Tech

Why did you choose your job? Or where you live? Scientists at the University of Warwick have discovered that it was probably to keep your options as open as possible - and the more we co-operate together, the more opportunities are available to us.

Using flocks of birds as a model, they have shown that birds of a feather will indeed flock together to maximise the information they have access to and to give them the most future options when flocking.

The discovery by Henry Charlesworth and his supervisor Professor Matthew Turner published on 15 July in Proceedings of the National Academy of Sciences and provides a clue to the emergence of social co-operation in animals by explaining how individuals gain greater advantages by working in groups. The research was partially funded by the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation.

The researchers sought to gain a better understanding of collective motion, like that seen in a flock of birds, a herd of animals, an insect swarm or a human crowd.

They created a computer simulation, using bird flocks as a model, in which the 'birds' perceived a visual representation of the world around them, as if through a simple retina. They then programmed them with an algorithm based on the principle of Future State Maximisation (FSM), so the 'birds' would move to maximise the number of different visual environments that they expect to be able to access in the future.

The way they move together resembled animals in several ways, including cohesion (they stick together), co-alignment (they fly in roughly the same direction as their neighbours) and collision suppression, none of which were specifically programmed into the model. This demonstrates that there is a fundamental advantage to the 'birds' in working together.

Professor Matthew Turner, from the University of Warwick Department of Physics, said: "We adopted a hypothesis that birds are agents that want to maximise their future freedom, and then we asked what the consequences are of that. It looks like it generates dynamics that are extremely similar, even at the quantitative level, to a bird flock. That begs the question of whether this principle is actually the fundamental organisational principle in birds, and possibly in all intelligent life?

"We start from this low-level principle and are able to predict that these agents will move together, what density they will target, what kind of level of order they'll target. All of these things look remarkably similar to what you get in animal systems."

The algorithm is similar to 'tree searches' that have been used for a number of years in applications like chess programs. Chess algorithms would build tree searches of future lines of play and then select those lines that give them the maximum future options, among other factors.

The discovery has applications in a host of fields such as in robotics, drone swarms, farming and even CGI graphics, where creating realistic swarms is seen as a gold standard.

This latest research also suggests that this principle may be a fundamental tool for information processing agents and perhaps help to define intelligence itself.

Professor Turner adds: "People should ask themselves how they make decisions in their own lives - do they make decisions instinctively or are they trying to optimise something?

"This is a deep question in science, the emergence of social co-operation. We would argue that having a social organisation like a bird flock, because you're all together and social, you collectively gain much more freedom than you would if you were an individual. If you are an individual you would live in a very boring world, you wouldn't be able to interact with your neighbours, or in the context of our society, to request tasks or provide services.

"The idea is that this principle of keeping your options open might be connected to intelligence, and as quantitative scientists we can build a model that shows us what the consequences of that are."

The experts assume that one reason for this preference is that emotions are primarily processed in the right hemisphere of the brain, which is linked to the left side of the body. The team led by lead author Julian Packheiser reports in the journal Neuroscience and Biobehavioral Reviews on 26 June 2019.

First study from 1960

International researchers have been investigating since 1960 whether and why people have a preferred side when cradling a baby. Some studies have demonstrated a preference, others have not. "In order to explain the effect, we looked for all of the studies we could find on this topic," says Julian Packheiser. The Bochum-based researchers included 40 studies in their analysis.

They ultimately found that between 66 and 72 per cent of all people hold an infant with their left arm. For right-handed people, the figure is even higher at 74 per cent, while it is only 61 per cent for left-handed people. The ratio is similar for men and women: 64 per cent of all men and 73 per cent of all women hold a baby with their left arm. "There may, of course, be links between gender and handedness," explains Packheiser. After all, men are 23 per cent more likely to be left-handed than women. "Unfortunately, this link has not been considered in any study," says the researcher.

Emotions can be crucial

There has been much speculation about the reasons for the side preference. Perhaps right-handed people are only holding the baby on the left so that they have their right, more dexterous hand free. However, since emotions are primarily processed in the right hemisphere of the brain, people may also tend to move their baby into their left visual field, which is linked to the right hemisphere of the brain. This could be especially true for mothers who have already established a strong emotional bond with their child during pregnancy.

As regards men, the researchers from Bochum are comparing the results of the analysis with their own study on hugs. During this study, they discovered that men who are uncomfortable hugging other men tend to hug each other from the left because of the strong negative emotions. "Further studies would have to take into account the emotional context of holding babies," says Julian Packheiser.

Scientists at Linkoping University working with colleagues from China have shown how to achieve efficient perovskite light-emitting diodes (LEDs). In an article published in Nature Communications, they provide guidelines on fabricating high-quality perovskite light emitters, and consequently high-efficiency perovskite LEDs.

The halide perovskites, which are defined by their crystal structures, can be easily prepared by low-cost solution processing from precursor solution comprising metal halides and organic halides. The resulting perovskites possess excellent optical and electrical properties, making them promising candidates for various kinds of optoelectronic devices, such as solar cells, LEDs and photodetectors.

