image: 1-themesoameri.jpg]

The sculptures may have represented people's ancestors — and showed signed of being magnetized. Credit: Roger Fu
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The fields found in the statues, however, are far stronger—in some cases nearly four times that of the Earth's magnetic field.

"What happened here is that these rocks were struck by lightning sometime between when they were formed many thousands of years ago, and when they were carved," Fu said. "Because lightning is an electric current, it produces very strong magnetic fields, many orders of magnitude stronger than normal … and we believe the ancient Mesoamerican people were able to detect these anomalies."
It's uncertain exactly how they detected the anomalies, but earlier research had turned up evidence that Mesoamericans may have used lodestones—naturally magnetized rocks—for a variety of purposes.
"In one case, in 1975, people discovered a hematite-rich bar," Fu said. "Its purpose was unknown, and it was broken, but it was clearly very carefully made.
"If you were to tie it on a string or float it on a piece of wood, it actually could act as a compass needle," he added. "If the makers of these sculptures had access to a tool like that, that's one way they could have detected them."
And though the study suggests that ancient Mesoamerican people had knowledge of magnetism and how to detect it, it leaves unanswered the question of why the figures were carved to highlight their magnetism.
"The short answer is we don't have a good idea for the exact reason they did this," Fu said. "There are some hypotheses which are quite intriguing … that involve digging into why we think people made these sculptures.
"Probably the most successful idea is that they might represent some depiction of the ancestors of the ruling elites," he continued. "The idea is: If you have some claim to power, sculptures of your ancestors with strong magnetic anomalies could appear very impressive to your subjects. The word people use in the literature is that there's a performative aspect to these sculptures, so when the sculptures deflected a magnetized stone, it would appear as though there was something alive with it, or some supernatural aspect to it."
Ultimately, Fu said, the study offers key evidence that an understanding of magnetism existed in the Americas far earlier than first believed.
"In the Old World, there was some documentation of magnetism in the Greek world by the sixth century B.C., and the first usable compass wasn't until centuries later in China," he said. "To me, what's really interesting is this is a completely independent discovery. There's a perception that the Old World is the advanced world and transferred all this knowledge to the New one, but we are realizing that they knew a lot, and I think this is one more piece of evidence for that."[/size]


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Study of zircon crystals casts doubt on evidence for early development of magnetic field[/size]


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Journal information: Journal of Archaeological Science[/size]


[size=undefined]https://phys.org/news/2019-07-mesoameric...etism.html[/size]





[size=undefined]JULY 31, 2019
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Microbiologists solve the mystery of the compass needle in magnetic bacteria

by University of Bayreuth

[Image: 5d417ad7912cb.jpg]Superresolution fluorescence microscopy of living cells (above) shows how the MamY protein is arranged in the cell: It follows the strongest curvature of the inner cell surface. Credit: Microscope image: Mauricio Toro-Nahuelpan, Giacomo Giacomelli, Marc Bramkamp
Bacteria of the species Magnetospirillum gryphiswaldense are unicellular organisms that can align their locomotion precisely with the Earth's magnetic field. They owe this ability to tiny magnetite crystals called magnetosomes. In the spiral-shaped bacterial cell, the crystals form a stable, straight chain that acts like a compass needle. Microbiologists at the University of Bayreuth, together with research partners at the Max Planck Institute for Biochemistry in Martinsried and at LMU Munich, have now discovered that the shape and position of the magnetosome chain are largely determined by the protein MamY. In the journal Nature Microbiology they now present their latest findings.

Several animals, such as migratory birds or honey bees, but also certain unicellular organisms, can use the Earth's magnetic field for navigation. While science is still unable to explain this "sixth sense" in animals, it is already partially understood in bacteria. It has long been known that bacteria of the species Magnetospirillum gryphiswaldense are magnetotactic, i.e. they can use the Earth's magnetic field for navigation. Each bacterium forms up to 50 magnetosomes in its cell, which are attached to a thread-like structure. This attachment causes the magnetite crystals not to clump together as a result of their own magnetic pull, but to become lined up, thus assuming the function of a compass needle. This enables the bacteria to follow the orientation of the Earth's magnetic field during their swimming movements and thus reach their preferred habitat, the sediments of water bodies, more quickly.
However, it was a mystery why this flexible chain of magnetosomes took such a stable, linear form—while the bacterial cell assumed a spiral shape. Moreover, short magnetosome chains had been observed in some bacteria, which apparently formed without the already known filamentous structure. The assumption was therefore that there had to be another supporting protein that would help magnetotactic bacteria create their compass needle.
[Image: 5d417aea3a664.jpg]


The schematic illustration shows the magnetosome chain, which acts like a rod magnet and is brought into the correct position parallel to the longitudinal axis of the cell by MamY (red). Credit: Frank Müller

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The research team led by Dr. Frank Müller and Prof. Dr. Dirk Schüler at the University of Bayreuth has now discovered this protein. Experiments with highly sensitive instruments and methods, including super-resolution microscopy and cryo-electron tomography, have shown: The structural protein MamY not only causes the straight-line arrangement of the magnetosome chain, but also places this chain in the bacterial cell in a position optimized for the alignment of the swimming movements with the Earth's magnetic field, i.e. exactly parallel to the longitudinal axis of the cell. In bacteria that do not contain MamY, the magnetite crystals form a chain, but not in a linear form. The compass needle is bent, so to speak, which causes the cells to wobble as they swim. And in bacteria without the known filamentous structure, no chains can be detected at all because the magnetosomes simply clump together.

