Tech

That visible light holds the character of a wave can be demonstrated in simple optics experiments, or directly witnessed when rainbows appear in the sky. Although the subtle laws of quantum mechanics, that is, wave mechanics, ultimately govern all the processes of electron transportelectrons in solids, their wave-like nature of the electrons is not often apparent to the casual observer. A classical picture of electrons as solid particles goes surprisingly far in explaining electric currents in metals. As high school students see in experiments with water waves, and we observe and use with light waves in many optical devices, interference is a fundamental property associated with wave-like behavior. Indeed, Davisson and Germer's famous observation of interference in experiments with dilute beams of electrons, nearly a century ago, gave key experimental support to the correctness of the then-new quantum theory.

In experiments on solids, however, signatures of quantum interference are rare and hard to observe. This is essentially because there are so many electrons, and so many ways in which they can be 'scrambled up', that most interference effects are invisible to experiments that probe distances of more than a few atomic spacings.

One of the themes of research in the Physics of Quantum Materials department is the study of exotic strange layered metals from a structural class with the equally strange name 'delafossites', stemming from the famous French crystallographer Gabriel Delafosse. They are notable because they conduct electricity incredibly well. Indeed, at room temperature one of them, PtCoO2, is the best electrical conductor ever discovered. As part of our research on the delafossites, we were studying how the conduction perpendicular to the layers depends on magnetic field, in crystals that had been sculpted into particular geometries using a focused ion beam (see Fig. 1). To our complete surprise, we observed strong oscillations in this conductivity, of a kind that are a signature of some kindsignaling of interference (see Fig. 2). After a long period of follow-up experiments at this institute and in the new group of our former colleagues Philip Moll and Carsten Putzke, now at EPFL in Lausanne, we collaborated with theorists Takashi Oka and Roderich Moessner in our neighbour institute in Dresden and Ady Stern from the Weizmann Institute in Israel to propose an explanation for what is going on. Remarkably, it requires a form of quantum coherence over macroscopic distances of up to 50000 atomic lattice spacings. It is only observable because of the remarkable purity of the delafossites, whose origin we established in another set of experiments, also published recently. High quality materials continue to hold a wealth of surprises and delights for those who make and study them!

Measuring air quality across London could help fight COVID-19 by providing a rapid means of deciding whether to reduce public transport movement - given strong links between exposure to air pollution and COVID-19 transmission, a new study reveals.

Analysis of air pollution, COVID-19 cases and fatality rates in London demonstrates a connection between increased levels of nitrogen dioxide (NO2) and particulate matter (PM2.5) and higher risk of viral transmission.

Scientists at the Universities of Birmingham and Cambridge say that this shows air pollution could be used as an indicator to rapidly identify vulnerable parts of a city such as London - informing decisions to suspend or reduce operation of buses, trains and Underground.

Researchers have published their findings today in Science of The Total Environment, highlighting that using public transport in the UK during a pandemic outbreak has a six-fold increased risk of contracting an acute respiratory infection.

City boroughs with access to London Underground interchange stations also have higher pandemic case rates as users are exposed to a higher number of individuals compared to through stations.

Report author Dr Ajit Singh, from the University of Birmingham, commented: "Short-term exposure to NO2 and PM2.5is significantly linked to an increased risk of contracting and dying from COVID-19. Exposure to such air pollutants can compromise lung function and increase risk of death from the virus.

"Levels of airborne PM2.5in the London Underground during summer are often several times higher than other transport environments such as cycling, buses or cars. We recommend a strategy that tailors the level of public transport activity in cities like London according to COVID-19 vulnerability based on air pollution levels across the city.

"This could help decision-makers take the right measures to counter COVID-19 in London - for example deploying transport staff and arranging dedicated services for key workers."

Scientists have earlier found the greatest PM2.5concentrations across the London Underground network on the Victoria Line (16 times higher than the roadside environment), followed by the Northern, Bakerloo and Piccadilly lines.

Routine cleaning and maintenance of the London Underground ranges from litter removal to preventing safety incidents rather than reducing PM concentrations.

Co-author Dr Manu Sasidharan, of the University of Cambridge, commented: "Human-mobility reduction measures provide the greatest benefit in the fight against COVID-19. We need to balance the public health benefits of closing public transport during a pandemic against the socio-economic impacts of reducing mobility.

"Determining the vulnerability of city regions to coronavirus might help to achieve such trade-offs - air pollution levels can serve as one of the indicators to assess this vulnerability."

The number of positive COVID-19 cases considered in the study were only those reported at hospitals - it does not include people self-isolating due to COVID-19.

NASA-NOAA's Suomi NPP satellite provided forecasters with visible image of the Eastern Pacific Ocean's second tropical storm of the season, Boris. Boris formed just east of the Central Pacific Ocean's boundary as it was moving into that region.

The Central Pacific Ocean Basin is the central area of the North Pacific Ocean. Its boundaries are the Marshall Islands to the west and the Line Islands to the east. Hawaii lies in the Central Pacific Ocean.

Satellites have been monitoring the progress and development of Tropical Depression 3 in the Eastern Pacific for two days. On June 25, the depression organized and strengthened into a tropical storm and was renamed Boris at 5 p.m. EDT. Boris reached maximum strength with maximum sustained winds near 40 mph and weakened back to a depression in 12 hours by 5 a.m. EDT (0900 UTC) on June 26.

Visible imagery from NASA satellites help forecasters understand if a storm is organizing or weakening. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of Boris during its short time as a tropical storm on June 26, 2020.

At 11 a.m. EDT (1500 UTC) on June 26, NOAA's Central Pacific Hurricane Center noted the center of Tropical Depression Boris was located near latitude 12.0 degrees north and longitude 139.0 degrees west. That is about 1,195 miles (1,920 km) east-southeast of Hilo, Hawaii. The depression was moving toward the west-northwest near 7 mph (11 kph), and this motion should continue through tonight. Maximum sustained winds were near 35 mph (55 kph) with higher gusts.

