Date:
May 19, 2020

Source:
University of Surrey

Summary:
Scientists have taken inspiration from the biomimicry of
butterfly wings and peacock feathers to develop an innovative
opal-like material that could be the cornerstone of next
generation smart sensors.

FULL STORY
__________________________________________________________________

Scientists have taken inspiration from the biomimicry of butterfly
wings and peacock feathers to develop an innovative opal-like material
that could be the cornerstone of next generation smart sensors.

An international team of scientists, led by the Universities of Surrey
and Sussex, has developed colour-changing, flexible photonic crystals
that could be used to develop sensors that warn when an earthquake
might strike next.

The wearable, robust and low-cost sensors can respond sensitively to
light, temperature, strain or other physical and chemical stimuli
making them an extremely promising option for cost-effective smart
visual sensing applications in a range of sectors including healthcare
and food safety.

In a study published by the journal Advanced Functional Materials,
researchers outline a method to produce photonic crystals containing a
minuscule amount of graphene resulting in a wide range of desirable
qualities with outputs directly observable by the naked eye.

Intensely green under natural light, the extremely versatile sensors
change colour to blue when stretched or turn transparent after being
heated.

Dr. Izabela Jurewicz, Lecturer in Soft Matter Physics at the University
of Surrey's Faculty of Engineering and Physical Sciences, said "This
work provides the first experimental demonstration of mechanically
robust yet soft, free-standing and flexible, polymer-based opals
containing solution-exfoliated pristine graphene. While these crystals
are beautiful to look at, we're also very excited about the huge impact
they could make to people's lives."

Alan Dalton, Professor Of Experimental Physics at the University of
Sussex's School of Mathematical and Physical Sciences, said: ""Our
research here has taken inspiration from the amazing biomimicry
abilities in butterfly wings, peacock feathers and beetle shells where
the colour comes from structure and not from pigments. Whereas nature
has developed these materials over millions of years we are slowly
catching up in a much shorter period."

Among their many potential applications are:
* Time-temperature indicators (TTI) for intelligent packaging -- The
sensors are able to give a visual indication if perishables, such
as food or pharmaceuticals, have experienced undesirable
time-temperature histories. The crystals are extremely sensitive to
even a small rise in temperature between 20 and 100 degrees C.
* Finger print analysis -- Their pressure-responsive shape-memory
characteristics are attractive for biometric and
anti-counterfeiting applications. Pressing the crystals with a bare
finger can reveal fingerprints with high precision showing
well-defined ridges from the skin.
* Bio-sensing -- The photonic crystals can be used as tissue
scaffolds for understanding human biology and disease. If
functionalised with biomolecules could act as highly sensitive
point-of-care testing devices for respiratory viruses offering
inexpensive, reliable, user-friendly biosensing systems.
* Bio/health monitoring -- The sensors mechanochromic response allows
for their application as body sensors which could help improve
technique in sports players.
* Healthcare safety -- Scientists suggest the sensors could be used
in a wrist band which changes colour to indicate to patients if
their healthcare practitioner has washed their hands before
entering an examination room.

The research draws on the Materials Physics Group's (University of
Sussex) expertise in the liquid processing of two-dimensional
nanomaterials, Soft Matter Group's (University of Surrey) experience in
polymer colloids and combines it with expertise at the Advanced
Technology Institute in optical modelling of complex materials. Both
universities are working with the Sussex-based company Advanced
Materials Development (AMD) Ltd to commercialise the technology.

Joseph Keddie, Professor of Soft Matter Physics at the University of
Surrey, said: "Polymer particles are used to manufacture everyday
objects such as inks and paints. In this research, we were able finely
distribute graphene at distances comparable to the wavelengths of
visible light and showed how adding tiny amounts of the two-dimensional
wonder-material leads to emerging new capabilities."

John Lee, CEO of Advanced Materials Development (AMD) Ltd, said: "Given
the versatility of these crystals, this method represents a simple,
inexpensive and scalable approach to produce multi-functional graphene
infused synthetic opals and opens up exciting applications for novel
nanomaterial-based photonics. We are very excited to be able to bring
it to market in near future."
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Story Source:

[17]Materials provided by [18]University of Surrey. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Izabela Jurewicz, Alice A. K. King, Ravi Shanker, Matthew J. Large,
Ronan J. Smith, Ross Maspero, Sean P. Ogilvie, Jurgen Scheerder,
Jun Han, Claudia Backes, Joselito M. Razal, Marian Florescu, Joseph
L. Keddie, Jonathan N. Coleman, Alan B. Dalton. Mechanochromic and
Thermochromic Sensors Based on Graphene Infused Polymer Opals.
Advanced Functional Materials, 2020; 2002473 DOI:
[19]10.1002/adfm.202002473
__________________________________________________________________

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Date:
May 19, 2020

Source:
Chalmers University of Technology

Summary:
Solid state batteries are of great interest to the electric
vehicle industry. Scientists now present a new way of bringing
this promising concept closer to application. An interlayer,
made of a spreadable, 'butter-like' material helps improve the
current density tenfold, while also increasing performance and
safety.

FULL STORY
__________________________________________________________________

Solid state batteries are of great interest to the electric vehicle
industry. Scientists at Chalmers University of Technology, Sweden, and
Xi'an Jiaotong University, China now present a new way of taking this
promising concept closer to large-scale application. An interlayer,
made of a spreadable, 'butter-like' material helps improve the current
density tenfold, while also increasing performance and safety.

"This interlayer makes the battery cell significantly more stable, and
therefore able to withstand much higher current density. What is also
important is that it is very easy to apply the soft mass onto the
lithium metal anode in the battery -- like spreading butter on a
sandwich," says researcher Shizhao Xiong at the Department of Physics
at Chalmers.

Alongside Chalmers Professor Aleksandar Matic and Professor Song's
research group in Xi'an, Shizhao Xiong has been working for a long time
on crafting a suitable interlayer to stabilise the interface for solid
state batteries. The new results were recently presented in the
scientific journal Advanced Functional Materials.

Solid state batteries could revolutionise electric transport. Unlike
today's lithium-ion batteries, solid-state batteries have a solid
electrolyte and therefore contain no environmentally harmful or
flammable liquids.

Simply put, a solid-state battery can be likened to a dry sandwich. A
layer of the metal lithium acts as a slice of bread, and a ceramic
substance is laid on top like a filling. This hard substance is the
solid electrolyte of the battery, which transports lithium ions between
the electrodes of the battery. But the 'sandwich' is so dry, it is
difficult to keep it together -- and there are also problems caused by
the compatibility between the 'bread' and the 'topping'. Many
researchers around the world are working to develop suitable
resolutions to address this problem.

The material which the researchers in Gothenburg and Xi'an are now
working with is a soft, spreadable, 'butter-like' substance, made of
nanoparticles of the ceramic electrolyte, LAGP, mixed with an ionic
liquid. The liquid encapsulates the LAGP particles and makes the
interlayer soft and protective. The material, which has a similar
texture to butter from the fridge, fills several functions and can be
spread easily.

Although the potential of solid-state batteries is very well known,
there is as yet no established way of making them sufficiently stable,
especially at high current densities, when a lot of energy is extracted
from a battery cell very quickly, that is at fast charge or discharge.
The Chalmers researchers see great potential in the development of this
new interlayer.

"This is an important step on the road to being able to manufacture
large-scale, cost-effective, safe and environmentally friendly
batteries that deliver high capacity and can be charged and discharged
at a high rate," says Aleksandar Matic, Professor at the Department of
Physics at Chalmers, who predicts that solid state batteries will be on
the market within five years.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Chalmers University of Technology. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Shizhao Xiong, Yangyang Liu, Piotr Jankowski, Qiao Liu, Florian
Nitze, Kai Xie, Jiangxuan Song, Aleksandar Matic. Design of a
Multifunctional Interlayer for NASCION-Based Solid-State Li Metal
Batteries. Advanced Functional Materials, 2020; 2001444 DOI:
[19]10.1002/adfm.202001444
__________________________________________________________________

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quantum world

Date:
May 19, 2020

Source:
Iowa State University

Summary:
Scientists are using light waves to accelerate supercurrents to
access the unique and potentially useful properties of the
quantum world.

FULL STORY
__________________________________________________________________

Scientists are using light waves to accelerate supercurrents and access
the unique properties of the quantum world, including forbidden light
emissions that one day could be applied to high-speed, quantum
computers, communications and other technologies.

The scientists have seen unexpected things in supercurrents --
electricity that moves through materials without resistance, usually at
super cold temperatures -- that break symmetry and are supposed to be
forbidden by the conventional laws of physics, said Jigang Wang, a
professor of physics and astronomy at Iowa State University, a senior
scientist at the U.S. Department of Energy's Ames Laboratory and the
leader of the project.

Wang's lab has pioneered use of light pulses at terahertz frequencies-
trillions of pulses per second -- to accelerate electron pairs, known
as Cooper pairs, within supercurrents. In this case, the researchers
tracked light emitted by the accelerated electrons pairs. What they
found were "second harmonic light emissions," or light at twice the
frequency of the incoming light used to accelerate electrons.

That, Wang said, is analogous to color shifting from the red spectrum
to the deep blue.

"These second harmonic terahertz emissions are supposed to be forbidden
in superconductors," he said. "This is against the conventional
wisdom."

Wang and his collaborators -- including Ilias Perakis, professor and
chair of physics at the University of Alabama at Birmingham and
Chang-beom Eom, the Raymond R. Holton Chair for Engineering and
Theodore H. Geballe Professor at the University of Wisconsin-Madison --
report their discovery in a research paper just published online by the
scientific journal Physical Review Letters.

"The forbidden light gives us access to an exotic class of quantum
phenomena -- that's the energy and particles at the small scale of
atoms -- called forbidden Anderson pseudo-spin precessions," Perakis
said.

(The phenomena are named after the late Philip W. Anderson, co-winner
of the 1977 Nobel Prize in Physics who conducted theoretical studies of
electron movements within disordered materials such as glass that lack
a regular structure.)

Wang's recent studies have been made possible by a tool called quantum
terahertz spectroscopy that can visualize and steer electrons. It uses
terahertz laser flashes as a control knob to accelerate supercurrents
and access new and potentially useful quantum states of matter. The
National Science Foundation has supported development of the instrument
as well as the current study of forbidden light.

The scientists say access to this and other quantum phenomena could
help drive major innovations:
* "Just like today's gigahertz transistors and 5G wireless routers
replaced megahertz vacuum tubes or thermionic valves over half a
century ago, scientists are searching for a leap forward in design
principles and novel devices in order to achieve quantum computing
and communication capabilities," said Perakis, with Alabama at
Birmingham. "Finding ways to control, access and manipulate the
special characteristics of the quantum world and connect them to
real-world problems is a major scientific push these days. The
National Science Foundation has included quantum studies in its '10
Big Ideas' for future research and development critical to our
nation."
* Wang said, "The determination and understanding of symmetry
breaking in superconducting states is a new frontier in both
fundamental quantum matter discovery and practical quantum
information science. Second harmonic generation is a fundamental
symmetry probe. This will be useful in the development of future
quantum computing strategies and electronics with high speeds and
low energy consumption."

Before they can get there, though, researchers need to do more
exploring of the quantum world. And this forbidden second harmonic
light emission in superconductors, Wang said, represents "a fundamental
discovery of quantum matter."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Iowa State University. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. C. Vaswani, M. Mootz, C. Sundahl, D. H. Mudiyanselage, J. H. Kang,
X. Yang, D. Cheng, C. Huang, R. H. J. Kim, Z. Liu, L. Luo, I. E.
Perakis, C. B. Eom, and J. Wang. Terahertz Second-Harmonic
Generation from Lightwave Acceleration of Symmetry-Breaking
Nonlinear Supercurrents. Physical Review Letters, 2020 DOI:
[19]10.1103/PhysRevLett.124.207003
__________________________________________________________________

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Date:
May 19, 2020

Source:
Helmholtz-Zentrum Dresden-Rossendorf

Summary:
Higher frequencies mean faster data transfer and more powerful
processors. Technically, however, it is anything but easy to
keep increasing clock rates and radio frequencies. New materials
could solve the problem. Experiments have now produced a
promising result: Researchers were able to get a novel material
to increase the frequency of a terahertz radiation flash by a
factor of seven: a first step for potential IT applications.

FULL STORY
__________________________________________________________________

Higher frequencies mean faster data transfer and more powerful
processors -- the formula that has been driving the IT industry for
years. Technically, however, it is anything but easy to keep increasing
clock rates and radio frequencies. New materials could solve the
problem. Experiments at Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
have now produced a promising result: An international team of
researchers was able to get a novel material to increase the frequency
of a terahertz radiation flash by a factor of seven: a first step for
potential IT applications, as the group reports in the journal Nature
Communications.

When smartphones receive data and computer chips perform calculations,
such processes always involve alternating electric fields that send
electrons on clearly defined paths. Higher field frequencies mean that
electrons can do their job faster, enabling higher data transfer rates
and greater processor speeds. The current ceiling is the terahertz
range, which is why researchers all over the world are keen to
understand how terahertz fields interact with novel materials. "Our
TELBE terahertz facility at HZDR is an outstanding source for studying
these interactions in detail and identifying promising materials," says
Jan-Christoph Deinert from HZDR's Institute of Radiation Physics. "A
possible candidate is cadmium arsenide, for example."

The physicist has studied this compound alongside researchers from
Dresden, Cologne, and Shanghai. Cadmium arsenide (Cd3As2) belongs to
the group of so-called three-dimensional Dirac materials, in which
electrons can interact very quickly and efficiently, both with each
other and with rapidly oscillating alternating electric fields. "We
were particularly interested in whether the cadmium arsenide also emits
terahertz radiation at new, higher frequencies," explains TELBE
beamline scientist Sergey Kovalev. "We have already observed this very
successfully in graphene, a two-dimensional Dirac material." The
researchers suspected that cadmium arsenide's three-dimensional
electronic structure would help attain high efficiency in this
conversion.

In order to test this, the experts used a special process to produce
ultra-thin high-purity platelets from cadmium arsenide, which they then
subjected to terahertz pulses from the TELBE facility. Detectors behind
the back of the platelet recorded how the cadmium arsenide reacted to
the radiation pulses. The result: "We were able to show that cadmium
arsenide acts as a highly effective frequency multiplier and does not
lose its efficiency, not even under the very strong terahertz pulses
that can be generated at TELBE," reports former HZDR researcher Zhe
Wang, who now works at the University of Cologne. The experiment was
the first ever to demonstrate the phenomenon of terahertz frequency
multiplication up to the seventh harmonic in this still young class of
materials.

Electrons dance to their own beat

In addition to the experimental evidence, the team together with
researchers form the Max Planck Institute for the Physics of Complex
Systems also provided a detailed theoretical description of what
occurred: The terahertz pulses that hit the cadmium arsenide generate a
strong electric field. "This field accelerates the free electrons in
the material," Deinert describes. "Imagine a huge number of tiny steel
pellets rolling around on a plate that is being tipped from side to
side very fast."

The electrons in the cadmium arsenide respond to this acceleration by
emitting electromagnetic radiation. The crucial thing is that they do
not exactly follow the rhythm of the terahertz field, but oscillate on
rather more complicated paths, which is a consequence of the material's
unusual electronic structure. As a result, the electrons emit new
terahertz pulses at odd integer multiples of the original frequency --
a non-linear effect similar to a piano: When you hit the A key on the
keyboard, the instrument not only sounds the key you played, but also a
rich spectrum of overtones, the harmonics.

For a post 5G-world

The phenomenon holds promise for numerous future applications, for
example in wireless communication, which trends towards ever higher
radio frequencies that can transmit far more data than today's
conventional channels. The industry is currently rolling out the 5G
standard. Components made of Dirac materials could one day use even
higher frequencies -- and thus enable even greater bandwidth than 5G.
The new class of materials also seems to be of interest for future
computers as Dirac-based components could, in theory, facilitate higher
clock rates than today's silicon-based technologies.

But first, the basic science behind it requires further study. "Our
research result was only the first step," stresses Zhe Wang. "Before we
can envision concrete applications, we need to increase the efficiency
of the new materials." To this end, the experts want to find out how
well they can control frequency multiplication by applying an electric
current. And they want to dope their samples, i.e. enrich them with
foreign atoms, in the hope of optimizing nonlinear frequency
conversion.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Helmholtz-Zentrum Dresden-Rossendorf.
Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Sergey Kovalev, Renato M. A. Dantas, Semyon Germanskiy,
Jan-Christoph Deinert, Bertram Green, Igor Ilyakov, Nilesh Awari,
Min Chen, Mohammed Bawatna, Jiwei Ling, Faxian Xiu, Paul H. M. van
Loosdrecht, Piotr Surówka, Takashi Oka, Zhe Wang. Non-perturbative
terahertz high-harmonic generation in the three-dimensional Dirac
semimetal Cd3As2. Nature Communications, 2020; 11 (1) DOI:
[19]10.1038/s41467-020-16133-8
__________________________________________________________________

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Date:
May 19, 2020

Source:
Institute of Industrial Science, The University of Tokyo

Summary:
Researchers have created a way for artificial neuronal networks
to communicate with biological neuronal networks. The new system
converts artificial electrical spiking signals to a visual
pattern than is then used to entrain the real neurons via
optogenetic stimulation of the network. This advance will be
important for future neuroprosthetic devices that replace
damages neurons with artificial neuronal circuitry.

FULL STORY
__________________________________________________________________

Researchers have created a way for artificial neuronal networks to
communicate with biological neuronal networks. The new system converts
artificial electrical spiking signals to a visual pattern than is then
used to entrain the real neurons via optogenetic stimulation of the
network. This advance will be important for future neuroprosthetic
devices that replace damages neurons with artificial neuronal
circuitry.

A prosthesis is an artificial device that replaces an injured or
missing part of the body. You can easily imagine a stereotypical pirate
with a wooden leg or Luke Skywalker's famous robotic hand. Less
dramatically, think of old-school prosthetics like glasses and contact
lenses that replace the natural lenses in our eyes. Now try to imagine
a prosthesis that replaces part of a damaged brain. What could
artificial brain matter be like? How would it even work?

Creating neuroprosthetic technology is the goal of an international
team led by by the Ikerbasque Researcher Paolo Bonifazi from Biocruces
Health Research Institute (Bilbao, Spain), and Timothée Levi from
Institute of Industrial Science, The University of Tokyo and from IMS
lab, University of Bordeaux. Although several types of artificial
neurons have been developed, none have been truly practical for
neuroprostheses. One of the biggest problems is that neurons in the
brain communicate very precisely, but electrical output from the
typical electrical neural network is unable to target specific neurons.
To overcome this problem, the team converted the electrical signals to
light. As Levi explains, "advances in optogenetic technology allowed us
to precisely target neurons in a very small area of our biological
neuronal network."

Optogenetics is a technology that takes advantage of several
light-sensitive proteins found in algae and other animals. Inserting
these proteins into neurons is a kind of hack; once they are there,
shining light onto a neuron will make it active or inactive, depending
on the type of protein. In this case, the researchers used proteins
that were activated specifically by blue light. In their experiment,
they first converted the electrical output of the spiking neuronal
network into the checkered pattern of blue and black squares. Then,
they shined this pattern down onto a 0.8 by 0.8 mm square of the
biological neuronal network growing in the dish. Within this square,
only neurons hit by the light coming from the blue squares were
directly activated.

Spontaneous activity in cultured neurons produces synchronous activity
that follows a certain kind of rhythm. This rhythm is defined by the
way the neurons are connected together, the types of neurons, and their
ability to adapt and change.

"The key to our success," says Levi, "was understanding that the
rhythms of the artificial neurons had to match those of the real
neurons. Once we were able to do this, the biological network was able
to respond to the "melodies" sent by the artificial one. Preliminary
results obtained during the European Brainbow project, help us to
design these biomimetic artificial neurons."

They tuned the artificial neuronal network to use several different
rhythms until they found the best match. Groups of neurons were
assigned to specific pixels in the image grid and the rhythmic activity
was then able to change the visual pattern that was shined onto the
cultured neurons. The light patterns were shown onto a very small area
of the cultured neurons, and the researchers were able to verify local
reactions as well as changes in the global rhythms of the biological
network.

"Incorporating optogenetics into the system is an advance towards
practicality," says Levi. "It will allow future biomimetic devices to
communicate with specific types of neurons or within specific neuronal
circuits." The team is optimistic that future prosthetic devices using
their system will be able to replace damaged brain circuits and restore
communication between brain regions. "At University of Tokyo, in
collaboration with Pr Kohno and Dr Ikeuchi, we are focusing on the
design of bio-hybrid neuromorphic systems to create new generation of
neuroprosthesis," says Levi.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Institute of Industrial Science, The
University of Tokyo. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Yossi Mosbacher, Farad Khoyratee, Miri Goldin, Sivan Kanner,
Yenehaetra Malakai, Moises Silva, Filippo Grassia, Yoav Ben Simon,
Jesus Cortes, Ari Barzilai, Timothée Levi, Paolo Bonifazi. Toward
neuroprosthetic real-time communication from in silico to
biological neuronal network via patterned optogenetic stimulation.
Scientific Reports, 2020; 10 (1) DOI:
[19]10.1038/s41598-020-63934-4
__________________________________________________________________

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Date:
April 30, 2020

Source:
North Carolina State University

Summary:
Engineering researchers have created ultrathin, stretchable
electronic material that is gas permeable, allowing the material
to 'breathe.' The material was designed specifically for use in
biomedical or wearable technologies, since the gas permeability
allows sweat and volatile organic compounds to evaporate away
from the skin, making it more comfortable for users --
especially for long-term wear.

FULL STORY
__________________________________________________________________

Engineering researchers have created ultrathin, stretchable electronic
material that is gas permeable, allowing the material to "breathe." The
material was designed specifically for use in biomedical or wearable
technologies, since the gas permeability allows sweat and volatile
organic compounds to evaporate away from the skin, making it more
comfortable for users -- especially for long-term wear.

"The gas permeability is the big advance over earlier stretchable
electronics," says Yong Zhu, co-corresponding author of a paper on the
work and a professor of mechanical and aerospace engineering at North
Carolina State University. "But the method we used for creating the
material is also important because it's a simple process that would be
easy to scale up."

Specifically, the researchers used a technique called the breath figure
method to create a stretchable polymer film featuring an even
distribution of holes. The film is coated by dipping it in a solution
that contains silver nanowires. The researchers then heat-press the
material to seal the nanowires in place.

"The resulting film shows an excellent combination of electric
conductivity, optical transmittance and water-vapor permeability," Zhu
says. "And because the silver nanowires are embedded just below the
surface of the polymer, the material also exhibits excellent stability
in the presence of sweat and after long-term wear."

"The end result is extremely thin -- only a few micrometers thick,"
says Shanshan Yao, co-author of the paper and a former postdoctoral
researcher at NC State who is now on faculty at Stony Brook University.
"This allows for better contact with the skin, giving the electronics a
better signal-to-noise ratio.

"And gas permeability of wearable electronics is important for more
than just comfort," Yao says. "If a wearable device is not gas
permeable, it can also cause skin irritation."

To demonstrate the material's potential for use in wearable
electronics, the researchers developed and tested prototypes for two
representative applications.

The first prototype consisted of skin-mountable, dry electrodes for use
as electrophysiologic sensors. These have multiple potential
applications, such as measuring electrocardiography (ECG) and
electromyography (EMG) signals.

"These sensors were able to record signals with excellent quality, on
par with commercially available electrodes," Zhu says.

The second prototype demonstrated textile-integrated touch sensing for
human-machine interfaces. The authors used a wearable textile sleeve
integrated with the porous electrodes to play computer games such as
Tetris.

"If we want to develop wearable sensors or user interfaces that can be
worn for a significant period of time, we need gas-permeable electronic
materials," Zhu says. "So this is a significant step forward."
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Story Source:

[17]Materials provided by [18]North Carolina State University. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Weixin Zhou, Shanshan Yao, Hongyu Wang, Qingchuan Du, Yanwen Ma,
Yong Zhu. Gas-Permeable, Ultrathin, Stretchable Epidermal
Electronics with Porous Electrodes. ACS Nano, 2020; DOI:
[19]10.1021/acsnano.0c00906
__________________________________________________________________

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Mathematical model can predict cumulative deaths in US

Date:
April 30, 2020

Source:
Rutgers University

Summary:
A new mathematical model has been created to estimate the death
toll linked to the COVID-19 pandemic in the United States and
could be used around the world.

FULL STORY
__________________________________________________________________

A Rutgers engineer has created a mathematical model that accurately
estimates the death toll linked to the COVID-19 pandemic in the United
States and could be used around the world.

"Based on data available on April 28, the model showed that the
COVID-19 pandemic might be over in the United States, meaning no more
American deaths, by around late June 2020," said Hoang Pham, a
distinguished professor in the Department of Industrial and Systems
Engineering in the School of Engineering at Rutgers University-New
Brunswick. "But if testing and contact tracing strategies,
social-distancing policies, reopening of community strategies or
stay-at-home policies change significantly in the coming days and
weeks, the predicted death toll will also change."

The model, detailed in a study published in the journal Mathematics,
predicted the death toll would eventually reach about 68,120 in the
United States as a result of the SARS-CoV-2 coronavirus that causes
COVID-19. That's based on data available on April 28, and there was
high confidence (99 percent) the expected death toll would be between
66,055 and 70,304.

The model's estimates and predictions closely match reported death
totals. As of April 29, more than 58,000 Americans had succumbed to
COVID-19, according to the Johns Hopkins University COVID-19 Tracking
Map.

The next steps include applying the model to global COVID-19 death data
as well as to other nations such as Italy and Spain, both of which have
experienced thousands of deaths due to COVID-19. The model could also
be used to evaluate population mortality and the spread of other
diseases.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Rutgers University. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Hoang Pham. On Estimating the Number of Deaths Related to Covid-19.
Mathematics, 2020; 8 (5): 655 DOI: [19]10.3390/math8050655
__________________________________________________________________

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Computer models of merging neutron stars predicts how to tell when this
happens

Date:
April 30, 2020

Source:
Goethe University Frankfurt

Summary:
According to modern particle physics, matter produced when
neutron stars merge is so dense that it could exist in a state
of dissolved elementary particles. This state of matter, called
quark-gluon plasma, might produce a specific signature in
gravitational waves. Physicists have now calculated this process
using supercomputers.

FULL STORY
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Neutron stars are among the densest objects in the universe. If our
Sun, with its radius of 700,000 kilometres were a neutron star, its
mass would be condensed into an almost perfect sphere with a radius of
around 12 kilometres. When two neutron stars collide and merge into a
hyper-massive neutron star, the matter in the core of the new object
becomes incredibly hot and dense. According to physical calculations,
these conditions could result in hadrons such as neutrons and protons,
which are the particles normally found in our daily experience,
dissolving into their components of quarks and gluons and thus
producing a quark-gluon plasma.

In 2017 it was discovered for the first time that merging neutron stars
send out a gravitational wave signal that can be detected on Earth. The
signal not only provides information on the nature of gravity, but also
on the behaviour of matter under extreme conditions. When these
gravitational waves were first discovered in 2017, however, they were
not recorded beyond the merging point.

This is where the work of the Frankfurt physicists begins. They
simulated merging neutron stars and the product of the merger to
explore the conditions under which a transition from hadrons to a
quark-gluon plasma would take place and how this would affect the
corresponding gravitational wave. The result: in a specific, late phase
of the life of the merged object a phase transition to the quark-gluon
plasma took place and left a clear and characteristic signature on the
gravitational-wave signal.

Professor Luciano Rezzolla from Goethe University is convinced:
"Compared to previous simulations, we have discovered a new signature
in the gravitational waves that is significantly clearer to detect. If
this signature occurs in the gravitational waves that we will receive
from future neutron-star mergers, we would have a clear evidence for
the creation of quark-gluon plasma in the present universe."
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Story Source:

[17]Materials provided by [18]Goethe University Frankfurt. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Lukas R. Weih, Matthias Hanauske, Luciano Rezzolla. Post-merger
gravitational wave signatures of phase transitions in binary
mergers. Physical Review Letters, 2020 DOI:
[19]10.1103/PhysRevLett.124.171103
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Date:
April 30, 2020

Source:
Tohoku University

Summary:
A multinational team of researchers has revealed the magnetic
states of nanoscale gyroids, 3D chiral network-like
nanostructures. The findings add a new candidate system for
research into unconventional information processing and emergent
phenomena relevant to spintronics.

FULL STORY
__________________________________________________________________

A multinational team of researchers from Tohoku University and
institutions in the UK, Germany and Switzerland has revealed the
magnetic states of nanoscale gyroids, 3D chiral network-like
nanostructures. The findings add a new candidate system for research
into unconventional information processing and emergent phenomena
relevant to spintronics.

Arrays of interacting nanostructures offer the ability to realize
unprecedented material properties, as interactions can give rise to
new, "emergent" phenomena. In magnetism, such emergent phenomena have
so far only been demonstrated in 2D, in artificial spin ices and
magnonic crystals. However, progress towards realizing magnetic
"metamaterials", which could form the basis of advanced spintronic
devices by displaying emergent effects in 3D, has been hampered by two
obstacles. The first is the need to fabricate complex 3D building
blocks at dimensions smaller than 100 nm (comparable to intrinsic
magnetic lengthscales) and the second is the challenge of visualizing
their magnetic configurations.

The research team therefore decided to study nanoscale magnetic
gyroids, 3D networks composed of 3 connected vertices defined by triads
of curved nanowire-like struts (Figure 1). Gyroids have attracted much
interest, as despite their complexity they can self-assemble from a
carefully formulated combination of polymers, which can be used as a 3D
mold or template to form free-standing nanostructures (Figure 2). As
the struts connect to form spirals, gyroids have a "handedness" or
chirality, and their shape makes magnetic gyroids ideal systems to test
predictions of new magnetic properties emerging from curvature.
Measurements of the optical properties of gyroids even showed that
gyroids can have topological properties, which along with chiral
effects are currently the subject of intense study to develop new
classes of spintronic devices. However, the magnetic states which might
exist in gyroids had not yet been established, leading to the present
study.

The researchers produced Ni[75]Fe[25] single-gyroid and double-gyroid
(formed from a mirror-image pair of single-gyroids) nanostructures with
11 nm diameter struts and a 42 nm unit cell, via block co-polymer
templating and electrodeposition. These dimensions are comparable to
domain wall widths and spin wave wavelengths in Ni-Fe. They then imaged
the gyroid nanoparticles with off-axis electron holography, which could
map the magnetization and stray magnetic field patterns in and around
the gyroids' struts with nanometer spatial resolution. Analysis of the
patterns with the aid of finite-element micromagnetic simulations
revealed a very intricate magnetic state which is overall ferromagnetic
but without a unique equilibrium configuration (Figure 3), implying
that a magnetic gyroid can adopt a large number of stable states.

