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    Devices offers long-distance, low-power underwater communication

    MIT researchers have demonstrated the first system for ultra-low-power underwater networking and communication, which can transmit signals across kilometer-scale distances.

    This technique, which the researchers began developing several years ago, uses about one-millionth the power that existing underwater communication methods use. By expanding their battery-free system’s communication range, the researchers have made the technology more feasible for applications such as aquaculture, coastal hurricane prediction, and climate change modeling.

    “What started as a very exciting intellectual idea a few years ago — underwater communication with a million times lower power — is now practical and realistic. There are still a few interesting technical challenges to address, but there is a clear path from where we are now to deployment,” says Fadel Adib, associate professor in the Department of Electrical Engineering and Computer Science and director of the Signal Kinetics group in the MIT Media Lab.

    Underwater backscatter enables low-power communication by encoding data in sound waves that it reflects, or scatters, back toward a receiver. These innovations enable reflected signals to be more precisely directed at their source.

    Due to this “retrodirectivity,” less signal scatters in the wrong directions, allowing for more efficient and longer-range communication.

    When tested in a river and an ocean, the retrodirective device exhibited a communication range that was more than 15 times farther than previous devices. However, the experiments were limited by the length of the docks available to the researchers.

    To better understand the limits of underwater backscatter, the team also developed an analytical model to predict the technology’s maximum range. The model, which they validated using experimental data, showed that their retrodirective system could communicate across kilometer-scale distances.

    The researchers shared these findings in two papers which will be presented at this year’s ACM SIGCOMM and MobiCom conferences. Adib, senior author on both papers, is joined on the SIGCOMM paper by co-lead authors Aline Eid, a former postdoc who is now an assistant professor at the University of Michigan, and Jack Rademacher, a research assistant; as well as research assistants Waleed Akbar and Purui Wang, and postdoc Ahmed Allam. The MobiCom paper is also written by co-lead authors Akbar and Allam.

    Communicating with sound waves

    Underwater backscatter communication devices utilize an array of nodes made from “piezoelectric” materials to receive and reflect sound waves. These materials produce an electric signal when mechanical force is applied to them.

    When sound waves strike the nodes, they vibrate and convert the mechanical energy to an electric charge. The nodes use that charge to scatter some of the acoustic energy back to the source, transmitting data that a receiver decodes based on the sequence of reflections.

    But because the backscattered signal travels in all directions, only a small fraction reaches the source, reducing the signal strength and limiting the communication range.

    To overcome this challenge, the researchers leveraged a 70-year-old radio device called a Van Atta array, in which symmetric pairs of antennas are connected in such a way that the array reflects energy back in the direction it came from.

    But connecting piezoelectric nodes to make a Van Atta array reduces their efficiency. The researchers avoided this problem by placing a transformer between pairs of connected nodes. The transformer, which transfers electric energy from one circuit to another, allows the nodes to reflect the maximum amount of energy back to the source.

    “Both nodes are receiving and both nodes are reflecting, so it is a very interesting system. As you increase the number of elements in that system, you build an array that allows you to achieve much longer communication ranges,” Eid explains.

    In addition, they used a technique called cross-polarity switching to encode binary data in the reflected signal. Each node has a positive and a negative terminal (like a car battery), so when the positive terminals of two nodes are connected and the negative terminals of two nodes are connected, that reflected signal is a “bit one.”

    But if the researchers switch the polarity, and the negative and positive terminals are connected to each other instead, then the reflection is a “bit zero.”

    “Just connecting the piezoelectric nodes together is not enough. By alternating the polarities between the two nodes, we are able to transmit data back to the remote receiver,” Rademacher explains.

    When building the Van Atta array, the researchers found that if the connected nodes were too close, they would block each other’s signals. They devised a new design with staggered nodes that enables signals to reach the array from any direction. With this scalable design, the more nodes an array has, the greater its communication range.

    They tested the array in more than 1,500 experimental trials in the Charles River in Cambridge, Massachusetts, and in the Atlantic Ocean, off the coast of Falmouth, Massachusetts, in collaboration with the Woods Hole Oceanographic Institution. The device achieved communication ranges of 300 meters, more than 15 times longer than they previously demonstrated.

    However, they had to cut the experiments short because they ran out of space on the dock.

    Modeling the maximum

    That inspired the researchers to build an analytical model to determine the theoretical and practical communication limits of this new underwater backscatter technology.

    Building off their group’s work on RFIDs, the team carefully crafted a model that captured the impact of system parameters, like the size of the piezoelectric nodes and the input power of the signal, on the underwater operation range of the device.

    “It is not a traditional communication technology, so you need to understand how you can quantify the reflection. What are the roles of the different components in that process?” Akbar says.

    For instance, the researchers needed to derive a function that captures the amount of signal reflected out of an underwater piezoelectric node with a specific size, which was among the biggest challenges of developing the model, he adds.

    They used these insights to create a plug-and-play model into a which a user could enter information like input power and piezoelectric node dimensions and receive an output that shows the expected range of the system.

    They evaluated the model on data from their experimental trials and found that it could accurately predict the range of retrodirected acoustic signals with an average error of less than one decibel.

    Using this model, they showed that an underwater backscatter array can potentially achieve kilometer-long communication ranges.

    “We are creating a new ocean technology and propelling it into the realm of the things we have been doing for 6G cellular networks. For us, it is very rewarding because we are starting to see this now very close to reality,” Adib says.