A turn toward the west is expected late on Friday June 26, or on Saturday June 27. Gradual weakening is forecast during the next couple of days, and Boris is forecast to degenerate to a remnant low pressure area Saturday night or Sunday.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

Erlantz Lizundia-Fernandez, who lectures in the UPV/EHU's Department of Graphic Design and Engineering Projects, works with renewable polymers. "We are seeking to drive forward the circular economy so we use renewable materials to substitute the applications that currently come from petroleum, or, for example, so they can be used to substitute scarce elements such as lithium or cobalt. My research focusses on cellulose, and out of all the types of cellulose, I have worked mainly with nanocrystals," he said.

As an expert in the subject, Lizundia has reviewed together with another three researchers from Italy and Canada the main developments and advances that have emerged recently in the area of cellulose nanocrystals. "There is a huge number of research papers explaining the synthesis of materials of this type and which are geared towards what is known as proof of concept, in other words, to show that they can be used for a specific application. Cellulose nanocrystals have been widely used to mechanically strengthen polymers. Yet there are hardly any pieces of work that catalogue and explain the applications of hybrid materials produced using cellulose nanocrystals. This is what we have contributed: we have described the state of the art in this area of knowledge by conducting an in-depth review of the papers published in this respect," explained the researcher.

Cellulose crystals can be extracted from any object that contains cellulose, be it a tree or a newspaper, and these crystals are used as the base, like a matrix, to produce multifunctional materials by hybridizing them with other components, such as metal oxide nanoparticles, carbon nanoparticles or others of natural origin. The materials created have numerous interesting properties: they are renewable and biodegradable, they can be obtained simply and cost-effectively, they offer great flexibility, are of low density and high porosity, and have excellent mechanical, thermal and physico-chemical properties, among other things. In the analysis they explored three aspects of hybrid materials in depth: the manufacturing process by which they are formed, the types of hybrid materials produced, and the applications for which they are used.

A whole host of applications in engineering and medicine

Lizundia and the other researchers reviewed the manufacturing methods used to form hybrid materials with a range of morphologies and shapes. "The most widely used method is the simplest of all," they said in the article: cellulose nanocrystals and the other elements destined to form the hybrid material are blended in a solution; this solution is decanted onto a surface and the water is allowed to evaporate." Through this technique the cellulose nanocrystals produce helix-shaped structures, chiral nematic structures. "The special feature of these structures is that they provide the material with structural colour. The nanocrystals are organised into layers and, depending on the distance between the layers, the hybrid material will reflect light in one wavelength or another, which is the same as saying that it will be in one colour or another," added Lizundia.

Apart from the above-mentioned manufacturing method, the study also took filtering, 3D printing, layer-by-layer assembly and the sol-gel process into account. In all the cases the degree of development of the method is described and the features of the materials produced by it are quoted. However, an entire chapter is devoted afterwards to the features of the nanohybrids formed in the various studies analysed; this is followed by a classification in terms of the elements added to the nanocrystals: metals, metal oxides, carbon nanofibres and nanoparticles, graphene layers, luminescent nanoparticles, etc. Finally, the applications proposed for hybrid materials are examined, focussing mainly on the fields of engineering and medicine. Sensors, catalytic converters, wastewater treatment materials and energy applications developed by means of cellulose nanocrystals stand out among engineering applications. And among those geared towards medical applications they quote contributions made by materials to areas, such as tissue engineering, drug delivery, antibacterial solutions or wound dressings.

In each of the parts mentioned they review what has been achieved in the different pieces of research, but as experts in the subject they also provide their own assessment about the potential of the materials and what remains to be developed. Lizundia reached the following conclusion: "This work has served to bring together all the research spread across different locations, and we are offering a complete picture of the level of development of hybrid materials. That way we hope that interest in them will increase and that research in this area will be encouraged to fill the gaps we have found, such as a nanotoxicity study in medical applications or the establishing of the environmental impact of these materials."

Apolipoprotein E (ApoE) is kind of like a delivery service for the human brain. It supplies neurons with important nutrients, including with polyunsaturated fatty acids - which are building blocks of the membranes surrounding the neurons. In addition, certain unsaturated fatty acids are converted into so-called endocannabinoids. These are endogenous signaling molecules that regulate numerous functions of the nervous system, such as memory but also the control of immune response, thereby protecting the brain from inflammation.

The ApoE cargo reaches the neurons via a membrane receptor called sortilin. In a process known as endocytosis, sortilin binds ApoE and transports it into the interior of the neuron through invaginations of the cell membrane. The interaction of ApoE and sortilin has a major impact on our brain health: If not enough polyunsaturated fatty acids reach our gray cells, they begin to waste away and become susceptible to inflammatory responses.

But not all ApoE is the same. There are three gene variants in humans: ApoE2, ApoE3 and ApoE4. They do not differ in their function of transporting lipids. The ability to bind to sortilin is also the same in all variants. However, people who carry the E4 variant have a twelve times greater risk of developing Alzheimer's than those with the E3 form. About 15 percent of people carry ApoE4. "Why ApoE4 significantly increases the risk of Alzheimer's is one of the central questions in Alzheimer's research," says Professor Thomas Willnow, who for many years has been studying the development of neurodegenerative diseases at the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC). Willnow is also affiliated with Charité - Universitätsmedizin Berlin and Aarhus University.

ApoE4 prevents the recycling of sortilin

A study by Willnow's lab has now provided a possible explanation for why ApoE4 poses such a danger to the brain. The lead author of the study, which was recently published in the journal Alzheimer's & Dementia, is Dr. Antonino Asaro from the MDC. The study found that in the E3 variant, endocytosis functions smoothly: Sortilin binds the lipid-loaded ApoE3. After depositing its cargo inside the neurons, sortilin returns to the cell surface to bind new ApoE. This process repeats itself many times per hour, thus supplying neurons with sufficient amounts of essential fatty acids.

It comes to a standstill, however, when ApoE4 is involved. If sortilin binds ApoE4 and transports it into the neuron's interior, the receptor clumps up inside the cell. It is unable to return to the cell surface, and the endocytosis process grinds to a halt. Eventually, fewer and fewer fatty acids are taken up, the gray cells cannot protect themselves and become inflamed. As a result, they are susceptible to cell death as the aging process sets in - and eventually die. The risk of developing Alzheimer's dementia thus increases dramatically.

