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Skoltech researchers were able to show that patterns that can cause neural networks to make mistakes in recognizing images are, in effect, akin to Turing patterns found all over the natural world. In the future, this result can be used to design defenses for pattern recognition systems currently vulnerable to attacks. The paper, available as an arXiv preprint, was presented at the 35th AAAI Conference on Artificial Intelligence (AAAI-21).

Deep neural networks, smart and adept at image recognition and classification as they already are, can still be vulnerable to what's called adversarial perturbations: small but peculiar details in an image that cause errors in neural network output. Some of them are universal: that is, they interfere with the neural network when placed on any input.

These perturbations can represent a significant security risk: for instance, in 2018, one team published a preprint describing a way to trick self-driving vehicles into "seeing" benign ads and logos on them as road signs. The fact that most known defenses a network can have against such an attack can be easily circumvented exacerbates this problem.

Professor Ivan Oseledets, who leads the Skoltech Computational Intelligence Lab at the Center for Computational and Data-Intensive Science and Engineering (CDISE), and his colleagues further explored a theory that connects these universal adversarial perturbations (UAPs) and classical Turing patterns, first described by the outstanding English mathematician Alan Turing as the driving mechanism behind a lot of patterns in nature, such as stripes and spots on animals.

The research started serendipitously when Oseledets and Valentin Khrulkov presented a paper on generating UAPs at the Conference on Computer Vision and Pattern Recognition in 2018. "A stranger came by and told us that this patterns look like Turing patterns. This similarity was a mystery for several years, until Skoltech master students Nurislam Tursynbek, Maria Sindeeva and PhD student Ilya Vilkoviskiy formed a team that was able to solve this puzzle. This is also a perfect example of internal collaboration at Skoltech, between the Center for Advanced Studies and Center for Data-Intensive Science and Engineering," Oseledets says.

The nature and roots of adversarial perturbations are still mysterious for researchers. "This intriguing property has a long history of cat-and-mouse games between attacks and defenses. One of the reasons why adversarial attacks are hard to defend against is lack of theory. Our work makes a step towards explaining the fascinating properties of UAPs by Turing patterns, which have solid theory behind them. This will help construct a theory of adversarial examples in the future," Oseledets notes.

There is prior research showing that natural Turing patterns - say, stripes on a fish - can fool a neural network, and the team was able to show this connection in a straightforward way and provide ways of generating new attacks. "The simplest setting to make models robust based on such patterns is to merely add them to images and train the network on perturbed images," the researcher adds.

An enzyme called MARK2 has been identified as a key stress-response switch in cells in a study by researchers at Johns Hopkins Bloomberg School of Public Health. Overactivation of this type of stress response is a possible cause of injury to brain cells in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Amyotrophic Lateral Sclerosis. The discovery will make MARK2 a focus of investigation for its possible role in these diseases, and may ultimately be a target for neurodegenerative disease treatments.

In addition to its potential relevance to neurodegenerative diseases, the finding is an advance in understanding basic cell biology.

The paper describing the discovery appears online March 11 in PLoS Biology.

The study focused on the cellular response to "proteotoxic" stress--a buildup of damaged or aggregated proteins within the main part of the cell, which is a central feature of neurodegenerative diseases. It has been known that cells respond to this type of stress by reducing their production of new proteins, and that a signaling enzyme likely mediates this response. The researchers, after ruling out other signaling enzymes, were able to show that the signaling enzyme MARK2 has this role.

"Further studies of this previously unrecognized signaling pathway should expand our understanding of protein regulation in cells and the role of this process in the development of human diseases," says Jiou Wang, PhD, a professor in the Department of Biochemistry and Molecular Biology at the Bloomberg School.

Together, Alzheimer's, ALS, and other neurodegenerative disorders afflict well over 50 million people worldwide. To date there is no disease-slowing treatment, let alone a cure, for any of them--primarily because their causes are not well understood.

One possible set of causes of neurodegenerative disorders relates to the proteotoxic stress and the response in brain cells. When this response is activated, reducing protein synthesis, it ideally minimizes the protein burden of the cell under proteotoxic stress, thereby allowing it to recover from the stress. But the long-term reduction of protein synthesis could end up starving the cell of needed proteins, injuring it, and potentially triggering cell death. In other cases, the failure of the proteotoxic stress response, rather than its overactivation, may be the problem, so that protein overload leads to cell injury or death.

To fully understand either scenario, scientists need to understand the signaling pathway that senses proteotoxic stress and switches on the proteotoxic stress response. Wang and colleagues in their new study set out to discover it.

Like others in this field, the research team already knew that the molecule at the end of this pathway that switches off protein production is a member of a broad class of signaling enzymes called kinases. They also knew in advance that there are several specific kinases that switch off protein production in the same way, but in response to other types of cellular stress, such as viral infection. The challenge in this study was to find the specific kinase that throws this switch in response to proteotoxic stress in the main part of the cell.

The researchers first identified the kinase MARK2 as one of several candidates for their inquiry by sifting through a large database, produced with prior research, of various kinases and the proteins they potentially act upon. Following up their leads with various cell-free and cell culture experiments, they were able to show that MARK2, and no other candidate kinase, can switch off the protein-making machinery in cells in response to proteotoxic stress, even when the other four known protein-shutdown kinases are absent.

Looking upstream in the signaling pathway, the team found that MARK2 is activated by another signaling kinase, PKCδ, which becomes available for its MARK2-activating role under conditions of proteotoxic stress, thus effectively acting as a proteotoxic stress sensor.

As a preliminary check on the clinical relevance of these findings, the researchers examined a mouse model of familial ALS and samples of spinal cord tissue from human ALS patients. They found evidence that this PKCδ-MARK2 pathway is highly active in these cases compared to non-ALS mice and humans.

"These findings are consistent with the idea that in ALS, for example, this PKCδ-MARK2 pathway is highly active and reducing protein production, which over the long term contributes to the disease process," Wang says.

Having clarified the basics of how this pathway works, Wang and colleagues are now planning to study it in different neurodegenerative disease models to determine whether the pathway could be targeted to treat such diseases.

"I suspect that this PKCδ-MARK2 pathway will ultimately be shown to be relevant not only in neurodegenerative disorders but in many other diseases including cancers," Wang says.

MADISON, Wis. -- Mexican wolves in the American Southwest disappeared more quickly during periods of relaxed legal protections, almost certainly succumbing to poaching, according to new research published Wednesday.

Scientists from the University of Wisconsin-Madison found that Mexican wolves were 121% more likely to disappear -- despite high levels of monitoring through radio collars -- when legal rulings permitted easier lethal and non-lethal removal of the protected wolves between 1998 and 2016. The disappearances were not due to legal removal, the researchers say, but instead were likely caused by poachers hiding evidence of their activities.