    The researchers plan to continue studying underwater backscatter Van Atta arrays, perhaps using boats so they could evaluate longer communication ranges. Along the way, they intend to release tools and datasets so other researchers can build on their work. At the same time, they are beginning to move toward commercialization of this technology.

    “Limited range has been an open problem in underwater backscatter networks, preventing them from being used in real-world applications. This paper takes a significant step forward in the future of underwater communication, by enabling them to operate on minimum energy while achieving long range,” says Omid Abari, assistant professor of computer science at the University of California at Los Angeles, who was not involved with this work. “The paper is the first to bring Van Atta Reflector array technique into underwater backscatter settings and demonstrate its benefits in improving the communication range by orders of magnitude. This can take battery-free underwater communication one step closer to reality, enabling applications such as underwater climate change monitoring and coastal monitoring.”

    This research was funded, in part, by the Office of Naval Research, the Sloan Research Fellowship, the National Science Foundation, the MIT Media Lab, and the Doherty Chair in Ocean Utilization. More

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    Uncovering how biomes respond to climate change

    Before Leila Mirzagholi arrived at MIT’s Department of Civil and Environmental Engineering (CEE) to begin her postdoc appointment, she had spent most of her time in academia building cosmological models to detect properties of gravitational waves in the cosmos.

    But as a member of Assistant Professor César Terrer’s lab in CEE, Mirzagholi uses her physics and mathematical background to improve our understanding of the different factors that influence how much carbon land ecosystems can store under climate change.

    “What was always important to me was thinking about how to solve a problem and putting all the pieces together and building something from scratch,” Mirzagholi says, adding this was one of the reasons that it was possible for her to switch fields — and what drives her today as a climate scientist.

    Growing up in Iran, Mirzagholi knew she wanted to be a scientist from an early age. As a kid, she became captivated by physics, spending most of her free time in a local cultural center that hosted science events. “I remember in that center there was an observatory that held observational tours and it drew me into science,” says Mirzgholi. She also remembers a time when she was a kid watching the science fiction film “Contact” that introduces a female scientist character who finds evidence of extraterrestrial life and builds a spaceship to make first contact: “After that movie my mind was set on pursuing astrophysics.”

    With the encouragement of her parents to develop a strong mathematical background before pursuing physics, she earned a bachelor’s degree in mathematics from Tehran University. Then she completed a one-year master class in mathematics at Utrecht University before completing her PhD in theoretical physics at Max Planck Institute for Astrophysics in Munich. There, Mirzgholi’s thesis focused on developing cosmological models with a focus on phenomenological aspects like propagation of gravitational waves on the cosmic microwave background.

    Midway through her PhD, Mirzgholi became discouraged with building models to explain the dynamics of the early universe because there is little new data. “It starts to get personal and becomes a game of: ‘Is it my model or your model?’” she explains. She grew frustrated not knowing when the models she’d built would ever be tested.

    It was at this time that Mirzgholi started reading more about the topics of climate change and climate science. “I was really motivated by the problems and the nature of the problems, especially to make global terrestrial ecology more quantitative,” she says. She also liked the idea of contributing to a global problem that we are all facing. She started to think, “maybe I can do my part, I can work on research beneficial for society and the planet.”

    She made the switch following her PhD and started as a postdoc in the Crowther Lab at ETH Zurich, working on understanding the effects of environmental changes on global vegetation activity. After a stint at ETH, where her colleagues collaborated on projects with the Terrer Lab, she relocated to Cambridge, Massachusetts, to join the lab and CEE.

    Her latest article in Science, which was published in July and co-authored by researchers from ETH, shows how global warming affects the timing of autumn leaf senescence. “It’s important to understand the length of the growing season, and how much the forest or other biomes will have the capacity to take in carbon from the atmosphere.” Using remote sensing data, she was able to understand when the growing season will end under a warming climate. “We distinguish two dates — when autumn is onsetting and the leaves are starting to turn yellow, versus when the leaves are 50 percent yellow — to represent the progression of leaf senescence,” she says.

    In the context of rising temperature, when the warming is happening plays a crucial role. If warming temperatures happen before the summer solstice, it triggers trees to begin their seasonal cycles faster, leading to reduced photosynthesis, ending in an earlier autumn. On the other hand, if the warming happens after the summer solstice, it delays the discoloration process, making autumn last longer. “For every degree Celsius of pre-solstice warming, the onset of leaf senescence advances by 1.9 days, while each degree Celsius of post-solstice warming delays the senescence process by 2.6 days,” she explains. Understanding the timing of autumn leaf senescence is essential in efforts to predict carbon storage capacity when modeling global carbon cycles.

    Another problem she’s working on in the Terrer Lab is discovering how deforestation is changing our local climate. How much is it cooling or warming the temperature, and how is the hydrological cycle changing because of deforestation? Investigating these questions will give insight into how much we can depend on natural solutions for carbon uptake to help mitigate climate change. “Quantitatively, we want to put a number to the amount of carbon uptake from various natural solutions, as opposed to other solutions,” she says.

    With year-and-a-half left in her postdoc appointment, Mirzagholi has begun considering her next career steps. She likes the idea of applying to climate scientist jobs in industry or national labs, as well as tenure track faculty positions. Whether she pursues a career in academia or industry, Mirzagholi aims to continue conducting fundamental climate science research. Her multidisciplinary background in physics, mathematics, and climate science has given her a multifaceted perspective, which she applies to every research problem.