Since solution-processed perovskites contain large amounts of defects, which are mostly halide vacancies, efficient control of the perovskite crystallinity is required for high-performance optoelectronic devices. The research group at LiU, under the leadership of Senior Lecturer Feng Gao, in collaboration with scientists from Nanjing Tech University, and Soochow University in China, has now studied how the precursor components and the interfaces affect the crystallisation process of perovskites.

"We and several other groups found that simply introducing an extra amount of organic halides in the precursor can help to passivate the defects and achieve highly emissive perovskite films" says Zhongcheng Yuan, PhD student in Department of Physics, Chemistry and Biology (IFM) at LiU, who is the first author of the article. The excess organic halides, however, hamper the perovskite crystallisation, resulting in low-conductivity perovskite emissive layers and poor-performance LEDs.

The scientists have now resolved this dilemma by supporting the perovskite crystallisation with a metal oxide, ZnO, which helps to remove a suitable number of the extra organic cations, making it possible for better crystallization. The article in Nature Communications shows how chemical reactions between different metal oxide layers and perovskite layers affect the properties of the thin films of perovskites, and consequently the performance of LEDs.

"We achieve the precise control by taking advantage of the basic nature of zinc oxide, which can selectively remove the undesired organic cations while leaving the desired halide anions", says Sai Bai, research fellow at the Department of Physics, Chemistry and Biology (IFM) at LiU. He and Feng Gao are the principal authors of the article.

This new discovery, in combination with previous results from the same group on dealing with defects in perovskites, has allowed them to fabricate efficient perovskite light-emissive films in the laboratory. The resulting devices give near-infrared LEDs with a quantum efficiency of 19.6%, i.e. 19.6% of the electrons supplied to the device are emitted as light (photons), which is among the best performance for perovskite LEDs in the world.

"Perovskite LEDs are a promising field. Rapid breakthroughs have been witnessed during the past 5 years, but this field is still new and much more work needs to be done before they can be commercially manufactured at a large scale. One critical aspect that needs to be improved is the device stability", says Feng Gao.

LAWRENCE -- Imagine printing electronic devices using a simple inkjet printer -- or even painting a solar panel onto the wall of a building.

Such technology would slash the cost of manufacturing electronic devices and enable new ways to integrate them into our everyday lives. Over the last two decades, a type of material called organic semiconductors, made out of molecules or polymers, has been developed for such purposes. But some properties of these materials pose a major hurdle that limits their widespread use.

"In these materials, an electron is usually bound to its counterpart, a missing electron known as 'hole,' and can't move freely," said Wai-Lun Chan, associate professor of physics & astronomy at the University of Kansas. "So-called 'free electrons,' which wander freely in the material and conduct electricity, are rare and can't be generated readily by light absorption. This impedes the use of these organic materials in applications like solar panels because panels built with these materials often have poor performance."

Because of this problem, Chan said "freeing the electrons" has been a focus in developing organic semiconductors for solar cells, light sensors and many other optoelectronic applications.

Now, two physics research groups at KU, led by Chan and Hui Zhao, professor of physics & astronomy, have effectively generated free electrons from organic semiconductors when combined with a single atomic layer of molybdenum disulfide (MoS2), a recently discovered two-dimensional (2D) semiconductor.

The introduced 2D layer allows the electrons to escape from "holes" and move freely. The findings have just been published in the Journal of American Chemical Society, a leading journal in chemistry and interfacing areas of science.

Over the last few years, many researchers have been investigating how free charges can be generated effectively from hybrid organic-2D interfaces.

"One of the prevailing assumptions is free electrons can be generated from the interface as long as electrons can be transferred from one material to another in a relatively short period of time -- less than one-trillionth of a second," Chan said. "However, my graduate students Tika Kafle and Bhupal Kattel and I have found the presence of the ultrafast electron transfer in itself is not sufficient to guarantee the generation of free electrons from the light absorption. That's because the 'holes' can prevent the electrons from moving away from the interface. Whether the electron can be free from this binding force depends on the local energy landscape near the interface."

Chan said the energy landscape of the electrons could be seen as a topographic map of a mountain.

"A hiker chooses his path based on the height contour map," he said. "Similarly, the motion of the electron at the interface between the two materials is controlled by the electron energy landscape near the interface."

Chan and Zhao's findings will help develop general principles of how to design the "landscape" to free the electrons in such hybrid materials.

The discovery was made by combining two highly complementary experimental tools based on ultrafast lasers, time-resolved photoemission spectroscopy in Chan's lab and transient optical absorption in Zhao's lab. Both experimental setups are located in the basement of the Integrated Science Building.