The findings suggest that consistently strong protections for endangered predators lead to reduced poaching, contrary to theories that legalizing lethal removal might reduce the motivation to poach. Instead, the scientists say, strong protections could signal both the value of endangered predators and the government's intent to enforce protections. However, exactly how government policies ultimately influence poaching activity remains unclear.

"Top predators are very important to healthy ecosystems," says Adrian Treves, a UW-Madison professor of environmental studies who oversaw the new research. "They are imperiled globally by human activities. And among human-caused mortality, poaching is the leading cause."

Treves, graduate student Naomi Louchouarn and postdoctoral researcher Francisco Santiago-Ávila published their findings March 10 in the Royal Society Open Science journal. They collaborated with David Parsons, a former U.S. Fish and Wildlife Service agent and a member the Project Coyote science advisory board, to perform the analysis.

The new report comes on the heels of the federal government's delisting of the grey wolf in November 2020 under the Endangered Species Act, which reduced protections for the carnivores.

The Mexican wolf population, a subspecies of the grey wolf, is an ideal candidate for studying the effect of government policies. Thanks to intensive reintroduction efforts, more than half of the wolves are monitored through tracking collars, which provide high-quality data on the fate of individual wolves. Policies changed multiple times over roughly two decades, creating a natural experiment that researchers can use to observe how more relaxed or stringent protections affected wolf populations.

The Treves lab asked how two distinct changes in federal protections for Mexican wolves affected the mortality of the predators in the ensuing years. From 2005 to 2009, and again from 2015 until the end of the study period in 2016, federal regulators relaxed protections for the wolves. These new policies allowed agencies to more readily remove by lethal means wolves that were deemed threats to people or livestock. Public hunting was never legalized.

The researchers found that the only cause of lost wolves that changed significantly during times of reduced protections was a category known as lost-to-follow-up, or LTF. The LTF category includes all wolves that can no longer be accounted for. LTFs can be caused by radio collar battery failures, or by wolves migrating beyond the monitored area.

Yet, the U.S. Fish and Wildlife Service found few, if any, migrants out of the recovery area and LTF events occurred significantly earlier than the expected battery life of radio collars. Those results mean that these two common causes of LTF status likely can't account for the large increase in wolves lost-to-follow-up during years of relaxed protections. The Treves group also found no evidence of changes in diseases or climate that correlated with policy changes and would increase disappearances.

Instead, they believe that the increased risk of disappearance comes from poachers who act to hide their activities by destroying radio collars and hiding carcasses. Without that evidence, however, federal agencies can't confirm a cause of death, forcing them to declare the wolves lost-to-follow-up.

Agency removal of wolves and confirmed poaching activities did not vary significantly based on policy period.

"The fact that these changes line up with these periods really tells you a lot. The wolves don't understand that policy changed, but people do," says Louchouarn. "Yet the disappearances did increase, so somebody was changing their behavior. These methods really helped us to make that connection to likely poaching."

To reduce sources of bias, the researchers developed their methods and submitted them to peer review before completing their analysis. This pre-review encourages more transparent publishing of scientific findings, regardless of the final results.

"Our findings suggest that there is no evidence for the tolerance killing hypothesis, where allowing the killing of more individuals is going to increase the tolerance for the species and therefore reduce killings," says Santiago-Ávila, who originally developed the data analysis methods to study Wisconsin's wolf population. "There is a very minimal reduction in the poaching that gets reported. But that's only because the poaching gets translated to lost individuals, which we believe represents underreported poaching."

The researchers say government agencies should reassess their assumptions that lethal removal can ultimately lead to better outcomes for the wolves. Federal policies are developed based on scientific research, so reports like this one and a previous study of Wisconsin's wolf population could help federal agencies reevaluate for the future.

"Protection is the thing that's reducing poaching," says Treves.

Fossil sites sometimes resemble a living room table on which half a dozen different jigsaw puzzles have been dumped: It is often difficult to say which bone belongs to which animal. Together with colleagues from Switzerland, researchers from the University of Bonn have now presented a method that allows a more certain answer to this question. Their results are published in the journal Palaeontologia Electronica.

Fossilized dinosaur bones are relatively rare. But if any are found, it is often in large quantities. "Many sites contain the remains of dozens of animals," explains Prof. Dr. Martin Sander from the Institute of Geosciences at the University of Bonn.

If the finder is lucky, the bones are still arranged exactly as in the living dinosaur. Some are even still connected to each other at their joints. All too often, however, they were pulled apart and dispersed by scavengers and flowing water before being embedded in the soil. "Assigning this pile of hundreds of fossilized bones to the respective individuals from which they originally came is then usually very difficult," stresses Sander, who is also a member of the transdisciplinary research area "Building Blocks of Matter and Fundamental Interactions".

This is because, for one thing, "long bones" from the arms and legs, like the thigh bone, look remarkably similar even in different species. This means that even experts are often unable to say whether a fossil thigh bone is from Diplodocus or Brachiosaurus. And even if this could be ascertained, perhaps the excavation produced several Diplodocus specimens to which it could belong.

Sander and his doctoral student Kayleigh Wiersma-Weyand have now been able to demonstrate how this can be achieved. They used dinosaur bones from the U.S. state of Wyoming as a test object. These had been excavated and partially combined into skeletons by a team from the Aathal dinosaur museum in Switzerland shortly before the turn of the millennium.

Drilling into 150 million year old bones

The Swiss researchers made their finds available to the paleontologists in Bonn for the study. Wiersma-Weyand and Sander drilled into the 150-million-year-old bones and examined the extracted core under the microscope. "This allows us to find out how old the animal in question was when it died," Wiersma-Weyand explains. For one thing, young bones are better vascularized than old ones; this means that after fossilization they have more cavities in which the blood vessels used to be. Second, bone growth proceeds in spurts. "We therefore often see characteristic annual rings, similar to what we see in trees," the researcher says.

Estimating the age often makes it possible to rule out that a bone belongs to a particular skeleton. "If the left thigh bone is ten years older than the right one, we have a problem," Sander says laconically. There were no such discrepancies in the finds examined for the study. "However, we came across bones that had previously been attributed to two different animals, but probably belong to one and the same skeleton."

The study addresses a problem that has begun to come into scientific focus in recent years: With many mounted dinosaur skeletons located in museums and collections around the world, it is still not clear whether their bones come from one or more individuals. This combination is often done deliberately during mounting, since dinosaur skeletons are rarely preserved in their entirety. Supplementing missing bones with finds from other specimens is therefore common practice and, in principle, not a big deal as long as it is recorded. More critical, however, is when researchers combine finds unknowingly and these then come from different species or animals of different ages.

