It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, September 02, 2021
PRISON NATION USA
High incarceration rates fuel COVID-19 spread and undermine US public safety
National study of anti-contagion policies is first worldwide to show reducing jail populations leads to community-wide public health benefits
Study shows that decarceration, along with mask mandates, school closures and nursing home restrictions, are the most important government policies for reducing COVID-19 spread
U.S. jails function as ‘infectious disease incubators’ for surrounding communities; high rates of viral transmission cause COVID-19 cases to multiply, ‘boomerang’ back to communities
Weekly turnover rate in U.S. jails is 55%, meaning infections in communities quickly spread to jails, vice versa
First study to link mass incarceration systems to pandemic vulnerability and international biosecurity
CHICAGO --- How can government slow the spread of COVID-19 in the U.S.? Look to America’s unique epidemic engines: jails and prisons in America.
Extremely high rates of incarceration in the U.S. undercut national public health and safety. The overcrowded, tight quarters in jails fuel constant risks of outbreaks. Add to that the daily movement of 420,000 guards in and out of the facilities and 30,000 newly released people who are likely to inadvertently carry the virus back to communities.
A new study from Northwestern Medicine, Toulouse School of Economics and the French National Centre for Scientific Research found the best way to address this public safety threat is through decarceration (i.e., reducing the number of people detained in jails).
“If we can immediately stop jailing people for minor alleged offenses and begin building a national decarceration program to end mass incarceration, these changes will protect us from COVID-19 now and will also benefit long-term U.S. public health and pandemic preparedness,” said first author Dr. Eric Reinhart, an anthropologist of public health and resident physician in the department of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine.
The study evaluated the association of jail decarceration and government anti-contagion policies with reductions in the spread of SARS-CoV-2 in the U.S. It will be published Sept. 2 in the journal JAMA Network Open.
It is the first study to link mass incarceration systems to pandemic vulnerability and international biosecurity (i.e., systems for protecting against disease or harmful biological agents). In a pandemic, amplification of COVID-19 spread by one country spills over into other nations such that mass incarceration in the U.S. is a threat not only to Americans but also to global public health at large.
Although many prior studies have documented that high incarceration rates are associated with harm to communitywide health, this study of 1,605 U.S. counties is the first to show that decarceration is associated with community-wide public health benefits.
U.S. jails, prisons are ‘infectious disease incubators’
The U.S. incarcerates people at seven times the average rate among peer nations such as France, Canada, Germany, England, etc., and holds almost 25% of the world’s incarcerated population. Due to crowded conditions with poor healthcare, U.S. jails and prisons have effectively become infectious disease incubators in which at least 661,000 cases of COVID-19 have been documented since the pandemic began.
Reinhart said this is due in large part to the 55% weekly turnover rate in U.S. jail populations, which means crowds of people—totaling approximately 650,000 each day, 75% of whom are awaiting trial and 25% of whom are serving short sentences for minor offenses—are being detained in cramped spaces, and then most are released back to their communities shortly thereafter. While detained, their chances of contracting SARS-Cov-2 increase dramatically, and when they return home, many unknowingly carry the virus back to their friends, family and neighbors.
“The majority of these people should never have been taken to jail in the first place,” Reinhart said. “There is no plausible public safety justification for their detention in a large proportion of cases, and a significant percentage of those jailed will never be convicted of the alleged crimes for which they were detained. Furthermore, no one––regardless of whether they have in fact committed a crime––should be subjected to the high risk of coronavirus infection imposed by the poor conditions in these facilities.
“The high rate at which people are cycled between communities and unnecessary short-term stays in jails is creating epidemiologic pumps that drive more and more infections in both jails and communities. This jail churn effectively produces epidemic machines that seed outbreaks both in and beyond jails, undermining public safety for the entire country.”
‘A natural experiment’
The COVID-19 pandemic resulted in large-scale releases of inmates, with many jails decarcerating at rates between 20-50%, Reinhart said.