"We used a custom mouse model to simulate the human lipid metabolism," Willnow explains. His team achieved this by breeding transgenic mice that produce human ApoE variants, either ApoE3 or ApoE4. The researchers then studied the lipid composition of the mice brains using mass spectrometry, a technique for analyzing atoms and molecules. They found that the lipid composition was healthy in the brain of mice with ApoE3 with adequate levels of unsaturated fatty acids and endocannabinoids. In contrast, the brain cells of the E4 mice did not receive enough lipids. Under the microscope, the researchers saw that in the ApoE4 mice the membrane vesicles that normally bring sortilin from the cell interior back to the cell surface had gotten stuck inside the neuron - a sign that ApoE4 had caused the receptor to clump up.

A potential new approach to Alzheimer's therapeutics

"This finding may provide the basis for a new strategy to treat Alzheimer's," Willnow says. People with the E4 variant could be treated with an agent that prevents ApoE4 from causing the receptor sortilin to clump up. Such agents are already being tested in neuron cultures.

Willnow's lab at the MDC, in collaboration with the Neuroscience Research Campus at Aarhus University in Denmark, is now working to develop such a therapeutic. The Novo Nordisk Foundation is supporting the research with a €7 million grant. "If we succeed in developing such a drug, screening for ApoE4 might make sense," the cell biologist says. Preventive measures could then be taken against the inflammatory damage of gray cells in people with a genetic risk. "But until then I'd rather not know what ApoE variant I have."

SOLOMONS, MD (June 23, 2020)--For the endangered Atlantic sturgeon and the commercially and recreationally important striped bass, the Delaware-Maryland-Virginia coastal shelf serves as an important spring and fall "flyway." Typically thought of as an established aerial route used by migratory birds to travel between feeding and breeding grounds, a recent study by scientists at the University of Maryland Center for Environmental Science applies the term to fish species of concern. Authors suggest that the development of wind farms on the Delmarva coastal shelf, 17-26 miles from Ocean City's shoreline, may alter the migratory behavior of these fish as new wind turbines in this otherwise featureless region could create habitat around which fish linger.

Studies within the Maryland Wind Energy Area--the coastal shelf waters leased by the Bureau of Ocean Energy Management for offshore wind farms--prior to construction activities reveal that Atlantic sturgeon and striped bass are frequent visitors. Seasonal trends lead scientists to believe that the wind energy area lies within an important migration corridor for both species. Atlantic sturgeon were most commonly observed moving through the area during the spring and fall, while striped bass had an increased migratory presence in spring and winter. The Atlantic sturgeons' "flyway" tended to favor shallower, warmer waters, while striped bass were more likely to be found at great depths and cooler conditions.

Both species spent longer periods of time in the corridor during the autumn and winter. This trend was particularly strong for striped bass, with many individuals prolonging their presence on the outer shelf during winter. However, during the summer, Atlantic sturgeon were rarely detected and striped bass were absent.

The construction of an off-shore wind farm creates loud noises and increased activity that can disrupt typical animal behaviors. The low occurrence of these important fish species during the summer months suggests a potential window for wind turbine construction, when impacts could be minimized.

"Scientists have learned a lot about the Atlantic sturgeon and striped bass' seasonal patterns of habitat selection within spawning rivers, estuaries, and shelf foraging habitats," says study author Ellie Rothermel, who recently received her master's degree from the University of Maryland Center for Environmental Science. "During these times, we know where the fish are likely to be and when to expect them there, but information on the location and timing of key coastal migrations is limited. Coastal waters have been largely inaccessible to scientists. Our study uses acoustic telemetry to understand the critical migratory periods in the lives of these fish species."

Rothermel compares acoustic telemetry to the E-ZPass system used for vehicles. When a car with E-ZPass is driven over the Bay Bridge, a toll booth collects its identification number, along with the time and date. Just like toll booths and the E-Z Pass system, scientists use acoustic receivers and tags to track where fish go, and when they go there.

After catching and determining the size, weight and sex of a striped bass, scientists surgically implanted an acoustic tag into the fish prior to releasing it. An acoustic tag is a small device, about the size of a thumb, that has a unique ID and makes a "ping" sound every few seconds.

Scientists also deployed 20 acoustic receivers in the Maryland Wind Energy Area. When a tagged fish swims past a receiver, a listening device about the size of a liter soda bottle, the receiver records the "ping" sent out by the tag. Each "ping" transmits its unique ID and the depth at which the fish was swimming to the receiver, which also records the time and date. The array of receivers allows scientists to monitor the movements of tagged fish. During the study, "pings" from 352 individual Atlantic sturgeon and 315 individual striped bass were recorded by receivers.

Scientists believe that Maryland's future offshore wind farm could become a stop-over region where striped bass and sturgeon might linger longer. The DelMarVa coastal shelf is a fairly barren area. The development of high relief wind turbines would provide structure around which fish may gather and linger during migrations.

"To extend the highway travel metaphor, the wind farm that will be built in the area off-shore from Ocean City may become a 'rest stop' where fish and sharks can grab a bite to eat and take a break before resuming their travels," says study co-author Dave Secor of the University of Maryland Center for Environmental Science.

As wind farms are developed and operated offshore of the Mid-Atlantic and Southern New England regions, which together comprises a multispecies "flyway," scientists could use the telemetry array design to monitor potential impacts. Cooperation among researchers, expanded scale of acoustic telemetry arrays, and increased incorporation of oceanographic data will improve understanding of how fishes will respond to wind energy development in the northwest Atlantic Ocean.

TALLAHASSEE, Fla. -- Thank goodness for the Earth's crust: It is, after all, that solid, outermost layer of our planet that supports everything above it.

But much of what happens below that layer remains a mystery, including the fate of sections of crust that vanish back into the Earth. Now, a team of geochemists based at the Florida State University-headquartered National High Magnetic Field Laboratory has uncovered key clues about where those rocks have been hiding.

The researchers provided fresh evidence that, while most of the Earth's crust is relatively new, a small percentage is actually made up of ancient chunks that had sunk long ago back into the mantle then later resurfaced. They also found, based on the amount of that "recycled" crust, that the planet has been churning out crust consistently since its formation 4.5 billion years ago -- a picture that contradicts prevailing theories.

