Dr Rocio Hernandez-Clemente, a senior lecturer from the University’s Department of Geography, joined an international team of researchers from the Dryland Ecology and Global Change Lab at the University of Alicante to examine the Earth’s dryland ecosystem, which covers 41% of the world’s surface and is home to around a third of its population.

The study found for the first time that as aridity increases, dryland ecosystems undergo a series of abrupt changes. This results first in drastic reductions in the capacity of plants to fix carbon from the atmosphere, followed by substantial declines of soil fertility and ending with the disappearance of vegetation under the most arid and extreme conditions.

Climate change and ecosystems

The team found that increases in aridity in line with current climate change forecast, led to abrupt shifts in dryland ecosystems worldwide which limit their capacity to sustain life. This is because climate largely determines the amount and types of plants that can be found in a given place, how fertile the soil is, and how the landscapes look like. Understanding how changes in climatic conditions affect organisms and the ecosystem processes and services that depend on them, such as food and biomass production, is key to understanding, forecasting and mitigating climate change impacts on both ecosystems and societies.

The study

The team led by Dr. Miguel Berdugo, at the University of Alicante, pulled together the largest compilation of empirical data to date to evaluate how key ecosystems change along the wide aridity gradients that can be found in drylands worldwide. Dr Hernandez-Clemente performed the data extraction, processing and Normalized Difference Vegetation Index data analysis of 60000 points distributed worldwide and used as an indicator of plant productivity in drylands. She also contributed to the quality assessment analysis and validation of the data and derived trends to detect abrupt shifts through remote sensing data.

Dr. Berdugo said: “The purpose of our work was to look at how these ecosystem change as we move towards more arid zones in order to better understand what we may expect in the future as the climate becomes drier, and more arid, in drylands worldwide.”

The study identified three phases of accelerated ecosystem change in response to increases in aridity, measured as the inverse ratio between rainfall and the rate by which water evaporates from the land to the atmosphere.

Key findings

The key findings of the study were:

• If aridity increases just a small amount of 0.5, there are rapid and often abrupt ecosystem changes
• The landscape changes and is dominated by species adapted to more arid conditions and drought.
• If aridity increases by 0.7, soil loses its structure and becomes more vulnerable to erosion.
• Soil organisms that play essential roles in maintaining ecosystem functioning are also negatively affected.
• There are large increases in the presence of pathogens at the expense of more beneficial organisms.
• If aridity levels are raised beyond a threshold of 0.8, the system collapses, plants cannot thrive and the land becomes desert.

According to climatic forecasts, more than 20% of land may cross one or several of the thresholds identified in this study by 2100 due to climate change.

Dr Berdugo said: “Life will not disappear from drylands with forecasted aridity increases, but our findings suggest that their ecosystems may experience abrupt changes that will reduce their capacity to provide ecosystem services more than 2 billion people, such as soil fertility and biomass production.”

Dr Rocio Hernandez-Clemente said: “The reduced global ability of the land to sustain life is predicted to become an increasing problem with climate change. This study demonstrates the possibility of detecting abrupt changes and monitoring how land turns into desertification processes with remote sensing data.

“The use of satellite image data helps scientists to monitor, predict and quantify the consequences of the increasing aridity in drylands ecosystems worldwide. International cooperation is essential for assessing land degradation and abrupt shifts. The next steps of our research will be focused in the use of earth observation data for look for changes of desertification processes.”

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Unfortunately, hunting not only depletes the flying foxes, which are already rare, but also potentially exposes humans to animal-borne pathogens (a process known as zoonosis). “For instance, the current case of Wuhan Coronavirus is thought to have been spread from wild bats to humans through an intermediate host at a wildlife market,” said CCNY biologist and Tsang’s mentor David J. Lohman, an entomologist and two-time Fulbright recipient.

The CCNY experts found that flying foxes originated in a group of islands in Indonesia called Wallacea. They diversified into different species by flying to other islands that presumably lacked competitors and established themselves. Thus, islands are critical to the evolution and conservation of this large group of around 65 mammal species.

“This study provides insight into biodiversity conservation and public health. Islands are frequently home to endemic species found nowhere else,” noted Tsang, who earned a PhD in biology from the Graduate Center, CUNY.

Unfortunately, island-endemic species are more likely to be endangered or go extinct than continental species. Flying foxes are seed dispersers and pollinators of many ecologically and economically important plants, and forest trees on islands often depend on bats for regeneration.

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In a new paper researchers from the Max Planck Institute for Evolutionary Anthropology and the University of Vienna measured the magnitude and pattern of shape asymmetry of endocasts from humans and apes. “Great ape brains are rarely available for study, but we have developed methods to extract brain asymmetry data from skulls, which are easier to access. This made our study possible in the first place,” says lead author Simon Neubauer.