When the original Diplodocus has legs that are too short

This becomes particularly relevant when the skeletons are so-called type specimens. This is because these are considered the "standard" for the corresponding species, similar to the prototype meter. But what if, for example, the original Diplodocus contains the lower legs of a younger (and thus smaller) Diplodocus specimen? "Then some of the conclusions we draw about its locomotion and lifestyle may be wrong," Sander points out. "Our research therefore also helps combat the much-cited replication crisis in science."

Together with Kayleigh Wiersma-Weyand and Master student Nico Roccazzella, he will soon be using this method to take a closer look at a famous exhibit: the "Arapahoe" skeleton, the longest skeleton of a dinosaur in Europe, which is currently on display at the Museum Koenig in Bonn.

Magnetic resonance imaging (MRI) is already widely used in medicine for diagnostic purposes. Hyperpolarized MRI is a more recent development and its research and application potential has yet to be fully explored. Researchers at Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM) have now unveiled a new technique for observing metabolic processes in the body. Their singlet-contrast MRI method employs easily-produced parahydrogen to track biochemical processes in real time. The results of their work have been published in Angewandte Chemie International Edition and chosen by the editors as a "hot paper", i.e., an important publication in a rapidly-developing and highly significant field.

Over the past decades, it has become standard practice to use MRI for medical examinations. It can be used to investigate soft tissues in the body such as the brain, intervertebral discs, and even the formation of tumors. "MRI images can show us the structure of the brain, for example, but they tell us nothing about the biomolecular processes occurring in the body, partly because of the poor sensitivity of MRI," said Dr. James Eills, first author of the study and member of the work group led by Professor Dmitry Budker at JGU and HIM.

Using hydrogen atoms instead of carbon or nitrogen isotopes

One way to significantly enhance MRI signals is hyperpolarization. This achieves significant alignment of the signal-generating nuclear spins with the help of an external magnetic field. Hyperpolarization-enhanced MRI is already being used to study biomolecular processes in the body; unfortunately, the use of carbon isotope C-13 or the nitrogen isotope N-15 is associated with certain disadvantages. "It would thus be of considerable benefit if we could use hydrogen atoms directly. Hydrogen has greater sensitivity, is more abundant, and the detection equipment is readily available," stated Eills. A drawback of hydrogen, however, is its rapid relaxation time. This means the hyperpolarized atoms revert to their original state so quickly that it is difficult to generate images.

Dr. James Eills and his colleagues tackled this problem by using a special quantum state of hydrogen nuclei called a singlet state, which derives from so-called parahydrogen. "This means we were able to overcome the drawbacks of hyperpolarized proton imaging, particularly those relating to the short relaxation time," explained Eills. While hydrogen usually has a relaxation time of a few seconds, this can be minutes in the case of singlet states. The singlet state is also non-magnetic and therefore cannot be observed. It can only be observed once the molecule is no longer symmetrical.

When fumarate is used, metabolism triggers hyperpolarization

In the study under discussion, the scientists describe their technique for singlet-contrast MRI using fumarate, a biomolecule naturally occuring as an intermediate product of metabolism. First, fumarate is produced from a precursor molecule and parahydrogen. The hyperpolarized fumarate is converted into malate by the addition of a heavy water molecule. This conversion eliminates the symmetry of the molecule, rendering it magnetic and detectable. "Then we can use the associated magnetic signals for imaging," Dr. James Eills pointed out.

Carbon-13-labelled fumarate is already a molecule that plays a significant role in hyperpolarized imaging. This work opens the possibility to perform fumarate-imaging with all the benefits of observing hydrogen rather than cabon-13. Moreover, use of parahydrogen would also be beneficial due to the fact that it can be easily produced: Hydrogen gas is simply cooled in the presence of a catalyst, which is then removed. The resulting parahydrogen can then be warmed up and remains stable in the para state for months.

"Hyperpolarized MRI is in the early stages of its development, and our contribution is an exciting new MRI variant," concluded Eills. It is possible to record images of the hyperpolarized signal at different points in time, which enables the real-time tracking of metabolic processes.

"The combination of Parahydrogen Induced Polarization with long-lived spin-states and enzymatic conversion finally breaks the door to a cost-efficient magnetic resonance imaging of fumarate and similar tumor markers in cancer metabolism," added Professor Gerd Buntkowsky, head of the Physical Chemistry of Condensed Matter group at TU Darmstadt and corresponding author of the work.

BOSTON - As COVID-19 infection rates continue to fall, Massachusetts officials are signaling it's almost time to end remote learning and send all school-aged children back to the classroom. While emerging data suggest young children and schools have not been primary drivers of the COVID-19 pandemic, evidence to guide best practices to prevent the spread of the virus in the school setting has been limited and, as a result, national and international recommendations are inconsistent.

A study led by Beth Israel Deaconess Medical Center (BIDMC) physician-researchers provides new, much-needed data about the optimal physical distancing between students for the prevention of COVID-19 in the school setting. In a retrospective, statewide cohort study, the researchers compared the rates of COVID-19 cases in students and staff in Massachusetts public schools among districts with universal mask mandates but different physical distancing requirements. The team found no substantial difference in the number of cases of COVID-19 among either students or staff in school districts that implemented a distancing policy of three feet versus six feet between students. The findings, published in the journal Clinical Infectious Diseases, suggest that lower physical distancing policies can be adopted in school settings with masking mandates without negatively impacting student or staff safety.

"Prior studies have not directly compared the impact of different physical distancing policies among students attending in-person school," said lead author Polly van den Berg, MD, a fellow in the Division of Infectious Diseases at BIDMC. "This research, which found no substantial difference in the number of cases among either students or staff in school districts that implemented a distancing policy of three versus six feet between students, is important because many school buildings have physical infrastructure that cannot accommodate six feet of distancing and bring all (or most) students back into the classroom."

Van den Berg and colleagues looked at publicly available data from 251 Massachusetts school districts, encompassing 537,336 students and 99,390 staff who attended in-person instruction during a 16-week study period from September 2020 to January 2021. Using a combination of information - including individual district infection control plans, the number of infections reported to the Commonwealth by districts, and community rates of COVID-19 from a non-partisan, not-for-profit data dashboard - the scientists found no significant difference in the rate of COVID-19 cases among students and staff in districts that mandated six feet of distancing versus in districts that mandated three feet of distancing. The scientists note that physical distancing was only one of several infection prevention measures taken by school districts.