"These findings establish magnetic gyroids as a candidate of interest
for applications such as reservoir computing and spin-wave logic," said
lead author Justin Llandro." The research takes an exciting first step
towards 3D nanoscale magnetic metamaterials which can be used to
uncover new emergent effects and advance both fundamental and applied
spintronics research."


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[17]Materials provided by [18]Tohoku University. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Justin Llandro, David M. Love, András Kovács, Jan Caron, Kunal N.
Vyas, Attila Kákay, Ruslan Salikhov, Kilian Lenz, Jürgen
Fassbender, Maik R. J. Scherer, Christian Cimorra, Ullrich Steiner,
Crispin H. W. Barnes, Rafal E. Dunin-Borkowski, Shunsuke Fukami,
Hideo Ohno. Visualizing Magnetic Structure in 3D Nanoscale Ni–Fe
Gyroid Networks. Nano Letters, 2020; DOI:
[19]10.1021/acs.nanolett.0c00578
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hope

Date:
April 30, 2020

Source:
University of Sussex

Summary:
A mass move to working-from-home accelerated by the coronavirus
pandemic might not be as beneficial to the planet as many hope,
according to a new study.

FULL STORY
__________________________________________________________________

A mass move to working-from-home accelerated by the Coronavirus
pandemic might not be as beneficial to the planet as many hope,
according to a new study by the Centre for Research into Energy Demand
Solutions (CREDS).

The majority of studies on the subject analysed by University of Sussex
academics agree that working-from-home reduced commuter travel and
energy use -- by as much as 80% in some cases.

But a small number of studies found that telecommuting increased energy
use or had a negligible impact, since the energy savings were offset by
increased travel for recreation or other purposes, together with
additional energy use in the home.

The authors found that more methodologically rigorous studies were less
likely to estimate energy savings -- all six of the studies analysed
that found negligible energy reductions or increases were judged to be
methodologically good.

Dr Andrew Hook, Lecturer in Human Geography at the University of
Sussex, said:

"While most studies conclude that teleworking can contribute energy
savings, the more rigorous studies and those with a broader scope
present more ambiguous findings. Where studies include additional
impacts, such as non-work travel or office and home energy use, the
potential energy savings appear more limited -- with some studies
suggesting that, in the context of growing distances between the
workplace and home, part-week teleworking could lead to a net increase
in energy consumption."

Dr Victor Court, Lecturer at the Center for Energy Economics and
Management, IFP School, said:

"It is our belief from examining the relevant literature that
teleworking has some potential to reduce energy consumption and
associated emissions -- both through reducing commuter travel and
displacing office-related energy consumption. But if it encourages
people to live further away from work or to take additional trips, the
savings could be limited or even negative."

Studies indicate it would be better for workers to continue working
from home for all of the working week rather than splitting time
between office and home once lockdown rules are relaxed. Similarly,
companies will need to encourage the majority of staff to switch to
home working and to downsize office space to ensure significant energy
savings.

Even the mass migration of workers to home working might have only a
small impact on overall energy usage. One study noted that even if all
US information workers teleworked for four days a week, the drop in
national energy consumption would be significantly less effective than
a 20% improvement in car fuel efficiency.

The study also warns that technological advances could erode some of
the energy savings due to the short lifetime and rapid replacement of
ICTs, their increasingly complex supply chains, their dependence on
rare earth elements and the development of energy-intensive processes
such as cloud storage and video streaming.

The authors add that modern-day work patterns are becoming increasingly
complex, diversified and personalised, making it harder to track
whether teleworking is definitively contributing energy savings.

Steven Sorrell, Professor of Energy Policy at the Science Policy
Research Unit, University of Sussex, said:

"While the lockdown has clearly reduced energy consumption, only some
of those savings will be achieved in more normal patterns of
teleworking. To assess whether teleworking is really sustainable, we
need to look beyond the direct impact on commuting and investigate how
it changes a whole range of daily activities."

The paper, published in Environmental Research Letters, provides a
systematic review of current knowledge of the energy impacts of
teleworking, synthesising the results of 39 empirical studies from the
US, Europe, Thailand, Malaysia and Iran published between 1995 and
2019.

Among the potential energy increases from working-from-home practices
the study identified include:

Teleworkers living further away from their place of work so making
longer commutes on days they worked in the office -- one study found UK
teleworkers have a 10.7 mile longer commute than those who travelled
into work every day.

The time gained from not participating in daily commute used by
teleworkers to make additional journeys for leisure and social
purposes.

Teleworking households' spending money saved from the daily commute on
goods, activities and services also requiring energy and producing
emissions.

Isolated and sedentary teleworkers taking on more journeys to combat
negative feelings.

Other household members making trips in cars freed up from the daily
commute

Benjamin K Sovacool, Professor of Energy Policy at the Science Policy
Research Unit, University of Sussex, said:

"The body of research on the subject shows that it is too simple to
assume that teleworking is inevitably a more sustainable option. Unless
workers and employers fully commit to the working from home model, many
of the potential energy savings could be lost. A scenario after the
threat of Coronavirus has cleared where workers will want the best of
both worlds; retaining the freedom and flexibility they found from
working from home but the social aspects of working at an office that
they've missed out on during lockdown, will not deliver the energy
savings the world needs."
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Story Source:

[17]Materials provided by [18]University of Sussex. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Andrew Hook, Victor Court, Benjamin Sovacool, Steven Sorrell. A
systematic review of the energy and climate impacts of teleworking.
Environmental Research Letters, 2020; DOI:
[19]10.1088/1748-9326/ab8a84
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Date:
May 11, 2020

Source:
Royal Ontario Museum

Summary:
New research on a rock collected by the Apollo 17 astronauts has
revealed evidence for a mineral phase that can only form above
2300 °C. Such temperatures are uniquely achieved in melt sheets
following a meteorite impact, allowing the researchers to link
the 4.33-billion-year-old crystal to an ancient collision on the
Moon. The study opens the door for many of the more complex
rocks on the Moon to have formed in these destructive
environments.

FULL STORY
__________________________________________________________________

New research published today in the journal Nature Astronomy reveals a
type of destructive event most often associated with disaster movies
and dinosaur extinction may have also contributed to the formation of
the Moon's surface.

A group of international scientists led by the Royal Ontario Museum has
discovered that the formation of ancient rocks on the Moon may be
directly linked to large-scale meteorite impacts.

The scientists conducted new research of a unique rock collected by
NASA astronauts during the 1972 Apollo 17 mission to the Moon. They
found it contains mineralogical evidence that it formed at incredibly
high temperatures (in excess of 2300 °C/ 4300 °F) that can only be
achieved by the melting of the outer layer of a planet in a large
impact event.

In the rock, the researchers discovered the former presence of cubic
zirconia, a mineral phase often used as a substitute for diamond in
jewellery. The phase would only form in rocks heated to above 2300 °C,
and though it has since reverted to a more stable phase (the mineral
known as baddeleyite), the crystal retains distinctive evidence of a
high-temperature structure. An interactive image of the complex crystal
used in the study can be seen here using the Virtual Microscope.

While looking at the structure of the crystal, the researchers also
measured the age of the grain, which reveals the baddeleyite formed
over 4.3 billion years ago. It was concluded that the high-temperature
cubic zirconia phase must have formed before this time, suggesting that
large impacts were critically important to forming new rocks on the
early Moon.

Fifty years ago, when the first samples were brought back from the
surface of the Moon, lunar scientists raised questions about how lunar
crustal rocks formed. Even today, a key question remains unanswered:
how did the outer and inner layers of the Moon mix after the Moon
formed? This new research suggests that large impacts over 4 billion
years ago could have driven this mixing, producing the complex range of
rocks seen on the surface of the Moon today.

"Rocks on Earth are constantly being recycled, but the Moon doesn't
exhibit plate tectonics or volcanism, allowing older rocks to be
preserved," explains Dr. Lee White, Hatch Postdoctoral Fellow at the
ROM. "By studying the Moon, we can better understand the earliest
history of our planet. If large, super-heated impacts were creating
rocks on the Moon, the same process was probably happening here on
Earth."

"By first looking at this rock, I was amazed by how differently the
minerals look compared to other Apollo 17 samples," says Dr. Ana
Cernok, Hatch Postdoctoral Fellow at the ROM and co-author of the
study. "Although smaller than a millimetre, the baddeleyite grain that
caught our attention was the largest one I have ever seen in Apollo
samples. This small grain is still holding the evidence for formation
of an impact basin that was hundreds of kilometres in diameter. This is
significant, because we do not see any evidence of these old impacts on
Earth."

Dr. James Darling, a reader at the University of Portsmouth and
co-author of the study, says the findings completely change scientists'
understanding of the samples collected during the Apollo missions, and,
in effect, the geology of the Moon. "These unimaginably violent
meteorite impacts helped to build the lunar crust, not only destroy
it," he says.
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__________________________________________________________________

Story Source:

[19]Materials provided by [20]Royal Ontario Museum. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. L. F. White, A. Černok, J. R. Darling, M. J. Whitehouse, K. H. Joy,
C. Cayron, J. Dunlop, K. T. Tait, M. Anand. Evidence of extensive
lunar crust formation in impact melt sheets 4,330 Myr ago. Nature
Astronomy, 2020; DOI: [21]10.1038/s41550-020-1092-5
__________________________________________________________________

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to early life

The oldest molecular fluids in the solar system could have supported the
rapid formation and evolution of the building blocks of life

Date:
May 11, 2020

Source:
Royal Ontario Museum

Summary:
Scientists have analyzed a meteorite atom by atom to reveal the
chemistry and acidity of the earliest fluids in the solar
system. By finding evidence of sodium-rich alkaline water in the
Tagish Lake meteorite, this new study suggests amino acids could
have formed rapidly on the parent asteroid, opening the door for
the early evolution of microbial life.

FULL STORY
__________________________________________________________________

The oldest molecular fluids in the solar system could have supported
the rapid formation and evolution of the building blocks of life, new
research in the journal Proceedings of the National Academy of Sciences
reveals.

An international group of scientists, led by researchers from the Royal
Ontario Museum (ROM) and co-authors from McMaster University and York
University, used state-of-the-art techniques to map individual atoms in
minerals formed in fluids on an asteroid over 4.5 billion years ago.

Studying the ROM's iconic Tagish Lake meteorite, scientists used
atom-probe tomography, a technique capable of imaging atoms in 3D, to
target molecules along boundaries and pores between magnetite grains
that likely formed on the asteroid's crust. There, they discovered
water precipitates left in the grain boundaries on which they conducted
their ground-breaking research.

"We know water was abundant in the early solar system," explains lead
author Dr. Lee White, Hatch postdoctoral fellow at the ROM, "but there
is very little direct evidence of the chemistry or acidity of these
liquids, even though they would have been critical to the early
formation and evolution of amino acids and, eventually, microbial
life."

This new atomic-scale research provides the first evidence of the
sodium-rich (and alkaline) fluids in which the magnetite framboids
formed. These fluid conditions are preferential for the synthesis of
amino acids, opening the door for microbial life to form as early as
4.5 billion years ago.

"Amino acids are essential building blocks of life on Earth, yet we
still have a lot to learn about how they first formed in our solar
system," says Beth Lymer, a PhD student at York University and
co-author of the study. "The more variables that we can constrain, such
as temperature and pH, allows us to better understand the synthesis and
evolution of these very important molecules into what we now know as
biotic life on Earth."

The Tagish Lake carbonaceous chondrite was retrieved from an ice sheet
in B.C.'s Tagish Lake in 2000, and later acquired by the ROM, where it
is now considered to be one of the museums iconic objects. This history
means that the sample used by the team has never been above room
temperature or exposed to liquid water, allowing the scientists to
confidently link the measured fluids to the parent asteroid.

By using new techniques, such as atom probe tomography, the scientists
hope to develop analytical methods for planetary materials returned to
Earth by space craft, such as by NASA's OSIRIS-REx mission or a planned
sample-return mission to Mars in the near future.

"Atom probe tomography gives us an opportunity to make fantastic
discoveries on bits of material a thousand times thinner than a human
hair," says White. "Space missions are limited to bringing back tiny
amounts of material, meaning these techniques will be critical to
allowing us to understand more about the solar system while also
preserving material for future generations."
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__________________________________________________________________

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Date:
May 11, 2020

Source:
Southwest Research Institute

Summary:
Scientists have modeled the atmosphere of Mars to help determine
that salty pockets of water present on the Red Planet are likely
not habitable by life as we know it on Earth. The team helped
allay planetary protection concerns about contaminating
potential Martian ecosystems.

FULL STORY
__________________________________________________________________

A Southwest Research Institute scientist modeled the atmosphere of Mars
to help determine that salty pockets of water present on the Red Planet
are likely not habitable by life as we know it on Earth. A team that
also included scientists from Universities Space Research Association
(USRA) and the University of Arkansas helped allay planetary protection
concerns about contaminating potential Martian ecosystems. These
results were published this month in Nature Astronomy.

Due to Mars' low temperatures and extremely dry conditions, a droplet
of liquid water on its surface would instantly freeze, boil or
evaporate, unless the droplet had dissolved salts in it. This brine
would have a lower freezing temperature and would evaporate more slowly
than pure liquid water. Salts are found across Mars, so brines could
form there.

"Our team looked at specific regions on Mars -- areas where liquid
water temperature and accessibility limits could possibly allow known
terrestrial organisms to replicate -- to understand if they could be
habitable," said SwRI's Dr. Alejandro Soto, a senior research scientist
and co-author of the study. "We used Martian climate information from
both atmospheric models and spacecraft measurements. We developed a
model to predict where, when and for how long brines are stable on the
surface and shallow subsurface of Mars."

Mars' hyper-arid conditions require lower temperatures to reach high
relative humidities and tolerable water activities, which are measures
of how easily the water content may be utilized for hydration. The
maximum brine temperature expected is -55 F -- at the boundary of the
theoretical low temperature limit for life.

"Even extreme life on Earth has its limits, and we found that brine
formation from some salts can lead to liquid water over 40% of the
Martian surface but only seasonally, during 2% of the Martian year,"
Soto continued. "This would preclude life as we know it."

While pure liquid water is unstable on the Martian surface, models
showed that stable brines can form and persist from the equator to high
latitudes on the surface of Mars for a few percent of the year for up
to six consecutive hours, a broader range than previously thought.
However, the temperatures are well below the lowest temperatures to
support life.

"These new results reduce some of the risk of exploring the Red Planet
while also contributing to future work on the potential for habitable
conditions on Mars," Soto said.
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Story Source:

[17]Materials provided by [18]Southwest Research Institute. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Edgard G. Rivera-Valentín, Vincent F. Chevrier, Alejandro Soto,
Germán Martínez. Distribution and habitability of (meta)stable
brines on present-day Mars. Nature Astronomy, 2020; DOI:
[19]10.1038/s41550-020-1080-9
__________________________________________________________________

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Ryugu's interaction with the sun changes what we know about asteroid history

Date:
May 11, 2020

Source:
University of Tokyo

Summary:
In February and July of 2019, the Hayabusa2 spacecraft briefly
touched down on the surface of near-Earth asteroid Ryugu. The
readings it took with various instruments at those times have
given researchers insight into the physical and chemical
properties of the 1-kilometer-wide asteroid. These findings
could help explain the history of Ryugu and other asteroids, as
well as the solar system at large.

FULL STORY
__________________________________________________________________

In February and July of 2019, the Hayabusa2 spacecraft briefly touched
down on the surface of near-Earth asteroid Ryugu. The readings it took
with various instruments at those times have given researchers insight
into the physical and chemical properties of the 1-kilometer-wide
asteroid. These findings could help explain the history of Ryugu and
other asteroids, as well as the solar system at large.

When our solar system formed around 5 billion years ago, most of the
material it formed from became the sun, and a fraction of a percent
became the planets and solid bodies, including asteroids. Planets have
changed a lot since the early days of the solar system due to
geological processes, chemical changes, bombardments and more. But
asteroids have remained more or less the same as they are too small to
experience those things, and are therefore useful for researchers who
investigate the early solar system and our origins.

"I believe knowledge of the evolutionary processes of asteroids and
planets are essential to understand the origins of the Earth and life
itself," said Associate Professor Tomokatsu Morota from the Department
of Earth and Planetary Science at the University of Tokyo. "Asteroid
Ryugu presents an amazing opportunity to learn more about this as it is
relatively close to home, so Hayabusa2 could make a return journey
relatively easily. "

Hayabusa2 launched in December 2014 and reached Ryugu in June 2018. At
the time of writing, Hayabusa2 is on its way back to Earth and is
scheduled to deliver a payload in December 2020. This payload consists
of small samples of surface material from Ryugu collected during two
touchdowns in February and July of 2019. Researchers will learn much
from the direct study of this material, but even before it reaches us,
Hayabusa2 helped researchers to investigate the physical and chemical
makeup of Ryugu.

"We used Hayabusa2's ONC-W1 and ONC-T imaging instruments to look at
dusty matter kicked up by the spacecraft's engines during the
touchdowns," said Morota. "We discovered large amounts of very fine
grains of dark-red colored minerals. These were produced by solar
heating, suggesting at some point Ryugu must have passed close by the
sun."

Morota and his team investigated the spatial distribution of the
dark-red matter around Ryugu as well as its spectra or light signature.
The strong presence of the material around specific latitudes
corresponded to the areas that would have received the most solar
radiation in the asteroid's past; hence, the belief that Ryugu must
have passed by the sun.

"From previous studies we know Ryugu is carbon-rich and contains
hydrated minerals and organic molecules. We wanted to know how solar
heating chemically changed these molecules," said Morota. "Our theories
about solar heating could change what we know of orbital dynamics of
asteroids in the solar system. This in turn alters our knowledge of
broader solar system history, including factors that may have affected
the early Earth."

When Hayabusa2 delivers material it collected during both touchdowns,
researchers will unlock even more secrets of our solar history. Based
on spectral readings and albedo, or reflectivity, from within the
touchdown sites, researchers are confident that both dark-red
solar-heated material and gray unheated material were collected by
Hayabusa2. Morota and his team hope to study larger properties of
Ryugu, such as its many craters and boulders.

"I wish to study the statistics of Ryugu's surface craters to better
understand the strength characteristics of its rocks, and history of
small impacts it may have received," said Morota. "The craters and
boulders on Ryugu meant there were limited safe landing locations for
Hayabusa2. Finding a suitable location was hard work and the eventual
first successful touchdown was one of the most exciting events of my
life."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Tokyo. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. T. Morota, S. Sugita, Y. Cho, M. Kanamaru, E. Tatsumi, N. Sakatani,
R. Honda, N. Hirata, H. Kikuchi, M. Yamada, Y. Yokota, S. Kameda,
M. Matsuoka, H. Sawada, C. Honda, T. Kouyama, K. Ogawa, H. Suzuki,
K. Yoshioka, M. Hayakawa, N. Hirata, M. Hirabayashi, H. Miyamoto,
T. Michikami, T. Hiroi, R. Hemmi, O. S. Barnouin, C. M. Ernst, K.
Kitazato, T. Nakamura, L. Riu, H. Senshu, H. Kobayashi, S. Sasaki,
G. Komatsu, N. Tanabe, Y. Fujii, T. Irie, M. Suemitsu, N. Takaki,
C. Sugimoto, K. Yumoto, M. Ishida, H. Kato, K. Moroi, D. Domingue,
P. Michel, C. Pilorget, T. Iwata, M. Abe, M. Ohtake, Y. Nakauchi,
K. Tsumura, H. Yabuta, Y. Ishihara, R. Noguchi, K. Matsumoto, A.
Miura, N. Namiki, S. Tachibana, M. Arakawa, H. Ikeda, K. Wada, T.
Mizuno, C. Hirose, S. Hosoda, O. Mori, T. Shimada, S. Soldini, R.
Tsukizaki, H. Yano, M. Ozaki, H. Takeuchi, Y. Yamamoto, T. Okada,
Y. Shimaki, K. Shirai, Y. Iijima, H. Noda, S. Kikuchi, T.
Yamaguchi, N. Ogawa, G. Ono, Y. Mimasu, K. Yoshikawa, T. Takahashi,
Y. Takei, A. Fujii, S. Nakazawa, F. Terui, S. Tanaka, M. Yoshikawa,
T. Saiki, S. Watanabe, Y. Tsuda. Sample collection from asteroid
(162173) Ryugu by Hayabusa2: Implications for surface evolution.
Science, 2020; 368 (6491): 654 DOI: [19]10.1126/science.aaz6306
__________________________________________________________________

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Date:
May 11, 2020

Source:
King's College London

Summary:
Researchers have developed an artificial intelligence diagnostic
that can predict whether someone is likely to have COVID-19
based on their symptoms.

FULL STORY
__________________________________________________________________

Researchers at King's College London, Massachusetts General Hospital
and health science company ZOE have developed an artificial
intelligence diagnostic that can predict whether someone is likely to
have COVID-19 based on their symptoms. Their findings are published
today in Nature Medicine.

The AI model uses data from the COVID Symptom Study app to predict
COVID-19 infection, by comparing people's symptoms and the results of
traditional COVID tests. Researchers say this may provide help for
populations where access to testing is limited. Two clinical trials in
the UK and the US are due to start shortly.

More than 3.3 million people globally have downloaded the app and are
using it to report daily on their health status, whether they feel well
or have any new symptoms such as persistent cough, fever, fatigue and
loss of taste or smell (anosmia).

In this study, the researchers analysed data gathered from just under
2.5 million people in the UK and US who had been regularly logging
their health status in the app, around a third of whom had logged
symptoms associated with COVID-19. Of these, 18,374 reported having had
a test for coronavirus, with 7,178 people testing positive.

The research team investigated which symptoms known to be associated
with COVID-19 were most likely to be associated with a positive test.
They found a wide range of symptoms compared to cold and flu, and warn
against focusing only on fever and cough. Indeed, they found loss of
taste and smell (anosmia) was particularly striking, with two thirds of
users testing positive for coronavirus infection reporting this symptom
compared with just over a fifth of the participants who tested
negative. The findings suggest that anosmia is a stronger predictor of
COVID-19 than fever, supporting anecdotal reports of loss of smell and
taste as a common symptom of the disease.

The researchers then created a mathematical model that predicted with
nearly 80% accuracy whether an individual is likely to have COVID-19
based on their age, sex and a combination of four key symptoms: loss of
smell or taste, severe or persistent cough, fatigue and skipping meals.
Applying this model to the entire group of over 800,000 app users
experiencing symptoms predicted that just under a fifth of those who
were unwell (17.42%) were likely to have COVID-19 at that time.

Researchers suggest that combining this AI prediction with widespread
adoption of the app could help to identify those who are likely to be
infectious as soon as the earliest symptoms start to appear, focusing
tracking and testing efforts where they are most needed.

Professor Tim Spector from King's College London said: "Our results
suggest that loss of taste or smell is a key early warning sign of
COVID-19 infection and should be included in routine screening for the
disease. We strongly urge governments and health authorities everywhere
to make this information more widely known, and advise anyone
experiencing sudden loss of smell or taste to assume that they are
infected and follow local self-isolation guidelines."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]King's College London. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Cristina Menni, Ana M. Valdes, Maxim B. Freidin, Carole H. Sudre,
Long H. Nguyen, David A. Drew, Sajaysurya Ganesh, Thomas Varsavsky,
M. Jorge Cardoso, Julia S. El-Sayed Moustafa, Alessia Visconti,
Pirro Hysi, Ruth C. E. Bowyer, Massimo Mangino, Mario Falchi,
Jonathan Wolf, Sebastien Ourselin, Andrew T. Chan, Claire J.
Steves, Tim D. Spector. Real-time tracking of self-reported
symptoms to predict potential COVID-19. Nature Medicine, 2020; DOI:
[19]10.1038/s41591-020-0916-2
__________________________________________________________________

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Tiny material differences are crucial for the functional behavior of
memristive devices

Date:
May 11, 2020

Source:
Forschungszentrum Juelich

Summary:
Memristive devices behave similarly to neurons in the brain.
Researchers have now discovered how to systematically control
the functional behaviour of these elements. The smallest
differences in material composition are found crucial:
differences so small that until now experts had failed to notice
them.

FULL STORY
__________________________________________________________________

Scientists around the world are intensively working on memristive
devices, which are capable in extremely low power operation and behave
similarly to neurons in the brain. Researchers from the Jülich Aachen
Research Alliance (JARA) and the German technology group Heraeus have
now discovered how to systematically control the functional behaviour
of these elements. The smallest differences in material composition are
found crucial: differences so small that until now experts had failed
to notice them. The researchers' design directions could help to
increase variety, efficiency, selectivity and reliability for
memristive technology-based applications, for example for
energy-efficient, non-volatile storage devices or neuro-inspired
computers.

Memristors are considered a highly promising alternative to
conventional nanoelectronic elements in computer Chips. Because of the
advantageous functionalities, their development is being eagerly
pursued by many companies and research institutions around the world.
The Japanese corporation NEC installed already the first prototypes in
space satellites back in 2017. Many other leading companies such as
Hewlett Packard, Intel, IBM, and Samsung are working to bring
innovative types of computer and storage devices based on memristive
elements to market.

Fundamentally, memristors are simply "resistors with memory," in which
high resistance can be switched to low resistance and back again. This
means in principle that the devices are adaptive, similar to a synapse
in a biological nervous system. "Memristive elements are considered
ideal candidates for neuro-inspired computers modelled on the brain,
which are attracting a great deal of interest in connection with deep
learning and artificial intelligence," says Dr. Ilia Valov of the Peter
Grünberg Institute (PGI-7) at Forschungszentrum Jülich.

In the latest issue of the open access journal Science Advances, he and
his team describe how the switching and neuromorphic behaviour of
memristive elements can be selectively controlled. According to their
findings, the crucial factor is the purity of the switching oxide
layer. "Depending on whether you use a material that is 99.999999 %
pure, and whether you introduce one foreign atom into ten million atoms
of pure material or into one hundred atoms, the properties of the
memristive elements vary substantially" says Valov.

This effect had so far been overlooked by experts. It can be used very
specifically for designing memristive systems, in a similar way to
doping semiconductors in information technology. "The introduction of
foreign atoms allows us to control the solubility and transport
properties of the thin oxide layers," explains Dr. Christian Neumann of
the technology group Heraeus. He has been contributing his materials
expertise to the project ever since the initial idea was conceived in
2015.

"In recent years there has been remarkable progress in the development
and use of memristive devices, however that progress has often been
achieved on a purely empirical basis," according to Valov. Using the
insights that his team has gained, manufacturers could now methodically
develop memristive elements selecting the functions they need. The
higher the doping concentration, the slower the resistance of the
elements changes as the number of incoming voltage pulses increases and
decreases, and the more stable the resistance remains. "This means that
we have found a way for designing types of artificial synapses with
differing excitability," explains Valov.

Design specification for artificial synapses

The brain's ability to learn and retain information can largely be
attributed to the fact that the connections between neurons are
strengthened when they are frequently used. Memristive devices, of
which there are different types such as electrochemical metallization
cells (ECMs) or valence change memory cells (VCMs), behave similarly.
When these components are used, the conductivity increases as the
number of incoming voltage pulses increases. The changes can also be
reversed by applying voltage pulses of the opposite polarity.

The JARA researchers conducted their systematic experiments on ECMs,
which consist of a copper electrode, a platinum electrode, and a layer
of silicon dioxide between them. Thanks to the cooperation with Heraeus
researchers, the JARA scientists had access to different types of
silicon dioxide: one with a purity of 99.999999 % -- also called 8N
silicon dioxide -- and others containing 100 to 10,000 ppm (parts per
million) of foreign atoms. The precisely doped glass used in their
experiments was specially developed and manufactured by quartz glass
specialist Heraeus Conamic, which also holds the patent for the
procedure. Copper and protons acted as mobile doping agents, while
aluminium and gallium were used as non-volatile doping.

Record switching time confirms theory

Based on their series of experiments, the researchers were able to show
that the ECMs' switching times change as the amount of doping atoms
changes. If the switching layer is made of 8N silicon dioxide, the
memristive component switches in only 1.4 nanoseconds. To date, the
fastest value ever measured for ECMs had been around 10 nanoseconds. By
doping the oxide layer of the components with up to 10,000 ppm of
foreign atoms, the switching time was prolonged into the range of
milliseconds. "We can also theoretically explain our results. This is
helping us to understand the physico-chemical processes on the
nanoscale and apply this knowledge in the practice" says Valov. Based
on generally applicable theoretical considerations, supported by
experimental results, some also documented in the literature, he is
convinced that the doping/impurity effect occurs and can be employed in
all types memristive elements.
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Story Source:

[17]Materials provided by [18]Forschungszentrum Juelich. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. M. Lübben, F. Cüppers, J. Mohr, M. von Witzleben, U. Breuer, R.
Waser, C. Neumann, I. Valov. Design of defect-chemical properties
and device performance in memristive systems. Science Advances,
2020; 6 (19): eaaz9079 DOI: [19]10.1126/sciadv.aaz9079
__________________________________________________________________

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Date:
May 11, 2020

Source:
Helmholtz-Zentrum Berlin für Materialien und Energie

Summary:
Quantum spin liquids are candidates for potential use in future
information technologies. So far, quantum spin liquids have
usually only been found in one or two dimensional magnetic
systems only. Now an international team has investigated
crystals of PbCuTe2O6 with neutron experiments.

FULL STORY
__________________________________________________________________

They found spin liquid behaviour in 3D, due to a so called hyper
hyperkagome lattice. The experimental data fit extremely well to
theoretical simulations also done at HZB.

IT devices today are based on electronic processes in semiconductors.
The next real breakthrough could be to exploit other quantum phenomena,
for example interactions between tiny magnetic moments in the material,
the so-called spins. So-called quantum-spin liquid materials could be
candidates for such new technologies. They differ significantly from
conventional magnetic materials because quantum fluctuations dominate
the magnetic interactions: Due to geometric constraints in the crystal
lattice, spins cannot all "freeze" together in a ground state -- they
are forced to fluctuate, even at temperatures close to absolute zero.

Quantum spin liquids: a rare phenomenon

Quantum spin liquids are rare and have so far been found mainly in
two-dimensional magnetic systems. Three-dimensional isotropic spin
liquids are mostly sought in materials where the magnetic ions form
pyrochlore or hyperkagome lattices. An international team led by HZB
physicist Prof. Bella Lake has now investigated samples of PbCuTe2O6,
which has a three-dimensional lattice called hyper-hyperkagome lattice.