Their research is published in the journal Science Advances.

"Like salmon returning to their spawning grounds, some oceanic crust returns to its breeding ground, the volcanic ridges where fresh crust is born," said co-author Munir Humayun, a MagLab geochemist and professor at Florida State's Department of Earth, Ocean and Atmospheric Science (EOAS). "We used a new technique to show that this process is essentially a closed loop, and that recycled crust is distributed unevenly along ridges."

In addition to Humayun, the research team included MagLab postdoctoral researcher Shuying Yang, lead author on the paper, and MagLab Geochemistry Group Director and EOAS Chair Vincent Salters.

The Earth's oceanic crust is formed when mantle rock melts near fissures between tectonic plates along undersea volcanic ridges, yielding basalt. As new crust is made, it pushes the older crust away from the ridge toward continents, like a super slow conveyer belt. Eventually, it reaches areas called subduction zones, where it is forced under another plate and swallowed back into the Earth.

Scientists have long theorized about what happens to subducted crust after being reabsorbed into the hot, high-pressure environment of the planet's mantle. It might sink deeper into the mantle and settle there, or rise back to the surface in plumes, or swirl through the mantle, like strands of chocolate through a yellow marble cake. Some of that "chocolate" might eventually rise up, re-melt at mid-ocean ridges, and form new rock for yet another millions-year-long tour of duty on the sea floor.

This new evidence supports the "marble cake" theory.

Scientists had already seen clues supporting the theory. Some basalts collected from mid-ocean ridges, called enriched basalts, have a higher percentage of certain elements that tend to seep from the mantle into the melt from which basalt is formed; others, called depleted basalts, had much lower levels.

To shed more light on the mystery of the disappearing crust, the team chemically analyzed 500 samples of basalt collected from 30 regions of ocean ridges. Some were enriched, some were depleted and some were in between.

Early on, the team discovered that the relative proportions of germanium and silicon were lower in melts of recycled crust than in the "virgin" basalt emerging from melted mantle rock. So they developed a new technique that used that ratio to identify a distinct chemical fingerprint for subducted crust.

They devised a precise method of measuring that ratio using a mass spectrometer at the MagLab. Then they crunched the numbers to see how these ratios differed among the 30 regions sampled, expecting to see variations that would shed light on their origins.

At first the analysis revealed nothing of note. Concerned, Yang, a doctoral candidate at the time, consulted with her adviser. Humayun suggested looking at the problem from a wider angle: Rather than compare basalts of different regions, they could compare enriched and depleted basalts.

After quickly re-crunching the data, Yang was thrilled to see clear differences among those groups of basalts.

"I was very happy," recalled Yang, lead author on the paper. "I thought, 'I will be able to graduate!'"

The team had detected lower germanium-to-silicon ratios in enriched basalts -- the chemical fingerprint for recycled crust -- across all the regions they sampled, pointing to its marble cake-like spread throughout the mantle. Essentially, they solved the mystery of the vanishing crust.

It was a lesson in missing the forest for the trees, Humayun said.

"Sometimes you're looking too closely, with your nose in the data, and you can't see the patterns," he said. "Then you step back and you go, 'Whoa!'"

Digging deeper into the patterns they found, the scientists unearthed more secrets. Based on the amounts of enriched basalts detected on global mid-ocean ridges, the team was able to calculate that about 5 to 6 percent of the Earth's mantle is made of recycled crust, a figure that sheds new light on the planet's history as a crust factory. Scientists had known the Earth cranks out crust at the rate of a few inches a year. But has it done so consistently throughout its entire history?

Their analysis, Humayun said, indicates that, "The rates of crust formation can't have been radically different from what they are today, which is not what anybody expected."

Workplace gender bias is being kept alive by people who think it's no longer an issue, new research suggests.

In the study, managers were given identical descriptions of a worker - the only difference being either a male or female name.

Most managers rated the male worker as more competent, and recommended a higher salary - an average 8% pay gap.

The "key drivers" of this gap were managers who thought bias no longer existed in their profession, while those who believed bias still existed recommended roughly equal pay.

This means holding this belief constitutes a "critical risk factor", and may be vital to identifying who in a profession is perpetuating issues of gender bias.

Two thirds of the managers who thought gender bias no longer existed were men - but female managers with this opinion undervalued female staff just as much as male managers did.

The research -by the University of Exeter, Skidmore College and the British Veterinary Association (BVA) - focussed on the veterinary profession.

"Managers who thought gender bias is no longer an issue recommended annual pay that was £2,564 ($3,206) higher for men than for women," said lead author Dr Christopher Begeny, of the University of Exeter.

"This represents an 8% gap - which closely matches the real pay gap we see in veterinary medicine.

"When you break this down, it's like going to that male employee after an hour's work and saying, 'ya know what, here's an extra two bucks - not because you're particularly qualified or good at your job, but simply because you're a man'.

"And then the next hour, you go back and give that male employee another $2, and the next hour another $2.

"And on and on, continuing to do that every hour for the next 2,000 hours of work."

The research was made up of two studies.

The first asked vets about their experiences, and showed women were more likely than men to report experiencing discrimination, and less likely to experience recognition among colleagues for their value and worth.

In the second study, managers participated in a randomised double-blind experiment, with the stated purpose of "understanding their experiences managing others".

They were each given a fictitious performance review for a veterinary surgeon.

Everyone was given an identical performance review, except that the name of the vet differed: either Mark or Elizabeth.

Managers evaluated the vet's performance/competence and indicated the salary they would advise if this employee was in their own practice.

"The resulting evaluations were systematically biased among those who thought gender bias was no longer an issue," said co-author, Professor Michelle Ryan, of the University of Exeter.

"Unsurprisingly, these biased evaluations led to lower pay recommendations for female vets.

"We have worked closely with the BVA, and when presenting these findings to managers in the veterinary profession they are often shocked and concerned."

The studies also found:

- Vets were split over whether gender bias still existed in their profession (44% said yes, 42% said no; the rest were undecided).