"These data can be used to inform and update how infection control plans are implemented in school settings," added corresponding author Westyn Branch-Elliman, MD, MMSc, an infectious disease specialist at BIDMC and a clinical investigator at VA Boston Healthcare System. "It is important to remember that distancing was just one of a number of interventions adopted in the districts included in our analysis. Across the districts included in our study, there was a near-universal masking mandate, thus our study addresses the question of the effectiveness of three versus six feet of distancing among students and staff who are wearing masks."

The team's findings also showed that, in general, schools had lower overall rates of infection than their surrounding communities, lending support to the idea that in-person learning is not a major driver of the pandemic; however, district case rates were tightly linked to those of the community, particularly among staff.

"Early in the pandemic, infection control plans for schools and other settings were developed based on the best available evidence at the time -- which, early on, was limited," said Branch-Elliman, also an Assistant Professor of Medicine at Harvard Medical School. "We hope that our findings can be used to update current recommendations about distancing policy, and ultimately, to help return more students to the classroom."

Using the same principles that make polarized sunglasses possible, a team of researchers at the Arecibo Observatory in Puerto Rico have developed a technique that will help better defend against asteroids on a collision course with Earth.

A new study recently published in The Planetary Science Journal found a better way to interpret radar signals bounced off asteroids' surfaces. The data can better tell us if an asteroid is porous, fluffy or rocky, which matters because there are hundreds of near-Earth asteroids that could potentially hit the planet.

"Learning more about the physical properties of asteroids is crucial in Planetary Defense," says Dylan Hickson the lead author and a research scientist at the Arecibo Observatory in Puerto Rico. "A porous, fluffy asteroid does not pose as much of an impact threat as a dense, rocky asteroid does. With our research we can better prepare for potential asteroid impact events.

Depending on their size and composition some asteroids will burn up in the atmosphere, but others could cause catastrophic damage. Knowing how to deflect these potential threats will depend on what we know about their makeup.

Data collected from 1999-2015 with the Arecibo's main dish in Puerto Rico were used to complete the study. Arecibo is a U.S. National Science Foundation facility, which UCF manages for NSF under a cooperative agreement with Universidad Ana G. Méndez and Yang Enterprises Inc. The main dish collapsed in December, but work continues throughout the rest of the facility, and scientists continue to use previously collected data.

"When we send a radar signal with Arecibo, we know the exact polarization of the light, but when it bounces off of a surface, that can change how it's polarized," Hickson says. "If the asteroid surface was a smooth mirror, for example, it will reverse polarization 'perfectly' when the signal is reflected. With a rough and rocky surface, the light will interact with rock edges, cracks, and grains -- and reflect in a completely different polarization."

When the team analyzed Arecibo data, they broke down the polarization of the received signal into various components to decipher what surface features produced them. Is more of the surface fine-grained, smooth dust, sand-like grains or big rocks? Or is the surface full of small rocks and fine grains of dust?

Using polarimetric decomposition (polarization technique) isn't new, but it isn't 100% reliable yet. For example, scientists on NASA's OSIRIS REx mission were surprised by how rocky asteroid Bennu was when they arrived last year to begin a sample collection mission. Images taken from the spacecraft found the surface to be much more rocky than initial radar data indicated, and the team had to adjust its sample target site.

"Our results provide a methodology to extract more information about the surface properties from observations, giving us a better picture of what these mysterious surfaces look like," Hickson says. "Not only can this methodology be applied to archival data, but it can also be applied to future observations, potentially vastly increasing our understanding of the broader asteroid population."

The universe is filled with magnetic fields. Understanding how magnetic fields are generated and amplified in plasmas is essential to studying how large structures in the universe were formed and how energy is divided throughout the cosmos.

An international collaboration, co-led by researchers at the University of Rochester, the University of Oxford, and the University of Chicago, conducted experiments that captured for the first time in a laboratory setting the time history of the growth of magnetic fields by the turbulent dynamo, a physical mechanism thought to be responsible for generating and sustaining astrophysical magnetic fields. The experiments accessed conditions relevant to most plasmas in the universe and quantified the rate at which the turbulent dynamo amplifies magnetic fields, a property previously only derived from theoretical predictions and numerical simulations. The rapid amplification they found exceeds theoretical expectations and could help explain the origin of the present-day large-scale fields that are observed in galaxy clusters. Their results were published on March 8 in the Proceedings of the National Academy of Sciences.

The researchers--part of the Turbulent Dynamo (TDYNO) team--conducted their experimental research at the Omega Laser Facility at the University of Rochester's Laboratory for Laser Energetics (LLE), where they had previously demonstrated experimentally the existence of the turbulent dynamo mechanism. That breakthrough earned the team the 2019 John Dawson Award for Excellence in Plasma Physics Research from the American Physical Society.

In their most recent experiments at the Omega Laser Facilty, the researchers used laser beams whose total power is equivalent to that of 10,000 nuclear reactors. They were able to achieve conditions relevant to the hot, diffuse plasma of the intracluster medium in which the turbulent dynamo mechanism is thought to operate. The team then measured as a function of time the magnetic field amplification produced by this mechanism.

"Understanding how and at what rates magnetic fields are amplified at macroscopic scales in astrophysical turbulence is key for explaining the magnetic fields seen in galaxy clusters, the largest structures in the Universe," says Archie Bott, a postdoctoral research associate in the Department of Astrophysical Sciences at Princeton and lead author of the study. "While numerical models and theory predict fast turbulent dynamo amplification at very small scales compared to turbulent motions, it had remained uncertain as to whether the mechanism operates rapidly enough to account for dynamically significantly fields on the largest scales."

At the core of the astrophysical dynamo mechanism is turbulence. Primordial magnetic fields are generated with strengths that are considerably smaller than those seen today in galaxy clusters. Stochastic plasma motions, however, can pick up these weak "seed" fields and amplify their strengths to significantly larger values via stretching, twisting and folding of the field. The rate at which this amplification happens, the "growth rate," differs for the different spatial scales of the turbulent plasma motions: theory and simulations predict that the growth rate is large at the smallest length scales but far smaller at length scales comparable to those of the largest turbulent motions. The TDYNO experiments demonstrated that this may not be the case: turbulent dynamo--when operating in a realistic plasma--can generate large-scale magnetic fields much more rapidly than currently expected by theorists.

"Our theoretical understanding of the workings of turbulent dynamo has grown continuously for over half a century," says Gianluca Gregori, a professor of physics in the Department of Physics at the University of Oxford and the experimental lead of the project. "Our recent TDYNO laser-driven experiments were able to address for the first time how turbulent dynamo evolves in time, enabling us to experimentally measure its actual growth rate."

