Wednesday, July 20th, 2016

Time	Event
12:00a	Seeking big answers As a PhD student in philosophy, Rebecca Millsop is working on doctoral research that’s a little different than most at MIT. “It’s thinking, writing, talking to people, doing some more thinking, and reading every once in a while,” she says with a laugh. However, for her this process has been a highly fruitful one that has led her to successfully address a highly contentious question in philosophy: How do we define art? Combining art and logic After high school, Millsop enrolled in the San Francisco Art Institute, where she studied conceptual art. She and her classmates spent their time creating art and critiquing each other’s work, and it was this process that pushed her to start thinking about the definition of art. “My second year I started considering the fact that I'm not going to be able to make art unless I know what it is,” she recalls. “So I decided to drop out of art school and study philosophy.” Millsop’s quest for answers landed her in a philosophy program at the City College of San Francisco, and it was there that she fell in love with logic, which she continued to pursue while earning her bachelor’s degree at the University of California at Berkeley. As an undergraduate, Millsop delved into areas of logic ranging from structural (what happens when you take all the content out of a logic problem and look at the connectors such as “and” and “or” that are left behind) to historical (her honors thesis explores the work of famous philosopher Immanuel Kant.) It was when Millsop read a paper by MIT philosophy professor Vann McGee, however, that her next step became clear.    “I was actually really frustrated with the paper. I was really challenged by the paper,” she says. “But I really loved it, so I wanted to go to MIT.” Millsop arrived at MIT with the goal of doing logic and mathematics, and for the first two years of her PhD that’s exactly what she did — until a class on the philosophy of social science with Ford International Professor Sally Haslanger, which caused her earlier questions about art to resurface. “I was reminded of being in art school and thinking about how difficult it was for a lot of individuals to engage with contemporary art because of its rarefied nature and the institution of art making it difficult for people to approach the nature of art itself,” she says. “I can remember sitting in this seminar and really feeling for the first time in graduate school that, yes, I have real opinions about this, this is something that I feel is important. The passion was there.” Of course, there was one complication — no one at MIT conducts research in the philosophy of art. However, Millsop wasn’t fazed, and she found plenty of support among the faculty in the philosophy department. What is art? For her dissertation, Millsop decided to tackle the biggest question that drove her to leave art school so many years before: What is art? To get at this question, she had to consider the three main existing definitions of art: the aesthetic (which relies completely on subjective viewer experience), institutional (where art is anything museums or galleries consider art), and historical (where current art is defined by those things considered art in the past). Each of these definitions excludes important examples of art, to the point where some philosophers decided maybe art just can’t be defined, an outcome Millsop found wholly unsatisfying. “You have to consider that art is a very real part of our lives and societies, we have art institutions, we have funding for the arts, everyone has an idea of what it is,” she says. “[Works of art] are real things that interact with real people in the world, so we should care about coming up with satisfactory definitions, or at least theories.”   The starting point of Millsop’s quest came from an unlikely place: biology. Specifically, species pluralism, the theory that comes out of the fact that there are 20 different definitions of a species used by biologists in different contexts.   “Some of these definitions can’t even capture everything that we want to capture at all,” says Millsop. “However, biologists work with all of them just fine, and they use them for different things. The idea with art pluralism is just taking that idea and plopping it into art.” Millsop got to work reading dozens of papers in the philosophy of biology, and devoted part one of her dissertation to strengthening the argument for art pluralism put forth in an earlier work by philosophers Christy Mag Uidhir and P.D. Magnus. Millsop used species pluralism to make the case for art pluralism, but by the end of her paper, she was brimming with new questions, such as how do the definitions of art relate to each other? Is there some unifying quality? In part two of her dissertation, Millsop took on some of these questions, arguing that pluralism involves multiple definitions having a specific structural relationship to one another (termed a “complex kind”), which is essentially the all-encompassing definition for that thing. Again, she relied on species pluralism in biology to make her point, explaining that there isn’t just one, catch-all definition of a species, but rather a variety of related definitions that come together in a specific structure.    