Tech

Physicists discovered a novel kind of nanotube that generates current in the presence of light. Devices such as optical sensors and infrared imaging chips are likely applications, which could be useful in fields such as automated transport and astronomy. In future, if the effect can be magnified and the technology scaled up, it could lead to high-efficiency solar power devices.

Working with an international team of physicists, University of Tokyo Professor Yoshihiro Iwasa was exploring possible functions of a special semiconductor nanotube when he had a lightbulb moment. He took this proverbial lightbulb (which was in reality a laser) and shone it on the nanotube to discover something enlightening. Certain wavelengths and intensities of light induced a current in the sample -- this is called the photovoltaic effect. There are several photovoltaic materials, but the nature and behavior of this nanotube is cause for excitement.

"Essentially our research material generates electricity like solar panels, but in a different way," said Iwasa. "Together with Dr. Yijin Zhang from the Max Planck Institute for Solid State Research in Germany, we demonstrated for the first time nanomaterials could overcome an obstacle that will soon limit current solar technology. For now solar panels are as good as they can be, but our technology could improve upon that."

The current-inducing nanotube is made from rolled-up sheets of a special semiconductor material based on tungsten disulfide (WS2). The sheets do not induce a current in the presence of light unless rolled into tubes. This is an emergent behavior, one not intrinsic to the material until it's modified. What is interesting is how it differs from existing photovoltaic materials.

Generally, photovoltaic solar panels make use of a certain arrangement of materials called a p-n junction. This is where two different kinds of materials (p-type and n-type) are attached, which alone do not generate a current in the presence of light, but when placed together, do. P-n junction-based photovoltaics have improved in efficiency over the 80 years or so since their discovery. However, they are getting close to their theoretical limits due in part to their need for the arrangement of multiple materials.

WS2 nanotubes do not rely on a junction between materials to gain the photovoltaic effect. When exposed to light, they generate a current throughout their entire structure or bulk. This is called the bulk photovoltaic effect (BPVE) and it occurs as the WS2 nanotube is not symmetrical if you were to reverse it. If it were symmetrical, the current induced would not have a preferred direction and thus would not flow. So other symmetrical nanotubes -- such as the famous carbon nanotubes -- don't exhibit BPVE despite being great electrical conductors.

"Our research shows an entire order of magnitude improvement in efficiency of BPVE compared to its presence in other materials," continued Iwasa. "But despite this huge gain, our WS2 nanotube cannot yet compare to the generating potential of p-n junction materials. This is because the device is nanoscopic and will be difficult to make larger. But it is possible and I hope chemists are inspired to take on that challenge."

In the long term, researchers hope this kind of material could allow fabrication of more efficient solar panels. But given the foreseeable size constraints in the near term, it's more likely to find use in other applications. BVPE could be used to create more sensitive and higher-fidelity optical or infrared sensors. These have further applications in embedded monitoring devices, sensor-laden self-driving cars or even in the imaging sensors for astronomical telescopes.

"My colleagues from around the world and I eagerly explore the potential of this unprecedented technology," concluded Iwasa. "For me, the idea of creating new materials beyond anything nature could provide is a fascinating reward in its own right."

PITTSBURGH--Computer vision researchers have demonstrated they can use special light sources and sensors to see around corners or through gauzy filters, enabling them to reconstruct the shapes of unseen objects.

The researchers from Carnegie Mellon University, the University of Toronto and University College London said this technique enables them to reconstruct images in great detail, including the relief of George Washington's profile on a U.S. quarter.

Ioannis Gkioulekas, an assistant professor in Carnegie Mellon's Robotics Institute, said this is the first time researchers have been able to compute millimeter- and micrometer-scale shapes of curved objects, providing an important new component to a larger suite of non-line-of-sight (NLOS) imaging techniques now being developed by computer vision researchers.

"It is exciting to see the quality of reconstructions of hidden objects get closer to the scans we're used to seeing for objects that are in the line of sight," said Srinivasa Narasimhan, a professor in the Robotics Institute. "Thus far, we can achieve this level of detail for only relatively small areas, but this capability will complement other NLOS techniques."

This work was supported by the Defense Advanced Research Project Agency's REVEAL program, which is developing NLOS capabilities. The research will be presented today at the 2019 Conference on Computer Vision and Pattern Recognition (CVPR2019) in Long Beach, California, where it has received a Best Paper award.

"This paper makes significant advances in non-line-of-sight reconstruction -- in essence, the ability to see around corners," the award citation says. "It is both a beautiful paper theoretically as well as inspiring. It continues to push the boundaries of what is possible in computer vision."