Magnetic interactions simulated

HZB physicist Prof. Johannes Reuther calculated the behaviour of such a
three-dimensional hyper-hyperkagome lattice with four magnetic
interactions and showed that the system exhibits quantum-spin liquid
behaviour with a specific magnetic energy spectrum.

Experiments at neutron sources find 3D quantum spin liquid

With neutron experiments at ISIS, UK, ILL, France and NIST, USA the
team was able to prove the very subtle signals of this predicted
behaviour. "We were surprised how well our data fit into the
calculations. This gives us hope that we can really understand what
happens in these systems," explains first author Dr. Shravani Chillal,
HZB.
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Story Source:

[17]Materials provided by [18]Helmholtz-Zentrum Berlin für Materialien
und Energie. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Shravani Chillal, Yasir Iqbal, Harald O. Jeschke, Jose A.
Rodriguez-Rivera, Robert Bewley, Pascal Manuel, Dmitry Khalyavin,
Paul Steffens, Ronny Thomale, A. T. M. Nazmul Islam, Johannes
Reuther, Bella Lake. Evidence for a three-dimensional quantum spin
liquid in PbCuTe2O6. Nature Communications, 2020; 11 (1) DOI:
[19]10.1038/s41467-020-15594-1
__________________________________________________________________

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resources

Date:
May 11, 2020

Source:
CNRS

Summary:
In the past few weeks, oil prices have fallen to record lows.
This development was not predicted by the Hotelling rule, an
equation proposed in 1931 that remains central to the economics
of natural resources today. Economists present the results of a
groundbreaking historical survey of documents from Harold
Hotelling's archives. They show that in fact this 'rule' was not
designed to investigate energy markets.

FULL STORY
__________________________________________________________________

In an article written in 1931, the American economist and mathematician
Harold Hotelling published a model to describe the evolution of the
prices of non-renewable resources. Following the 1973 oil crisis, the
model aroused fresh interest: the growth theorist Robert Solow named
the initial equation in this article 'the Hotelling rule', establishing
it as a fundamental principle of the economics of non-renewable
resources. However, the prices observed over the past century have
never been in line with this equation*, something which has constantly
puzzled economists.

Despite everything, the Hotelling rule still retains its central status
in the economics of mineral and energy resources: it is on this basis
that more sophisticated 'extensions' are constructed to account for
market realities. Roberto Ferreira da Cunha, from the Berkeley Research
Group (Brazil), and Antoine Missemer, a CNRS researcher attached to
CIRED, the International Centre for Research on Environment and
Development (CNRS/CIRAD/AgroParisTech/Ecole des Ponts ParisTech/EHESS),
undertook a detailed and unprecedented examination of Harold
Hotelling's archives**. By analysing the origins of the model, they
conclude that its scope of validity is more limited t han commonly
established, and decisively clarify the reasons for its empirical
weaknesses.

Hotelling's drafts, as well as his correspondence, with oil engineers
for example, point to a reinterpretation of the 1931 article. It turns
out that the 'rule', which he had devised as early as 1924 for abstract
assets, was in no way intended to be applied to the concrete case of
mineral and energy resources. From 1925 to 1930, Hotelling himself
identified unavoidable geological constraints that changed his initial
result: increased production costs as extraction progresses, or the
cost resulting from ramped up production. As he outlined, this
transformed his model, which was then potentially able to describe
bell-shaped production paths, such as those used in debates about peak
oil.

The two researchers thus show that, if the Hotelling rule has such
difficulty in passing the hurdle of empirical tests in the field of
energy and mineral resources, it is because it was not designed for
that! They propose to reconstruct the models used in this area, taking
as a starting point an alternative Hotelling rule that is more in line
with geological realities. More generally, their study questions the
theoretical instruments used to address energy and environmental issues
today. History, and in this case the history of economic thought, can
help to take a fresh look at tools that, although considered well
established, still deserve to be questioned.

This work was carried out as part of the project Bifurcations in
Natural Resource Economics (1920s-1930s), funded by the European
Society for the History of Economic Thought (ESHET).

*- The equation states that, in a competitive situation, the price of
such resources increases over time at the interest rate observed in the
economy.

**- Thousands of pages, contained in 58 archive boxes, stored at
Columbia University, New York. 20 to 30 documents taken from various
files were identified and then used by the two researchers for their
analysis.
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Story Source:

[17]Materials provided by [18]CNRS. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. Roberto Ferreira da Cunha, Antoine Missemer. The Hotelling rule in
non‐renewable resource economics: A reassessment. Canadian Journal
of Economics/Revue canadienne d'économique, 2020; DOI:
[19]10.1111/caje.12444
__________________________________________________________________

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Date:
May 11, 2020

Source:
Springer

Summary:
Scientists have developed a mathematical model of the flow of
ultra-cold superfluids, showing how they deform when they
encounter impurities.

FULL STORY
__________________________________________________________________

Superfluids, which form only at temperatures close to absolute zero,
have unique and in some ways bizarre mechanical properties, Yvan Buggy
of the Institute of Photonics and Quantum Sciences at Heriot-Watt
University in Edinburgh, Scotland, and his co-workers have developed a
new quantum mechanical model of some of these properties, which
illustrates how these fluids will deform as they flow around
impurities. This work is published in the journal EPJ D.

Imagine that you start stirring a cup of tea, come back to it five
minutes later and find that the tea is still circulating. In itself,
this is clearly impossible, but if you could stir a cup of an
ultra-cold liquid this is exactly what would happen. Below about -270oC
-- that is, just a few degrees above the coldest possible temperature,
absolute zero -- the liquid becomes a superfluid: a weird substance
that has no viscosity and that therefore will flow without losing
kinetic energy, creep along surfaces and along vessel walls, and
continue to spin indefinitely around vertices.

Superfluids acquire these properties because so many of their atoms
fall into the lowest energy state that quantum mechanical properties
dominate over classical ones. They therefore provide a unique
opportunity for studying quantum phenomena on a macroscopic level, if
in extreme conditions. In this study, Buggy and his colleagues use the
essential equations of quantum mechanics to calculate the stresses and
flows in such an ultracold superfluid under changes in potential
energy. They show that the fluid flow will be steady and homogeneous in
the absence of impurities. If an impurity is present, however, the
fluid will become deformed in the vicinity of that impurity.
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Story Source:

[17]Materials provided by [18]Springer. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. Yvan Buggy, Lawrence G. Phillips, Patrik Öhberg. On the
hydrodynamics of nonlinear gauge-coupled quantum fluids. The
European Physical Journal D, 2020; 74 (5) DOI:
[19]10.1140/epjd/e2020-100524-3
__________________________________________________________________

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Date:
May 11, 2020

Source:
Arizona State University

Summary:
Researchers investigated how solar reflective coatings on select
Los Angeles city streets affected radiant heat and, in turn,
pedestrians' comfort on a typical summer day. The idea is, if
you coat a street with a lighter color than traditional pavement
black, it will actually lower the surrounding temperatures. But
researchers wanted to measure what effect reflective coating had
on pedestrians.

FULL STORY
__________________________________________________________________

One day last July, Ariane Middel and two other Arizona State University
researchers headed west on Interstate 10. Squeezed inside their van
were MaRTy 1 and MaRTy 2, mobile biometeorological instrument platforms
that can tell you exactly what you feel in the summer heat. All five
were destined for Los Angeles.

The researchers and their colleagues were headed to L.A. to start
investigating how solar reflective coatings on select city streets
affected radiant heat and, in turn, pedestrians' comfort on a typical
summer day.

The Los Angeles Bureau of Street Surfaces has pioneered the use of
solar reflective coatings in a quest to cool city streets.

The idea is, if you coat a street with a lighter color than traditional
pavement black, it will actually lower the surrounding temperatures.

But Middel and her collaborators now wanted to see what effect
reflective coating had on pedestrians.

"If you're in a hot, dry and sunny climate like Phoenix or L.A., the
mean radiant temperature has the biggest impact on how a person
experiences the heat," explains Middel, assistant professor in the ASU
School of Arts, Media and Engineering and a senior sustainability
scientist in the Julie Ann Wrigley Global Institute of Sustainability.
"The mean radiant temperature is essentially the heat that hits the
human body. It includes the radiation from the sun, so if you are
standing in direct sunlight you will feel much hotter than in the
shade."

Thanks to remote-sensing satellites, decades of data exist on the
Earth's land surface temperature; that is, how hot a single point on
the Earth's surface would feel to the touch. But that data should not
be confused with near-surface ambient and radiant temperature, the heat
that humans and animals "experience," said Middel, lead author of the
study and director of ASU's SHaDE Lab, which stands for Sensable
Heatscapes and Digital Environments.

The researchers' study is the first to measure the thermal performance
of solar reflective coatings using instruments that sense
meteorological variables relevant to a pedestrian's experience: radiant
heat, ambient temperature, wind and humidity.

The researchers focused on two variables, surface temperature and
radiant temperature over highly reflective surfaces. They took MaRTy 1
and 2 on hourly strolls through a Los Angeles neighborhood to measure a
pedestrian's heat exposure over regular asphalt roads, reflective
coated roads and sidewalks next to the roads.

MaRTy, which stands for mean radiant temperature, looks like a weather
station in a wagon. The station measures the total radiation that hits
the body, including sunlight and the heat emitted from surfaces like
asphalt.

The study showed that the surface temperature of the coated asphalt
road was up to 6 degrees Celsius cooler than the regular road in the
afternoon. However, the radiant heat over coated asphalt was 4 degrees
Celsius higher than non-coated areas, basically negating any
heat-limiting factor.

"So, if you're a pedestrian walking over the surface, you get hit by
the shortwave radiation reflected back at you," Middel said.

The study also found that the coating didn't have a big impact on air
temperature, only half a degree in the afternoon and 0.1 degrees
Celsius at night.

The upshot, said V. Kelly Turner, assistant professor of urban planning
at UCLA and the study's co-author, is that to cool off cities, urban
climatologists and city planners need to focus on different solutions
or combinations of solutions depending on a desired goal.

"The solutions are context dependent and depend on what you want to
achieve," Turner explained.

A solution that addresses surface temperature is not necessarily suited
to the reduction of building energy use. For example, if you want
cooler surface temperatures on a playground because children are
running across its surface, a reflective coating would be best. But if
you want to reduce the thermal load on people, planting trees or
providing shade would be more effective.

But what happens if you combine trees with cool pavement? Does the cool
pavement lose its ability to reduce surface temperature? Or perhaps the
cool pavement is costly to maintain when the trees drop their leaves?

"So, reflective coating is not a panacea," Turner said. "It's one
tool."

It should also be noted that temperature is a multifaceted measurement
of heat. Surface temperature, ambient temperature and mean radiant
temperature are distinct from one another and require distinct
solutions when it comes to mitigating heat.

"We need more of these experiments," Middel said. "There have been a
lot of large-scale modeling studies on this. So, we don't know in real
life if we get the same effects. The urban environment is so complex,
and models have to always simplify. So, we don't know what really
happens on the ground unless we measure, and there haven't been these
types of measurements in the past."

The researchers report their findings of the Los Angeles study in,
"Solar reflective pavements -- A policy panacea to heat mitigation?"
which was published on April 8, 2020 in the journal Environmental
Research Letters. Co-authors on the paper include Florian Schneider and
Yujia Zhang of ASU, and Matthew Stiller of Kent State University.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Arizona State University. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Ariane Middel, V. Kelly Turner, Florian Arwed Schneider, Yujia
Zhang, Matthew Stiller. Solar reflective pavements – a policy
panacea to heat mitigation? Environmental Research Letters, 2020;
DOI: [19]10.1088/1748-9326/ab87d4
__________________________________________________________________

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Date:
May 11, 2020

Source:
North Carolina State University

Summary:
A new study suggests that a polymer compound embedded with
bismuth trioxide particles holds tremendous potential for
replacing conventional radiation shielding materials, such as
lead.

FULL STORY
__________________________________________________________________

A new study from researchers at North Carolina State University
suggests that a material consisting of a polymer compound embedded with
bismuth trioxide particles holds tremendous potential for replacing
conventional radiation shielding materials, such as lead.

The bismuth trioxide compound is lightweight, effective at shielding
against ionizing radiation such as gamma rays, and can be manufactured
quickly -- making it a promising material for use in applications such
as space exploration, medical imaging and radiation therapy.

"Traditional radiation shielding materials, like lead, are often
expensive, heavy and toxic to human health and the environment," says
Ge Yang, an assistant professor of nuclear engineering at NC State and
corresponding author of a paper on the work. "This proof-of-concept
study shows that a bismuth trioxide compound could serve as effective
radiation shielding, while mitigating the drawbacks associated with
traditional shielding materials."

In the new study, researchers demonstrated that they could create the
compound using a curing method that relies on ultraviolet (UV) light --
rather than relying on time-consuming high-temperature techniques.

"Using the UV curing method, we were able to create the compound on the
order of minutes at room temperature -- which holds potential for the
rapid manufacturing of radiation shielding materials," Yang says. "This
is an important point because thermal polymerization, a frequently used
method for making polymer compounds, often relies on high temperatures
and can take hours or even days to complete. The UV curing method is
both faster and less expensive."

Using the UV curing method, the researchers created samples of the
polymer compound that include as much as 44% bismuth trioxide by
weight. The researchers then tested the samples to determine the
material's mechanical properties and whether it could effectively
shield against ionizing radiation.

"This is foundational work," Yang says. "We have determined that the
compound is effective at shielding gamma rays, is lightweight and is
strong. We are working to further optimize this technique to get the
best performance from the material.

"We are excited about finding a novel radiation shielding material that
works this well, is this light, and can be manufactured this quickly."
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Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Da Cao, Ge Yang, Mohamed Bourham, Dan Moneghan. Gamma radiation
shielding properties of poly (methyl methacrylate) / Bi2O3
composites. Nuclear Engineering and Technology, 2020; DOI:
[19]10.1016/j.net.2020.04.026
__________________________________________________________________

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Date:
May 11, 2020

Source:
University of Alaska Fairbanks

Summary:
A research team has developed a way to use satellite images to
determine the amount of methane being released from northern
lakes, a technique that could help climate change modelers
better account for this potent greenhouse gas. By using
synthetic aperture radar, or SAR, researchers were able to find
a correlation between 'brighter' satellite images of frozen
lakes and the amount of methane they produce.

FULL STORY
__________________________________________________________________

A University of Alaska Fairbanks-led research team has developed a way
to use satellite images to determine the amount of methane being
released from northern lakes, a technique that could help climate
change modelers better account for this potent greenhouse gas.

By using synthetic aperture radar, or SAR, researchers were able to
find a correlation between "brighter" satellite images of frozen lakes
and the amount of methane they produce. Comparing those SAR images with
ground-level methane measurements confirmed that the satellite readings
were consistent with on-site data.

SAR data, which were provided by UAF's Alaska Satellite Facility, are
well-suited to the Arctic. The technology can penetrate dry snow, and
doesn't require daylight or cloud-free conditions. SAR is also good at
imaging frozen lakes, particularly ones filled with bubbles that often
form in ice when methane is present.

"We found that backscatter is brighter when there are more bubbles
trapped in the lake ice," said Melanie Engram, the lead author of the
study and a researcher at UAF's Water and Environmental Research
Center. "Bubbles form an insulated blanket, so ice beneath them grows
more slowly, causing a warped surface which reflects the radar signal
back to the satellite."

The new technique could have significant implications for climate
change predictions. Methane is about 30 times more powerful than carbon
dioxide as a heat-trapping gas, so accurate estimates about its
prevalence are particularly important in scientific models.

Previous research had confirmed that vast amounts of methane are being
released from thermokarst lakes as the permafrost beneath them thaws.
But collecting on-site data from those lakes is often expensive and
logistically challenging. Because of that, information about methane
production is available from only a tiny percentage of Arctic lakes.

"This new technique is a major breakthrough for understanding the
Arctic methane budget," said UAF researcher Katey Walter Anthony, who
also contributed to the study. "It helps to resolve a longstanding
discrepancy between estimates of Arctic methane emissions from
atmospheric measurements and data upscaled from a small number of
individual lakes."

To confirm the SAR data, researchers compared satellite images with
field measurements from 48 lakes in five geographic areas in Alaska. By
extrapolating those results, researchers can now estimate the methane
production of more than 5,000 Alaska lakes.

"It's important to know how much methane comes out of these lakes and
whether the level is increasing," Engram said. "We can't get out to
every single lake and do field work, but we can extrapolate field
measurements using SAR remote sensing to get these regional estimates."
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Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. M. Engram, K. M. Walter Anthony, T. Sachs, K. Kohnert, A.
Serafimovich, G. Grosse, F. J. Meyer. Remote sensing northern lake
methane ebullition. Nature Climate Change, 2020; DOI:
[19]10.1038/s41558-020-0762-8
__________________________________________________________________

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Date:
May 11, 2020

Source:
International Institute for Applied Systems Analysis

Summary:
A new study investigated the impacts of different levels of
global warming on hydropower potential and found that this type
of electricity generation benefits more from a 1.5°C than a 2°C
climate scenario.

FULL STORY
__________________________________________________________________

A new study by researchers from IIASA and China investigated the
impacts of different levels of global warming on hydropower potential
and found that this type of electricity generation benefits more from a
1.5°C than a 2°C climate scenario.

In a sustainable and less carbon-intensive future, hydropower will play
an increasingly crucial role as an important source of renewable and
clean energy in the world's overall energy supply. In fact, hydropower
generation has doubled over the last three decades and is projected to
double again from the present level by 2050. Global warming is however
threatening the world's water supplies, posing a significant threat to
hydropower generation, which is a problem in light of the continuous
increase in energy demand due to global population growth and
socioeconomic development.

The study, undertaken by researchers from IIASA in collaboration with
colleagues at several Chinese institutions and published in the journal
Water Resources Research, employed a coupled hydrological and
techno-economic model framework to identify optimal locations for
hydropower plants under global warming levels of 1.5°C and 2°C, while
also considering gross hydropower potential, power consumption, and
economic factors. According to the authors, while determining the
effects of different levels of global warming has become a hot topic in
water resources research, there are still relatively few studies on the
impacts of different global warming levels on hydropower potential.

The researchers specifically looked at the potential for hydropower
production under the two different levels of warming in Sumatra, one of
the Sunda Islands of western Indonesia. Sumatra was chosen as it is
vulnerable to global warming because of sea level rise, and the
island's environmental conditions make it an ideal location for
developing and utilizing hydropower resources. They also modeled and
visualized optimal locations of hydropower plants using the IIASA
BeWhere model, and discussed hydropower production based on selected
hydropower plants and the reduction in carbon emissions that would
result from using hydropower instead of fossil fuels.

The results show that global warming levels of both 1.5°C and 2°C will
have a positive impact on the hydropower production of Sumatra relative
to the historical period. The ratio of hydropower production to power
demand provided by 1.5°C of global warming is however greater than that
provided by 2°C of global warming under a scenario that assumes
stabilization without overshooting the target after 2100. This is due
to a decrease in precipitation and the fact that the south east of
Indonesia observes the highest discharge decrease under this scenario.
In addition, the reduction in CO2 emissions under global warming of
1.5°C is greater than that achieved under global warming of 2°C, which
reveals that global warming decreases the benefits necessary to relieve
global warming levels. The findings also illustrate the tension between
greenhouse gas-related goals and ecosystem conservation-related goals
by considering the trade-off between the protected areas and hydropower
plant expansion.

"Our study could significantly contribute to establishing a basis for
decision making on energy security under 1.5°C and 2°C global warming
scenarios. Our findings can also potentially be an important basis for
a large range of follow-up studies to, for instance, investigate the
trade-off between forest conservancy and hydropower development, to
contribute to the achievement of countries' Nationally Determined
Contributions under the Paris Agreement," concludes study lead author
Ying Meng, who started work on this project as a participant of the
2018 IIASA Young Scientists Summer Program (YSSP). She is currently
affiliated with the School of Environment at the Harbin Institute of
Technology in China.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]International Institute for Applied
Systems Analysis. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Ying Meng, Junguo Liu, Sylvain Leduc, Sennai Mesfun, Florian
Kraxner, Ganquan Mao, Wei Qi, Zifeng Wang. Hydropower Production
Benefits More From 1.5 °C than 2 °C Climate Scenario. Water
Resources Research, 2020; 56 (5) DOI: [19]10.1029/2019WR025519
__________________________________________________________________

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Linking multiple copies of these devices may lay the foundation for quantum computing

Date:
May 11, 2020

Source:
National Institute of Standards and Technology (NIST)

Summary:
Researchers have developed a step-by-step recipe to produce
single-atom transistors.

FULL STORY
__________________________________________________________________

Once unimaginable, transistors consisting only of several-atom clusters
or even single atoms promise to become the building blocks of a new
generation of computers with unparalleled memory and processing power.
But to realize the full potential of these tiny transistors --
miniature electrical on-off switches -- researchers must find a way to
make many copies of these notoriously difficult-to-fabricate
components.

Now, researchers at the National Institute of Standards and Technology
(NIST) and their colleagues at the University of Maryland have
developed a step-by-step recipe to produce the atomic-scale devices.
Using these instructions, the NIST-led team has become only the second
in the world to construct a single-atom transistor and the first to
fabricate a series of single electron transistors with atom-scale
control over the devices' geometry.

The scientists demonstrated that they could precisely adjust the rate
at which individual electrons flow through a physical gap or electrical
barrier in their transistor -- even though classical physics would
forbid the electrons from doing so because they lack enough energy.
That strictly quantum phenomenon, known as quantum tunneling, only
becomes important when gaps are extremely tiny, such as in the
miniature transistors. Precise control over quantum tunneling is key
because it enables the transistors to become "entangled" or interlinked
in a way only possible through quantum mechanics and opens new
possibilities for creating quantum bits (qubits) that could be used in
quantum computing.

To fabricate single-atom and few-atom transistors, the team relied on a
known technique in which a silicon chip is covered with a layer of
hydrogen atoms, which readily bind to silicon. The fine tip of a
scanning tunneling microscope then removed hydrogen atoms at selected
sites. The remaining hydrogen acted as a barrier so that when the team
directed phosphine gas (PH[3]) at the silicon surface, individual PH[3]
molecules attached only to the locations where the hydrogen had been
removed (see animation). The researchers then heated the silicon
surface. The heat ejected hydrogen atoms from the PH[3] and caused the
phosphorus atom that was left behind to embed itself in the surface.
With additional processing, bound phosphorus atoms created the
foundation of a series of highly stable single- or few-atom devices
that have the potential to serve as qubits.

Two of the steps in the method devised by the NIST teams -- sealing the
phosphorus atoms with protective layers of silicon and then making
electrical contact with the embedded atoms -- appear to have been
essential to reliably fabricate many copies of atomically precise
devices, NIST researcher Richard Silver said.

In the past, researchers have typically applied heat as all the silicon
layers are grown, in order to remove defects and ensure that the
silicon has the pure crystalline structure required to integrate the
single-atom devices with conventional silicon-chip electrical
components. But the NIST scientists found that such heating could
dislodge the bound phosphorus atoms and potentially disrupt the
structure of the atomic-scale devices. Instead, the team deposited the
first several silicon layers at room temperature, allowing the
phosphorus atoms to stay put. Only when subsequent layers were
deposited did the team apply heat.

"We believe our method of applying the layers provides more stable and
precise atomic-scale devices," said Silver. Having even a single atom
out of place can alter the conductivity and other properties of
electrical components that feature single or small clusters of atoms.

The team also developed a novel technique for the crucial step of
making electrical contact with the buried atoms so that they can
operate as part of a circuit. The NIST scientists gently heated a layer
of palladium metal applied to specific regions on the silicon surface
that resided directly above selected components of the silicon-embedded
device. The heated palladium reacted with the silicon to form an
electrically conducting alloy called palladium silicide, which
naturally penetrated through the silicon and made contact with the
phosphorus atoms.

In a recent edition of Advanced Functional Materials, Silver and his
colleagues, who include Xiqiao Wang, Jonathan Wyrick, Michael Stewart
Jr. and Curt Richter, emphasized that their contact method has a nearly
100% success rate. That's a key achievement, noted Wyrick. "You can
have the best single-atom-transistor device in the world, but if you
can't make contact with it, it's useless," he said.

Fabricating single-atom transistors "is a difficult and complicated
process that maybe everyone has to cut their teeth on, but we've laid
out the steps so that other teams don't have to proceed by trial and
error," said Richter.

In related work published today in Communications Physics, Silver and
his colleagues demonstrated that they could precisely control the rate
at which individual electrons tunnel through atomically precise tunnel
barriers in single-electron transistors. The NIST researchers and their
colleagues fabricated a series of single-electron transistors identical
in every way except for differences in the size of the tunneling gap.
Measurements of current flow indicated that by increasing or decreasing
the gap between transistor components by less than a nanometer
(billionth of a meter), the team could precisely control the flow of a
single electron through the transistor in a predictable manner.

"Because quantum tunneling is so fundamental to any quantum device,
including the construction of qubits, the ability to control the flow
of one electron at a time is a significant achievement," Wyrick said.
In addition, as engineers pack more and more circuitry on a tiny
computer chip and the gap between components continues to shrink,
understanding and controlling the effects of quantum tunneling will
become even more critical, Richter said.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]National Institute of Standards and
Technology (NIST). Note: Content may be edited for style and length.
__________________________________________________________________

Journal References:
1. Xiqiao Wang, Jonathan Wyrick, Ranjit V. Kashid, Pradeep Namboodiri,
Scott W. Schmucker, Andrew Murphy, M. D. Stewart, Richard M.
Silver. Atomic-scale control of tunneling in donor-based devices.
Communications Physics, 2020; 3 (1) DOI:
[19]10.1038/s42005-020-0343-1
2. Jonathan Wyrick, Xiqiao Wang, Ranjit V. Kashid, Pradeep Namboodiri,
Scott W. Schmucker, Joseph A. Hagmann, Keyi Liu, Michael D.
Stewart, Curt A. Richter, Garnett W. Bryant, Richard M. Silver.
Atom‐by‐Atom Fabrication of Single and Few Dopant Quantum Devices.
Advanced Functional Materials, 2019; 29 (52): 1903475 DOI:
[20]10.1002/adfm.201903475
__________________________________________________________________

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data

Date:
May 12, 2020

Source:
University of California - Santa Cruz

Summary:
Researchers have developed a powerful new computer program
called Morpheus that can analyze astronomical image data pixel
by pixel to identify and classify all of the galaxies and stars
in large data sets from astronomy surveys. Morpheus is a
deep-learning framework that incorporates a variety of
artificial intelligence technologies developed for applications
such as image and speech recognition.

FULL STORY
__________________________________________________________________

Researchers at UC Santa Cruz have developed a powerful new computer
program called Morpheus that can analyze astronomical image data pixel
by pixel to identify and classify all of the galaxies and stars in
large data sets from astronomy surveys.

Morpheus is a deep-learning framework that incorporates a variety of
artificial intelligence technologies developed for applications such as
image and speech recognition. Brant Robertson, a professor of astronomy
and astrophysics who leads the Computational Astrophysics Research
Group at UC Santa Cruz, said the rapidly increasing size of astronomy
data sets has made it essential to automate some of the tasks
traditionally done by astronomers.

"There are some things we simply cannot do as humans, so we have to
find ways to use computers to deal with the huge amount of data that
will be coming in over the next few years from large astronomical
survey projects," he said.

Robertson worked with Ryan Hausen, a computer science graduate student
in UCSC's Baskin School of Engineering, who developed and tested
Morpheus over the past two years. With the publication of their results
May 12 in the Astrophysical Journal Supplement Series, Hausen and
Robertson are also releasing the Morpheus code publicly and providing
online demonstrations.

The morphologies of galaxies, from rotating disk galaxies like our own
Milky Way to amorphous elliptical and spheroidal galaxies, can tell
astronomers about how galaxies form and evolve over time. Large-scale
surveys, such as the Legacy Survey of Space and Time (LSST) to be
conducted at the Vera Rubin Observatory now under construction in
Chile, will generate huge amounts of image data, and Robertson has been
involved in planning how to use that data to understand the formation
and evolution of galaxies. LSST will take more than 800 panoramic
images each night with a 3.2-billion-pixel camera, recording the entire
visible sky twice each week.

"Imagine if you went to astronomers and asked them to classify billions
of objects -- how could they possibly do that? Now we'll be able to
automatically classify those objects and use that information to learn
about galaxy evolution," Robertson said.

Other astronomers have used deep-learning technology to classify
galaxies, but previous efforts have typically involved adapting
existing image recognition algorithms, and researchers have fed the
algorithms curated images of galaxies to be classified. Hausen built
Morpheus from the ground up specifically for astronomical image data,
and the model uses as input the original image data in the standard
digital file format used by astronomers.

Pixel-level classification is another important advantage of Morpheus,
Robertson said. "With other models, you have to know something is there
and feed the model an image, and it classifies the entire galaxy at
once," he said. "Morpheus discovers the galaxies for you, and does it
pixel by pixel, so it can handle very complicated images, where you
might have a spheroidal right next to a disk. For a disk with a central
bulge, it classifies the bulge separately. So it's very powerful."

To train the deep-learning algorithm, the researchers used information
from a 2015 study in which dozens of astronomers classified about
10,000 galaxies in Hubble Space Telescope images from the CANDELS
survey. They then applied Morpheus to image data from the Hubble Legacy
Fields, which combines observations taken by several Hubble deep-field
surveys.

When Morpheus processes an image of an area of the sky, it generates a
new set of images of that part of the sky in which all objects are
color-coded based on their morphology, separating astronomical objects
from the background and identifying point sources (stars) and different
types of galaxies. The output includes a confidence level for each
classification. Running on UCSC's lux supercomputer, the program
rapidly generates a pixel-by-pixel analysis for the entire data set.

"Morpheus provides detection and morphological classification of
astronomical objects at a level of granularity that doesn't currently
exist," Hausen said.

An interactive visualization of the Morpheus model results for GOODS
South, a deep-field survey that imaged millions of galaxies, has been
publicly released. This work was supported by NASA and the National
Science Foundation.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of California - Santa Cruz.
Original written by Tim Stephens. Note: Content may be edited for style
and length.
__________________________________________________________________

Journal Reference:
1. Ryan Hausen, Brant E. Robertson. Morpheus: A Deep Learning
Framework for the Pixel-level Analysis of Astronomical Image Data.
The Astrophysical Journal Supplement Series, 2020; 248 (1): 20 DOI:
[19]10.3847/1538-4365/ab8868
__________________________________________________________________

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Date:
May 12, 2020

Source:
University of Cambridge

Summary:
Machine learning and AI are highly unstable in medical image
reconstruction, and may lead to false positives and false
negatives, a new study suggests.