    “Looking back, I’m grateful for all my educational experiences from spending time in the cultural center as a kid, my background in physics, the support from colleagues at the Crowther lab at ETH who facilitated my transition from physics to ecology, and now working at MIT alongside Professor Terrer, because it’s shaped my career path and the researcher I am today.” More

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    Elsa Olivetti appointed associate dean of engineering

    Elsa Olivetti, the Jerry McAfee (1940) Professor in Engineering in the Department of Materials Science and Engineering, has been appointed as associate dean of engineering, effective Sept. 1.

    As associate dean, Olivetti will oversee a number of strategically important programs and initiatives across MIT’s School of Engineering. She will help lead and shape school-wide efforts related to climate and sustainability. In close collaboration with Nandi Bynoe, the assistant dean for diversity, equity, and inclusion; the school’s DEI faculty lead; and various program faculty leads, Olivetti will oversee the school’s DEI activities and programs. She will also assist with the faculty promotion process and will support both faculty and students across the school with regards fellowships, awards, and honors.

    “Professor Olivetti has demonstrated tremendous leadership abilities, particularly as co-director of the MIT Climate and Sustainability Consortium. Her contributions as a researcher, educator, and leader at MIT have been substantial,” says Anantha Chandrakasan, dean of the School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science. “I am thrilled to welcome her to the School of Engineering leadership team and look forward to closely with her in this new role.”

    Olivetti first joined MIT as a graduate student after receiving her bachelor’s degree in engineering science from the University of Virginia. As a PhD student in the Department of Materials Science and Engineering (DMSE), her research focused on electrochemistry in inorganic materials for use in lithium-ion batteries. Through postdoctoral research and a staff scientist position with the MIT Materials System Laboratory beginning in 2009, Olivetti developed methods for streamlined carbon footprinting of electronics, a method that is still used widely by the electronics industry.

    In 2014, Olivetti joined the DMSE faculty, where her team works in sustainable and scalable design, processing, and manufacturing of materials use across industries. The Olivetti Group develops experimental and analytical methods for efficient use of industrial waste and recycled materials in concrete, metals, and plastic guiding decisions on a plant floor to policy makers.

    Olivetti’s team has also developed methods to automatically learn from texts within materials ranging from inorganic materials synthesis, zeolites, solid state batteries, and cement. Her work uses an interdisciplinary approach combining industrial ecology with materials science and engineering to inform and then mitigate the environmental and economic impact of materials.

    Olivetti has lead climate and sustainability efforts across the Institute. She serves as the co-director of the MIT Climate and Sustainability Consortium (MCSC). Launched in 2021, the MCSC fosters collaboration between academia and industry in an effort to accelerate real-world solutions for the climate crisis at scale. Under Olivetti’s leadership alongside co-director Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems, and executive director Jeremy Gregory, the consortium has grown to 18 member companies and has provided 20 research projects with seed funding. It has also launched programs such as the MCSC Climate and Sustainability Scholars Program for undergraduate students and the MCSC Impact Fellows Program for postdocs.

    In addition to her leadership at the MCSC, Olivetti is a member of the MIT Climate Nucleus, a faculty committee responsible for the implementation of “Fast Forward: MIT’s Climate Action Plan for the Decade.”

    A dedicated educator, Olivetti has made significant contributions to MIT’s material science and engineering education. She was instrumental in the development of a refined DMSE undergraduate curriculum. She also launched a new class 3.081 (Industrial Ecology of Materials) and served as a founding thread lead for MIT New Engineering Education Transformation’s Advanced Materials Machines program. Olivetti launched “Course 3 Industry Seminars,” which provide undergraduate students an opportunity to learn from industry leaders in fields like manufacturing and environmental consulting.

    Throughout her career, Olivetti has received numerous awards and honors for both her commitment to students and her research contributions. She is the recipient of the 2017 Earll M. Murman Award for Excellence in Undergraduate Advising, a 2020 Paul Gray Award for Public Service, the 2021 Bose Teaching Award, 2021 MacVicar Faculty Fellowship, and the 2023 Capers (1976) and Marion McDonald Award for Excellence in Mentoring and Advising. She also received an Early Career Faculty Fellowship from the Minerals, Metals and Materials Society as well as a National Science Foundation Early Career Development Award.

    Olivetti joins Dean Chandrakasan and Deputy Dean Maria Yang, the Gail E. Kendall (1978) Professor, on the School of Engineering faculty leadership team. More

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    3 Questions: How are cities managing record-setting temperatures?

    July 2023 was the hottest month globally since humans began keeping records. People all over the U.S. experienced punishingly high temperatures this summer. In Phoenix, there were a record-setting 31 consecutive days with a high temperature of 110 degrees Fahrenheit or more. July was the hottest month on record in Miami. A scan of high temperatures around the country often yielded some startlingly high numbers: Dallas, 110 F; Reno, 108 F; Salt Lake City, 106 F; Portland, 105 F.

    Climate change is a global and national crisis that cannot be solved by city governments alone, but cities suffering from it can try to enact new policies reducing emissions and adapting its effects. MIT’s David Hsu, an associate professor of urban and environmental planning, is an expert on metropolitan and regional climate policy. In one 2017 paper, Hsu and some colleagues estimated how 11 major U.S. cities could best reduce their carbon dioxide emissions, through energy-efficient home construction and retrofitting, improvements in vehicle gas mileage, more housing density, robust transit systems, and more. As we near the end of this historically hot summer, MIT News talked to Hsu about what cities are now doing in response to record heat, and the possibilities for new policy measures.