Most of what people see -- and what cameras detect -- comes from light that reflects off an object and bounces directly to the eye or the lens. But light also reflects off the objects in other directions, bouncing off walls and objects. A faint bit of this scattered light ultimately might reach the eye or the lens, but is washed out by more direct, powerful light sources. NLOS techniques try to extract information from scattered light -- naturally occurring or otherwise -- and produce images of scenes, objects or parts of objects not otherwise visible.

"Other NLOS researchers have already demonstrated NLOS imaging systems that can understand room-size scenes, or even extract information using only naturally occurring light," Gkioulekas said. "We're doing something that's complementary to those approaches -- enabling NLOS systems to capture fine detail over a small area."

In this case, the researchers used an ultrafast laser to bounce light off a wall to illuminate a hidden object. By knowing when the laser fired pulses of light, the researchers could calculate the time the light took to reflect off the object, bounce off the wall on its return trip and reach a sensor.

"This time-of-flight technique is similar to that of the lidars often used by self-driving cars to build a 3D map of the car's surroundings," said Shumian Xin, a Ph.D. student in robotics.

Previous attempts to use these time-of-flight calculations to reconstruct an image of the object have depended on the brightness of the reflections off it. But in this study, Gkioulekas said the researchers developed a new method based purely on the geometry of the object, which in turn enabled them to create an algorithm for measuring its curvature.

The researchers used an imaging system that is effectively a lidar capable of sensing single particles of light to test the technique on objects such as a plastic jug, a glass bowl, a plastic bowl and a ball bearing. They also combined this technique with an imaging method called optical coherence tomography to reconstruct the images of U.S. quarters.

In addition to seeing around corners, the technique proved effective in seeing through diffusing filters, such as thick paper.

The technique thus far has been demonstrated only at short distances -- a meter at most. But the researchers speculate that their technique, based on geometric measurements of objects, might be combined with other, complementary approaches to improve NLOS imaging. It might also be employed in other applications, such as seismic imaging and acoustic and ultrasound imaging.

In addition to Narasimhan, Gkioulekas and Xin, the research team included Aswin Sankaranarayanan, assistant professor in CMU's Department of Electrical and Computer Engineering; Sotiris Nousias, a Ph.D student in medical physics and bioengineering at University College London; and Kiriakos N. Kutulakos, a professor of computer science at the University of Toronto.

A new study shows how marine life around Antarctica returned after the extinction event that wiped out the dinosaurs.

A team led by British Antarctic Survey studied just under 3000 marine fossils collected from Antarctica to understand how life on the sea floor recovered after the Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago. They reveal it took one million years for the marine ecosystem to return to pre-extinction levels. The results are published today (19 June 2019) in the journal Palaeontology.

The K-Pg extinction wiped out around 60% of the marine species around Antarctica, and 75% of species around the world. Victims of the extinction included the dinosaurs and the ammonites. It was caused by the impact of a 10 km asteroid on the Yucatán Peninsula, Mexico, and occurred during a time period when the Earth was experiencing environmental instability from a major volcanic episode. Rapid climate change, global darkness, and the collapse of food chains affected life all over the globe.

The K-Pg extinction fundamentally changed the evolutionary history of life on Earth. Most groups of animals that dominate modern ecosystems today, such as mammals, can trace the roots of their current success back to the aftermath of this extinction event.

A team of scientists from British Antarctic Survey, the University of New Mexico and the Geological Survey of Denmark & Greenland show that in Antarctica, for over 320,000 years after the extinction, only burrowing clams and snails dominated the Antarctic sea floor environment. It then took up to one million years for the number of species to recover to pre-extinction levels.

Author Dr Rowan Whittle, a palaeontologist at British Antarctic Survey says:

"This study gives us further evidence of how rapid environmental change can affect the evolution of life. Our results show a clear link in the timing of animal recovery and the recovery of Earth systems."

Author Dr James Witts, a palaeontologist at University of New Mexico says:

"Our discovery shows the effects of the K-Pg extinction were truly global, and that even Antarctic ecosystems, where animals were adapted to environmental changes at high latitudes like seasonal changes in light and food supply, were affected for hundreds of thousands of years after the extinction event."

Postural sway is an independent risk factor for bone fractures in postmenopausal women, according to a new study from the University of Eastern Finland and Kuopio University Hospital. Women with the highest postural sway had a two times higher fracture risk compared to women with the lowest postural sway.