FULL STORY
__________________________________________________________________

Machine learning and AI are highly unstable in medical image
reconstruction, and may lead to false positives and false negatives, a
new study suggests.

A team of researchers, led by the University of Cambridge and Simon
Fraser University, designed a series of tests for medical image
reconstruction algorithms based on AI and deep learning, and found that
these techniques result in myriad artefacts, or unwanted alterations in
the data, among other major errors in the final images. The effects
were typically not present in non-AI based imaging techniques.

The phenomenon was widespread across different types of artificial
neural networks, suggesting that the problem will not be easily
remedied. The researchers caution that relying on AI-based image
reconstruction techniques to make diagnoses and determine treatment
could ultimately do harm to patients. Their results are reported in the
Proceedings of the National Academy of Sciences.

"There's been a lot of enthusiasm about AI in medical imaging, and it
may well have the potential to revolutionise modern medicine: however,
there are potential pitfalls that must not be ignored," said Dr Anders
Hansen from Cambridge's Department of Applied Mathematics and
Theoretical Physics, who led the research with Dr Ben Adcock from Simon
Fraser University. "We've found that AI techniques are highly unstable
in medical imaging, so that small changes in the input may result in
big changes in the output."

A typical MRI scan can take anywhere between 15 minutes and two hours,
depending on the size of the area being scanned and the number of
images being taken. The longer the patient spends inside the machine,
the higher resolution the final image will be. However, limiting the
amount of time patients spend inside the machine is desired, both to
reduce the risk to individual patients and to increase the overall
number of scans that can be performed.

Using AI techniques to improve the quality of images from MRI scans or
other types of medical imaging is an attractive possibility for solving
the problem of getting the highest quality image in the smallest amount
of time: in theory, AI could take a low-resolution image and make it
into a high-resolution version. AI algorithms 'learn' to reconstruct
images based on training from previous data, and through this training
procedure aim to optimise the quality of the reconstruction. This
represents a radical change compared to classical reconstruction
techniques that are solely based on mathematical theory without
dependency on previous data. In particular, classical techniques do not
learn.

Any AI algorithm needs two things to be reliable: accuracy and
stability. An AI will usually classify an image of a cat as a cat, but
tiny, almost invisible changes in the image might cause the algorithm
to instead classify the cat as a truck or a table, for instance. In
this example of image classification, the one thing that can go wrong
is that the image is incorrectly classified. However, when it comes to
image reconstruction, such as that used in medical imaging, there are
several things that can go wrong. For example, details like a tumour
may get lost or may falsely be added. Details can be obscured and
unwanted artefacts may occur in the image.

"When it comes to critical decisions around human health, we can't
afford to have algorithms making mistakes," said Hansen. "We found that
the tiniest corruption, such as may be caused by a patient moving, can
give a very different result if you're using AI and deep learning to
reconstruct medical images -- meaning that these algorithms lack the
stability they need."

Hansen and his colleagues from Norway, Portugal, Canada and the UK
designed a series of tests to find the flaws in AI-based medical
imaging systems, including MRI, CT and NMR. They considered three
crucial issues: instabilities associated with tiny perturbations, or
movements; instabilities with respect to small structural changes, such
as a brain image with or without a small tumour; and instabilities with
respect to changes in the number of samples.

They found that certain tiny movements led to myriad artefacts in the
final images, details were blurred or completely removed, and that the
quality of image reconstruction would deteriorate with repeated
subsampling. These errors were widespread across the different types of
neural networks.

According to the researchers, the most worrying errors are the ones
that radiologists might interpret as medical issues, as opposed to
those that can easily be dismissed due to a technical error.

"We developed the test to verify our thesis that deep learning
techniques would be universally unstable in medical imaging," said
Hansen. "The reasoning for our prediction was that there is a limit to
how good a reconstruction can be given restricted scan time. In some
sense, modern AI techniques break this barrier, and as a result become
unstable. We've shown mathematically that there is a price to pay for
these instabilities, or to put it simply: there is still no such thing
as a free lunch."

The researchers are now focusing on providing the fundamental limits to
what can be done with AI techniques. Only when these limits are known
will we be able to understand which problems can be solved. "Trial and
error-based research would never discover that the alchemists could not
make gold: we are in a similar situation with modern AI," said Hansen.
"These techniques will never discover their own limitations. Such
limitations can only be shown mathematically."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Cambridge. The original
story is licensed under a [19]Creative Commons License. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Vegard Antun, Francesco Renna, Clarice Poon, Ben Adcock, Anders C.
Hansen. On instabilities of deep learning in image reconstruction
and the potential costs of AI. Proceedings of the National Academy
of Sciences, 2020; 201907377 DOI: [20]10.1073/pnas.1907377117
__________________________________________________________________

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Date:
May 12, 2020

Source:
eLife

Summary:
A new tool using cutting-edge technology is able to distinguish
different types of blood clots based on what caused them,
according to a new study.

FULL STORY
__________________________________________________________________

A new tool using cutting-edge technology is able to distinguish
different types of blood clots based on what caused them, according to
a study published in eLife.

The tool could help physicians diagnose what caused a blood clot and
help them select a treatment that targets cause to break it up. For
example, it could help them determine if aspirin or another kind of
anti-clotting drug would be the best choice for a person who has just
had a heart attack or stroke.

Blood clots occur when small sticky blood cells called platelets
cluster together. This can help stop bleeding after a cut, but it can
also be harmful in causing a stroke or a heart attack by blocking a
blood vessel. "Different types of blood clots are caused by different
molecules, but they all look very similar," explains lead author Yuqi
Zhou, a PhD student at the Department of Chemistry, University of
Tokyo, Japan. "What's more, they are nearly impossible to tell apart
using existing tools such as microscopes."

To develop a more effective approach to identifying different types of
blood clots, Zhou and her colleagues took blood samples from a healthy
individual and then exposed them to different clotting agents. The team
captured thousands of images of the different types of clots using a
technique called high-throughput imaging flow cytometry.

They next used a type of machine-learning technology called a
convolutional neural network to train a computer to identify subtle
differences in the shape of different types of clots caused by
different molecules. They tested this tool on 25,000 clot images that
the computer had never seen before and found it was also able to
distinguish most of the clot types in the images.

Finally, they tested whether this new tool, which they named the
intelligent platelet aggregate classifier (iPAC), can diagnose
different clot types in human blood samples. They took blood samples
from four healthy people, exposed them to different clotting agents,
and showed that iPAC could tell the different types of clots apart.

"We showed that iPAC is a powerful tool for studying the underlying
mechanism of clot formation," Zhou says. She adds that, given recent
reports that COVID-19 causes blood clots, the technology could one day
be used to better understand the mechanism behind these clots too,
although much about the virus currently remains unknown.

"Using this new tool may uncover the characteristics of different types
of clots that were previously unrecognised by humans, and enable the
diagnosis of clots caused by combinations of clotting agents," says
senior author Keisuke Goda, Professor at the Department of Chemistry,
University of Tokyo. "Information about the causes of clots can help
researchers and medical doctors evaluate the effectiveness of
anti-clotting drugs and choose the right treatment, or combination of
treatments, for a particular patient."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]eLife. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. Yuqi Zhou, Atsushi Yasumoto, Cheng Lei, Chun-Jung Huang, Hirofumi
Kobayashi, Yunzhao Wu, Sheng Yan, Chia-Wei Sun, Yutaka Yatomi,
Keisuke Goda. Intelligent classification of platelet aggregates by
agonist type. eLife, 2020; 9 DOI: [19]10.7554/eLife.52938
__________________________________________________________________

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Date:
May 12, 2020

Source:
University of Alberta

Summary:
Trained dogs can detect fire accelerants such as gasoline in
quantities as small as one billionth of a teaspoon, according to
new research by chemists. The study provides the lowest estimate
of the limit of sensitivity of dogs' noses and has implications
for arson investigations.

FULL STORY
__________________________________________________________________

Trained dogs can detect fire accelerants such as gasoline in quantities
as small as one billionth of a teaspoon, according to new research by
University of Alberta chemists. The study provides the lowest estimate
of the limit of sensitivity of dogs' noses and has implications for
arson investigations.

"During an arson investigation, a dog may be used to identify debris
that contains traces of ignitable liquids -- which could support a
hypothesis that a fire was the result of arson," explained Robin Abel,
graduate student in the Department of Chemistry and lead author of the
study. "Of course, a dog cannot give testimony in court, so debris from
where the dog indicated must be taken back to the laboratory and
analyzed. This estimate provides a target for forensic labs when
processing evidence flagged by detection dogs at sites of potential
arson."

The study involved two dog-and-handler teams. The first was trained to
detect a variety of ignitable liquids, while the other was trained
primarily with gasoline. Results show that the dog trained on a variety
of liquids performed well detecting all accelerants, while the dog
trained on gasoline was not able to generalize to other accelerants at
extremely low concentrations.

Another outcome of the study was the development of a protocol that can
be used to generate suitable ultra-clean substrates necessary for
assessing the performance of accelerant-detection dogs for trace-level
detection.

"In this field, it is well-known that dogs are more sensitive than
conventional laboratory tests," said James Harynuk, associate professor
of chemistry and Abel's supervisor. "There have been many cases where a
dog will flag debris that then tests negative in the lab. In order for
us to improve laboratory techniques so that they can match the
performance of the dogs, we must first assess the dogs. This work gives
us a very challenging target to meet for our laboratory methods."

So, just how small a volume of gasoline can a dog detect?

"The dogs in this study were able to detect down to one billionth of a
teaspoon -- or 5 pL -- of gasoline," added Harynuk. "Their noses are
incredibly sensitive."

This research was conducted in collaboration with Jeff Lunder, vice
president of the Canine Accelerant Detection Association (CADA) Fire
Dogs. Funding was provided by the Natural Sciences and Engineering
Research Council of Canada (NSERC).
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Alberta. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Robin J. Abel, Jeffrey L. Lunder, James J. Harynuk. A novel
protocol for producing low-abundance targets to characterize the
sensitivity limits of ignitable liquid detection canines. Forensic
Chemistry, 2020; 18: 100230 DOI: [19]10.1016/j.forc.2020.100230
__________________________________________________________________

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Researchers use plasmonics to enhance fluorescent markers in lab-on-a-chip diagnostic devices

Date:
May 12, 2020

Source:
Duke University

Summary:
Engineers have shown that nanosized silver cubes can make
diagnostic tests that rely on fluorescence easier to read by
making them more than 150 times brighter. Combined with an
emerging point-of-care diagnostic platform already shown to be
able to detect small traces of viruses and other biomarkers, the
approach could allow such tests to become much cheaper and more
widespread.

FULL STORY
__________________________________________________________________

Engineers at Duke University have shown that nanosized silver cubes can
make diagnostic tests that rely on fluorescence easier to read by
making them more than 150 times brighter. Combined with an emerging
point-of-care diagnostic platform already shown capable of detecting
small traces of viruses and other biomarkers, the approach could allow
such tests to become much cheaper and more widespread.

The results appeared online on May 6 in the journal Nano Letters.

Plasmonics is a scientific field that traps energy in a feedback loop
called a plasmon onto the surface of silver nanocubes. When fluorescent
molecules are sandwiched between one of these nanocubes and a metal
surface, the interaction between their electromagnetic fields causes
the molecules to emit light much more vigorously. Maiken Mikkelsen, the
James N. and Elizabeth H. Barton Associate Professor of Electrical and
Computer Engineering at Duke, has been working with her laboratory at
Duke to create new types of hyperspectral cameras and superfast optical
signals using plasmonics for nearly a decade.

At the same time, researchers in the laboratory of Ashutosh Chilkoti,
the Alan L. Kaganov Distinguished Professor of Biomedical Engineering,
have been working on a self-contained, point-of-care diagnostic test
that can pick out trace amounts of specific biomarkers from biomedical
fluids such as blood. But because the tests rely on fluorescent markers
to indicate the presence of the biomarkers, seeing the faint light of a
barely positive test requires expensive and bulky equipment.

"Our research has already shown that plasmonics can enhance the
brightness of fluorescent molecules tens of thousands of times over,"
said Mikkelsen. "Using it to enhance diagnostic assays that are limited
by their fluorescence was clearly a very exciting idea."

"There are not a lot of examples of people using plasmon-enhanced
fluorescence for point-of-care diagnostics, and the few that exist have
not been yet implemented into clinical practice," added Daria Semeniak,
a graduate student in Chilkoti's laboratory. "It's taken us a couple of
years, but we think we've developed a system that can work."

In the new paper, researchers from the Chilkoti lab build their
super-sensitive diagnostic platform called the D4 Assay onto a thin
film of gold, the preferred yin to the plasmonic silver nanocube's
yang. The platform starts with a thin layer of polymer brush coating,
which stops anything from sticking to the gold surface that the
researchers don't want to stick there. The researchers then use an
ink-jet printer to attach two groups of molecules tailored to latch on
to the biomarker that the test is trying to detect. One set is attached
permanently to the gold surface and catches one part of the biomarker.
The other is washed off of the surface once the test begins, attaches
itself to another piece of the biomarker, and flashes light to indicate
it's found its target.

After several minutes pass to allow the reactions to occur, the rest of
the sample is washed away, leaving behind only the molecules that have
managed to find their biomarker matches, floating like fluorescent
beacons tethered to a golden floor.

"The real significance of the assay is the polymer brush coating," said
Chilkoti. "The polymer brush allows us to store all of the tools we
need on the chip while maintaining a simple design."

While the D4 Assay is very good at grabbing small traces of specific
biomarkers, if there are only trace amounts, the fluorescent beacons
can be difficult to see. The challenge for Mikkelsen and her colleagues
was to place their plasmonic silver nanocubes above the beacons in such
a way that they supercharged the beacons' fluorescence.

But as is usually the case, this was easier said than done.

"The distance between the silver nanocubes and the gold film dictates
how much brighter the fluorescent molecule becomes," said Daniela Cruz,
a graduate student working in Mikkelsen's laboratory. "Our challenge
was to make the polymer brush coating thick enough to capture the
biomarkers -- and only the biomarkers of interest -- but thin enough to
still enhance the diagnostic lights."

The researchers attempted two approaches to solve this Goldilocks
riddle. They first added an electrostatic layer that binds to the
detector molecules that carry the fluorescent proteins, creating a sort
of "second floor" that the silver nanocubes could sit on top of. They
also tried functionalizing the silver nanocubes so that they would
stick directly to individual detector molecules on a one-on-one basis.

While both approaches succeeded in boosting the amount of light coming
from the beacons, the former showed the best improvement, increasing
its fluorescence by more than 150 times. However, this method also
requires an extra step of creating a "second floor," which adds another
hurdle to engineering a way to make this work on a commercial
point-of-care diagnostic rather than only in a laboratory. And while
the fluorescence didn't improve as much in the second approach, the
test's accuracy did.

"Building microfluidic lab-on-a-chip devices through either approach
would take time and resources, but they're both doable in theory," said
Cassio Fontes, a graduate student in the Chilkoti laboratory. "That's
what the D4 Assay is moving toward."

And the project is moving forward. Earlier in the year, the researchers
used preliminary results from this research to secure a five-year, $3.4
million R01 research award from the National Heart, Lung, and Blood
Institute. The collaborators will be working to optimize these
fluorescence enhancements while integrating wells, microfluidic
channels and other low-cost solutions into a single-step diagnostic
device that can run through all of these steps automatically and be
read by a common smartphone camera in a low-cost device.

"One of the big challenges in point-of-care tests is the ability to
read out results, which usually requires very expensive detectors,"
said Mikkelsen. "That's a major roadblock to having disposable tests to
allow patients to monitor chronic diseases at home or for use in
low-resource settings. We see this technology not only as a way to get
around that bottleneck, but also as a way to enhance the accuracy and
threshold of these diagnostic devices."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Duke University. Original written by Ken
Kingery. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Daniela F. Cruz, Cassio M. Fontes, Daria Semeniak, Jiani Huang,
Angus Hucknall, Ashutosh Chilkoti, Maiken H. Mikkelsen. Ultrabright
Fluorescence Readout of an Ink-Jet Printed Immunoassay Using
Plasmonic Nanogap Cavities. Nano Letters, 2020; DOI:
[19]10.1021/acs.nanolett.0c01051
__________________________________________________________________

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Date:
May 13, 2020

Source:
NASA/Goddard Space Flight Center

Summary:
In late May and early June, Earthlings may be able to glimpse
Comet SWAN. The comet is currently faintly visible to the
unaided eye in the Southern Hemisphere just before sunrise. The
new comet was first spotted in April 2020, by an amateur
astronomer named Michael Mattiazzo using data from the SOHO
satellite.

FULL STORY
__________________________________________________________________

In late May and early June, Earthlings may be able to glimpse Comet
SWAN. The comet is currently faintly visible to the unaided eye in the
Southern Hemisphere just before sunrise -- providing skywatchers with a
relatively rare glimpse of a comet bright enough to be seen without a
telescope. But Comet SWAN's initial discovery was made not from the
ground, but via an instrument on board ESA (the European Space Agency)
and NASA's Solar and Heliospheric Observatory, or SOHO, satellite.

The new comet was first spotted in April 2020, by an amateur astronomer
named Michael Mattiazzo using data from a SOHO instrument called Solar
Wind Anisotropies, or SWAN -- as seen [17]here. The comet appears to
leave the left side of the image and reappear on the right side around
May 3, because of the way SWAN's 360-degree all-sky maps are shown,
much like a globe is represented by a 2D map.

SWAN maps the constantly outflowing solar wind in interplanetary space
by focusing on a particular wavelength of ultraviolet light emitted by
hydrogen atoms. The new comet -- officially classified C/2020 F8 (SWAN)
but nicknamed Comet SWAN -- was spotted in the images because it's
releasing huge amounts of water, about 1.3 tons per second. As water is
made of hydrogen and oxygen, this release made Comet SWAN visible to
SOHO's instruments.

Comet SWAN is the 3,932nd comet discovered using data from SOHO. Almost
all of the nearly 4,000 discoveries have been made using data from
SOHO's coronagraph, an instrument that blocks out the Sun's bright face
using a metal disk to reveal the comparatively faint outer atmosphere,
the corona. This is only the 12th comet discovered with the SWAN
instrument since SOHO's launch in 1995, eight of which were also
discovered by Mattiazzo.

Comet SWAN makes its closest approach to Earth on May 13, at a distance
of about 53 million miles. Comet SWAN's closest approach to the Sun,
called perihelion, will happen on May 27.

Though it can be very difficult to predict the behavior of comets that
make such close approaches to the Sun, scientists are hopeful that
Comet SWAN will remain bright enough to be seen as it continues its
journey.
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__________________________________________________________________

Story Source:

[18]Materials provided by [19]NASA/Goddard Space Flight Center.
Original written by Sarah Frazier. Note: Content may be edited for
style and length.
__________________________________________________________________

Related Multimedia:
* [20]Animation showing SOHO observations of Comet SWAN
__________________________________________________________________

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Date:
May 13, 2020

Source:
NASA/Goddard Space Flight Center

Summary:
Astronomers have detected elusive pulsation patterns in dozens
of young, rapidly rotating stars thanks to data from NASA's
Transiting Exoplanet Survey Satellite (TESS).

FULL STORY
__________________________________________________________________

Astronomers have detected elusive pulsation patterns in dozens of
young, rapidly rotating stars thanks to data from NASA's Transiting
Exoplanet Survey Satellite (TESS). The discovery will revolutionize
scientists' ability to study details like the ages, sizes and
compositions of these stars -- all members of a class named for the
prototype, the bright star Delta Scuti.

"Delta Scuti stars clearly pulsate in interesting ways, but the
patterns of those pulsations have so far defied understanding," said
Tim Bedding, a professor of astronomy at the University of Sydney. "To
use a musical analogy, many stars pulsate along simple chords, but
Delta Scuti stars are complex, with notes that seem to be jumbled. TESS
has shown us that's not true for all of them."

A paper describing the findings, led by Bedding, appears in the May 14
issue of the journal Nature and is now available online.

Geologists studying seismic waves from earthquakes figured out Earth's
internal structure from the way the reverberations changed speed and
direction as they traveled through it. Astronomers apply the same
principle to study the interiors of stars through their pulsations, a
field called asteroseismology.

Sound waves travel through a star's interior at speeds that change with
depth, and they all combine into pulsation patterns at the star's
surface. Astronomers can detect these patterns as tiny fluctuations in
brightness and use them to determine the star's age, temperature,
composition, internal structure and other properties.

Delta Scuti stars are between 1.5 and 2.5 times the Sun's mass. They're
named after Delta Scuti, a star visible to the human eye in the
southern constellation Scutum that was first identified as variable in
1900. Since then, astronomers have identified thousands more like Delta
Scuti, many with NASA's Kepler space telescope, another planet-hunting
mission that operated from 2009 to 2018.

But scientists have had trouble interpreting Delta Scuti pulsations.
These stars generally rotate once or twice a day, at least a dozen
times faster than the Sun. The rapid rotation flattens the stars at
their poles and jumbles the pulsation patterns, making them more
complicated and difficult to decipher.

To determine if order exists in Delta Scuti stars' apparently chaotic
pulsations, astronomers needed to observe a large set of stars multiple
times with rapid sampling. TESS monitors large swaths of the sky for 27
days at a time, taking one full image every 30 minutes with each of its
four cameras. This observing strategy allows TESS to track changes in
stellar brightness caused by planets passing in front of their stars,
which is its primary mission, but half-hour exposures are too long to
catch the patterns of the more rapidly pulsating Delta Scuti stars.
Those changes can happen in minutes.

But TESS also captures snapshots of a few thousand pre-selected stars
-- including some Delta Scuti stars -- every two minutes. When Bedding
and his colleagues began sorting through the measurements, they found a
subset of Delta Scuti stars with regular pulsation patterns. Once they
knew what to look for, they searched for other examples in data from
Kepler, which used a similar observing strategy. They also conducted
follow-up observations with ground-based telescopes, including one at
the W.M. Keck Observatory in Hawaii and two in the global Las Cumbres
Observatory network. In total, they identified a batch of 60 Delta
Scuti stars with clear patterns.

"This really is a breakthrough. Now we have a regular series of
pulsations for these stars that we can understand and compare with
models," said co-author Simon Murphy, a postdoctoral researcher at the
University of Sydney. "It's going to allow us to measure these stars
using asteroseismology in a way that we've never been able to do. But
it's also shown us that this is just a stepping-stone in our
understanding of Delta Scuti stars."

Pulsations in the well-behaved Delta Scuti group fall into two major
categories, both caused by energy being stored and released in the
star. Some occur as the whole star expands and contracts symmetrically.
Others occur as opposite hemispheres alternatively expand and contract.
Bedding's team inferred the alterations by studying each star's
fluctuations in brightness.

The data have already helped settle a debate over the age of one star,
called HD 31901, a member of a recently discovered stream of stars
orbiting within our galaxy. Scientists placed the age of the overall
stream at 1 billion years, based on the age of a red giant they
suspected belonged to the same group. A later estimate, based on the
rotation periods of other members of the stellar stream, suggested an
age of only about 120 million years. Bedding's team used the TESS
observations to create an asteroseismic model of HD 31901 that supports
the younger age.

"Delta Scuti stars have been frustrating targets because of their
complicated oscillations, so this is a very exciting discovery," said
Sarbani Basu, a professor of astronomy at Yale University in New Haven,
Connecticut, who studies asteroseismology but was not involved in the
study. "Being able to find simple patterns and identify the modes of
oscillation is game changing. Since this subset of stars allows normal
seismic analyses, we will finally be able to characterize them
properly."

The team thinks their set of 60 stars has clear patterns because
they're younger than other Delta Scuti stars, having only recently
settled into producing all of their energy through nuclear fusion in
their cores. The pulsations occur more rapidly in the fledgling stars.
As the stars age, the frequency of the pulsations slows, and they
become jumbled with other signals.

Another factor may be TESS's viewing angle. Theoretical calculations
predict that a spinning star's pulsation patterns should be simpler
when its rotational pole faces us instead of its equator. The team's
TESS data set included around 1,000 Delta Scuti stars, which means that
some of them, by chance, must be viewed close to pole-on.

Scientists will continue to develop their models as TESS begins taking
full images every 10 minutes instead of every half hour in July.
Bedding said the new observing strategy will help capture the
pulsations of even more Delta Scuti stars.

"We knew when we designed TESS that, in addition to finding many
exciting new exoplanets, the satellite would also advance the field of
asteroseismology," said TESS Principal Investigator George Ricker at
the Massachusetts Institute of Technology's Kavli Institute for
Astrophysics and Space Research in Cambridge. "The mission has already
found a new type of star that pulsates on one side only and has
unearthed new facts about well-known stars. As we complete the initial
two-year mission and commence the extended mission, we're looking
forward to a wealth of new stellar discoveries TESS will make."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]NASA/Goddard Space Flight Center.
Original written by Jeanette Kazmierczak. Note: Content may be edited
for style and length.
__________________________________________________________________

Related Multimedia:
* [19]Video illustrating pulsations of a Delta Scuti star; animation
showing sound waves bouncing around inside a star cause it to
expand and contract; the rapid beat of HD 31901, a Delta Scuti star
in the southern constellation Lepus
__________________________________________________________________

Journal Reference:
1. Timothy R. Bedding, Simon J. Murphy, Daniel R. Hey, Daniel Huber,
Tanda Li, Barry Smalley, Dennis Stello, Timothy R. White, Warrick
H. Ball, William J. Chaplin, Isabel L. Colman, Jim Fuller, Eric
Gaidos, Daniel R. Harbeck, J. J. Hermes, Daniel L. Holdsworth, Gang
Li, Yaguang Li, Andrew W. Mann, Daniel R. Reese, Sanjay Sekaran,
Jie Yu, Victoria Antoci, Christoph Bergmann, Timothy M. Brown,
Andrew W. Howard, Michael J. Ireland, Howard Isaacson, Jon M.
Jenkins, Hans Kjeldsen, Curtis McCully, Markus Rabus, Adam D.
Rains, George R. Ricker, Christopher G. Tinney, Roland K.
Vanderspek. Very regular high-frequency pulsation modes in young
intermediate-mass stars. Nature, 2020; 581 (7807): 147 DOI:
[20]10.1038/s41586-020-2226-8
__________________________________________________________________

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Researchers simulate the core of Mars to investigate its composition and
origin

Date:
May 13, 2020

Source:
University of Tokyo

Summary:
Earth-based experiments on iron-sulfur alloys thought to
comprise the core of Mars reveal details about the planet's
seismic properties for the first time. This information will be
compared to observations made by Martian space probes in the
near future. Whether the results between experiment and
observation coincide or not will either confirm existing
theories about Mars' composition or call into question the story
of its origin.

FULL STORY
__________________________________________________________________

Earth-based experiments on iron-sulfur alloys thought to comprise the
core of Mars reveal details about the planet's seismic properties for
the first time. This information will be compared to observations made
by Martian space probes in the near future. Whether the results between
experiment and observation coincide or not will either confirm existing
theories about Mars' composition or call into question the story of its
origin.

Mars is one of our closest terrestrial neighbors, yet it's still very
far away -- between about 55 million and 400 million kilometers
depending on where Earth and Mars are relative to the sun. At the time
of writing, Mars is around 200 million kilometers away, and in any
case, it is extremely difficult, expensive and dangerous to get to. For
these reasons, it is sometimes more sensible to investigate the red
planet through simulations here on Earth than it is to send an
expensive space probe or, perhaps one day, people.

Keisuke Nishida, an Assistant Professor from the University of Tokyo's
Department of Earth and Planetary Science at the time of the study, and
his team are keen to investigate the inner workings of Mars. They look
at seismic data and composition which tell researchers not just about
the present state of the planet, but also about its past, including its
origins.

"The exploration of the deep interiors of Earth, Mars and other planets
is one of the great frontiers of science," said Nishida. "It's
fascinating partly because of the daunting scales involved, but also
because of how we investigate them safely from the surface of the
Earth."

For a long time it has been theorized that the core of Mars probably
consists of an iron-sulfur alloy. But given how inaccessible the
Earth's core is to us, direct observations of Mars' core will likely
have to wait some time. This is why seismic details are so important,
as seismic waves, akin to enormously powerful sound waves, can travel
through a planet and offer a glimpse inside, albeit with some caveats.

"NASA's Insight probe is already on Mars collecting seismic readings,"
said Nishida. "However, even with the seismic data there was an
important missing piece of information without which the data could not
be interpreted. We needed to know the seismic properties of the
iron-sulfur alloy thought to make up the core of Mars."

Nishida and team have now measured the velocity for what is known as
P-waves (one of two types of seismic wave, the other being S-waves) in
molten iron-sulfur alloys.

"Due to technical hurdles, it took more than three years before we
could collect the ultrasonic data we needed, so I am very pleased we
now have it," said Nishida. "The sample is extremely small, which might
surprise some people given the huge scale of the planet we are
effectively simulating. But microscale high-pressure experiments help
exploration of macroscale structures and long time-scale evolutionary
histories of planets."

A molten iron-sulfur alloy just above its melting point of 1,500
degrees Celsius and subject to 13 gigapascals of pressure has a P-Wave
velocity of 4,680 meters per second; this is over 13 times faster than
the speed of sound in air, which is 343 meters per second. The
researchers used a device called a Kawai-type multianvil press to
compress the sample to such pressures. They used X-ray beams from two
synchrotron facilities, KEK-PF and SPring-8, to help them image the
samples in order to then calculate the P-wave values.

"Taking our results, researchers reading Martian seismic data will now
be able to tell whether the core is primarily iron-sulfur alloy or
not," said Nishida. "If it isn't, that will tell us something of Mars'
origins. For example, if Mars' core includes silicon and oxygen, it
suggests that, like the Earth, Mars suffered a huge impact event as it
formed. So, what is Mars made of and how was it formed? I think we are
about to find out."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Tokyo. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Keisuke Nishida, Yuki Shibazaki, Hidenori Terasaki, Yuji Higo, Akio
Suzuki, Nobumasa Funamori, Kei Hirose. Effect of sulfur on sound
velocity of liquid iron under Martian core conditions. Nature
Communications, 2020; 11 (1) DOI: [19]10.1038/s41467-020-15755-2
__________________________________________________________________

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Date:
May 13, 2020

Source:
Brigham Young University

Summary:
A recent six-year study, the longest study ever done on video
game addiction, found that about 90% of gamers do not play in a
way that is harmful or causes negative long-term consequences. A
significant minority, though, can become truly addicted to video
games and as a result can suffer mentally, socially and
behaviorally.

FULL STORY
__________________________________________________________________

For most adolescents, playing video games is an enjoyable and often
social form of entertainment. While playing video games is a fun
pastime, there is a growing concern that spending too much time playing
video games is related to negative developmental outcomes and can
become an addiction.