In the time-resolved photoemission spectroscopy experiment, Kafle used an ultrashort laser pulse that only exists for 10-quadrillionths (10-14) of a second to trigger the motion of electrons. The advantage of using such a short pulse is the researcher knows precisely the starting time of the electron's journey. Kafle then used another ultrashort laser pulse to hit the sample again at an accurately controlled time relative to the first pulse. This second pulse is energetic enough to kick out these electrons from the sample. By measuring the energy of these electrons (now in a vacuum) and using the principle of energy conservation, the researchers were able to figure out the energy of electrons before they were kicked out and thus reveal the journey of these electrons since they were hit by the first pulse. This technique resolved the energy of the excited electrons as it moves across the interface after the light absorption. Because only electrons near the front surface of the sample can be released by the second pulse, the position of the electron relative to the interface is also revealed with atomic precision.

In the transient optical absorption measurements, Peng Yao (a visiting student) and KU graduate Peymon Zereshki, both supervised by Zhao, also used a two-pulse technique, with the first pulse initiating the electron motion in the same way. However, in their measurements, the second pulse does the trick of monitoring electrons by detecting the fraction of the second pulse that is reflected from the sample, instead of kicking out the electrons.

"Because light can penetrate a longer distance, the measurement can probe electrons in the entire depth of the sample and therefore provide complementary information to the first techniques that are more 'surface sensitive,'" Zhao said. "These detailed measurements enabled us to reconstruct the trajectory of the electron and determine conditions that enable the effective generation of free electrons."

Over the past decade, a major trend in electronics has been the development of sensors, displays and smart devices which are seamlessly integrated onto the human body. Most of these wearable devices are singularly connected to a user's smart phone and transmit all data via Bluetooth or Wi-Fi signals. But as consumers wear increasing numbers of wearable devices, and as the data they transmit increases in sophistication, more innovative connection methods are being sought after.

Now, researchers from the National University of Singapore (NUS) have invented a completely new way for wearable devices to interconnect. They incorporated conductive textiles into clothing to dynamically connect several wearable devices at once. This 'wireless body sensor network' allows devices to transmit data with 1,000 times stronger signal than conventional technologies, meaning the battery life of all devices is dramatically improved. Wireless networks of these wearable devices on a body have future applications in health monitoring, medical interventions and human-machine interfaces.

This technological breakthrough, which took the 10-member team a year to achieve, was published as the cover of Nature Electronics on 17 June 2019.

Better data transmission, greater privacy

Currently, almost all body sensors like smart watches connect to smartphones and other wearable electronics via radio-waves like Bluetooth and Wi-Fi. These waves radiate outwards in all directions, meaning that most of the energy is lost to the surrounding area. This method of connectivity drastically reduces the efficiency of the wearable technology as most of its battery life is consumed in attempting the connection.

As such, Assistant Professor John Ho and his team from the Institute for Health Innovation & Technology (NUS iHealthtech) and the NUS Faculty of Engineering wanted to confine the signals between the sensors closer to the body to improve efficiency.

Their solution was to enhance regular clothing with conductive textiles known as metamaterials. Rather than sending waves into surrounding space, these metamaterials are able to create 'surface waves' which can glide wirelessly around the body on the clothes. This means that the energy of the signal between devices is held close to the body rather than spread in all directions. Hence, the wearable electronics use much less power than normal, and the devices can detect much weaker signals.

"This innovation allows for the perfect transmission of data between devices at power levels that are 1,000 times reduced. Or, alternatively, these metamaterial textiles could boost the received signal by 1,000 times which could give you dramatically higher data rates for the same power," Asst Prof Ho stated. In fact, the signal between devices is so strong that it is possible to wirelessly transmit power from a smartphone to the device itself -- opening the door for battery-free wearable devices.

Crucially, this signal boost does not require any changes to either the smartphone or the Bluetooth device -- the metamaterial works with any existing wireless device in the designed frequency band.

This inventive way of networking devices also provides more privacy than conventional methods. Currently, radio-waves transmit signals several metres outwards from the person wearing the device, meaning that personal and sensitive information could be vulnerable to potential eavesdroppers. By confining the wireless communication signal to within 10 centimetres of the body, Asst Prof Ho and his team have created a network which is more secure.

Intelligent design, enhanced capabilities

The team has a first-year provisional patent on the metamaterial textile design, which consists of a comb-shaped strip of metamaterial on top of the clothing with an unpatterned conductor layer underneath. These strips can then be arranged on clothing in any pattern necessary to connect all areas of the body. The metamaterial itself is cost-effective, in the range of a few dollars per metre, and can be bought readily in rolls.

"We started with a specific metamaterial that was both flat and could support surface waves. We had to redesign the structure so that it could work at the frequencies used for Bluetooth and Wi-Fi, perform well even when close to the human body, and could be mass produced by cutting sheets of conductive textile," Asst Prof Ho explained.

The team's particular design was created with the aid of a computer model to ensure successful communication in the radio frequency range and to optimise overall efficacy. The smart clothing is then fabricated by laser-cutting the conductive metamaterial and attaching the strips with fabric adhesive.

Once made, the 'smart' clothes are highly robust. They can be folded and bent with minimal loss to the signal strength, and the conductive strips can even be cut or torn, without inhibiting the wireless capabilities. The garments can also be washed, dried, and ironed just like normal clothing.