These experiments are part of a concerted effort by the TDYNO team to answer key questions that are debated in the turbulent dynamo literature, establishing laboratory experiments as a component in the study of turbulent magnetized plasmas. The collaboration has built an innovative experimental platform that, coupled with the power of the OMEGA laser, enables the team to probe the different plasma regimes relevant to various astrophysical systems. The experiments are designed using numerical simulations performed with the FLASH code, a publicly available simulation code that can accurately model laser-driven experiments of laboratory plasmas. FLASH is developed by the Flash Center for Computational Science, which recently moved from the University of Chicago to the University of Rochester.

"The ability to do high-fidelity, predictive modeling with FLASH, and the state-of-the art diagnostic capabilities of the Omega Laser Facility at the LLE, have put our team in a unique position to decisively advance our understanding of how cosmic magnetic fields come to be," says Petros Tzeferacos, an associate professor in the Department of Physics and Astronomy at the University of Rochester and a senior scientist at the LLE--the simulation lead of the project. Tzeferacos also serves as director of the Flash Center at Rochester.

"This work blazes a path to laboratory investigations of a variety of astrophysical processes mediated by magnetized turbulence," adds Don Lamb, the Robert A. Millikan Distinguished Service Professor Emeritus in Astronomy and Astrophysics at the University of Chicago and principal investigator of the TDYNO National Laser User's Facility (NLUF) project. "It's truly exciting to see the scientific results that the ingenuity of this team is making possible."

Optical-resolution photoacoustic microscopy (OR-PAM), a new hybrid imaging technique, allows us to listen to the sound of light and see the color of biological tissue itself. It can be used for live, multicontrast functional imaging, but the limited wavelength choice of most commercial lasers and the limitations of the existing scanning methods have meant that OR-PAM can obtain only one or two different types of contrast in a single scan. These limitations have made multicontrast functional imaging time-consuming, and it's been difficult to capture the dynamic changes of functional information in biological tissues.

To overcome these limitations, Lidai Wang and his research team at City University of Hong Kong recently developed a multiwavelength OR-PAM system based on a single laser source. As reported in Advanced Photonics, the novel system enables simultaneous multicontrast imaging of hemoglobin concentration, blood flow speed, blood oxygen saturation, and lymphatic concentration. This functional information can provide significant subcellular insights for scientists studying disease models, for instance in cancer research.

Optical-resolution photoacoustic microscopy

Based on the intrinsic absorption properties of the targeted biological tissue, photoacoustic imaging takes advantage of the fact that when tissue is targeted by a pulsed laser beam, it absorbs the light and generates instantaneous heat. That heat causes thermal expansion, which generates a mechanical ultrasonic wave, known as the photoacoustic (PA) wave. After collecting the PA wave by ultrasonic transducer and reconstructing the signal, scientists can acquire an image showing the light absorption distribution in biological tissue.

Optical-resolution photoacoustic microscopy provides high-resolution and high contrast image information for the structure, morphology, function, and metabolism of biological tissues, with prospects for broad applications in biomolecular imaging.

Five-wavelength fiber laser source

Wang's team has improved OR-PAM by developing a five-wavelength fiber laser source based on a single-wavelength nanosecond laser source. The switching time among different wavelengths happens on a submicrosecond timescale, which opens possibilities for simultaneous multifunctional OR-PAM. Wang's team validated the system stability by measuring the energy fluctuation and drift, and tested the imaging depth, as well as the lateral and axial resolution for OR-PAM imaging.

According to Wang, the system is based on the stimulated Raman scattering (SRS) effect. Basically, the pumped laser source can generate a scattered laser beam with a longer wavelength than the original incident beam through the optical fiber. When the energy of the pumped laser source exceeds a certain threshold, the generated SRS wavelength maintains high directivity, high monochromaticity, and high coherence, which makes it very suitable as the laser source of OR-PAM. The multiple scattered wavelengths can be used for multicontrast photoacoustic imaging.

Multifunctional imaging and disease modeling

Wang's team also developed a multiparameter image processing method for calculating the diameter, depth, tortuosity, and other physiological parameters in microvascular vessels, providing an image analysis basis for modeling disease. Using the five-wavelength OR-PAM, the research team further carried out multifunctional imaging of tumor development, lymphatic clearance, and brain imaging.

In their first step, they performed multifunctional microscopic imaging of small animals in vivo, including hemoglobin concentration, blood flow speed, oxygen saturation, and lymphatic concentration. They also analyzed morphological and functional differences (including diameter, blood flow, blood oxygen level, etc.) of different blood vessels in the imaging area.

Since traditional multifunctional OR-PAM requires multiple scanning and multiple laser sources to achieve such results, their work has addressed two significant problems. One is that the microenvironment of blood vessels in the tissue changes with time, so multiple long-term scanning causes inconsistencies in functional imaging. The other is the asynchrony among the different laser sources. Such fluctuations cause systematic errors in calculation. This new method can realize multifunctional imaging with a single laser source and in a single scanning, which not only greatly shortens the imaging time, but also improves the imaging accuracy.

Wang remarks, "In the future, by optimizing the scanning method, and combining with the multiwavelength OR-PAM in this work, real-time imaging of the dynamic changes for physiological parameters in some disease models can be realized."

Ann Arbor, March 11, 2021 - Black and Hispanic people experience a higher risk for COVID-19 and severe illness, influenced by factors such as discrimination, housing, and healthcare access and utilization. Now, a new study in the American Journal of Preventive Medicine, published by Elsevier, identifies specific job categories that put workers at risk because they require working in close contact with others. Some of these jobs have a disproportionately high number of Black or Hispanic workers. The findings should be used to inform workplace interventions to reduce the risk for these particularly vulnerable communities.

"About three-quarters of US workers have jobs either indoors or outdoors that involve contact with other people that is sufficiently close to put them at higher risk for COVID-19," explained co-investigators Jean M. Cox-Ganser, PhD, and Paul K. Henneberger, ScD, both of the Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA. "Our findings provide insight on where to reach the greatest number of workers who are potentially at risk for COVID-19 based on working close to others, including which occupations have larger numbers of minority workers."

Researchers used data from the Occupational Information Network (O*NET) and the Bureau of Labor Statistics (BLS) to classify the occupations of all US workers into six categories for risk of COVID-19 exposure at work: low, medium, or high proximity work indoors; and low, medium, or high proximity work outdoors. They studied the distribution of workers by occupation in the higher risk categories (medium or high proximity indoors and high proximity outdoors) and determined where Black and Hispanic workers were overrepresented.