A recent six-year study, the longest study ever done on video game
addiction, found that about 90% of gamers do not play in a way that is
harmful or causes negative long-term consequences. A significant
minority, though, can become truly addicted to video games and as a
result can suffer mentally, socially and behaviorally.

"The aim of this particular study is to look at the longer-term impact
of having a particular relationship with video games and what it does
to a person over time," said Sarah Coyne, a professor of family life at
BYU and lead author of the research. "To see the impact, we examined
the trajectories of pathological video gameplay across six years, from
early adolescence to emerging adulthood."

In addition to finding long-term consequences for addicted gamers, this
study, published in Developmental Psychology, also breaks down gamer
stereotypes and found that pathological gaming is not a one size fits
all disorder.

Pathological video gameplay is characterized by excessive time spent
playing video games, difficulty disengaging from them and disruption to
healthy functioning due to gaming.

Only about 10% of gamers fall into the pathological video gameplay
category. When compared to the non-pathological group, those in the
study displayed higher levels of depression, aggression, shyness,
problematic cell phone use and anxiety by emerging adulthood. This was
despite the groups being the same in all these variables at the initial
time point, suggesting that video games may have been important in
developing these negative outcomes.

To measure predictors and outcomes to video game addiction, Coyne
studied 385 adolescents as they transitioned into adulthood. Each
individual completed multiple questionnaires once a year over a
six-year period. These questionnaires measured depression, anxiety,
aggression, delinquency, empathy, prosocial behavior, shyness, sensory
reactivity, financial stress and problematic cell phone use.

Two main predictors for video game addiction were found: being male and
having low levels of prosocial behavior. Having higher levels of
prosocial behavior, or voluntary behavior meant to benefit another
person, tended to be a protective factor against the addiction
symptoms.

Aside from the predictors, Coyne also found three distinct trajectories
of video game use. Seventy-two percent of adolescents were relatively
low in addiction symptoms across the six years of data collection.
Another 18% of adolescents started with moderate symptoms that did not
change over time, and only 10% of adolescents showed increasing levels
of pathological gaming symptoms throughout the study.

The results suggest that while about 90% of gamers are not playing in a
way that is dysfunctional or detrimental to the individual's life,
there is still a sizable minority who are truly addicted to video games
and suffer addiction symptoms over time.

These findings also go against the stereotype of gamers living in their
parent's basement, unable to support themselves financially or get a
job because of their fixation on video games. At least in their early
twenties, pathological users of video games appear to be just as
financially stable and forward-moving as gamers who are not addicted.

"I really do think that there are some wonderful things about video
games," Coyne said. "The important thing is to use them in healthy ways
and to not get sucked into the pathological levels."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Brigham Young University. Original
written by Cami Buckley. Note: Content may be edited for style and
length.
__________________________________________________________________

Journal Reference:
1. Sarah M. Coyne, Laura A. Stockdale, Wayne Warburton, Douglas A.
Gentile, Chongming Yang, Brett M. Merrill. Pathological video game
symptoms from adolescence to emerging adulthood: A 6-year
longitudinal study of trajectories, predictors, and outcomes..
Developmental Psychology, 2020; DOI: [19]10.1037/dev0000939
__________________________________________________________________

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3D interface provides cellular-level, full-body blood flow modeling to study and treat cardiovascular disease

Date:
May 13, 2020

Source:
Duke University

Summary:
Biomedical engineers are developing a massive fluid dynamics
simulator that can model blood flow through the full human
arterial system at subcellular resolution. One of the goals of
the effort is to provide doctors with a virtual reality system
that can guide their treatment plans by allowing them to
simulate a patient's specific vasculature and accurately predict
how decisions such as stent placement, conduit insertions and
other geometric alterations will affect surgical outcomes.

FULL STORY
__________________________________________________________________

Biomedical engineers at Duke University are developing a massive fluid
dynamics simulator that can model blood flow through the full human
arterial system at subcellular resolution. One of the goals of the
effort is to provide doctors with guidance in their treatment plans by
allowing them to simulate a patient's specific vasculature and
accurately predict how decisions such as stent placement, conduit
insertions and other geometric alterations to blood flow will affect
surgical outcomes.

One of the largest barriers to clinical adoption however, is developing
a user interface that allows clinicians to easily explore their options
without needing any expertise in computer science. As any programmer
will tell you, designing a smooth, intuitive interface that people from
all types of backgrounds can quickly master is a tall task.

In a new study published on May 7 in the Journal of Computational
Science, the Duke researchers report on their initial foray into
creating a user interface for their blood flow simulation tool called
HARVEY. They explored various interfaces ranging from standard desktop
displays to immersive virtual reality experiences and found that, while
users might be comfortable using a standard mouse and keyboard, some
more futuristic interfaces might hold the key to widespread adoption.

"HARVEY currently requires knowledge of C coding and command line
interfaces, which really limits who can use the program," said Amanda
Randles, the Alfred Winborne and Victoria Stover Mordecai Assistant
Professor of Biomedical Sciences at Duke. "This paper introduces a
graphical user interface we've developed called Harvis, so that anybody
can use Harvey, whether they're surgeons trying to figure out the best
placement for a stent or biomedical researchers trying to design a new
type of stent altogether."

Randles has been developing the HARVEY code for nearly a decade, having
begun the work as a doctoral student in the research group of Efthimios
Kaxiras, the John Hasbrouck Van Vleck Professor of Pure and Applied
Physics at Harvard University. In that time, she has demonstrated that
HARVEY can accurately model blood flow through patient-specific aortas
and other vascular geometries on longer scales. She's also shown the
program can model 3D blood flows on the scale of the full human body.

Putting HARVEY to work, Randles has helped researchers understand stent
treatment of cerebral aneurysms and the growth of aneurysms. She has
created a quick, noninvasive way to check for peripheral arterial
disease, and to better understand how circulating cancer cells adhere
to different tissues. With steady progress on the computational
abilities of the code and demonstrated usefulness in real-world
applications, Randles is now working to make sure others can make the
best use of its abilities.

"As cardiovascular disease continues to be the number one cause of
death in the US, the ability to improve treatment planning and outcome
remains a significant challenge," said Randles. "With the maturity and
availability of VR/AR devices, we need to understand the role these
technologies can play in the interaction with such data. This research
is a much-needed step for developing future software to combat
cardiovascular disease."

In the new study, Randles and her biomedical engineering colleagues,
research associate Harvey Shi and graduate student Jeff Ames, put the
Harvis interface they've been developing to the test. They asked
medical students and biomedical researchers to simulate three different
situations -- placing a conduit between two blood vessels, expanding or
shrinking the size of a blood vessel, or placing a stent within a blood
vessel. The test users attempted these tasks using either a standard
mouse and computer screen, a "Z-space" semi-immersive virtual reality
device, or a fully immersive virtual reality experience with an HTC
Vive display device.

The results show that the students and researchers could use the
standard mouse and keyboard interface and the fully immersive VR
interface equally as well in a majority of cases both quantitatively
and qualitatively. The semi-immersive display, basically a special
pointing tool combined with a monitor and 3D glasses, however, ranked
behind the other two devices, as the users had some issues adjusting to
the unique hardware setup and controls.

The study also presents a generalizable design architecture for other
simulated workflows, laying out a detailed description of the rationale
for the design of Harvis, which can be extended to similar platforms.

While the study did not find any major differences between the most and
least immersive interfaces in terms of quality and efficiency, Randles
did notice a major difference between the users' reactions to the
equipment.

"People enjoyed the 3D interface more," said Randles. "And if they
enjoyed it more, they're more likely to actually use it. It could also
be a fun and exciting way to get students engaged in classes about the
vasculature system and hemodynamics."

Randles says she plans on running experiments to see if her 3D blood
flow interface can help medical students retain important knowledge
better than current standards. In the future, tools like this could
assist with treatment planning such as placements of stents using a
more intuitive virtual reality interface. Randles also expects these
types of tools will facilitate biomedical research in the personalized
flow space.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Duke University. Original written by Ken
Kingery. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Harvey Shi, Jeff Ames, Amanda Randles. Harvis: an interactive
virtual reality tool for hemodynamic modification and simulation.
Journal of Computational Science, 2020; 101091 DOI:
[19]10.1016/j.jocs.2020.101091
__________________________________________________________________

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online

Researchers warn scientists are fighting health misinformation in the wrong place

Date:
May 13, 2020

Source:
George Washington University

Summary:
Communities on Facebook that distrust establishment health
guidance are more effective than government health agencies and
other reliable health groups at reaching and engaging
'undecided' individuals, according to a new study.

FULL STORY
__________________________________________________________________

Communities on Facebook that distrust establishment health guidance are
more effective than government health agencies and other reliable
health groups at reaching and engaging "undecided" individuals,
according to a study published today in the journal Nature.

Researchers at the George Washington University developed a
first-of-its-kind map to track the vaccine conversation among 100
million Facebook users during the height of the 2019 measles outbreak.
The new study and its "battleground" map reveal how distrust in
establishment health guidance could spread and dominate online
conversations over the next decade, potentially jeopardizing public
health efforts to protect populations from COVID-19 and future
pandemics through vaccinations.

Professor Neil Johnson and his GW research team, including professor
Yonatan Lupu and researchers Nicolas Velasquez, Rhys Leahy and Nico
Restrepo, collaborated with researchers at the University of Miami,
Michigan State University and Los Alamos National Laboratory to better
understand how distrust in scientific expertise evolves online,
especially related to vaccines.

"There is a new world war online surrounding trust in health expertise
and science, particularly with misinformation about COVID-19, but also
distrust in big pharmaceuticals and governments," Dr. Johnson said.
"Nobody knew what the field of battle looked like, though, so we set to
find out."

During the 2019 measles outbreak, the research team examined Facebook
communities, totaling nearly 100 million users, which were active
around the vaccine topic and which formed a highly dynamic,
interconnected network across cities, countries, continents and
languages. The team identified three camps comprising pro-vaccination
communities, anti-vaccination communities and communities of undecided
individuals such as parenting groups. Starting with one community, the
researchers looked to find a second one that was strongly entangled
with the original, and so on, to better understand how they interacted
with each other.

They discovered that, while there are fewer individuals with
anti-vaccination sentiments on Facebook than with pro-vaccination
sentiments, there are nearly three times the number of anti-vaccination
communities on Facebook than pro-vaccination communities. This allows
anti-vaccination communities to become highly entangled with undecided
communities, while pro-vaccination communities remain mostly
peripheral. In addition, pro-vaccination communities which focused on
countering larger anti-vaccination communities may be missing
medium-sized ones growing under the radar.

The researchers also found anti-vaccination communities offer more
diverse narratives around vaccines and other established health
treatments -- promoting safety concerns, conspiracy theories or
individual choice, for example -- that can appeal to more of Facebook's
approximately 3 billion users, thus increasing the chances of
influencing individuals in undecided communities. Pro-vaccination
communities, on the other hand, mostly offered monothematic messaging
typically focused on the established public health benefits of
vaccinations. The GW researchers noted that individuals in these
undecided communities, far from being passive bystanders, were actively
engaging with vaccine content.

"We thought we would see major public health entities and state-run
health departments at the center of this online battle, but we found
the opposite. They were fighting off to one side, in the wrong place,"
Dr. Johnson said.

As scientists around the world scramble to develop an effective
COVID-19 vaccine, the spread of health disinformation and
misinformation has important public health implications, especially on
social media, which often serves as an amplifier and information
equalizer. In their study, the GW researchers proposed several
different strategies to fight against online disinformation, including
influencing the heterogeneity of individual communities to delay onset
and decrease their growth and manipulating the links between
communities in order to prevent the spread of negative views.

"Instead of playing whack-a-mole with a global network of communities
that consume and produce (mis)information, public health agencies,
social media platforms and governments can use a map like ours and an
entirely new set of strategies to identify where the largest theaters
of online activity are and engage and neutralize those communities
peddling in misinformation so harmful to the public," Dr. Johnson said.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]George Washington University. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Neil F. Johnson, Nicolas Velásquez, Nicholas Johnson Restrepo, Rhys
Leahy, Nicholas Gabriel, Sara El Oud, Minzhang Zheng, Pedro
Manrique, Stefan Wuchty, Yonatan Lupu. The online competition
between pro- and anti-vaccination views. Nature, 2020; DOI:
[19]10.1038/s41586-020-2281-1
__________________________________________________________________

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Date:
May 13, 2020

Source:
University of Massachusetts Amherst

Summary:
Scientists report that they have developed bioelectronic ammonia
gas sensors that are among the most sensitive ever made. It uses
electric-charge-conducting protein nanowires derived from the
bacterium Geobacter to provide biomaterials for electrical
devices. They grow hair-like protein filaments that work as
nanoscale ''wires'' to transfer charges for their nourishment
and to communicate with other bacteria.

FULL STORY
__________________________________________________________________

Writing in the journal NanoResearch, a team at the University of
Massachusetts Amherst reports this week that they have developed
bioelectronic ammonia gas sensors that are among the most sensitive
ever made.

The sensor uses electric-charge-conducting protein nanowires derived
from the bacterium Geobacter to provide biomaterials for electrical
devices. More than 30 years ago, senior author and microbiologist Derek
Lovley discovered Geobacter in river mud. The microbes grow hair-like
protein filaments that work as nanoscale "wires" to transfer charges
for their nourishment and to communicate with other bacteria.

First author and biomedical engineering doctoral student Alexander
Smith, with his advisor Jun Yao and Lovley, say they designed this
first sensor to measure ammonia because that gas is important to
agriculture, the environment and biomedicine. For example, in humans,
ammonia on the breath may signal disease, while in poultry farming, the
gas must be closely monitored and controlled for bird health and
comfort and to avoid feed imbalances and production losses.

Yao says, "This sensor allows you to do high-precision sensing; it's
much better than previous electronic sensors." Smith adds, "Every time
I do a new experiment, I'm pleasantly surprised. We didn't expect them
to work as well as they have. I really think they could have a real
positive impact on the world."

Smith says existing electronic sensors often have either limited or low
sensitivity, and they are prone to interference from other gases. In
addition to superior function and low cost, he adds, "our sensors are
biodegradable so they do not produce electronic waste, and they are
produced sustainably by bacteria using renewable feedstocks without the
need for toxic chemicals."

Smith conducted the experiments over the past 18 months as part of his
Ph.D. work. It was known from Lovley's earlier studies that the protein
nanowires' conductivity changed in response to pH -- the acid or base
level- of solution around the protein nanowires. This moved the
researchers to test the idea that they could be highly responsive to
molecule binding for biosensing. "If you expose them to a chemical, the
properties change and you can measure the response," Smith notes.

When he exposed the nanowires to ammonia, "the response was really
noticeable and significant," Smith says. "Early on, we found we could
tune the sensors in a way that shows this significant response. They
are really sensitive to ammonia and much less to other compounds, so
the sensors can be very specific."

Lovley adds, that the "very stable" nanowires last a long time, the
sensor functions consistently and robustly after months of use, and
work so well "it is remarkable."

Yao says, "These protein nanowires are always amazing me. This new use
is in a completely different area than we had worked in before."
Previously, the team has reported using protein nanowires to harvest
energy from humidity and applying them as memristors for biological
computing.

Smith, who calls himself "entrepreneurial," won first place in UMass
Amherst's 2018 Innovation Challenge for the startup business plan for
the company he formed with Yao and Lovley, e-Biologics. The researchers
have followed up with a patent application, fundraising, business
development and research and development plans.

Lovley says, "This work is the first proof-of-concept for the nanowire
sensor. Once we get back in the lab, we'll develop sensors for other
compounds. We are working on tuning them for an array of other
compounds."

Support for the work came as a CAREER grant and Graduate Research
Fellowship from the National Science Foundation, UMass Amherst's Office
of Technology Commercialization and Ventures and the campus's Center
for Hierarchical Manufacturing, an NSF-funded Nanoscale Science and
Engineering Center.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Massachusetts Amherst.
Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Alexander F. Smith, Xiaomeng Liu, Trevor L. Woodard, Tianda Fu,
Todd Emrick, Juan M. Jiménez, Derek R. Lovley, Jun Yao.
Bioelectronic protein nanowire sensors for ammonia detection. Nano
Research, 2020; DOI: [19]10.1007/s12274-020-2825-6
__________________________________________________________________

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New research could lead to safely reusable PPE

Date:
May 13, 2020

Source:
University of Pittsburgh

Summary:
Researchers have created a textile coating that can not only
repel liquids like blood and saliva but can also prevent viruses
from adhering to the surface.

FULL STORY
__________________________________________________________________

Masks, gowns, and other personal protective equipment (PPE) are
essential for protecting healthcare workers. However, the textiles and
materials used in such items can absorb and carry viruses and bacteria,
inadvertently spreading the disease the wearer sought to contain.

When the coronavirus spread amongst healthcare professionals and left
PPE in short supply, finding a way to provide better protection while
allowing for the safe reuse of these items became paramount.

Research from the LAMP Lab at the University of Pittsburgh Swanson
School of Engineering may have a solution. The lab has created a
textile coating that can not only repel liquids like blood and saliva
but can also prevent viruses from adhering to the surface. The work was
recently published in the journal ACS Applied Materials and Interfaces.

"Recently there's been focus on blood-repellent surfaces, and we were
interested in achieving this with mechanical durability," said Anthony
Galante, PhD student in industrial engineering at Pitt and lead author
of the paper. "We want to push the boundary on what is possible with
these types of surfaces, and especially given the current pandemic, we
knew it'd be important to test against viruses."

What makes the coating unique is its ability to withstand ultrasonic
washing, scrubbing and scraping. With other similar coatings currently
in use, washing or rubbing the surface of the textile will reduce or
eliminate its repellent abilities.

"The durability is very important because there are other surface
treatments out there, but they're limited to disposable textiles. You
can only use a gown or mask once before disposing of it," said Paul
Leu, co-author and associate professor of industrial engineering, who
leads the LAMP Lab. "Given the PPE shortage, there is a need for
coatings that can be applied to reusable medical textiles that can be
properly washed and sanitized."

Galante put the new coating to the test, running it through tens of
ultrasonic washes, applying thousands of rotations with a scrubbing pad
(not unlike what might be used to scour pots and pans), and even
scraping it with a sharp razor blade. After each test, the coating
remained just as effective.

The researchers worked with the Charles T. Campbell Microbiology
Laboratory's Research Director Eric Romanowski and Director of Basic
Research Robert Shanks, in the Department of Ophthalmology at Pitt, to
test the coating against a strain of adenovirus.

"As this fabric was already shown to repel blood, protein and bacteria,
the logical next step was to determine whether it repels viruses. We
chose human adenovirus types 4 and 7, as these are causes of acute
respiratory disease as well as conjunctivitis (pink eye)," said
Romanowski. "It was hoped that the fabric would repel these viruses
similar to how it repels proteins, which these viruses essentially are:
proteins with nucleic acid inside. As it turned out, the adenoviruses
were repelled in a similar way as proteins."

The coating may have broad applications in healthcare: everything from
hospital gowns to waiting room chairs could benefit from the ability to
repel viruses, particularly ones as easily spread as adenoviruses.

"Adenovirus can be inadvertently picked up in hospital waiting rooms
and from contaminated surfaces in general. It is rapidly spread in
schools and homes and has an enormous impact on quality of life --
keeping kids out of school and parents out of work," said Shanks. "This
coating on waiting room furniture, for example, could be a major step
towards reducing this problem."

The next step for the researchers will be to test the effectiveness
against betacoronaviruses, like the one that causes COVID-19.

"If the treated fabric would repel betacornonaviruses, and in
particular SARS-CoV-2, this could have a huge impact for healthcare
workers and even the general public if PPE, scrubs, or even clothing
could be made from protein, blood-, bacteria-, and virus-repelling
fabrics," said Romanowski.

At the moment, the coating is applied using drop casting, a method that
saturates the material with a solution from a syringe and applies a
heat treatment to increase stability. But the researchers believe the
process can use a spraying or dipping method to accommodate larger
pieces of material, like gowns, and can eventually be scaled up for
production.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Pittsburgh. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Anthony J. Galante, Sajad Haghanifar, Eric G. Romanowski, Robert M.
Q. Shanks, Paul W. Leu. Superhemophobic and Antivirofouling Coating
for Mechanically Durable and Wash-Stable Medical Textiles. ACS
Applied Materials & Interfaces, 2020; 12 (19): 22120 DOI:
[19]10.1021/acsami.9b23058
__________________________________________________________________

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Date:
May 13, 2020

Source:
Max Planck Institute for the Science of Human History

Summary:
Due to the improvement and increased use of geochemical
fingerprinting techniques during the last 25 years, the
archaeological compositional data of stone tools has grown
exponentially. The Pofatu Database is a large-scale
collaborative project that enables curation and data sharing.
The database also provides instrumental details, analytical
procedures and reference standards used for calibration purposes
or quality control. Thus, Pofatu ensures reproducibility and
comparability between provenance studies.

FULL STORY
__________________________________________________________________

Due to the improvement and increased use of geochemical fingerprinting
techniques during the last 25 years, the archaeological compositional
data of stone tools has grown exponentially. The Pofatu Database is a
large-scale collaborative project that enables curation and data
sharing. The database also provides instrumental details, analytical
procedures and reference standards used for calibration purposes or
quality control. Thus, Pofatu ensures reproducibility and comparability
between provenance studies.

Provenance studies (documenting where artefacts are found relative to
their sources or place of manufacture) help archaeologists understand
the "life-histories" of artefacts, in this case, stone tools. They show
where the raw material come from and how artefacts were manufactured
and distributed between individuals and groups. Reliable data allows
scientists to reconstruct technological, economic, and social behaviors
of human societies over many thousands of years.

To facilitate access to this growing body of geochemical data, Aymeric
Hermann and Robert Forkel of the Department for Linguistic and Cultural
Evolution, Max Planck Institute for the Science of Human History,
conceived and designed Pofatu, the first open-access database of
geochemical compositions and contextual information for archaeological
sources and artefacts in a form readily accessible to the scientific
community.

Reconstructing ancient strategies of raw material and artefact
procurement

Geochemical "fingerprinting" of artefacts is the most effective way to
reconstruct how and where ancient peoples extracted, transformed, and
exchanged stone materials and artefacts. These fingerprints also serve
as clues to understand a number of phenomenon in past human societies,
such as technical and economic behaviors, as well as sociopolitical
organizations.

The Pofatu Database provides researchers with access to an
ever-expanding dataset and facilitates comparability and
reproducibility in provenance studies. Each sample is comprehensively
documented for elemental and isotopic compositions, and includes
detailed archaeological provenance, as well as supporting analytical
metadata, such as sampling processes, analytical procedures, and
quality control.

"By providing analytical data and comprehensive archaeological details
in a form that can be readily accessed by the scientific community,"
Hermann says, "the Pofatu Database will facilitate assigning
unambiguous provenance to artefacts in future studies and will lead to
more robust, large-scope modelling of long-distance voyaging and
traditional exchange systems."

Additionally, Marshall Weisler, a collaborator in the Pofatu project
from the University of Queensland in Australia, stated that "By tracing
the transport of artefacts carried across the wide expanse of the
Pacific Ocean, we will be able to reconstruct the ancient journeys
enabling the greatest maritime migration in human history."

Pofatu -- an operational framework for data sharing in archaeometry

Pofatu's structure was designed by Forkel and Hermann. Hermann compiled
and described the data with contributions and validations by colleagues
and co-authors from universities and research institutions in New
Zealand, Australia, and the USA. The database uses GitHub for
open-source storage and version control and common non-proprietary file
formats (CSV) to enable transparency and built-in reproducibility for
future studies of prehistoric exchange. The database currently contains
7759 individual samples from archaeological sites and geological
sources across the Pacific Islands, but Pofatu is made for even more,
Hermann notes.

"With Pofatu we activated an operational framework for data sharing in
archaeometry. The database is currently focused on sites and
collections from the Pacific Islands, but we welcome all contributions
of geochemical data on archaeological material, regardless of
geographic or chrono-cultural boundaries. Our vision is an inclusive
and collaborative data resource that will hopefully continue to develop
with more datasets from the Pacific as well as from other regions. The
ultimate goal is a more global project contemporary to other existing
online repositories for geological materials."

Although the Pofatu Database is meant to be used primarily by
archaeologists, analyses of geological samples and raw material
extracted from prehistoric quarries could also be used by geologists to
gather essential information on the smaller or more remote Pacific
islands, which are among the least studied places on the planet and
sometimes lack geochemical documentation. In that sense, Pofatu is a
tool that will facilitate interdisciplinary research.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Max Planck Institute for the Science of
Human History. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Aymeric Hermann, Robert Forkel, Andrew McAlister, Arden
Cruickshank, Mark Golitko, Brendan Kneebone, Mark McCoy, Christian
Reepmeyer, Peter Sheppard, John Sinton, Marshall Weisler. Pofatu, a
curated and open-access database for geochemical sourcing of
archaeological materials. Scientific Data, 2020; 7 (1) DOI:
[19]10.1038/s41597-020-0485-8
__________________________________________________________________

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Multi-scale structured materials for electrocatalysis and
photoelectrocatalysis

Date:
May 13, 2020

Source:
Technische Universität Dresden

Summary:
Chemists developed a freeze-thaw method, capable of synthesizing
various noble metal aerogels (NMAs) with clean surfaces and
multiscale structure. In virtue of their hierarchical structures
and unique optical properties, outstanding performance for
electro-oxidation of ethanol is found. The research provides new
ideas for designing various gel or foam materials for
high-performance electrocatalysis and photoelectrocatalysis.

FULL STORY
__________________________________________________________________

As a new class of porous materials, noble metal aerogels (NMAs) have
drawn tremendous attention because of their combined features including
self-supported architectures, high surface areas, and numerous
optically and catalytically active sites, enabling their impressive
performance in diverse fields. However, current fabrication methods
suffer from long fabrication periods, unavoidable impurities, and
uncontrolled multiscale structures, discouraging their fundamental and
application-orientated studies.

Dr. Ran Du from China has been an Alexander von Humboldt research
fellow at TU Dresden since 2017. In collaboration with the Dresden
chemists Dr. Jan-Ole Joswig and Professor Alexander Eychmüller, they
recently crafted a novel freeze-thaw method capable of acquiring
various multi-scale structured noble metal aerogels as superior
photoelectrocatalysts for electro-oxidation of ethanol, promoting the
application for fuel cells. Their work has now been published as cover
story in the journal Angewandte Chemie International Edition.

Ran Du and his team have found unusual self-healing properties of noble
metal gels in their previous works. Inspired by this fact, a
freeze-thaw method was developed as an additive-free approach to
directly destabilise various dilute metal nanoparticle solutions
(concentration of 0.2-0.5 mM). Upon freezing, large aggregates were
generated due to the intensified salting-out effects incurred by the
dramatically raised local solute concentration; meanwhile, they were
shaped at micrometer scale by in situ formed ice crystals. After
thawing, aggregates settled down and assembled to monolithic hydrogels
as a result of their self-healing properties. Purified and dried, clean
hydrogels and the corresponding aerogels were obtained.

Due to the hierarchically porous structures, the cleanliness, and the
combined catalytic/optical properties, the resulting gold-palladium
(Au-Pd) aerogels were found to display impressive light-driven
photoelectrocatalytic performance, delivering a current density of up
to 6.5 times higher than that of commercial palladium-on-carbon (Pd/C)
for the ethanol oxidation reaction.

"The current work provides a new idea to create clean and
hierarchically structured gel materials directly from dilute precursor
solutions, and it should adapt to various material systems for enhanced
application performance for catalysis and beyond," assumes chemist Ran
Du.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Technische Universität Dresden. Note:
Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Ran Du, Jan-Ole Joswig, René Hübner, Lin Zhou, Wei Wei, Yue Hu,
Alexander Eychmüller. Freeze-Thaw-Promoted Fabrication of Clean and
Hierarchically Structured Noble-Metal Aerogels for Electrocatalysis
and Photoelectrocatalysis. Angewandte Chemie International Edition,
2020; DOI: [19]10.1002/anie.201916484
__________________________________________________________________

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Date:
May 13, 2020

Source:
Cell Press

Summary:
Wind plants in the United States remain relatively efficient
over time, with only a 13% drop in performance over 17 years,
researchers report. Their study also suggests that a production
tax credit provides an effective incentive to maintain the
plants during the 10-year window in which they are eligible to
receive it. When this window closes, wind plant performance
drops.

FULL STORY
__________________________________________________________________

Wind plants in the United States -- especially the newest models --
remain relatively efficient over time, with only a 13% drop in the
plants' performance over 17 years, researchers at the Lawrence Berkeley
National Laboratory report in the May 13 issue of the journal Joule.
Their study also suggests that a production tax credit provides an
effective incentive to maintain the plants during the 10-year window in
which they are eligible to receive it. When this tax credit window
closes, wind plant performance drops.

"Since wind plant operators are now receiving less revenue after the
tax credit expires, the effective payback period to recoup the costs of
any maintenance expenditure is longer," says study author Dev
Millstein, a research scientist at Lawrence Berkeley National
Laboratory. "Due to this longer payback period, we hypothesize that
plants may choose to spend less on maintenance overall, and their
performance may therefore drop."

Wind power is on the rise, supplying 7.3% of electricity generation in
the United States in 2019 and continuing to grow around the world due
to its low cost and ability to help states and countries reach their
carbon emission reduction goals. But while the technology is highly
promising, it isn't infallible -- like any engineered system, wind
plant performance declines with age, although the rate of decline
varies based on the location of the plant. In order to understand the
potential growth of this technology and its ability to impact
electricity systems, accurate estimates of future wind plant
performance are essential.

Building from previous research with a European focus, Millstein and
colleagues assessed the US onshore wind fleet, evaluating the
performance of 917 US wind plants (including newer plants introduced in
2008 or later as well as older plants) over a 10-year period. Since
measurements of long-term wind speed are typically not available for a
given location, the researchers determined wind speed using global
reanalysis data, accounting for shifts in available wind from one year
to the next. They obtained data on the energy generated from each plant
from the US Energy Information Administration, which tracks electricity
generation from each plant on a monthly basis, and they performed a
statistical analysis to determine the average rate of age-related
performance decline across the entire fleet.

Millstein and colleagues found significant differences in performance
decline between the older and younger wind plant models, with older
vintages declining by 0.53% each year for the first 10 years while
their younger counterparts declined by only 0.17% per year during the
same decade.

But a notable change occurred as soon as the plants turned 10 years old
-- a trend in decline that has not been observed in Europe. As soon as
the plants lost their eligibility for a production tax credit of 2.3
cents per kilowatt-hour, their performance began dropping at a yearly
rate of 3.6%.