"All these observations confirm the conclusion: MamY is the key protein that arranges the magnetosome chain in the cell in such a way that the function of a compass needle is perfectly fulfilled. The protein enables the bacteria to navigate optimally," explains Dr. Frank Müller, lead author of the study and scientist at the Department of Microbiology at the University of Bayreuth.
In their publication, the researchers also show how the structural protein MamY succeeds in placing the rod-shaped compass needle in the spiral-shaped bacterial cell. It recognizes the areas where the curvilinear cell surface has the strongest curvature. In doing so, it marks the shortest connection between the two ends of the cell, the so-called "geodetic axis." The magnetosome chain is then anchored here. This enables the bacterium to move along the Earth's magnetic field with high precision.[/size]




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BESSY II sheds light on how the internal compass is constructed in magnetotactic bacteria[/size]


[size=undefined]https://phys.org/news/2019-07-microbiolo...netic.html[/size]


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More information: Mauricio Toro-Nahuelpan et al. MamY is a membrane-bound protein that aligns magnetosomes and the motility axis of helical magnetotactic bacteria, Nature Microbiology (2019). DOI: 10.1038/s41564-019-0512-8
Journal information: Nature Microbiology [/url]

Provided by [url=https://phys.org/partners/university-of-bayreuth/]University of Bayreuth
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#70
~333 meters per second >>> 



[Image: 41467_2019_11381_Fig1_HTML.png?as=webp]



Introduction
https://www.quora.com/The-speed-of-sound...ee-Celsius 

https://answers.yahoo.com/question/index...ccounter=1
Today, the supercomputers have become so powerful that they can easily surpass the performance and capacity of the human brain in processing speed and amount of information storage1,2. However, there exists a giant gap in energy consumption and area efficiency between the human brain and the supercomputers with the supercomputers being at least 1,000,000× worse than the human brain3,4. The emerging era of neuromorphic computing promises to shrink this gap by deploying artificial neural networks (ANNs)5. ANNs mimic the fundamental computing unit of brain i.e., neurons connected to other neurons via synapses. Neuromorphic chips such as TrueNorth6, Loihi7, BrainScaleS8, and SpiNNaker9 are truly impressive advancements in the area of artificial intelligence, however, these chips will still remain overwhelmingly power hungry when scaled up to the full capacity of human brain which has 100 billion neurons connected via 1 quadrillion synapses operating at a miniscule 20 W power. It remains to be seen how the energy efficiency of neuromorphic computing based on conventional devices is improved especially at a time when all three quintessential aspects of Moore’s law of scaling i.e., energy, size, and complexity scaling have practically ended.



AUGUST 1, 2019

Barn owls may hold key to navigation and location

by Pennsylvania State University

[Image: barnowlsmayh.jpg]Split-gated transistor for mimicking the neurobiological doink-headthat mimics sound localization in barn owls. Credit: ennifer McCann & Sarbashis Das, Penn State
The way barn owl brains use sound to locate prey may be a template for electronic directional navigation devices, according to a team of Penn State engineers who are recreating owl brain circuitry in electronics.

"We were already studying this type of circuitry when we stumbled across the Jeffress model of sound localization," said Saptarshi Das, assistant professor of engineering science and mechanics.
The Jeffress model, developed by Lloyd Jeffress in 1948, explains how biological hearing systems can register and analyze small differences in the arrival time of sound to the ears and then locate the sound's source.
"Owls figure out which direction the sound is coming from to within one to two degrees," said Saptarshi Das. "Humans are not that precise. Owls use this ability for hunting especially because they hunt at night and their eyesight isn't all that good."
The ability to use sound to locate relies on the distance between the ears. In barn owls, that distance is quite small, but the brain's circuitry has adapted to be able to discriminate this small difference. If the owl is facing the sound source, then both ears receive the sound simultaneously. If the sound is off to the right, the right ear registers the sound slightly before the left.
However, locating objects by sound is not that simple. The speed of sound is faster than the owl's nerves can function so after the owl brain converts the sound to an electrical pulse, the pulse is slowed down. Then the brain's circuitry uses a lattice of nerves of different lengths with inputs from two ends, to determine which length is where the two signals coincide or arrive at the same time. This provides the direction.
Saptarshi Das and his team have created an electronic circuit that can slow down the input signals and determine the coincidence point, mimicking the working of the barn owl brain.
The researchers, who include Saptarshi Das; Akhil Dodda, graduate student in engineering science and mechanics; and Sarbashis Das, graduate student in electrical engineering, note today in Nature Communications that "the precision of the biomimetic device can supersede the barn owl by orders of magnitude."
The team created a series of split-gate molybdenum sulfide transistors to mimic the coincidence nerve network in the owl's brain. Split-gate transistors only produce output when both sides of the gate match, so only the gate tuned to a specific length will register the sound. The biomimetic circuitry also uses a time-delay mechanism to slow down the signal.

While this proof-of-concept circuit uses standard substrates and device types, the researchers believe that using 2-D materials for the devices would make them more accurate and also more energy efficient, because the number of split-gate transistors could be increased, providing more precise coincidence times. The reduction in power consumption would benefit devices working in the low-power domain.
"Millions of years of evolution in the animal kingdom have ensured that only the most efficient materials and structures have survived," said Sarbashis Das. "In effect, nature has done most of the work for us. All we have to do now is adapt these neurobiological architectures for our semiconductor devices."
"While we are trying to make energy-efficient devices, mammalian computing backed by natural selection has necessitated extreme energy-efficiency, which we are trying to mimic in our devices," said Dodda.
However, having only the direction will not provide the location of the sound source. To actually navigate or locate, a device would need to know the height of the sound source as well. Saptarshi Das noted that height is a property of the intensity of the sound and the researchers are working on this aspect of the problem.
"There are several animals that have excellent sensory processing for sight, hearing and smell," said Saptarshi Das. "Humans are not the best at these."
The team is now looking at other animals and other sensory circuitry for future research. While existing research in the field of neuromorphic computing focuses on mimicking the intellectual capacity of the human brain, this work sheds light on an alternate approach by replicating the super sensors of the animal kingdom. Saptarshi Das considers this a paradigm change in this field.




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Internally coupled ears enable directional hearing in animals[/size]



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More information: Nature CommunicationsDOI: 10.1038/s41467-019-11381-9
Journal information: Nature Communications [/url]

Provided by 
Pennsylvania State University
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[size=undefined]https://techxplore.com/news/2019-08-barn-owls-key.html[/size]



Right where Eye Left Leaved off>>>(~33.3 degrees)

Leaves both with and without insects strongly reflect back the sound if it comes from straight ahead (i.e., from angles smaller than 30 degrees). When a bat approaches from these angles, it cannot find its prey as strong echoes from the leaves mask the echoes from the insect. But Geipel and colleagues found that if the sound originates from oblique angles greater than 30 degrees,(~33.3 degrees) the sound is reflected away from the source and leaves act like a mirror, just as a lake reflects the surrounding forest at dusk or dawn. The approach angle makes a resting insect detectable.