Next steps

The team is talking to potential partners to commercialise this technology, and in the near future Asst Prof Ho is hoping to test the 'smart' textiles as specialised athletic clothing and for hospital patients to monitor performances and health. Potential applications could range dramatically -- from measuring a patient's vital signs without inhibiting their freedom of motion, to adjusting the volume in an athlete's wireless headphones with a single hand motion.

[Background]

Industrial robots are now widely used and are indispensable in car manufacturing and in other fields. Conventional robot hands are suitable for grasping hard objects of fixed form, whereas it is not easy to grasp complicated objects or to gently grasp soft objects. It is also necessary, under various conditions, to respond to physical characteristics of objects such as surface characteristics: dry, wet, etc.

A soft-surfaced fingertip of a robot hand is deformable and can grasp an object of complicated form rather easily, since the contact area can be enlarged by surface deformation in response to the object form. Soft-surfaced fingertips are very effective in grasping soft objects; even tofu can be grasped. Generally, however, the surface friction of soft material is high, which makes releasing more difficult. It is also difficult to release objects to desired positions, especially in cases where the working space is narrow.

[Results]

A group led by Prof. Tetsuyou Watanabe at Kanazawa University has been conducting research on control technology for grasping objects by the fingertips of robot hands. In the present study, the group aimed to develop a friction control system. The group used the soft fingertips of a robot hand for grasping objects; releasing was accomplished by applying (injecting) a lubricant. In this study, absolute ethanol (>99.5%) was employed as lubricant, since ethanol is chemically safe and easy to dry and since its surface tension is low.

As seen in Figure 1, a nitrile rubber film was bonded to the sides of the fingertip foundation to create a space for filling with chain saw oil to make a "fluid fingertip." Then a silicone "texture"*1) was bonded to coat the rubber film; the material of the "texture" was a silicone sealant with slits, whose interval was 1.5 mm, perpendicular to the load direction. The slits were introduced for a large friction under a water-wet condition and for lubricant spreading. With this fluid fingertip, objects of various materials used for kitchen utensils were grasped and it was verified that, upon applying the lubricant, the friction was indeed reduced (Figure 2). The friction was reduced under both dry and wet conditions, whereas such a lubricating effect was not observed under an oily condition.

Next, a box packing task simulation was performed as shown in Figure 3. A paper box was grasped with two fluid fingertips from both sides. The "texture" described above was bonded to each fluid fingertip. Stable grasping was confirmed by putting a weight on the paper box. After removal of the weight, lubricant was injected to both fluid fingertips, which caused a downward slipping of the paper box in a rather short time (less than 2.5 s), so that the paper box packaging task was completed (Figure 3). As shown here, a "texture" of high friction was bonded to the fluid fingertip, and injecting a lubricant (here, absolute ethanol) reduced the friction. Thus, releasing and placing of an object at a desired position was accomplished by controlling the friction without moving the fingertips.

[Future prospects]

In this study, it was verified that object grasping by soft surface fluid fingertips with high friction was controllable by applying a suitable lubricant. It is, however, necessary to do more experiments under various conditions in order to apply the current controlling technology to manufacturing environments. Nonetheless, this study is expected to be a step forward for realizing work automation of, for example, grasping and releasing of objects in a narrow space.

[Glossary]

*1) Texture

Texture generally means the touch of woven materials, rocks, foodstuff and others. Here, texture signifies a planar substance, bonded on a foundation, contacting a target material.

*2) Equivalent maximum-static frictional coefficient (EMSFC)

Equivalent maximum-static frictional coefficient is the ratio of shearing force taking place between two objects in contact to the action force perpendicular to the contact surface under the static friction condition, i.e. where the two objects do not move relative to each other. It should be noted that the shearing force includes not only frictional force but also the force caused by the deformation on a deformable contact surface.

WEST LAFAYETTE, Ind. - Finding inexpensive solutions for propelling CubeSats is one of the most critical components of the rapidly growing industry of commercial launches of satellites the size of a loaf of bread. The small size and relatively low cost have made CubeSats popular choices for commercial launches in recent years.

The first CubeSat was launched in 1999. Since then, more than 1,000 have been launched. The rapid development and application of nanosatellite technology has vastly accelerated mission complexity - sparking interest in robust, low-power and high-specific impulse micropropulsion systems.

Purdue University researchers have created a novel micropropulsion system for nanosatellite applications using a liquid fed pulsed-plasma thruster. It uses a liquid propellant for Lorentz-force pulsed-plasma accelerator and extended lifetime ignition system driven by nanosecond long pulses.

"Our innovation helps address current challenges with CubeSat micropropulsion systems, including short operational lifetimes, contamination risks and economic challenges," said Alexey Shashurin, an assistant professor of aeronautics and astronautics in Purdue's College of Engineering. "Our system is better able to operate reliably for the entire mission and the liquid propellant we use does not create the contamination risks to the subsystems that we see with current options."

