Experts in the News

Georgia Tech researchers developed a neural network, RTNet, that mimics human decision-making processes, including confidence and variability, improving its reliability and accuracy in tasks like digit recognition. Working in the lab of Associate Professor Dobromir Rahnev in the School of Psychology, researchers are training neural networks to make decisions more like humans. This science of human decision-making is only just being applied to machine learning, but developing a neural network even closer to the actual human brain may make it more reliable.

Over the past few decades, earth scientists have grappled with the concept of solar geoengineering: cooling the rapidly warming planet by injecting particles high into the atmosphere to reflect sunlight, for example. Now, researchers are proposing a new way to battle the effects of climate change that could prove even more costly and controversial: glacial geoengineering, designed to slow sea level rise.

A white paper, released on 11 July by glaciologists, calls for boosting research into daring plans that would protect vulnerable ice sheets by building flexible barriers around them or drilling deep into them to slow their slippage into the sea.

These untested ideas are stirring up a backlash among glaciologists, some of whom view them not only as outlandishly expensive and logistically flawed but also as a distraction from the problem of reducing greenhouse gas emissions. In an article in Science, scientists, including School of Earth and Atmospheric Sciences Associate Professor Alex Robel, discuss the white paper and the distinction between supporting geoengineering and supporting its research. “I think the reality is that most people who will end up engaging in geoengineering research will do so because it increases the likelihood that geoengineering will actually happen,” says Robel.

On the timescale of sensory processing, neuronal networks have relatively fixed anatomical connectivity, while functional interactions between neurons can vary depending on the ongoing activity of the neurons within the network. In a paper published in Nature Communications, a team of researchers, including School of Mathematics Assistant Professor Hannah Choi, hypothesizes that different types of stimuli could lead those networks to display stimulus-dependent functional connectivity patterns. The team analyzed single-cell resolution electrophysiological data from the Allen Institute, with simultaneous recordings of stimulus-evoked activity from neurons across 6 regions of the mouse visual cortex. The work reveals unexpected stimulus-dependence regarding the way groups of neurons interact to process incoming sensory information.

Every few seconds, somewhere in the observable Universe, a massive star collapses and unleashes a supernova explosion. Physicists say Japan’s Super-Kamiokande (Super-K) observatory might now be collecting a steady trickle of neutrinos from those cataclysms — amounting to a few detections a year.

In an article published in Nature, School of Physics Professor Ignacio Taboada provides a brief commentary on this new research: "The data from Super-K are still too weak to claim a discovery, but the prospect of detecting the diffuse neutrinos is extremely exciting”, says Tabaoda, who is also the spokesperson for the IceCube neutrino observatory at the South Pole. “Neutrinos would provide an independent measurement on the history of star formation in the Universe.”

Groundbreaking research is shedding new light on how biofilms grow — using physics and mathematical models. Biofilms grow everywhere — from plaque on teeth, to medical devices, to the open ocean. But until now, it’s been difficult to study just what controls their growth. In a new study published in Nature Physics, researchers from the Yunker Lab in the School of Physics, including Lead Researcher Aawaz Pokhrel and Associate Professor Peter Yunker, leveraged physics to show that a biofilm’s geometry is the single most important factor in determining growth rate — more important than even the rate at which cells can reproduce. Since some research shows that 80% of infections in human bodies are caused by the bacteria in biofilms, understanding how colonies grow has important human health implications, potentially to help reduce their impact in medical settings or industrial processes. (This also appeared in Phys.org and Dental Review News.)

Recent demonstrations of moiré magnetism, featuring exotic phases with noncollinear spin order in the twisted van der Waals (vdW) magnet chromium triiodide CrI3, have highlighted the potential of twist engineering of magnetic (vdW) materials. In this paper, researchers, including School of Physics assistant professors Hailong Wang and Chunhui Du, reported the observation of two distinct magnetic phase transitions with separate critical temperatures within a moiré supercell of small-angle twisted double trilayer CrI3.

A team of researchers, led by Georgia Tech alumna Feifei Qian and School of Earth and Atmospheric Sciences Assistant Professor Frances Rivera-Hernández, continue to work on the LASSIE Project, which stands for Legged Autonomous Surface Science in Analogue Environments. They want to see just how well a four-legged robot could make it up Mount Hood’s gravel and snow. “It’s literally a robotic dog form,” said Qian. “It can plow. It can basically dig a hole.” She added, "the information the robot sends back with each step could tell scientists whether it’s good to build a structure in a certain spot on the moon or whether it’d be good to excavate."

A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. In this article, a team of researchers, including School of Earth and Atmospheric Sciences Postdoctoral Scholar Devon Cole, combined approaches from statistical learning, biogeochemical modeling and ecophysiology to better constrain changes in global ocean biogeochemistry and marine animal habitats through the Neoproterozoic and Palaeozoic eras.

With global ocean heat at record levels, scientists have confirmed that a global coral bleaching event is underway. In an article published in The Conversation, School of Earth and Atmospheric Sciences Professor Annalisa Bracco discusses how research on reef connectivity and resilience may open new avenues for helping corals survive. 

An article published in NewScientist reveals that Antarctica’s melting ice sheets may retreat faster than previously thought. Scientists from the British Antarctic Survey and the University of Oxford discovered that Antarctica’s melting ice sheets may retreat more quickly as warm seawater intrudes underneath them, leading to more melting and faster sea level rise. 

Their findings are built off a model developed by School of Earth and Atmospheric Sciences Associate Professor Alexander Robel and other researchers. Robel’s model found extensive intrusions could more than double the amount of ice loss from an ice sheet by adding heat from below and lubricating the flow of ice along the bedrock. “That positive feedback can cause there to be much more intrusion than we thought possible,” says Robel. “Whether that will be a tipping point that will lead to unrestrained incursion of seawater under the ice sheet – that’s probably a stretch.”

An observatory still under construction at the bottom of the Mediterranean Sea has spotted what could be the most energetic neutrino ever detected. Such ultra-high-energy neutrinos — tiny subatomic particles that travel at nearly the speed of light — have been known to exist for only a decade or so, and are thought to be messengers from some of the Universe’s most cataclysmic events, such as growth spurts of supermassive black holes in distant galaxies. “It would be really interesting to see where in the sky the neutrino originated,” says Nepomuk Otte, an associate professor in the School of Physics. Otte is leading a proposed project — with a prototype now being tested in Utah — that would search for Earth-skimming neutrinos by monitoring the atmosphere just above the horizon for flashes of light.

Frequently wearing high heels could help you walk more efficiently in flat shoes, according to a new study published in The Journal of Applied Physiology. Researchers at the University of Texas at Austin and Georgia Institute of Technology, including Gregory S. Sawicki, associate professor in the School of Biological Sciences and the School of Mechanical Engineering, found that donning stilettos could help strengthen the tendons in the ankles and calves, making the legs more powerful.