    Q: We’ve had record-setting temperatures in many cities across the U.S. this summer. Dealing with climate change certainly isn’t just the responsibility of those cities, but what have they been doing to make a difference, to the extent they can?

    A: I think this is a very top-of-mind question because even 10 or 15 years ago, we talked about adapting to a changed climate future, which seemed further off. But literally every week this summer we can refer to [dramatic] things that are already happening, clearly linked to climate change, and are going to get worse. We had wildfire smoke in the Northeast and throughout the Eastern Seaboard in June, this tragic wildfire in Hawaii that led to more deaths than any other wildfire in the U.S., [plus record high temperatures]. A lot of city leaders face climate challenges they thought were maybe 20 or 30 years in the future, and didn’t expect to see happen with this severity and intensity.

    One thing you’re seeing is changes in governance. A lot of cities have recently appointed a chief heat officer. Miami and Phoenix have them now, and this is someone responsible for coordinating response to heat waves, which turn out to be one of the biggest killers among climatological effects. There is an increasing realization not only among local governments, but insurance companies and the building industry, that flooding is going to affect many places. We have already seen flooding in the seaport area in Boston, the most recently built part of our city. In some sense just the realization among local governments, insurers, building owners, and residents, that some risks are here and now, already is changing how people think about those risks.

    Q: To what extent does a city being active about climate change at least signal to everyone, at the state or national level, that we have to do more? At the same time, some states are reacting against cities that are trying to institute climate initiatives and trying to prevent clean energy advances. What is possible at this point?

    A: We have this very large, heterogeneous and polarized country, and we have differences between states and within states in how they’re approaching climate change. You’ve got some cities trying to enact things like natural gas bans, or trying to limit greenhouse gas emissions, with some state governments trying to preempt them entirely. I think cities have a role in showing leadership. But one thing I harp on, having worked in city government myself, is that sometimes in cities we can be complacent. While we pride ourselves on being centers of innovation and less per-capita emissions — we’re using less than rural areas, and you’ll see people celebrating New York City as the greenest in the world — cities are responsible for consumption that produces a majority of emissions in most countries. If we’re going to decarbonize society, we have to get to zero altogether, and that requires cities to act much more aggressively.

    There is not only a pessimistic narrative. With the Inflation Reduction Act, which is rapidly accelerating the production of renewable energy, you see many of those subsidies going to build new manufacturing in red states. There’s a possibility people will see there are plenty of better paying, less dangerous jobs in [clean energy]. People don’t like monopolies wherever they live, so even places people consider fairly conservative would like local control [of energy], and that might mean greener jobs and lower prices. Yes, there is a doomscrolling loop of thinking polarization is insurmountable, but I feel surprisingly optimistic sometimes.

    Large parts of the Midwest, even in places people think of as being more conservative, have chosen to build a lot of wind energy, partly because it’s profitable. Historically, some farmers were self-reliant and had wind power before the electrical grid came. Even now in some places where people don’t want to address climate change, they’re more than happy to have wind power.

    Q: You’ve published work on which cities can pursue which policies to reduce emissions the most: better housing construction, more transit, more fuel-efficient vehicles, possibly higher housing density, and more. The exact recipe varies from place to place. But what are the common threads people can think about?

    A: It’s important to think about what the status quo is, and what we should be preparing for. The status quo simply doesn’t serve large parts of the population right now. Heat risk, flooding, and wildfires all disproportionately affect populations that are already vulnerable. If you’re elderly, or lack access to mobility, information, or warnings, you probably have a lower risk of surviving a wildfire. Many people do not have high-quality housing, and may be more exposed to heat or smoke. We know the climate has already changed, and is going to change more, but we have failed to prepare for foreseeable changes that already here. Lots of things that are climate-related but not only about climate change, like affordable housing, transportation, energy access for everyone so they can have services like cooking and the internet — those are things that we can change going forward. The hopeful message is: Cities are always changing and being built, so we should make them better. The urgent message is: We shouldn’t accept the status quo. More

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    Putting public service into practice

    Salomé Otero ’23 doesn’t mince words about the social impact internship she had in 2022. “It was transformational for me,” she says.

    Otero, who majored in management with a concentration in education, always felt that education would play some role in her career path after MIT, but she wasn’t sure how. That all changed her junior year, when she got an email from the Priscilla King Gray Public Service Center (PKG Center) about an internship at The Last Mile, a San Francisco-based nonprofit that provides education and technology training for justice-impacted individuals.

    Otero applied and was selected as a web curriculum and re-entry intern at The Last Mile the summer between her junior and senior year — an eye-opening experience that cemented her post-graduation plans. “You hear some amazing stories, like this person was incarcerated before the iPhone had come out. Now he’s a software developer,” she explains. “And for me, the idea of using computer science education for good appealed to me on many fronts. But even if I hadn’t gotten the opportunity to work at The Last Mile, the fact that I saw a job description for this role and learned that companies have the resources to make a difference … I didn’t know that there were people and organizations dedicating their time and energy into this.”

    She was so inspired that, when she returned for her senior year, Otero found work at two education labs at MIT, completed another social impact internship over Independent Activities Period (IAP) at G{Code}, an education nonprofit that provides computer science education to women and nonbinary people of color, and decided to apply to graduate school. “I can tell you with 100 percent certainty that I would not be pursuing a PhD in education policy right now if it weren’t for the PKG Center,” she says. She will begin her doctorate this fall.

