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Saturday, 23 November 2019

A strange new world of light


Structured light

Over the past ten years, the physical developed nanostructured materials that can produce light beams completely out of the standard, which exhibit unusual behaviors such as spiral bending , corkscrew shape or that share as a Y .

These so-called structured light beams are not only revealing unknown things about the physics of light, they also have a wide range of practical applications, from super resolution images to microscopes and telescopes, to light-beam molecular manipulation and communications. by light without optical fibers.

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Now researchers have developed a tool that generates new, more complex light states in a completely different and configurable way.

"We have developed a metasurface that is a new tool for studying unpublished aspects of light. This optical component enables much more complex operations and allows researchers to not only explore new states of light but also new applications for structured light," said the professor. Federico Capasso, from Harvard University, USA.

Angular momentum and polarization

The metasurface connects two aspects of light: orbital angular momentum and circular polarization (or angular rotation pulse). In comparison to a planet, orbital momentum describes how the planet orbits the sun and circular polarization describes how the planet rotates about its own axis (rotation).

Light bias could already be used to control the size and shape of these exotic beams, but the connection was limited because only certain polarizations could be converted at certain orbital moments.

The new metamaterial significantly widens this connection. It can be designed so that any input bias can result in any orbital angular momentum output. In other words, any polarization can produce any kind of structured light, from spirals and corkscrews to vortices of any size.

Another great advantage is that the metasurface is multifunctional and can be programmed so that a polarization results in one vortex and a different polarization results in another completely different vortex.

Examples of structured light showing cross sections of beams.


Applications

Potential applications of this device include molecular manipulation and optical tweezers, which use light to move molecules and nanoparticles - the orbital momentum of light is strong enough to rotate and move microscopic particles.

Other fields of application include high resolution images, light beams for quantum computing, free space optical communication, and new light states in lasers.


Bibliography:

Article: Arbitrary spin-to-orbital angular momentum of light conversion

Authors: Robert C. Devlin, Antonio Ambrosio, Noah A. Rubin, JP Balthasar Mueller, Federico Capasso

Magazine: Science

Vol .: eaao5392

DOI: 10.1126 / science.aao5392


What can make artificial intelligence really intelligent?


Automated stupidity

Despite the many concerns about artificial intelligence and its growing role in society, the fact is that today's generation of artificial intelligence programs is not at all intelligent .

There are basically two types of machine learning: deep neural networks, those responsible for the famous "deep learning", and reinforcement learning networks. Both are based on system training, using huge amounts of data, to perform a specific task, for example making a decision.

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During training, the desired result is provided along with the task. Over time, the program learns to solve the task with ever faster accuracy, although no one understands exactly how the program works - it's the so-called "black box" of artificial intelligence .

"The problem with these machine learning processes is that they are basically completely dumb," says Professor Laurenz Wiskott of Ruhr University in Germany. "The underlying techniques date back to the 1980s. The only reason for today's success is that we have more computing power and more data at our disposal today."


But Professor Wiskott's team is trying to eliminate the stupidity of artificial intelligence and make it really smart.

Unsupervised artificial intelligence

Today artificial intelligence can be superior to humans specifically in the one task for which each program has been trained - it cannot generalize or transfer its knowledge even to similar tasks.

"What we want to know is, how can we avoid all this absurd and long training? And most of all: how can we make machine learning more flexible?" said Wiskott.

The strategy is to help machines autonomously discover structures in data. Tasks can include, for example, category formation or detection of gradual changes in videos. The idea is that this unsupervised learning allows computers to autonomously explore the world and perform tasks for which they have not been trained in detail.

"A task could be, for example, forming clusters," explains Wiskott. To do this, the computer is instructed to group similar data in search, for example, of a face in a photo. Turning the pixels into points in a three-dimensional space means grouping points whose coordinates are close to each other. If the distance between coordinates is greater, they will be allocated to different groups. This dispenses with the enormity of photos and their descriptions as used today.

This method offers more flexibility because this cluster formation is applicable not only to pictures of people, but also to cars, plants, houses or other objects.

Slow Principle

Another approach taken by the team is the slowness principle. In this case, it is not the photos that constitute the input signal, but moving images: If all the very slowly changing features are extracted from a video, structures appear that help construct an abstract representation of the environment. "Here, too, the goal is to pre-structure the input data," says Wiskott.

Eventually, researchers combine the two approaches in a modular way with supervised learning methods to create more flexible yet much more accurate applications.

"Greater flexibility naturally results in loss of performance," admits the researcher. "But in the long run, flexibility is indispensable if we want to develop robots that can handle new situations."

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First superconducting wind generator successfully tested

The superconducting generator is smaller and lighter than the equivalent of permanent magnets

Superconducting Wind Generator

A superconducting wind generator was successfully tested for the first time on an active, full-scale turbine.

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The 3.6 megawatt superconducting generator is designed, developed and manufactured by the European consortium EcoSwing, and field tested in Thyboron, Denmark.

"The size of wind turbines has increased significantly in recent decades. However, current technology has been having trouble keeping up with the trend of increasing levels of energy per unit," said Anne Bergen of the University of Twente in the Netherlands. Low.

To meet this challenge, the team built a “high temperature” (-196 ° C) barium oxide ( ReBCO ) superconducting wired generator , one of the rare earth family members.

This option required fewer rare earth materials than permanent magnet wind generators - also built with materials from the same family - resulting in a lower cost. The superconducting can also carry high current densities, resulting in denser in coil power and a smaller weight.