The team found that the magnitude of asymmetry was about the same in humans and most great apes. Only chimpanzees were, on average, less asymmetric than humans, gorillas, and orangutans. They also investigated the pattern of asymmetry and could demonstrate that not only humans, but also chimpanzees, gorillas, and orangutans showed the asymmetry pattern previously described as typically human: the left occipital lobe, the right frontal lobe, as well as the right temporal pole and the right cerebellar lobe projecting more relatively to their contralateral parts. “What surprised us even more,” says Philipp Mitteroecker, a co-author of the study, “was that humans were least consistent in this asymmetry with a lot of individual variation around the most common pattern.” The authors interpret this as a sign of increased functional and developmental modularization of the human brain. For example, the differential projections of the occipital lobe and the cerebellum are less correlated in humans than in great apes. This finding is interesting because the cerebellum in humans underwent dramatic evolutionary changes and it seems that thereby its asymmetry was affected as well.

The finding of a shared asymmetry pattern but greater variability in humans is intriguing for the interpretation of human brain evolution. An endocast of one of our fossil ancestors that shows this asymmetry can no longer be interpreted as evidence for human-specific functional brain lateralization without other (archaeological) data. Philipp Gunz, a co-author of the study, explains: “This shared asymmetry pattern of the brain evolved already before the origin of the human lineage. Humans seem to have built upon this morphological pattern to establish functional brain lateralization related to typical human behaviors.”

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Now MIT researchers have developed a “smart” diaper embedded with a moisture sensor that can alert a caregiver when a diaper is wet. When the sensor detects dampness in the diaper, it sends a signal to a nearby receiver, which in turn can send a notification to a smartphone or computer.

The sensor consists of a passive radio frequency identification (RFID) tag, that is placed below a layer of super absorbent polymer, a type of hydrogel that is typically used in diapers to soak up moisture. When the hydrogel is wet, the material expands and becomes slightly conductive — enough to trigger the RFID tag to send a radio signal to an RFID reader up to 1 meter away.

The researchers say the design is the first demonstration of hydrogel as a functional antenna element for moisture sensing in diapers using RFID. They estimate that the sensor costs less than 2 cents to manufacture, making it a low-cost, disposable alternative to other smart diaper technology.

Over time, smart diapers may help record and identify certain health problems, such as signs of constipation or incontinence. The new sensor may be especially useful for nurses working in neonatal units and caring for multiple babies at a time.

Pankhuri Sen, a research assistant in MIT’s AutoID Laboratory, envisions that the sensor could also be integrated into adult diapers, for patients who might be unaware or too embarrassed to report themselves that a change is needed.

“Diapers are used not just for babies, but for aging populations, or patients who are bedridden and unable to take care of themselves,” Sen says. “It would be convenient in these cases for a caregiver to be notified that a patient, particularly in a multibed hospital, needs changing.”

“This could prevent rashes and some infections like urinary tract infections, in both aging and infant populations,” adds collaborator Sai Nithin R. Kantareddy, a graduate student in MIT’s Department of Mechanical Engineering.

Sen, Kantareddy, and their colleagues at MIT, including Rahul Bhattacharryya and Sanjay Sarma, along with Joshua Siegel at Michigan State University, have published their results today in the journal IEEE Sensors. Sarma is MIT’s vice president for open learning and the Fred Fort Flowers and Daniel Fort Flowers Professor of Mechanical Engineering.

Sticker sense

Many off-the-shelf diapers incorporate wetness indicators in the form of strips, printed along the outside of a diaper, that change color when wet — a design that usually requires removing multiple layers of clothing to be able to see the actual diaper.

Companies looking into smart diaper technology are considering wetness sensors that are wireless or Bluetooth-enabled, with devices that attach to a diaper’s exterior, along with bulky batteries to power long-range connections to the internet. These sensors are designed to be reusable, requiring a caregiver to remove and clean the sensor before attaching it to each new diaper. Current sensors being explored for smart diapers, Sen estimates, retail for over $40.

RFID tags in contrast are low-cost and disposable, and can be printed in rolls of individual stickers, similar to barcode tags. MIT’s AutoID Laboratory, founded by Sarma, has been at the forefront of RFID tag development, with the goal of using them to connect our physical world with the internet.

A typical RFID tag has two elements: an antenna for backscattering radio frequency signals, and an RFID chip that stores the tag’s information, such as the specific product that the tag is affixed to. RFID tags don’t require batteries; they receive energy in the form of radio waves emitted by an RFID reader. When an RFID tag picks up this energy, its antenna activates the RFID chip, which tweaks the radio waves and sends a signal back to the reader, with its information encoded within the waves. This is how, for instance, products labeled with RFID tags can be identified and tracked.

Sarma’s group has been enabling RFID tags to work not just as wireless trackers, but also as sensors. Most recently, as part of MIT’s Industrial Liason Program, the team started up a collaboration with Softys, a diaper manufacturer based in South America, to see how RFID tags could be configured as low-cost, disposable wetness detectors in diapers. The researchers visited one of the company’s factories to get a sense of the machinery and assembly involved in diaper manufacturing, then came back to MIT to design a RFID sensor that might reasonably be integrated within the diaper manufacturing process.