AUGUST 1, 2019

Bats use leaves as mirrors to find prey in the dark

by Smithsonian Tropical Research Institute

[Image: batsuseleave.jpg]Portrait of Micronycteris microtis. Credit: Inga Geipel
On moonless nights in a tropical forest, bats slice through the inky darkness, snatching up insects resting silently on leaves—a seemingly impossible feat. New experiments at the Smithsonian Tropical Research Institute (STRI) show that by changing their approach angle, the echolocating leaf-nosed bats can use this sixth sense to find acoustically camouflaged prey. These new findings, published in Current Biology, have exciting implications for the evolution of predator-prey interactions.

"For many years it was thought to be a sensory impossibility for bats to find silent, motionless prey resting on leaves by echolocation alone," said Inga Geipel, Tupper Postdoctoral Fellow at STRI. Geipel's team discovered how the bats achieve the impossible. By combining evidence from experiments using a biosonar device to create and measure artificial signals, with evidence from high-speed video observations of bats as they approach prey, the importance of the approach angle was revealed.
Bats have a superpower humans do not share: they flood an area with sound waves and then use information from the returning echoes to navigate through the environment. Leaves reflect echolocation signals strongly, masking the weaker echoes from resting insects. So in the thick foliage of a tropical forest, echoes from the leaves may act as a natural cloaking mechanism for the insects, known as acoustic camouflage.
To understand how bats overcome acoustic camouflage and seize their prey, the researchers aimed sound waves at a leaf with and without an insect from more than 500 positions in order to create a full, three-dimensional representation of the echoes. At each position, they calculated the intensity of the echoes for five different frequencies of sound that represent the frequencies of a bat's call.
[Image: 1-batsuseleave.jpg]


This bat gleans insects from leaves. Inga Geipel and colleagues discovered that by approaching a leaf at an oblique angle, it can use its echolocation system to detect stationary insects in the dark. Credit: Inga Geipel

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Leaves both with and without insects strongly reflect back the sound if it comes from straight ahead (i.e., from angles smaller than 30 degrees). When a bat approaches from these angles, it cannot find its prey as strong echoes from the leaves mask the echoes from the insect. But Geipel and colleagues found that if the sound originates from oblique angles greater than 30 degrees, the sound is reflected away from the source and leaves act like a mirror, just as a lake reflects the surrounding forest at dusk or dawn. The approach angle makes a resting insect detectable.
Based on these experiments, Geipel and colleagues predicted that bats should approach resting insects on leaves from angles between 42 and 78 degrees, the optimal angles for discerning whether a leaf has an insect on it or not.
Next, Geipel recorded actual bats at STRI's Barro Colorado Island research station in Panama as they approached insects positioned on artificial leaves. Using recordings from two high-speed cameras, she reconstructed the three-dimensional flight paths of the bats as they approached their prey and determined their positions. She discovered that, as predicted, almost 80 percent of the approach angles were within the range of angles that makes it possible for the bats to distinguish insect from leaf.
"This study changes our understanding of the potential uses of echolocation," Geipel said. "It has important implications for the study of predator-prey interactions and for the fields of sensory ecology and evolution."[/size]




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When does noise become a message?[/size]



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More information: Geipel, I., Steckel, J., Tschapka, M., et al. 2019. Bats actively use leaves as specular reflectors to detect acoustically camouflaged prey. Current Biologydoi.org/10.1016/j.cub.2019.06.076
Journal information: Current Biology 

Provided by [url=https://phys.org/partners/smithsonian-tropical-research-institute/]Smithsonian Tropical Research Institute
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[size=undefined]https://phys.org/news/2019-08-mirrors-prey-dark.html[/size]
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#71
SEPTEMBER 4, 2019 REPORT
Evidence suggests birds use eye proteins and magnetite-based receptors to navigate
by Bob Yirka , Phys.org
[Image: migratingbir.jpg]Credit: CC0 Public Domain
A pair of researchers from Goethe-Universität Frankfurt and Max von Laue-Straße 13 report that research by others has shown that there are two main physical attributes birds use to navigate. In their paper published in Journal of the Royal Society Interface, two researchers outline the current state of the study of navigation in birds and what they found.

Some birds have demonstrated extremely sophisticated navigational abilities, flying thousands of miles during migrations—yet, scientists still do not know how they do it. In this new effort, husband and wife research team Roswitha and Wolfgang Wiltschko outline research that has been conducted by several groups in the field and what has been found. They also note that one major part of the process is still a mystery—how the bird brain processes the information it receives and translates it into accurate navigation.
The researchers begin their report by noting that several studies have shown that birds navigate long distances by making use of the Earth's magnetic field. What has been difficult has been figuring out how they do so. Most in the field believe birds use two attributes of the magnetic field; the direction of field lines and their intensity. The Wiltschkos highlight several studies that have led to evidence of radical pair processing in the eyes via a special protein—allowing the birds to actually "see" the magnetic field as they fly. As for sensing and gauging the intensity of the field, they cite several reports that have led to suggestions that there are bits of metal (magnetite) embedded in tissue that "feel" the magnetism and nerves that carry the information to the brain. They note that there is not a consensus as of yet regarding where the embedded metal may be, but some have suggested it likely resides somewhere in the beak.
What is still a mystery, however, is how and in what parts of the brain navigation is carried out. The Wiltschkos point out that some research has led to theories that suggest that the hippocampus is heavily involved. Generally known for its role in memory, the birds may be adding navigational information to the geographic information they bank as they grow older. The researchers also note that most in the field believe that birds use a different form of navigation than other mammals, such as fish and reptiles.




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News about the light-dependent magnetic compass of birds



[b]More information:[/b] Roswitha Wiltschko et al. Magnetoreception in birds, Journal of The Royal Society Interface (2019). DOI: 10.1098/rsif.2019.0295
[b]Journal information:[/b] Journal of the Royal Society Interface



https://phys.org/news/2019-09-evidence-b...based.html


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Bird flocks and magnetic systems have been studied before, but mostly by biologists and physicists working in different buildings. Now we know that the two share something in common, and from this, new connections may emerge.