The union of universities and companies in the project allowed technology to be transferred from laboratories to industry

From lab to factory

"The generator field test was extremely successful. When the generator was installed at Thyboron, the turbine reached its desired power range, including over 650 hours of grid operation. This shows the compatibility of the superconducting generator technology with all elements of an operating environment such as variable speeds, grid failures, electromagnetic harmonics and vibrations, "said Bergen.

But the advances were not limited to the technical part of the generator.

"He demonstrated that the production of high temperature superconducting coils is not limited to specialized laboratories, but constitutes a successful technology transfer from science to industry. The high temperature superconducting rotor has also been assembled in an industrial environment, showing that Superconducting components can be deployed in a standard manufacturing environment.

"Now that the concept has been proven, we expect superconducting generator technology to begin to be widely applied to wind turbines ," added Bergen.


Bibliography:

Article: Design and in-field testing of the world's first ReBCO rotor for a 3.6 MW wind generator

Authors: Anne Bergen, Rasmus Andersen, Markus Bauer, Hermann Boy, Marcel ter Brake, Patrick Brutsaert, Carsten BΓΌhrer, Marc DhallΓ©, Jesper Hansen, Herman ten Kate, JΓΌrgen Kellers, Jens Krause, Erik Krooshoop, Christian Kruse, Hans Kylling, Martin Pilas, Hendrik PΓΌtz, Anders Rebsdorf, Michael Reckhard, Eric Seitz, Helmut Springer, Nir Tzabar, Sander Wessel, Jan Wiezoreck , Tiemo Winkler, Konstantin Yagotyntsev

Magazine: Superconductor Science and Technology

Vol .: 32, Number 12

DOI: 10.1088 / 1361-6668 / ab48d6

Friday, 22 November 2019

New experiments suggest the existence of a potential fifth fundamental force



According to the Standard Model, the Universe is governed by four elementary interactions: electromagnetism, weak and strong nuclear interactions, and gravity. For the first three, mediating particles, the bosons, have been identified. As for gravity, the existence of a graviton potential is still debated. But the Standard Model might not be complete. This is proposed by a team of Hungarian physicists whose recent experimental results suggest, according to their analysis, that there could be a fifth fundamental force. In 2016, the team had already highlighted some experimental evidence for a potential fifth elemental boson.

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The same team has now observed a second example of this potential fifth elemental force and the particle - called X17 - that carries it. If the discovery is confirmed, learning more about X17 could help us better understand the forces that govern our universe, but could also help physicists solve the problem of dark matter. However, these latest results have not yet been validated by peers, so they must be taken with extreme caution.


Attila Krasznahorkay and colleagues at the Hungarian Nuclear Research Institute suspected something strange in 2016 after analyzing how an excited beryllium-8 atom emits light when it disintegrates. If this light is energetic enough, it is transformed into an electron and a positron, which move away from each other at a predictable angle.

A statistical anomaly in the particle separation angle

On the basis of the law of conservation of energy, as the energy of the light producing the two particles increases, the angle between them should decrease. Statistically speaking, at least. But, that's not quite what Krasznahorkay and his team saw. Among the different angles observed, there was an unexpected increase in the number of electrons and positrons separating at an angle of 140 degrees.

In their experiment on beryllium-8, the researchers found an abnormal number of particle pairs separating at an angle of 140 ° (angular correlation). Credits: AJ Krasznahorkay et al. 2019

The study seemed serious enough and quickly attracted the attention of other researchers around the world, who suggested that a whole new particle could be responsible for the anomaly. And its characteristics suggested that it must be a completely new type of fundamental boson.

This new boson can not be one of the fundamental bosons already known, considering its distinctive mass of 17 megaelectronvolts (MeV) - about 33 times that of an electron, and its very short life (10-14 seconds ).

All these data therefore seem to indicate the existence of a fifth force. However, the discovery of a new particle, and a fortiori a new boson, requires several careful examinations and experimental repeatability before being announced.

New experimental evidence for a potential fifth fundamental force

To do this, the Krasznahorkay team decided to hunt down this potential new boson in another experiment, moving from the decay of beryllium-8 to a change in the state of an excited helium nucleus.

Similar to their previous discovery, the researchers found pairs of electrons and positrons separating at an angle that does not fit the currently accepted models. This time the number was closer to 115 degrees.

In their new experiment involving an excited helium nucleus, the researchers again observed an abnormal angular correlation for the electron-positron pairs, but this time around 115 °. Credits: AJ Krasznahorkay et al. 2019

The team calculated that the helium nucleus could also have produced an ephemeral boson with a mass of just under 17 megaelectronvolts. While the 2016 experience has been accepted in the very serious journal Physical Review Letters , this latest study has not yet been peer-reviewed. It is however freely available on the pre-publication server arXiv .

Many other experiments, including those conducted by independent teams, will have to be conducted, and the initial results will have to be corroborated before any official announcement can be made.

The results obtained by the Krasznahorkay team are still far from sufficient. However, if the discovery of a fifth boson was to be confirmed, it could announce a revolution in the field of dark matter. A number of experiments on dark matter actually looking for a 17 MeV peak.

Source

For the first time, humans have been placed in biostasis


Biostasis, or "suspended animation," is a hibernation-like technique that researchers and doctors believe could help save many lives in the future. Indeed, at present, there are already short or partial techniques that have an almost automatic and natural reversibility.

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And now, scientists have been able to take a step further in this area: doctors have placed humans in biostasis for the first time, in a trial conducted in the United States and intended to allow the repair of traumatic lesions that otherwise would cause death.

Samuel Tisherman, of the University of Maryland's Faculty of Medicine, said his team of doctors had placed at least one suspended animation patient, calling this world premiere a "somewhat surreal" event. That is, Tisherman has not yet revealed the number of people who survived following the test.


