Bowdoin College is a private liberal arts college located in the coastal Maine town of Brunswick. Founded in 1794, the college currently enrolls 1,839 students, and has been coeducational since 1971. Bowdoin offers 33 majors and 4 additional minors, and has a student-faculty ratio of 9:1. Famous alumni include Nathaniel Hawthorne, Henry Wadsworth Longfellow, Franklin Pierce, and Joshua Chamberlain. Bowdoin has an acceptance rate of 14.5% and was listed as the fourth-best liberal arts college in the U.S. in the 2014 U.S. News & World Report rankings.Bowdoin is located on the shores of Casco Bay and the Androscoggin River, 12 miles north of Freeport, Maine, and 28 miles north of Portland, Maine. In addition to its Brunswick campus, Bowdoin also owns a 118-acre coastal studies center on Orr's Island and a 200-acre scientific field station on Kent Island in the Bay of Fundy. Wikipedia.
Naculich S.G.,Bowdoin College
Journal of High Energy Physics | Year: 2014
Abstract: We generalize the scattering equations to include both massless and massive particles. We construct an expression for the tree-level n-point amplitude with n − 2 gluons or gravitons and a pair of massive scalars in arbitrary spacetime dimension as a sum over the (n − 3)! solutions of the scattering equations, à la Cachazo, He, and Yuan. We derive the BCJ relations obeyed by these massive amplitudes. © 2014, The Author(s).
Naculich S.G.,Bowdoin College
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012
We derive constraints on the color-ordered amplitudes of the L-loop four-point function in SU(N) gauge theories that arise solely from the structure of the gauge group. These constraints generalize well-known group theory relations, such as U(1) decoupling identities, to all loop orders. © 2011 Elsevier B.V.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ARCTIC SOCIAL SCIENCES | Award Amount: 48.60K | Year: 2016
Recent warming has resulted in Arctic permafrost thaw, earlier spring sea ice melt, and later fall sea ice formation. As a result, important coastal archaeological sites that were once protected by ice are exposed to increased damage and even complete loss due to a combination of melting permafrost and wave erosion during the extended open water season. With this project the research team will investigate significant prehistoric and historic archaeological deposits at one such threatened site, Iita (Etah) in northwestern Greenland. Research since 2006 has documented rapid erosion of the site and revealed stratified deposits extending back 1000 years. These deposits represent two different cultural groups, the Dorset, who lived there between AD 1050 and 1200, and the Thule (ancestors of the contemporary Inuit) who moved into the area from their homeland in Alaska around 1200. The area around Iita is rich in marine and terrestrial resources, including millions of dovekies, which nest in nearby cliffs. The investigators expect to recover both artifacts and animal bones that will increase our understanding of the different ways in which these two groups used these resources. The research team may also be able to determine whether they occupied the area at the same time, and if so, how they interacted. The nature of contact between Dorset and Thule people, if it happened, is one of the enduring questions in Arctic prehistory. The stratified deposits at Iita provide a rare opportunity to investigate this question. The team will focus their work on areas of the site most prone to erosion, recovering data before it is lost forever.
A team of six researchers from Bowdoin, UC Davis, and the National Museum of Greenland will excavate at the site of Iita, Qaasuitsup Kommunia, Greenland. Due to increased ice-free periods in the stormy fall season the site is experiencing rapid erosion, documented over the course of work at this site between 2006 and 2012. Excavations in historic contexts in 2006 revealed a buried early Thule component at the site and hinted at earlier occupations. In 2012 testing by J. Darwent and H. Lange confirmed the presence of a minimum of three discrete stratigraphic levels dating to the Late Dorset period, each separated by sterile sand. These distinct occupation levels offer an unprecedented opportunity to study and compare well-defined relatively brief occupations, in contrast to the often-mixed surface and near-surface sites more commonly found. They offer the opportunity to learn about many aspects of Late Dorset Culture, from the importance of exploiting the massive dovekie colony, to their demise as the ancestors of the contemporary Inughuit moved into the area. The early Thule levels also present at the site offer the possibility of identifying the nature and extent of interaction (if any) between these two groups. In this remote location, evaluation, monitoring, and mitigation of changes due to erosion are difficult. This fieldwork will allow the research team to both continue monitoring and to partially mitigate impending loss of these significant cultural resources.