In addition, a combination of high postural sway and low bone mineral density was associated with a five times higher overall fracture risk and an 11 times higher osteoporotic fracture risk. The results were published in Journal of Bone and Mineral Research.

Postural sway is the tendency of the human body to sway while standing in an erect posture. Studying postural sway is important because it has shown an association with falls, which in turn are an important risk factor for fractures. Fracture risk estimation tools like FRAX (Fracture Risk Assessment Tool, University of Sheffield) use multiple fracture risk factors in order to estimate the chance of a fracture occurring over a certain period. However, the role of postural sway as an independent fracture risk factor has been uncertain.

"Our aim was to investigate the association between high postural sway and fractures. In addition, we wanted to study the combined effect of high postural sway and low bone mineral density on fracture risk," says Early Stage Researcher Sarang Qazi, the first author of the new study.

The study was based on the OSTPRE (Kuopio Osteoporosis Risk Factor and Prevention Study) cohort which was initiated in 1989 in order to study bone mineral loss, falls and fractures in postmenopausal women. The cohort consisted of 14,220 peri- and postmenopausal women living in Kuopio, in the eastern part of Finland. Postural sway was measured in 1,568 women from the cohort during 1994-97. The women were followed up for a period of 15 years. At the end of the follow-up period, fracture data were collected through study questionnaires and hospital records.

According to the results, women with the highest postural sway had a two times higher risk for any fracture and for osteoporotic wrist, upper arm, spine or hip fracture compared to women with the lowest postural sway. Further, a combination of high postural sway and low bone mineral density resulted in a five times higher overall fracture risk and an 11 times higher osteoporotic fracture risk compared to the low-risk group. Higher weight was also a significant fracture risk factor.

The study introduces postural sway as a new, independent fracture risk factor. The researchers point out that further research is needed in order to incorporate postural sway into a fracture risk estimation tool. This will improve current methods and help in the early identification of the elderly who are at a greater risk of having a fracture so that required interventions can be carried out in time.

A new study by a pair of researchers in the US and Japan has found that, when gravity is combined with quantum mechanics, symmetry is not possible.

"Many physicists believe that there must a beautiful set of laws in Nature and that one way to quantify the beauty is by symmetry. Some of the symmetries may be hidden in our world, but they should manifest themselves if we look at Nature at a more fundamental level. We showed that this expectation is wrong once we take into account the gravity," said Hirosi Ooguri, Director of the Kavli Institute for the Physics and Mathematics of the Universe, and one of the paper authors.

There are four kinds of fundamental forces in Nature: electromagnetism, strong force, weak force, and gravity. Of the four, the gravity is the only one still unexplainable at the quantum level. Researchers believe the holographic principle is an important hint to combine the gravity and quantum mechanics successfully.

A hologram makes three-dimensional images pop out from a two-dimensional screen. Similarly, the holographic principle allows physicists to study gravitational systems by projecting them on a boundary that surrounds the entire Universe. The AdS/CFT (anti-de Sitter/conformal field theory) correspondence, developed in the late 1990s by Juan Maldacena, has been particularly useful because it gives a precise mathematical definition of the holographic principle.

In the paper published on May 17, Ooguri and Daniel Harlow, Assistant Professor at Massachusetts Institute of Technology, proved that symmetry is not possible in a gravitational theory if it obeys the holographic principle.

Previous work by Harlow and others had found a precise mathematical analogy between the holographic principle and quantum error correcting codes, which protects information in a quantum computer. In the new paper, Ooguri and Harlow showed such quantum error correcting codes are not compatible with any symmetry, meaning that symmetry would not be possible in quantum gravity.

Their result has several important consequences. In particular, it predicts that the protons are stable against decaying into other elementary particles, and that magnetic monopoles exist.

Details of their study were published in Physical Review Letters on May 17 and selected for Editor's Suggestion "due to its particular importance, innovation, and broad appeal."

Researchers have presented a new strategy for efficiently producing fatty acids and biofuels that can transform glucose and oleaginous microorganisms into microbial diesel fuel, with one-step direct fermentative production.

The newly developed strain, created by Distinguished Professor Sang Yup Lee and his team, showed the highest efficiency in producing fatty acids and biodiesels ever reported. It will be expected to serve as a new platform to sustainably produce a wide array of fatty acid-based products from glucose and other carbon substrates.

Fossil fuels, which have long been energy resources for our daily lives, are now facing serious challenges: depletion of their reserves and their role in global warming. The production of sustainable bio-based renewable energy has emerged as an essential alternative and many studies to replace fossil fuels are underway. One of the representative examples is biodiesel. Currently, it is mainly being produced through the transesterification of vegetable oils or animal fats.

