More stories

  • in

    Q&A: Are far-reaching fires the new normal?

    Where there’s smoke, there is fire. But with climate change, larger and longer-burning wildfires are sending smoke farther from their source, often to places that are unaccustomed to the exposure. That’s been the case this week, as smoke continues to drift south from massive wildfires in Canada, prompting warnings of hazardous air quality, and poor visibility in states across New England, the mid-Atlantic, and the Midwest.

    As wildfire season is just getting going, many may be wondering: Are the air-polluting effects of wildfires a new normal?

    MIT News spoke with Professor Colette Heald of the Department of Civil and Environmental Engineering and the Department of Earth, Atmospheric and Planetary Sciences, and Professor Noelle Selin of the Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences. Heald specializes in atmospheric chemistry and has studied the climate and health effects associated with recent wildfires, while Selin works with atmospheric models to track air pollutants around the world, which she uses to inform policy decisions on mitigating  pollution and climate change. The researchers shared some of their insights on the immediate impacts of Canada’s current wildfires and what downwind regions may expect in the coming months, as the wildfire season stretches into summer.  

    Q: What role has climate change and human activity played in the wildfires we’ve seen so far this year?

    Heald: Unusually warm and dry conditions have dramatically increased fire susceptibility in Canada this year. Human-induced climate change makes such dry and warm conditions more likely. Smoke from fires in Alberta and Nova Scotia in May, and Quebec in early June, has led to some of the worst air quality conditions measured locally in Canada. This same smoke has been transported into the United States and degraded air quality here as well. Local officials have determined that ignitions have been associated with lightning strikes, but human activity has also played a role igniting some of the fires in Alberta.

    Q: What can we expect for the coming months in terms of the pattern of wildfires and their associated air pollution across the United States?

    Heald: The Government of Canada is projecting higher-than-normal fire activity throughout the 2023 fire season. Fire susceptibility will continue to respond to changing weather conditions, and whether the U.S. is impacted will depend on the winds and how air is transported across those regions. So far, the fire season in the United States has been below average, but fire risk is expected to increase modestly through the summer, so we may see local smoke influences as well.

    Q: How has air pollution from wildfires affected human health in the U.S. this year so far?

    Selin: The pollutant of most concern in wildfire smoke is fine particulate matter (PM2.5) – fine particles in the atmosphere that can be inhaled deep into the lungs, causing health damages. Exposure to PM2.5 causes respiratory and cardiovascular damage, including heart attacks and premature deaths. It can also cause symptoms like coughing and difficulty breathing. In New England this week, people have been breathing much higher concentrations of PM2.5 than usual. People who are particularly vulnerable to the effects are likely experiencing more severe impacts, such as older people and people with underlying conditions. But PM2.5 affects everyone. While the number and impact of wildfires varies from year to year, the associated air pollution from them generally lead to tens of thousands of premature deaths in the U.S. overall annually. There is also some evidence that PM2.5 from fires could be particularly damaging to health.

    While we in New England usually have relatively lower levels of pollution, it’s important also to note that some cities around the globe experience very high PM2.5 on a regular basis, not only from wildfires, but other sources such as power plants and industry. So, while we’re feeling the effects over the past few days, we should remember the broader importance of reducing PM2.5 levels overall for human health everywhere.

    Q: While firefighters battle fires directly this wildfire season, what can we do to reduce the effects of associated air pollution? And what can we do in the long-term, to prevent or reduce wildfire impacts?

    Selin: In the short term, protecting yourself from the impacts of PM2.5 is important. Limiting time outdoors, avoiding outdoor exercise, and wearing a high-quality mask are some strategies that can minimize exposure. Air filters can help reduce the concentrations of particles in indoor air. Taking measures to avoid exposure is particularly important for vulnerable groups. It’s also important to note that these strategies aren’t equally possible for everyone (for example, people who work outside) — stressing the importance of developing new strategies to address the underlying causes of increasing wildfires.

    Over the long term, mitigating climate change is important — because warm and dry conditions lead to wildfires, warming increases fire risk. Preventing the fires that are ignited by people or human activities can help.  Another way that damages can be mitigated in the longer term is by exploring land management strategies that could help manage fire intensity. More

  • in

    Megawatt electrical motor designed by MIT engineers could help electrify aviation

    Aviation’s huge carbon footprint could shrink significantly with electrification. To date, however, only small all-electric planes have gotten off the ground. Their electric motors generate hundreds of kilowatts of power. To electrify larger, heavier jets, such as commercial airliners, megawatt-scale motors are required. These would be propelled by hybrid or turbo-electric propulsion systems where an electrical machine is coupled with a gas turbine aero-engine.

    To meet this need, a team of MIT engineers is now creating a 1-megawatt motor that could be a key stepping stone toward electrifying larger aircraft. The team has designed and tested the major components of the motor, and shown through detailed computations that the coupled components can work as a whole to generate one megawatt of power, at a weight and size competitive with current small aero-engines.

    For all-electric applications, the team envisions the motor could be paired with a source of electricity such as a battery or a fuel cell. The motor could then turn the electrical energy into mechanical work to power a plane’s propellers. The electrical machine could also be paired with a traditional turbofan jet engine to run as a hybrid propulsion system, providing electric propulsion during certain phases of a flight.

    “No matter what we use as an energy carrier — batteries, hydrogen, ammonia, or sustainable aviation fuel — independent of all that, megawatt-class motors will be a key enabler for greening aviation,” says Zoltan Spakovszky, the T. Wilson Professor in Aeronautics and the Director of the Gas Turbine Laboratory (GTL) at MIT, who leads the project.

    Spakovszky and members of his team, along with industry collaborators, will present their work at a special session of the American Institute of Aeronautics and Astronautics – Electric Aircraft Technologies Symposium (EATS) at the Aviation conference in June.

    The MIT team is composed of faculty, students, and research staff from GTL and the MIT Laboratory for Electromagnetic and Electronic Systems: Henry Andersen Yuankang Chen, Zachary Cordero, David Cuadrado,  Edward Greitzer, Charlotte Gump, James Kirtley, Jr., Jeffrey Lang, David Otten, David Perreault, and Mohammad Qasim,  along with Marc Amato of Innova-Logic LLC. The project is sponsored by Mitsubishi Heavy Industries (MHI).