- Gender bias among managers who thought bias was not an issue was not only evident among those who strongly believed this, but also those who only slightly held this view.

- Because of seeing the female as less competent, managers were also less likely to advise giving her more managerial responsibilities, and less likely to encourage her to pursue important opportunities for promotion. This shows how managers' biases not only affect women's current employment situation (current pay) but can affect the entire trajectory of their career, by discouraging them from pursuing promotions.

- All of these effects held true when controlling for managers' own gender, their years of managerial experience, how long they've been in the profession, etc.

- They also held true when controlling for managers' endorsement of more overtly sexist beliefs (i.e., endorsement of hostile sexism)

Women have outnumbered men in the veterinary profession for more than a decade, so biased perceptions of women lacking competence might be expected to have disappeared.

The bias shown in this study may be a harbinger of what's to come in other professions - those that are striving to increase women's representation, perhaps thinking, erroneously, that this will resolve any issues of gender bias.

"With many professions working to increase the number of women in their ranks, companies need to be careful not to equate gender diversity with gender equality - even with equal numbers you can have unequal treatment," said Dr Begeny.

"There is no 'silver bullet' to ensure gender equality has been achieved.

"Ongoing vigilance is required, including awareness training to guard against some forms of bias.

"It is also important to have 'guardrails' that help prevent discrimination, including by removing names from job applications, which can signal the applicant's gender, and ensuring standard questions in interviews."

Dr Begeny added: "Overall, this research highlights a rather insidious paradox that can arise when individuals misperceive the level of progress made on gender equality in their profession, such that those who mistakenly think gender bias is no longer an issue become the highest risk for perpetuating it."

Fires have spread across the majority of the landscape in Angola and the Democratic Republic of the Congo in this NOAA/NASA Suomi NPP satellite image using the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument from June 25, 2020. Fires of this number are not uncommon at this time of year in Africa. During the agricultural season of clearing field and planting new ones, farmers set fire to the remains of old crop fields to rid them of the leftover grasses and scrub. This action also helps return nutrients to the soil to ensure a good crop during the next planting season. This agricultural ritual is one that is at least 12,000 years ago. It is economical for the farmer since large equipment is not needed to clear the fields. In Angola, the Global Forest Watch website (using data from the VIIRS instrument on the Suomi NPP satellite) had 61,661 alerts for fires for the past week (June 18 - June 25). In the Democratic Republic of the Congo there are 102,738 VIIRS alerts for fire for that same period.

"Slash and burn" agriculture is practiced most often in regions including parts of Africa, northern South America, and Southeast Asia, where an abundance of grasslands and rainforests are found. While fire helps enhance crops and grasses for pasture, the fires also produce smoke that degrades air quality. The smoke released by any type of fire (forest, brush, crop, structure, tires, waste or wood burning) is a mixture of particles and chemicals produced by incomplete burning of carbon-containing materials. All smoke contains carbon monoxide, carbon dioxide and particulate matter or soot and is hazardous to breathe.

New research has revealed for the first time that shield bugs use a variety of colours throughout their lives to avoid predators.

Shield bugs are often bright, colourful insects that use colours to warn off their distastefulness to predators. The paper, published in Proceedings of the Royal Society B, found that it is impossible to predict how an adult bug will look like based on their colour when young.

"We found that in most species, the same individual bug will use different colour combinations as nymphs - young bugs - and adults, going for example from red and green to yellow and green," said lead author and ecologist, Dr Iliana Medina, from the University of Melbourne's School of Biosciences.

"This is significant because many of these species use colour to warn predators that they are distasteful, and for years it has been thought that animals living in the same environment - like nymphs and adults of the same species - should use similar warning colours, not different ones."

The joint research between scientists at the University of Melbourne and the Australian National University combined information on colour in young and adults for more than 100 species of shield bugs worldwide. They then used field work in Canberra, with white-winged choughs, to measure how likely these birds were to attack adult and nymphs of one Australian species of shield bug, the cotton harlequin bug.

Experiments were also conducted in the aviary, training two-week-old chicks to see how fast they learned to avoid nymphs and adults, then testing whether their previous experience with adults could reduce attack rates on nymphs.

"Our experiments with the cotton harlequin bug showed that predators could quickly learn to avoid both types of colour signals from nymphs and adults, but nymphs get a larger benefit," Dr Medina said.

"Although young and adult cotton harlequin bugs have different colours, previous experience with adults make chicks less likely to attack the nymphs. Also, chicks and wild predators that have never seen the insects before do not show much interest in eating them. The colours in these insects are a great strategy against predators."

Many animals such as frogs, insects and sea slugs use bright colourations to advertise toxicity or distastefulness. In theory, warning signals of prey that live in the same environment should be the same because predators can learn more effectively to avoid one type of pattern, instead of many different ones.

While this idea has been used to explain the great examples of mimicry in nature, and why distantly related species end up having the same warning colours, such as black and red, or black and yellow, researchers say there are multiple examples of variation in local warning signals and an overlooked type of variation is that across life stages.

"If predators were able to learn to avoid only one type of warning colour, we would expect nymphs and adults to look similar in many species," Dr Medina said. "What our findings show, however, is that the wide colour variation in shield bugs is probably the result of predators being able to learn to avoid different types of colourful signals."

The importance of light-based technologies for our society was demonstrated once more in recent weeks. Thanks to the internet, millions of people can work remotely, enter virtual classrooms, or talk to friends and relatives. The internet, in turn, owes its power to countless light pulses with which enormous amounts of data are sent around the globe via optical fibres.

To steer and control these light pulses, various technologies are employed. One of the oldest and most important is the diffraction grating, which deflects light of different colours in precisely determined directions. For decades, scientists have been trying to improve the design and production of diffraction gratings to make them suitable for today's demanding applications. At ETH Zurich, a group of researchers led by David Norris, professor at the Department of Mechanical and Process Engineering, have developed a completely new method by which more efficient and more precise diffraction gratings can be produced. They did this together with colleagues now at the University of Utrecht and the company Heidelberg Instruments Nano, which was founded as ETH spin-off SwissLitho. The researchers published the results in the scientific journal Nature.