    Otero’s experience doesn’t surprise Jill Bassett, associate dean and director of the PKG Center. “MIT students are deeply concerned about the world’s most challenging problems,” she says. “And social impact internships are an incredible way for them to leverage their unique talents and skills to help create meaningful change while broadening their perspectives and discovering potential career paths.”

    “There’s a lot more out there”

    Founded 35 years ago, the PKG Center offers a robust portfolio of experiential learning programs broadly focused on four themes: climate change, health equity, racial justice, and tech for social good. The Center’s Social Impact Internship Program provides funded internships to students interested in working with government agencies, nonprofits, and social ventures. Students reap rich rewards from these experiences, including learning ways to make social change, informing their academic journey and career path, and gaining valuable professional skills.

    “It was a really good learning opportunity,” says Juliet Liao ’23, a graduate of MIT’s Naval ROTC program who commissioned as a submarine officer in June. She completed a social impact internship with the World Wildlife Fund, where she researched greenhouse gas emissions related to the salmon industry. “I haven’t had much exposure to what work outside of the Navy looks like and what I’m interested in working on. And I really liked the science-based approach to mitigating greenhouse gas emissions.”

    Amina Abdalla, a rising junior in biological engineering, arrived at MIT with a strong interest in health care and determined to go to medical school. But her internship at MassHealth, the Medicaid and Children’s Health Insurance Program provider for the state of Massachusetts, broadened her understanding of the complexity of the health care system and introduced her to many career options that she didn’t know existed.

    “They did coffee chats between interns and various people who work in MassHealth, such as doctors, lawyers, policy advocates, and consultants. There’s a lot more out there that one can do with the degree that they get and the knowledge they gain. It just depends on your interests, and I came away from that really excited,” she says. The experience inspired her to take a class in health policy before she graduates. “I know I want to be a doctor and I have a lot of interest in science in general, but if I could do some kind of public sector impact with that knowledge, I would definitely be interested in doing that.”

    Social impact internships also provide an opportunity for students to hone their analytical, technical, and people skills. Selma Sharaf ’22 worked on developing a first-ever climate action plan for Bennett College in Greensboro, North Carolina, one of two all-women’s historically Black colleges and universities in the United States. She conducted research and stakeholder interviews with nonprofits; sustainability directors at similar colleges; local utility companies; and faculty, staff, and students at Bennett.

    “Our external outreach efforts with certain organizations allowed me to practice having conversations about energy justice and climate issues with people who aren’t already in this space. I learned how useful it can be to not only discuss the overall issues of climate change and carbon emissions, but to also zoom in on more relatable personal-level impacts,” she says. Sharaf is currently working in clean energy consulting and plans to pursue a master’s degree at Stanford University’s Atmosphere/Energy Program this fall.

    Working with “all stars”

    Organizations that partner with the PKG Center are often constrained by limited technical and financial resources. Since the program is funded by the PKG Center, these internships help expand their organizational capacity and broaden their impact; MIT students can take on projects that might not otherwise get done, and they also bring fresh skills and ideas to the organization — and the zeal to pursue those ideas.

    Emily Moberg ’11, PhD ’16 got involved with the social impact internship programs in 2020. Moberg, who is the director of Scope 3 Carbon Measurement and Mitigation at the World Wildlife Fund, has worked with 20 MIT students since then, including Liao. The body of work that Liao and several other interns completed has been published in the form of 10 briefs onmitigating greenhouse gas emissions from key commodities, such as soy, beef, coffee, and palm oil.

    “Social impact interns bring technical skills, deep curiosity, and tenacity,” Moberg says. “I’ve worked with students across many majors, including computer and materials science; all of them bring a new, fresh perspective to our problems and often sophisticated quantitative ability. Their presence often helps us to investigate new ideas or expand a project. In some cases, interns have proposed new projects and ideas themselves. The support from the PKG Center for us to host these interns has been critical, especially for these new explorations.”

    Anne Carrington Hayes, associate professor and executive director of the Global Leadership and Interdisciplinary Studies program at Bennett College, calls the MIT interns she’s worked with since 2021 “all stars.” The work Sharaf and three other students performed has culminated in a draft climate action plan that will inform campus renovations and other measures that will be implemented at the college in the coming years.

    “They have been foundational in helping me to research, frame, collect data, and engage with our students and the community around issues of environmental justice and sustainability, particularly from the lens of what would be impactful and meaningful for women of color at Bennett College,” she says.

    Balancing supply and demand

    Bassett says that the social impact internship program has grown exponentially in the past few years. Before the pandemic, the program served five students from summer 2019 to spring 2020; it now serves about 125 students per year. Over that time, funding has become a significant limiting factor; demand for internships was three times the number of available internships in summer 2022, and five times the supply during IAP 2023.

    “MIT students have no shortage of opportunities available to them in the private sector, yet students are seeking social impact internships because they want to apply their skills to issues that they care about,” says Julie Uva, the PKG Center’s program administrator for social impact internships and employment. “We want to ensure every student who wants a social impact internship can access that experience.”

    MIT has taken note of this financial shortfall: the Task Force 2021 report recommended fundraising to alleviate the under-supply of social impact experiential learning opportunities (ELOs), and MIT’s Fast Forward Climate Action Plan called on the Institute to make a climate or clean-energy ELOs available to every undergraduate who wants one. As a result, the Office of Experiential Learning is working with Resource Development to raise new funding to support many more opportunities, which would be available to students not only through the PKG Center but also other offices and programs, such as MIT D-Lab, Undergraduate Research Opportunity Programs, MISTI, and the Environmental Solutions Initiative, among others.