Still, the researchers are optimistic about the ability of US wind
plants to weather the years.

"We found that performance decline with age for US plants was on the
lower end of the spectrum found from wind fleets in other countries,
specifically compared to European research studies," says Millstein.
"This is generally good news for the US wind fleet. This study will
help people account for a small amount of performance loss with age
while not exaggerating the magnitude of such losses."

As the wind energy sector continues to swell, the researchers note that
their findings can be used to inform investors, operators, and energy
modelers, enabling accurate long-term wind plant energy production
estimates and guiding the development of an evolving electrical grid.

"The hope is that, overall, the improved estimates of wind generation
and costs will lead to more effective decision making from industry,
academia, and policy makers," says Millstein.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

Materials provided by [17]Cell Press. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. Sofia D. Hamilton, Dev Millstein, Mark Bolinger, Ryan Wiser,
Seongeun Jeong. How Does Wind Project Performance Change with Age
in the United States? Joule, 2020; DOI:
[18]10.1016/j.joule.2020.04.005
__________________________________________________________________

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Date:
May 13, 2020

Source:
Graz University of Technology

Summary:
Researchers have developed ultra-light tattoo electrodes that
are hardly noticeable on the skin and make long-term
measurements of brain activity cheaper and easier.

FULL STORY
__________________________________________________________________

Researchers have developed ultra-light tattoo electrodes that are
hardly noticeable on the skin and make long-term measurements of brain
activity cheaper and easier.

In 2015 Francesco Greco, head of the Laboratory of Applied Materials
for Printed and Soft electronics (LAMPSe) at the Institute of Solid
State Physics at Graz University of Technology, developed so-called
"tattoo electrodes" together with Italian scientists. These are
conductive polymers that are printed using an inkjet printer on
standard tattoo paper and then stuck to the skin like transfers to
measure heart or muscle activity.

This type of electrode, optimised in 2018, opened up completely new
paths in electrophysiological examinations, such as electrocardiography
(ECG) or electromyography (EMG). Thanks to a thickness of 700 to 800
nanometres -- that is about 100 times thinner than a human hair -- the
tattoos adapt to uneven skin and are hardly noticeable on the body.
Moreover, the "tattoos" are dry electrodes; in contrast to gel
electrodes, they work without a liquid interface and cannot dry out.
They are excellently suited for long-term measurements. Even hairs
growing through the tattoo do not interfere with the signal recording.

New generation of tattoo electrodes

Building on this pioneering achievement, Greco, together with Esma
Ismailova (Department of Bioelectronics, École Nationale Supérieure des
Mines de Saint-Étienne, France) and Laura Ferrari (The BioRobotics
Institute, Scuola Superiore Sant'Anna, Italy), has now achieved a
further milestone in the measurement of bioelectrical signals: the
group has modified the tattoo electrodes in such a way that they can
also be used in electroencephalography (EEG) -- i.e. to measure brain
activity.

To do this, the researchers used the same approach as in 2018, i.e.
inkjet printing of conductive polymer on tattoo paper. The composition
and thickness of the transfer paper and conductive polymer have been
optimized to achieve an even better connection between the tattoo
electrode and the skin and to record the EEG signals with maximum
quality, because: "Brain waves are in the low frequency range and EEG
signals have a very low amplitude. They are much more difficult to
capture in high quality than EMG or ECG signals," explains Laura
Ferrari, who worked on this project during her PhD and is now a postdoc
researcher in France.

Tests under real clinical conditions have shown that the EEG
measurement with the optimized tattoos is as successful as with
conventional EEG electrodes. "Due to inkjet printing and the
commercially available substrates, however, our tattoos are
significantly less expensive than current EEG electrodes and also offer
more advantages in terms of wearing comfort and long-term measurements
in direct comparison," says Greco.

First ever MEG-compatible dry electrodes

The new tattoo electrodes are the very first dry electrode type that is
suitable for long-term EEG measurements and at the same time compatible
with magneto-encephalography (MEG). MEG is a well-established method
for monitoring brain activity, for which so far only so-called "wet
electrodes" can be used. Such electrodes work on the basis of
electrolyte, gel or an electrode paste, and thus dry out quickly and
are unsuitable for long-term measurements. The new generation of tattoo
electrodes consists exclusively of conductive polymers, i.e. it does
not contain any metals which can be problematic for MEG examinations,
and is printed exclusively with inkjet. "With our method, we produce
the perfect MEG-compatible electrode while reducing costs and
production time," says Greco happily. The TU Graz researcher is
currently spinning ideas on how this technology can be used in clinics
and in neuroengineering as well as in the field of brain computer
interfaces.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Graz University of Technology. Original
written by Christoph Pelzl. Note: Content may be edited for style and
length.
__________________________________________________________________

Journal Reference:
1. Laura M. Ferrari, Usein Ismailov, Jean-Michel Badier, Francesco
Greco, Esma Ismailova. Conducting polymer tattoo electrodes in
clinical electro- and magneto-encephalography. npj Flexible
Electronics, 2020; 4 (1) DOI: [19]10.1038/s41528-020-0067-z
__________________________________________________________________

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Radioactive period following nuclear bomb tests changed rainfall patterns thousands of miles from the detonation sites

Date:
May 13, 2020

Source:
University of Reading

Summary:
Historic records from weather stations show that rainfall
patterns in Scotland were affected by charge in the atmosphere
released by radiation from nuclear bomb tests carried out in the
1950s and '60s.

FULL STORY
__________________________________________________________________

Nuclear bomb tests during the Cold War may have changed rainfall
patterns thousands of miles from the detonation sites, new research has
revealed.

Scientists at the University of Reading have researched how the
electric charge released by radiation from the test detonations,
carried out predominantly by the US and Soviet Union in the 1950s and
1960s, affected rainclouds at the time.

The study, published in Physical Review Letters, used historic records
between 1962-64 from a research station in Scotland. Scientists
compared days with high and low radioactively-generated charge, finding
that clouds were visibly thicker, and there was 24% more rain on
average on the days with more radioactivity.

Professor Giles Harrison, lead author and Professor of Atmospheric
Physics at the University of Reading, said: "By studying the
radioactivity released from Cold War weapons tests, scientists at the
time learnt about atmospheric circulation patterns. We have now reused
this data to examine the effect on rainfall.

"The politically charged atmosphere of the Cold War led to a nuclear
arms race and worldwide anxiety. Decades later, that global cloud has
yielded a silver lining, in giving us a unique way to study how
electric charge affects rain."

It has long been thought that electric charge modifies how water
droplets in clouds collide and combine, potentially affecting the size
of droplets and influencing rainfall, but this is difficult to observe
in the atmosphere. By combining the bomb test data with weather
records, the scientists were able to retrospectively investigate this.

Through learning more about how charge affects non-thunderstorm clouds,
it is thought that scientists will now have a better understanding of
important weather processes.

The race to develop nuclear weapons was a key feature of the Cold War,
as the world's superpowers sought to demonstrate their military
capabilities during heightened tensions following the Second World War.

Although detonations were carried out in remote parts of the world,
such as the Nevada Desert in the US, and on Pacific and Arctic islands,
radioactive pollution spread widely throughout the atmosphere.
Radioactivity ionises the air, releasing electric charge.

The researchers, from the Universities of Reading, Bath and Bristol,
studied records from well-equipped Met Office research weather stations
at Kew near London and Lerwick in the Shetland Isles.

Located 300 miles north west of Scotland, the Shetland site was
relatively unaffected by other sources of anthropogenic pollution. This
made it well suited as a test site to observe rainfall effects which,
although likely to have occurred elsewhere too, would be much more
difficult to detect.

Atmospheric electricity is most easily measured on fine days, so the
Kew measurements were used to identify nearly 150 days where there was
high or low charge generation over the UK while it was cloudy in
Lerwick. The Shetland rainfall on these days showed differences which
vanished after the major radioactivity episode was over.

The findings may be helpful for cloud-related geoengineering research,
which is exploring how electric charge could influence rain, relieve
droughts or prevent floods, without the use of chemicals.

Professor Harrison is leading a project investigating electrical
effects on dusts and clouds in the United Arab Emirates, as part of
their national programme in Rain Enhancement Science. These new
findings will help to show the typical charges possible in natural
non-thunderstorm clouds.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Reading. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Harrison, G., Nicoll, K., Ambaum, M., Marlton, G., Aplin, K.,
Lockwood, M. Precipitation modification by ionisation. Physical
Review Letters, 2020 DOI: [19]10.1103/PhysRevLett.124.198701
__________________________________________________________________

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hydride complexes

Date:
May 13, 2020

Source:
Tohoku University

Summary:
There is currently a strong demand to replace organic liquid
electrolytes used in conventional rechargeable batteries, with
solid-state ionic conductors which will enable the batteries to
be safer and have higher energy density.

FULL STORY
__________________________________________________________________

There is currently a strong demand to replace organic liquid
electrolytes used in conventional rechargeable batteries, with
solid-state ionic conductors which will enable the batteries to be
safer and have higher energy density.

To that end, much effort has been devoted to finding materials with
superior ionic conductivities. Among the most promising, are
solid-state ionic conductors that contain polyanions such as
B[12]H[12]^2-. They constitute a particular class of materials due to
their unique transport behavior, which has the polyanions rotating at
an elevated temperature, thereby greatly promoting cation
conductivities.

However, a major drawback is the high temperature (=energy) required to
activate the rotation, which conversely means low conductivities at
room temperature.

To address that problem, a research group at Tohoku University, led by
Associate Professor Shigeyuki Takagi and Professor Shin-ichi Orimo, has
established a new principle for room-temperature superionic conduction.
Its findings were recently published in Applied Physics Letters.

The research group was able to reduce the activation temperature by
using transition metal hydride complexes as a new class of rotatable
polyanions, wherein hydrogen is the sole ligand species, covalently
binding to single transition metals. Unlike in B[12]H[12]^2-
polyanions, the rotation of transition metal hydride complexes only
requires displacements of highly mobile hydrogen and can therefore be
expected to occur with low activation energy.

The group then studied the dynamics of transition metal hydride
complexes in several existing hydrides, and found them reoriented -- as
if rotating by repeating small deformations -- even at room
temperature.

This kind of motion is known as "pseudorotation," and is rarely
observed in solid matter. Due to the small displacements of hydrogen
atoms, the activation energy of the pseudorotation is relatively low --
more than 40 times lower than what's reportedly needed for the rotation
of B[12]H[12]^2-.

As a result of a cation conduction being promoted from a low
temperature region by pseudorotation, the lithium ion conductivity in
Li[5]MoH[11] containing MoH[9]^3-, for example, can reach 79 mS cm^-1
at room temperature. This is more than three times the world record of
room-temperature lithium ion conductivity reported so far. This
suggests that an all-solid-state lithium ion battery with shorter
charging time at room temperature can be realised.

The discovered mechanism is quite general and would be useful in
lowering the temperature required to activate the rotation of
polyanions. This may positively contribute towards finding compositions
that are amenable to room-temperature superionic conductors.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Tohoku University. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Shigeyuki Takagi, Tamio Ikeshoji, Toyoto Sato, Shin-ichi Orimo.
Pseudorotating hydride complexes with high hydrogen coordination: A
class of rotatable polyanions in solid matter. Applied Physics
Letters, 2020; 116 (17): 173901 DOI: [19]10.1063/5.0002992
__________________________________________________________________

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Date:
May 14, 2020

Source:
DOE/Lawrence Berkeley National Laboratory

Summary:
A new study revealed hundreds of new strong gravitational
lensing candidates based on a deep dive into data. The study
benefited from the winning machine-learning algorithm in an
international science competition.

FULL STORY
__________________________________________________________________

Like crystal balls for the universe's deeper mysteries, galaxies and
other massive space objects can serve as lenses to more distant objects
and phenomena along the same path, bending light in revelatory ways.

Gravitational lensing was first theorized by Albert Einstein more than
100 years ago to describe how light bends when it travels past massive
objects like galaxies and galaxy clusters.

These lensing effects are typically described as weak or strong, and
the strength of a lens relates to an object's position and mass and
distance from the light source that is lensed. Strong lenses can have
100 billion times more mass than our sun, causing light from more
distant objects in the same path to magnify and split, for example,
into multiple images, or to appear as dramatic arcs or rings.

The major limitation of strong gravitational lenses has been their
scarcity, with only several hundred confirmed since the first
observation in 1979, but that's changing ... and fast.

A new study by an international team of scientists revealed 335 new
strong lensing candidates based on a deep dive into data collected for
a U.S. Department of Energy-supported telescope project in Arizona
called the Dark Energy Spectroscopic Instrument (DESI). The study,
published May 7 in The Astrophysical Journal, benefited from the
winning machine-learning algorithm in an international science
competition.

"Finding these objects is like finding telescopes that are the size of
a galaxy," said David Schlegel, a senior scientist in Lawrence Berkeley
National Laboratory's (Berkeley Lab's) Physics Division who
participated in the study. "They're powerful probes of dark matter and
dark energy."

These newly discovered gravitational lens candidates could provide
specific markers for precisely measuring distances to galaxies in the
ancient universe if supernovae are observed and precisely tracked and
measured via these lenses, for example.

Strong lenses also provide a powerful window into the unseen universe
of dark matter, which makes up about 85 percent of the matter in the
universe, as most of the mass responsible for lensing effects is
thought to be dark matter. Dark matter and the accelerating expansion
of the universe, driven by dark energy, are among the biggest mysteries
that physicists are working to solve.

In the latest study, researchers enlisted Cori, a supercomputer at
Berkeley Lab's National Energy Research Scientific Computing Center
(NERSC), to automatically compare imaging data from the Dark Energy
Camera Legacy Survey (DECaLS) -- one of three surveys conducted in
preparation for DESI -- with a training sample of 423 known lenses and
9,451 non-lenses.

The researchers grouped the candidate strong lenses into three
categories based on the likelihood that they are, in fact, lenses:
Grade A for the 60 candidates that are most likely to be lenses, Grade
B for the 105 candidates with less pronounced features, and Grade C for
the 176 candidate lenses that have fainter and smaller lensing features
than those in the other two categories.

Xiaosheng Huang, the study's lead author, noted that the team already
succeeded in winning time on the Hubble Space Telescope to confirm some
of the most promising lensing candidates revealed in the study, with
observing time on the Hubble that began in late 2019.

"The Hubble Space Telescope can see the fine details without the
blurring effects of Earth's atmosphere," Huang said.

The lens candidates were identified with the assistance of a neural
network, which is a form of artificial intelligence in which the
computer program is trained to gradually improve its image-matching
over time to provide an increasing success rate in identifying lenses.
Computerized neural networks are inspired by the biological network of
neurons in the human brain.

"It takes hours to train the neural network," Huang said. "There is a
very sophisticated fitting model of 'What is a lens?' and 'What is not
a lens?'"

There was some painstaking manual analysis of lensing images to help
pick the best images to train the network from tens of thousands of
images, Huang noted. He recalled one Saturday during which he sat down
with student researchers for the entire day to pore over tens of
thousands of images to develop sample lists of lenses and non-lenses.

"We didn't just select these at random," Huang said. "We had to augment
this set with hand-selected examples that look like lenses but are not
lenses," for example, "and we selected those that could be potentially
confusing."

Student involvement was key in the study, he added. "The students
worked diligently on this project and solved many tough problems, all
while taking a full load of classes," he said. One of the students who
worked on the study, Christopher Storfer, was later selected to
participate in the DOE Science Undergraduate Laboratory Internship
(SULI) program at Berkeley Lab.

Researchers have already improved upon the algorithm that was used in
the latest study to speed up the identification of possible lenses.
While an estimated 1 in 10,000 galaxies acts as a lens, the neural
network can eliminate most of the non-lenses. "Rather than going
through 10,000 images to find one, now we have just a few tens," he
said.

The neural network was originally developed for The Strong
Gravitational Lens Finding Challenge, a programming competition that
ran from November 2016 to February 2017 that motivated the development
of automated tools for finding strong lenses.

With a growing body of observational data, and new telescope projects
like DESI and the Large Synoptic Survey Telescope (LSST) that is now
scheduled to start up in 2023, there is heated competition to mine this
data using sophisticated artificial intelligence tools, Schlegel said.

"That competition is good," he said. A team based in Australia, for
example, also found many new lensing candidates using a different
approach. "About 40 percent of what they found we didn't," and likewise
the study that Schlegel participated in found many lensing candidates
that the other team hadn't.

Huang said the team has expanded its search for lenses in other sources
of sky-imaging data, and the team is also considering whether to plug
into a broader set of computing resources to expedite the hunt.

"The goal for us is to reach 1,000" new lensing candidates, Schlegel
said.

NERSC is a DOE Office of Science User Facility.

Study participants included researchers from the University of San
Francisco, Berkeley Lab, the National Optical Astronomy Observatory,
Siena College, the University of Wyoming, the University of Arizona,
the University of Toronto and the Perimeter Institute for Theoretical
Physics in Canada, and Université Paris-Saclay in France.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]DOE/Lawrence Berkeley National
Laboratory. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. X. Huang, C. Storfer, V. Ravi, A. Pilon, M. Domingo, D. J.
Schlegel, S. Bailey, A. Dey, R. R. Gupta, D. Herrera, S. Juneau, M.
Landriau, D. Lang, A. Meisner, J. Moustakas, A. D. Myers, E. F.
Schlafly, F. Valdes, B. A. Weaver, J. Yang, C. Yèche. Finding
Strong Gravitational Lenses in the DESI DECam Legacy Survey. The
Astrophysical Journal, 2020; 894 (1): 78 DOI:
[19]10.3847/1538-4357/ab7ffb
__________________________________________________________________

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First scientific result by the new spectrograph on the Subaru telescope

Date:
May 14, 2020

Source:
National Institutes of Natural Sciences

Summary:
Astronomers have determined that the Earth-like planets of the
TRAPPIST-1 system are not significantly misaligned with the
rotation of the star. This is an important result for
understanding the evolution of planetary systems around very
low-mass stars in general, and in particular the history of the
TRAPPIST-1 planets including the ones near the habitable zone.

FULL STORY
__________________________________________________________________

Astronomers using the Subaru Telescope have determined that the
Earth-like planets of the TRAPPIST-1 system are not significantly
misaligned with the rotation of the star. This is an important result
for understanding the evolution of planetary systems around very
low-mass stars in general, and in particular the history of the
TRAPPIST-1 planets including the ones near the habitable zone.

Stars like the Sun are not static, but rotate about an axis. This
rotation is most noticeable when there are features like sunspots on
the surface of the star. In the Solar System, the orbits of all of the
planets are aligned to within 6 degrees with the Sun's rotation. In the
past it was assumed that planetary orbits would be aligned with the
rotation of the star, but there are now many known examples of
exoplanet systems where the planetary orbits are strongly misaligned
with the central star's rotation. This raises the question: can
planetary systems form out of alignment, or did the observed misaligned
systems start out aligned and were later thrown out of alignment by
some perturbation? The TRAPPIST-1 system has attracted attention
because it has three small rocky planets located in or near the
habitable zone where liquid water can exist. The central star is a very
low-mass and cool star, called an M dwarf, and those planets are
situated very close to the central star. Therefore, this planetary
system is very different from our Solar System. Determining the history
of this system is important because it could help determine if any of
the potentially habitable planets are actually inhabitable. But it is
also an interesting system because it lacks any nearby objects which
could have perturbed the orbits of the planets, meaning that the orbits
should still be located close to where the planets first formed. This
gives astronomers a chance to investigate the primordial conditions of
the system.

Because stars rotate, the side rotating into view has a relative
velocity towards the viewer, while the side rotating out of view has a
relative velocity away from the viewer. If a planet transits, passes
between the star and the Earth and blocks a small portion of the light
from the star, it is possible to tell which edge of the star the planet
blocks first. This phenomenon is called the Rossiter-McLaughlin effect.
Using this method, it is possible to measure the misalignment between
the planetary orbit and the star's rotation. However, until now those
observations have been limited to large planets such as Jupiter-like or
Neptune-like ones.

A team of researchers, including members from the Tokyo Institute of
Technology and the Astrobiology Center in Japan, observed TRAPPIST-1
with the Subaru Telescope to look for misalignment between the
planetary orbits and the star. The team took advantage of a chance on
August 31, 2018, when three of the exoplanets orbiting TRAPPIST-1
transited in front of the star in a single night. Two of the three were
rocky planets near the habitable zone. Since low-mass stars are
generally faint, it had been impossible to probe the stellar obliquity
(spin-orbit angle) for TRAPPIST-1. But thanks to the light gathering
power of the Subaru Telescope and high spectral resolution of the new
infrared spectrograph IRD, the team was able to measure the obliquity.
They found that the obliquity was low, close to zero. This is the first
measurement of the stellar obliquity for a very low-mass star like
TRAPPIST-1 and also the first Rossiter-McLaughlin measurement for
planets in the habitable zone.

However the leader of the team, Teruyuki Hirano at the Tokyo Institute
of Technology, cautions, "The data suggest alignment of the stellar
spin with the planetary orbital axes, but the precision of the
measurements was not good enough to completely rule out a small
spin-orbit misalignment. Nonetheless, this is the first detection of
the effect with Earth-like planets and more work will better
characterize this remarkable exoplanet system."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]National Institutes of Natural Sciences.
Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Teruyuki Hirano, Eric Gaidos, Joshua N. Winn, Fei Dai, Akihiko
Fukui, Masayuki Kuzuhara, Takayuki Kotani, Motohide Tamura, Maria
Hjorth, Simon Albrecht, Daniel Huber, Emeline Bolmont, Hiroki
Harakawa, Klaus Hodapp, Masato Ishizuka, Shane Jacobson, Mihoko
Konishi, Tomoyuki Kudo, Takashi Kurokawa, Jun Nishikawa, Masashi
Omiya, Takuma Serizawa, Akitoshi Ueda, Lauren M. Weiss. Evidence
for Spin–Orbit Alignment in the TRAPPIST-1 System. The
Astrophysical Journal, 2020; 890 (2): L27 DOI:
[19]10.3847/2041-8213/ab74dc
__________________________________________________________________

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Date:
May 14, 2020

Source:
University of Hawaii at Manoa

Summary:
Researchers revealed the largest and hottest shield volcano on
Earth. A team of volcanologists and ocean explorers used several
lines of evidence to determine P?h?honu, a volcano within the
Papah?naumoku?kea Marine National Monument now holds this
distinction.

FULL STORY
__________________________________________________________________

In a recently published study, researchers from the University of
Hawai'i at Mānoa School of Ocean and Earth Science and Technology
revealed the largest and hottest shield volcano on Earth. A team of
volcanologists and ocean explorers used several lines of evidence to
determine Pūhāhonu, a volcano within the Papahānaumokuākea Marine
National Monument now holds this distinction.

Geoscientists and the public have long thought Mauna Loa, a
culturally-significant and active shield volcano on the Big Island of
Hawai'i, was the largest volcano in the world. However, after surveying
the ocean floor along the mostly submarine Hawaiian leeward volcano
chain, chemically analyzing rocks in the UH Mānoa rock collection, and
modeling the results of these studies, the research team came to a new
conclusion. Pūhāhonu, meaning 'turtle rising for breath' in Hawaiian,
is nearly twice as big as Mauna Loa.

"It has been proposed that hotspots that produce volcano chains like
Hawai'i undergo progressive cooling over 1-2 million years and then
die," said Michael Garcia, lead author of the study and retired
professor of Earth Sciences at SOEST. "However, we have learned from
this study that hotspots can undergo pulses of melt production. A small
pulse created the Midway cluster of now extinct volcanoes and another,
much bigger one created Pūhāhonu. This will rewrite the textbooks on
how mantle plumes work."

In 1974, Pūhāhonu (then called Gardner Pinnacles) was suspected as the
largest Hawaiian volcano based on very limited survey data. Subsequent
studies of the Hawaiian Islands concluded that Mauna Loa was the
largest volcano but they included the base of the volcano that is below
sea level that was not considered in the 1974 study. The new
comprehensive surveying and modeling, using methods similar to those
used for Mauna Loa show that Pūhāhonu is the largest.

This study highlights Hawaiian volcanoes, not only now but for millions
of years, have been erupting some of the hottest magma on Earth. This
work also draws attention to an infrequently visited part of the state
of Hawai'i that has ecological, historical and cultural importance.

"We are sharing with the science community and the public that we
should be calling this volcano by the name the Hawaiians have given to
it, rather than the western name for the two rocky small islands that
are the only above sea level remnants of this once majestic volcano,"
said Garcia.

This work was funded by the National Science Foundation, Schmidt Ocean
Institute and the University of Hawai'i.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Hawaii at Manoa. Original
written by Marcie Grabowski. Note: Content may be edited for style and
length.
__________________________________________________________________

Journal Reference:
1. Michael O. Garcia, Jonathan P. Tree, Paul Wessel, John R. Smith.
Pūhāhonu: Earth's biggest and hottest shield volcano. Earth and
Planetary Science Letters, 2020; 542: 116296 DOI:
[19]10.1016/j.epsl.2020.116296
__________________________________________________________________

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Study reveals how wavelike plasmons could power up a new class of sensing and photochemical technologies at the nanoscale

Date:
May 14, 2020

Source:
DOE/Lawrence Berkeley National Laboratory

Summary:
A team of researchers has observed unusually long-lived wavelike
electrons called 'plasmons' in a new class of electronically
conducting material. Plasmons are very important for determining
the optical and electronic properties of metals for the
development of new sensors and communication devices.

FULL STORY
__________________________________________________________________

Wavelike, collective oscillations of electrons known as "plasmons" are
very important for determining the optical and electronic properties of
metals.

In atomically thin 2D materials, plasmons have an energy that is more
useful for applications, including sensors and communication devices,
than plasmons found in bulk metals. But determining how long plasmons
live and whether their energy and other properties can be controlled at
the nanoscale (billionths of a meter) has eluded many.

Now, as reported in the journal Nature Communications, a team of
researchers co-led by the Department of Energy's Lawrence Berkeley
National Laboratory (Berkeley Lab) -- with support from the Department
of Energy's Center for Computational Study of Excited-State Phenomena
in Energy Materials (C2SEPEM) -- has observed long-lived plasmons in a
new class of conducting transition metal dichalcogenide (TMD) called
"quasi 2D crystals."

To understand how plasmons operate in quasi 2D crystals, the
researchers characterized the properties of both nonconductive
electrons as well as conductive electrons in a monolayer of the TMD
tantalum disulfide. Previous studies only looked at conducting
electrons. "We discovered that it was very important to carefully
include all the interactions between both types of electrons," said
C2SEPEM Director Steven Louie, who led the study. Louie also holds
titles as senior faculty scientist in the Materials Sciences Division
at Berkeley Lab and professor of physics at UC Berkeley.

The researchers developed sophisticated new algorithms to compute the
material's electronic properties, including plasmon oscillations with
long wavelengths, "as this was a bottleneck with previous computational
approaches," said lead author Felipe da Jornada, who was a postdoctoral
researcher in Berkeley Lab's Materials Sciences Division at the time of
the study. Jornada is currently an assistant professor in materials
science and engineering at Stanford University.

To the researchers' surprise, the results from calculations performed
by the Cori supercomputer at Berkeley Lab's National Energy Research
Scientific Computing Center (NERSC) revealed that plasmons in quasi 2D
TMDs are much more stable -- for as long as approximately 2
picoseconds, or 2 trillionths of a second -- than previously thought.

Their findings also suggest that plasmons generated by quasi 2D TMDs
could enhance the intensity of light by more than 10 million times,
opening the door for renewable chemistry (chemical reactions triggered
by light), or the engineering of electronic materials that can be
controlled by light.

In future studies, the researchers plan to investigate how to harness
the highly energetic electrons released by such plasmons upon decay,
and if they can be used to catalyze chemical reactions.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]DOE/Lawrence Berkeley National
Laboratory. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Felipe H. da Jornada, Lede Xian, Angel Rubio, Steven G. Louie.
Universal slow plasmons and giant field enhancement in atomically
thin quasi-two-dimensional metals. Nature Communications, 2020; 11
(1) DOI: [19]10.1038/s41467-020-14826-8
__________________________________________________________________

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Date:
May 14, 2020

Source:
Tohoku University

Summary:
Researchers have developed a new multi-beam method for
conducting CT scans that improve image quality whilst
drastically cutting the required time to one millisecond.

FULL STORY
__________________________________________________________________

Many will undergo a CT scan at some point in their lifetime -- being
slid in and out of a tunnel as a large machine rotates around. X-ray
computed tomography, better known by its acronym CT, is a widely used
method of obtaining cross-sectional images of objects.

Now a research team -- led by Tohoku University Professor, Wataru
Yashiro -- has developed a new method using intense synchrotron
radiation that produces higher quality images within milliseconds.

High-speed, high-resolution X-ray CT is currently possible using
intense synchrotron radiation. However, this requires samples to be
rotated at high speed to obtain images from many directions. This would
make CT scans more akin to a rollercoaster ride!

Extreme rotation also makes controlling the temperature or atmosphere
of the sample impossible.

Nevertheless, the research team solved this conundrum by creating an
optical system that splits single synchrotron X-ray beams into many.
These beams then shine onto the sample from different directions at the
same time; thus, negating the need to rotate the sample.

This "multi-beam" method is no easy task since the direction of X-rays
cannot be easily changed. Unlike visible light, X-rays interact with
matters weakly, making it difficult to utilize mirrors and prisms to
change the path of the beams.

To overcome this, the research team used micro-fabrication techniques
to create uniquely shaped crystals. These crystals were then bent in
the shape of a hyperbola. By combining three rows of crystals, the
multi-beam optics were able to cover an angle of ±70°.

Carrying out their experiments at the SPring-8 synchrotron radiation
facility, the research team took advantage of a cutting-edge
compressed-sensing algorithm that needs only a few dozen projection
images for image reconstruction.

"The invention makes 3-D observations of living beings and liquid
samples within milliseconds possible" exclaimed Professor Yashiro. "Its
possible application is wide-spread, from fundamental material science
to life sciences to industry," added Yashiro.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Tohoku University. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Wolfgang Voegeli, Kentaro Kajiwara, Hiroyuki Kudo, Tetsuroh
Shirasawa, Xiaoyu Liang, Wataru Yashiro. Multibeam x-ray optical
system for high-speed tomography. Optica, 2020; 7 (5): 514 DOI:
[19]10.1364/OPTICA.384804
__________________________________________________________________

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Date:
May 14, 2020

Source:
University of Washington

Summary:
Prior to the COVID-19 pandemic, in cities where bike-share
systems have been introduced, bike commuting increased by 20%,
according to a new study.