The Purdue team's work was presented in June at the 2019 IEEE Pulsed Power and Plasma Science Conference in Orlando, Florida.

Overall popularity of the CubeSats is driven heavily by the great advancement in miniaturization of electronic components and sensors that allows for new kinds of space missions and measurements using a CubeSat.

"We have taken the next step toward developing a robust propulsion system for CubeSats to provide for necessary maneuvering during missions," Shashurin said. "Developing innovative technologies like this is one of my passions."

One of the student researchers who worked on the technology, Adam Patel, was named one of "Tomorrow's Engineering Leaders" by Aviation Week Network and the American Institute of Aeronautics and Astronautics. Patel is a senior in the School of Aeronautics and Astronautics.

Shashurin and his team worked with the Purdue Research Foundation Office of Technology Commercialization to file a provisional patent on the technology. They are looking for partners to continue development.

Their work aligns with Purdue's Giant Leaps celebration of the university's global advancements in space exploration as part of Purdue's 150th anniversary. It is one of the four themes of the yearlong celebration's Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.

They outlived mammoths and saber-toothed tigers. But without dramatic action to reduce climate change, new research shows Joshua trees won't survive much past this century.

UC Riverside scientists wanted to verify earlier studies predicting global warming's deadly effect on the namesake trees that millions flock to see every year in Joshua Tree National Park. They also wanted to learn whether the trees are already in trouble.

Using multiple methods, the study arrived at several possible outcomes. In the best-case scenario, major efforts to reduce heat-trapping gasses in the atmosphere would save 19 percent of the tree habitat after the year 2070. In the worst case, with no reduction in carbon emissions, the park would retain a mere 0.02 percent of its Joshua tree habitat.

The team's findings were published recently in Ecosphere. Project lead Lynn Sweet, a UCR plant ecologist, said she hopes the study inspires people to take protective environmental action. "The fate of these unusual, amazing trees is in all of our hands," she said. "Their numbers will decline, but how much depends on us."

To answer their questions about whether climate change is already having an effect, a large group of volunteers helped the team gather data about more than 4,000 trees.

They found that Joshua trees have been migrating to higher elevation parts of the park with cooler weather and more moisture in the ground. In hotter, drier areas, the adult trees aren't producing as many younger plants, and the ones they do produce aren't surviving.

Joshua trees as a species have existed since the Pleistocene era, about 2.5 million years ago, and individual trees can live up to 300 years. One of the ways adult trees survive so long is by storing large reserves of water to weather droughts.

Younger trees and seedlings aren't capable of holding reserves in this way though, and the most recent, 376-week-long drought in California left the ground in some places without enough water to support new young plants. As the climate changes, long periods of drought are likely to occur with more frequency, leading to issues with the trees like those already observed.

An additional finding of this study is that in the cooler, wetter parts of the park the biggest threat other than climate change is fire. Fewer than 10 percent of Joshua trees survive wildfires, which have been exacerbated in recent years by smog from car and industrial exhaust. The smog deposits nitrogen on the ground, which in turn feeds non-native grasses that act as kindling for wildfires.

As a partner on this project, the U.S. Park Service is using this information to mitigate fire risk by removing the invasive plants.

"Fires are just as much a threat to the trees as climate change, and removing grasses is a way park rangers are helping to protect the area today," Sweet said. "By protecting the trees, they're protecting a host of other native insects and animals that depend on them as well."

UCR animal ecologist and paper co-author Cameron Barrows conducted a similar research project in 2012, which also found Joshua tree populations would decline, based on models assuming a temperature rise of three degrees. However, this newer study considered a climate change scenario using twice as many variables, including soil-water estimates, rainfall, soil types, and more. In addition, Barrows said on-the-ground observations were essential to verifying the climate models this newer team had constructed.

Quoting the statistician George Box, Barrows said, "All models are wrong, but some are useful." Barrows went on to say, "Here, the data we collected outdoors showed us where our models gave us the most informative glimpse into the future of the park."

For this study, the UC Riverside Center for Conservation Biology partnered with Earthwatch Institute to recruit the volunteer scientists. Barrows and Sweet both recommend joining such organizations as a way to help find solutions to the park's problems.

"I hope members of the public read this and think, 'Someone like me could volunteer to help scientists get the kind of data that might lend itself to concrete, protective actions,'" Barrows said.

For many women of reproductive age, the most common way of assessing their menstrual health and fertility means regular visits to a gynecologist or another clinician. When it comes to evaluating changes in fertility, menstrual health, and quality of life, these visits typically rely on remembering, which can lead to significant inaccuracies in evaluation.

On the other hand, many women today are turning to so-called "fertility awareness method" (FAM) apps to support them in tracking their menstrual cycles. There is a multitude of such apps available, which only demonstrates how popular they've become in recent years.

But how accurate are FAM apps? What do users track? Can they help them and their gynecologists? These are hard to answer for a simple reason: Neither visits nor app use have been systematically studied on a population level to determine and compare their accuracy in evaluating menstrual health and fertility in a meaningful way.