Tag, you’re it

The design they came up with can be incorporated in the bottom layer of a typical diaper. The sensor itself resembles a bow tie, the middle of which consists of a typical RFID chip connecting the bow tie’s two triangles, each made from the hydrogel super absorbent polymer, or SAP.

Normally, SAP is an insulating material, meaning that it doesn’t conduct current. But when the hydrogel becomes wet, the researchers found that the material properties change and the hydrogel becomes conductive. The conductivity is very weak, but it’s enough to react to any radio signals in the environment, such as those emitted by an RFID reader. This interaction generates a small current that turns on the sensor’s chip, which then acts as a typical RFID tag, tweaking and sending the radio signal back to the reader with information — in this case, that the diaper is wet.

The researchers found that by adding a small amount of copper to the sensor, they could boost the sensor’s conductivity and therefore the range at which the tag can communicate to a reader, reaching more than 1 meter away.

To test the sensor’s performance, they placed a tag within the bottom layers of newborn-sized diapers and wrapped each diaper around a life-sized baby doll, which they filled with saltwater whose conductive properties were similar to human bodily fluids. They placed the dolls at various distances from an RFID reader, at various orientations, such as lying flat versus sitting upright. They found that the particular sensor they designed to fit into newborn-sized diapers was able to activate and communicate to a reader up to 1 meter away when the diaper was fully wet.

Sen envisions that an RFID reader connected to the internet could be placed in a baby’s room to detect wet diapers, at which point it could send a notification to a caregiver’s phone or computer that a change is needed. For geriatric patients who might also benefit from smart diapers, she says small RFID readers may even be attached to assistive devices, such as canes and wheelchairs to pick up a tag’s signals.

This research was supported in part by Softys under the MIT Industry Liaison Program.

In a study featured as the cover article appearing today in the journal Science Advances, a UCF research team showed that by combining two promising nanomaterials into a new superstructure, they could create a nanoscale device that mimics the neural pathways of brain cells used for human vision.

“This is a baby step toward developing neuromorphic computers, which are computer processors that can simultaneously process and memorize information,” said Jayan Thomas, an associate professor in UCF’s NanoScience Technology Center and Department of Materials Science and Engineering. “This can reduce the processing time as well as the energy required for processing. At some time in the future, this invention may help to make robots that can think like humans.”

Thomas led the research in collaboration with Tania Roy, an assistant professor in UCF’s NanoScience Technology Center, and others at UCF’s NanoScience Technology Center and the Department of Materials Science and Engineering.

Roy said a potential use for the technology is for drone-assisted rescues.

“Imagine a drone that can fly without guidance to remote mountain sites and locate stranded mountaineers,” Roy said. “Today it is difficult since these drones need connectivity to remote servers to identify what they scan with their camera eye. Our device makes this drone truly autonomous because it can see just like a human.”

“Earlier research created a camera which captured the image and sent it to a server to be recognized, but our group created a single device that mimics the eye and the brain function together,” she said. “Our device can observe the image and recognize it on the spot.”

The trick to the innovation was growing nanoscale, light-sensitive perovskite quantum dots on the two-dimensional, atomic thick nanomaterial graphene. This combination allows the photoactive particles to capture light, convert it to electric charges and then have the charges directly transferred to the graphene, all in one step. The entire process takes place on an extremely thin film, about one-ten thousandths of the thickness of a human hair.

Basudev Pradhan, who was a Bhaskara Advanced Solar Energy fellow in Thomas’ lab and is currently an assistant professor in the Department of Energy Engineering at the Central University of Jharkhand in India, and Sonali Das, a postdoctoral fellow in Roy’s lab, are shared first authors of the study.

“Because of the nature of the superstructure, it shows a light-assisted memory effect,” Pradhan said. “This is similar to humans’ vision-related brain cells. The optoelectronic synapses we developed are highly relevant for brain-inspired, neuromorphic computing. This kind of superstructure will definitely lead to new directions in development of ultrathin optoelectronic devices.”

Das said there are also potential defense applications.

“Such features can also be used for aiding the vision of soldiers on the battlefield,” she said. “Further, our device can sense, detect and reconstruct an image along with extremely low power consumption, which makes it capable for long-term deployment in field applications.”

Neuromorphic computing is a long-standing goal of scientists in which computers can simultaneously process and store information, like the human brain does, for example, to allow vision. Currently, computers store and process information in separate places, which ultimately limits their performance.

To test their device’s ability to see objects through neuromorphic computing, the researchers used it in facial recognition experiments, Thomas said.

“The facial recognition experiment was a preliminary test to check our optoelectronic neuromorphic computing,” Thomas said. “Since our device mimics vision-related brain cells, facial recognition is one of the most important tests for our neuromorphic building block.”

They found that their device was able to successfully recognize the portraits of four different people.

The researchers said they plan to continue their collaboration to refine the device, including using it to develop a circuit-level system.