FULL STORY
__________________________________________________________________

In the past couple of years, if you lived in a major, or even mid-sized
city, you were likely familiar with bike-share bikes.

Whether propped against a tree, strewn along the sidewalk or standing
"docked" at a station, the often brightly colored bikes with whimsical
company names promised a ready means to get from Point A to Point B.

But one person's spontaneous ride is another person's commute to work.
Prior to the COVID-19 pandemic, in cities where bike-share systems have
been introduced, bike commuting increased by 20%, said Dafeng Xu, an
assistant professor in the University of Washington's Evans School of
Public Policy & Governance. Xu studied U.S. cities with and without
bike-share systems, using Census and company data to analyze how
commuting patterns change when bike shares become available.

"This study shows that bike-share systems can drive a population to
commute by bike," said Xu, whose study was published May 11 in the
Journal of Policy Analysis and Management.

Bike-share systems, common in cities in Europe and Asia, were launched
in four U.S. cities in 2010 and as of 2016 had grown to more than 50.
Not all systems have been successful: Convenience -- how easy it is to
find and rent a bike -- is the key. In Seattle, for example, a
city-owned bike-share program failed in 2017 due largely to a limited
number of bikes and a lack of infrastructure, but private companies in
the same market thrived prior to the pandemic.

[Around the world, cities have enacted mobility restrictions during the
coronavirus outbreak. The responses of bike-share companies, and
bike-share usage, have varied by community.]

Among other interests in transportation and immigration policy, Xu
researches the effects of bicycling on the environment and human
health, and on the ways bike-share systems can play a role by expanding
access to cycling.

"In general, biking is good and healthy, and it means less pollution
and traffic, but it can be expensive, and people worry about their
bikes being stolen, things like that," Xu said. "Bike share solves some
of these problems, because people don't need to worry about the cost
and theft."

For this study, Xu sorted through nine years of demographic and commute
statistics from the American Community Survey, a detailed, annual
report by the Census Bureau. He then examined bike-share company data
(through the National Association of City Transportation Officials)
from 38 cities with systems, focusing on trips logged during morning
and afternoon rush hours. By comparing the number, location and time of
work-related bike commutes from Census data against bike-share company
records of trips logged, both before and after the launch of bike
shares, Xu was able to estimate the use of bike shares for commute
trips.

Xu found that in both bike-share and non-bike-share cities, the rate of
bike commuting increased, while car commuting decreased, from
2008-2016. However, the rate of bike commuting -- and the use of public
transportation -- was significantly greater in bike-share cities.

For example, in bike-share cities in 2008, roughly 66% of commuters
drove to work, about 1% biked, and 22% took transit. That compared to
non-bike-share cities, where about 88% of commuters drove, fewer than
1% biked, and 4% took transit.

By 2016 -- after many bike-share systems had launched -- car commuting
had fallen to 59% in bike-share cities, while bike commuting had
climbed to 1.7% and transit to 26%. Commuting by car in non-bike-share
cities had slipped to 83% in 2016, while bike commuting had grown to
1%, and transit to 6%.

Nationwide, 0.6% of commuters bike to work, according to an American
Community Survey report in 2017.

In general, cities with larger bike-share systems also experienced
sharper increases in bicycle commuting, Xu said.

"This is not surprising: A large bike-share system means a higher
density of public bicycles and is thus more accessible by commuters,"
he said. "In contrast, sadly, Seattle's Pronto struggled to attract
commuters and was finally doomed only after three years of operation
partially due to its relatively small size."

In his paper, Xu points to Chicago, which operates a municipally owned
bike-share system called Divvy. Prior to Divvy's launch in 2013, 1.5%
of commuters biked to work, Xu said, but afterward, that rate grew to
2%.

The trends held, he said, even when controlling for a city's expansion
of protected bike lanes -- another significant factor in whether people
choose to bike to work, according to other research.

Overall, the numbers before COVID-19 were promising, Xu said. The
numbers could grow, he said, if communities and bike-share companies
make changes that can boost the appeal of bike commuting: adding bike
lanes to city streets, expanding programs to outlying communities, or
increasing the allowable rental time. Many bike shares, for instance,
last only up to a half-hour before a user has to pay for a new trip.

Xu is also the author of a previous paper analyzed the impact of
bike-share systems on obesity rates.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Washington. Original
written by Kim Eckart. Note: Content may be edited for style and
length.
__________________________________________________________________

Journal References:
1. Dafeng Xu. Free Wheel, Free Will! The Effects of Bikeshare Systems
on Urban Commuting Patterns in the U.S. . Journal of Policy
Analysis and Management, 2020; DOI: [19]10.1002/pam.22216
2. Dafeng Xu. Burn Calories, Not Fuel! The effects of bikeshare
programs on obesity rates. Transportation Research Part D:
Transport and Environment, 2019; 67: 89 DOI:
[20]10.1016/j.trd.2018.11.002
__________________________________________________________________

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states

Date:
May 15, 2020

Source:
DOE/SLAC National Accelerator Laboratory

Summary:
Until now, electron spins and orbitals were thought to go hand
in hand in a class of materials that's the cornerstone of modern
information technology; you couldn't quickly change one without
changing the other. But a new study shows that a pulse of laser
light can dramatically change the spin state of one important
class of materials while leaving its orbital state intact.

FULL STORY
__________________________________________________________________

In designing electronic devices, scientists look for ways to manipulate
and control three basic properties of electrons: their charge; their
spin states, which give rise to magnetism; and the shapes of the fuzzy
clouds they form around the nuclei of atoms, which are known as
orbitals.

Until now, electron spins and orbitals were thought to go hand in hand
in a class of materials that's the cornerstone of modern information
technology; you couldn't quickly change one without changing the other.
But a study at the Department of Energy's SLAC National Accelerator
Laboratory shows that a pulse of laser light can dramatically change
the spin state of one important class of materials while leaving its
orbital state intact.

The results suggest a new path for making a future generation of logic
and memory devices based on "orbitronics," said Lingjia Shen, a SLAC
research associate and one of the lead researchers for the study.

"What we're seeing in this system is the complete opposite of what
people have seen in the past," Shen said. "It raises the possibility
that we could control a material's spin and orbital states separately,
and use variations in the shapes of orbitals as the 0s and 1s needed to
make computations and store information in computer memories."

The international research team, led by Joshua Turner, a SLAC staff
scientist and investigator with the Stanford Institute for Materials
and Energy Science (SIMES), reported their results this week in
Physical Review B Rapid Communications.

An intriguing, complex material

The material the team studied was a manganese oxide-based quantum
material known as NSMO, which comes in extremely thin crystalline
layers. It's been around for three decades and is used in devices where
information is stored by using a magnetic field to switch from one
electron spin state to another, a method known as spintronics. NSMO is
also considered a promising candidate for making future computers and
memory storage devices based on skyrmions, tiny particle-like vortexes
created by the magnetic fields of spinning electrons.

But this material is also very complex, said Yoshinori Tokura, director
of the RIKEN Center for Emergent Matter Science in Japan, who was also
involved in the study.

"Unlike semiconductors and other familiar materials, NSMO is a quantum
material whose electrons behave in a cooperative, or correlated,
manner, rather than independently as they usually do," he said. "This
makes it hard to control one aspect of the electrons' behavior without
affecting all the others."

One common way to investigate this type of material is to hit it with
laser light to see how its electronic states respond to an injection of
energy. That's what the research team did here. They observed the
material's response with X-ray laser pulses from SLAC's Linac Coherent
Light Source (LCLS).

One melts, the other doesn't

What they expected to see was that orderly patterns of electron spins
and orbitals in the material would be thrown into total disarray, or
"melted," as they absorbed pulses of near-infrared laser light.

But to their surprise, only the spin patterns melted, while the orbital
patterns stayed intact, Turner said. The normal coupling between the
spin and orbital states had been completely broken, he said, which is a
challenging thing to do in this type of correlated material and had not
been observed before.

Tokura said, "Usually only a tiny application of photoexcitation
destroys everything. Here, they were able to keep the electron state
that is most important for future devices -- the orbital state --
undamaged. This is a nice new addition to the science of orbitronics
and correlated electrons."

Much as electron spin states are switched in spintronics, electron
orbital states could be switched to provide a similar function. These
orbitronic devices could, in theory, operate 10,000 faster than
spintronic devices, Shen said.

Switching between two orbital states could be made possible by using
short bursts of terahertz radiation, rather than the magnetic fields
used today, he said: "Combining the two could achieve much better
device performance for future applications." The team is working on
ways to do that.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]DOE/SLAC National Accelerator Laboratory.
Original written by Glennda Chui. Note: Content may be edited for style
and length.
__________________________________________________________________

Journal Reference:
1. L. Shen, S. A. Mack, G. Dakovski, G. Coslovich, O. Krupin, M.
Hoffmann, S.-W. Huang, Y-D. Chuang, J. A. Johnson, S. Lieu, S.
Zohar, C. Ford, M. Kozina, W. Schlotter, M. P. Minitti, J. Fujioka,
R. Moore, W-S. Lee, Z. Hussain, Y. Tokura, P. Littlewood, J. J.
Turner. Decoupling spin-orbital correlations in a layered manganite
amidst ultrafast hybridized charge-transfer band excitation.
Physical Review B, 2020; 101 (20) DOI:
[19]10.1103/PhysRevB.101.201103
__________________________________________________________________

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Combined muscles and sensors made from soft materials allow for flexible
robots

Date:
May 15, 2020

Source:
University of Tokyo

Summary:
Robots can be made from soft materials, but the flexibility of
such robots is limited by the inclusion of rigid sensors
necessary for their control. Researchers created embedded
sensors, to replace rigid sensors, that offer the same
functionality but afford the robot greater flexibility. Soft
robots can be more adaptable and resilient than more traditional
rigid designs. The team used cutting-edge machine learning
techniques to create their design.

FULL STORY
__________________________________________________________________

Robots can be made from soft materials, but the flexibility of such
robots is limited by the inclusion of rigid sensors necessary for their
control. Researchers created embedded sensors, to replace rigid
sensors, that offer the same functionality but afford the robot greater
flexibility. Soft robots can be more adaptable and resilient than more
traditional rigid designs. The team used cutting-edge machine learning
techniques to create their design.

Automation is an increasingly important subject, and core to this
concept are the often paired fields of robotics and machine learning.
The relationship between machine learning and robotics is not just
limited to the behavioral control of robots, but is also important for
their design and core functions. A robot which operates in the real
world needs to understand its environment and itself in order to
navigate and perform tasks.

If the world was entirely predictable, then a robot would be fine
moving around without the need to learn anything new about its
environment. But reality is unpredictable and ever changing, so machine
learning helps robots adapt to unfamiliar situations. Although this is
theoretically true for all robots, it is especially important for
soft-bodied robots as the physical properties of these are
intrinsically less predictable than their rigid counterparts.

"Take for example a robot with pneumatic artificial muscles (PAM),
rubber and fiber-based fluid-driven systems which expand and contract
to move," said Associate Professor Kohei Nakajima from the Graduate
School of Information Science and Technology. "PAMs inherently suffer
random mechanical noise and hysteresis, which is essentially material
stress over time. Accurate laser-based monitors help maintain control
through feedback, but these rigid sensors restrict a robot's movement,
so we came up with something new."

Nakajima and his team thought if they could model a PAM in real time,
then they could maintain good control of it. However, given the
ever-changing nature of PAMs, this is not realistic with traditional
methods of mechanical modeling. So the team turned to a powerful and
established machine learning technique called reservoir computing. This
is where information about a system, in this case the PAM, is fed into
a special artificial neural network in real time, so the model is ever
changing and thus adapts to the environment.

"We found the electrical resistance of PAM material changes depending
on its shape during a contraction. So we pass this data to the network
so it can accurately report on the state of the PAM," said Nakajima.
"Ordinary rubber is an insulator, so we incorporated carbon into our
material to more easily read its varying resistance. We found the
system emulated the existing laser-displacement sensor with equally
high accuracy in a range of test conditions."

Thanks to this method, a new generation of soft robotic technology may
be possible. This could include robots that work with humans, for
example wearable rehabilitation devices or biomedical robots, as the
extra soft touch means interactions with them are gentle and safe.

"Our study suggests reservoir computing could be used in applications
besides robotics. Remote-sensing applications, which need real-time
information processed in a decentralized manner, could greatly
benefit," said Nakajima. "And other researchers who study neuromorphic
computing -- intelligent computer systems -- might also be able to
incorporate our ideas into their own work to improve the performance of
their systems."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Tokyo. Note: Content may be
edited for style and length.
__________________________________________________________________

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Date:
May 15, 2020

Source:
Kansas State University

Summary:
Researchers developed a computer simulation that revealed beef
supply chain vulnerabilities that need safeguarding -- a
realistic concern during the COVID-19 pandemic.

FULL STORY
__________________________________________________________________

An interdisciplinary team of Kansas State University researchers
developed a computer simulation that revealed beef supply chain
vulnerabilities that need safeguarding -- a realistic concern during
the COVID-19 pandemic.

Caterina Scoglio, professor, and Qihui Yang, doctoral student, both in
electrical and computer engineering, recently published "Developing an
agent-based model to simulate the beef cattle production and
transportation in southwest Kansas" in Physica A, an Elsevier journal
publication.

The paper describes a model of the beef production system and the
transportation industry, which are interdependent critical
infrastructures -- similar to the electrical grid and computer
technology. According to the model, disruptions in the cattle industry
-- especially in the beef packing plants -- will affect the
transportation industry and together cause great economic harm. The
disruptions modeled in the simulation share similarities with how the
packing plants have been affected during the COVID-19 pandemic.

"When we first started working on this project, there was a lot of
emphasis on studying critical infrastructures; especially ones that are
interdependent, meaning that they need to work together with other
critical infrastructures," Scoglio said. "The idea is if there is a
failure in one of the systems, it can propagate to the other system,
increasing the catastrophic effects."

The study included a variety of viewpoints to create a realistic and
integrated model of both systems. Co-authors on the paper include Don
Gruenbacher, associate professor and department head of electrical and
computer engineering; Jessica Heier Stamm, associate professor of
industrial and manufacturing systems engineering; Gary Brase, professor
of psychological sciences; Scott DeLoach, professor and department head
of computer science; and David Amrine, research director of the Beef
Cattle Institute.

The researchers used the model to evaluate which supply chain
components were more robust and which were not. They determined that
packing plants are the most vulnerable. Scoglio said that recent events
in the middle of the COVID-19 pandemic raise important issues about how
to safeguard the system.

"An important message is that after understanding the critical role of
these packers, we need to decide how we could protect both them and the
people who work there," Scoglio said. "While the plants are a critical
infrastructure and need to be protected, taking care of the health of
the workers is very important. How can we design a production process
that can be flexible and adaptable in an epidemic?"

According to the paper, the beef cattle industry contributes
approximately $8.9 billion to the Kansas economy and employs more than
42,000 people in the state. Since trucks are needed to move cattle, any
disruption in either cattle production or transportation almost
certainly would harm the regional economy, Scoglio said.

"Packers need to be considered as a critical point of a much longer
supply chain, which needs specific attention to make sure it will not
fail and can continue working," Scoglio said. "Beef packers are a
critical infrastructure in the United States."

The project was supported by the National Science Foundation and
focused on southwest Kansas, but the researchers acknowledge that
cattle come from outside the region and interruptions may have larger
national effects.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Kansas State University. Original written
by Stephanie Jacques. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Qihui Yang, Don Gruenbacher, Jessica L. Heier Stamm, Gary L. Brase,
Scott A. DeLoach, David E. Amrine, Caterina Scoglio. Developing an
agent-based model to simulate the beef cattle production and
transportation in southwest Kansas. Physica A: Statistical
Mechanics and its Applications, 2019; 526: 120856 DOI:
[19]10.1016/j.physa.2019.04.092
__________________________________________________________________

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Date:
May 15, 2020

Source:
European Synchrotron Radiation Facility

Summary:
Moisture is the main environmental factor that triggers the
degradation of the masterpiece The Scream (1910) by Edvard
Munch, according to new findings using a combination of in situ
non-invasive spectroscopic methods and synchrotron X-ray
techniques.

FULL STORY
__________________________________________________________________

Moisture is the main environmental factor that triggers the degradation
of the masterpiece The Scream (1910?) by Edvard Munch, according to the
finding of an international team of scientists led by the CNR (Italy),
using a combination of in situ non-invasive spectroscopic methods and
synchrotron X-ray techniques. After exploiting the capability of the
European mobile platform MOLAB in situ and non-invasively at the Munch
Museum in Oslo, the researchers came to the ESRF, the European
Synchrotron (Grenoble, France), the world's brightest X-ray source, to
carry out non-destructive experiments on micro-flakes originating from
one of the most well-known versions of The Scream. The findings could
help better preserve this masterpiece, which is seldom exhibited due to
its degradation. The study is published in Science Advances.

The Scream is among the most famous paintings of the modern era. The
now familiar image is interpreted as the ultimate representation of
anxiety and mental anguish. There are a number of versions of The
Scream, namely two paintings, two pastels, several lithographic prints
and a few drawings and sketches. The two most well-known versions are
the paintings that Edvard Munch created in 1893 and 1910. Each version
of The Scream is unique. Munch clearly experimented to find the exact
colours to represent his personal experience, mixing diverse binding
media (tempera, oil and pastel) with brilliant and bold synthetic
pigments to make 'screaming colours'. Unfortunately, the extensive use
of these new coloured materials poses a challenge for the long-term
preservation of Munch's artworks.

The version of the Scream (1910?) that belongs to the Munch Museum
(Oslo, Norway) clearly exhibits signs of degradation in different areas
where cadmium-sulfide-based pigments have been used: cadmium yellow
brushstrokes have turned to an off-white colour in the sunset cloudy
sky and in the neck area of the central figure. In the lake, a thickly
applied opaque cadmium yellow paint is flaking. Throughout its
existence, several elements have played a role in the deterioration of
the masterpiece: the yellow pigments used, the environmental conditions
and a theft in 2004, when the painting disappeared for two years.

Since the recovery of the painting after the theft, the masterpiece has
rarely been shown to the public. Instead, it is preserved in a
protected storage area in the Munch Museum, in Norway, under controlled
conditions of lighting, temperature (about 18°C) and relative humidity
(about 50%).

An international collaboration, led by the CNR (Italy), with the
University of Perugia (Italy), the University of Antwerp (Belgium), the
Bard Graduate Center in New York City (USA), the European Synchrotron
(ESRF, France), the German Electron Synchrotron (DESY, Hamburg) and the
Munch Museum, has studied in detail the nature of the various
cadmium-sulfide pigments used by Munch, and how these have degraded
over the years.

The findings provide relevant hints about the deterioration mechanism
of cadmium-sulfide-based paints, with significant implication for the
preventive conservation of The Scream.

"The synchrotron micro-analyses allowed us to pinpoint the main reason
that made the painting decline, which is moisture. We also found that
the impact of light in the paint is minor. I am very pleased that our
study could contribute to preserve this famous masterpiece," explains
Letizia Monico, one of the corresponding authors of the study.

Hitting the right formula for preservation

Monico and her colleagues studied selected cadmium-sulfide-based areas
of The Scream (1910?), as well as a corresponding micro-sample, using a
series of non-invasive in-situ spectroscopic analyses with portable
equipment of the European MOLAB platform in combination with the
techniques of micro X-ray diffraction, X-ray micro fluorescence and
micro X-ray absorption near edge structure spectroscopy mainly at the
ESRF, the European Synchrotron, in France, the world's most powerful
synchrotron. The study of the painting was integrated with
investigations of artificially aged mock-ups. The latter were prepared
using a historical cadmium yellow pigment powder and a cadmium yellow
oil paint tube that belonged to Munch. Both mock-ups had a similar
composition to the lake in the painting. "Our goal was to compare the
data from all these different pigments, in order to extrapolate the
causes that can lead to deterioration," says Monico.

The study shows that the original cadmium sulfide turns into cadmium
sulfate in the presence of chloride-compounds in high-moisture
conditions (relative humidity, or RH ?95%). This happens even if there
is no light.

"The right formula to preserve and display the main version of The
Scream on a permanent basis should include the mitigation of the
degradation of the cadmium yellow pigment by minimising the exposure of
the painting to excessively high moisture levels (trying to reach 45%
RH or lower), while keeping the lighting at standard values foreseen
for lightfast painting materials. The results of this study provide new
knowledge, which may lead to practical adjustments to the Museum's
conservation strategy," explains Irina C. A. Sandu, conservation
scientist at the Munch Museum.

"Today the Munch Museum stores and exhibits Edvard Munch's artworks at
a relative humidity of about 50% and at a temperature of around 20 °C.
These environmental conditions will also apply to the new Munch Museum
to be opened in Spring 2020. That said, the Museum will now look into
how this study may affect the current regime. Part of such a review
will be to consider how other materials in the collection will respond
to possible adjustments," adds Eva Storevik Tveit, paintings
conservator at the Munch Museum.

Cadmium-sulfide-based yellows are not only present in Munch's artwork
but also in the work of other artists contemporary to him, such as
Henri Matisse, Vincent van Gogh and James Ensor.

"The integration of non-invasive in-situ investigations at the
macro-scale level with synchrotron micro-analyses proved its worth in
helping us to understand complex alteration processes. It can be
profitably exploited for interrogating masterpieces that could suffer
from the same weakness," reports Costanza Miliani, coordinator of the
mobile platform MOLAB (operating in Europe under the IPERION CH
project) and second corresponding author of this study.

Monico and colleagues, especially Koen Janssens (University of
Antwerp), have a long-standing collaboration with the ESRF, the
European Synchrotron, and in particular with the scientist Marine
Cotte, to investigate these pigments and the best way to preserve the
original masterpieces.

"At the ESRF, ID21 is one of the very few beamlines in the world where
we can perform imaging X-ray absorption and fluorescence spectroscopy
analysis of the entire sample, at low energy and with sub-micrometer
spatial resolution," explains Janssens.

"EBS, the new Extremely Brilliant Source, the first-of-a-kind
high-energy synchrotron, which is under commissioning at the moment at
the ESRF, will further improve the capabilities of our instruments for
the benefit of world heritage science. We will be able to perform
microanalyses with increased sensitivity, and a greater level of
detail. Considering the complexity of these artistic materials, such
instrumental developments will highly benefit the analysis of our
cultural heritage," adds Cotte, ESRF scientist and CNRS researcher
director.

"This kind of work shows that art and science are intrinsically linked
and that science can help preserve pieces of art so that the world can
continue admiring them for years to come," concludes Miliani,
coordinator of MOLAB.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]European Synchrotron Radiation Facility.
Original written by Montserrat Capellas Espuny. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Letizia Monico, Laura Cartechini, Francesca Rosi, Annalisa Chieli,
Chiara Grazia, Steven De Meyer, Gert Nuyts, Frederik Vanmeert, Koen
Janssens, Marine Cotte, Wout De Nolf, Gerald Falkenberg, Irina
Crina Anca Sandu, Eva Storevik Tveit, Jennifer Mass, Renato Pereira
De Freitas, Aldo Romani, and Costanza Miliani. Probing the
chemistry of CdS paints in The Scream by in situ noninvasive
spectroscopies and synchrotron radiation x-ray techniques. Science
Advances, 2020 DOI: [19]10.1126/sciadv.aay3514
__________________________________________________________________

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Date:
May 15, 2020

Source:
University of Exeter

Summary:
Scientists have pioneered a new technique to expose hidden
biochemical pathways involving single molecules at the
nanoscale.

FULL STORY
__________________________________________________________________

Scientists have pioneered a new technique to expose hidden biochemical
pathways involving single molecules at the nanoscale.

A team of researchers from the University of Exeter's Living Systems
Institute used light to establish a means to monitor the structure and
properties of individual molecules in real time.

This innovative approach has allowed the team to temporarily bridge
molecules together to provide a crucial lens into their dynamics.

The study is published in the leading journal Nature Communications.

The structure of individual molecules and their properties, such as
chirality, are difficult to probe.

In the new study, led by Professor Frank Vollmer, the group was able to
observe reactions at the nanoscale which would otherwise be
inaccessible.

Thiol/disulfide exchange -- or the principal way disulfide bonds are
formed and rearranged in a protein -- has not yet been fully
scrutinised at equilibrium at the single-molecule level, in part
because this cannot be optically resolved in bulk samples.

However, light can circulate around micron-sized glass spheres to form
resonances. The trapped light can then repeatedly interact with its
surrounding environment. By attaching gold nanoparticles to the sphere,
light is enhanced and spatially confined down to the size of viruses
and amino acids.

The resulting optoplasmonic coupling allows for the detection of
biomolecules that approach the nanoparticles while they attach to the
gold, detach, and interact in a variety of ways.

Despite the sensitivity of this technique, there is lacking
specificity. Molecules as simple as atomic ions can be detected and
certain dynamics can be discerned, yet we cannot necessarily
discriminate them.

Serge Vincent remarks: "It took some time before we could narrow down
how to reliably sample individual molecules. Forward and backward
reaction rates at equilibrium are counterbalanced and, to certain
extent, we sought to lift the veil over these subtle dynamics."

Reaction pathways regulated by disulfide bonds can constrain
interactions to single thiol sensing sites on the nanoparticles. The
high fidelity of this approach establishes precise probing of the
characteristics of molecules undergoing the reaction.

By placing linkers on the gold surface, interactions with thiolated
species are isolated for based on their charge and the cycling itself.

Sensor signals have clear patterns related to whether reducing agent is
present. If it is, the signal oscillates in a controlled way, while if
it is not, the oscillations become stochastic.

For each reaction the monomer or dimer state of the leaving group can
be resolved.

Surprisingly, the optoplasmonic resonance shifts in frequency and/or
changes in linewidth when single molecules interact with it. In many
cases this result suggests a plasmon-vibrational coupling that could
help identify individual molecules, finally achieving characterisation.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Exeter. Note: Content may
be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Serge Vincent, Sivaraman Subramanian, Frank Vollmer. Optoplasmonic
characterisation of reversible disulfide interactions at single
thiol sites in the attomolar regime. Nature Communications, 2020;
11 (1) DOI: [19]10.1038/s41467-020-15822-8
__________________________________________________________________

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planet

Date:
May 18, 2020

Source:
Columbia University

Summary:
Humans have been wondering whether we alone in the universe
since antiquity. We know from the geological record that life
started relatively quickly, as soon our planet's environment was
stable enough to support it. We also know that the first
multicellular organism, which eventually produced today's
technological civilization, took far longer to evolve,
approximately 4 billion years.

FULL STORY
__________________________________________________________________

Humans have been wondering whether we alone in the universe since
antiquity.

We know from the geological record that life started relatively
quickly, as soon our planet's environment was stable enough to support
it. We also know that the first multicellular organism, which
eventually produced today's technological civilization, took far longer
to evolve, approximately 4 billion years.

But despite knowing when life first appeared on Earth, scientists still
do not understand how life occurred, which has important implications
for the likelihood of finding life elsewhere in the universe.

In a new paper published in the Proceeding of the National Academy of
Sciences today, David Kipping, an assistant professor in Columbia's
Department of Astronomy, shows how an analysis using a statistical
technique called Bayesian inference could shed light on how complex
extraterrestrial life might evolve in alien worlds.

"The rapid emergence of life and the late evolution of humanity, in the
context of the timeline of evolution, are certainly suggestive,"
Kipping said. "But in this study it's possible to actually quantify
what the facts tell us."

To conduct his analysis, Kipping used the chronology of the earliest
evidence for life and the evolution of humanity. He asked how often we
would expect life and intelligence to re-emerge if Earth's history were
to repeat, re-running the clock over and over again.

He framed the problem in terms of four possible answers: Life is common
and often develops intelligence, life is rare but often develops
intelligence, life is common and rarely develops intelligence and,
finally, life is rare and rarely develops intelligence.

This method of Bayesian statistical inference -- used to update the
probability for a hypothesis as evidence or information becomes
available -- states prior beliefs about the system being modeled, which
are then combined with data to cast probabilities of outcomes.

"The technique is akin to betting odds," Kipping said. "It encourages
the repeated testing of new evidence against your position, in essence
a positive feedback loop of refining your estimates of likelihood of an
event."

From these four hypotheses, Kipping used Bayesian mathematical formulas
to weigh the models against one another. "In Bayesian inference, prior
probability distributions always need to be selected," Kipping said.
"But a key result here is that when one compares the rare-life versus
common-life scenarios, the common-life scenario is always at least nine
times more likely than the rare one."

The analysis is based on evidence that life emerged within 300 million
years of the formation of the Earth's oceans as found in
carbon-13-depleted zircon deposits, a very fast start in the context of
Earth's lifetime. Kipping emphasizes that the ratio is at least 9:1 or
higher, depending on the true value of how often intelligence develops.

Kipping's conclusion is that if planets with similar conditions and
evolutionary time lines to Earth are common, then the analysis suggests
that life should have little problem spontaneously emerging on other
planets. And what are the odds that these extraterrestrial lives could
be complex, differentiated and intelligent? Here, Kipping's inquiry is
less assured, finding just 3:2 odds in favor of intelligent life.

This result stems from humanity's relatively late appearance in Earth's
habitable window, suggesting that its development was neither an easy
nor ensured process. "If we played Earth's history again, the emergence
of intelligence is actually somewhat unlikely," he said.

Kipping points out that the odds in the study aren't overwhelming,
being quite close to 50:50, and the findings should be treated as no
more than a gentle nudge toward a hypothesis.

"The analysis can't provide certainties or guarantees, only statistical
probabilities based on what happened here on Earth," Kipping said. "Yet
encouragingly, the case for a universe teeming with life emerges as the
favored bet. The search for intelligent life in worlds beyond Earth
should be by no means discouraged."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Columbia University. Original written by
Carla Cantor. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. David Kipping. An objective Bayesian analysis of life’s early start
and our late arrival. PNAS, 2020 DOI: [19]10.1073/pnas.1921655117
__________________________________________________________________

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Date:
May 18, 2020

Source:
Cornell University

Summary:
After examining a dozen types of suns and a roster of planet
surfaces, astronomers have developed a practical model - an
environmental color ''decoder'' - to tease out climate clues for
potentially habitable exoplanets in galaxies far away.

FULL STORY
__________________________________________________________________

After examining a dozen types of suns and a roster of planet surfaces,
Cornell University astronomers have developed a practical model -- an
environmental color "decoder" -- to tease out climate clues for
potentially habitable exoplanets in galaxies far away.

"We looked at how different planetary surfaces in the habitable zones
of distant solar systems could affect the climate on exoplanets," said
Jack Madden, who works in the lab of Lisa Kaltenegger, associate
professor of astronomy and director of Cornell's Carl Sagan Institute.