This is what Laura Symul at EPFL's Digital Epidemiology Lab has done. Working with Stanford University (which she has now joined), Symul led a large-scale study on 200,000 users of two FAM apps, Sympto and Kindara. Both apps support the "Sympto-Thermal Method" and facilitate the identification of the fertile and infertile times of a woman's menstrual cycle by taking into account recordings of cervical fluid, body temperature at wake-up, and other biological signs.

The scientists tracked more than 30 million days of observations from over 2.7 million menstrual cycles. The overall study had two aims: First, to see how and what users voluntarily track on FAM apps. Second, to find out if these records allow an accurate detection and estimation of ovulation timing.

In terms of user demographics and behavior, the study found that the typical FAM app user is around 30 years old, lives in a western country (in Europe or Northern America) and has a healthy BMI. App users log their observations more frequently when they also log sexual intercourse, and when you look at them on a population level, reported fertility awareness body signs exhibit temporal patterns that follow very closely those that have been found in small-scale clinical studies.

Analyzing the data, the scientists found that women who were seeking pregnancy recorded Sympto-Thermal measurements every single day for up to 40% of their menstrual cycles. Then, by modeling the data, they found that the average duration and range of the follicular phase, which begins the menstrual cycle and ends at ovulation, were larger than previously reported. In fact, the modeling showed that only 24% of ovulations occur at days 14 to 15 of the cycle. On the other hand, the data showed that the duration and range of the luteal phase - the latter part of the menstrual cycle - matched previous studies.

The findings offer an affordable means for studying the interactions between the menstrual cycle and other physiological systems on a large scale. "Our study provides a common ground for users and their doctors to incorporate digital records in their visits, evaluate their own menstrual patterns and compare them with the statistics we report," says Laura Symul.

She continues: "New technologies, and in particular self-tracking, are changing the way we perceive our bodies and health. Both users and doctors wonder about the opportunities and the usefulness of digital self-tracking. Our study shows that users voluntarily track their menstrual cycle and fertility-related body signs very frequently, and what they track is aligned with what is expected in the vast majority of cases. While these measurements and observations are noisy and not perfectly regular, they provide valuable information for inferring the underlying hormonal changes and timing of ovulation in a way that is scalable both in time and in number of participants."

Marcel Salathé, director of the Digital Epidemiology Lab adds: "The digital epidemiology approach presented here can help to lead to a better understanding of menstrual health and its connection to women's health overall, which has historically been severely under-studied."

Financial incentives work to help people stop smoking and remain smoke free - according to research led by the University of East Anglia (UEA).

Evidence published today in the Cochrane Library provides strong evidence that financial incentives helped people to stop smoking, and stay stopped long term.

The review also found that incentives helped pregnant women stop smoking.

Lead author Dr Caitlin Notley, from UEA's Norwich Medical School, said: "Smoking is the leading cause of disease and death worldwide. Most smokers want to quit, but stopping smoking can be really challenging.

"Quitting smoking can greatly improve peoples' health. Rewards, such as money or vouchers, have been used to encourage smokers to quit, and to reward them if they stay stopped. Such schemes have been used in workplaces, in clinics and hospitals, and within community programmes.

"We wanted to know whether these schemes actually work long term, as previously it was thought that perhaps incentives only worked for the time that they were given. We found that they do help people stay smoke free, even after the incentive scheme ends.

"The cost of smoking to the economy is huge - around £13 billion to the UK economy, including over £3 billion for NHS and social care and £7.5 billion to lost productivity. So these types of schemes could help save money as well as lives."

The team investigated whether rewards such as cash payments, vouchers, or the return of money deposited by those taking part, worked. The review summarizes the results from 33 randomised controlled trials involving more than 21,600 people from eight countries. They included ten trials that focused on pregnant smokers who were rewarded with vouchers for quitting and staying smoke free.

All of the trials in the general population followed participants for at least six months and those who quit were checked by testing their breath or bodily fluids.

Some of the studies did not provide enough data for the team to fully assess their quality. But taking out the lowest quality trials from the analysis did not change the results.

The researchers say that the certainty of their findings in the general population is high. Their certainty about the findings in pregnant women is moderate, as there weren't as many studies and some were lower quality.

Dr Notley said: "We found that six months or more after the beginning of the trials, people receiving rewards were approximately 50 per cent more likely to have stopped smoking than those in the control groups.

"In people not receiving incentives, approximately seven per cent had successfully quit for six months or longer, compared to approximately 10.5 per cent of those receiving incentives.

"This is an important increase when we consider the enormous harms of smoking, and benefits of quitting, and suggests that incentives can be a useful part of a comprehensive approach to help people quit smoking. Another really important thing is that success rates continued beyond when the incentives had ended."

The total financial amount of incentives varied considerably between trials, from zero (self-deposits), to a range of between £35 ($45 USD) and £912 ($1185).