    Heavy stuff

    To prevent the worst impacts from human-induced climate change, scientists have determined that global emissions of carbon dioxide must reach net zero by 2050. Meeting this target for aviation, Spakovszky says, will require “step-change achievements” in the design of unconventional aircraft, smart and flexible fuel systems, advanced materials, and safe and efficient electrified propulsion. Multiple aerospace companies are focused on electrified propulsion and the design of megawatt-scale electric machines that are powerful and light enough to propel passenger aircraft.

    “There is no silver bullet to make this happen, and the devil is in the details,” Spakovszky says. “This is hard engineering, in terms of co-optimizing individual components and making them compatible with each other while maximizing overall performance. To do this means we have to push the boundaries in materials, manufacturing, thermal management, structures and rotordynamics, and power electronics”

    Broadly speaking, an electric motor uses electromagnetic force to generate motion. Electric motors, such as those that power the fan in your laptop, use electrical energy — from a battery or power supply — to generate a magnetic field, typically through copper coils. In response, a magnet, set near the coils, then spins in the direction of the generated field and can then drive a fan or propeller.

    Electric machines have been around for over 150 years, with the understanding that, the bigger the appliance or vehicle, the larger the copper coils  and the magnetic rotor, making the machine heavier. The more power the electrical machine generates, the more heat it produces, which requires additional elements to keep the components cool — all of which can take up space and add significant weight to the system, making it challenging for airplane applications.

    “Heavy stuff doesn’t go on airplanes,” Spakovszky says. “So we had to come up with a compact, lightweight, and powerful architecture.”

    Good trajectory

    As designed, the MIT electric motor and power electronics are each about the size of a checked suitcase weighing less than an adult passenger.

    The motor’s main components are: a high-speed rotor, lined with an array of magnets with varying orientation of polarity; a compact low-loss stator that fits inside the rotor and contains an intricate array of copper windings; an advanced heat exchanger that keeps the components cool while transmitting the torque of the machine; and a distributed power electronics system, made from 30 custom-built circuit boards, that precisely change the currents running through each of the stator’s copper windings, at high frequency.

    “I believe this is the first truly co-optimized integrated design,” Spakovszky says. “Which means we did a very extensive design space exploration where all considerations from thermal management, to rotor dynamics, to power electronics and electrical machine architecture were assessed in an integrated way to find out what is the best possible combination to get the required specific power at one megawatt.”

    As a whole system, the motor is designed such that the distributed circuit boards are close coupled with the electrical machine to minimize transmission loss and to allow effective air cooling through the integrated heat exchanger.

    “This is a high-speed machine, and to keep it rotating while creating torque, the magnetic fields have to be traveling very quickly, which we can do through our circuit boards switching at high frequency,” Spakovszky says.

    To mitigate risk, the team has built and tested each of the major components individually, and shown that they can operate as designed and at conditions exceeding normal operational demands. The researchers plan to assemble the first fully working electric motor, and start testing it in the fall.

    “The electrification of aircraft has been on a steady rise,” says Phillip Ansell, director of the Center for Sustainable Aviation at the University of Illinois Urbana-Champaign, who was not involved in the project. “This group’s design uses a wonderful combination of conventional and cutting-edge methods for electric machine development, allowing it to offer both robustness and efficiency to meet the practical needs of aircraft of the future.”

    Once the MIT team can demonstrate the electric motor as a whole, they say the design could power regional aircraft and could also be a companion to conventional jet engines, to enable hybrid-electric propulsion systems. The team also envision that multiple one-megawatt motors could power multiple fans distributed along the wing on future aircraft configurations. Looking ahead, the foundations of the one-megawatt electrical machine design could potentially be scaled up to multi-megawatt motors, to power larger passenger planes.

    “I think we’re on a good trajectory,” says Spakovszky, whose group and research have focused on more than just gas turbines. “We are not electrical engineers by training, but addressing the 2050 climate grand challenge is of utmost importance; working with electrical engineering faculty, staff and students for this goal can draw on MIT’s breadth of technologies so the whole is greater than the sum of the parts. So we are reinventing ourselves in new areas. And MIT gives you the opportunity to do that.” More

  • in

    Q&A: Gabriela Sá Pessoa on Brazilian politics, human rights in the Amazon, and AI

    Gabriela Sá Pessoa is a journalist passionate about the intersection of human rights and climate change. She came to MIT from The Washington Post, where she worked from her home country of Brazil as a news researcher reporting on the Amazon, human rights violations, and environmental crimes. Before that, she held roles at two of the most influential media outlets in Brazil: Folha de S.Paulo, covering local and national politics, and UOL, where she was assigned to coronavirus coverage and later joined the investigative desk.

    Sá Pessoa was awarded the 2023 Elizabeth Neuffer Fellowship by the International Women’s Media Foundation, which supports its recipient with research opportunities at MIT and further training at The Boston Globe and The New York Times. She is currently based at the MIT Center for International Studies. Recently, she sat down to talk about her work on the Amazon, recent changes in Brazilian politics, and her experience at MIT.

    Q: One focus of your reporting is human rights and environmental issues in the Amazon. As part of your fellowship, you contributed to a recent editorial in The Boston Globe on fighting deforestation in the region. Why is reporting on this topic important?

    A: For many Brazilians, the Amazon is a remote and distant territory, and people living in other parts of the country aren’t fully aware of all of its problems and all of its potential. This is similar to the United States — like many people here, they don’t see how they could be related to the human rights violations and the destruction of the rainforest that are happening.

    But, we are all complicit in the destruction in some ways because the economic forces driving the deforestation of the rainforest all have a market, and these markets are everywhere, in Brazil and here in the U.S. I think it is part of journalism to show people in the U.S., Brazil, and elsewhere that we are part of the problem, and as part of the problem, we should be part of the solution by being aware of it, caring about it, and taking actions that are within our power.

    In the U.S., for example, voters can influence policy like the current negotiations for financial support for fighting deforestation in the Amazon. And as consumers, we can be more aware — is the beef we are consuming related to deforestation? Is the timber on our construction sites coming from the Amazon?

    Truth is, in Brazil, we have turned our backs to the Amazon for so long. It’s our duty to protect it for the sake of climate change. If we don’t take care of it, there will be serious consequences to our local climate, our local communities, and for the whole world. It’s a huge matter of human rights because our living depends on that, both locally and globally.

