Researchers from the University of Nottingham have for the first time used a path of assembled molecules liquids that travelling molecules can be propelled along by light. The research ‘Light-controlled micron-scale molecular motion’ has been published today in Nature Chemistry.

Professor David Amabilino from the School of Chemistry at the University of Nottingham is one of the lead researchers, he explains: “In living organisms, molecular motors travel along specific molecular paths, it is an essential part of cell function. We have shown that a synthetic self-made molecular fibre in a liquid behaves like a path for the movement of a molecular traveller over a distance 10,000 times its length. Light acts as the fuel to encourage the motion, while a molecular switch mixed into the system apparently propels the traveller on its way.

The system emulates, for the first time, movement of the kind taking place along fibres in cells. This is a very exciting discovery as If we can find ways to make use of the light’s potential in this process then it could pave the way for use in light activated medicines, new ways to harness light energy as a source of power and to create new sustainable ways to carry out chemical tasks.”

The team used interactions between oppositely charged chemical groups and created motion to this static system by introducing a switching molecule, that flaps back and forth quite quickly, into the fibres. Shining a light onto this weakens the traveller molecules interaction with the path as they move along it, which can be at some distance. If the molecule were our size, they would move the equivalent of 10 km.

Heat is released when the switching molecules are irradiated, and that heat has a local effect that helps the traveller move, so the mechanical movement of the switch, and the heat that is released when it does, are important for making the system work.

The technique the team used to observe these effects is a special optical microscope that allowed the simultaneous exciting of the molecules — making them move — and observation of them as they give light back out (the travelling molecules are fluorescent).

Co-author on the study Mario Samperi adds: “The system we have prepared is very sensitive to the solvent in which the fibres are formed. In a liquid about the strength of strong whisky, the travelling molecules move along the fibres to another location, whereas when the liquid is the strength of weaker limoncello, rings of rearranged fibres are formed where the travellers have moved along and incorporated into the newly formed circular track.

We want to be able to transport other molecules from one place to another in a controlled way, so that the travelling molecules can carry a package from one place to another, emulating nature, but using light as energy.”

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In a recently published paper in npj: Science of Learning, researchers at Carnegie Mellon University have found a way to decode the brain activity associated with individual abstract scientific concepts pertaining to matter and energy, such as fermion or dark matter.

Robert Mason, senior research associate, Reinhard Schumacher, professor of physics and Marcel Just, the D.O. Hebb University Professor of Psychology, at CMU investigated the thought processes of their fellow CMU physics faculty concerning advanced physics concepts by recording their brain activity using functional Magnetic Resonance Imaging (fMRI).

Unlike many other neuroscience studies that use brain imaging, this one was not out to find “the place in the brain” where advanced scientific concepts reside. Instead, this study’s goal was to discover how the brain organizes highly abstract scientific concepts. An encyclopedia organizes knowledge alphabetically, a library organizes it according to something like the Dewey Decimal System, but how does the brain of a physicist do it?

The study examined whether the activation patterns evoked by the different physics concepts could be grouped in terms of concept properties. One of the most novel findings was that the physicists’ brains organized the concepts into those with measureable versus immeasurable size. Here on Earth for most of us mortals, everything physical is measureable, given the right ruler, scale or radar gun. But for a physicist, some concepts like dark matter, neutrinos or the multiverse, their magnitude is not measureable. And in the physicists’ brains, the measureable versus immeasurable concepts are organized separately.

Of course, some parts of the brain organization of the physics professors resembled the organization in physics students’ brains such as concepts that had a periodic nature. Light, radio waves and gamma rays have a periodic nature but concepts like buoyancy and the multiverse do not.

But how can this interpretation of the brain activation findings be assessed? The study team found a way to generate predictions of the activation patterns of each of the concepts. But how can the activation evoked by dark matter be predicted? The team recruited an independent group of physics faculty to rate each concept on each of the hypothesized organizing dimensions on a 1-7 scale. For example, a concept like “duality” would tend to be rated as immeasureable (i.e., low on the measureable magnitude scale). A computational model then determined the relation between the ratings and activation patterns for all of the concepts except one of them and then used that relation to predict the activation of the left-out concept. The accuracy of this model was 70% on average, well above chance at 50%. This result indicates that the underlying organization is well-understood. This procedure is demonstrated for the activation associated with the concept of dark matter in the accompanying figure.

Creativity of Thought

Near the beginning of the 20^th century, post-Newtonian physicists radically advanced the understanding of space, time, matter, energy and sub-atomic particles. The new concepts arose not from their perceptual experience, but from the generative capabilities of the human brain. How was this possible?