Dr Notley added: "For pregnant women, we also found that women in the rewards groups were more likely to stop smoking than those in control groups - both at the end of the pregnancy and after the birth of the baby, suggesting incentives may be a useful part of a comprehensive approach to helping pregnant women quit smoking.

"Stopping smoking during pregnancy is the best thing that women can do to improve their chances of having a healthy pregnancy. Staying stopped after the birth has great benefits for babies too, through avoiding exposure to second hand smoke."

A new paper details how small samples of ubiquitous building materials, such as tile or brick, can be used to test whether a facility has ever stored high enriched uranium (HEU), which can be used to create nuclear weapons. The technique could serve as a valuable forensic tool for national or international efforts related to nuclear nonproliferation and security.

"We can now use the housing structure itself as part of any nonproliferation monitoring efforts," says Robert Hayes, an associate professor of nuclear engineering at North Carolina State University and author of the paper. "This work details the theory to test building material samples to differentiate between the forms of uranium used in nuclear power and the HEU that's used to develop nuclear weapons."

The technique builds on previous work done by Hayes and his research team.

The method requires testing a relatively small core sample of the relevant building material, about the size of your pinkie finger. The testing is done using hardware somewhat similar to that used to assess radiation exposure of dosimeter badges worn by workers in the nuclear power industry. In a sense, a small piece of any wall effectively becomes a dosimeter badge.

"Our technique allows us to determine how much radiation a material has been exposed to, in addition to the very types of radiation a material has been exposed to," Hayes says. "Because different radionuclides have different radiation fields, these measurements allow us to determine which nuclear materials were stored near whatever building material we're sampling."

While this technique is new, there is already interest in it among the agencies responsible for nuclear monitoring - and Hayes is working to improve the technique further.

"We're optimistic that this will be a valuable tool in the nonproliferation monitoring toolbox, but we need to address some existing questions," Hayes says.

"For example, the radiation signature will vary depending on where the nuclear material was stored in relation to whatever sample we're testing. If our sample was from brick that was right under a uranium storage container, the signature will be different than if the container was located 20 feet away, horizontally. Theoretically, these properties of the signature would be consistent over any gridded array of the same building material. Sampling such an array would then allow us to reconstruct not only what material was stored at a site, but precisely where it was stored. That's something we're working on now."

Removing new neurons born after a brain injury reduces seizures in mice, according to new research in JNeurosci. This approach could potentially help prevent post-injury epilepsy.

New neurons generated following a brain injury often do not develop normally. Left untreated, these cells may contribute to the development of epilepsy.

Jenny Hsieh and colleagues at the University of Texas at San Antonio continually removed new neurons that formed during the eight weeks following a seizure in mice. Hsieh's team monitored seizure activity in the mice and observed that the treated mice experienced a 65 percent reduction in seizures compared to the untreated mice. This effect required more than four weeks of continuous treatment.

Although these findings support a role for newborn neurons in epilepsy development, they also suggest additional factors are involved. Further research may bring us closer to complete prevention of injury-induced epilepsy.

A five-year collaborative study by Chinese and Canadian scientists has produced a theoretical model via computer simulation to predict properties of hydrogen nanobubbles in metal.

The international team was composed of Chinese scientists from the Institute of Solid State Physics of the Hefei Institute of Physical Science along with their Canadian partners from McGill University. The results will be published in Nature Materials on July 15.

The researchers believe their study may enable quantitative understanding and evaluation of hydrogen-induced damage in hydrogen-rich environments such as fusion reactor cores.

Hydrogen, the most abundant element in the known universe, is a highly anticipated fuel for fusion reactions and thus an important focus of study.

In certain hydrogen-enriched environments, e.g., tungsten armor in the core of a fusion reactor, metallic material may be seriously and irreparably damaged by extensive exposure to hydrogen.

Being the smallest element, hydrogen can easily penetrate metal surfaces through gaps between metal atoms. These hydrogen atoms can be readily trapped inside nanoscale voids ("nanovoids") in metals created either during manufacturing or by neutron irradiation in the fusion reactor. These nanobubbles get bigger and bigger under internal hydrogen pressure and finally lead to metal failure.

Not surprisingly, the interplay between hydrogen and nanovoids that promote the formation and growth of bubbles is considered the key to such failure. Yet, the basic properties of hydrogen nanobubbles, such as their number and the strength of the hydrogen entrapped in the bubbles, has largely been unknown.

Furthermore, available experimental techniques make it practically impossible to directly observe nanoscale hydrogen bubbles.

To tackle this problem, the research team proposed instead using computer simulations based on fundamental quantum mechanics. However, the structural complexity of hydrogen nanobubbles made numerical simulation extremely complicated. As a result, the researchers needed five years to produce enough computer simulations to answer their questions.

In the end, however, they discovered that hydrogen trapping behavior in nanovoids - although apparently complicated - actually follows simple rules.

First, individual hydrogen atoms are adsorbed, in a mutually exclusive way, by the inner surface of nanovoids with distinct energy levels. Second, after a period of surface adsorption, hydrogen is pushed - due to limited space - to the nanovoid core where molecular hydrogen gas then accumulates.