Agency: NSF | Branch: Continuing grant | Program: | Phase: Physiolg Mechansms&Biomechancs | Award Amount: 298.56K | Year: 2016
All complex organisms are composed of cells that must bind to and communicate with each other, and all cells are surrounded by an extra-cellular matrix that provides some of these abilities. In plants, the extracellular matrix is termed the cell wall, and is partially composed of the carbohydrates cellulose and pectin. Several cell surface proteins act as sensors or receptors for the state of the cell wall, monitoring its integrity and composition. The Wall Associated Kinases (WAKs) are cell surface receptors that bind to the pectin in the cell wall, and regulate cell enlargement. WAKs are also activated by fragmented pectins generated by pathogens, mechanical stress and perhaps by normal developmental changes. The experiments that will be conducted during this project will begin to help in understanding the mechanism by which WAKs can distinguish and respond to different types of pectin in the cell wall, and thereby how plants sense the state of their cell wall, essential for their growth and development. This work will be carried out at a small liberal arts college where the focus is on undergraduate education and research. Students receive a thorough training in experimental science through work in this project, and a significant portion go on to graduate and professional school. The PI also incorporates many aspects of plant cell biology and genetics from his lab into the core cell biology and genetics lab course at the scientists institution, and is involved in courses for underprepared students in the sciences.
The cell walls of angiosperms are composed of a complex arrangement of cellulose, hemicellulose and pectin. The pectins can be selectively and locally modified to be cross-linked into a structural network that can have dramatic effects on cell enlargement. Localized digestion by plant secreted polygalacturonases can also modify the pectin network by loosening the cell wall to permit directional expansion of cells. Numerous pathogens and mechanical disruptions fragment pectin, often leading to a plant stress response. This project involves the Wall Associated Kinases (WAKs) that bind to both long polymers of cross-linked pectin and to pathogen and damage induced pectin fragments, or oligo-galacturonides (OGs). WAKs bound to native polymers are required for normal cell expansion, but bind newly generated OGs with higher affinity, and subsequently activate a distinct stress response pathway. This project will characterize receptor like kinases, cytoplasmic kinases, and potential scaffolding proteins that are phosphorylated upon OG treatment of Arabidopsis. The role of each of the 5 individual WAK isoforms, clustered in one 30 kb locus in Arabidopsis will be genetically dissected using a new CRISPR/Cas9 based WAK deletion mutant. The puzzle is how one receptor type can distinguish and respond in different ways to different types of pectin, during development and the response to environmental disturbance. The goal is to understand if this is achieved through different WAKs each binding different pectins, and in combination with different co-receptors and ligands to activate alternate pathways.
Agency: NSF | Branch: Standard Grant | Program: | Phase: MAJOR RESEARCH INSTRUMENTATION | Award Amount: 437.88K | Year: 2015
This Major Research Instrumentation award supports the acquisition of a modern scanning electron microscope (SEM) equipped with an array of detectors that image samples and collect quantitative data on chemical compositions and crystal orientations. This highly versatile instrument will support and advance research in geology, oceanography, chemistry and archaeology at Bowdoin College, a liberal arts college in Maine. Examples of some of the diverse research that will be advanced by the SEM relate to the movement of Earth?s tectonic plates, the evolution and eruptions of supervolcanoes, factors affecting clamshell strength, the origin of Arctic artefacts, and the metallurgy of ancient Greco-Roman coins. The new instrumentation also will facilitate undergraduate research training at the College. Undergraduate students will use the SEM in multiple courses as well as during independent-study and summer research projects. These research projects will train students to apply modern analytical techniques to original research questions in Earth Science and will enhance the infrastructure for research across disciplines at the College. Additionally, the PIs will incorporate SEM-based research into a pre-matriculation outreach program at the College that provides underrepresented undergraduate students with a multi-day immersion program in science. Images and data collected by undergraduates and researchers with the SEM will be used to increase public scientific literacy through an annual exhibition at Bowdoin College and through web page features.
The SEM will be equipped with a backscattered electron (BSE) detector, cathodoluminescence (CL) detector, energy dispersive spectrometer (EDS), and a fully integrated electron backscatter diffraction (EBSD) system. Using these detectors, the research activities will leverage the high spatial resolution of the SEM and the ability to simultaneously acquire multiple datasets (i.e. geochemistry and crystal orientation) to investigate a variety of mineralogic, petrologic, and tectonic questions. Example applications include: 1) characterization of accessory minerals that record pressure-temperature-time constraints, 2) crystal orientation measurements to infer the mechanics of plutonic-volcanic, deformation, and crystal growth processes, 3) determination of compositional zoning and/or domains in rock-forming minerals to track changes in pressure, temperature, deformation, and composition, 4) characterization of deformation microstructures, 5) measurement of the impact of freshwater flow on the carbonate chemistry of estuarine environments, 6) identification of growth bands in deep sea corals, 7) determination of the origin of artefacts in the Arctic, and 8) evaluation of metallurgy and the circulation routes of ancient coins. The instrumentation facilitates innovative research that meaningfully involves professors, collaborators, students, and community partners and expands the breadth of scientific inquiry possible at Bowdoin College.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ENVIRONMENTAL ENGINEERING | Award Amount: 63.76K | Year: 2016
1604305 / 1603755 / 1604165
MacKay / Vasudevan / Johnston
The last decade has witnessed a radical shift in the prioritization of environmental contaminants. No longer is our primary concern non-polar compounds that persist and bioaccumulate, but the inventory of organic contaminants has expanded greatly to include many polar and ionic compounds with potential adverse ecotoxicological effects. This study offers an innovative approach to adapt computational chemical tools to the prediction of organic ligand sorption to metal oxides.