Birds Of A Feather Flock Like A Magnetic System
Some scientists look into the sky for stars; others look for starlings.

birdofafeather2.jpg

Composite image by Yuen Yiu, Staff Writer



PHYSICS

Thursday, September 22, 2016 - 15:45

Yuen Yiu, Staff Writer



(Inside Science) -- An interdisciplinary team of physicists, biologists and biophysicists has developed a model that can imitate the mesmerizing patterns of starling flocks. By drawing an unlikely parallel between starling flocks and magnetic systems, the scientists were able to describe this vastly complicated biological system using only a few physical equations.
All sciences can be boiled down to the observation and prediction of patterns. Sometimes patterns that seem totally unrelated resemble each other in some way, like human eyes and nebulae, or hurricanes and galaxies. Sometimes these things have nothing in common except the associations we contrive, but sometimes they actually do. For example, fractal patterns, which can be found in tree roots, river branches and lightning strikes, all share a similar appearance and can also be represented by a common physical principle.
"The difficult thing is figuring out how to do a proper study to test the extent of these analogies," said Frederic Bartumeus, an expert in movement ecology from the Centre for Advanced Studies of Blanes in Spain. "To see how accurate one can describe a biological system using concepts from statistical physics for example."
This is exactly what the scientists from École Normale Supérieure in France and Institute for Complex Systems in Italy have done. In their recent paper published in [i]Nature Physics[/i] in August, a team led by physicist Thierry Mora has successfully modeled how starling flocks behave by modifying existing theories on magnetic systems.

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[img=480x0]https://www.insidescience.org/sites/default/files/images/articles/inline-images/inline-spinwave.gif[/img]


The overlaid white arrows illustrate how changes ripple through a lattice of magnetic dipoles. Mora's team developed a similar but much more sophisticated 3-D mathematical model to describe the starling flocks.

Yuen Yiu, Staff Writer

Composite image based on gif and background image courtesy of Jonathan Flynn and Thierry Mora.

A flock of tiny little magnets
Largely driven by the demand for better computing and data storage devices, for decades physicists have studied how to manipulate magnetic materials for practical uses. But physicists being physicists, it is not enough just to know how; they also needed to know why.
They have learned that inside a ferromagnet -- like a fridge magnet -- there are billions and trillions of individual magnetic dipoles. Each dipole is itself essentially a tiny magnet, and they all have to line up for the big magnet to work. So the physicists developed and tested models and theories on what happens at microscopic scales inside magnets -- how individual dipoles behave, how each of them interacts with their neighbors and how these interactions between these tiny magnets affect the big magnet.
Similar to a magnetic dipole, an individual starling adjusts itself depending on its neighbors. While there have been other parallel efforts that have investigated flocking starlings, Mora's team has taken a different approach to the problem -- by studying the flocks using theories originally intended for magnetic systems.  
By carefully modifying theories of magnetic dipole interactions, they were able to develop a model that can accurately describe the behavior of flocking starlings.
Essentially the model simulates the interactions between neighboring individuals within the group. It not only predicts the movements of individual starlings, but more importantly the time it takes for an individual's adjustment to affect the movement of the entire flock.
The bigger picture
"People have also looked into collective motion at a cellular scale, for example in biological studies like tissue repairs," said Mora. "The same class of models have been proposed to describe those motions, … basically any system where agents move by themselves."
A better understanding of collective systems in general can have an impact on a broad range of subjects, from crowd control to bacteria growth and even the design of future self-propelled medical nanobots.
"Of course there will be some conditions for what kind of system this model can be applied," said Bartumeus,"but to have any kind of transferrable knowledge among different biological systems, that's already magic for a biologist."
Bird flocks and magnetic systems have been studied before, but mostly by biologists and physicists working in different buildings. Now we know that the two share something in common, and from this, new connections may emerge.
"Sometimes it's difficult to find physicists who are willing to study biology, or biologists who are interested in physics," said Bartumeus. "There's a pool of theories in physics that can be used to describe collective motion in biology, and this research has just opened another door."
 
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#72
SEPTEMBER 12, 2019
Why do birds migrate at night?
[Image: whydobirdsmi.jpg]Credit: SMU
It was a puzzle about birds.

Migratory birds are known to rely on Earth's magnetic field to help them navigate the globe. And it was suspected that a protein called cryptochrome, which is sensitive to blue light, was making it possible for birds to do this.
Yet many of these animals are also known to migrate at night when there isn't much light available. So it wasn't clear how cryptochrome would function under these conditions in birds.
A new study led by UT Southwestern Medical Center in collaboration with SMU (Southern Methodist University), though, may have figured out the answer to that puzzle.
Researchers found that cryptochromes from migratory birds have evolved a mechanism that enhances their ability to respond to light, which can enable them to sense and respond to magnetic fields.
"We were able to show that the protein cryptochrome is extremely efficient at collecting and responding to low levels of light," said SMU chemist Brian D. Zoltowski, who was one of the lead authors of a new study on the findings. "The result of this research is that we now understand how vertebrate cryptochromes can respond to very low light intensities and function under night time conditions."
The study was published in the journal PNAS in September.
Cryptochromes are found in both plants and animals and are responsible for circadian rhythms in various species. In birds, scientists were specifically focused on learning more about an unusual eye protein called CRY4, which is part of a class of cryptochromes.

[Image: 1-whydobirdsmi.jpg]
(From left) UT Southwestern Medical Center research specialist Yogarany Chelliah, Dr. Joseph Takahashi, and SMU's Dr. Brian Zoltowski. Credit: SMU (Southern Methodist University), Kim Leeson
The lab of Joseph Takahashi, a circadian rhythms expert at UT Southwestern Medical Center, worked with other UT Southwestern scientists to purify and solve the crystal structure of the protein—the first atomic structure of a photoactive cryptochrome molecule from a vertebrate. The lab of Brian Zoltowski, an expert in blue-light photoreceptors, studied the efficiency of the light-driven reactions—identifying a pathway unique to CRY4 proteins that facilitates function under low light conditions.