The research team engineered oleaginous microorganisms, Rhodococcus opacus, to produce fatty acids and their derivatives that can be used as biodiesel from glucose, one of the most abundant and cheap sugars derived from non-edible biomass.

Professor Lee's team has already engineered Escherichia coli to produce short-chain hydrocarbons, which can be used as gasoline (published in Nature as the cover paper in 2013). However, the production efficiency of the short-chain hydrocarbons using E. coli (0.58 g/L) fell short of the levels required for commercialization.

To overcome these issues, the team employed oil-accumulating Rhodococcus opacus as a host strain in this study. First, the team optimized the cultivation conditions of Rhodococcus opacus to maximize the accumulation of oil (triacylglycerol), which serves as a precursor for the biosynthesis of fatty acids and their derivatives. Then, they systematically analyzed the metabolism of the strain and redesigned it to enable higher levels of fatty acids and two kinds of fatty acid-derived biodiesels (fatty acid ethyl esters and long-chain hydrocarbons) to be produced.

They found that the resulting strains produced 50.2, 21.3, and 5.2 g/L of fatty acids, fatty acid ethyl esters, and long-chain hydrocarbons, respectively. These are all the highest concentrations ever reported by microbial fermentations. It is expected that these strains can contribute to the future industrialization of microbial-based biodiesel production.

"This technology creates fatty acids and biodiesel with high efficiency by utilizing lignocellulose, one of the most abundant resources on the Earth, without depending on fossil fuels and vegetable or animal oils. This will provide new opportunities for oil and petroleum industries, which have long relied on fossil fuels, to turn to sustainable and eco-friendly biotechnologies," said Professor Lee.

Plants are susceptible to stress, and with the global impact of climate change and humanity's growing demand for food, it's crucial to understand what causes plant stress and stress tolerance. When plants absorb excess light energy during photosynthesis, reactive oxygen species are produced, potentially causing oxidative stress that damages important structures. Plants can suppress the production of reactive oxygen species by oxidizing P700 (the reaction center chlorophyll in photosystem I). A new study has revealed more about this vital process: the cyclic electron flow induced by P700 oxidation is an electric charge recombination occurring in photosystem I. These findings were published on June 5 in Plants.

The research was led by Professor Chikahiro Miyake, Assistant Professor Shinya Wada, and Kanae Kadota (Kobe University), in collaboration with Professor Amane Makino (Tohoku University) and Associate Professor Yuji Suzuki (Iwate University).

Professor Miyake's team revealed in previous studies that all oxygen-producing photosynthetic species use the P700 oxidation system to deal with oxidative stress. Professor Miyake and Dr Giles Johnson (Senior Lecturer at the University of Manchester) discovered that P700 oxidation is accompanied by a cyclic electron flow (CEF) in photosystem I (PSI). This cyclic flow is not necessary for the linear electron flow that forms part of photosynthesis, so what is it doing? To find out more about this alternative flow, the team analyzed the interaction between the electron carriers linked to the reaction in the PSI complex and the PSII quantum yield [Y(II)] that evaluates the activity levels of the linear electron flow. They used a major crop: wheat leaves.

The results showed that in the electron flow from P700* (excited P700) to ferredoxin (Fd), electron carriers A0, A1, FX, FA/FB are present, and when P700?(oxidized P700) accumulates, a charge recombination occurs in which electrons flow in from the electron carriers (Figure 2). In P700* charge separation occurs, passing electrons to the electron carrier A0 and oxidizing to form P700+. P700+ receives electrons from PSII and is reduced to its ground state. Meanwhile, the electrons accepted by A0 are passed to A1, FX, and FA/FB and flow to NADP+ via Fd, ultimately producing NADPH (chemical energy used in photosynthesis). From observing the reaction speed in leaf samples, the charge recombination between FX and P700+ can be considered the dominant pathway.

The existence of the charge recombination had already been revealed on a cellular level in biochemically isolated PSI complexes, cyanobacteria and green alga. However, until now its role in photosynthesis was unclear. This finding suggests that electrons flow from FX to P700+ based on the reactivity of P700+.

As a secondary result, the team also revealed the mechanism for suppressing the production of reactive oxygen species based on the charge recombination. The electron carriers A0, A1, FX, FA/FB have a very low reduction potential compared to that of oxygen. This suggests that they can easily pass electrons to oxygen and produce reactive oxygen species. The charge recombination revealed in this study plays the role of suppressing the interaction between these electron carriers and oxygen.