The proposed approach represents a transformative advance in the quantitative a priori prediction of sorption coefficients for polar and ionic compounds in the environment. The integration of molecular dynamics calculations to obtain quantum mechanics measures of van der Waals, electrostatic energies and solvation effects overcomes the challenge of deconvoluting coupled structure effects from experimental measures of sorption energies alone, is at the current state of the science. Furthermore, other related sorption problems provide opportunity to expand Linear Interaction Energy approximation techniques because environmental sorbent characteristics are more generalizable than protein binding site characteristics. The overarching hypothesis of the project is: that changes in organic ligand structure by the addition/removal of non-ligand group substituents impart regular changes in sorption free energy as a result of coupled hydrophobic, electronic and proximity (i.e., steric and chelation) effects that are in turn mediated by solvent effects. The ultimate goal is to quantitatively describe organic ligand sorption to oxides as a function of specific sorbate structure criteria. A novel approach is used to identify structural criteria by bridging well-established experimental techniques with innovations in computationally relevant environmental surface chemistry, and by using the representative soil oxide, goethite. Task 1: The goethite force field will be fine-tuned using density functional theory to determine accurate compound conformations for a library of test sorbates. The chosen library includes sorbates with incremental changes in structure that allow us to identify the influence of specific ligand and non-ligand structural moieties. Computational efforts will be validated by infrared spectra to delineate binding mechanisms and transmission electron microscopy to identify relevant crystal faces. Quantum mechanics calculations will be used to calculate free energies of the inner sphere complexation reaction. Task 2: Experimental measures of sorption energies, infrared spectra and goethite measures will be obtained for test sorbates sorbed to high purity goethite. Task 3: The Linear Interaction Energy approximation will be used with molecular dynamics simulations and Task 1 force fields and inner sphere binding energies to calculate van der Waals and electrostatic contributions to overall sorption free energies. Linear Interaction Energy offers significant reductions in computational cost because molecular dynamics simulations are conducted only for the bound and unbound states. van der Waals and electrostatic energies will be regressed against experimental measures of sorption free energies to generate a predictive model for sorption coefficients. Findings from Tasks 1-3 will be integrated to identify how specific structural features can be linked to regular changes in van der Waals and electrostatic energies, thereby indicating structure-sorption relationships relevant to quantitative models. The PIs will mentor graduate and undergraduate researchers through the processes of experimental design, manuscript preparation and national professional society presentations. They will also work closely with high school students and teachers to introduce sorption concepts into public education with hands-on demonstration modules of everyday applications: home drinking water treatment and pesticide application. The PIs will continue their committed record of engaging student researchers from groups underrepresented in the sciences and engineering.
Agency: NSF | Branch: Standard Grant | Program: | Phase: FIELD STATIONS | Award Amount: 214.36K | Year: 2015
The Bowdoin College Coastal Studies Center (http://www.bowdoin.edu/coastal-studies-center/) is awarded a grant to expand the capabilities of an existing flowing seawater system so that climate variables can be independently manipulated in experimental aquaria. The Coastal Studies Center (CSC) on Orrs Island in mid-Coast Maine, is an educational and research laboratory serving Bowdoin College and visiting students and researchers. The CSC has a sentinel position at the southern boundary of the Gulf of Maine, a cold-water boundary that is moving northward as the Earths climate warms. Further, the once highly productive Gulf of Maine faces other synergistic impacts including overfishing and invasive species that are changing the structure and function of kelp forests, the rocky intertidal, seagrass beds, and salt marshes. While several research-focused marine laboratories rim the Gulf of Maine, the CSC is a unique RUI focused center that is focused on facilitating undergraduate engagement on the problems of a rapidly changing ocean. This project improves the RUI capabilities of Bowdoin College, which has significantly increased female and minority enrollment over the last ten years. The new experimental seawater capabilities are also likely to attract new visiting students and faculty, expanding the CSC research community. Finally, the improvements will allow increased experimentation and monitoring of estuarine systems. Estuaries support high biological productivity, yet they also experience stronger and more variable impacts of ocean acidity than the open ocean due to the reduced buffering capacity of freshwater inputs and high biological contributions of carbon dioxide. A new cluster of sensors will sample key climate change variables (including crucial pCO2) in Harpswell Sound and stream this data to Internet portals year round, providing a much-needed estuarine node in the Gulf of Maine.