Once she had successfully explained the concept of a complex kind, Millsop was finally ready to use it to answer her original question: What is art? To do so, Millsop devoted part three of her dissertation to figuring out the structural relationship that exists between the aesthetic, institutional, and historical definitions of art. Her conclusion? The aesthetic definition of art, which relies on subjective viewer experience is, in many ways, the most important one. “The aesthetic experiences we have with works of art give us the freedom to think about the artwork unconstrained by a lot of the typical assumptions and rules and moral boundaries that we have in everyday life,” she says. “They allow for this conversation between you and the artwork exploring what's right, what's wrong, how the world is, what other cultures are like. I think that's why we have art institutions. I think that's why art can change people's minds, can have political power, can be propaganda. It has a certain kind of power that can be harnessed for good or bad.” Of course, the institutional and historical definitions of art still must be factored in, and Millsop considers them to be “focally looping” on the aesthetic, meaning they influence our conversations about art, and play a role in the evolution of art over time. They also work well as real-world definitions of art, since they are more concrete. New challenges For Millsop, the final stage of her dissertation has provided a satisfying answer to her initial question, but it has also given her a lot more to think about. In particular, she has been grappling with how she can engage people in her research and how art in general can be made accessible for a general audience, which has led her to delve into the philosophy of education. “We really need to focus on how we teach art, because a lot of people don't think of art as the aesthetic, experiential, valuable thing that I'm talking about,” she explains. “We need to educate every individual in our society to feel comfortable and empowered to go up to a work of art and reflect on it from their own perspective, and feel like they are coming from a place of power.” Millsop uncovered her own love of teaching while teaching undergraduate philosophy classes at MIT, and as she nears the end of her doctoral program, she has begun thinking about ways to focus her academic research and praxis to art education, and she is also considering expanding her dissertation into a book aimed at a general audience.   It was no accident that around the same time Millsop switched her dissertation topic to the definition of art, she also restarted her own painting practice. Throughout graduate school, it has provided her with a much-needed outlet, a sanctuary where she can temporarily set aside all of her deep philosophical questions and reconnect with art on the most fundamental level — by creating it.  (Comment on this)
1:00p	Cancer-fighting bacteria Researchers at MIT and the University of California at San Diego (UCSD) have recruited some new soldiers in the fight against cancer — bacteria. In a study appearing in the July 20 of Nature, the scientists programmed harmless strains of bacteria to deliver toxic payloads. When deployed together with a traditional cancer drug, the bacteria shrank aggressive liver tumors in mice much more effectively than either treatment alone. The new approach exploits bacteria’s natural tendency to accumulate at disease sites. Certain strains of bacteria thrive in low-oxygen environments such as tumors, and suppression of the host’s immune system also creates favorable conditions for bacteria to flourish. “Tumors can be friendly environments for bacteria to grow, and we’re taking advantage of that,” says Sangeeta Bhatia, who is the John and Dorothy Wilson Professor of Health Sciences and Electrical Engineering and Computer Science at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research and its Institute for Medical Engineering and Science. Bhatia and Jeff Hasty, a professor of bioengineering at UCSD, are the senior authors of the paper. Lead authors are UCSD graduate student Omar Din and former MIT postdoc Tal Danino, who is now an assistant professor of biomedical engineering at Columbia University. Tumor-killing circuits The research team began looking into the possibility of harnessing bacteria to fight cancer several years ago. In a study published last year focusing on cancer diagnosis, the researchers engineered a strain of probiotic bacteria (similar to those found in yogurt) to express