"Although in plants and insects, cryptochromes are known to be photoactive, which means they react to sunlight. Among vertebrates much less is known, and the majority of vertebrate cryptochromes do not appear to be photoactive," said Takahashi, chairman of neuroscience at UT Southwestern and an investigator with Howard Hughes Medical Institute. "This photosensitivity and the possibility that CRY4 is affected by the magnetic field make this specific cryptochrome a very interesting molecule."
Researchers took a sample of the CRY4 from a pigeon and grew crystals of the protein. They then exposed the crystals to x-rays, making it possible for them to map out the location of all the atoms in the protein.
And while pigeons are not night-migratory songbirds, the sequences of their CRY4 proteins are very similar, the study noted.
"These structures allow us to visualize at the atomic scale how these proteins function and understand how they may use blue-light to sense magnetic fields," said Zoltowski, associate professor of chemistry at SMU's Dedman College of Humanities & Sciences. "The new structures also provide the first atomic level detail of how these proteins work, opening the door for more detailed studies on cryptochromes in migratory organisms."
In the study, researchers discovered unusual changes to key regions of the protein structure that can enhance their ability to collect light from their environment.
"Cryptochromes work by absorbing a photon of light, which causes an electron to move through a sequence of amino acids. These amino acids typically consist of a chain of 3 or 4 sites that act as a wire that electrons can flow through," explained Zoltowski. "But in pigeons, it was identified that this chain may be extended to contain 5 sites."
This mutation of the electron chain in pigeons makes cryptochrome less dependent on a bird's environment having a lot of light for the protein to be activated.
"Birds have evolved a mechanism to enhance the efficiency. So even when there is very little light around, they have enough signal generated to migrate," Zoltowski said.




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Migratory birds eye-localized magnetoreception for navigation



[b]More information:[/b] Brian D. Zoltowski et al, Chemical and structural analysis of a photoactive vertebrate cryptochrome from pigeon, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1907875116
[b]Journal information:[/b] Proceedings of the National Academy of Sciences [/url]

Provided by [url=https://phys.org/partners/southern-methodist-university/]Southern Methodist University



https://phys.org/news/2019-09-birds-migrate-night.html
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JANUARY 9, 2020
Scientists show that the eyes can measure hearing
by Jim Barlow, University of Oregon
[Image: 7-eye.jpg]Credit: CC0 Public Domain
In 1998, University of Oregon researcher Avinash Singh Bala was working with barn owls in an Institute of Neuroscience lab when the birds' eyes caught his attention.

The usual research done in the lab, led by Terry Takahashi, explores, at a fundamental level, how barn owls process sounds, with the idea that such knowledge could lead to improved hearing devices for people.
But those eyes. Every time the owls heard an unexpected sound, their eyes dilated.
"So, we asked, might this work in humans?" Bala said. "We thought, if so, it would be a great way to assess hearing in people who cannot respond by pushing a button, raising a hand or talking, such as babies, older children with developmental deficits and adults who are suffering from a debilitating disorder or are too sick to respond."
Over the next decade, Bala and Takahashi, as free time outside their primary research allowed, pursued ideas on how to use the eyes as a window to hearing. They experimented, finding similar involuntary dilation in humans. They tweaked a possible approach, aiming for sensitivity that might equal that achieved with traditional tone-and-response testing.
"We presented early data analyses at conferences, and there was a lot of resistance to the idea that by looking at an involuntary response we could get results as good as button-press data."
Last month, the two UO neuroscientists published a freely accessible paper in the Journal of the Association for Research in Otolaryngology that solidifies their case. They used eye-tracking technology simultaneously as they conducted traditional hearing exams with 31 adults in a quiet room.
Dilation was monitored for about three seconds as participants stared at a dot on a monitor while a tone was played. To avoid being fooled by pupil reactions generated by pushing a response button, subjects' responses were delayed until the dot was replaced by a question mark, when eye-tracking stopped.
Levels of dilation seen throughout the testing directly reflected the participants' subsequent push-button responses on whether or not a tone was heard. That, Bala said, allowed his team, which also included former doctoral student and co-author Elizabeth Whitchurch, "to see and establish causality."
"This study is a proof of concept that this is possible," Bala said. "The first time we tested a human subject's pupil response was in 1999. We knew it could work, but we had to optimize the approach for capturing the detection of the quietest sounds."
Takahashi said the initial discovery was completely accidental.
"If we hadn't been working with owls, we wouldn't have known about this possible human diagnostic technique," he said. "This is a really good example of how animal-based research can benefit advances in human diagnostics."
The testing in the newly published research, funded initially by internal grants, was done using conventional, commercially available hearing and eye-tracking technologies.
Bala and Takahashi are now collaborating with Dare Baldwin, a professor of psychology, on developing their own technology for testing with babies. The effort is being supported by a 2015 Incubating Interdisciplinary Initiatives award from the Office of the Vice President for Research and Innovation and a recent grant from the University Venture Development Fund.
Bala and Takahashi also have launched a UO spinout, Perceptivo LLC, to pursue development of an infant-hearing assessment.




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Barn owls found to suffer no hearing loss as they age



[b]More information:[/b] Avinash D. S. Bala et al. Human Auditory Detection and Discrimination Measured with the Pupil Dilation Response, Journal of the Association for Research in Otolaryngology (2019). DOI: 10.1007/s10162-019-00739-x
[b]Journal information:[/b] Journal of the Association for Research in Otolaryngology [/url]

Provided by 
University of Oregon 





DECEMBER 17, 2019
Newly discovered retinal structure may enhance vision for some birds
by Emil Venere, Purdue University
[Image: 27-newlydiscove.jpg]These microscopy images show a newly discovered retinal structure, called the MMOD-complex, in small sit-and-wait songbirds called flycatchers. Credit: Purdue University image/ Esteban Fernandez-Juricic and Luke Tyrrell
A newly discovered retinal structure in the eyes of certain kinds of songbirds might help the animals find and track insect prey more easily.

The foundation of avian vision rests on cells called cone and rod photoreceptors. Most birds have four cone photoreceptors for color vision, a fifth cone for non-color-related tasks, and a rod for night vision. Each cone photoreceptor cell contains a spherical structure called an "oil droplet," which filters light before it is converted to electrical signals by the visual pigments, enhancing color discrimination.
However, the researchers have discovered a never-before-seen type of cone structure in the retina of a group of small songbirds, called flycatchers. Instead of an oil droplet, it contains a high- energy-producing cellular structure called "megamitochondria" surrounded by hundreds of small, orange-colored droplets. The researchers named this novel cellular structure a megamitochondria-small oil droplet complex, or MMOD-complex.
The discovery, made at Purdue University, is detailed in a paper that appeared in the journal Scientific Reports, as part of a collaboration with the State University of New York at Plattsburgh, the University of Wisconsin-Madison, and the University of California, Davis.
The researchers studied this retinal structure using light microscopytransmission electron microscopy and a technique called microspectrophotometry, which measures the wavelengths of light that these structures absorb the most. The MMOD-complex works as long-pass filters, letting light with wavelengths longer the 565 nanometers—or yellow, orange and red—pass through, and absorbing the shorter wavelengths of green, blue and violet.
Traditional cones were present throughout the retina of these flycatchers, and their density decreased moving away from the center toward the periphery. However, the MMOD-complex photoreceptors were present only in the central region of the retina, an arrangement that could help birds detect flying insects, said Esteban Fernandez-Juricic, a professor of biological sciences at Purdue.
"The retina of flycatchers, which are sit-and-wait predatory birds, evolved a novel cellular structure in a photoreceptor that may allow them to detect, track and capture fast-moving prey, like insects," he said.
The paper's lead author was Luke Tyrrell, a former Purdue doctoral student and now an assistant professor of biological science at SUNY Plattsburgh.
"This new cone organelle has not been reported before in this form in any other vertebrate retina and may allow these birds to see their world in a different way from other animals," Tyrrell said.