    That’s welcome news to Salomé Otero. She’s familiar with the Institute’s fundraising efforts, having worked as one of the Alumni Association’s Tech Callers. Now, as an alumna herself and a former social impact intern, she has an appreciation for the power of philanthropy.

    “MIT is ahead of the game compared to so many universities, in so many ways,” she says. “But if they want to continue to do that in the most impactful way possible, I think investing in ideas and missions like the PKG Center is the way to go. So when that call comes, I’ll tell whoever is working that night shift, ‘Yeah, I’ll donate to the PKG Center.’” More

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    New clean air and water labs to bring together researchers, policymakers to find climate solutions

    MIT’s Abdul Latif Jameel Poverty Action Lab (J-PAL) is launching the Clean Air and Water Labs, with support from Community Jameel, to generate evidence-based solutions aimed at increasing access to clean air and water.

    Led by J-PAL’s Africa, Middle East and North Africa (MENA), and South Asia regional offices, the labs will partner with government agencies to bring together researchers and policymakers in areas where impactful clean air and water solutions are most urgently needed.

    Together, the labs aim to improve clean air and water access by informing the scaling of evidence-based policies and decisions of city, state, and national governments that serve nearly 260 million people combined.

    The Clean Air and Water Labs expand the work of J-PAL’s King Climate Action Initiative, building on the foundational support of King Philanthropies, which significantly expanded J-PAL’s work at the nexus of climate change and poverty alleviation worldwide. 

    Air pollution, water scarcity and the need for evidence 

    Africa, MENA, and South Asia are on the front lines of global air and water crises. 

    “There is no time to waste investing in solutions that do not achieve their desired effects,” says Iqbal Dhaliwal, global executive director of J-PAL. “By co-generating rigorous real-world evidence with researchers, policymakers can have the information they need to dedicate resources to scaling up solutions that have been shown to be effective.”

    In India, about 75 percent of households did not have drinking water on premises in 2018. In MENA, nearly 90 percent of children live in areas facing high or extreme water stress. Across Africa, almost 400 million people lack access to safe drinking water. 

    Simultaneously, air pollution is one of the greatest threats to human health globally. In India, extraordinary levels of air pollution are shortening the average life expectancy by five years. In Africa, rising indoor and ambient air pollution contributed to 1.1 million premature deaths in 2019. 

    There is increasing urgency to find high-impact and cost-effective solutions to the worsening threats to human health and resources caused by climate change. However, data and evidence on potential solutions are limited.

    Fostering collaboration to generate policy-relevant evidence 

    The Clean Air and Water Labs will foster deep collaboration between government stakeholders, J-PAL regional offices, and researchers in the J-PAL network. 

    Through the labs, J-PAL will work with policymakers to:

    co-diagnose the most pressing air and water challenges and opportunities for policy innovation;
    expand policymakers’ access to and use of high-quality air and water data;
    co-design potential solutions informed by existing evidence;
    co-generate evidence on promising solutions through rigorous evaluation, leveraging existing and new data sources; and
    support scaling of air and water policies and programs that are found to be effective through evaluation. 
    A research and scaling fund for each lab will prioritize resources for co-generated pilot studies, randomized evaluations, and scaling projects. 

    The labs will also collaborate with C40 Cities, a global network of mayors of the world’s leading cities that are united in action to confront the climate crisis, to share policy-relevant evidence and identify opportunities for potential new connections and research opportunities within India and across Africa.

    This model aims to strengthen the use of evidence in decision-making to ensure solutions are highly effective and to guide research to answer policymakers’ most urgent questions. J-PAL Africa, MENA, and South Asia’s strong on-the-ground presence will further bridge research and policy work by anchoring activities within local contexts. 

    “Communities across the world continue to face challenges in accessing clean air and water, a threat to human safety that has only been exacerbated by the climate crisis, along with rising temperatures and other hazards,” says George Richards, director of Community Jameel. “Through our collaboration with J-PAL and C40 in creating climate policy labs embedded in city, state, and national governments in Africa and South Asia, we are committed to innovative and science-based approaches that can help hundreds of millions of people enjoy healthier lives.”

    J-PAL Africa, MENA, and South Asia will formally launch Clean Air and Water Labs with government partners over the coming months. J-PAL is housed in the MIT Department of Economics, within the School of Humanities, Arts, and Social Sciences. More

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    Explained: The 1.5 C climate benchmark

    The summer of 2023 has been a season of weather extremes.

    In June, uncontrolled wildfires ripped through parts of Canada, sending smoke into the U.S. and setting off air quality alerts in dozens of downwind states. In July, the world set the hottest global temperature on record, which it held for three days in a row, then broke again on day four.

    From July into August, unrelenting heat blanketed large parts of Europe, Asia, and the U.S., while India faced a torrential monsoon season, and heavy rains flooded regions in the northeastern U.S. And most recently, whipped up by high winds and dry vegetation, a historic wildfire tore through Maui, devastating an entire town.

    These extreme weather events are mainly a consequence of climate change driven by humans’ continued burning of coal, oil, and natural gas. Climate scientists agree that extreme weather such as what people experienced this summer will likely grow more frequent and intense in the coming years unless something is done, on a persistent and planet-wide scale, to rein in global temperatures.

    Just how much reining-in are they talking about? The number that is internationally agreed upon is 1.5 degrees Celsius. To prevent worsening and potentially irreversible effects of climate change, the world’s average temperature should not exceed that of preindustrial times by more than 1.5 degrees Celsius (2.7 degrees Fahrenheit).