a genetic circuit that produces a luminescent signal, detectable with a simple urine test, if liver cancer is present. These harmless strains of E. coli, which can be either injected or consumed orally, tend to accumulate in the liver because one of the liver’s jobs is to filter bacteria out of the bloodstream. In their new study, the researchers delivered artificial genetic circuits into the bacteria, that allow the microbes to kill cancer cells in three different ways. One circuit produces a molecule called hemolysin, which destroys tumor cells by damaging their cell membranes. Another produces a drug that induces the cell to undergo programmed suicide, and the third circuit releases a protein that stimulates the body’s immune system to attack the tumor. To prevent potential side effects from these drugs, the researchers added another genetic circuit that allows the cells to detect how many other bacteria are in their environment, through a process known as quorum sensing. When the population reaches a predetermined target level, the bacterial cells self-destruct, releasing their toxic contents all at once. A few of the cells survive to begin the cycle again, which takes about 18 hours, allowing for repeated release of the drugs. “That allows us to maintain the burden of the bacteria in the whole organism at a low level and to keep pumping the drugs only into the tumor,” Bhatia says. Combination therapy The researchers tested the bacteria in mice with a very aggressive form of colon cancer that spreads to the liver. The bacteria accumulated in the liver and began their cycle of growth and drug release. On their own, they reduced tumor growth slightly, but when combined with the chemotherapy drug 5-fluorouracil, often used to treat liver cancer, they achieved a dramatic reduction in tumor size — much more extensive than if the drug was used on its own. This approach is well suited to liver tumors because bacteria taken orally have high exposure there, Bhatia says. “If you want to treat tumors outside the gut or liver with this strategy, then you would need to give a higher dose, inject them directly into the tumor, or add additional homing strategies,” she says. In previous studies, the researchers found that engineered bacteria that escape from the liver are effectively cleared by the immune system, and that they tend to thrive only in tumor environments, which should help to minimize any potential side effects. Martin Fussenegger, a professor of biotechnology and bioengineering at ETH Zurich, calls the new approach “unconventional” and “highly promising.” “This is a fascinating, refreshing, and beautiful concept,” says Fussenegger, who was not involved in the study. “In a world of mainstream cancer therapy concepts with often limited success, new therapy strategies are badly needed.” The researchers are now working on programming the bacteria to deliver other types of lethal cargo. They also plan to investigate which combinations of bacterial strains and tumor-targeting circuits would be the most effective against different types of tumors. The study was funded by the San Diego Center for Systems Biology, the National Institute of General Medical Sciences, the Ludwig Center for Molecular Oncology at MIT, an Amar G. Bose Research Grant, the Howard Hughes Medical Institute, a Koch Institute Support Grant from the National Cancer Institute, and a Core Center Grant from the National Institute of Environmental Health Sciences. (Comment on this)
1:00p	First atmospheric study of Earth-sized exoplanets reveals rocky worlds On May 2, scientists from MIT, the University of Liège, and elsewhere announced they had discovered a planetary system, a mere 40 light years from Earth, that hosts three potentially habitable, Earth-sized worlds. Judging from the size and temperature of the planets, the researchers determined that regions of each planet may be suitable for life. Now, in a paper published today in Nature, that same group reports that the two innermost planets in the system are primarily rocky, unlike gas giants such as Jupiter. The findings further strengthen the case that these planets may indeed be habitable. The researchers also determined that the atmospheres of both planets are likely not large and diffuse, like that of the Jupiter, but instead compact, similar to the atmospheres of Earth, Venus, and Mars. The scientists, led by first author Julien de Wit, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences, came to their conclusion after making a preliminary screening of the planets’ atmospheres, just days after announcing the discovery of the planetary system. On May 4, the team pointed NASA’s Hubble Space Telescope at the system’s star, TRAPPIST-1, to catch a rare event: a double transit, the moment when two planets almost simultaneously pass in front of their star. The researchers realized the planets would transit just two weeks before the