“We used this exceptional historical episode during the pandemic to ask, ‘What were the consequences of this large-scale jail decarceration?’ It provided an opportunity for a natural experiment,” Reinhart said. “Pandemic-era decarceration wasn’t associated just with benefits for people who were released but also for everyone in the community. No study has ever been able to show this before, largely because we haven’t previously seen a real-world scenario with such sudden large-scale decarceration along with a well-documented means––like Covid-19 cases––to trace its implications for communities.”
The 1,605-county analysis from Reinhart and his co-author Daniel Chen of the Toulouse School of Economics and The World Bank encompassed 72% of the total U.S. population to provide one of the most fine-grained large analyses of anticontagion policies to date (jail decarceration along with 10 policies), including mask mandates, school closures, stay-at-home orders and more.
Reinhart and Chen estimated that an 80% reduction in U.S. jail populations––a level of decarceration achievable simply by pursuing alternatives to jail detention for those detained for non-violent alleged offenses––would have been associated with 2% reduction in daily COVID-19 case growth rates. This effect size was eight times larger in counties with above-median population density, including large urban areas, and was considerably larger when Reinhart and Chen considered not just changes in jail populations but also estimated jail turnover.
“Although this may sound like a small number,” Reinhart said, “because daily growth routes compound over time, even just a 2% reduction in daily case growth rates in the U.S. from the beginning of the pandemic until now would translate to the prevention of millions of cases. And, if on top of that, you factor in prison-related spread and the contribution of over 400,000 jail and prison guards to COVID-19 cases in their home communities––something we didn’t have access to data to track––then the contribution of the U.S. carceral system to overall COVID-19 cases in the U.S. has clearly been enormous,” he said.
Nursing home visitation bans were associated with the largest reduction (7.3%) in COVID-19 case growth rates of all the policies Reinhart and Chen analyzed, followed by school closures (4.3%), mask mandates (2.5%), prison visitation bans (1.2%), and stay-at-home orders (0.8%).
Reinhart suggested these results also carry policy lessons not just for immediate anticontagion measures but also for broader public investments to improve conditions in schools and nursing homes.
As COVID-19 cases are again increasing around the world in connection with the delta variant, Reinhart believes this study’s findings “contain useful evidence for informing maximally effective policymaking to protect the public,” he said.
Jail-linked disease spread and racial disparities
Reinhart and Chen’s recent related study in Proceedings of the National Academy of Sciences focused on the ways in which what they call “carceral-community epidemiology”–– how health in jails and prisons is always interconnected with health in broader communities––particularly affects U.S. communities of color. Black and Latinx neighborhoods endure the highest rates of policing and incarceration, so when jails amplify disease in communities, this especially affects these racialized groups, Reinhart said.
“Our prior research showed that this jail-community spread of coronavirus likely accounts for a substantial proportion of the racial disparities we have seen in COVID-19 cases across the U.S.,” Reinhart said. “Ultimately, this also harms all U.S. residents regardless of race, class or partisan affiliations, as disregarding the health of marginalized people inevitably causes harm––albeit unevenly––to everyone else in a society too.”
The rise and fall of Earth’s land surface over the last three million years shaped the evolution of birds and mammals, a new study has found, with new species evolving at higher rates where the land has risen most.
Researchers at the University of Cambridge have combined reconstructions of the Earth’s changing surface elevations over the past three million years with data on climate change over this timeframe, and with bird and mammal species’ locations. Their results reveal how species evolved into new ones as land elevation changed - and disentangle the effects of elevation from the effects of climate.
The study found that the effect of elevation increase is greater than that of historical climate change, and of present-day elevation and temperature, in driving the formation of new species – ‘or speciation’.
In contrast to areas where land elevation is increasing, elevation loss was not found to be an important predictor of where speciation happens. Instead, present-day temperature is a better indicator of speciation in these areas.