"Reflected light on the surface of planets plays a significant role not
only on the overall climate," Madden said, "but also on the detectable
spectra of Earth-like planets."

Madden and Kaltenegger are co-authors of "How Surfaces Shape the
Climate of Habitable Exoplanets," released May 18 in the Monthly
Notices of the Royal Astronomical Society.

In their research, they combine details of a planet's surface color and
the light from its host star to calculate a climate. For instance, a
rocky, black basalt planet absorbs light well and would be very hot,
but add sand or clouds and the planet cools; and a planet with
vegetation and circling a reddish K-star will likely have cool
temperatures because of how those surfaces reflect their suns' light.

"Think about wearing a dark shirt on a hot summer day. You're going to
heat up more, because the dark shirt is not reflecting light. It has a
low albedo (it absorbs light) and it retains heat," Madden said. "If
you wear a light color, such as white, its high albedo reflects the
light -- and your shirt keeps you cool.

It's the same with stars and planets, Kaltenegger said.

"Depending on the kind of star and the exoplanet's primary color -- or
the reflecting albedo -- the planet's color can mitigate some of the
energy given off by the star," Kaltenegger said. "What makes up the
surface of an exoplanet, how many clouds surround the planet, and the
color of the sun can change an exoplanet's climate significantly."

Madden said forthcoming instruments like the Earth-bound Extremely
Large Telescope will allow scientists to gather data in order to test a
catalog of climate predictions.

"There's an important interaction between the color of a surface and
the light hitting it," he said. "The effects we found based on a
planet's surface properties can help in the search for life."
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Cornell University. Original written by
Blaine Friedlander. Note: Content may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. Lisa Kaltenegger, Jack Madden. How surfaces shape the climate of
habitable exoplanets. Monthly Notices of the Royal Astronomical
Society, 2020; 495 (1): 1 DOI: [19]10.1093/mnras/staa387
__________________________________________________________________

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Date:
May 18, 2020

Source:
Heinrich-Heine University Duesseldorf

Summary:
Although most of the universe is made up of dark matter, very
little is known about it. Physicists have used a high-precision
experiment to look for interaction between dark matter and
normal matter.

FULL STORY
__________________________________________________________________

Although most of the universe is made up of dark matter, very little is
known about it. Physicists have used a high-precision experiment to
look for interaction between dark matter and normal matter.

The universe mainly consists of a novel substance and an energy form
that are not yet understood. This 'dark matter' and 'dark energy' are
not directly visible to the naked eye or through telescopes.
Astronomers can only provide proof of their existence indirectly, based
on the shape of galaxies and the dynamics of the universe. Dark matter
interacts with normal matter via the gravitational force, which also
determines the cosmic structures of normal, visible matter.

It is not yet known whether dark matter also interacts with itself or
with normal matter via the other three fundamental forces -- the
electromagnetic force, the weak and the strong nuclear force -- or some
additional force. Even very sophisticated experiments have so far not
been able to detect any such interaction. This means that if it does
exist at all, it must be very weak.

In order to shed more light on this topic, scientists around the globe
are carrying out various new experiments in which the action of the
non-gravitational fundamental forces takes place with as little outside
interference as possible and the action is then precisely measured. Any
deviations from the expected effects may indicate the influence of dark
matter or dark energy. Some of these experiments are being carried out
using huge research machines such as those housed at CERN, the European
Organization for Nuclear Research in Geneva. But laboratory-scale
experiments, for example in Düsseldorf, are also feasible, if designed
for maximum precision.

The team working under guidance of Prof. Stephan Schiller from the
Institute of Experimental Physics at HHU has presented the findings of
a precision experiment to measure the electrical force between the
proton ("p") and the deuteron ("d") in the journal Nature. The proton
is the nucleus of the hydrogen atom (H), the heavier deuteron is the
nucleus of deuterium (D) and consists of a proton and a neutron bound
together.

The Düsseldorf physicists study an unusual object, HD+, the ion of the
partially deuterated hydrogen molecule. One of the two electrons
normally contained in the electron shell is missing in this ion. Thus,
HD+ consists of a proton and deuteron bound together by just one
electron, which compensates for the repulsive electrical force between
them.

This results in a particular distance between the proton and the
deuteron, referred to as the 'bond length'. In order to determine this
distance, the HHU physicists have measured the rotation rate of the
molecule with eleven digits precision using a spectroscopy technique
they recently developed. The researchers used concepts that are also
relevant in the field of quantum technology, such as particle traps and
laser cooling.

It is extremely complicated to derive the bond length from the
spectroscopy results, and thus to deduct the strength of the force
exerted between the proton and the deuteron. This is because this force
has quantum properties. The theory of quantum electrodynamics (QED)
proposed in the 1940s must be used here. A member of the author team
spent two decades to advance the complex calculations and was recently
able to predict the bond length with sufficient precision.

This prediction corresponds to the measurement result. From the
agreement one can deduce the maximum strength of a modification of the
force between a proton and a deuteron caused by dark matter. Prof.
Schiller comments: "My team has now pushed down this upper limit more
than 20-fold. We have demonstrated that dark matter interacts much less
with normal matter than was previously considered possible. This
mysterious form of matter continues to remain undercover, at least in
the lab!"
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Heinrich-Heine University Duesseldorf.
Original written by Arne Claussen and editorial staff. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal Reference:
1. S. Alighanbari, G. S. Giri, F. L. Constantin, V. I. Korobov, S.
Schiller. Precise test of quantum electrodynamics and determination
of fundamental constants with HD ions. Nature, 2020; 581 (7807):
152 DOI: [19]10.1038/s41586-020-2261-5
__________________________________________________________________

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2D order protects several entangled states that could be used in quantum computing

Date:
May 18, 2020

Source:
Rice University

Summary:
Physicists have found surprising evidence of a link between the
2D quantum Hall effect and 3D topological materials that could
be used in quantum computing.

FULL STORY
__________________________________________________________________

U.S. and German physicists have found surprising evidence that one of
the most famous phenomena in modern physics -- the quantum Hall effect
-- is "reincarnated" in topological superconductors that could be used
to build fault-tolerant quantum computers.

The 1980 discovery of the quantum Hall effect kicked off the study of
topological orders, electronic states with "protected" patterns of
long-range quantum entanglement that are remarkably robust. The
stability of these protected states is extremely attractive for quantum
computing, which uses quantum entanglement to store and process
information.

In a study published online this month in Physical Review X (PRX),
theoretical physicists from Rice University, the University of
California, Berkeley (UC Berkeley), and the Karlsruhe Institute of
Technology (KIT) in Karlsruhe, Germany, presented strong numerical
evidence for a surprising link between 2D and 3D phases of topological
matter. The quantum Hall effect was discovered in 2D materials, and
laboratories worldwide are in a race to make 3D topological
superconductors for quantum computing.

"In this work we've shown that a particular class of 3D topological
superconductors should exhibit 'energy stacks' of 2D electronic states
at their surfaces," said Rice co-author Matthew Foster, an associate
professor of physics and astronomy and member of the Rice Center for
Quantum Materials (RCQM). "Each of these stacked states is a robust
'reincarnation' of a single, very special state that occurs in the 2D
quantum Hall effect."

The quantum Hall effect was first measured in two-dimensional
materials. Foster uses a "percolation" analogy to help visualize the
strange similarities between what occurs in 2D quantum Hall experiments
and the study's 3D computational models.

"Picture a sheet of paper with a map of rugged peaks and valleys, and
then imagine what happens as you fill that landscape with water," he
said. "The water is our electrons, and when the level of fluid is low,
you just have isolated lakes of electrons. The lakes are disconnected
from one another, and the electrons can't conduct across the bulk. If
water level is high, you have isolated islands, and in this case the
islands are like the electrons, and you also don't get bulk
conduction."

In Foster's analogy the rugged landscape is the electric potential of
the 2D material, and the level of ruggedness corresponds to amount of
impurities in the system. The water level represents the "Fermi
energy," a concept in physics that refers to the filling level of
electrons in a system. The edges of the paper map are analogous to the
1D edges that surround the 2D material.

"If you add water and tune the fluid level precisely to the point where
you have little bridges of water connecting the lakes and little
bridges of land connecting the islands, then it's as easy to travel by
water or land," Foster said. "That is the percolation threshold, which
corresponds to the transition between topological states in quantum
Hall. This is the special 2D state in quantum Hall.

"If you increase the fluid level more, now the electrons are trapped in
isolated islands, and you'd think, 'Well, I have the same situation I
had before, with no conduction.' But, at the special transition, one of
the electronic states has peeled away to the edge. Adding more fluid
doesn't remove the edge state, which can go around the whole sample,
and nothing can stop it."

The analogy describes the relationship between robust edge conduction
and bulk fine-tuning through the special transition in the quantum Hall
effect. In the PRX study, Foster and co-authors Bjo?rn Sbierski of UC
Berkeley and Jonas Karcher of KIT studied 3D topological systems that
are similar to the 2D landscapes in the analogy.

"The interesting stuff in these 3D systems is also only happening at
the boundary," Foster said. "But now our boundaries aren't 1D edge
states, they are 2D surfaces."

Using "brute-force numerical calculations of the surface states,"
Sbierski, Karcher and Foster found a link between the critical 2D
quantum Hall state and the 3D systems. Like the 1D edge state that
persists above the transition energy in 2D quantum Hall materials, the
calculations revealed a persistent 2D boundary state in the 3D systems.
And not just any 2D state; it is exactly the same 2D percolation state
that gives rise to 1D quantum Hall edge states.

"What was a fine-tuned topological quantum phase transition in 2D has
been 'reincarnated' as the generic surface state for a higher
dimensional bulk," Foster said. "In 2018 study, my group identified an
analogous connection between a different, more exotic type of 2D
quantum Hall effect and the surface states of another class of 3D
topological superconductors. With this new evidence, we are now
confident there is a deep topological reason for these connections, but
at the moment the mathematics remain obscure."

Topological superconductors have yet to be realized experimentally, but
physicists are trying to create them by adding impurities to
topological insulators. This process, known as doping, has been widely
used to make other types of unconventional superconductors from bulk
insulators.

"We now have evidence that three of the five 3D topological phases are
tied to 2D phases that are versions of the quantum Hall effect, and all
three 3D phases could be realized in 'topological superconductors,'"
Foster said.

Foster said conventional wisdom in condensed matter physics has been
that topological superconductors would each host only one protected 2D
surface state and all other states would be adversely affected by
unavoidable imperfections in the solid-state materials used to make the
superconductors.

But Sbierski, Karcher and Foster's calculations suggest that isn't the
case.

"In quantum Hall, you can tune anywhere and still get this robust
plateau in conductance, due to the 1D edge states," Foster said. "Our
work suggests that is also the case in 3D. We see stacks of critical
states at different energy levels, and all of them are protected by
this strange reincarnation of the 2D quantum Hall transition state."

The authors also set the stage for experimental work to verify their
findings, working out details of how the surface states of the 3D
phases should appear in various experimental probes.

"We provide precise statistical 'fingerprints' for the surface states
of the topological phases," Foster said. "The actual wave functions are
random, due to disorder, but their distributions are universal and
match the quantum Hall transition."

The research was supported by a National Science Foundation CAREER
grant (1552327), the German National Academy of Sciences Leopoldina
(LPDS 2018-12), a KIT research travel grant, German state graduate
funding and the UC Berkeley Library's Berkeley Research Impact
Initiative.
make a difference: sponsored opportunity
__________________________________________________________________

Story Source:

[17]Materials provided by [18]Rice University. Note: Content may be
edited for style and length.
__________________________________________________________________

Journal Reference:
1. Björn Sbierski, Jonas F. Karcher, Matthew S. Foster. Spectrum-Wide
Quantum Criticality at the Surface of Class AIII Topological
Phases: An “Energy Stack” of Integer Quantum Hall Plateau
Transitions. Physical Review X, 2020; 10 (2) DOI:
[19]10.1103/PhysRevX.10.021025
__________________________________________________________________

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Novel training method could shrink carbon footprint for greener deep learning

Date:
May 18, 2020

Source:
Rice University

Summary:
Engineers have found a way to train deep neural networks for a
fraction of the energy required today. Their Early Bird method
finds key network connectivity patterns early in training,
reducing the computations and carbon footprint for training deep
learning.

FULL STORY
__________________________________________________________________

Rice University's Early Bird could care less about the worm; it's
looking for megatons of greenhouse gas emissions.

Early Bird is an energy-efficient method for training deep neural
networks (DNNs), the form of artificial intelligence (AI) behind
self-driving cars, intelligent assistants, facial recognition and
dozens more high-tech applications.

Researchers from Rice and Texas A&M University unveiled Early Bird
April 29 in a spotlight paper at ICLR 2020, the International
Conference on Learning Representations. A study by lead authors Haoran
You and Chaojian Li of Rice's Efficient and Intelligent Computing (EIC)
Lab showed Early Bird could use 10.7 times less energy to train a DNN
to the same level of accuracy or better than typical training. EIC Lab
director Yingyan Lin led the research along with Rice's Richard
Baraniuk and Texas A&M's Zhangyang Wang.

"A major driving force in recent AI breakthroughs is the introduction
of bigger, more expensive DNNs," Lin said. "But training these DNNs
demands considerable energy. For more innovations to be unveiled, it is
imperative to find 'greener' training methods that both address
environmental concerns and reduce financial barriers of AI research."

Training cutting-edge DNNs is costly and getting costlier. A 2019 study
by the Allen Institute for AI in Seattle found the number of
computations needed to train a top-flight deep neural network increased
300,000 times between 2012-2018, and a different 2019 study by
researchers at the University of Massachusetts Amherst found the carbon
footprint for training a single, elite DNN was roughly equivalent to
the lifetime carbon dioxide emissions of five U.S. automobiles.

DNNs contain millions or even billions of artificial neurons that learn
to perform specialized tasks. Without any explicit programming, deep
networks of artificial neurons can learn to make humanlike decisions --
and even outperform human experts -- by "studying" a large number of
previous examples. For instance, if a DNN studies photographs of cats
and dogs, it learns to recognize cats and dogs. AlphaGo, a deep network
trained to play the board game Go, beat a professional human player in
2015 after studying tens of thousands of previously played games.

"The state-of-art way to perform DNN training is called progressive
prune and train," said Lin, an assistant professor of electrical and
computer engineering in Rice's Brown School of Engineering. "First, you
train a dense, giant network, then remove parts that don't look
important -- like pruning a tree. Then you retrain the pruned network
to restore performance because performance degrades after pruning. And
in practice you need to prune and retrain many times to get good
performance."

Pruning is possible because only a fraction of the artificial neurons
in the network can potentially do the job for a specialized task.
Training strengthens connections between necessary neurons and reveals
which ones can be pruned away. Pruning reduces model size and
computational cost, making it more affordable to deploy fully trained
DNNs, especially on small devices with limited memory and processing
capability.

"The first step, training the dense, giant network, is the most
expensive," Lin said. "Our idea in this work is to identify the final,
fully functional pruned network, which we call the 'early-bird ticket,'
in the beginning stage of this costly first step."

By looking for key network connectivity patterns early in training, Lin
and colleagues were able to both discover the existence of early-bird
tickets and use them to streamline DNN training. In experiments on
various benchmarking data sets and DNN models, Lin and colleagues found
Early Bird could emerge as little as one-tenth or less of the way
through the initial phase of training.

"Our method can automatically identify early-bird tickets within the
first 10% or less of the training of the dense, giant networks," Lin
said. "This means you can train a DNN to achieve the same or even
better accuracy for a given task in about 10% or less of the time
needed for traditional training, which can lead to more than one order
savings in both computation and energy."

Developing techniques to make AI greener is the main focus of Lin's
group. Environmental concerns are the primary motivation, but Lin said
there are multiple benefits.

"Our goal is to make AI both more environmentally friendly and more
inclusive," she said. "The sheer size of complex AI problems has kept
out smaller players. Green AI can open the door enabling researchers
with a laptop or limited computational resources to explore AI
innovations."

Additional co-authors include Pengfei Xu, Yonggan Fu and Yue Wang, all
of Rice, and Xiaohan Chen of Texas A&M.

The research was supported by the National Science Foundation (1937592,
1937588).
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Rice University. Note: Content may be
edited for style and length.
__________________________________________________________________

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Date:
May 18, 2020

Source:
University of Pennsylvania

Summary:
To break through a looming bandwidth bottleneck, engineers are
exploring some of light's harder-to-control properties. Now, two
new studies have shown a system that can manipulate and detect
one such property: orbital angular momentum. Critically, they
are the first to do so on small semiconductor chips and with
enough precision that it can be used as a medium for
transmitting information.

FULL STORY
__________________________________________________________________

As computers get more powerful and connected, the amount of data that
we send and receive is in a constant race with the technologies that we
use to transmit it. Electrons are now proving insufficiently fast and
are being replaced by photons as the demand for fiber optic internet
cabling and data centers grow.

Though light is much faster than electricity, in modern optical
systems, more information is transmitted by layering data into multiple
aspects of a light wave, such as its amplitude, wavelength and
polarization. Increasingly sophisticated "multiplexing" techniques like
these are the only way to stay ahead of the increasing demand for data,
but those too are approaching a bottleneck. We are simply running out
of room to store more data in the conventional properties of light.

To break through this barrier, engineers are exploring some of light's
harder-to-control properties. Now, two studies from the University of
Pennsylvania's School of Engineering and Applied Science have shown a
system that can manipulate and detect one such property known as the
orbital angular momentum, or OAM, of light. Critically, they are the
first to do so on small semiconductor chips and with enough precision
that it can be used as a medium for transmitting information.

The matched pair of studies, published in the journal Science, was done
in collaboration with researchers at Duke University, Northeastern
University, the Polytechnic University of Milan, Hunan University and
the U.S. National Institute of Standards and Technology.

One study, led by Liang Feng, assistant professor in the departments of
Materials Science and Engineering and Electrical and Systems
Engineering, demonstrates a microlaser which can be dynamically tuned
to multiple distinct OAM modes. The other, led by Ritesh Agarwal,
professor in the Department of Materials Science and Engineering, shows
how a laser's OAM mode can be measured by a chip-based detector. Both
studies involve collaborations between the Agarwal and Feng groups at
Penn.

Such "vortex" lasers, named for the way their light spirals around
their axis of travel, were first demonstrated by Feng with quantum
symmetry-driven designs in 2016. However, Feng and other researchers in
the field have thus far been limited to transmitting a single, pre-set
OAM mode, making them impractical for encoding more information. On the
receiving end, existing detectors have relied on complex filtering
techniques using bulky components that have prevented them from being
integrated directly onto a chip, and are thus incompatible with most
practical optical communications approaches.

Together, this new tunable vortex micro-transceiver and receiver
represents the two most critical components of a system that can enable
a way of multiplying the information density of optical communication,
potentially shattering that looming bandwidth bottleneck.

The ability to dynamically tune OAM values would also enable a photonic
update to a classic encryption technique: frequency hopping. By rapidly
switching between OAM modes in a pre-defined sequence known only to the
sender and receiver, optical communications could be made impossible to
intercept.

"Our findings mark a large step towards launching large-capacity
optical communication networks and confronting the upcoming information
crunch," says Feng.

In the most basic form of optical communication, transmitting a binary
message is as simple as representing 1s and 0s by whether the light is
on or off. This is effectively a measure of the light's amplitude --
how high the peak of the wave is -- which we experience as brightness.
As lasers and detectors become more precise, they can consistently emit
and distinguish between different levels of amplitude, allowing for
more bits of information to be contained in the same signal.

Even more sophisticated lasers and detectors can alter other properties
of light, such as its wavelength, which corresponds to color, and its
polarization, which is the orientation of the wave's oscillations
relative to its direction of travel. Many of these properties can be
set independently of each other, allowing for increasingly dense
multiplexing.

Orbital angular momentum is yet another property of light, though it is
considerably harder to manipulate, given the complexity of the
nanoscale features necessary to generate it from computer-chip-sized
lasers. Circularly polarized light carries an electric field that
rotates around its axis of travel, meaning its photons have a quality
known as spin angular momentum, or SAM. Under highly controlled
spin-orbit interactions, SAM can be locked or converted into another
property, orbital angular momentum, or OAM.

The research on a dynamically tunable OAM laser based on this concept
was led by Feng and graduate student Zhifeng Zhang.

In this new study, Feng, Zhang and their colleagues began with a
"microring" laser, which consists of a ring of semiconductor, only a
few microns wide, through which light can circulate indefinitely as
long as power is supplied. When additional light is "pumped" into the
ring from control arms on either side of the ring, the delicately
designed ring emits circularly polarized laser light. Critically,
asymmetry between the two control arms allows for the SAM of the
resulting laser to be coupled with OAM in a particular direction.

This means that rather than merely rotating around the axis of the
beam, as circularly polarized light does, the wavefront of such a laser
orbits that axis and thus travels in a helical pattern. A laser's OAM
"mode" corresponds to its chirality, the direction those helices twist,
and how close together its twists are.

"We demonstrated a microring laser that is capable of emitting five
distinct OAM modes," Feng says. "That may increase the data channel of
such lasers by up to five times."

Being able to multiplex the OAM, SAM and wavelength of laser light is
itself unprecedented, but not particularly useful without a detector
that can differentiate between those states and read them out.

In concert with Feng's work on the tunable vortex microlaser, the
research on the OAM detector was led by Agarwal and Zhurun Ji, a
graduate student in his lab.

"OAM modes are currently detected through bulk approaches such as mode
sorters, or by filtering techniques such as modal decomposition,"
Agarwal says, "but none of these methods are likely to work on a chip,
or interface seamlessly with electronic signals."

Agarwal and Ji built upon their previous work with Weyl semimetals, a
class of quantum materials that have bulk quantum states whose
electrical properties can be controlled using light. Their experiments
showed that they could control the direction of electrons in those
materials by shining light with different SAM onto it.

Along with their collaborators, Agarwal and Ji drew on this phenomenon
by designing a photodetector that is similarly responsive to different
OAM modes. In their new detector, the photocurrent generated by light
with different OAM modes produced unique current patterns, which
allowed the researchers determine the OAM of light impinging on their
device.

"These results not only demonstrate a novel quantum phenomenon in the
light-matter interaction," Agarwal says, "but for the first time enable
the direct read-out of the phase information of light using an on-chip
photodetector. These studies hold great promise for designing highly
compact systems for future optical communication systems."

Next, Agarwal and Feng plan to collaborate on such systems. By
combining their unique expertise to fabricate on-chip vortex
microlasers and detectors that can uniquely detect light's OAM, they
will design integrated systems to demonstrate new concepts in optical
communications with enhanced data transmission capabilities for
classical light and upon increasing the sensitivity to single photons,
for quantum applications. This demonstration of a new dimension for
storing information based on OAM modes can help create richer
superposition quantum states to increase information capacity by a few
orders of magnitude.

These two strongly-tied studies were partially supported by the
National Science Foundation, the U.S. Army Research Office and the
Office of Naval Research. Research on the vortex microlaser was done in
collaboration with Josep M. Jornet, associate professor at Northeastern
University and Stefano Longhi, professor at the Polytechnic University
of Milan in Italy and Natalia M. Litchinitser, professor at Duke
University. Penn's Xingdu Qiao, Bikashkali Midya, Kevin Liu, Tianwei
Wu, Wenjing Liu and Duke's Jingbo Sun also contributed to the work.
Research on the photodetector was done in collaboration with Albert
Davydov from the National Institute of Standards and Technology (NIST)
and Anlian Pan from Hunan University. Penn's Wenjing Liu, Xiaopeng Fan,
Zhifeng Zhang and NIST's Sergiy Krylyuk also contributed to the work.
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]University of Pennsylvania. Note: Content
may be edited for style and length.
__________________________________________________________________

Journal References:
1. Zhifeng Zhang, Xingdu Qiao, Bikashkali Midya, Kevin Liu, Jingbo
Sun, Tianwei Wu, Wenjing Liu, Ritesh Agarwal, Josep Miquel Jornet,
Stefano Longhi, Natalia M. Litchinitser, Liang Feng. Tunable
topological charge vortex microlaser. Science, 2020; 368 (6492):
760 DOI: [19]10.1126/science.aba8996
2. Zhurun Ji, Wenjing Liu, Sergiy Krylyuk, Xiaopeng Fan, Zhifeng
Zhang, Anlian Pan, Liang Feng, Albert Davydov, Ritesh Agarwal.
Photocurrent detection of the orbital angular momentum of light.
Science, 2020; 368 (6492): 763 DOI: [20]10.1126/science.aba9192
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Researchers find aluminum in water could affect lead's solubility -- in
certain cases

Date:
May 18, 2020

Source:
Washington University in St. Louis

Summary:
Until recently, researchers have not inspected the interplay
between three common chemicals found in drinking water. Research
has now found they all affect each other and a closer look is
needed.

FULL STORY
__________________________________________________________________

It is not uncommon to find aluminum in municipal water systems. It's
part of a treatment chemical used in some water treatment processes.
Recently, however, it has been discovered in lead scale, deposits that
form on lead water pipes.

The aluminum presence in pipes is both unsurprising and, in the
quantities researchers saw in water pipes, not a health concern,
according to Daniel Giammar, the Walter E. Browne Professor of
Environmental Engineering in the McKelvey School of Engineering at
Washington University in St. Louis. But no one had looked at how it
might affect the larger municipal system.

In particular, Giammar wanted to find out, "What is that aluminum doing
to the behavior of the lead in the scale?" As long as the lead is bound
to the scale, it doesn't enter the water system.

Giammar and a team ran several experiments and found that, in a lab
setting, aluminum does have a small but important effect on lead's
solubility under certain conditions. Their results were published in
late April in Environmental Science & Technology.

The experiments were carried out in large part by visiting PhD student
Guiwei Li, who was able to complete the work during his brief stay at
Washington University before returning to the Chinese Academy of
Sciences.

In simplified models, the researchers took a look at how phosphate,
aluminum and a combination of the two, affected a strip of lead in a
jar of water with a composition close to that of water found in many
water systems. The aim: to better understand lead's solubility, or the
amount that would dissolve and make its way into the water when
impacted by those chemicals.

In the jar in which only aluminum was added, there was no effect on the
solubility of the lead strip; lead had dissolved into the water at a
concentration of about 100 micrograms per liter.

In the jar in which only phosphate was added, the concentration of lead
in the water decreased from about 100 micrograms per liter to less than
one.

In the jar in which both aluminum and phosphate were added, the
concentration of lead in the water decreased from about 100 micrograms
per liter to about 10 micrograms per liter.

Ten micrograms of lead per liter of water is still below drinking water
standards, Giammar said, but it's still more lead in the water than was
seen in the jar without aluminum. "This tells us what our next
experiment should be," he said. His lab will do these experiments with
real lead pipes, as they have done in the past.

"This showed us things that were surprising," he said. "Some people
would have thought that aluminum wasn't doing anything because it's
inert. But then in our work, we saw that it actually affects lead
solubility."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]Washington University in St. Louis.
Original written by Brandie Jefferson. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. Guiwei Li, Yeunook Bae, Anushka Mishrra, Baoyou Shi, Daniel E.
Giammar. Effect of Aluminum on Lead Release to Drinking Water from
Scales of Corrosion Products. Environmental Science & Technology,
2020; DOI: [19]10.1021/acs.est.0c00738
__________________________________________________________________

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to insulator

Date:
May 18, 2020

Source:
RIKEN

Summary:
Tantalum disulfide is a mysterious material. According to
textbook theory, it should be a conducting metal, but in the
real world it acts like an insulator. Using a scanning tunneling
microscope, researchers have taken a high-resolution look at the
structure of the material, revealing why it demonstrates this
unintuitive behavior.

FULL STORY
__________________________________________________________________

Tantalum disulfide is a mysterious material. According to textbook
theory, it should be a conducting metal, but in the real world it acts
like an insulator. Using a scanning tunneling microscope, researchers
from the RIKEN Center for Emergent Matter Science have taken a
high-resolution look at the structure of the material, revealing why it
demonstrates this unintuitive behavior. It has long been known that
crystalline materials should be good conductors when they have an odd
number of electrons in each repeating cell of the structure, but may be
poor conductors when the number is even. However, sometimes this
formula does not work, with one case being "Mottness," a property based
on the work of Sir Nevill Mott. According to that theory, when there is
strong repulsion between electrons in the structure, it leads the
electrons to become "localized" -- paralyzed in other words -- and
being unable to move around freely to create an electric current. What
makes the situation complicated is that there are also situations where
electrons in different layers of a 3-D structure can interact, pairing
up to create a bilayer structure with an even number of electrons. It
has been previously suggested that this "pairing" of electrons would
restore the textbook understanding of the insulator, making it
unnecessary to invoke "Mottness" as an explanation.

For the current study, published in Nature Communications, the research
group decided to look at tantalum disulfide, a material with 13
electrons in each repeating structure, which should therefore be a
conductor. However, it is not, and there has been controversy over
whether this property is caused by its "Mottness" or by a pairing
structure.

To perform the research, the researchers created crystals of tantalum
disulfide and then cleaved the crystals in a vacuum to reveal
ultra-clean surfaces which they then examined, at a temperature close
to absolute zero -- with a method known as scanning tunneling
microscopy -- a method involving a tiny and extremely sensitive metal
tip that can sense where electrons are in a material, and their degree
of conducting behavior, by using the quantum tunneling effect. Their
results showed that there was indeed a stacking of layers which
effectively arranged them into pairs. Sometimes the crystals cleaved
between the pairs of layers, and sometimes through a pair, breaking it.
They performed spectroscopy on both the paired and unpaired layers and
found that even the unpaired ones are insulating, leaving Mottness as
the only explanation.

According to Christopher Butler, the first author of the study, "The
exact nature of the insulating state and of the phase transitions in
tantalum disulfide have been long-standing mysteries, and it was very
exciting to find that Mottness is a key player, aside from the pairing
of the layers. This is because theorists suspect that a Mott state
could set the stage for an interesting phase of matter known as a
quantum spin liquid."

Tetsuo Hanaguri, who led the research team, said, "The question of what
makes this material move between insulating to conducting phases has
long been a puzzle for physicists, and I am very satisfied we have been
able to put a new piece into the puzzle. Future work may help us to
find new interesting and useful phenomena emerging from Mottness, such
as high-temperature superconductivity."
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__________________________________________________________________

Story Source:

[17]Materials provided by [18]RIKEN. Note: Content may be edited for
style and length.
__________________________________________________________________

Journal Reference:
1. C. J. Butler, M. Yoshida, T. Hanaguri, Y. Iwasa. Mottness versus
unit-cell doubling as the driver of the insulating state in
1T-TaS2. Nature Communications, 2020; 11 (1) DOI:
[19]10.1038/s41467-020-16132-9
__________________________________________________________________

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