This study proposes that the cyclic electron flow induced by P700 oxidation is characterized by a charge recombination reaction that occurs within the PSI complex, including the necessary conditions and the cyclic electron carrier speed. The next step is to investigate the universality of the role of charge recombination within PSI complexes.

Is glue the answer to climate change? Researchers at the Energy Safety Research Institute (ESRI) at Swansea University have proven that it could certainly help.

They have developed a new material capable of capturing the greenhouse gas carbon dioxide (CO2) with the key ingredient being a common epoxy resin you probably have at home.

Carbon capture materials are a crucial part of a range of technologies, alongside renewables and energy efficiency solutions, that can help reduce the amount of CO2 we release into the atmosphere.

"We show that small epoxy molecules typically found in glues can stick larger ones together to make effective carbon capture materials potentially useful to tackle climate change," said Dr Enrico Andreoli, lead of the research study now subject of a paper published in Chemistry of Materials.

Dr Louise Hamdy, first author of the paper, added "We've developed a new approach to making an effective CO2 capture material from a widely studied CO2-reactive polyamine by reaction with an industrially mass-produced epoxy resin. This material shows very high CO2 uptake and could potentially be used to capture CO2 from industrial flue gas streams or from the air, relieving us from some of the worst effects of global warming."

Current CO2 capture technologies need to be significantly advanced. Major challenges include materials cost, capacity, CO2-selectivity, regeneration, robustness and stability to water. Solid CO2 capture materials composed of polyamines supported on alumina or silica have emerged as promising carbon capture materials.

However, rather than follow suit, the researchers at ESRI cross-linked the polyamine into a solid by using epoxy resin - constituting just one-tenth of the mass of the material - maximising the CO2-reactive component and avoiding the use of a support. "This confirms the validity of my original idea of using cross-linking as an alternative to bulky supports," said Andreoli.

The cross-linked material modified with a hydrophobic additive captured almost 20% of its weight in pure CO2 at 90 °C. This finding confirmed a previous hypothesis that the introduction hydrophobic groups can disrupt the internal structure of the material to promote CO2 uptake by the polyamine.

The additive not only increased the amount of captured CO2 but did so at a lower temperature. Hamdy commented, "This finding is significant as it proves that through the introduction of additives, we can fine tune these materials for optimum performance at specific working temperatures."

Experiments revealed the functionalised sample to be highly selective for CO2 over nitrogen (N2), showing negligible uptake of N2. Selectivity was further explored by testing the material performance under flue gas-like conditions. This revealed that the sample could capture 9.5% of its weight in CO2 under a dilute CO2 stream of 10% CO2/90% N2 at 90 °C in only 15 minutes.

On subjecting the material to repetitive capture cycles, increasing the temperature to 155 °C under pure CO2 for 5 minutes to regenerate, the material showed no loss of capacity for 29 cycles, testament to the robustness of the material.

The functionalised material also performed exceptionally well under humid conditions - often a huge challenge for many CO2 sorbent solids. At 25 °C, in pure CO2, the pre-hydrated material was able to capture an impressive 23.5%. This opens up the possibility of this material being developed for capture of CO2 directly from the air.

"This research is defining a new and promising direction to economical and effective carbon capture materials. Our institute has a strong focus on developing and deploying new technologies in the field of carbon capture, utilisation, and storage. This paper is evidence of the level of our expertise," said Professor Andrew Barron, founder and director of ESRI.

COLUMBIA, Mo. (June 19, 2019) Colon cancer is the second leading cause of cancer death in the United States and colonoscopy is the most-used screening tool to detect it. In a recently published study, researchers from the University of Missouri School of Medicine determined deep sedation does not improve the colonoscopy quality compared to moderate sedation when it comes to the polyp detection rate or adenoma detection rate, the type of polyp that can eventually become cancerous.

"University of Missouri Health Care is always examining ways to improve colonoscopy quality for patients," said Matthew Bechtold, MD, professor of clinical medicine at the University of Missouri School of Medicine. "The most important quality measure is the adenoma detection rate and polyp detection rate."

Researchers conducted a retrospective study of 585 healthy average-risk patients who underwent either a moderate or deep sedation colonoscopy at the same MU Health Care outpatient center in 2015 or 2016. They found the adenoma and polyp detection rates were not significantly different between the deep sedation and mild sedation groups. Previous studies have indicated a majority of colonoscopies in the U.S. use moderate sedation instead of deep sedation.