“Often at the tops of mountains there are many more unique species that aren’t found elsewhere. Whereas previously the formation of new species was thought to be driven by climate, we’ve found that elevation change has a greater effect at a global scale,” said Dr Andrew Tanentzap in the University of Cambridge’s Department of Plant Sciences, senior author of the paper.
As land elevation increases, temperature generally decreases and habitat complexity increases. In some cases, for example where mountains form, increasing elevation creates a barrier that prevents species moving and mixing, so populations become reproductively isolated. This is the first step towards the formation of new species.
The effect of increasing elevation on that rate of new species formation over time was more pronounced for mammals than for birds; the researchers think this is because birds can fly across barriers to find mates in other areas. Birds were affected more by present-day temperatures; in birds, variation in temperature creates differences in the timing and extent of mating, risking reproductive isolation from populations of the same species elsewhere.
Until now, most large-scale studies into the importance of topography in generating new species have only considered present-day land elevation, or elevation changes in specific mountain ranges.
“It’s surprising just how much effect historical elevation change had on generating the world’s biodiversity – it has been much more important than traditionally studied variables like temperature. The rate at which species evolved in different places on Earth is tightly linked to topography changes over millions of years,” said Dr Javier Igea in the University of Cambridge’s Department of Plant Sciences, first author of the paper.
He added: “This work highlights important arenas for evolution to play out. From a conservation perspective these are the places we might want to protect, especially given climate change. Although climate change is happening over decades, not millions of years, our study points to areas that can harbour species with greater potential to evolve.”
The researchers say that as the Earth’s surface continues to rise and fall, topography will remain an important driver of evolutionary change.
IMAGE: THE UNIVERSITY OF OTTAWA'S FACULTY OF MEDICINE HAS APPOINTED DR. HUSEIN MOLOO AS DIRECTOR OF PLANETARY HEALTH; SUCH A NEW POSITION AND PORTFOLIO BEING A FIRST NATIONWIDE.view more
CREDIT: THE UNIVERSITY OF OTTAWA
As part of uOttawa’s expanded efforts in social accountability and commitment to creating a sustainable future, the Faculty of Medicine has appointed Dr. Husein Moloo as Director of Planetary Health; such a new position and portfolio being a first nationwide.
The appointment of Dr. Moloo as the maiden Director of Planetary Health is part of the Faculty’s contribution to the University’s Transformation 2030 pledge to promote use of greener practices and activities on campus, and beyond. The appointment of Dr. Moloo – an Associate Professor of Surgery at the Faculty of Medicine – comes at a time when the World Health Organization has declared the climate crisis as the largest public health emergency.
“With the current climate crisis, we need everyone pulling in the same direction,” says Dr. Moloo, who has led Quality Improvement and Patient Safety for the Department of Surgery at the Ottawa Hospital. “There still isn’t a realization that healthcare contributes substantive amounts of greenhouse gases and strategies are needed to address this quickly. If you take healthcare as its own global entity, it would rank as the fifth highest country in terms of emissions.”
Faculty footprint
Dr. Moloo’s mandate will see him usher in initiatives and best practices across the Faculty of Medicine, with an eye to extending them to the University’s partner institutions. Initial priorities will look at decreasing the Faculty and its partner’s footprint; researching the effects of healthcare on the environment and on the impact of climate change on human health; and building an educational curriculum around it. Ottawa is committed to becoming a zero-carbon campus by 2040 and a zero-waste campus by 2050.
The impact of climate change on health is well known but greater knowledge and policy change are required to mitigate the detrimental effects.
“Environmental cost and social accountability are important focus areas, so we need to create a change in culture that looks beyond economic costs,” says Dr. Moloo, who is also a clinical investigator in epidemiology at the Ottawa Hospital Research Institute (OHRI).
“Wouldn’t it be fantastic if Planetary Health was one of the main things included longitudinally within the curriculum? We are educating future medical professionals and scientists so we need to seize this opportunity to empower our learners if progress is going to be made.”