event, thanks to refined estimates of the planets’ orbital configuration, made by NASA’s Spitzer Space Telescope, which had already started to observe the TRAPPIST-1 system. “We thought, maybe we could see if people at Hubble would give us time to do this observation, so we wrote the proposal in less than 24 hours, sent it out, and it was reviewed immediately,” de Wit recalls. “Now for the first time we have spectroscopic observations of a double transit, which allows us to get insight on the atmosphere of both planets at the same time.” Using Hubble, the team recorded a combined transmission spectrum of TRAPPIST-1b and c, meaning that as first one planet then the other crossed in front of the star, they were able to measure the changes in wavelength as the amount of starlight dipped with each transit. “The data turned out to be pristine, absolutely perfect, and the observations were the best that we could have expected,” de Wit says. “The force was certainly with us.” Courtesy of NASA/ESA/STScl A rocky sign The dips in starlight were observed over a narrow range of wavelengths that turned out not to vary much over that range. If the dips had varied significantly, de Wit says, such a signal would have demonstrated the planets have light, large, and puffy atmospheres, similar to that of the gas giant Jupiter. But that’s not the case. Instead, the data suggest that both transiting planets have more compact atmospheres, similar to those of rocky planets such as Earth, Venus, and Mars. “Now we can say that these planets are rocky. Now the question is, what kind of atmosphere do they have?” de Wit says. “The plausible scenarios include something like Venus, with high, thick clouds and an atmosphere dominated by carbon dioxide, or an Earth-like atmosphere dominated by nitrogen and oxygen, or even something like Mars with a depleted atmosphere. The next step is to try to disentangle all these possible scenarios that exist for these terrestrial planets.” “A rocky surface is a great start for a habitable planet, but any life on the TRAPPIST-1 planets is likely to have a much harder time than life on Earth,” says Joanna Barstow, an astrophysicist at University College London, who was not involved with the research. As the planets orbit very close to their star, Barstow says that may mean the radiation coming off the star may strip their atmospheres away entirely, making it extremely difficult for organisms to thrive, particularly as both planets are tidally locked, meaning they have permanent day and night sides. “Of course, our ideas of habitability are very narrow because we only have one planet to look at so far, and life might well surprise us by flourishing in what we think of as unlikely conditions,” Barstow says.  More eyes on the sky The scientists are now working to establish more telescopes on the ground to probe this planetary system further, as well as to discover other similar systems. The planetary system’s star, TRAPPIST-1, is known as an ultracool dwarf star, a type of star that is typically much cooler than the sun, emitting radiation in the infrared rather than the visible spectrum. De Wit’s colleagues from the University of Liège came up with the idea to look for planets around such stars, as they are much fainter than typical stars and their starlight would not overpower the signal from planets themselves. The researchers discovered the TRAPPIST-1 planetary system using TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope), a new kind of ground telescope designed to survey the sky in infrared. TRAPPIST was built as a 60-centimeter prototype to monitor the 70 brightest dwarf stars in the southern sky. Now, the researchers have formed a consortium, called SPECULOOS (Search for habitable Planets Eclipsing ULtra-cOOl Stars), and are building four larger versions of the telescope in Chile, to focus on the brightest ultracool dwarf stars in the skies over the southern hemisphere. The researchers are also trying to raise money to build telescopes in the northern sky. “Each telescope is about $400,000 — about the price of an apartment in Cambridge,” de Wit says. If the scientists can train more TRAPPIST-like telescopes on the skies, de Wit says, the telescopes may serve as relatively affordable “prescreening tools.” That is, scientists may use them to identify candidate planets that just might be habitable, then follow up with more detailed observations using powerful telescopes such as Hubble and NASA’s James Webb Telescope, which is scheduled to launch in October 2018. “With more observations using Hubble, and further down the road with James Webb, we can know not only what kind of atmosphere planets like TRAPPIST-1 have, but also what is within these atmospheres,” de Wit says. “And that’s very exciting.” This research was supported in part by NASA/Space Telescope Science Institute. (Comment on this)

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