    Q: Before coming to MIT, you were at The Washington Post in São Paulo, where you contributed to reporting on the recent presidential election. What changes do you expect to see with the new Lula administration?

    A: To climate and environment, the first signs were positive. But the optimism did not last a semester, as politics is imposing itself. Lula is facing increasing difficulty building a majority in a conservative Congress, over which agribusiness holds tremendous power and influence. As we speak, environmental policy is under Congress’s attack. A committee in the House has just passed a ruling drowning power from the environmental minister, Marina Silva, and from the recently created National Indigenous People Ministry, led by Sonia Guajajara. Both Marina and Sonia are global ecological and human rights champions, and I wonder what the impact would be if Congress ratifies these changes. It is still unclear how it would impact the efforts to fight deforestation.

    In addition, there is an internal dispute in the government between environmentalists and those in favor of mining and big infrastructure projects. Petrobras, the state-run oil company, is trying to get authorization to research and drill offshore oil reserves in the mouth of the Amazon River. The federal environmental protection agency did a conclusive report suspending the operation, saying it is critical and threatens the region’s sensitive environment and indigenous communities. And, of course, it would be another source of greenhouse gas emissions. ​

    That said, it’s not a denialist government. I should mention the quick response from the administration to the Yanomami genocide earlier this year. In January, an independent media organization named Sumaúma reported on the deaths of over five hundred indigenous children from the Yanomami community in the Amazon over the past four years. This was a huge shock in Brazil, and the administration responded immediately. They sent task forces to the region and are now expelling the illegal miners that were bringing diseases and were ultimately responsible for these humanitarian tragedies. To be clear: It is still a problem. It’s not solved. But this is already a good example of positive action.

    Fighting deforestation in the Amazon and the Cerrado, another biome critical to climate regulation in Brazil, will not be easy. Rebuilding the environmental policy will take time, and the agencies responsible for enforcement are understaffed. In addition, environmental crime has become more sophisticated, connecting with other major criminal organizations in the country. In April, for the first time, there was a reduction in deforestation in the Amazon after two consecutive months of higher numbers. These are still preliminary data, and it is still too early to confirm whether they signal a turning point and may indicate a tendency for deforestation to decrease. On the other hand, the Cerrado registered record deforestation in April.

    There are problems everywhere in the economy and politics that Lula will have to face. In the first week of the new term, on Jan. 8, we saw an insurrection in Brasília, the country’s capital, from Bolsonaro voters who wouldn’t accept the election results. The events resembled what Americans saw in the Capitol attacks in 2021. We also seem to have imported problems from the United States, like mass killings in schools. We never used to have them in Brazil, but we are seeing them now. I’m curious to see how the country will address those problems and if the U.S. can also inspire solutions to that. That’s something I’m thinking about, being here: Are there solutions here? What are they?

    Q: What have you learned so far from MIT and your fellowship?

    A: It’s hard to put everything into words! I’m mostly taking courses and attending lectures on pressing issues to humanity, like existential threats such as climate change, artificial intelligence, biosecurity, and more.

    I’m learning about all these issues, but also, as a journalist, I think that I’m learning more about how I can incorporate the scientific approach into my work; for example, being more pro-positive. I am already a rigorous journalist, but I am thinking about how I can be more rigorous and more transparent about my methods. Being in the academic and scientific environment is inspiring that way.

    I am also learning a lot about how to cover scientific topics and thinking about how technology can offer us solutions (and problems). I’m learning so much that I think I will need some time to digest and fully understand what this period means for me!

    Q: You mentioned artificial intelligence. Would you like to weigh in on this subject and what you have been learning?

    A: It has been a particularly good semester to be at MIT. Generative artificial intelligence, which became more popular after ChatGPT, has been a topic of intense discussion this semester, and I was able to attend many classes, seminars, and events about AI here, especially from a policy perspective.

    Algorithms have influenced the economy, society, and public health for many years. It has had great outcomes, but also injustice. Popular systems like ChatGPT have made this technology incredibly popular and accessible, even for those with no computer knowledge. This is scary and, at the same time, very exciting. Here, I learned that we need guardrails for artificial intelligence, just like other technologies. Think of the pharmaceutical or automobile industries, which have to meet safety criteria before putting a new product on the market. But with artificial intelligence, it’s going to be different; supply chains are very complex and sometimes not very transparent, and the speed at which new resources develop is so fast that it challenges the policymaker’s ability to respond.

    Artificial intelligence is changing the world radically. It’s exciting to have the privilege of being here and seeing these discussions take place. After all, I have a future to report on. At least, I hope so!

    Q: What are you working on going forward?

    A: After MIT, I am going to New York, where I’ll be working with The New York Times in their internship program. I’m really excited about that because it will be a different pace from MIT. I am also doing research on carbon credit markets and hope to continue that project, either in a reporting or academic environment. 

    Honestly, I feel inspired to keep studying. I would love to spend more time here at MIT. I would love to do a master’s or join any program here. I’m going to work on coming back to academia because I think that I need to learn more from the academic environment. I hope that it’s at MIT because honestly, it’s the most exciting environment that I’ve ever been in, with all the people here from different fields and different backgrounds. I’m not a scientist, but it’s inspiring to be with them, and if there’s a way that I could contribute to their work in a way that they’re contributing to my work, I’ll be thrilled to spend more time here. More

  • in

    River erosion can shape fish evolution, study suggests

    If we could rewind the tape of species evolution around the world and play it forward over hundreds of millions of years to the present day, we would see biodiversity clustering around regions of tectonic turmoil. Tectonically active regions such as the Himalayan and Andean mountains are especially rich in flora and fauna due to their shifting landscapes, which act to divide and diversify species over time.

    But biodiversity can also flourish in some geologically quieter regions, where tectonics hasn’t shaken up the land for millennia. The Appalachian Mountains are a prime example: The range has not seen much tectonic activity in hundreds of millions of years, and yet the region is a notable hotspot of freshwater biodiversity.

    Now, an MIT study identifies a geological process that may shape the diversity of species in tectonically inactive regions. In a paper appearing today in Science, the researchers report that river erosion can be a driver of biodiversity in these older, quieter environments.

    They make their case in the southern Appalachians, and specifically the Tennessee River Basin, a region known for its huge diversity of freshwater fishes. The team found that as rivers eroded through different rock types in the region, the changing landscape pushed a species of fish known as the greenfin darter into different tributaries of the river network. Over time, these separated populations developed into their own distinct lineages.