    As more regions around the world face extreme weather, it’s worth taking stock of the 1.5-degree bar, where the planet stands in relation to this threshold, and what can be done at the global, regional, and personal level, to “keep 1.5 alive.”

    Why 1.5 C?

    In 2015, in response to the growing urgency of climate impacts, nearly every country in the world signed onto the Paris Agreement, a landmark international treaty under which 195 nations pledged to hold the Earth’s temperature to “well below 2 degrees Celsius above pre-industrial levels,” and going further, aim to “limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels.”

    The treaty did not define a particular preindustrial period, though scientists generally consider the years from 1850 to 1900 to be a reliable reference; this time predates humans’ use of fossil fuels and is also the earliest period when global observations of land and sea temperatures are available. During this period, the average global temperature, while swinging up and down in certain years, generally hovered around 13.5 degrees Celsius, or 56.3 degrees Fahrenheit.

    The treaty was informed by a fact-finding report which concluded that, even global warming of 1.5 degrees Celsius above the preindustrial average, over an extended, decades-long period, would lead to high risks for “some regions and vulnerable ecosystems.” The recommendation then, was to set the 1.5 degrees Celsius limit as a “defense line” — if the world can keep below this line, it potentially could avoid the more extreme and irreversible climate effects that would occur with a 2 degrees Celsius increase, and for some places, an even smaller increase than that.

    But, as many regions are experiencing today, keeping below the 1.5 line is no guarantee of avoiding extreme, global warming effects.

    “There is nothing magical about the 1.5 number, other than that is an agreed aspirational target. Keeping at 1.4 is better than 1.5, and 1.3 is better than 1.4, and so on,” says Sergey Paltsev, deputy director of MIT’s Joint Program on the Science and Policy of Global Change. “The science does not tell us that if, for example, the temperature increase is 1.51 degrees Celsius, then it would definitely be the end of the world. Similarly, if the temperature would stay at 1.49 degrees increase, it does not mean that we will eliminate all impacts of climate change. What is known: The lower the target for an increase in temperature, the lower the risks of climate impacts.”

    How close are we to 1.5 C?

    In 2022, the average global temperature was about 1.15 degrees Celsius above preindustrial levels. According to the World Meteorological Organization (WMO), the cyclical weather phenomenon La Niña recently contributed to temporarily cooling and dampening the effects of human-induced climate change. La Niña lasted for three years and ended around March of 2023.

    In May, the WMO issued a report that projected a significant likelihood (66 percent) that the world would exceed the 1.5 degrees Celsius threshold in the next four years. This breach would likely be driven by human-induced climate change, combined with a warming El Niño — a cyclical weather phenomenon that temporarily heats up ocean regions and pushes global temperatures higher.

    This summer, an El Niño is currently underway, and the event typically raises global temperatures in the year after it sets in, which in this case would be in 2024. The WMO predicts that, for each of the next four years, the global average temperature is likely to swing between 1.1 and 1.8 degrees Celsius above preindustrial levels.

    Though there is a good chance the world will get hotter than the 1.5-degree limit as the result of El Niño, the breach would be temporary, and for now, would not have failed the Paris Agreement, which aims to keep global temperatures below the 1.5-degree limit over the long term (averaged over several decades rather than a single year).

    “But we should not forget that this is a global average, and there are variations regionally and seasonally,” says Elfatih Eltahir, the H.M. King Bhumibol Professor and Professor of Civil and Environmental Engineering at MIT. “This year, we had extreme conditions around the world, even though we haven’t reached the 1.5 C threshold. So, even if we control the average at a global magnitude, we are going to see events that are extreme, because of climate change.”

    More than a number

    To hold the planet’s long-term average temperature to below the 1.5-degree threshold, the world will have to reach net zero emissions by the year 2050, according to the Intergovernmental Panel on Climate Change (IPCC). This means that, in terms of the emissions released by the burning of coal, oil, and natural gas, the entire world will have to remove as much as it puts into the atmosphere.

    “In terms of innovations, we need all of them — even those that may seem quite exotic at this point: fusion, direct air capture, and others,” Paltsev says.

    The task of curbing emissions in time is particularly daunting for the United States, which generates the most carbon dioxide emissions of any other country in the world.

    “The U.S.’s burning of fossil fuels and consumption of energy is just way above the rest of the world. That’s a persistent problem,” Eltahir says. “And the national statistics are an aggregate of what a lot of individuals are doing.”

    At an individual level, there are things that can be done to help bring down one’s personal emissions, and potentially chip away at rising global temperatures.

    “We are consumers of products that either embody greenhouse gases, such as meat, clothes, computers, and homes, or we are directly responsible for emitting greenhouse gases, such as when we use cars, airplanes, electricity, and air conditioners,” Paltsev says. “Our everyday choices affect the amount of emissions that are added to the atmosphere.”

    But to compel people to change their emissions, it may be less about a number, and more about a feeling.

    “To get people to act, my hypothesis is, you need to reach them not just by convincing them to be good citizens and saying it’s good for the world to keep below 1.5 degrees, but showing how they individually will be impacted,” says Eltahir, who specializes on the study of regional climates, focusing on how climate change impacts the water cycle and frequency of extreme weather such as heat waves.