Information on 772 detailed occupations and 144,525,054 workers was examined. Researchers found that a high proportion of US workers may be at greater risk for exposure to COVID-19 because their occupations involve either high proximity to others indoors or outdoors (25.2 percent, 36.5 million people) or medium proximity work indoors (48.0 percent, 69.6 million workers). A higher proportion of Black workers perform high proximity indoor work compared to all workers (27.5 percent vs 22.1 percent). In contrast, Hispanic workers had higher representation in outdoor work categories: 5.0 percent Hispanic vs 3.1 percent all workers in high proximity outdoor work and 7.0 percent vs 5.3 percent in medium proximity outdoor work.

Black workers were overrepresented in 103 of the 772 occupations. Eighty of those occupations were in the proximity and indoor/outdoor categories at higher risk for exposure and included 34.7 percent of all Black workers. Hispanic workers were overrepresented in 124 of the 772 occupations. Seventy-six of these occupations were in higher risk categories and included 21.5 percent of all Hispanic workers.

The authors highlighted the most populous occupations in each of the three higher risk exposure categories where Black or Hispanic workers were overrepresented. The indoor high proximity occupations for Black workers were Home Health Aides, Nursing Assistants, and Personal Care Aides, while for Hispanic workers they were Restaurant Cooks, Medical Assistants, and Dining Room/Cafeteria Attendants and Bartender Helpers. The outdoor high proximity occupations had many fewer Black than Hispanic workers. In this category large numbers of Hispanic workers were Landscaping and Groundskeeping Workers, Carpenters, and Cement Masons and Concrete Finishers. Looking at indoor medium proximity work, Laborers and Freight, Stock and Material Movers included large numbers of both Black and Hispanic workers. Additionally, large numbers of Black workers were Cashiers and Stock Clerks/Order Fillers, while large numbers of Hispanic workers were Hand Packers/Packagers and Food Preparation workers.

Prevention strategies should consider worksite conditions, and communication messages should be tailored to the languages and preferred media of the workforce.

Although there are recommendations for keeping a distance of at least six feet between people to minimize the spread of SARS-CoV-2, such social distancing may not be possible in indoor and outdoor occupations that require high physical proximity to perform work tasks.

"Efforts to control the spread of the virus that causes COVID-19 are still needed in all aspects of our lives, including at work. Becoming complacent in wearing a mask, physical distancing, and other prevention efforts during the rollout of the vaccine could have unfortunate consequences not only for ourselves, but also for our family members, co-workers, and friends," cautioned Dr. Cox-Ganser and Dr. Henneberger.

"We all have a role to play, including getting the COVID-19 vaccine when it is offered."

CHAMPAIGN, Ill. -- The chronic stress of living in neighborhoods with high rates of violence and poverty alters gene activity in immune cells, according to a new study of low-income single Black mothers on the South Side of Chicago.

The changes in stress-related gene expression reflect the body's "hunker down" response to long-term threat, a physiological strategy for lying low and considering new actions rather than launching an immediate "fight-or-flight" response. This has implications for health outcomes in communities of color and other marginalized populations, said researchers at the University of Illinois Urbana-Champaign and collaborators at the University of Kentucky and UCLA. The researchers published the study in the journal Psychoneuroendocrinology.

"The question we asked is, how does stress get under the skin to affect health and wellness? We wanted to hear the stories of low-income single Black mothers on the South Side of Chicago and really try to understand what it's like to live in neighborhoods with high levels of violence and how it affects these women," said study leader Ruby Mendenhall, an Illinois professor of African American studies and of sociology, and the assistant dean for diversity and democratization of health innovation at the Carle Illinois College of Medicine.

Mendenhall's group surveyed 68 women from high-violence neighborhoods. They shared stories, filled out stress assessments and gave blood samples.

From the women's accounts and surveys, as well as from police records of violent crime, the researchers measured levels of stress related to racism, poverty and neighborhood violence.

Then, the researchers studied how genes related to stress and immunity were expressed in white blood cells, called leukocytes, found in the participants' blood samples.

"Leukocytes are part of the immune system. They become activated to help fight disease and infection, and also respond to certain stress hormones, and that means their genes are good indicators for the effects of stress on health and well-being," said study co-author Gene Robinson, an entomology professor and the director of the Carl R. Woese Institute for Genomic Biology and interim dean of the College of Liberal Arts and Sciences at the U. of I.

When looking at genes associated with a flight-or-flight stress pathway, the researchers saw no significant differences between participants who perceived their neighborhoods as dangerous and those who did not. However, they found that women who reported greater neighborhood danger showed significantly greater activity of genes regulated by the glucocorticoid receptor - a stress-response pathway that previously has been documented in animals' hunker-down response to persistent, overwhelming threat, said study co-author Steve Cole, a professor at UCLA.

"These hunker-down responses are the body's strategy for conserving resources and persevering in the face of overwhelming adversity," Cole said. "Instead of preparing to fight or flee, the body bides its time and preserves itself for better days in the future. But it's important to get to that better future, or the hunkered-down body may not do the ongoing maintenance work needed for optimal health."

The distinction between the two stress pathways is important for planning health interventions and improving health outcomes, said study co-author Clare Rittschof, a professor at the University of Kentucky and former postdoctoral researcher in Robinson's group.

"Increased glucocorticoid activity is typically associated with aging, so it's as if these women are showing signs of accelerated aging, which is thought to be one reason that stress can lead to worse health outcomes," Rittschof said.

Next, the researchers are exploring the cultural coping mechanisms the Black women in the study community rely on in their daily lives, as well as training health care and social services providers and policymakers on ways to decrease stress, improve health outcomes, decrease disparities and foster health equity.

"These efforts must be coupled with policies broadly aimed to eliminate structural racism in our society, a big source of stress for African Americans," the authors said in a joint statement. "This is consistent with medical schools around the country declaring racism as a health crisis, including the Carle Illinois College of Medicine."

SAN ANTONIO -- Surgically opening the windpipe, or trachea, within the first seven days of the start of mechanical ventilation decreases the time patients spend on ventilators, shortens their ICU stay and lowers their risk of ventilator-associated pneumonia, according to a systematic review published Thursday (March 11) in JAMA Otolaryngology-Head & Neck Surgery.

"We analyzed the existing medical literature to unravel a question that is very pertinent to adult critical care," said senior author Alvaro Moreira, MD, MSc, of The University of Texas Health Science Center at San Antonio (UT Health San Antonio). "At what point should surgeons open the trachea in critical care patients to most benefit them?"

The surgery, called tracheotomy, is performed either in the operating room or at the bedside, depending on patient risk factors. The team analyzed 17 studies that included more than 3,000 patients. The systematic review compared early versus late tracheotomy, with "early" defined as being performed seven days or shorter after initiation of ventilation and "late" defined as eight days or longer, including patients who never required a tracheotomy.