Interference through grooves

Diffraction gratings are based on the principle of interference. When a light wave hits a grooved surface, it is divided into many smaller waves, each emanating from an individual groove. When these waves leave the surface, they can either add together or cancel each other, depending on the direction in which they travel and on their wavelength (which is related to their colour). This explains why the surface of a CD, on which data is stored in tiny grooves, generates a rainbow of reflected colours when it is illuminated by white light.

For a diffraction grating to work properly its grooves need to have a separation similar to the wavelength of the light, which is around one micrometre - a hundred times smaller than the width of a human hair. "Traditionally, those grooves are etched into the surface of a material using manufacturing techniques from the microelectronics industry", says Nolan Lassaline, a PhD student in Norris's group and first author of the study. "This means, however, that the grooves of the grating are rather square in shape. On the other hand, physics tells us that we should have grooves with a smooth and wavy pattern, like ripples on a lake." Grooves made with traditional methods can, therefore, only ever be rough approximations, which in turn means that the diffraction grating will steer light less efficiently. By pursuing a completely new approach Norris and his collaborators have now discovered a solution to that problem.

Surface patterning with a hot probe

Their approach is based on a technology that also has its origins in Zurich. "Our method is a great-grandchild of the scanning tunnelling microscope, which was invented almost forty years ago by Gerd Binnig and Heinrich Rohrer, who would later win the Nobel Prize for their work", says Norris. In such a microscope, material surfaces are scanned by the sharp tip of a probe with high resolution. The images resulting from such a scan can even show the individual atoms of a material.

Conversely, however, one can also use the sharp tip to pattern a material and thus produce wavy surfaces (see picture). To do so, the researchers heat the tip of a scanning probe to almost 1000 degrees centigrade and press it into a polymer surface at certain locations. This causes the molecules of the polymer to break up and evaporate at those locations, allowing the surface to be precisely sculpted. In this way, the scientists can write almost arbitrary surface profiles point by point into the polymer layer with a resolution of a few nanometres. Finally, the pattern is transferred to an optical material by depositing a silver layer onto the polymer. The silver layer can then be detached from the polymer and used as a reflective diffraction grating.

"This allows us to produce arbitrarily shaped diffraction gratings with a precision of just a few atomic distances in the silver layer", says Norris. Unlike traditional square-shaped grooves, such gratings are no longer approximations, but practically perfect and can be shaped in such a way that the interference of the reflected light waves create precisely controllable patterns.

A variety of applications

Such perfect gratings enable new possibilities for controlling light, which has a range of applications, says Norris: "The new technology can be used, for instance, to build tiny diffraction gratings into integrated circuits with which optical signals for the internet can be sent, received and routed more efficiently." Lassaline adds, "Generally, we can use such diffraction gratings to make highly miniaturized optical devices such as on-chip micro-lasers." Those miniaturized devices, he says, range from ultrathin camera lenses to compact holograms with sharper images. They promise a broad impact in optical technologies such as futuristic smartphone cameras, biosensors, or autonomous vision for robots and self-driving cars.

"Through a counterfactual analysis, we showed that between 1986 and 2011 the incentives to afforestation in Chile caused an increase in forest plantations, but reduced the extent of native forests", explains the academic from the Faculty of Forest Sciences at the Universidad de Concepción, UdeC, Dr. Cristian Echeverría, about the main conclusions of the paper Impacts of Chilean forest subsidies on forest cover, carbon and biodiversity, published by the journal Nature Sustainability, co-written with academicians Robert Heilmayr from the U. of California, and Eric F. Lambin of Stanford University, both from the United States.

For the UdeC researcher, this international collaboration was of the "highest scientific standard, with great strictness and close cooperation in the stages of formulation of the idea, preparation of the manuscript and data analysis", he sustains and explains that the idea of the study emerged "about seven years ago, when the other authors got interested in my research related to deforestation in Chile. After publishing a joint paper about land use changes in Chile, we decided to continue the collaboration between the Landscape Ecology Laboratory, LEP, and U. Stanford to answer new scientific questions"

In the same way, the study -which aims to assess the impacts of an incentive to afforestation on carbon sequestration, forest cover and biodiversity- was possible thanks to various sources of financing and information, given that "having classified maps of satellite images was an immense task of the three universities", says Echeverría, adding that they had "financing from various Fondecyt projects and from the LEP's own resources and other funds obtained by the leading author, Robert Heilmayr, during his PhD studies", he details.

Regarding the main scientific conclusions of the recent study, Echeverría details that the increasing establishment of exotic plantations caused "small negative impacts on the total carbon stored in the above-ground biomass. Additionally, the policy produced the substitution of native forests for plantation which resulted in a significant decrease in the richness of species of flora and fauna".

In the researcher's opinion, based on the results of this study, it is possible to "strengthen research in the evaluation of the impact of environmental policies on other components, such as, for example, ecosystem services; evaluating current policies on native forests and other environmental matters; identifying the most critical areas of biodiversity loss for the design of restoration plans. In addition, contributing with new evidence on the future impacts that the NdC (Nationally Determined Contributions) of Chile would have on the design of mitigation measures and adaptation to climate change".

"The reforestation and restoration policies that the country is currently pursuing need to be carefully designed and firmly applied to ensure the protection of natural ecosystems. Such safeguards can improve the benefits of a policy, as well as its impacts on carbon sequestration and biodiversity conservation", states the UdeC academician.

An international team of researchers, affiliated with UNIST has unveiled a novel material that could enable major leaps in the miniaturization of electronic devices. Published in the prestigious journal Nature, this study represent a significant achievement for future electronics.

This breakthrough comes from a research, conducted by Professor Hyeon Suk Shin (School of Natual Sciences, UNIST) and Principal Researcher Dr. Hyeon-Jin Shin from Samsung Advanced Institute of Technology (SAIT), in collaboration with Graphene Flagship researchers from University of Cambridge (UK) and Catalan Institute of Nanoscience and Nanotechnology (ICN2, Spain).

In this study, the team successfully demonstrated the synthesis of thin film of amorphous boron nitride (a-BN) with extremely low dielectric constant as well as high breakdown voltage and superior metal barrier properties. The research team noted that this newly fabricated material has great potential as interconnect insulators in the next-generation of electronic circuits.