The main goal is to prevent an impending death by ischemia

The technique used by the Tisherman team is officially called Emergency Preservation and Resuscitation (EPR). This is a medical procedure in which a patient is placed on biostasis for a period of time to prevent imminent death caused by ischemia, such as blood loss from a bullet or stab.

This technique is being tested on patients at the University of Maryland Medical Center in Baltimore. More specifically, in patients with acute trauma (as mentioned above, who, for example, have a gunshot or knife wound) and have suffered cardiac arrest.

Following the trauma, their heart will have stopped beating and they may have lost more than half of their total amount of blood. In this situation, there are only a few minutes of life for patients, with less than 5% chance of survival, at least in normal times ...


Biostasis: rapid cooling of the body by replacing blood

Biostasis involves rapidly cooling a person to about 10 to 15 ° C by replacing all his blood with a very cold saline solution. In doing so, the brain activity of the patient stops almost completely. He is then disconnected from the cooling system and the body (which would otherwise be classified as dead) is transferred to the operating room. From this point on, the surgical team has approximately 2 hours to repair the person's wounds before the person warms up again, and his / her heart starts up again.

Now, Tisherman hopes to be able to announce the full results of the test by the end of 2020.

It should be known that a so-called normal body temperature is about 37 ° C, and our cells need a constant supply of oxygen to produce energy and therefore survive. When our heart stops beating, the blood no longer transports oxygen to the cells, and without it our brain can only survive for about 5 minutes before irreversible damage occurs.

However, lowering body and brain temperature slows down or stops all chemical reactions in our cells, which therefore require less oxygen.

The test has been approved by the FDA (US Food and Drug Administration). In fact, the FDA has decided not to require patients' consent, as they believe the injuries of the patients may be fatal and that in any case there will be no alternative treatment.


Gives surgeons more time to save more lives

Tisherman's interest in trauma research began with an early incident in his career in which a young man was stabbed to the heart after an altercation.

"He was a healthy young man a few minutes ago, and suddenly he was dead. We could have saved him if we had enough time, "he says. This event led him to begin to look for ways in which cooling the body could give surgeons more time to do their jobs, and save lives.

Studies in animals have already shown very promising results: for example, pigs with acute trauma could be cooled for 3 hours, then treated, and then resuscitated.

" We felt it was time to apply this technology to our patients, " said Tisherman. " We are doing it now and we are learning a lot as we go through the trial. Once we have proven that it works (on human patients), we can expand the utility of this technique to help some patients in critical conditions to survive, which would otherwise be  impossible, "he added. "  I want to make it clear that we are not trying to send people to Saturn.  We are just trying to save time to save lives, "he said.

At present, we do not know exactly how much time we have precisely when such a cooling of the body. And when a person's cells are warmed up later, they can be damaged and can cause a range of chemical reactions, potentially damaging them again. To sum up, the longer the cells stay without oxygen, the greater the damage will be.

According to Tisherman, it would be entirely possible to administer a cocktail of drugs to patients in order to minimize injuries and prolong the duration of the biostasis, "but we have not yet identified all the causes of the injuries due to reperfusion, "he says. It was last Monday, at a symposium at the New York Academy of Sciences, that Tisherman described the progress of the team.

VIDEO: A revolutionary approach that could save many lives ...


Source

Thursday, 21 November 2019

Discovery reveals mechanism that activates and deactivates herpes virus


Researchers at the Baker Institute for Animal Health have discovered a mechanism that plays an important role in controlling the alternation of the herpes virus. He would be involved in the switch between dormant and active stage of the virus.

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The herpes virus is formidable and especially very embarrassing for people with the disease. It can cause "cold sores" and genital lesions, as well as life-threatening infections in newborns, encephalitis and corneal blindness. The treatment of the virus is difficult because it hides in the nerve cells and emerges months or years later to reactivate the infection.


Led by Dr. Luis M. Schang, Mi Yao Hu and Esteban Flores Cortes, a research team at the Baker Institute for Animal Health in New York, discovered that the virus is changing from "latent" to "lytic" ( in which it replicates actively) depending on the narrowness of the structure within which the DNA is packaged, chromatin. The results of the study were published on November 14 in the journal PLOS Pathogens .

Schang's group collaborated with scientists at the University of Alberta, Canada, and University College London (UCL).

" Any problem that herpes causes is due to the reactivation of latency,  " said Schang. " That's why antivirals can not cure the infection and why so far it has not been possible to develop a vaccine. Latency and reactivation are major axes of research on the herpes virus.

Histones, proteins around which DNA wraps

When the herpes virus enters a cell, it attempts to protect itself by tightly wrapping the viral DNA around the histones (coil-shaped proteins) and condensing it into the chromatin, resulting in dormancy. of the virus. But if the cells fail in this process, the chromatin is only weakly bound, leaving the viral DNA accessible. The virus particles can then activate their genes and replicate using the cellular machinery to trigger a lytic infection, causing the disease.

Most researchers focused on the timing and process of activation and deactivation of individual genomes of the herpes virus genome during infection, to determine how the virus switches between latent and lytic stages.

Diagram (from another study ) explaining how stress stimulates the reactivation of HSV at the "latent" stage. A pathway of neuronal stress involving the activation of the c-Jun N-terminal kinases (JNK) is crucial for the reactivation of the virus. JNK signaling induces histone phosphorylation of viral promoters, thus linking cell stress to viral gene expression. Credits: Cliffe et al.