Creating a green network
Dr. Moloo expects this announcement to create stronger ties and collaboration with other environmentally ambitious academic institutions from across Canada and around the world.
“Talk regarding planetary health is not always backed up by action but by creating this role, the Faculty of Medicine together with the University of Ottawa have solidified their intent to create change to provide sustainable impact,” says Dr. Moloo, “and I hope this will help unite the Faculty of Medicine in the fight against climate change.”
Dr. Mark Walker, Vice-Dean of Internationalization and Global Health (IGHO) at the Faculty of Medicine, has been instrumental in establishing the creation of this position, which is part of the Faculty’s 2020-2025 strategic plan. The Dean of the Faculty, Dr. Bernard Jasmin, is delighted to see this move forward as the Faculty of Medicine embraces sustainability in all its forms.
“The launch of this new initiative within the Faculty of Medicine, together with the appointment of Dr. Moloo, is not only timely but absolutely necessary,” says Dean Jasmin. “Looking at all the recent and tragic climate-related events worldwide including the fact that July 2021 was the hottest month ever recording on Earth, provides ample justification for urgently acting. Our concrete actions in this regard further highlight our vision for a healthier world and planet as well as our commitment to sustainability and social accountability.”
Geckos glide, crash-land, but don’t fall thanks to tail
Soft perching robot validates the benefit of having a fifth leg
Stuttgart – Geckos’ impressive climbing abilities give them agility rarely surpassed in nature. With their highly specialized adhesive lamellae on their feet, geckos can climb up smooth vertical surfaces with ease and even move on a ceiling hanging upside down. Their ability to run on water adds is another superpower. Now another can be added.
A scientific study published on September 2nd 2021 in Nature Communications Biology by researchers who work at the intersection between robotics and biology shows the geckos are capable of even more. In the publication titled Tails stabilize landing of gliding geckos crashing head-first into tree trunks, the authors Rob Siddall, Greg Byrnes, Robert Full and Ardian Jusufi present footage showing that geckos with no major specializations for flight are in fact capable gliders. Experiments with a gecko-inspired robot confirm the reptile’s locomotion abilities are not entirely down to its feet. The tail plays just as much a pivotal role, the team from the Max Planck Institute for Intelligent Systems in Stuttgart, Siena College in New York, and the University of California at Berkeley discovered.
In their work, the scientists begin by showing that the multi-talented lizard known as Hemidactylus platyurus is capable of gliding. In its natural habitat, it lives in trees and can jump many meters from one tree trunk to the next to avoid predators. When trees are close and the jump is short, the gecko is still accelerating so that everything between jump and landing happens at the blink of an eye. The gecko experiences an unbraked collision. Surprisingly, the gecko can cope with smashing full-on into a tree trunk.
Ardian Jusufi, who initiated the study, set up several experiments in a wildlife reserve in the rainforests of Singapore. At the Max Planck Institute for Intelligent Systems, he leads the Cyber Valley research group “Locomotion in Biorobotic and Somatic Systems”. He has spent many years investigating geckos and their many locomotion abilities. In the tree canopy, Jusufi explored a situation where reptiles both with and without a tail face the challenge of a short accelerating glide.
Placed on a platform seven meters above the ground, a tail-equipped gecko leaps down into the deep and glides to a nearby tree. High speed cameras capture the fall and show that the jumping gecko reaches 6 m/s, just over 21 km/h. Unlike a car that would be heavily dented after driving into a tree at this speed, the footage shows the gecko lands on the trunk without falling off. It moves away as if nothing happened. With tailless animals, it was quite the opposite. Geckos who had naturally lost their tails couldn’t maintain their grip after the crash and, consequently, fell off the tree trunk after landing.