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Disruption of glucose transport to rods and cones shown to cause vision loss in retinitis pigmentosa



[b]More information:[/b] Luke P. Tyrrell et al. A novel cellular structure in the retina of insectivorous birds, Scientific Reports (2019). DOI: 10.1038/s41598-019-51774-w
[b]Journal information:[/b] Scientific Reports 

Provided by [url=https://phys.org/partners/purdue-university/]Purdue University



https://phys.org/news/2019-12-newly-reti...birds.html




[Image: falconsseepr.jpg]
Falcons see prey at speed of Formula 1 car
Extremely acute vision and the ability to rapidly process different visual impressions—these two factors are crucial when a peregrine falcon bears down on its prey at a speed that easily matches that of a Formula 1 racing ...


PLANTS & ANIMALS
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Magnetite (Fe3O4) is a common mineral with strong magnetic properties that were documented in ancient Greece. Initially, it was used mainly in compasses, and later in many other devices, such as data recording tools. It is also widely applied to catalytic processes. Even animals benefit from the properties of magnetite in detecting magnetic fields—for example, magnetite in the beaks of birds may aid them in navigation.


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MAY 27, 2020
New type of coupled electronic-structural waves discovered in magnetite

[Image: newtypeofcou.jpg]Illustration of the newly discovered charge fluctuations in the trimeron order of magnetite triggered by a laser beam. Credit: Source: Ambra Garlaschelli and MIT
An international team of scientists uncovered exotic quantum properties hidden in magnetite, the oldest magnetic material known to mankind. The study reveals the existence of low-energy waves that indicate the important role of electronic interactions with the crystal lattice. This is another step toward fully understanding the metal-insulator phase transition mechanism in magnetite, and in particular, to learn about the dynamical properties and critical behavior of this material in the vicinity of the transition temperature.

Magnetite (Fe3O4) is a common mineral with strong magnetic properties that were documented in ancient Greece. Initially, it was used mainly in compasses, and later in many other devices, such as data recording tools. It is also widely applied to catalytic processes. Even animals benefit from the properties of magnetite in detecting magnetic fields—for example, magnetite in the beaks of birds may aid them in navigation.
Physicists are also interested in magnetite because around a temperature of 125 K, it shows an exotic phase transition, named after the Dutch chemist Verwey. This Verwey transition was also the first phase metal-to-insulator transformation observed historically. During this extremely complex process, the electrical conductivity changes by as much as two orders of magnitude and a rearrangement of the crystal structure takes place. Verwey proposed a transformation mechanism based on the location of electrons on iron ions, which leads to the appearance of a periodic spatial distribution of Fe2+ and Fe3+ charges at low temperatures.
In recent years, structural studies and advanced calculations have confirmed the Verwey hypothesis, while revealing a much more complex pattern of charge distribution (16 non-equivalent positions of iron atoms) and proving the existence of orbital order. The fundamental components of this charge-orbital ordering are polarons—quasiparticles formed as a result of a local deformation of the crystal lattice caused by the electrostatic interaction of a charged particle (electron or hole) moving in the crystal. In the case of magnetite, the polarons take the form of trimerons, complexes made of three iron ions, where the inner atom has more electrons than the two outer atoms.
The new study, published in the journal Nature Physics, was carried out by scientists from many leading research centers around the world. Its purpose was to experimentally uncover the excitations involved in the charge-orbital order of magnetite and describe them by means of advanced theoretical methods. The experimental part was performed at MIT (Edoardo Baldini, Carina Belvin, Ilkem Ozge Ozel, Nuh Gedik); magnetite samples were synthesized at the AGH University of Science and Technology (Andrzej Kozlowski); and the theoretical analyses were carried out in several places: the Institute of Nuclear Physics of the Polish Academy of Sciences (Przemyslaw Piekarz, Krzysztof Parlinski), the Jagiellonian University and the Max Planck Institute (Andrzej M. Oles), the University of Rome "La Sapienza" (Jose Lorenzana), Northeastern University (Gregory Fiete), the University of Texas at Austin (Martin Rodriguez-Vega), and the Technical University in Ostrava (Dominik Legut).

"At the Institute of Nuclear Physics of the Polish Academy of Sciences, we have been conducting studies on magnetite for many years, using the first-principles calculation method," explains Prof. Przemyslaw Piekarz. "These studies have indicated that the strong interaction of electrons with lattice vibrations (phonons) plays an important role in the Verwey transition."
The scientists at MIT measured the optical response of magnetite in the extreme infrared for several temperatures. Then, they illuminated the crystal with an ultrashort laser pulse (pump beam) and measured the change in the far-infrared absorption with a delayed probe pulse. "This is a powerful optical technique that enabled us to take a closer view at the ultrafast phenomena governing the quantum world," says Prof. Nuh Gedik, head of the research group at MIT.
The measurements revealed the existence of low-energy excitations of the trimeron order, which correspond to charge oscillations coupled to a lattice deformation. The energy of two coherent modes decreases to zero when approaching the Verwey transition—indicating their critical behavior near this transformation. Advanced theoretical models allowed them to describe the newly discovered excitations as a coherent tunneling of polarons. The energy barrier for the tunneling process and other model parameters were calculated using density functional theory (DFT), based on the quantum-mechanical description of molecules and crystals. The involvement of these waves in the Verwey transition was confirmed using the Ginzburg-Landau model. Finally, the calculations also ruled out other possible explanations for the observed phenomenon, including conventional phonons and orbital excitations.
"The discovery of these waves is of key importance for understanding the properties of magnetite at low temperatures and the Verwey transition mechanism," write Dr. Edoardo Baldini and Carina Belvin of MIT, the lead authors of the article. "In a broader context, these results reveal that the combination of ultrafast optical methods and state-of-the-art calculations makes it possible to study quantum materials hosting exotic phases of matter with charge and orbital order."
The obtained results lead to several important conclusions. First, the trimeron order in magnetite has elementary excitations with a very low energy, absorbing radiation in the far-infrared region of the electromagnetic spectrum. Second, these excitations are collective fluctuations of charge and lattice deformations that exhibit critical behavior and are thus involved in the Verwey transition. Finally, the results shed new light on the cooperative mechanism and dynamical properties that lie at the origin of this complex phase transition.
"As for the plans for the future of our team, as part of the next stages of work we intend to focus on conducting theoretical calculations aimed at better understanding the observed coupled electronic-structural waves," concludes Prof. Piekarz.