Outcomes

Early tracheotomy was associated with improvement in three major clinical outcomes: ventilator-associated pneumonia (40% reduction in risk), ventilator-free days (1.7 additional days off the ventilator, on average) and ICU stay (6.3 days shorter time in unit, on average). Doing the procedure early did not impact patient mortality, however.

Patients receiving mechanical ventilation are intubated and breathe through a tube extending down into their windpipe. After 48 hours of intubation, patients in critical care units are at higher risk to develop ventilator-associated pneumonia, Dr. Moreira said.

A tracheostomy is placed for patient comfort, to wean the patient off sedatives and to increase the speed with which the patient can come off the ventilator.

"One of the hesitations for families is that their critically ill loved one is undergoing an intervention," Dr. Moreira said. "But if the patient were to develop pneumonia, that would increase their hospital stay and, in some patients, could be deadly.

"It's therefore a fine balance that providers and families need to consider when evaluating whether a patient is a good candidate for the intervention."

Implications for pandemic

Although no patients in the study were COVID-positive, the findings have potential translation to hospital critical care during the pandemic.

In March 2020, a committee of the American Academy of Otolaryngology-Head & Neck Surgery advised health care workers to "avoid performing tracheotomy in COVID-19 positive or suspected patients during periods of respiratory instability or heightened ventilator dependence." The committee said tracheotomy could be considered "in patients with stable pulmonary status but should not take place sooner than two to three weeks from the time of intubation and, preferably, with negative COVID-19 testing."

Since that time, studies have demonstrated that tracheotomy can be safely done in a negative pressure room, with proper personal protective equipment, sedation of the patient and frequent suctioning of the site.

"When investigators followed the health care providers for a month, they found that the clinicians did not contract COVID-19 when proper precautions were taken," Dr. Moreira said.

Different professional societies now state that COVID-19 patients should be considered like other patients. However, the timing of tracheostomy placement in this population is still up for debate.

Dr. Moreira is a professor in the Joe R. and Teresa Lozano Long School of Medicine at The University of Texas Health Science Center at San Antonio. Coauthors are from the University of Pennsylvania Perelman School of Medicine and the Long School of Medicine.

Crabs are living the meme life on social media lately. The memes joke that everything will eventually look like a crab. But it's actually based in some truth.

The crab shape has evolved so many times the evolutionary biologist L.A. Borradaile coined the term carcinization in 1916 to describe the convergent evolution process in which a crustacean evolves into a crab-like form from a non-crab-like form. Crabs are decapod crustaceans of the infraorder Brachyura and are considered "true crabs", most of which are carcinized. "False crabs" are of the infraorder Anomura. This group evolved crab-like body plans three or more times from an ancestor that was not carcinized.

In a paper published on March 11 in BioEssays, a team of researchers led by Harvard University found that the crab-like body plan evolved at least five times independently in both true crabs (Brachyura) and false crabs (Anomura). They also discovered the crab-like body plan has been lost at least seven times in a process called decarcinization.

The team, led by first author Joanna M. Wolfe, Postdoctoral Researcher, Department of Organismic and Evolutionary Biology (OEB), Harvard University, examined a composite of phylogenetic data for crabs. They synthesized morphological data from key fossil and living crab groups as well as data from behavior, natural history, functional morphology, and development all from previous studies by the authors.

Construction of comprehensive datasets, including fossil and extant species, representing all crab families is crucial to identifying the key characters that define what is a crab," said Wolfe. "This will allow us to resolve the multiple origins and losses of 'crab' body forms through time and identify the timing of origin of key evolutionary novelties and body plans."

Carcinization is characterized by a wide, flat carapace (the hard upper shell) and a folded pleon (the abdomen or tail). The pleon is largely hidden under the crab body, unlike the pleon of the lobster which is visible. In decarcinization the carapace is elongated and narrow. The pleon is not bent and is usually visible or even elongated. Decarcinization is an example of a group re-evolving a morphology that had been lost, which is thought to be a rare event in evolution.

"Biologists want to know how to "predict" if a phenotype, or morphology, would evolve in a group," said senior author Heather D. Bracken-Grissom, Associate Professor, Florida International University. "Examining crab evolution provides a macroevolutionary timescale of 250 million years ago for which, with enough phylogenetic and genomic data, we might be able to predict the morphology that would result."

Wolfe agreed, "Carcinization also allows us to compare convergent evolution in fossil morphology to that in living organisms, which is not yet commonly done."

The researchers are not completely certain but posit it is likely the common ancestor of Brachyura and Anomura was not carcinized. "This evidence suggests that indeed carcinization evolved independently in those groups," said co-author Javier Luque, Postdoctoral Researcher, OEB, Harvard University and Smithsonian Tropical Research Institute.

Wolfe is currently working with Assistant Professor Javier Ortega-Hernández, OEB, Harvard University, to test the hypothesis that carcinization can be quantitatively characterized by measuring the shapes of extant crab specimens from the Museum of Comparative Zoology, Harvard University, collections.

As experts nationwide point to a mental health crisis among teens and young adults, a pilot program teaching mindfulness and coping techniques to students at the University of Washington has helped lower stress and improve emotional well-being.

New studies by the psychology researchers who created the program find that the strategies, offered first in residence halls and later through classes and other organized campus groups, have provided participants with successful methods for coping with stress, managing their emotions and learning self-compassion.

Researchers say the results show the potential for preventive mental health services offered in an accessible, peer-group environment.

"This program is not a substitute for campus mental health services for students. But with a preventive program, our goal is to reduce general distress in college students and hopefully prevent need for increased or more intensive services," said Liliana Lengua, psychology professor and director of the Center for Child and Family Well-Being at the UW.

Recent studies of the program's rollout point to its success. Results from the program's first year, when it was offered in 2017-2018 in residence halls on the UW's Seattle campus, were published March 10 in Anxiety, Stress & Coping. Results of its second year, provided during the 2019-2020 academic year by trained university staff in campus settings such as classes and student organizations, were published Feb. 12 in Frontiers in Psychiatry. Student participants reported significant improvements in their psychological well-being that lasted three months after the sessions ended.

During the pandemic -- with millions of young people studying remotely -- the importance of teen and college student mental health has grown. According to the CDC, 1 in 4 young adults between the ages of 18 and 24 has considered suicide in the past year, while separate studies of college students in recent months have found more than 70% report serious distress.