"You usually have 30 minutes to do a colonoscopy," said Bechtold. "When you sedate with moderate sedation techniques, it takes up to twenty minutes to sedate the patient. Deep sedation with Propofol takes about 15 seconds. Is the time better spent looking at a patient's colon or waiting for them to become sedated? That's why we thought maybe the deep sedation would yield a better detection rate."

Deep sedation requires the presence of an anesthesiologist or a certified registered nurse anesthetist, which increases the cost of the procedure. Bechtold believes that if payment models change, outpatient centers may re-consider moderate sedation if it won't affect the adenoma detection rate. But the fast-acting nature of deep sedation combined with the improved patient experience is the reason why it is the preferred choice at MU Health Care.

"If we found a significant improvement in detection with moderate sedation compared to deep sedation, then we may consider going back to moderate sedation," Bechtold said. "But since we didn't really find a difference, I think the efficiency factor of deep sedation wins out."

Many of North America's migratory songbirds, which undertake awe-inspiring journeys twice a year, are declining at alarming rates. For conservation efforts to succeed, wildlife managers need to know where they go and what challenges they face during their annual migration to Latin America and back. For a new study published by The Condor: Ornithological Applications, researchers in six states assembled an unprecedented effort to track where Prothonotary Warblers that breed across the eastern U.S. go in winter--their "migratory connectivity"--and found that nearly the entire species depends on a relatively small area in Colombia threatened by deforestation and sociopolitical changes.

The Ohio State University's Christopher Tonra and his colleagues coordinated the deployment of 149 geolocators, tiny devices that use the timing of dawn and dusk to estimate birds' locations, on Prothonotary Warblers captured at sites across their breeding range. When the birds returned to their nesting sites the following year, the researchers were able to recover 34 devices that contained enough data for them to use. The geolocator data showed that regardless of where they bred, most of the warblers used the same two major Central American stopover sites during their migration and spent the winter in a relatively small area of northern Colombia. Additionally, many Prothonotary Warblers appeared to winter in inland areas, rather than in coastal mangrove habitat, which previous studies suggested they relied on most heavily.

These unexpected findings show that we may not understand the winter habitat needs of migratory songbirds as well as we thought. "The most surprising thing about the results was the overwhelming importance of Colombia to this species," says Tonra. "We weren't sure what to expect in terms of migratory connectivity, but we never expected that nearly every bird would use the same wintering region. This provided a clear conservation message and shows the power of geolocators in addressing gaps in our knowledge of migratory songbirds." Colombia's 50-year civil war accelerated deforestation in the region of the country where the warblers are concentrated, but the good news is that the convergence of birds in this single area means that conservation efforts targeted here could benefit breeding populations across North America.

Collecting data on birds across such a broad geographic area required close collaboration among the study's thirteen coauthors. "This was very much a team effort, but it really started with Erik Johnson at Audubon Louisiana and Jared Wolfe with the Louisiana Bird Observatory," says Tonra. "Erik founded and leads our Prothonotary Warbler Working Group, and he initiated the idea of deploying tags across their range. This was an extremely rewarding example of what you can accomplish through collaboration across the range of a species of concern. Everyone put in an enormous effort to gather data in their region, as well as contributing to the preparation of the paper."

A new Gender, Work & Organization analysis of U.S. data from 1997-2016 provides new insights into workplace sexual harassment.

The analysis found that declines in workplace sexual harassment complaints have been uneven, with African-American women experiencing an increased risk of sexual harassment, even as overall reported harassment complaints are down. In addition, higher unemployment rates were linked to increases in sexual harassment of women in American workplaces. Specifically, a higher unemployment rate in a particular month was followed by an increase in the number of reported harassment cases in the following month.

The authors noted that sexual harassment in the workplace appears to be an expression of power, or a way for men to assert their dominance. The shift from sexual harassment of white women to sexual harassment of African-American women indicates that harassers are conscious of power relationships and choose to target more vulnerable women in their workplaces. The link between changes in the unemployment rate and changes in sexual harassment indicates that men are more likely to engage in harassment behavior when they feel that their economic position in society is likely to be under threat.

"Over the past 20 years, we've made great strides in reducing sexual harassment in the workplace, but those benefits have all gone to white women, and mostly to young white women," said co-author Dan Cassino, MA, PhD, of Fairleigh Dickinson University, in New Jersey. "It seems as though men have gotten more careful about who they're harassing and have been targeting women of color, who may be less likely to report the harassment."