    The team speculates that erosion likely drove the greenfin darter to diversify. Although the separated populations appear outwardly similar, with the greenfin darter’s characteristic green-tinged fins, they differ substantially in their genetic makeup. For now, the separated populations are classified as one single species. 

    “Give this process of erosion more time, and I think these separate lineages will become different species,” says Maya Stokes PhD ’21, who carried out part of the work as a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

    The greenfin darter may not be the only species to diversify as a consequence of river erosion. The researchers suspect that erosion may have driven many other species to diversify throughout the basin, and possibly other tectonically inactive regions around the world.

    “If we can understand the geologic factors that contribute to biodiversity, we can do a better job of conserving it,” says Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric, and Planetary Sciences at MIT.

    The study’s co-authors include collaborators at Yale University, Colorado State University, the University of Tennessee, the University of Massachusetts at Amherst, and the Tennessee Valley Authority (TVA). Stokes is currently an assistant professor at Florida State University.

    Fish in trees

    The new study grew out of Stokes’ PhD work at MIT, where she and Perron were exploring connections between geomorphology (the study of how landscapes evolve) and biology. They came across work at Yale by Thomas Near, who studies lineages of North American freshwater fishes. Near uses DNA sequence data collected from freshwater fishes across various regions of North America to show how and when certain species evolved and diverged in relation to each other.

    Near brought a curious observation to the team: a habitat distribution map of the greenfin darter showing that the fish was found in the Tennessee River Basin — but only in the southern half. What’s more, Near had mitochondrial DNA sequence data showing that the fish’s populations appeared to be different in their genetic makeup depending on the tributary in which they were found.

    To investigate the reasons for this pattern, Stokes gathered greenfin darter tissue samples from Near’s extensive collection at Yale, as well as from the field with help from TVA colleagues. She then analyzed DNA sequences from across the entire genome, and compared the genes of each individual fish to every other fish in the dataset. The team then created a phylogenetic tree of the greenfin darter, based on the genetic similarity between fish.

    From this tree, they observed that fish within a tributary were more related to each other than to fish in other tributaries. What’s more, fish within neighboring tributaries were more similar to each other than fish from more distant tributaries.

    “Our question was, could there have been a geological mechanism that, over time, took this single species, and splintered it into different, genetically distinct groups?” Perron says.

    A changing landscape

    Stokes and Perron started to observe a “tight correlation” between greenfin darter habitats and the type of rock where they are found. In particular, much of the southern half of the Tennessee River Basin, where the species abounds, is made of metamorphic rock, whereas the northern half consists of sedimentary rock, where the fish are not found.

    They also observed that the rivers running through metamorphic rock are steeper and more narrow, which generally creates more turbulence, a characteristic greenfin darters seem to prefer. The team wondered: Could the distribution of greenfin darter habitat have been shaped by a changing landscape of rock type, as rivers eroded into the land over time?

    To check this idea, the researchers developed a model to simulate how a landscape evolves as rivers erode through various rock types. They fed the model information about the rock types in the Tennessee River Basin today, then ran the simulation back to see how the same region may have looked millions of years ago, when more metamorphic rock was exposed.

    They then ran the model forward and observed how the exposure of metamorphic rock shrank over time. They took special note of where and when connections between tributaries crossed into non-metamorphic rock, blocking fish from passing between those tributaries. They drew up a simple timeline of these blocking events and compared this to the phylogenetic tree of diverging greenfin darters. The two were remarkably similar: The fish seemed to form separate lineages in the same order as when their respective tributaries became separated from the others.

    “It means it’s plausible that erosion through different rock layers caused isolation between different populations of the greenfin darter and caused lineages to diversify,” Stokes says.

    “This study is highly compelling because it reveals a much more subtle but powerful mechanism for speciation in passive margins,” says Josh Roering, professor of Earth sciences at the University of Oregon, who was not involved in the study. “Stokes and Perron have revealed some of the intimate connections between aquatic species and geology that may be much more common than we realize.”

    This research was supported, in part, by the mTerra Catalyst Fund and the U.S. National Science Foundation through the AGeS Geochronology Program and the Graduate Research Fellowship Program. While at MIT, Stokes received support through the Martin Fellowship for Sustainability and the Hugh Hampton Young Fellowship. More

  • in

    Civil discourse project to launch at MIT

    A new project on civil discourse aims to promote open and civil discussion of difficult topics on the MIT campus.

    The project, which will launch this fall, includes a speaker series and curricular activities in MIT’s Concourse program for first-year students. MIT philosophers Alex Byrne and Brad Skow from the Department of Linguistics and Philosophy lead the project, in close coordination with Anne McCants, professor of history and director of Concourse, and Linda Rabieh, a Concourse lecturer. 

    The Arthur Vining Davis Foundations provided a substantial grant to help fund the project. Promoting civil discourse on college campuses is an area of focus for AVDF — they sponsor related projects at many schools, including Duke University and Davidson College.

    The first event in the speaker series is planned for the evening of Oct. 24, on the question of how we should respond to climate change. The two speakers are Professor Steven Koonin (New York University, ex-provost of Caltech, and an MIT alum) and MIT Professor Kerry Emanuel from the Department of Earth, Atmospheric, and Planetary Sciences. Eight such events are planned over two years. Each will feature speakers discussing difficult or controversial topics, and will aim to model civil debate and dialogue involving experts from inside and outside the MIT community. 

    Byrne and Skow said that the project is meant to counterbalance a growing unwillingness to listen to others or to tolerate the expression of certain ideas. But the goal, says Byrne, “is not to platform heterodox views for their own sake, or to needlessly provoke. Rather, we want to platform collegial, informed conversations on important matters about which there is reasonable disagreement.” 

    Faculty at MIT voted last fall to adopt a statement on free expression, following a report written by an MIT working group. The project organizers want to build on that vote and the report. “The free expression statement says that discussion of controversial topics should not be prohibited or punished,” Skow says, “but the longer working-group report goes farther, urging MIT to promote free expression. This project is an attempt to do that — to show that open discussion and open inquiry are valuable.” 

    “It has the potential to generate lively, constructive, respectful discussion on campus and to show by example both that controversial views are not suppressed at MIT and that we learn by engaging with them openly,” says Kieran Setiya, the head of MIT Philosophy. Agustín Rayo, dean of the School of Humanities and Social Sciences, thinks that the project can “play a critical role in demonstrating — to faculty, students, staff, alumni, and friends — the Institute’s commitment to free speech and civil discourse.”