But even before the pandemic, campuses nationwide were reporting high levels of student stress and anxiety, with college mental health directors noting need for services that far outpaced availability. Academic demands, financial pressures, social tumult and, especially among first-year students, the transition to campus life all affect student mental health.

Against this backdrop, the authors decided to come up with a short intervention at the UW that would provide real-world coping strategies in an environment that students could access easily -- without an appointment or any fee, in the casual atmosphere of a group, and where they already live, study or socialize. The program, called Be REAL, or Resilient Attitudes and Living, combined traditional cognitive behavioral coping strategies -- such as planning, positive reframing and acceptance -- with mindfulness practices focused on regulating breathing, meditation and accessing feelings of compassion, tolerance and gratitude toward oneself and others. By having staff who are already working with student in various settings offer the program, it can potentially reach more students.

"The idea behind Be REAL was to have a new model to promote student well-being and mental health. Traditional counseling systems are unlikely to keep pace with demand, so we wanted to think of a program that could be delivered more broadly by nonclinical staff members," said Robyn Long, director of community programs and training for the Center for Child and Family Well-Being.

The first year, 208 students signed up for the program across three academic quarters. Facilitators trained in mindfulness techniques led six evening sessions at four residence halls. Among the more than 80% of students who attended the majority of the sessions, results from pre- and post-surveys showed significant improvements in mindfulness and self-compassion, greater resilience and lower stress. These findings held steady in a three-month follow-up survey of participants.

Those results led to the expansion of the program to other campus settings, with associated university staff -- from the recreation department, for example, as well as those connected to student organizations -- voluntarily trained in the Be REAL program. This approach aimed to reach additional students, particularly those from underrepresented groups, in spaces they already frequent. Of the 271 students who enrolled in Be REAL programming, 116 agreed to participate in the study; more than half were students of color.

Researchers found results that were similar to the residence hall study, especially regarding stress and emotional regulation. In their comments on post-study surveys, students reported using meditation and breathing techniques to help focus or calm down, and developing habits to handle stress.

The results raised other issues that researchers are exploring further, such as whether providing the lessons in a class that students take for credit creates more of a perceived burden -- and thus, leaves less of an impact -- than sessions in which students simply choose to participate.

A new, ongoing study is examining how about 100 university staff from all three UW campuses, trained in offering the program remotely, along with still more students, respond to the techniques for improving mental health. Those results may suggest opportunities for students and staff alike to benefit from the strategies in a range of environments, on any college campus, and to possibly change a campus culture around supporting student well-being. The Center for Child and Family Well-Being is collaborating with the UW Resilience Lab to expand the program and facilitator training to staff.

"Expanding Be REAL to promote staff well-being and training is important because their work, especially with the pandemic, can be stressful," Long said. "They've even shared how the practices are shifting their interactions with children and loved ones at home. Our expansion of the program goes beyond individual well-being -- it's also about strengthening our community on campus."

In Brazil, a study conducted by researchers affiliated with the University of São Paulo (USP) and collaborators showed that deforestation in the Amazon causes an increase in the diversity of antibiotic-resistant bacteria. An article on the study, published in Soil Biology and Biochemistry, compares the microorganisms that live in the soil of native forest with those found in pasture and croplands. The researchers found a far larger number of genes considered markers of antibiotic resistance in deforested than forested areas.

“Bacteria produce substances with which to attack each other in a competition for resources that’s usual in any environment. When an area is deforested, however, several factors intensify this competition, favoring the bacteria that can resist these substances. If they reach humans, these microorganisms can become a major problem,” said Lucas William Mendes, a researcher supported by FAPESP at USP’s Center for Nuclear Energy in Agriculture (CENA) in Piracicaba, in the state of São Paulo, and last author of the article.

The study was part of a project linked to the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP) and led by Tsai Siu Mui, a professor at CENA-USP.

Antibiotic resistance is a global public health emergency, according to the World Health Organization (WHO), which says drug-resistant diseases cause some 700,000 deaths per year worldwide.

In the study, the researchers at CENA-USP, collaborating with colleagues at the Luiz de Queiroz College of Agriculture (ESALQ-USP) and scientists at the National Laboratory for Scientific Computing in Petrópolis, Rio de Janeiro State, analyzed some 800 million DNA sequences extracted from 48 soil samples collected in Pará State and northern Mato Grosso State, both of which are part of the Amazon biome.

Using bioinformatics tools, the researchers ran the DNA sequences from the samples against a genetic database and found 145 antibiotic-resistant genes that trigger 21 different molecular mechanisms. Although antibiotic-resistant bacteria are present in forest soil, these microorganisms and their resistance mechanisms are much more abundant in the soil of pasture, deforested areas, and croplands.

Deforestation microorganisms

“The process of occupation in the Amazon consists of first logging the most valuable trees and then clearing and burning all the rest to make way for crops or forage grass for cattle,” Mendes said. “Besides ash from the burned vegetation, the soil is limed to reduce the acidity and other agrochemicals are applied. The abundance of nutrients fuels bacterial proliferation and fierce competition for resources.”

Previous studies by the CENA-USP group showed that despite the reduction in forest soil microorganism diversity, the abundance of bacteria benefited plants by nutrient cycling and augmented photosynthesis, and also had positive effects on the atmosphere, including carbon fixation and consumption of methane, the second most important greenhouse gas after carbon dioxide.

In the latest study, the researchers were struck by the large quantity of bacteria that were resistant to two specific classes of antibiotics, tetracyclines and beta-lactamases. Medications with these active ingredients are widely used to treat cattle diseases and can reach the soil via feces and urine since absorption of antibiotics in cattle is low. Furthermore, the use of livestock manure as fertilizer can contribute to the spread of drug-resistant bacteria, according to the researchers.

Scientists cannot be sure that microorganisms immune to antibiotics are capable of migrating from the soil of the Amazon to food produced there, such as grain, sugarcane, and beef. “Some research assumes the transfer can occur, but to date, no studies have demonstrated it,” Mendes said. “It needs to be watched carefully because if these drug-resistant bacteria reach humans, they’ll cause a serious public health problem.”

Nor are there any immediate solutions to prevent bacteria from multiplying in cultivated soil. Management techniques that take into account other functions of microorganisms besides boosting crop yield, such as nutrient cycling and reducing species that produce methane, for example, could help mitigate the problem.

This can be done by transplanting natural soil to a cultivated area or using inoculants, microorganism-based products that perform important functions in the soil and also reduce the need for fertilizer and agrochemicals. Indeed, the market for microbiome-based agricultural products is expected to be worth more than 10 billion US dollars by 2025 (read more at: agencia.fapesp.br/34195).

In the Amazon, solutions and opportunities may be very near a pasture or plantation, in the soil of the native forest.