A hitherto neglected way of regulating the expression of the genes of the virus

In the new study, however, the group showed that chromatin dynamics regulates genome activation of the herpes virus as a whole, which must occur before each gene can be expressed. This new mechanism represents a hitherto neglected way of regulating the expression of genes at the level of the whole of the viral chromosome.

With this new knowledge , researchers can further explore the interaction between virus and host cells determining whether viral DNA is expressed or not. Antiviral drugs to treat herpes have been around since the 1960s, but so far no cure or effective vaccine has been possible.

" Latency and gene regulation is a major problem because we do not know enough about it, " said Schang. " It's a big black box in herpes biology  ."

The discovery opens new perspectives to explore the reactivation of the virus after a period of latency. The ability of herpes to hide has hitherto thwarted efforts to develop effective vaccines or antiviral drugs to prevent or completely cure the infection.


Bibliography:

Article: Chromatin dynamics and the transcriptional competence of HSV-1 genomes during lytic infections


Authors: MiYao Hu, Daniel P. Depledge, Esteban Flores Cortes, Judith Breuer, Luis M. Schang

PLoS Pathog 15(11): e1008076.
doi:10.1371/journal.ppat.1008076

First detection of sugars necessary for life found in meteorites



The origin of life on Earth is an open question and represents a field of active research. Although prebiotic models of the appearance of life have been proposed, the process of appearance of building blocks of life (amino acids, nucleic acids, sugars, etc.) is still very little constrained. One of the hypotheses currently proposed proposes an extraterrestrial origin of these components within the framework of a model called panspermia. In this model, the constituents of life would have been brought to the primitive Earth through the incessant bombardment of comets and meteorites. And recently, researchers have for the first time discovered ribose and other sugars necessary for life in two meteorites, thus reinforcing this hypothesis.

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An international team of researchers has found sugar molecules essential for life in meteorites. This new discovery adds to the growing list of biologically important compounds found in meteorites, furthering the hypothesis that chemical reactions in asteroids - the parent bodies of many meteorites - can make certain life ingredients. If this is correct, the bombardment of meteorites on the primitive Earth may have helped the appearance of life by providing the basic elements.


First direct evidence of the existence of extraterrestrial ribose

The team discovered ribose and other bio-essential sugars, including arabinose and xylose, in two carbon-rich meteorites, NWA 801 (CR2 type) and Murchison (CM2 type).

Ribose is a crucial component of RNA (ribonucleic acid). RNA serves as a messenger molecule, copying the genetic instructions of the DNA molecule (deoxyribonucleic acid) and transmitting them to molecular factories within the cell, called ribosomes, which read RNA to construct specific proteins.

Structures of sugars (pentoses) discovered in the two meteorites. Credits: Yoshihiro Furukawa et al. 2019

" Other important elements in life have already been discovered in meteorites, including amino acids (protein components) and nucleic bases (components of DNA and RNA), but sugars have been an element missing among the main building blocks of life, "said Yoshihiro Furukawa of Tohoku University, Japan. " The research provides the first direct evidence of ribose in space and the contribution of sugar to Earth. The extraterrestrial sugar could have contributed to the formation of RNA on the prebiotic Earth, which probably led to the origin of life .

" It's remarkable that a molecule as fragile as ribose can be detected in such an old material, " says Jason Dworkin, an astrobiologist at NASA's Goddard Center. " These results will help guide our sample analyzes of the original Ryugu and Bennu asteroids, which will be returned by Hayabusa 2 of the Japan Aerospace Exploration Agency and NASA's OSIRIS-REx space probe ."


Ribose: a sugar used in the composition of RNA

A persistent mystery about the origin of life is how biology could have come from non-biological chemical processes. DNA contains the genetic instructions necessary for the functioning of a living organism. However, RNA also contains information and many researchers believe that it evolved first and was later replaced by DNA. This is because RNA molecules have abilities that are lacking in DNA.

Structure of the RNA. RNA uses ribose as sugar, unlike DNA that uses deoxyribose. Credits: BioC

RNA can reproduce without the need for other molecules, and it can also initiate or accelerate chemical reactions as a catalyst. These results support the possibility that RNA has coordinated the mechanism of life before DNA.

" The sugar contained in DNA (2-deoxyribose) was not detected in any of the meteorites analyzed in this study. This is important because there may be a lack of extraterrestrial ribose delivery to the early Earth, which is consistent with the hypothesis that RNA evolved first, "explains Danny Glavin.

Sugars brought by meteorites from space

The team discovered sugars by analyzing powdered meteorite samples using gas chromatography mass spectrometry, which sorts and identifies molecules based on their mass and electrical charge. They found that the abundances of ribose and other sugars ranged from 2.3 to 11 parts per billion in NWA 801, and from 6.7 to 180 parts per billion in the Murchison meteorite.

With the Earth now full of life, the team had to take into account the possibility that meteorite sugars could have simply come from a terrestrial contamination. Several sources of data indicate that contamination is unlikely, including isotopic analysis. Isotopes are versions of a different mass element because of the number of neutrons in the nucleus of the atom.

The isotopic analysis of the sugars found in the meteorites confirmed that they came from space, not from the Earth. Credits: Yoshihiro Furukawa et al. 2019

Carbon chemistry on Earth uses carbon 12 compared to the heavier version (carbon 13). However, the carbon contained in meteorite sugars was significantly enriched in carbon 13, beyond the amount observed in terrestrial biology, which corroborates the conclusion that it comes from space.

Towards a better understanding of the emergence of life on Earth

The team plans to analyze more meteorites to get a better idea of ​​the abundance of extraterrestrial sugars. They also plan to determine whether extraterrestrial sugar molecules have a preferred left or right orientation. Some molecules come in two varieties that are inverted images of each other. On Earth, life uses left amino acids and straight sugars.