As can be seen in the corresponding video (https://youtu.be/LXRAWypJBPI), the mechanism the animal applies to cushion the impact is bending its torso backward as far as 100 degrees. During the bend, the front feet lose grip. Only the rear legs remain attached. This pitch-back of the torso dissipates energy as it pushes the tail hard into the trunk. Animals that have lost tails could not dissipate sufficient energy and fell. The tail acts as a fifth leg, helping the gecko stabilize after the impact, they believed. But without a control experiment can one conclusively show that the tail has this stabilizing effect? Hence, they set off to the lab.
The scientists created a physical model of a gecko to better understand the forces the animal experiences. Their gecko-inspired robot features a soft torso, where the tail can be taken off and put back on. When the front foot hits a surface, the robot is programmed to bend its tail just like the reflex that Jusufi discovered previously in climbing geckos. The information is processed via a microcontroller on the shoulder. This signal activates the motor to pull on a tendon and hence pushes the tail into the wall to slow the head over heels pitchback.
Back in the Locomotion in Biorobotic and Somatic Systems lab, Robert Siddall and Ardian Jusufi began by catapulting a soft robotic lizard onto a wall with an embedded force-sensitive scale (the simulated tree trunk) which is lined with felt, to which the robot’s Velcro-lined feet can stick. The robot hit the force plate as abruptly as the geckos hitting the tree, tilting back its torso at a right angle to the surface. The roboticists then measured the force the front and back feet of the robot endured upon impact. The longer the tail, they discovered, the lower the force pulling the back feet away from the surface. The lower that force, the easier it is for the robot (and likely the animal) to hold on. Without a tail, however, the forces on the back feet become too high – the robot loses grip, bounces off, and falls. This experiment validated the scientists’ hypothesis that the tail is essential for the gecko to be able to stabilize itself on a vertical surface after colliding with it at high speed – findings that could make a significant contribution to robot landings and beyond.
“This field discovery on the perching behavior of geckos has important implications for our understanding of tails as multi-functional appendages that animals can rely on. Ranging from inertial to contact tails, they facilitate the most extreme transitions, such as from gliding flight to collision with a wall,” says Ardian Jusufi, the senior and corresponding author.
“One of the most dramatic transitions we can think of in multi-modal locomotion is to alight on a vertical surface from high-speed gliding flight to a standstill,” continues Ardian Jusufi.
Larger gliding specialists appear to avoid engaging in short glides, as there is not sufficient vertical drop height to reach terminal velocity, stop accelerating, and begin a dedicated landing maneuver with a stall prior to impact. Smaller animals may be able to use mechanically mediated solutions to negotiate such situations.
However, no one had ever quantified this amazing animal’s gliding behavior before. Such video material from the rainforest is hard to come by. “Our attempts to film the small, camouflaged lizard in the rainforest revealed a fall arresting response nobody thought these geckos could do and showed us their tails were entirely underestimated. Previously contact tails were thought to be used to maintain grip during rapid wall-running, while the findings presented here suggest that geckos exhibit exaptation of the behavior to improve the success of landing in the wake of their directed aerial descent,” says Jusufi.
“With the robot, we were able to measure something we could not with geckos in the field. The wall reaction forces at the impact upon landing confirmed that the tail is an essential part facilitating the landing in subcritical glides. Our soft robotic lander not only helps to make an impact in another field, but it can also help improve robot locomotion by increasing robustness and simplifying control,” explains Ardian Jusufi.
"Nature has many unexpected, elegant solutions to engineering problems - and this is wonderfully illustrated by the way geckos can use their tails to turn a head-first collision into a successful perching maneuver. Landing from flight is difficult, and we hope our findings will lead to new techniques for robot mobility – sometimes crashes are helpful," Robert Siddall describes.
Gliding flight has evolved repeatedly in the Indomalayan lowland tropical rainforest of Southeast Asia.