In the ongoing process of miniaturization of logic and memory devices in electronic circuits, minimizing the dimensions of interconencts - metal wires that link the different device components on the chip - is crucial to guarantee improved performance and faster response of the device. Extensive research efforts have been devoted to decreasing the resistance of scaled interconnects because integration of dielectrics using complementary metal oxide semiconductor (CMOS) compatible processes has proven to be exceptionally challenging. According to the research team, the required interconnect isolation materials should not only possess low relative dielectric constants (referred to as k-values), but should also be thermally, chemically, and mechanically stable.

There has been an ongoing quest to obtain materials with ultra-low-k (relative permittivity around or below 2) avoiding the artificial addition of pores in the thin film in the semiconductor industry for at least the past 20 years. Several attempts had been made to develop materials with desired characteristics, yet those materials have failed to be successfully integrated in interconnects due to poor mechanical properties or poor chemical stability upon integration, causing reliability failures.

In this study, the joint research has succeeded in demonstrating a Back-End-ofthe-Line (BEOL) compatible approach to grow amorphous boron nitride (a-BN) with extremely low-k dielectrics. In particular, they synthesized approximately 3 nm thin a-BN on a Si substrate, using low temperature remote inductively coupled plasma-chemical vapour deposition (ICP-CVD). The resulting material showed an extremely low dielectric constant in the range of 1.78, which is 30% lower than the dielectric constant of currently available insulators.

In this study, the joint research has succeeded in demonstrating a Back-End-ofthe-Line (BEOL) compatible approach to grow amorphous boron nitride (a-BN) with extremely low-k dielectrics. In particular, they synthesized approximately 3 nm thin a-BN on a Si substrate, using low temperature remote inductively coupled plasma-chemical vapour deposition (ICP-CVD). The resulting material showed an extremely low dielectric constant in the range of 1.78, which is 30% lower than the dielectric constant of currently available insulators.

"We found that temperature was the most important parameter with ideal a-BN film deposition occurring at 400° C," says Seokmo Hong in the Doctoral program of Natural Sciences, the first author of the study. "This material with ultra-low-k also manifests a high breakdown voltage and likely superior metal barrier properties, making the film very attractive for practical electronic applications."

Angle-dependent near-edge X-ray absorption fine structure (NEXAFS) measured in partial electron-yield (PEY) mode at Pohang Light Source-II 4D beam line was also used to investigate the chemical and electronic structures of a-BN. Their findings indicated that the irregular, random atomic arrangement causes the dielectric constant value to drop.

The new material also manifests excellent mechanical properties of high strength. Moreover, when researchers tested the diffusion barrier properties of a-BN in very harsh conditions, they found it can prevent metal atom migration from the interconnects into the insulator. This result will help resolves a long-standing issue of interconnects in CMOS integrated circuit fabrication, enabling further miniaturaization of electronic devices.

"Development of electrically, mechanically and thermally robust low-k materials (k

"Our results demonstrate that the amorphous counterpart of two-dimensional hexagonal BN possesses the ideal low-k dielectric characteristics for high-performance electronics," says Professor Shin. "If they are commercialized, it will be a great help in overcoming the crisis looming over the semiconductor industry."

Eating a Late Meal May Be Harmful To Your Metabolic Health, Particularly For Early Birds

People have anecdotally claimed that the timing of a meal may affect metabolism, but there isn't much solid evidence in support. To see how timing of eating influences metabolism, Johns Hopkins Medicine researchers studied 20 healthy volunteers by giving them a meal at a traditional hour (6 p.m.) or a meal at a later time of the day (10 p.m.). They found that when people ate later, they had higher spikes in blood sugar, slower fat breakdown and even increases in the stress hormone cortisol, believed to be a factor in promoting weight gain. When they looked more closely at different responses to the late meal, they found that people who normally went to bed early -- so-called "early birds" -- experienced an even bigger impact from eating late.

In their findings published on June 11, 2020, in the Journal of Clinical Endocrinology & Metabolism, the researchers say eating late could promote obesity if these conditions happen often enough.

"What time you eat could be just as important as what you eat when it comes to metabolic health," says Jonathan Jun, M.D., associate professor of medicine at the Johns Hopkins University School of Medicine. "When people eat identical meals at two different times, their bodies apparently process those calories differently. How an individual responds depends on their particular biorhythms and sleep behaviors."

For the study, each participant was given a "routine-time" dinner at 6 p.m. or a late dinner at 10 p.m., and drank a beverage containing a non-radioactive tracer that allowed the researchers to follow fat burning in the body. All participants went to bed at 11 p.m. Each participant had an intravenous line, which allowed researchers to take blood samples during the day and overnight without interrupting or waking them.

Just after a late dinner, participants had on average an 18% higher blood sugar spike and a 5% increase in cortisol levels. Furthermore, the fat in the late meal burned slower, resulting in a 10% reduction in fat breakdown by the next morning.

The researchers then looked at how each participant's body responded to the late meal based on their normal habits or daily rhythms. Among the "early birds," who were accustomed to an 11 p.m. bedtime, blood sugar levels rose 30% higher while the fat in their meals burned 20% less by the next morning.

The people who typically went to bed between 2 a.m. and 3 a.m. -- the so-called "night owls" -- were barely affected by the late meal.

Because they only looked at what happens after eating one late meal, the researchers say they aren't sure if continually eating late will eventually allow the body to adapt. They also say it's unclear if this slower metabolism after a late meal is caused by how soon a person goes to sleep after they eat, or if it results from each person's natural variations in metabolism over a 24-hour period (their circadian rhythm).

The researchers plan to investigate these concepts in future studies.

Study Says Women Underrepresented As Leaders in Academic Hospital Medicine Programs

Media Contact: Marin Hedin, mhedin2@jhmi.edu

In recent years, the number of women who entered U.S. medical school surpassed the number of men. But gender inequities still exist in many areas of medicine, Johns Hopkins researchers report in a paper published March 3, 2020, in the Journal of General Internal Medicine. Of academic hospital medicine programs, the report states, 79% are run by men and male hospitalist leaders are more likely to have attained the rank of full professor than women leaders.