Since it is possible that the opposite works perfectly - right amino acids and left sugars - scientists want to know where this preference comes from. If some processes in asteroids favor the production of one variety over another, then perhaps the influx from space via meteorite impacts has made this variety more abundant on the ancient Earth.

Bibliography:

 Extraterrestrial ribose and other sugars in primitive meteorites

 Yoshihiro Furukawa, Yoshito Chikaraishi, Naohiko Ohkouchi,  View ORCID ProfileNanako O. Ogawa, Daniel P. Glavin,  View ORCID ProfileJason P. Dworkin, Chiaki Abe, and Tomoki Nakamur

PNAS first published November 18, 2019

https://doi.org/10.1073/pnas.1907169116


Wednesday, 20 November 2019

Unique glow never seen before discovered, thanks to the MeerKAT radio telescope


There is talk of a "unique and never seen before glow" in the press release published on the University of Manchester website which presents the discovery made by a group of scientists who used the MeerKAT radio telescope in South Africa to discover a source of radio emissions that it quickly lit up to a level out of the ordinary for a period of three weeks.

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This is a "transient" astronomical event, events in which the emitting source appears and then disappears or becomes brighter and then weaker again in periods of time that can be calculated in seconds, days or even years.


In this case the researchers found that the source comes from a binary system of two objects that orbit each other every 22 days. What are the components of this binary system is still uncertain as is the cause of the anomalous glow they have identified.

What is known is that the source is located near a K type subgiant star, with a mass twice that of the Sun, previously identified in the constellation of the Altar.

"Once we discovered that the glow of the radio source coincided with a star, we discovered that the star emits through almost the entire electromagnetic spectrum from X-rays to the wavelengths of UV and radio rays," explains Laura Driessen, researcher of the University of Manchester who led the team that made the discovery and then published their work in Monthly Monthly of the Royal Astronomical Society .

According to Ben Stappers, a researcher from the same university that participated in the study, we may be faced with a new class of radio wave emitter objects that is completely new as its properties do not coincide with those of the models we are currently aware of.




Bibliography:

MKT J170456.2−482100: the first transient discovered by MeerKAT


L N Driessen, I McDonald, D A H Buckley, M Caleb, E J Kotze, S B Potter, K M Rajwade, A Rowlinson, B W Stappers, E Tremou, P A Woudt, R P Fender, R Armstrong, P Groot, I Heywood, A Horesh, A J van der Horst, E Koerding, V A McBride, J C A Miller-Jones, K P Mooley, R A M J Wijers

Monthly Notices of the Royal Astronomical Society, stz3027,

https://doi.org/10.1093/mnras/stz3027



More than 140 new Nazca geoglyphs have been discovered


In 1927, archaeologists discovered for the first time from the air stylized representations of humans, animals and objects of various sizes (between a few tens of meters and several kilometers) drawn in the soil of the Nazca desert in southern Peru. Called the Nazca Geoglyphs, the purpose in which they were traced by the Nazca civilization is still unknown. Recently, a team of archaeologists discovered 143 new geoglyphs, including one thanks to artificial intelligence . This discovery could help to better understand the functions of these representations.

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Scientists have discovered more than 140 new geoglyphs, known as Nazca Geoglyphs (or Nazca Lines): an ancient and mysterious group of giant characters engraved in the desert of southern Peru. These massive and sprawling representations of human beings, animals and objects can be as old as 2500 years old and so impressive that many of them can only be identified from the air.

Archaeologists at the Japanese University of Yamagata report that a long-term study conducted since 2004 has uncovered 143 previously unknown Nazca geoglyphs, including a figure who escaped human detection and discovered by artificial intelligence.

Humanoid geoglyph (about 10 meters long). Credits: Yamagata University

Geoglyphs with still unexplained objectives

The newly identified geoglyphs would have been created between at least 100 BCE and 300 EC. Although the purpose of these great motifs inspired by the ancient culture of Nazca remains controversial, the way they were made is known to archaeologists. " All these figures were created by removing the black stones that cover the earth, exposing the white sand underneath, " says the research team.

Geoglyph representing a bird (about 100 meters long). Credits: Yamagata University

Previous assumptions have suggested that the Nazca people have shaped the giant geoglyphs - some of which are hundreds of meters long - to be seen by deities in the sky or to serve astronomical purposes.

In the new research, led by anthropologist and archaeologist Masato Sakai, the team analyzed the high-resolution satellite imagery of the Nazca region, also conducted fieldwork and identified two main types of geoglyphs.

Two types of geoglyphs with potentially distinct functions

The oldest geoglyphs (100 AECs), called type B, are generally less than 50 meters, while the slightly more recent ones (100 and 300 EC), called type A, extend over 50 meters, with the largest geoglyph discovered by the team measuring more than 100 meters.

Researchers believe that type A geoglyphs, larger, often shaped like animals, were ritual places where people organized ceremonies involving the destruction of various pottery vases.

Geoglyph representing a two-headed serpent (about 30 meters long). Credits: Yamagata University

On the other hand, the smaller Type B patterns were located along trails and could have served as a relay to guide travelers - possibly to a larger Type A ritual space where people would gather. Some of these Type B designs are really tiny, the smallest of new discoveries measuring less than 5 meters, making it difficult to find this type of line.

The help of artificial intelligence in the discovery of geoglyphs

To this end, as part of a recent experimental collaboration that began in 2018 with IBM researchers, the team used a company-developed Deep Learning artificial intelligence that runs on a geospatial analysis system. called IBM PAIRS geoscope.