The neurons in the human brain have a large number of computational capabilities with various characteristics, and experience determines which of those capabilities are put to use in various possible ways in combination with other brain regions to perform particular thinking tasks. For example, every healthy brain is prepared to learn the sounds of spoken language, but an infant’s experience in a particular language environment shapes which phonemes of which language are learned.

The genius of civilization has been to use these brain capabilities to develop new skills and knowledge. What makes all of this possible is the adaptability of the human brain. We can use our ancient brains to think of new concepts, which are organized along new, underlying dimensions. An example of a “new” physics dimension significant in 20^th century, post-Newtonian physics is “immeasurability” (a property of dark matter, for example) that stands in contrast to the “measurability” of classical physics concepts, (such as torque or velocity). This new dimension is present in the brains of all university physics faculty tested. The scientific advances in physics were built with the new capabilities of human brains.

Another striking finding was the large degree of commonality across physicists in how their brains represented the concepts. Even though the physicists were trained in different universities, languages and cultures, there was a similarity in brain representations. This commonality in conceptual representations arises because the brain system that automatically comes into play for processing a given type of information is the one that is inherently best suited to that processing. As an analogy, consider that the parts of one’s body that come into play to perform a given task are the best suited ones: to catch a tennis ball, a closing hand automatically comes into play, rather than a pair or knees or a mouth or an armpit. Similarly, when physicists are processing information about oscillation, the brain system that comes into play is the one that would normally process rhythmic events, such as dance movements or ripples in a pond. And that is the source of the commonality across people. It is the same brain regions in everyone that are recruited to process a given concept.

So the secret of teaching ancient brains new tricks, as the advance of civilization has repeatedly done, is to empower creative thinkers to develop new understandings and inventions, by building on or repurposing the inherent information processing capabilities of the human brain. By communicating these newly developed concepts to others, they will root themselves in the same information processing capabilities of the recipients’ brains as the original developers used. Mass communication and education can propogate the advances to entire populations. Thus the march of science, technology and civilization continue to be driven by the most powerful entity on Earth, the human brain.

The project was funded by the Office of Naval Research and the National Science Foundation.

The paper, co-authored by geology professor Ed Keller and colleagues Summer Gray, an assistant professor of environmental studies, Keith Clarke, a professor of geography, and Erica Goto, a postdoctoral scholar who completed her Ph.D. in geography, is published in the International Journal of Disaster Risk Reduction.

The work is part of an ongoing effort to understand and improve how communities prepare for future disasters. “There were a lot of problems because people didn’t know what to do,” said Keller. “We need to learn from that.”

The Montecito debris flows that occurred in January 2018 were the result of a rare confluence of two uncommonly severe events: the Thomas Fire — at that time the largest wildfire in California history — which which for weeks burned through Ventura and Santa Barbara counties; and the intense winter storm that followed, at one point dumping half an inch of rain in a five-minute period on the newly charred mountainside. Add to that combination a topography that is prone to swift floods, as rain-swollen creeks jump their banks, creating new channels.

“All of Montecito was built on these alluvial fans,” Keller said. “The whole place.”

Residents of Montecito were made aware of the possible disaster and given an evacuation order the day before the storm’s arrival, but many chose to stay.

In surveys and interviews with hundreds of respondents, the researchers sought the residents’ reasons for choosing not to evacuate. Lack of knowledge of debris flows seems to have contributed to a false sense of security.

“From the interviews, we learned that they did not know about previous debris flows in Santa Barbara County and in Montecito, and that they didn’t know what a debris flow was,” said Goto, the lead author of the study, which is likely the first paper to dive into the physical systems of and the behaviors surrounding catastrophic debris flows. “And so, they did not understand their risk.”

Unlike wildfires — regular events for Californians — debris flows of the magnitude that occurred in Montecito are exceptionally rare, with an average recurrence interval of about 1,700 years, and a 6% chance of such a catastrophic event occurring in the next 100 years, according to the paper. However, said the researchers, it is important to remember that rare events based on probability do not mean they cannot occur again at shorter time periods. Smaller debris flows are common when rains follow wildfires, Keller pointed out, but they usually don’t make it out of the mountains.

Nevertheless, the researchers said, smaller but hazardous debris flows have flowed beyond the mountain front in recent decades. Also, with climate change bringing more intense wildfire and rainstorms, hazardous debris flows may become more common.

“These big events, such as the one that happened in Montecito in 2018, are a whole different beast,” said Keller, both for the community and for the county, whose job it was to manage the evacuations. “I think (the county) did the best they could — they didn’t understand what they were dealing with, like many people,” he said.

The lack of experience with and knowledge of this type of natural hazard led to a low perception of risk in many of the respondents, who reported that they “felt safe,” and had “no idea about debris flows,” or “did not think I was at risk.” Others, many of whom recently had to leave their homes due to the still-burning Thomas Fire, cited evacuation fatigue and pets as reasons for staying.

