Report of Science at Williams College 2016-2017 A record of the professional and academic activites of faculty and students in the natural sciences Williamstown, Massachusetts Front Cover Image: Luminescent molecules (background) and terbium and europium complexes (foreground) prepared in the lab of Patrick Barber of the chemistry department. My research interests lie in the design, development, and application of functional materials made from lanthanide ion complexes for imaging in environmental and biological systems. The lanthanides have long been studied for their interesting luminescent and magnetic properties. Through the use of these well- known properties, lanthanide ion complexes are excellent choices for use as probes to monitor living and non-living systems. The Science Executive Committee wishes to express its gratitude to the extensive efforts of all the science depart- mental administrative assistants in preparing contributions for this publication. Editor: Norman Bell, Science Coordinator This document is printed on recycled paper. III Williams College admits men and women of any background to all the rights, privileges, programs and activities generally accorded or made available to students at the College. It does not discriminate on the basis of race, color, religion, creed, sexual orientation, or national ethnic origin in administration of its educational policies, scholarship and loan programs, and athletic and other college administered programs. The College does not discriminate on the basis of sex in violation of the Title IX of the Education Amendments of 1973, or the regulations thereunder, in the education programs or activities which it operates, including employment therein. The College does not discrim- inate on the basis of handicap in violation of Section 504 of the Rehabilitation Act 1973, or the regulations there- under, in admission or access to its programs and activities. Inquiries concerning the College’s non-discrimination policies may be referred to the Dean of the College, Hopkins Hall, Williamstown, MA 01267. IV Table of Contents The Sciences at Williams College 1 Major Science Center Funding 2 Major Programs in the Sciences 3 Winter Study 2017 Offerings 7 The Science Center 10 Student Summer Science Research 2017 11 2017 Summer Science Research Funding Sources 12 Summer Science Students and their Faculty Advisors 2017 13 Summer Science Research Poster Session: August 11, 2017 15 Summer Science Research Colloquia 2017 17 Pre-First Year Summer Science Program 18 Pre-First Year Summer Science Program Participants 2017 19 Summer Science Lab Program 20 Williams College Sigma Xi Chapter and 2017 Inductees 21 Teaching to Learn 22 In Memoriam 23 Department News Astronomy 24 Biology 28 Chemistry 36 Computer Science 44 Geosciences 50 Mathematics and Statistics 58 Neuroscience 77 Physics 79 Psychology 86 Abstracts from Student Theses 94 Abstracts from Faculty and Student Publications 125 V The Sciences at Williams College Students learn science best by doing science; that is by bers, after being nominated by faculty and reviewed by formulating and testing their own hypotheses, using members of the Williams College chapter of Sigma Xi. methods capable of producing convincing evidence. Williams College has become a leader in the training of This is true at the introductory level, where students be- future scientists with more than 50 students going on to come interested in further study by encountering science Ph.D. programs in science each year. As a result of this as discovery rather than rote facts. It is even more im- commitment, Williams has ranked first among predom- portant at advanced levels, where students are most like- inantly undergraduate institutions in students receiving ly to become interested in science careers by working as NSF pre-doctoral fellowships, averaging about 7 per fully involved junior colleagues with professionally ac- year over the past ten years. We attribute this success tive faculty on research projects that explore new scien- to an energetic faculty and staff dedicated to providing tific ideas. The ability to conduct cutting-edge research an excellent educational experience and to the many re- at Williams helps to attract talented scientists as facul- search opportunities available to Williams students at ty and keeps them at the forefront of their disciplines, both advanced and introductory levels. which in turn allows faculty to bring the excitement of It has long been recognized that a positive undergrad- their research work to their teaching and course devel- uate research experience is the single most important opment at all levels. The College has invested deeply in inspiration for future scientists. As documented in this this ambitious program of research and teaching through report, more than 250 students were engaged in science research funding, modern laboratory space, shared in- research with Williams faculty this year. Many students strumentation, and technical support. The relatively conducted independent research projects during the ac- large number of faculty in all the science departments ademic year with 91 completing theses and 171 were promotes breadth and depth in both research activities engaged in full-time research with Williams science and curricular scope. faculty during the summer of 2016. Dozens of Williams In 2000, a $47 million science facility was completed students participated in conferences where they present- to unify all science departments in a single complex ed the results of their research, and at least 50 students surrounding a central science library. Our model of the co-authored publications in peer-reviewed journals in entire science division as a cohesive programmatic unit the past academic year. has flourished. Construction has now begun on a new Concurrent with the increased student involvement science center addition which will become the founda- in science, Williams has attracted talented and vibrant tion for science at Williams in the 21st century. Funds science faculty engaged in competitive research and for major equipment, for individual student-faculty dedicated to teaching undergraduates. As a result, the research projects, and for stipend support of students number of external grants awarded to support faculty doing research with faculty are coordinated on a divi- research or curricular innovation puts Williams near sion-wide basis by the Science Center Director, the Sci- the top of all non-Ph.D-granting institutions. In the past ence Executive Committee and the Divisional Research five years, Williams faculty members were awarded 39 Funding Committee. By working together, we are able NSF grants totaling $5,786,152 and 3 NIH grants total- to share not only facilities and equipment, but also ideas ing $1,026,639. The large number of individual faculty and enthusiasm, and so provide a “critical mass” of ac- grants, together with recent grants from the Sherman tivity that might not be possible within an individual de- Fairchild Foundation, the Clare Boothe Luce Founda- partment at a small institution. tion, endowed funds from the Kresge Foundation, the The class of 2017 had 525 graduates, with 255 majors in Keck Foundation, and other sources, has enabled us to a science or mathematics discipline. Approximately 25% purchase and maintain state-of-the-art equipment for of students in 2016 have expressed interest in careers in teaching and research. Emphasizing close student-fac- scientific research. The quality of the College’s science ulty interactions, the opportunities in undergraduate programs has nurtured this interest and this year 67 stu- science education at Williams are exciting, diverse, and dents were inducted into Sigma Xi as associate mem- forward-looking. 1 Major Science Center Funding Kresge Foundation Equipment Grant or institutes. Williams was awarded a large grant from the Kresge Clare Boothe Luce Research Scholarships Foundation in 1990 to replace and update major items Funded by the Henry Luce Foundation, the Clare Boothe of scientific equipment and instrumentation. This three- Luce research scholars grant increases the number of part grant is used to purchase new equipment, to support female students at Williams who declare majors in the maintenance contracts and the repair of existing instru- physical sciences (astrophysics, computer science, geo- ments, and also to support technical staff members who sciences, mathematics/statistics, and physics) and in- oversee the instruments. One aspect of the grant is that creases the proportion of women in these fields conduct- the College sets aside endowment funds for the depre- ing honors thesis research and pursuing doctoral degrees ciation and eventual replacement of items purchased and careers in science. The Clare Boothe Luce research under the grant. Through this grant the college has pur- grant supports cohorts of eight women each year for chased and maintains a 24-inch optical telescope, a gas three years with funding for summer research stipends, chromatograph mass spectrometer, a transmission elec- research supplies and equipment, and attendance at pro- tron microscope, a UV/Vis/NIR spectrophotometer, and fessional conferences. Williams College supports the an x-ray diffraction instrument. In recent years, Kresge Clare Boothe Luce scholars program with funds for a endowment funds were used to replace earlier models of second year of honors theses related research and funds a scanning electron microscope, a nuclear magnetic res- programmatic