Humanoid geoglyph discovered by IBM's artificial intelligence (about 4 meters long). Credits: Yamagata University

The Learning Network - IBM Watson Machine Learning Accelerator (WMLA) - has screened huge volumes of images of drones and satellites to see if it can spot hidden marks related to the Nazca lines.

The system found a match: the faded outline of a small humanoid type B, resting on two feet. Although the symbolic meaning of this strange and ancient character is not yet clear, the researchers point out that the geoglyph was located near a path, which makes it perhaps one of the supposed beacons.

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Tuesday, 19 November 2019

NASA confirms the presence of water vapor on the surface of Europa


The fourth largest natural satellite of Jupiter and sixth largest in the Solar System, Europa has been of interest to planetologists for many years. About forty years ago, the Voyager program provided the first detailed picture of the veined surface of the icy moon. In the last decades, the data collected on Europa has made it a priority target for space agencies in the search for life. And recently, planetologists have confirmed the presence of water vapor in Europe.

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What makes this moon so attractive is the possibility that it has all the ingredients necessary for life. Planetologists have evidence that one of these ingredients, liquid water, is present under the icy surface and can sometimes burst into space in the form of gigantic geysers. But so far no one has been able to confirm the presence of water in these plumes by directly detecting the water molecule.

Europa: water vapor and a potential ocean of liquid water

Now, an international research team led by NASA's Goddard Space Flight Center has directly detected water vapor for the first time over the surface of Europa. The team did this detection by surveying Europa through one of the largest telescopes in the world in Hawaii.

By confirming the presence of water vapor over Europa, planetologists can better understand the inner workings of the moon. For example, it helps to support the idea that there is an ocean of liquid water, perhaps twice as large as the Earth's, beneath the thick ice shell of that moon. Some astrophysicists suspect that another source of water for the plumes could be shallow reservoirs of melted water ice.

Although planetologists have still not surveyed the interior of Europe, the predominant hypothesis suggests the existence of an ocean of liquid water beneath its frozen surface. Credits: NASA

" The essential chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur) and energy sources, two of the three requirements of life, are present throughout the Solar System. But the third - liquid water - is a little hard to find beyond the Earth, "said Lucas Paganini, NASA's planetologist. " Although the scientists have not yet detected the liquid water directly, we have found the second best thing: water in the form of steam ."

First direct detection of water molecules over Europa

In Nature Astronomy , Paganini and his team said they detected enough water ejected from Europa (at a rate of 2360 kilograms per second) to fill an Olympic pool in minutes. However, the authors also discovered that water appears too rarely, at least in sufficient quantity, to be detected from Earth.

" For me, the interest of this work is not only the first direct detection of water over Europa, but also its absence within the limits of our detection method, " says Paganini.

Indeed, Paganini's team detected the weak but distinct signal of water vapor during 17 nights of observation between 2016 and 2017. Looking at the moon from WM Keck observatory at the top of Mauna Kea volcano in Hawaii, researchers have seen water molecules on the main hemisphere of Europa. (Europa, like the Earth's moon, is gravitationally locked on its host planet, so the main hemisphere is always oriented in the direction of the orbit, while the secondary hemisphere is always in the opposite direction).

Differentiate terrestrial water vapor from that of Europa: models in reinforcement

For this, the researchers used a Keck observatory spectrometer, which measures the chemical composition of planetary atmospheres by means of the infrared light they emit or absorb. Molecules such as water emit specific frequencies of infrared light when they interact with solar radiation.

When interacting with solar radiation, water molecules emit specific infrared frequencies. Credits: Michael Lentz / NASA Goddard

Detecting water vapor on other worlds is a challenge. Existing spacecraft have limited capabilities to detect it, and scientists using ground-based telescopes must take into account the distortion effects of the Earth's atmosphere.

To minimize this effect, Paganini's team used complex mathematical and computer modeling to simulate the conditions of the Earth's atmosphere, in order to differentiate between atmospheric water from Earth and Europa from the atmosphere. data returned by the Keck spectrograph.

We conducted rigorous safety checks to eliminate potential contaminants in ground observations, " said Avi Mandell, a planetologist on the Paganini team. " But in the end, we will have to get closer to Europa to see what is really happening ."

Structure of Europa: study it in detail thanks to the Europa Clipper mission

Scientists will soon be able to get close enough to Europa to resolve their outstanding questions about the internal and external functioning of this possibly habitable world. The next mission, Europa Clipper, which is scheduled for launch in the mid-2020s, will complete half a century of scientific discoveries that began with a modest photo.

When it arrives in Europa, the Clipper orbiter will carry out a detailed study of the surface, the deep interior, the weak atmosphere, the submarine ocean and possibly even smaller active vents. Clipper will try to take images of all the plumes and sample the molecules he will find in the atmosphere to study with his mass spectrometers. He will also look for a site from which a future lander could collect a sample.

In this video, NASA returns in detail on the detection of water vapor in Europa:



Bibliography:

Article: A measurement of water vapour amid a largely quiescent environment on Europa

authors: L. Paganini, G. L. Villanueva, L. Roth, A. M. Mandell, T. A. Hurford, K. D. Retherford & M. J. Mumma

Nature Astronomy

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New material breaks all records for thermoelectric power generation


More and more technologies are using thermoelectricity to supply energy. Thermoelectric energy comes from the conversion of heat into electricity through temperature differences. However, the usual thermoelectric materials generate a relatively small amount of energy. But recently, Austrian physicists have developed a brand new thermoelectric material breaking all records of the amount of energy generated. Such a material could equip the sensors and processors to self-power.