    Apart from climate change, topics for the first series of events include feminism and progress (Nov. 9, with Mary Harrington, author of “Feminism against Progress”), and Covid public health policy (Feb. 26, with Vinay Prasad, professor of epidemiology and biostatistics at the University of California at San Francisco). Organizers say they hope the speaker series becomes a permanent part of MIT’s intellectual life after the grant period. To amplify the work to an audience beyond MIT, the project organizers have partnered with the Johns Hopkins University political scientist Yascha Mounk and his team at Persuasion to produce podcast episodes around the speaker events. They will air as special episodes of Mounk’s podcast “The Good Fight.” 

    The Concourse component of the project will take advantage of the small learning community setting to develop the tools and experience for productive disagreement. 

    “The core mission of Concourse depends on both the principle of free expression and the practice of civil discourse,” says McCants, “making it a natural springboard for promoting both across the intellectual culture of MIT.”  

    Concourse will experiment with, among other things, seminars discussing the history and practice of freedom of expression, roundtable discussions, and student-led debates. Braver Angels, an organization with the mission of reducing political polarization, is another partner, along with Persuasion. 

    “Our goal,” says Rabieh, “is to facilitate, in collaboration with Braver Angels, the probing, intense, and often difficult conversations that lie at the heart of the Concourse program and that are the hallmark of education.” More

  • in

    Exploring the links between diet and cancer

    Every three to five days, all of the cells lining the human intestine are replaced. That constant replenishment of cells helps the intestinal lining withstand the damage caused by food passing through the digestive tract.

    This rapid turnover of cells relies on intestinal stem cells, which give rise to all of the other types of cells found in the intestine. Recent research has shown that those stem cells are heavily influenced by diet, which can help keep them healthy or stimulate them to become cancerous.

    “Low-calorie diets such as fasting and caloric restriction can have antiaging effects and antitumor effects, and we want to understand why that is. On the other hand, diets that lead to obesity can promote diseases of aging, such as cancer,” says Omer Yilmaz, the Eisen and Chang Career Development Associate Professor of Biology at MIT.

    For the past decade, Yilmaz has been studying how different diets and environmental conditions affect intestinal stem cells, and how those factors can increase the risk of cancer and other diseases. This work could help researchers develop new ways to improve gastrointestinal health, either through dietary interventions or drugs that mimic the beneficial effects of certain diets, he says. 

    “Our findings have raised the possibility that fasting interventions, or small molecules that mimic the effects of fasting, might have a role in improving intestinal regeneration,” says Yilmaz, who is also a member of MIT’s Koch Institute for Integrative Cancer Research.

    A clinical approach

    Yilmaz’s interest in disease and medicine arose at an early age. His father practiced internal medicine, and Yilmaz spent a great deal of time at his father’s office after school, or tagging along at the hospital where his father saw patients.

    “I was very interested in medicines and how medicines were used to treat diseases,” Yilmaz recalls. “He’d ask me questions, and many times I wouldn’t know the answer, but he would encourage me to figure out the answers to his questions. That really stimulated my interest in biology and in wanting to become a doctor.”

    Knowing that he wanted to go into medicine, Yilmaz applied and was accepted to an eight-year, combined bachelor’s and MD program at the University of Michigan. As an undergraduate, this gave him the freedom to explore areas of interest without worrying about applying to medical school. While majoring in biochemistry and physics, he did undergraduate research in the field of protein folding.

    During his first year of medical school, Yilmaz realized that he missed doing research, so he decided to apply to the MD/PhD program at the University of Michigan. For his PhD research, he studied blood-forming stem cells and identified new markers that allowed such cells to be more easily isolated from the bone marrow.

    “This was important because there’s a lot of interest in understanding what makes a stem cell a stem cell, and how much of it is an internal program versus signals from the microenvironment,” Yilmaz says.

    After finishing his PhD and MD, he thought about going straight into research and skipping a medical residency, but ended up doing a residency in pathology at Massachusetts General Hospital. During that time, he decided to switch his research focus from blood-forming stem cells to stem cells found in the gastrointestinal tract.

    “The GI tract seemed very interesting because in contrast to the bone marrow, we knew very little about the identity of GI stem cells,” Yilmaz says. “I knew that once GI stem cells were identified, there’d be a lot of interesting questions about how they respond to diet and how they respond to other environmental stimuli.”

    Dietary questions

    To delve into those questions, Yilmaz did postdoctoral research at the Whitehead Institute, where he began investigating the connections between stem cells, metabolism, diet, and cancer.

    Because intestinal stem cells are so long-lived, they are more likely to accumulate genetic mutations that make them susceptible to becoming cancerous. At the Whitehead Institute, Yilmaz began studying how different diets might influence this vulnerability to cancer, a topic that he carried into his lab at MIT when he joined the faculty in 2014.

    One question his lab has been exploring is why low-calorie diets often have protective effects, including a boost in longevity — a phenomenon that has been seen in many studies in animals and humans.

    In a 2018 study, his lab found that a 24-hour fast dramatically improves stem cells’ ability to regenerate. This effect was seen in both young and aged mice, suggesting that even in old age, fasting or drugs that mimic the effects of fasting could have a beneficial effect.

    On the flip side, Yilmaz is also interested in why a high-fat diet appears to promote the development of cancer, especially colorectal cancer. In a 2016 study, he found that when mice consume a high-fat diet, it triggers a significant increase in the number of intestinal stem cells. Also, some non-stem-cell populations begin to resemble stem cells in their behavior. “The upshot of these changes is that both stem cells and non-stem-cells can give rise to tumors in a high-fat diet state,” Yilmaz says.

    To help with these studies, Yilmaz’s lab has developed a way to use mouse or human intestinal stem cells to generate miniature intestines or colons in cell culture. These “organoids” can then be exposed to different nutrients in a very controlled setting, allowing researchers to analyze how different diets affect the system.

    Recently, his lab adapted the system to allow them to expand their studies to include the role of immune cells, fibroblasts, and other supportive cells found in the microenvironment of stem cells. “It would be remiss of us to focus on just one cell type,” Yilmaz says. “We’re looking at how these different dietary interventions impact the entire stem cell neighborhood.”