The dominant reason for staying given by the respondents was that they were placed in the voluntary evacuation zone in the county’s evacuation map, which at the time of the event was based on Thomas Fire evacuation zones and not on the estimated movement of water, silt and boulders down a hillside. Thus, according to the paper, “many residents were told to evacuate who lived out of the debris flow hazard area, and many residents in the voluntary evacuation zones were in areas subject to debris flows (that is, along a stream corridor close to the channel).”

In the uncertainty before the storm, residents also turned to their social networks to help them decide whether to stay or go, Goto said, something that was “surprising, but also expected since residents did not understand their risk.” Lack of understanding about debris flows is also thought to be a factor behind some last-minute decisions to flee and try to outrun the 30 mile-per-hour flows, which resulted in some residents being swept up in the rush of mud and rocks.

The interviews and surveys also addressed subsequent evacuation notices in March 2018, ahead of heavy storms. The researchers wanted to see whether evacuation compliance would increase significantly after residents had been primed with the experience of the first disaster. Contrary to the research group’s expectations, evacuation compliance between the January and March orders increased slightly, but was not statistically significant, an outcome the study says could be attributed to the relative moderate to high rates of compliance (more than 60% in both cases) — and possibly also loss of confidence in the county after the tragedy of the January debris flows.

Though catastrophic debris flows are uncommon — and precisely because we’re not likely to see another one in the same area in our lifetimes — Goto, Keller and colleagues have been working to glean as much knowledge as possible about the Montecito debris flows from a variety of perspectives, including physical processes, social implications and vulnerability. The memory of the disaster should be kept alive, they say, if only to serve as a warning to present and future residents that the ground under their feet is not as stable as they might think. And with climate change increasing the intensity and frequency of severe events such as wildfires and winter rains, rare events might become more common.

According to Goto, who specializes in the combination of physical and social aspects of disaster risk reduction, residents, particularly those who are new to the area, would benefit from a long-term, onging public awareness program and educations about the risks.

Katie Stack Morgan is the Mars 2020 Deputy Project Scientist and a research scientist at NASA’s Jet Propulsion Laboratory (JPL), and will be providing an update on early results on the Mars 2020 rover mission on Sunday, 10 Oct., at the Geological Society of America’s Connects 2021 annual meeting in Portland, Oregon.

With Perseverance’s high-tech suite of on-board instruments, the scientific team has been analyzing the rocks of the crater floor, interpreted for now as igneous rocks, presumably a volcanic lava flow.

“The idea that this could be a volcanic rock was really appealing to us from a sample return perspective because igneous rocks are great for getting accurate age dates. Jezero was one of the few ancient crater lake sites on Mars that seemed to have both incredible sedimentary deposits as well as volcanic deposits that could help us construct the geologic time scale of Mars,” said Stack Morgan.

The lake system and rivers that drained into Jezero crater were likely active around 3.8-3.6 billion years ago, but the ability to directly date the age of the rocks in laboratories on Earth will provide the first definitive insight into the window of time that Mars may have been a habitable planet.

Using Perseverance’s abrasion tool — which scratches the top surface of the rock to reveal the rock and its textures — the team discovered that the crater floor seems to be composed of coarser-grained igneous minerals, and there are also a variety of salts in the rocks. Observations suggest that water caused extensive weathering and alteration of the crater floor, meaning that the rocks were subjected to water for a significant duration of time.

After using its on-board tools to analyze characteristics of the crater floor, the next phase was for Perseverance to collect a rock sample using its drill feature. However, after Perseverance completed its first attempt at drilling, the core sample tube came up empty.

“We spent a couple of days looking around the rover thinking that the core might have fallen out of the bit. Then we looked back down the drill hole thinking it might never have made it out of the hole. All these searches turned up empty. In the end we concluded that the core was pulverized during drilling,” said Stack Morgan.

The rock likely became so altered and weakened from interactions with water that the vibrations and strength from the Perseverance drill pulverized the sample.

Scientists then targeted another rock that appeared more resistant to weathering, and Perseverance was able to successfully collect two core samples — the first in its sample collection. Perseverance’s cache of samples will be part of a multi-spacecraft handoff, still in development, that will hopefully be returned to Earth in the early 2030s. From there, scientists in laboratories on Earth will date and analyze the rocks to see if there might be any signs of ancient Martian life.

“The rocks of the crater floor were not originally envisioned as the prime astrobiology target of the mission, but Mars always surprises us when we look up close. We are excited to find that even these rocks have experienced sustained interaction with water and could have been habitable for ancient martian microbes,” said Stack Morgan.

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