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Thermoelectric materials can convert heat into electrical energy. This is due to the Seebeck effect: if there is a temperature difference between the two ends of such a material, an electrical voltage can be generated and the current can begin to flow. The amount of electrical energy that can be generated at a given temperature difference is measured by the so-called ZT value: the higher the ZT value of a material, the better its thermoelectric properties.

The best thermoelectric materials to date have been measured at ZT values ​​of about 2.5 to 2.8. The physicists of the Technical University of Vienna have succeeded in developing a brand new material with a ZT value of 5 to 6. It is a thin layer of iron, vanadium, tungsten and aluminum applied on a silicon crystal.

The new material is so efficient that it could be used to provide power to sensors or even small computer processors. Instead of connecting small electrical devices to cables, they could generate their own electricity from temperature differences. The study was published in the journal Nature .

A combination of iron, vanadium, tungsten and aluminum

" A good thermoelectric material must have a strong Seebeck effect and must meet two important requirements, which are difficult to reconcile, " says physicist Ernst Bauer of the Institute of Solid Physics at TU Wien. " On the one hand, he must conduct electricity as well as possible; on the other hand, it must conduct the heat as little as possible. This is a challenge because electrical conductivity and thermal conductivity are usually closely related .

At the Christian Doppler laboratory for thermoelectricity, created by Ernst Bauer at TU Wien in 2013, various thermoelectric materials for different applications have been studied in recent years. This research has now revealed a particularly remarkable material: a combination of iron, vanadium, tungsten and aluminum.

Atomic structure of the new material. Credits: B. Hinterleitner et al. 2019

The atoms of this material are generally arranged in a strictly regular manner in a face-centered cubic lattice. The distance between two iron atoms is always the same, and the same goes for the other types of atoms. The whole crystal is therefore perfectly regular, "explains Bauer.

Weyl fermions and low thermal conductivity in crystalline structure

However, when a thin layer of material is applied to silicon, something amazing happens: the structure changes dramatically. Although atoms always form a cubic pattern, they are now arranged in a space-centered structure, and the distribution of different types of atoms becomes completely random.

" Two iron atoms can be assembled next to each other, adjacent sites can be filled with vanadium or aluminum, and there is no longer a rule dictating the location of the next iron atom in the crystal ".

This mixture of regularity and irregularity of the atomic arrangement also modifies the electronic structure, which determines the way in which the electrons move in the solid. " The electric charge moves in a particular way in the material in order to protect it from diffusion processes .  The charges passing through the material are called Weyl Fermions . In this way, a very low electrical resistance is obtained.

Graphics showing the thermoelectric properties of the material. Credits: B. Hinterleitner et al. 2019

On the other hand, the vibrations of the network, which carry the heat from the high temperature zones to the low temperature zones, are inhibited by the irregularities of the crystalline structure. As a result, the thermal conductivity decreases. This is important if the electrical energy has to be generated permanently from a temperature difference - because if the temperature differences could be balanced very quickly and all the material had the same temperature everywhere, the thermoelectric effect 'stop.

Equip interconnected technologies with standalone power

Of course, such a thin layer can not generate a particularly large amount of energy, but it has the advantage of being extremely compact and adaptable. We want to use it to provide energy for sensors and small electronic applications . "

The demand for such small-scale generators is growing rapidly: in the "Internet of Things", more and more devices are connected together online, so they automatically coordinate their behavior with each other. This is particularly promising for future production plants, where one machine must react dynamically to another.

" If you need a lot of sensors in a plant, you can not connect them together. It's much smarter for the sensors to be able to generate their own power using a small thermoelectric device, "concludes Bauer.

Bibliography:

Article: Thermoelectric performance of a metastable thin-film Heusler alloy

Authors: B. Hinterleitner, I. Knapp, E. Bauer

Nature (2019)

Source


Monday, 18 November 2019

New device allows dressing to be applied directly to wounds



Placing bandages or bandages directly on a wound may be difficult in some medical emergencies. The staff must handle the bandages carefully to preserve both sterility and integrity. To get around this problem, a team of bioengineers has developed a portable electrospinning device that, like a spray of paint, can spray a medical dressing directly onto a wound.

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With this new technology, medical personnel can fabricate a dressing with drug delivery capabilities directly to a wound. Electrospinning is a method of developing polymer fibers for a wide variety of applications. If biocompatible materials are used, the fibers produced can be used for biomedical applications.


However, electrospinning requires very high voltages, which makes it dangerous to deposit fiber directly on biological material because of the risk of electrocution it creates.

A group of researchers at Montana Technological University has developed a portable electrospinning device with a confined electric field that can safely deposit bandages and drugs directly onto biological surfaces. The team described the instrument in the journal Journal of Vacuum Science & Technology B .

Spray dressings on the wound like a paint spray

Instead of using the difference in tension between the tool and a surface to deposit the fibers, the new device uses air to spray the fibers on the surface, in the manner of a spray paint. " In spray painting, the pressurized gas forces the particles to go to a surface, creating a kind of deposited material, " said Lane Huston, engineer at Montana Tech.

Demonstration of the dressing projection on a gloved hand, 1 min after projection (A) and 3 min after (B). Credits: Lane G. Huston et al. 2019

As with spray painting, the EStAD device is used by directing its nozzle on the desired surface during operation, which causes the deposition of a mat of fibers on this surface ."

By applying this mechanism similar to aerosol paint, the device can be used to cover wounds and allow controlled release of the drug over time. The deposited fibers adhere to materials containing internal moisture, such as human skin.