    While Yilmaz spends most of his time running his lab at MIT, he also devotes six to eight weeks per year to his work at MGH, where he is an associate pathologist focusing on gastrointestinal pathology.

    “I enjoy my clinical work, and it always reminds me about the importance of the research we do,” he says. “Seeing colon cancer and other GI cancers under the microscope, and seeing their complexity, reminds me of the importance of our mission to figure out how we can prevent these cancers from forming.” More

  • in

    3 Questions: Can disused croplands help mitigate climate change?

    As the world struggles to meet internationally agreed targets for reducing greenhouse gas emissions, methods of removing carbon dioxide such as reforestation of cleared areas have become an increasingly important strategy. But little attention has been paid to the potential for abandoned or marginal croplands to be restored to natural vegetation as an additional carbon sink, say MIT assistant professor of civil and environmental engineering César Terrer, recent visiting MIT doctoral student Stephen M. Bell, and six others, in a recent open-access paper in the journal Nature Communications. Here, Terrer and Bell explain the potential use of these “post-agricultural” lands to help in the fight against damaging climate change.

    Q: How significant is the potential of unused agricultural lands as a carbon sink to help mitigate climate change?

    Bell: We know of these huge instances of land abandonment and post-agricultural succession throughout history, like following the collapse of major cities from ancient Mesopotamia to the Mayans. And when the Europeans arrived in the Americas in the 15th century, so many people died and so much forest grew back on abandoned farmland that it helped cool the entire planet and was potentially a driver of the coldest part of the so-called “Little Ice Age” period.

    Today, we have abandoned farmland all over the Mediterranean region, where I did my PhD field work. As young people left rural areas for the cities throughout the 20th century, farmers couldn’t pass on their land to anyone, and the land succeeded back into shrub lands and forests. The biggest recent example of abandonment is for sure the collapse of the Soviet Union, where an estimated 60 million hectares of forest regrew when support for collective farming stopped, resulting in one of the largest carbon sinks ever attributed to a single event.

    So, when we look back at the past, we know there’s potential. Of course, these are huge events, and no one is proposing to replicate anything like that. We need to use land for multiple purposes, but looking back at these big examples, we know there is potential for abandoned or restored agricultural land to be carbon sinks. And so that tells us to dig deeper into this question and get a better idea of realistic scenarios, a better understanding of the climate change mitigation potential of agricultural cessation in the most strategic places.

    Terrer: More than 115 billion tons of carbon have been lost from soils due to agricultural practices that disturb soil integrity — such as tilling, monoculture farming, removing crop residue, excessive use of fertilizers and pesticides, and over-grazing. To put this into perspective, the amount of carbon lost is equivalent to the total CO2 emissions ever produced in the United States.

    Our current research synthesizes field data from thousands of experiments, aiming to understand the factors that influence soil carbon accrual in abandoned croplands transitioning back to forests or natural grasslands. We’re working to quantify the potential for carbon sequestration in these soils over 30-, 50-, and 100-year time frames and mapping the areas with the greatest potential for carbon storage. This includes both increases in soil carbon and in vegetation biomass.

    Q: What are some of the key uncertainties in evaluating this potential for unused cropland to serve as a carbon sink, and how could those uncertainties be addressed?

    Bell: We use this word uncertainties in two ways. Specifically, the longevity of potential recarbonization, and the intensity of the potential recarbonization. Those are two factors, two aspects that we need to quantify to reduce our uncertainty.

    So, how long will the land recarbonize, regardless of the intensity? If the carbon level is going up, that’s good. If there’s more carbon increasing in the soil, we know that it came from somewhere, it came from the atmosphere. But how long does that happen? We know soil can get saturated. It can reach its carbon capacity limit, it won’t continue to increase the carbon stock, and the recarbonization curve will flatten out. When does that happen? Is it after a hundred years? Is it after 20 years?

    But the world’s soils are very diverse and complex, so what might be true in one place is not true in another place. It may take a longer time to reach saturation for more fertile soils in the Midwest U.S. than less fertile soils in the Southwest, for example. Alternatively, sometimes soils in drier areas like in the Southwest may never reach true saturation if they are degraded and have stalled recovery following abandonment.

    The second uncertainty is intensity: How high on the y-axis on the chart of recarbonization does saturation occur? With the analogy comparing U.S. soils, you might have a relatively huge carbon increase on an abandoned farm in the Southwest, but because the soil is not very carbon-rich it’s not a large increase in absolute terms. In the Midwest, there might only be a small relative increase, but that increase could be much more in total than in the Southwest. These are just nuances to keep in mind as we look at this at the global scale.

    These nuances are essentially uncertainties. Soil carbon responses to agricultural land abandonment is complicated, and unfortunately it hasn’t been studied in much detail so far. We need to reduce those uncertainties to get a better understanding of the recarbonization potential. This is easier said than done because not only do we have these temporal data uncertainties, but we also have spatial uncertainties. We don’t have very good maps of past and present post-agricultural landscapes.

    Q: Can this potential use of post-agricultural lands be implemented without putting global food supplies at risk? How can these needs be balanced?

    Terrer: As to whether utilizing post-agricultural lands for carbon sequestration can be implemented without jeopardizing global food supplies, and how to balance these needs, our recent research provides valuable insights.

    The challenge, of course, lies in balancing cropland restoration for climate mitigation with food security for a growing global population. Abandoned croplands represent an opportunity for carbon sequestration without impacting active agricultural lands. However, the available area of abandoned croplands is insufficient to make a substantial impact on climate mitigation on its own.