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A gecko bending back its torso after crash-landing
CREDIT
MPI for Intelligent Systems
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Ardian Jusufi with a soft gecko-inspired robot
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MPI for Intelligent Systems / A. Jusufi
Additional image and video material is available here:
Robert Siddall and Ardian Jusufi*, Locomotion in Biorobotic and Somatic Systems, Max-Planck-Institute for Intelligent Systems, Germany. E-mail: rob@is.mpg.de;
IMAGE: AN ASIAN FLAT-TAILED HOUSE GECKO, HEMIDACTYLUS PLATYURUS. VIDEOS OF THESE GECKOS, COMMON IN THE FORESTS OF SINGAPORE, SHOWED THAT THEIR TAILS ALLOW THEM TO RECOVER EFFECTIVELY FROM CRASH LANDINGS ON TREE TRUNKS.view more
CREDIT: ARDIAN JUSUFI
A gecko's tail is a wondrous and versatile thing.
In more than 15 years of research on geckos, scientists at the University of California, Berkeley, and, more recently, the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, have shown that geckos use their tails to maneuver in midair when gliding between trees, to right themselves when falling, to keep from falling off a tree when they lose their grip and even to propel themselves across the surface of a pond, as if walking on water.
Many of these techniques have been implemented in agile, gecko-like robots.
But Robert Full, UC Berkeley professor of integrative biology, and Ardian Jusufi, faculty member at the Max Planck Research School for Intelligent Systems and former UC Berkeley doctoral student, were blown away by a recent discovery: Geckos also use their tails to help recover when they take a header into a tree.
Those head-first crashes are probably not the geckos' preferred landing, but Jusufi documented many such hard landings in 37 glides over several field seasons in a Singapore rainforest, using high-speed video cameras to record their trajectories and wince-inducing landings. He clocked their speed upon impact at about 6 meters per second, or 21 kilometers per hour — more than 200 feet per second, or about 120 gecko body lengths per second.
"Observing the geckos from elevation in the rainforest canopy was eye-opening. Before take-off, they would move their head up-and-down, and side-to-side to view the landing target prior to jumping off, as if to estimate the travel distance," Jusufi said.
The videos show that when this gecko — the common Asian flat-tailed house gecko, Hemidactylus platyurus — collides head-on with a tree, it grabs the trunk with its clawed and padded toes so that, as its head and shoulders rebound, it has leverage to press its tail against the trunk to prevent itself from tumbling backward onto the ground and potentially ending up as someone’s dinner.
“Far from stalling, some of these lizards are still accelerating upon impact,” Jusufi said. “They crash headfirst, pitch back head over heels at an extreme angle from the vertical — they look like a bookstand sticking away from the tree — anchored only by their rear legs and tail as they dissipate the impact energy. With the fall-arresting reflex happening so fast, only slow motion video could reveal the underlying mechanism.”
This surprising behavior, and a demonstration that robots with tails that act similarly also can successfully recover from crash landings, will be reported this week in the Nature journal Communications Biology. Though this type of headfirst crash landing has not been documented previously among geckos or other gliding animals, the scientists suspect that other small, lightweight leapers — in particular, other lizards — use this as a backup when a perfect jump is impossible.
“They may have longer glides that are more equilibrium glides, and they land differently, but, for example, if they are trying to escape, they choose to do this kind of behavior, in part because size matters,” Full said, noting that the lizards measure only a couple of inches from snout to tail tip. “When you're that small, you have options that aren't solutions for big things. So, this is sort of a body-mediated solution that you don't have if you're bigger.”
Jusufi and Full note that structures similar to gecko tails could be used to help stabilize flying robots, such as drones, when they land on vertical surfaces.
According to the researchers, this unusual behavior, which they're the first to document, mathematically model and reproduce in a soft robot, is an example of how an evolutionary innovation like a tail can be used in unforeseen ways. Vertebrate tails evolved in aquatic animals, likely as a means of propulsion in the water — something Jusufi also studies and models with soft robots that undulate. But the tail turned out to be such a versatile thing that the lizard evolved various exaptations, a term for structures that were shaped by natural selection for a particular function or adaptation, but that have been used for other behaviors.