Eating two or more weekly servings of yogurt may help to lower the risk of developing the abnormal growths (adenomas) which precede the development of bowel cancer--at least in men--finds research published online in the journal Gut.

The observed associations were strongest for adenomas that are highly likely to become cancerous, and for those located in the colon rather than in the rectum, the findings indicate.

Previously published research has suggested that eating a lot of yogurt might lower the risk of bowel cancer by changing the type and volume of bacteria in the gut (microbiome).

But it's not been clear whether yogurt intake might also be associated with a lower risk of pre-cancerous growths, known as adenomas.

The researchers therefore looked at the diets and subsequent development of different types of adenoma among 32,606 men who were part of the Health Professionals Follow Up Study and 55,743 women who were part of the Nurses Health Study.

All the study participants had had a lower bowel endoscopy--a procedure that enables a clinician to view the inside of the gut--between 1986 and 2012. And every four years, they provided detailed information on lifestyle and diet, including how much yogurt they ate.

During the study period, 5811 adenomas developed in the men and 8116 in the women.

Compared with men who didn't eat yogurt, those who ate two or more servings a week were 19% less likely to develop a conventional adenoma.

This lower risk was even greater (26%) for adenomas that were highly likely to become cancerous, and for those located in the colon rather than in the rectum.

While no obvious association was seen for men with a potentially more dangerous type of adenoma (serrated), a trend towards reduced risk was seen for those measuring 1 or more cm, which is considered to be large.

No such associations between yogurt intake and the development of adenomas were evident among the women.

This is an observational study, and as such, can't establish cause. Further research would be needed to confirm the findings and uncover the biology involved, emphasise the researchers.

But the large number of people studied and the regular updates on diet and lifestyle factors add heft to the findings, they suggest.

By way of a possible explanation for what they found, the researchers point out that Lactobacillus bulgaricus and Streptococcus thermophilus, two bacteria commonly found in live yogurt, may lower the number of cancer causing chemicals in the gut.

And the stronger link seen for adenomas growing in the colon may partly be due to the lower acidity (pH) in this part of the gut, making it a more hospitable environment for these bacteria, they add.

Alternatively, yogurt may have anti-inflammatory properties and may reduce the 'leakiness' of the gut as adenomas are associated with increased gut permeability, they suggest.

Researchers at the JCU Turtle Health Research Facility have conducted a first-of-its-kind study using what's known as phage therapy as an option for bacterial infections in green sea turtles.

Phage therapy uses so-called 'good viruses' (bacteriophages) that occur naturally in the environment and kill bacteria.

"Green turtles rely on 'good bacteria' in their gut to extract nutrients from food," said Dr Robert Kinobe, one of the researchers involved in the study.

"This creates a challenge when it comes to treating bacterial infections because if we administer antibiotics, it can destroy the 'good bacteria' and make the turtle's health worse."

Researchers at the JCU Turtle Health Research Facility applied 'good viruses' to green sea turtles and found that it was successful in eliminating the targeted 'bad bacteria' without hampering the non-targeted 'good bacteria'.

"This shows that phage therapy can be safe and effective enough to manipulate or treat targeted bacteria in green sea turtles," said Dr Kinobe.

A further complication, previously identified by the JCU Turtle Health Research Facility, is the existence of antibiotic-resistant bacteria in the guts of green sea turtles, which are found in several locations along the Queensland coast.

"Antimicrobial resistance is one of the most critical issues we face, which is why this finding of an alternative to antibiotics is so important," said co-author Dr Lisa Elliott.

"Bacteriophages and phage therapy have already been suggested as an alternative for antibiotics in humans, but we also need to investigate its scope for treatment in animals."

The research has been published in the Journal of Environmental Microbiology and opens the door for future applications of phage therapy as an alternative to antibiotics in treating bacterial infections in turtles and other marine animals.

WASHINGTON, D.C., June 18, 2019 -- It sounds like an old-school vinyl record, but the distinctive crackle in the music streamed into Chris Holloway's laboratory is atomic in origin. The group at the National Institute for Standards and Technology, Boulder, Colorado, spent a long six years finding a way to directly measure electric fields using atoms, so who can blame them for then having a little fun with their new technology?

"My vision is to cut a CD in the lab -- our studio -- at some point and have the first CD recorded with Rydberg atoms," said Holloway. While he doesn't expect the atomic-recording's lower sound quality to replace digital music recordings, the team of research scientists is considering how this "entertaining" example of atomic sensing could be applied in communication devices of the future.