    “True climate progress requires a dramatic change in how the human system gets its energy,” Paltsev says. “It is a huge undertaking. Are you ready personally to make sacrifices and to change the way of your life? If one gets an honest answer to that question, it would help to understand why true climate progress is so difficult to achieve.” More

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    Tiny magnetic beads produce an optical signal that could be used to quickly detect pathogens

    Getting results from a blood test can take anywhere from one day to a week, depending on what a test is targeting. The same goes for tests of water pollution and food contamination. And in most cases, the wait time has to do with time-consuming steps in sample processing and analysis.

    Now, MIT engineers have identified a new optical signature in a widely used class of magnetic beads, which could be used to quickly detect contaminants in a variety of diagnostic tests. For example, the team showed the signature could be used to detect signs of the food contaminant Salmonella.

    The so-called Dynabeads are microscopic magnetic beads that can be coated with antibodies that bind to target molecules, such as a specific pathogen. Dynabeads are typically used in experiments in which they are mixed into solutions to capture molecules of interest. But from there, scientists have to take additional, time-consuming steps to confirm that the molecules are indeed present and bound to the beads.

    The MIT team found a faster way to confirm the presence of Dynabead-bound pathogens, using optics, specifically, Raman spectroscopy. This optical technique identifies specific molecules based on their “Raman signature,” or the unique way in which a molecule scatters light.

    The researchers found that Dynabeads have an unusually strong Raman signature that can be easily detected, much like a fluorescent tag. This signature, they found, can act as a “reporter.” If detected, the signal can serve as a quick confirmation, within less than one second, that a target pathogen is indeed present in a given sample. The team is currently working to develop a portable device for quickly detecting a range of bacterial pathogens, and their results will appear in an Emerging Investigators special issue of the Journal of Raman Spectroscopy.

    “This technique would be useful in a situation where a doctor is trying to narrow down the source of an infection in order to better inform antibiotic prescription, as well as for the detection of known pathogens in food and water,” says study co-author Marissa McDonald, a graduate student in the Harvard-MIT Program in Health Sciences and Technology. “Additionally, we hope this approach will eventually lead to expanded access to advanced diagnostics in resource-limited environments.”

    Study co-authors at MIT include Postdoctoral Associate Jongwan Lee; Visiting Scholar Nikiwe Mhlanga; Research Scientist Jeon Woong Kang; Tata Professor Rohit Karnik, who is also the associate director of the Abdul Latif Jameel Water and Food Systems Lab; and Assistant Professor Loza Tadesse of the Department of Mechanical Engineering.

    Oil and water

    Looking for diseased cells and pathogens in fluid samples is an exercise in patience.

    “It’s kind of a needle-in-a-haystack problem,” Tadesse says.

    The numbers present are so small that they must be grown in controlled environments to sufficient numbers, and their cultures stained, then studied under a microscope. The entire process can take several days to a week to yield a confident positive or negative result.

    Both Karnik and Tadesse’s labs have independently been developing techniques to speed up various parts of the pathogen testing process and make the process portable, using Dynabeads.

    Dynabeads are commercially available microscopic beads made from a magnetic iron core and a polymer shell that can be coated with antibodies. The surface antibodies act as hooks to bind specific target molecules. When mixed with a fluid, such as a vial of blood or water, any molecules present will glom onto the Dynabeads. Using a magnet, scientists can gently coax the beads to the bottom of a vial and filter them out of a solution. Karnik’s lab is investigating ways to then further separate the beads into those that are bound to a target molecule, and those that are not. “Still, the challenge is, how do we know that we have what we’re looking for?” Tadesse says.

    The beads themselves are not visible by eye. That’s where Tadesse’s work comes in. Her lab uses Raman spectroscopy as a way to “fingerprint” pathogens. She has found that different cell types scatter light in unique ways that can be used as a signature to identify them.

    In the team’s new work, she and her colleagues found that Dynabeads also have a unique and strong Raman signature that can act as a surprisingly clear beacon.

    “We were initially seeking to identify the signatures of bacteria, but the signature of the Dynabeads was actually very strong,” Tadesse says. “We realized this signal could be a means of reporting to you whether you have that bacteria or not.”

    Testing beacon

    As a practical demonstration, the researchers mixed Dynabeads into vials of water contaminated with Salmonella. They then magnetically isolated these beads onto microscope slides and measured the way light scattered through the fluid when exposed to laser light. Within half a second, they quickly detected the Dynabeads’ Raman signature — a confirmation that bound Dynabeads, and by inference, Salmonella, were present in the fluid.

    “This is something that can be used to rapidly give a positive or negative answer: Is there a contaminant or not?” Tadesse says. “Because even a handful of pathogens can cause clinical symptoms.”

    The team’s new technique is significantly faster than conventional methods and uses elements that could be adapted into smaller, more portable forms — a goal that the researchers are currently working toward. The approach is also highly versatile.

    “Salmonella is the proof of concept,” Tadesse says. “You could purchase Dynabeads with E.coli antibodies, and the same thing would happen: It would bind to the bacteria, and we’d be able to detect the Dynabead signature because the signal is super strong.”

    The team is particularly keen to apply the test to conditions such as sepsis, where time is of the essence, and where pathogens that trigger the condition are not rapidly detected using conventional lab tests.

    “There are a lot cases, like in sepsis, where pathogenic cells cannot always be grown on a plate,” says Lee, a member of Karnik’s lab. “In that case, our technique could rapidly detect these pathogens.”

    This research was supported, in part, by the MIT Laser Biomedical Research Center, the National Cancer Institute, and the Abdul Latif Jameel Water and Food Systems Lab at MIT. More