“Exaptations are structures that have been co-opted for many behaviors, no matter what that structure evolved for originally, and here's one that you wouldn't expect,” Full said. “You can see how that incredible capability of being robust can allow these exaptations.”
“Until recently tails had not received as much attention as legs or wings, but people are now realizing that we should think of these animals as five-legged, in a way — pentapedal,” Jusufi said.
Full said that as robotic engineers attempt to add more and more functions to robots, they are finding that they can’t introduce a new part for every capability. A tail is one structure that, as lizards found out, can have multiple purposes.
“As we evolve our robots and physical systems, engineers all want to do more things. And guess what? At some point, you can't optimize a robot for everything,” he said. “You have to use things for other behaviors in order to get those behaviors.”
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The Asian flat-tailed gecko would prefer a four-point landing after leaping to a tree trunk, but if it can't slow down sufficiently, it may have to crash head first into the trunk, rebounding but stabilizing itself with its tail. Researchers at the Max Planck Institute for Intelligent Systems in Germany built a soft robot with an active tail to replicate this behavior.
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Photos by Ardian Jusufi, illustration by Andre Wee
A robot catapult
In Singapore, Jusufi and his colleagues used high-speed cameras to record geckos leaping to trees that were too close to allow gliding. Even though the flat-tailed gecko is not particularly adapted to gliding — some geckos have skin flaps that are like parachutes – it has some ability to glide and thus maneuver in midair. But gliding requires reaching terminal velocity so that the lizard can maneuver in midair, and the leaps weren't long enough for that.
Unable to glide or slow themselves by stalling before landing, the geckos crashed hard, usually headfirst. When they analyzed the trajectories and mechanics of the falling geckos, the researchers found that some were still accelerating on impact. Most could not maintain a grasp on the tree with their front feet.
“Our field observations of these small, agile lizards in the rainforest revealed highly dynamic, fall-arresting responses nobody thought these geckos could execute with their tails,” Jusufi said. "Our field observations suggest they exapted tail behavior thought to be for climbing to perching after gliding flight."
The researchers modeled the behavior mathematically to confirm that what they were seeing made sense physically, but to really determine what the geckos were experiencing, they decided to build a soft robot at the Max Planck Institute that resembles a gecko and launch it with a catapult into the wall. This way, they could measure the forces actually sustained by the geckos when they crash-land, and the forces produced by the feet.
They built the tailed robot from parts made by a state-of-the art 3D printer, Carbon M2, that is specifically designed to print soft structures. The feet were outfitted with Velcro to stick upon contact, and to the tail they added a mechanism that would make it press downward when the front legs hit a surface and slip, like the gecko’s tail reflex.
Surprisingly, the tailed robot had similar success when making hard landings. In the wild, 87% of geckos with tails successfully landed on a vertical surface without falling, while tailless geckos fell more frequently. (Geckos often shed their tails to escape from predators or their rivals, and regrow them later.) Tailless robots were only able to land successfully on a vertical surface in 15% of the trials, compared to 55% of trials involving the tailed robot.
The researchers also found that, beyond a certain length, longer tails aren’t necessarily that much better than shorter tails: Robots with tails only half the length of the head and body combined were nearly as successful as those with tails equal to the snout-vent length. Short-tailed robots, however, required twice the foot force to stay attached to the tree.
Full and Jusufi continue to study the behavior of geckos in search of principles that can be applied to the design of robots — in particular, soft robots that can perch in trees and land on vertical surfaces — but also to explore the evolutionary origins of animal locomotion. One key takeaway, Full said, is that, while engineers may seek to design the optimal robot, nature never does.
“Evolution is not about optimality and perfection, but instead, it’s about sufficiency. The just-good-enough solution really plays into giving you a breadth of capabilities so that you're far more robust in challenging environments,” Full said. “Evolution looks like more like a tinkerer who never really knows what they'll produce and uses everything that's at their disposal to make something that's workable.”