    Thus, our proposal also emphasizes the importance of closing yield gaps, which involves increasing crop production per hectare to its theoretical limits. This would enable us to maintain or even increase global crop yields using only a fraction of the currently cultivated area, allowing the remaining land to be dedicated to climate mitigation efforts. By pursuing this strategy, we estimate that over half of the amount of soil carbon lost so far due to agriculture could be recovered, while ensuring food security for the world’s population. More

  • in

    J-WAFS announces 2023 seed grant recipients

    Today, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) announced its ninth round of seed grants to support innovative research projects at MIT. The grants are designed to fund research efforts that tackle challenges related to water and food for human use, with the ultimate goal of creating meaningful impact as the world population continues to grow and the planet undergoes significant climate and environmental changes.Ten new projects led by 15 researchers from seven different departments will be supported this year. The projects address a range of challenges by employing advanced materials, technology innovations, and new approaches to resource management. The new projects aim to remove harmful chemicals from water sources, develop monitoring and other systems to help manage various aquaculture industries, optimize water purification materials, and more.“The seed grant program is J-WAFS’ flagship grant initiative,” says J-WAFS executive director Renee J. Robins. “The funding is intended to spur groundbreaking MIT research addressing complex issues that are challenging our water and food systems. The 10 projects selected this year show great promise, and we look forward to the progress and accomplishments these talented researchers will make,” she adds.The 2023 J-WAFS seed grant researchers and their projects are:Sara Beery, an assistant professor in the Department of Electrical Engineering and Computer Science (EECS), is building the first completely automated system to estimate the size of salmon populations in the Pacific Northwest (PNW).Salmon are a keystone species in the PNW, feeding human populations for the last 7,500 years at least. However, overfishing, habitat loss, and climate change threaten extinction of salmon populations across the region. Accurate salmon counts during their seasonal migration to their natal river to spawn are essential for fisheries’ regulation and management but are limited by human capacity. Fish population monitoring is a widespread challenge in the United States and worldwide. Beery and her team are working to build a system that will provide a detailed picture of the state of salmon populations in unprecedented, spatial, and temporal resolution by combining sonar sensors and computer vision and machine learning (CVML) techniques. The sonar will capture individual fish as they swim upstream and CVML will train accurate algorithms to interpret the sonar video for detecting, tracking, and counting fish automatically while adapting to changing river conditions and fish densities.Another aquaculture project is being led by Michael Triantafyllou, the Henry L. and Grace Doherty Professor in Ocean Science and Engineering in the Department of Mechanical Engineering, and Robert Vincent, the assistant director at MIT’s Sea Grant Program. They are working with Otto Cordero, an associate professor in the Department of Civil and Environmental Engineering, to control harmful bacteria blooms in aquaculture algae feed production.

    Aquaculture in the United States represents a $1.5 billion industry annually and helps support 1.7 million jobs, yet many American hatcheries are not able to keep up with demand. One barrier to aquaculture production is the high degree of variability in survival rates, most likely caused by a poorly controlled microbiome that leads to bacterial infections and sub-optimal feed efficiency. Triantafyllou, Vincent, and Cordero plan to monitor the microbiome composition of a shellfish hatchery in order to identify possible causing agents of mortality, as well as beneficial microbes. They hope to pair microbe data with detail phenotypic information about the animal population to generate rapid diagnostic tests and explore the potential for microbiome therapies to protect larvae and prevent future outbreaks. The researchers plan to transfer their findings and technology to the local and regional aquaculture community to ensure healthy aquaculture production that will support the expansion of the U.S. aquaculture industry.