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Physicists use extreme infrared laser pulses to reveal frozen electron waves in magnetite



[b]More information:[/b] Edoardo Baldini et al, Discovery of the soft electronic modes of the trimeron order in magnetite, Nature Physics (2020). DOI: 10.1038/s41567-020-0823-y
[b]Journal information:[/b] Nature Physics [/url]

Provided by [url=https://phys.org/partners/polish-academy-of-sciences/]Polish Academy of Sciences


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Quote:[color=var(--yt-endpoint-visited-color, var(--yt-spec-text-primary))][color=var(--ytd-video-primary-info-renderer-title-color, var(--yt-spec-text-primary))]Dog makes 57-mile journey to old home
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[color=var(--yt-spec-text-secondary)]2,924 views[/color]
[color=var(--yt-spec-text-secondary)]•Jul 17, 2020[/color]

[color=var(--yt-endpoint-visited-color, var(--yt-spec-text-primary))]KTNV Channel 13 Las Vegas

[color=var(--yt-spec-text-primary)]A yellow lab from Missouri reunited with his owner after she moved 60 miles away from home. As "Cleo" tried to find her way home, she ended up back at the home where her owners lived 2 years ago. Her owners checked her microchip and says they were shocked she was able to make it there.[/color]
[/color]
They say you can never go home...

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JULY 20, 2020 REPORT
Dogs may use Earth's magnetic field to navigate
by Bob Yirka , Phys.org
[Image: dog.jpg]Credit: Unsplash/CC0 Public Domain
A team of researchers from Czech University of Life Sciences, Virginia Tech and Barry University has found evidence that suggests dogs may use Earth's magnetic field as a navigational aid. In their paper in the eLife Sciences initiative, the group describes their study of dog navigation and what they learned from it.

Prior research has shown that dogs tend to orient themselves in a north-south position when urinating—a finding that suggests they may have the ability to sense the Earth's magnetic field. In this new effort, the researchers conducted two experiments to further study magnetic field sensing in dogs and whether they use it for navigation.
The two experiments were essentially the same—they both involved attaching GPS sensors to multiple dogs, taking them out into a natural environment and releasing to run about. In all cases, the dogs soon returned to the person who had released them. The only difference in the experiments was the number of dogs involved—in the first, it was just four, and in the second it was 27.
In studying the routes the dogs took, both when heading out on an expedition and when returning, the researchers found they used one of two types of return. The first was called tracking, which meant a dog made its way back by following the same path it had taken out—presumably using its nose. The team called the other type of return scouting—because the dogs followed an unfamiliar path to get back to where they had begun their adventure. The researchers also found something else—for a large percentage of the scouting returns, the dogs first engaged in an odd behavior. They ran north-south along a 20-meter length a few times before heading back to their starting point—doing so appeared to help the dogs get their bearings, as those that did it were more efficient in their return.
The researchers suggest the north-south running is evidence of the dogs using the magnetic field to orient themselves in unfamiliar surroundings, which in turn helps them find their way home. Further testing involved the owner hiding as the dog made its trek, testing wind direction and speed and noting the gender of the dog. No other factors made a difference in improving navigational efficiency, further supporting the idea that the dogs were able to use the Earth's magnetic field to navigate.




Explore further
Researchers find dogs sensitive to small variations in Earth's magnetic field



[b]More information:[/b] Kateřina Benediktová et al. Magnetic alignment enhances homing efficiency of hunting dogs, eLife (2020). DOI: 10.7554/eLife.55080
[b]Journal information:[/b] eLife



https://phys.org/news/2020-07-dogs-earth...field.html
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#76
SEPTEMBER 14, 2020
Animals' magnetic 'sixth' sense may come from bacteria, new paper suggests
[Image: 5758903a7a8fb.jpg]Credit: CC0 Public Domain
A University of Central Florida researcher is co-author of a new paper that may help answer why some animals have a magnetic 'sixth' sense, such as sea turtles' ability to return to the beach where they were born.

The question is one that has been unresolved despite 50 years of research.
"The search for a mechanism has been proposed as one of the last major frontiers in sensory biology and described as if we are 'searching for a needle in a hay stack,'" says Robert Fitak, an assistant professor in UCF's Department of Biology, part of UCF's College of Sciences.
Fitak and researchers in the United Kingdom and Israel recently authored an article in Philosophical Transactions of the Royal Society B that proposes a hypothesis that the magnetic sense comes from a symbiotic relationship with magnetotactic bacteria.
Magnetotactic bacteria are a special type of bacteria whose movement is influenced by magnetic fields, including the Earth's.
Animals that sense Earth's magnetic field include sea turtles, birds, fish and lobsters. Sea turtles, for example, can use the ability for navigation to return to the beach where they were born.
Learning how organisms interact with magnetic fields can improve humans' understanding of how to use Earth's magnetic fields for their own navigation purposes. It can also inform ecological research into the effects of human modifications of the magnetic environment, such as constructing power lines, on biodiversity. Research into the interaction of animals with magnetic fields can also aid the development of therapies that use magnetism for drug delivery.
In the article, the researchers review the arguments for and against the hypothesis, present evidence published in support that has arisen in the past few years, as well as offer new supportive evidence of their own.
Their new evidence comes from Fitak, who mined one of the largest genetic databases of microbes, known as the Metagenomic Rapid Annotations using Subsystems Technology database, for the presence of magnetotactic bacteria that had been found in animal samples.
Previous microbial diversity studies have often focused on large patterns of the presence or absence of bacteria phyla in animals rather than specific species, Fitak says.
"The presence of these magnetotactic bacteria had been largely overlooked, or 'lost in the mud' amongst the massive scale of these datasets," he says.
Fitak found, for the first time, that magnetotactic bacteria are associated with many animals, including a penguin species, loggerhead sea turtles, bats and Atlantic right whales.
For instance, Candidatus Magnetobacterium bavaricum regularly occurred in penguins and loggerhead sea turtles, while Magnetospirillum and Magnetococcus regularly occurred in the mammal species brown bats and Atlantic right whales.
Fitak says researchers still don't know where in the animal that the magnetotactic bacteria would live, but it could be that they would be associated with nervous tissue, like the eye or brain.
"I'm working with the co-authors and local UCF researchers to develop a genetic test for these bacteria, and we plan to subsequently screen various animals and specific tissues, such as in sea turtles, fish, spiny lobsters and birds," Fitak says.
Before joining UCF in 2019, Fitak worked for more than four years as a postdoctoral researcher at Duke University performing experiments to identify genes related to a magnetic sense in fish and lobsters using modern genomic techniques.
He says the hypothesis that animals use magnetic bacteria in a symbiotic way to gain a magnetic sense warrants further exploration but still needs more evidence before anything conclusive can be stated.