“Small arboreal animals without obvious morphological adaptations for flight are increasingly being found to exhibit surprising ability for mid-air maneuvering. Soft robotic physical models can help decipher the control of such mechanically mediated solutions to landing,” Jusufi said.
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Co-authors are Rob Siddall, a postdoctoral fellow in the Locomotion in Biorobotic and Somatic Systems Group at the Max Planck Institute, and former UC Berkeley doctoral student Greg Byrnes, now an associate professor of biology at Siena College in Loudenville, New York. The work was supported by grants from the Max Planck Institute, the Cyber Valley Research Fund, the Swiss National Science Foundation and the U.S. Army.
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU
IMAGE: A GRAPHICAL REPRESENTATION OF THE NEW WHEY-PROCESSING METHOD.view more
CREDIT: GRAPHIC COURTESY XIAO SU
CHAMPAIGN, Ill. — Researchers say the high salt content of whey – the watery part of milk left behind after cheesemaking – helps make it one of the most polluting byproducts in the food processing industry. In a new study, chemists demonstrate the first electrochemical redox desalination process used in the food industry, removing and recycling up to 99% of excess salt from whey while simultaneously refining more than 98% of whey’s valuable protein content.
According to the U.S. Department of Agriculture, cheese consumption has soared in recent years, and projections estimate its continued growth. The study reports that cheese production contributes to roughly 83% of the total waste stream in the dairy industry. This environmental detriment, along with a rapidly increasing population need for sustainable food systems, inspired University of Illinois Urbana-Champaign chemical and biomolecular engineering professor Xiao Su to approach this challenge using advanced electrochemical technologies.
The desalination process introduced in this study uses up to 73% less energy and functions at 62% of the operating cost associated with conventional desalination systems, the researchers said. The findings of the study led by Illinois graduate student Nayeong Kim are published in the Chemical Engineering Journal.
“Although excess whey is wracked with several environmental waste problems, the food industry also recognizes it as a valuable nutrient source,” Su said. “By demineralizing the highly concentrated salts in whey waste in a sustainable manner, we can eliminate one of the environmental hazards associated with dairy processing while simultaneously unlocking access to the valuable protein resource found in whey waste.”
Su and his team approached this challenge by introducing a chemical redox-coupled dialysis system – a device that is not all that different from a battery cell. The method comprises two independently controllable channels for the whey waste and the electrodes, separated by a pair of ion-exchange membranes. Su said the process allows continuous desalination via a reversible redox reaction.
“Our system recovers valuable whey proteins without the risk of protein aggregation or denaturation,” Kim said. “Also, the molecular size of redox species is larger than the membrane pore size, meaning it cannot cross over the membrane to contaminate the purified proteins. I believe that the redox-mediated electrodialysis system can revolutionize the food industry by tackling coupled environmental and nutrition crises.”
During the protein purification process, positively charged sodium ions move from the feed to the redox channel and become chemically reduced at the negative electrode. The negatively charged chloride ions move to the redox channel when the reduced ions are oxidized at the positive electrode, resulting in a sustainable regeneration of the redox couple. The study reports that the redox channel can maintain its electrolyte concentration by releasing the removed ions to the feed channel, and recovered sodium chloride can be reused to season cheese, making it a net-zero waste process.
“Remarkably, the performance of protein purification and salt recovery was maintained over multiple cycles, demonstrating outstanding stability and cyclability,” Su said. “Overall, our redox-electrochemical process offers a sustainable and electrified platform for the recovery of valuable proteins from dairy production waste, with envisioned integration with renewable electricity in the future. We hope this will be the start of research into sustainable food manufacturing in general.”
To reach Xiao Su, call 217-300-0134; email x2su@illinois.edu.
The paper “Redox-mediated electrochemical desalination for waste valorization in dairy production” is available online and from the U. of I. News Bureau. DOI: 10.1016/j.cej.2021.131082.
Redox-mediated electrochemical desalination for waste valorization in dairy production
ARTICLE PUBLICATION DATE
3-Jul-2021
COI STATEMENT
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