"Despite making a number of strides in medicine when it comes to gender bias, this is an area where we still haven't reached full equality," says Carrie Herzke, M.D., assistant professor of medicine and associate vice chair for clinical affairs in the Department of Medicine at the Johns Hopkins University School of Medicine.

For the study, which was done in collaboration with the Society of Hospital Medicine, Herzke and her colleagues conducted a survey of all U.S. academic hospital programs associated with the Association of American Medical Colleges. After identifying 135 programs, surveys were sent electronically to academic hospitalist leaders at each one. Questions asked about the leader's gender, the program's size and organization, faculty characteristics, and perceptions about promotion and faculty development.

Of the 135 programs, 80 (59%) responded to the survey. The data showed that these programs did not differ significantly from nonresponding programs in terms of funding, region, age or type of institution. However, while the programs reported approximately equal numbers of male and female faculty members, 79% of their directors were male. Moreover, 37% of male hospitalist leaders were full professors, while no female hospitalist leaders held that rank.

Herzke and her colleagues plan more research to look at promotion and faculty development in academic hospital medicine. Also, they plan similar studies to understand if there are issues with racial inequity among leadership in academic hospital medicine. This topic in particular, says Herzke, is incredibly important to evaluate and, if inequality exists, address.

Immune Cells Hampered When Fighting Soft Tissue and Bone Sarcomas

Media Contact: Valerie Mehl, mehlva@jhmi.edu

Immunotherapies such as checkpoint inhibitors that enhance the body's natural ability to fight cancer have been only minimally successful in treating sarcomas -- rare cancers that grow in the soft tissues and bones. In a new study, Johns Hopkins Kimmel Cancer Center researchers have teased out the tumor microenvironment in these cancers to look for reasons why.

The work was published online on June 16, 2020, in the journal Clinical Cancer Research.

Studying human samples from two types of soft tissue cancers -- rhabdomyosarcomas and undifferentiated pleomorphic sarcomas (UPS) -- with different genetic underpinnings and responses to immunotherapy, investigators discovered that both tumor types were ripe with tumor-associated macrophages (TAMs). Heavily involved in promoting tumor initiation and growth, TAMs hamper the proper immune reaction against tumors. Additionally, both sarcomas had similar amounts of CD8+ T lymphocytes (CD 8+ T cells, also known as "killer T cells"), immune system cells that protect the body from infection and are believed to be among the front-line soldiers in the fight against cancers.

In their study, the researchers discovered that where the CD8+ T cells congregated and how their antitumor functions were impeded by TAMs differed in the two sarcomas.

In UPS, the researchers found that the tumors themselves were filled with TAMs and CD8+ T cells. With constant stimulation by tumor antigens, CD8+ cells produce large amounts of PD-1, a protein that eventually exhausts the T cell population. When this happens, the researchers suggest, and TAMs control the environment, normal T cell activity against the cancer is suppressed.

In rhabdomyosarcomas, the researchers found CD8+T cells only within tiny aggregates of immune cells called tertiary lymphoid structures (TLSs). TLSs are known to play a major role in initiating antitumor immune responses, helping the immune system recognize cancer cells as targets.

"Our working theory is that TAMs around the TLSs restrain them from deploying the T cells they contain into the surrounding tumor tissue," says senior study author and pediatric hematologist-oncologist Nicolas Llosa, M.D., assistant professor of oncology at the Johns Hopkins University School of Medicine.

Llosa says the study findings suggest that for UPS and rhabdomyosarcoma, targeting and shutting down TAMs and in turn, restoring the activity of fully potent, cancer-fighting T cells on tumors, may be the key to achieving a positive outcome against this disease.

"We are really trying to learn as much as we can about the granular details of immune cell interactions in sarcomas," Llosa says. "This is a rare subset of patients who are in desperate need of new treatments. The therapies for sarcomas have not changed in the past four decades."

Immunotherapy has had limited success in treating some sarcomas, he says, but no effect so far for UPS and rhabdomyosarcoma.

"The basis of successful immunotherapy lies in the ability of the immune system to recognize cancer as foreign and attack, and is dependent on genetics, host and environmental factors, and makeup of the tumor microenvironment," says Llosa. "We need to understand the immune niche that sustains these tumors and how it supports tolerance, so we can determine what drug targets could be used to help mount a better response."

Scientists from Staffordshire University claim that new 3D printed insoles can significantly improve the foot health of people suffering with diabetes.

This study offers hope for millions of patients with diabetes who are at risk of developing foot ulcers, which in many cases end up in amputation. It presents the first quantitative evidence in support of optimised cushioning in diabetic footwear as part of standard clinical practice.

In their latest paper ['Optimised cushioning in diabetic footwear can significantly enhance their capacity to reduce plantar pressure'] published in Gait and Posture, researchers conclude that selecting the correct cushioning stiffness in footwear can significantly reduce pressures experienced on the feet which can lead to ulcers and other painful complications.

In the study carried out in Malta, 15 participants with diabetic foot disease were asked to walk in footwear fitted with made to measure 3D-printed insoles designed by the Centre for Biomechanics and Rehabilitation Technologies (CBRT) at Staffordshire University. These footbeds were used to change the stiffness of the entire sole across a spectrum of very soft to very stiff.

Dr Chatzistergos, Associate Professor at CBRT and the lead author of ths study said: "The optimum stiffness is clearly related to the patient's body mass index (BMI). This study adds to our earlier findings and concludes that stiffer materials are needed for people with a higher BMI."

Collaborators Dr Alfred Gatt and Dr Cynthia Formosa from the University of Malta and Visiting Fellows at CBRT provided clinical support for this study and led the experiments in Malta. Dr Gatt noted: "We hope that the results reported within this study will generate interest amongst all professionals managing this debilitating condition."

Further work is now underway to develop a method to help professionals identify the optimum cushioning stiffness on a patient-specific basis. Professor Nachi Chockalingam, Director of CBRT and a co-inventor of the technology said "With numerous patients losing their limbs to diabetic foot disease, our research will help clinicians effectively manage this disease."