Following these rules, the team created a model that accurately predicts properties of hydrogen nanobubbles and accords well with recent experimental observations.

Just as hydrogen fills nanovoids in metals, this research fills a long-standing void in understanding how hydrogen nanobubbles form in metals. The model provides a powerful tool for evaluating hydrogen-induced damage in fusion reactors, thus paving the way for harvesting fusion energy in the future.

Barry, now a tropical depression, continues moving slowly north through Arkansas and rainfall and flooding remains a concern. NASA-NOAA's Suomi NPP satellite passed over the south central United States yesterday, July 14 and captured a visible image of then Tropical Storm Barry.

Tropical Storm Barry tracked through northwestern Louisiana on July 14, and weakened to a tropical depression. On its track, Barry dropped up to 15 inches (38 cm) of rain in some isolated placed. Barry's rainfall created flooding along the Mississippi River.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of the storm on July 14 after it moved inland over Louisiana. The VIIRS image showed an elongated storm over Louisiana stretching over the Mississippi River Valley and into Arkansas, Mississippi, western Alabama and southwestern Tennessee.

On July 15, NOAA's National Weather Service Weather Prediction Center in College Park, Maryland said that local flash flooding remains a likely threat through the day. Flash Flood Watches and Warnings are in effect for portions of far southeast Texas through much of Louisiana, Mississippi and Arkansas, and including parts of the mid-Mississippi Valley. Barry is expected to produce additional rain accumulations of 2 to 4 inches with isolated maximum amounts of 8 inches across Arkansas, western Tennessee and Kentucky, southeast Missouri, and northwest Mississippi.

At 5 a.m. EDT (0900 UTC), the center of Tropical Depression Barry was located near latitude 34.4 degrees north and longitude 93.5 degrees west. That's about 80 miles (125 km) west-southwest of Little Rock Arkansas. The depression is moving toward the north near 9 mph (15 kph) and this motion is expected to continue through today, before turning off to the northeast by Tuesday. Maximum sustained winds are near 25 mph (35 kph) with higher gusts. Little change in strength is forecast during the next 48 hours. The estimated minimum central pressure is 1008 millibars (29.77 inches).

In addition to the heavy rainfall, the National Weather Service noted, "A couple of tornadoes are possible today from the Mid-South toward the Lower Ohio Valley."

For river flood forecasts, visit: https://water.weather.gov/ahps/

By Rob Gutro
NASA's Goddard Space Flight Center

A new large-scale genome-wide association study published in Nature Genetics, has identified eight genetic variants significantly associated with anorexia nervosa; and the research shows that the origins of this serious disorder appear to be both metabolic and psychiatric.

Anorexia nervosa is a life-impairing illness characterized by dangerously low body weight, an intense fear of gaining weight, and a lack of recognition of the seriousness of the low body weight. Anorexia nervosa has the highest mortality rate of any psychiatric illness, according to the National Center of Excellence for Eating Disorders.

"Until now, our focus has been on the psychological aspects of anorexia nervosa such as the patients' drive for thinness. Our findings strongly encourage us to also shine the torch on the role of metabolism to help understand why individuals with anorexia frequently drop back to dangerously low weights, even after therapeutic renourishment. A failure to consider the role of metabolism may have contributed to the poor track record among health professionals in treating this illness," said principal investigator Cynthia M. Bulik, PhD, FAED, founding director of the UNC Center of Excellence for Eating Disorders and Distinguished Professor in the Department of Psychiatry in the UNC School of Medicine.

For the study, Bulik and a multinational group of more than 100 researchers combined data collected by the Anorexia Nervosa Genetics Initiative (ANGI) and the Eating Disorders Working Group of the Psychiatric Genomics Consortium (PGC-ED). The resulting data set included 16,992 anorexia nervosa cases and 55,525 controls of European ancestry from 17 countries across North America, Europe, and Australasia.

Other findings of the study include:

The genetic basis of anorexia nervosa overlaps with other psychiatric disorders such as obsessive-compulsive disorder, depression, anxiety, and schizophrenia.

Genetic factors associated with anorexia nervosa also influence physical activity, which could help explain the tendency for people with anorexia nervosa to be highly active.

Intriguingly, the genetic basis of anorexia nervosa overlaps with metabolic (including glycemic), lipid (fats), and anthropometric (body measurement) traits, and the study shows that this is not due to genetic effects that influence BMI.

Dr. Gerome Breen of King's College London, who co-led the study said, "Metabolic abnormalities seen in patients with anorexia nervosa are most often attributed to starvation, but this study shows they may also contribute to the development of the disorder. These results suggest that genetic studies of eating disorders may yield powerful new clues about their causes and may change how we approach and treat anorexia."

The study concludes that anorexia nervosa may be a 'metabo-psychiatric disorder' and that it will be important to consider both metabolic and psychological risk factors when exploring new avenues for treating this potentially lethal illness.

Researchers from over 100 institutions worldwide participated in the study.