Explore further
New study finds genetic evidence that magnetic navigation guides loggerhead sea turtles



[b]More information:[/b] Eviatar Natan et al, Symbiotic magnetic sensing: raising evidence and beyond, Philosophical Transactions of the Royal Society B: Biological Sciences (2020). DOI: 10.1098/rstb.2019.0595
[b]Journal information:[/b] Philosophical Transactions of the Royal Society B [/url]

Provided by [url=https://phys.org/partners/university-of-central-florida/]University of Central Florida



https://phys.org/news/2020-09-animals-ma...paper.html
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Fresh concept for an old thread.
The cat came back but how was it lead?




Quote:“If there were a direct way to switch the magnetic properties of a solid-state memory with an electric field, this would be a breakthrough.”




“Polarization is when the positive and negative charges in the crystal are displaced a little bit, with respect to each other,” Professor Pimenov said.
“This would be easy to achieve with an electric field — but due to the magnetoelectric effect, this is also possible using a magnetic field.”
The stronger the magnetic field, the stronger its effect on electrical polarization.
“The relationship between polarization and magnetic field strength is approximately linear, which is nothing unusual,” the physicist said.
“What is remarkable, however, is that the relationship between polarization and the direction of the magnetic field is strongly non-linear.”
“If you change the direction of the magnetic field a little bit, the polarization can completely tip over.”
“This is a new form of the magnetoelectric effect, which was not known before.”


New Type of Magnetoelectric Effect Discovered
Sep 15, 2020 by News Staff / Source
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[b]Even small changes in the direction of the magnetic field can switch the electrical properties of a paramagnetic rare-earth material — the holmium-doped langasite (HoxLa3-xGa5SiO14) — to a completely different state, according to new research published in the journal [i]npj Quantum Materials[/i].[/b]
[Image: image_8850-Langasite.jpg]


Crystal structure and magnetism in rare-earth langasite: (a) the distorted Kagome lattice of the rare-earth ions in R3Ga5SiO14; about 1.5% of the rare-earth sites (orange) are occupied by the holmium ions; the unit cell is shown by thin solid lines; (b) experimental and theoretical magnetization curves of HoxLa3−xGa5SiO14 (x = 0.043) in external magnetic fields parallel to three crystallographic axes and at T = 5 K. Symbols – experiment, solid lines – model accounting for a ground Ho3+ quasidoublet and a Van-Vleck contribution of excited crystal-field states. The inset shows the local magnetic moments of Ho-ions in the saturation regime. Image credit: Weymann [i]et al[/i], doi: 10.1038/s41535-020-00263-9.

“Whether the electrical and magnetic properties of a crystal are coupled or not depends on the crystal’s internal symmetry,” said co-lead author Professor Andrei Pimenov, a researcher in the Institute of Solid State Physics at TU Wien.
“If the crystal has a high degree of symmetry, for example, if one side of the crystal is exactly the mirror image of the other side, then for theoretical reasons there can be no magnetoelectric effect.”
“The crystal structure of the holmium-doped langasite is so symmetrical that it should actually not allow any magnetoelectric effect,” he added.
“And in the case of weak magnetic fields there is indeed no coupling whatsoever with the electrical properties of the crystal.”
“But if we increase the strength of the magnetic field, something remarkable happens: the holmium atoms change their quantum state and gain a magnetic moment. This breaks the internal symmetry of the crystal.”
From a purely geometrical point of view, the crystal is still symmetrical, but the magnetism of the atoms has to be taken into account as well, and this is what breaks the symmetry. Therefore the electrical polarization of the crystal can be changed with a magnetic field.
“Polarization is when the positive and negative charges in the crystal are displaced a little bit, with respect to each other,” Professor Pimenov said.
“This would be easy to achieve with an electric field — but due to the magnetoelectric effect, this is also possible using a magnetic field.”
The stronger the magnetic field, the stronger its effect on electrical polarization.
“The relationship between polarization and magnetic field strength is approximately linear, which is nothing unusual,” the physicist said.
“What is remarkable, however, is that the relationship between polarization and the direction of the magnetic field is strongly non-linear.”
“If you change the direction of the magnetic field a little bit, the polarization can completely tip over.”
“This is a new form of the magnetoelectric effect, which was not known before.”
So a small rotation may decide whether the magnetic field can change the electrical polarization of the crystal or not.
“The magnetoelectric effect will play an increasingly important role for various technological applications,” Professor Pimenov said.
“In a next step, we will try to change magnetic properties with an electric field instead of changing electrical properties with a magnetic field. In principle, this should be possible in exactly the same way.”
“If this succeeds, it would be a promising new way to store data in solids. In magnetic memories such as computer hard disks, magnetic fields are needed today.”
“They are generated with magnetic coils, which requires a relatively large amount of energy and time.”
“If there were a direct way to switch the magnetic properties of a solid-state memory with an electric field, this would be a breakthrough.”
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L. Weymann [i][i]et al[/i]. 2020. Unusual magnetoelectric effect in paramagnetic rare-earth langasite. [i]npj Quantum Mater[/i] 5, 61; doi: 10.1038/s41535-020-00263-9

[i]This article is based on text provided by the TU Wien.[/i]


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