The researchers tested the dressing projection on pork skin (top) and on fruits (bottom). Fibers adhere to many types of surfaces. Credits: Lane G. Huston et al. 2019

Although the use of electrospun fibers for effective drug delivery has been established in the past, the foregoing methods required that a wound be placed directly in the path of the electric field. In this configuration, the only safe option is to pre-deposit fibers on a surface, such as parchment paper, to collect them and store them for later use.

Assist medical staff in areas inaccessible to emergency care

The device was tested on a pork skin incision as well as on a gloved human hand. This is the first demonstration of safely depositing fibers delivering the drug directly to the wound site.

The authors hope that this new technology will be used to help doctors, first responders and medical staff treat wounds in rural areas, where immediate medical care may not be readily available.

" The bandage, as well as the drug used, can be chosen on demand if the situation warrants it, thus allowing for modular and adaptable treatment of the accessible drug in isolated areas " Huston. Although the direct deposit method is its preferred application, the researchers' new device can also be used as a traditional table electrospinning device.



Bibliography:

 Article: Combined electrostatic and air driven electrospinning for biomedical applications featured

Journal of Vacuum Science & Technology B 37, 062002 (2019);

https://doi.org/10.1116/1.5122659

Lane G. Hustona), Emily A. Kooistra-Manning,  Jack L. Skinner, and Jessica M. Andriolo

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New technology makes it possible to project 3D tactile and sound images


The dream of science fiction writers, holograms are now an active field of research, and more and more advanced prototypes have emerged in recent years. If the technology is not yet to match the holographic projectors of the Star Wars franchise, engineers are continually surpassing new limits. This is the case of a recently developed pseudo-holographic technology, based on an ultrasound system, for projecting shapes and touching them.

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Researchers in Sussex have developed a device that projects animated objects in 3D that can interact with viewers. A demonstration showed a butterfly flapping its wings, a countdown detailed by numbers hanging in the air and a planet Earth in rotation and multicolored. Beyond digital signs and interactive animations, scientists want to use it to visualize and better perceive data.

Although the images are similar, the camera is not the kind of holographic projector for Star Wars movies. Instead, he uses a 3D field of ultrasonic waves to levitate a polystyrene bead and model it at high speed to draw shapes in the air. The study was published in the journal Nature .


3D images created with a pearl and ultrasound

The 2 mm wide bead moves so fast, at speeds approaching 20 km / h, that it traces the shape of an object in less than a tenth of a second. At such a speed, the brain does not see the pearl in motion, only the complete form it creates. The colors are added by integrated LEDs on the screen, which illuminate the pearl as it moves.

Diagram describing the projection device used, as well as some forms created by the device. Credits: Ryuji Hirayama et al. 2019

Because images are created in a 3D space, they can be viewed from any angle. And by carefully controlling the ultrasonic field, scientists can make objects talk or add sound effects and musical accompaniments to moving images. Further manipulation of the sound field allows users to interact with objects and even feel them in their hands.

A step towards next-generation visual entertainment

Sriram Subramanian, team director, explains that besides digital signage, the display could also be used for new forms of visual entertainment. " Let's say you want to create a Harry Potter experience. You can reach out to cast a spell and, as you move it, you can see and feel a glowing ball grow in your palm, and we could also have a sound coming out of it . "

Ryuji Hirayama, who participated in the construction of the screen, says that making such a device was a long-time dream. But he considers that "the display of multimodal acoustic traps" is a step towards more sophisticated systems. " I think that in the future, such screens will allow us to interact with our family and friends as if they were nearby, so we can see them, touch them and hear them ."

Sound and tactile images

The images are created between two horizontal plates dotted with small ultrasonic transducers. These create an inaudible 3D sound field containing a tiny pocket of low pressure air that traps the polystyrene bead.

Move the pouch slightly changing the output of the transducers and the pearl moves with it. The most basic version of the display creates 3D color animations, but the authors describe how they improved the display to produce sounds and tactile responses.

Technology can create a variety of colorful 3D shapes, accompanied by sounds and a tactile response. Credits: Ryuji Hirayama et al. 2019

Speech and other sounds, such as musical accompaniment, were added by vibrating the polystyrene bead when it was around it. Vibrations can be tuned to produce sound waves across the entire range of human hearing, creating, for example, clear, clear speech. Another trick is making touch display by manipulating the ultrasound field to create a virtual "button" in suspension.


Towards advanced holographic technology for everyone

The prototype uses a single bead and can create images in an air cube 10 cm wide. But future displays could use more powerful transducers to create larger animations and use multiple beads at once.

Subramanian stated that existing computer software could be used to prevent small pearls from colliding with each other, although the choreography of lighting several beads in the air is another problem. If technology can be improved, it could transform 3D printing by building objects from tiny droplets of different levitating materials.

" What's interesting about the tactile content is that it was created using ultrasonic waves. Unlike the simple vibrations that most people experience via smartphones or game consoles, ultrasound moves through the air to create precise patterns against the hands. This allows for multimedia experiences where the objects you feel are as rich and vibrant as the ones you see on the screen, "says Euan Freeman of the University of Glasgow.


Julie Williamson, also from Glasgow, says that levitating screens are a first step towards truly interactive 3D displays. " I imagine a future where 3D displays can create experiences that are indistinguishable from the physical objects they simulate ."

This video summarizes the work of researchers and shows technology in action:



Bibliography:

Article: A volumetric display for visual, tactile and audio presentation using acoustic trapping

Authors: Ryuji Hirayama, Diego Martinez Plasencia ', Nobuyuki Masuda' & Sriram Subramanian

DOI:  https://doi.org/1o1038/s41586-019-1739-5

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