    David Des Marais is the Cecil and Ida Green Career Development Professor in the Department of Civil and Environmental Engineering. His 2023 J-WAFS project seeks to understand plant growth responses to elevated carbon dioxide (CO2) in the atmosphere, in the hopes of identifying breeding strategies that maximize crop yield under future CO2 scenarios.Today’s crop plants experience higher atmospheric CO2 than 20 or 30 years ago. Crops such as wheat, oat, barley, and rice typically increase their growth rate and biomass when grown at experimentally elevated atmospheric CO2. This is known as the so-called “CO2 fertilization effect.” However, not all plant species respond to rising atmospheric CO2 with increased growth, and for the ones that do, increased growth doesn’t necessarily correspond to increased crop yield. Using specially built plant growth chambers that can control the concentration of CO2, Des Marais will explore how CO2 availability impacts the development of tillers (branches) in the grass species Brachypodium. He will study how gene expression controls tiller development, and whether this is affected by the growing environment. The tillering response refers to how many branches a plant produces, which sets a limit on how much grain it can yield. Therefore, optimizing the tillering response to elevated CO2 could greatly increase yield. Des Marais will also look at the complete genome sequence of Brachypodium, wheat, oat, and barley to help identify genes relevant for branch growth.Darcy McRose, an assistant professor in the Department of Civil and Environmental Engineering, is researching whether a combination of plant metabolites and soil bacteria can be used to make mineral-associated phosphorus more bioavailable.The nutrient phosphorus is essential for agricultural plant growth, but when added as a fertilizer, phosphorus sticks to the surface of soil minerals, decreasing bioavailability, limiting plant growth, and accumulating residual phosphorus. Heavily fertilized agricultural soils often harbor large reservoirs of this type of mineral-associated “legacy” phosphorus. Redox transformations are one chemical process that can liberate mineral-associated phosphorus. However, this needs to be carefully controlled, as overly mobile phosphorus can lead to runoff and pollution of natural waters. Ideally, phosphorus would be made bioavailable when plants need it and immobile when they don’t. Many plants make small metabolites called coumarins that might be able to solubilize mineral-adsorbed phosphorus and be activated and inactivated under different conditions. McRose will use laboratory experiments to determine whether a combination of plant metabolites and soil bacteria can be used as a highly efficient and tunable system for phosphorus solubilization. She also aims to develop an imaging platform to investigate exchanges of phosphorus between plants and soil microbes.Many of the 2023 seed grants will support innovative technologies to monitor, quantify, and remediate various kinds of pollutants found in water. Two of the new projects address the problem of per- and polyfluoroalkyl substances (PFAS), human-made chemicals that have recently emerged as a global health threat. Known as “forever chemicals,” PFAS are used in many manufacturing processes. These chemicals are known to cause significant health issues including cancer, and they have become pervasive in soil, dust, air, groundwater, and drinking water. Unfortunately, the physical and chemical properties of PFAS render them difficult to detect and remove.Aristide Gumyusenge, the Merton C. Assistant Professor of Materials Science and Engineering, is using metal-organic frameworks for low-cost sensing and capture of PFAS. Most metal-organic frameworks (MOFs) are synthesized as particles, which complicates their high accuracy sensing performance due to defects such as intergranular boundaries. Thin, film-based electronic devices could enable the use of MOFs for many applications, especially chemical sensing. Gumyusenge’s project aims to design test kits based on two-dimensional conductive MOF films for detecting PFAS in drinking water. In early demonstrations, Gumyusenge and his team showed that these MOF films can sense PFAS at low concentrations. They will continue to iterate using a computation-guided approach to tune sensitivity and selectivity of the kits with the goal of deploying them in real-world scenarios.Carlos Portela, the Brit (1961) and Alex (1949) d’Arbeloff Career Development Professor in the Department of Mechanical Engineering, and Ariel Furst, the Cook Career Development Professor in the Department of Chemical Engineering, are building novel architected materials to act as filters for the removal of PFAS from water. Portela and Furst will design and fabricate nanoscale materials that use activated carbon and porous polymers to create a physical adsorption system. They will engineer the materials to have tunable porosities and morphologies that can maximize interactions between contaminated water and functionalized surfaces, while providing a mechanically robust system.Rohit Karnik is a Tata Professor and interim co-department head of the Department of Mechanical Engineering. He is working on another technology, his based on microbead sensors, to rapidly measure and monitor trace contaminants in water.Water pollution from both biological and chemical contaminants contributes to an estimated 1.36 million deaths annually. Chemical contaminants include pesticides and herbicides, heavy metals like lead, and compounds used in manufacturing. These emerging contaminants can be found throughout the environment, including in water supplies. The Environmental Protection Agency (EPA) in the United States sets recommended water quality standards, but states are responsible for developing their own monitoring criteria and systems, which must be approved by the EPA every three years. However, the availability of data on regulated chemicals and on candidate pollutants is limited by current testing methods that are either insensitive or expensive and laboratory-based, requiring trained scientists and technicians. Karnik’s project proposes a simple, self-contained, portable system for monitoring trace and emerging pollutants in water, making it suitable for field studies. The concept is based on multiplexed microbead-based sensors that use thermal or gravitational actuation to generate a signal. His proposed sandwich assay, a testing format that is appealing for environmental sensing, will enable both single-use and continuous monitoring. The hope is that the bead-based assays will increase the ease and reach of detecting and quantifying trace contaminants in water for both personal and industrial scale applications.Alexander Radosevich, a professor in the Department of Chemistry, and Timothy Swager, the John D. MacArthur Professor of Chemistry, are teaming up to create rapid, cost-effective, and reliable techniques for on-site arsenic detection in water.Arsenic contamination of groundwater is a problem that affects as many as 500 million people worldwide. Arsenic poisoning can lead to a range of severe health problems from cancer to cardiovascular and neurological impacts. Both the EPA and the World Health Organization have established that 10 parts per billion is a practical threshold for arsenic in drinking water, but measuring arsenic in water at such low levels is challenging, especially in resource-limited environments where access to sensitive laboratory equipment may not be readily accessible. Radosevich and Swager plan to develop reaction-based chemical sensors that bind and extract electrons from aqueous arsenic. In this way, they will exploit the inherent reactivity of aqueous arsenic to selectively detect and quantify it. This work will establish the chemical basis for a new method of detecting trace arsenic in drinking water.Rajeev Ram is a professor in the Department of Electrical Engineering and Computer Science. His J-WAFS research will advance a robust technology for monitoring nitrogen-containing pollutants, which threaten over 15,000 bodies of water in the United States alone.Nitrogen in the form of nitrate, nitrite, ammonia, and urea can run off from agricultural fertilizer and lead to harmful algal blooms that jeopardize human health. Unfortunately, monitoring these contaminants in the environment is challenging, as sensors are difficult to maintain and expensive to deploy. Ram and his students will work to establish limits of detection for nitrate, nitrite, ammonia, and urea in environmental, industrial, and agricultural samples using swept-source Raman spectroscopy. Swept-source Raman spectroscopy is a method of detecting the presence of a chemical by using a tunable, single mode laser that illuminates a sample. This method does not require costly, high-power lasers or a spectrometer. Ram will then develop and demonstrate a portable system that is capable of achieving chemical specificity in complex, natural environments. Data generated by such a system should help regulate polluters and guide remediation.Kripa Varanasi, a professor in the Department of Mechanical Engineering, and Angela Belcher, the James Mason Crafts Professor and head of the Department of Biological Engineering, will join forces to develop an affordable water disinfection technology that selectively identifies, adsorbs, and kills “superbugs” in domestic and industrial wastewater.Recent research predicts that antibiotic-resistance bacteria (superbugs) will result in $100 trillion in health care expenses and 10 million deaths annually by 2050. The prevalence of superbugs in our water systems has increased due to corroded pipes, contamination, and climate change. Current drinking water disinfection technologies are designed to kill all types of bacteria before human consumption. However, for certain domestic and industrial applications there is a need to protect the good bacteria required for ecological processes that contribute to soil and plant health. Varanasi and Belcher will combine material, biological, process, and system engineering principles to design a sponge-based water disinfection technology that can identify and destroy harmful bacteria while leaving the good bacteria unharmed. By modifying the sponge surface with specialized nanomaterials, their approach will be able to kill superbugs faster and more efficiently. The sponge filters can be deployed under very low pressure, making them an affordable technology, especially in resource-constrained communities.In addition to the 10 seed grant projects, J-WAFS will also fund a research initiative led by Greg Sixt. Sixt is the research manager for climate and food systems at J-WAFS, and the director of the J-WAFS-led Food and Climate Systems Transformation (FACT) Alliance. His project focuses on the Lake Victoria Basin (LVB) of East Africa. The second-largest freshwater lake in the world, Lake Victoria straddles three countries (Uganda, Tanzania, and Kenya) and has a catchment area that encompasses two more (Rwanda and Burundi). Sixt will collaborate with Michael Hauser of the University of Natural Resources and Life Sciences, Vienna, and Paul Kariuki, of the Lake Victoria Basin Commission.The group will study how to adapt food systems to climate change in the Lake Victoria Basin. The basin is facing a range of climate threats that could significantly impact livelihoods and food systems in the expansive region. For example, extreme weather events like droughts and floods are negatively affecting agricultural production and freshwater resources. Across the LVB, current approaches to land and water management are unsustainable and threaten future food and water security. The Lake Victoria Basin Commission (LVBC), a specialized institution of the East African Community, wants to play a more vital role in coordinating transboundary land and water management to support transitions toward more resilient, sustainable, and equitable food systems. The primary goal of this research will be to support the LVBC’s transboundary land and water management efforts, specifically as they relate to sustainability and climate change adaptation in food systems. The research team will work with key stakeholders in Kenya, Uganda, and Tanzania to identify specific capacity needs to facilitate land and water management transitions. The two-year project will produce actionable recommendations to the LVBC. More