"Atom-based antennas might give us a better way of picking up audio data in the presence of noise, potentially even the very weak signals transmitted in deep space communications," said Holloway, who describes his atomic receiver in AIP Advances, from AIP Publishing.

The atoms in question -- Rydberg atoms -- are atoms excited by lasers into a high energy state that responds in a measurable way to radio waves (an electric field). After figuring out how to measure electric field strength using the Rydberg atoms, Holloway said it was a relatively simple step to apply the same atoms to record and play back music -- starting with Holloway's own guitar improvisations in A minor.

They encoded the music onto radio waves in much the same way cellphone conversations are encoded onto radio waves for transmission. The atoms respond to these radio waves, and in turn, the laser beams shined through the Rydberg atoms are affected. These changes are picked up on a photodetector, which feeds an electric signal into the speaker or computer -- and voila! The atomic radio was born.

The team used their quantum system to pick up stereo -- with one atomic species recording the instrumental and another the vocal at two different sets of laser frequencies. They selected a Queen track -- "Under Pressure" -- to test if their system could handle Freddie Mercury's extensive vocal range.

"One of the reasons for cutting stereo was to show that this one receiver can pick up two channels simultaneously, which is difficult with conventional receivers," said Holloway, who explained that although it is the early days for atomic communications, there is potential to use this to improve the security of communications.

For now, Holloway's team are staying tuned into atomic radio as they try to determine how weak a signal the Rydberg atoms can detect, and what data transfer speeds can be achieved.

They are not forgetting the atomic record they want to produce, with which they hope to inspire the next generation of quantum scientists.

After fasting for 24 hours the typical laboratory mouse spends much time eating. Surprisingly, this is not what Jay M. Patel saw when he was studying basal forebrain circuits in mice.

"When I joined Dr. Benjamin Arenkiel's lab, they had just discovered a unique set of circuits in the basal forebrain, a region separate from the hypothalamus, the brain area that normally regulates how much you eat depending on how much energy you spend," said Patel, a student in the neuroscience Medical Scientist Training Program (M.D./Ph.D.) at Baylor College of Medicine. "I wanted to investigate what these circuits that are linked to the feeding center of the brain were actually doing."

Using cutting-edge technologies, including microendoscopy-imaging protocols, Patel and his colleagues first investigated what types of stimuli would activate the circuits. By recording the activity of the neurons, Patel found that food odors highly activated a subset of neurons in the basal forebrain identified by the expression of the molecule vGlut2.

"That was very interesting because we know that the sense of smell can drive appetite. For instance, after smelling dessert, you may want to eat it even though you just had a big meal. Or conversely, after smelling a spoiled dish you won't eat it, even if you are very hungry," Patel said.

Although researchers knew that the perception of food odors itself can affect neuronal activity in the hypothalamus, it was unclear how odor perception was relayed to the hypothalamus. They were excited at the possibility that the novel vGlut2+ basal forebrain circuits might provide an answer.

Surprising results
Patel and his colleagues studied the effect of specifically activating vGlut2+ neurons in the basal forebrain and observed dramatically altered feeding behavior in mice.

"Surprisingly, four to five days after we began the experiment, the mice started to lose weight quickly," Patel said.

The researchers determined that the animals' rapid weight loss could not be explained by metabolic dysfunction, as they found no differences between the levels of pituitary or thyroid hormones, or in the levels of glucose, insulin or leptin between the experimental and control groups. The mice lost weight rapidly because they had stopped eating.

"They did not eat even when they were hungry, which we found remarkable because animals are compelled to eat to survive," Patel said.
Interestingly, further experiments showed that naturally aversive odors had a stronger effect on vGlut2+ basal forebrain neurons than food alone, triggering a food avoidance behavior in mice.

"It seemed that the animals were afraid of food," Patel said. "Even though they were hungry, they avoided locations where food was placed."

"We have identified a brain circuit driven by vGlut2+ neurons in the basal forebrain that suppresses appetite when it's active and stimulates feeding behavior when it's inactive," Patel said. "We also determined that this circuit, which is formed by just a couple of thousand neurons involved in perceiving the outside world, connects with and overrides feeding behaviors regulated by the hypothalamus."

"We think this work has potential implications that reach beyond feeding behaviors and mouse physiology," said Arenkiel, associate professor of neuroscience and molecular and human genetics and a McNair Scholar at Baylor. He is also a member of the Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital. "This circuit is highly involved with how our brain perceives the outside world and brings this information to the hypothalamus, thus connecting with aspects of physiology like feeding, which relates to eating disorders that are associated with many neuropsychiatric conditions."