Report of Science at Williams College 2015-2016 A Record of the Professional and Academic Activities of Faculty and Students in the Natural Sciences Williamstown, Massachusetts Front Cover Image: Thin section Gigapan photomicrograph of a garnet, chloritoid, chlorite schist from Jamaica, Vermont. The field of view is approximately 20 by 30 mm, and parallel polarized light was used for illumination. The photo was created with the automated thin section imaging system at Williams College developed by Paul Karabinos, Michael Taylor, and Larry George. The automated microscope stage moves by precise increments to capture hundreds of individual high-magnification photographs, which are then stitched together to create a 1.89 Gigapixel image. The Gigapan image makes it possible to view an entire thin section at once or to zoom into small areas to view details at high magnification. The gray area is a large garnet crystal that overgrew chloritoid and chlorite grains. The parallel alignment of the inclusions formed during an episode of deformation before the garnet grew. After garnet growth, a later deformation event created micro-folds in the matrix surrounding the garnet. The mineral inclusions in garnet escaped the younger deformation because they were sheltered by the rigid crystal. Thin sections are made from slices of rock that are 40 mm long, 25 mm wide, and 30 microns thick. Polarized light passes through optically anisotropic minerals and creates interference colors diagnostic of different minerals. Mineral textures in thin sections record information about the formation and history of rocks. You can view Professor Karabinos’ entire Gigapan collection http://gigapan.com/profiles/Stretchedpebble/ galleries The Science Executive Committe wishes to express its gratitude to the extensive efforts of all of the science departmental executive assistants in preparing this publication. Editor: Norman Bell Coordinator of Science Facilities 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 discriminate on the basis of handicap in violation of Section 504 of the Rehabilitation Act 1973, or the regulations thereunder, 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 2016 Offerings 8 The Science Center 13 2016 Student Summer Science Research 13 Funding Sources 14 Students and their Faculty Advisors 15 August 12, 2016 Poster Session 19 Colloquia 22 Pre-First Year Summer Science Program 23 Summer Science Lab Program 25 Sigma Xi 26 Science Lunch Colloquia 27 Teaching to Learn 28 Department News Astronomy 29 Biology 34 Chemistry 42 Computer Science 53 Geosciences 60 Mathematics and Statistics 68 Neuroscience 85 Physics 88 Psychology 95 Abstracts from Student Theses 105 Abstracts from Publications and Presentations 133 V Ground has been broken on the new science building south of the Morley Science Labs (photos taken August and October 2016). This building will primarily house research labs, offices, and support space for the Biology, Chemistry, and Physics departments. Construction is expected to be complete by Spring of 2018. The Sciences at Williams College Students learn science best by doing it — when Xi as associate members, after being nominated by they formulate and test their own hypotheses, using faculty and reviewed by members of the Williams methods capable of producing convincing evidence. College chapter of Sigma Xi. Williams College has This is true at the introductory level, where students become a leader in the training of future scientists with become interested in further study by encountering more than 50 students going on to Ph.D. programs in science as discovery rather than rote facts. It is even science each year. As a result of this commitment, more important at advanced levels, where students are Williams has ranked first among predominantly most likely to become interested in science careers undergraduate institutions in students receiving NSF by working as fully involved junior colleagues with pre-doctoral fellowships, averaging about 7 per year professionally active faculty on research projects that over the past ten years. We attribute this success to explore new scientific ideas. The ability to conduct an energetic faculty and staff dedicated to providing cutting-edge research at Williams helps to attract an excellent educational experience and to the many talented scientists as faculty and keeps them at the research opportunities available to Williams students forefront of their disciplines, which in turn allows at both advanced and introductory levels. faculty to bring the excitement of their research It has long been recognized that a positive work to their teaching and course development at undergraduate research experience is the single all levels. The College has invested deeply in this most important inspiration for future scientists. As ambitious program of research and teaching through documented in this report, more than 250 students were research funding, modern laboratory space, shared engaged in science research with Williams faculty this instrumentation, and technical support. The relatively year. Many students conducted independent research large number of faculty in all the science departments projects during the academic year with 81 completing promotes breadth and depth in both research activities theses and 193 were engaged in full-time research and curricular scope. with Williams science faculty during the summer In 2000, a $47 million science facility was completed of 2016. Dozens of Williams students participated to unify all science departments in a single complex in conferences where they presented the results of surrounding a central science library. Our model of their research, and at least 50 students co-authored the entire science division as a cohesive programmatic publications in peer-reviewed journals in the past unit has flourished. Construction has now begun on a academic year. new science center addition which will become the Concurrent with the increased student involvement in foundation for science at Williams in the 21st century. science, Williams has attracted talented and vibrant Funds for major equipment, for individual student- science faculty engaged in competitive research and faculty research projects, and for stipend support of dedicated to teaching undergraduates. As a result, the students doing research with faculty are coordinated number of external grants awarded to support faculty on a division-wide basis by the Science Center research or curricular innovation puts Williams near Director, the Science Executive Committee and the the top of all non-Ph.D-granting institutions. In Divisional Research Funding Committee. By working the past five years, Williams faculty members were together, we are able to share not only facilities and awarded 37 NSF grants totaling $5,301,975 and 3 equipment, but also ideas and enthusiasm, and so NIH grants totaling $1,026,639. The large number of provide a “critical mass” of activity that might not be individual faculty grants, together with recent grants possible within an individual department at a small from the Sherman Fairchild Foundation, the Clare institution. Boothe Luce Foundation, endowed funds from the The class of 2016 had 536 graduates, with 263 majors Kresge Foundation, the Keck Foundation, and other in a science or mathematics discipline. Approximately sources, has enabled us to purchase and maintain 25% of students in 2016 have expressed interest in state-of-the-art equipment for teaching and research. careers in scientific research. The quality of the Emphasizing close student-faculty interactions, the College’s science programs has nurtured this interest opportunities in undergraduate science education at and this year 56 students were inducted into Sigma Williams are exciting, diverse, and forward-looking. 1 Major Science Center Funding Kresge Foundation Equipment Grant Clare Boothe Luce Research Scholarships Williams was awarded a large grant from the Kresge Funded by the Henry Luce Foundation, the Clare Foundation in 1990 to replace and update major items Boothe Luce research scholars grant increases the of scientific equipment and instrumentation. This number of female students at Williams who declare three-part grant is used to purchase new equipment, majors in the physical sciences (astrophysics, to support maintenance contracts and the repair of computer science, geosciences, mathematics/ existing instruments, and also to support technical staff statistics, and physics) and increases the proportion members who oversee the instruments. One aspect of of women