The project has two major elements: 1. building four experimental seawater modules that will independently control temperature, oxygen levels, pH, and sterilize effluent; and 2. constructing a pier-mounted instrument array to continuously monitor climatic variables. Element 1 includes a seawater cooling system that combines an external centralized chilling unit with four independent chilled water loops (modules) that can cool 400 gallons of seawater from summer ambient temperatures to 4 degrees Celsius. Additionally, each module will be fitted with the plumbing, controls, and sensors to manipulate dissolved oxygen levels and pH via addition of nitrogen and carbon dioxide gasses respectively. An inline UV filter system will be added for experimental applications that culture non-native organisms and require effluent sterilization. Element 2 will install a pier-based environmental monitoring platform, that will stream temperature, salinity, pH, and pCO2 data to a global research community 365 days a year. This new monitoring location in Harpswell Sound will provide key environmental data on how estuarine marine systems are responding to climate change, and provide essential data for parameterizing climate change experiments.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ACTIVATION | Award Amount: 430.00K | Year: 2014
The overarching goal of this project is to understand the processes that underlie variability in behavior. Specifically, the project will focus on variability in the responses of neuronal networks generating the activity that controls rhythmic movements to one hormone. This project will utilize the lobster cardiac neuromuscular system, a simple model for understanding this phenomenon. In this system, some hearts respond to the hormone allatostatin-C with increased contraction force, while others respond by decreasing contraction force. The project is multi-disciplinary, using physiological, molecular and biochemical approaches. Experiments will include recording changes in activity of the lobster heart when exposed to the hormone, using molecular biological techniques to determine the genes that contribute to the differential responses to the hormone in different animals, and analyzing proteins within the heart to determine how they differ among animals that respond differently to the hormone. This project is a collaboration between researchers at Bowdoin College (Brunswick, Maine) and the University of Hawaii at Manoa (Honolulu). It will train undergraduates, including underrepresented minority students, at both institutions in a wide variety of chemical, molecular and physiological techniques. It will provide interdisciplinary training and will introduce undergraduates to the importance of examining scientific questions from multiple perspectives. The molecular components of the project will also provide resources that can be used by other scientists to address additional issues in lobster biology, including the origin and physiological consequences of shell disease.
To determine the mechanisms and triggers that underlie the variability in the responses of neuronal networks to modulators, this project will examine a simple pattern generator, the lobster cardiac ganglion. This project will combine transcriptomics and physiology to look for differences in gene expression that correlate with differential responses to the peptide hormone, allatostatin-C. At the same time, the project will ask whether these differences may be triggered by changes related to the molt cycle. The project, which will use Illumina sequencing, will assemble de novo transcriptomes from lobster tissues. These transcriptomes will provide references onto which RNA-Seq data from lobsters that respond differentially to allatostatin-C in physiological experiments will be mapped to determine changes in gene expression. The investigation will target specific genes and will use a genome-wide assessment to look for additional changes. The project will also use mass spectrometry to ask whether specific proteins show different post-translational modifications in lobster hearts that respond differentially to the neuropeptide.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ARCTIC SOCIAL SCIENCES | Award Amount: 12.82K | Year: 2016
This is a small RAPID award for PI Susan Kaplan to take advantage of a Parks Canada vessel and polar bear monitors free of charge for two weeks fieldwork in northern Labrador, Canada. This project will be a stability assessment of a Middle Dorset (800 CE to 1,000 CE; CE meaning Common Era or the equivalent of 1,216 years ago to 1,016 years ago) archaeological site (Avayalik-1) 25 miles south of the tip of Labrador.
Worldwide archaeological heritage is under threat from environmental change; in the Arctic this is manifested as sea level rise and the accompanying storm surges eating way at coastal sites. As in other places in the Arctic, Avayalik-1 permafrost is melting causing changes in hydrology and the deterioration of fragile organic artifacts and faunal remains. This investigation will assess the vulnerability of archaeological sites in permafrost, which will contribute to discussions on how to assess, monitor, and preserve such sites. This information is of great interest to the scientific community, culture resource managers but also to the indigenous residents who are in many cases the decedents of the original occupants.
Avayalik-1 is a scientifically unique site of Middle Dorset (pre Thule culture, the ancestors of modern Inuit people). Avayalik-1, last investigated in 1978, yielded organic artifacts and faunal remains unsurpassed in quantity and preservation by any other Labrador Middle Dorset sites due to the fact the ground was permanently frozen. However, with the current state of the Arctic and the rapidly thawing permafrost, many Arctic heritage sites thought for decades to be not endangered are now under threat. Avayalik-1 is such a site.
This important project will assist archaeologists and culture heritage managers in determining whether the Avayalik-1 site is endangered, which would signal a potential loss of a critical Paleo-Inuit environmental and cultural record. In addition, new archaeometric and data techniques will be applied to the soil samples taken from the site, techniques not available in 1978 when the site was last studied. This data will help in assessing the full potential of the site for contributing to our understanding of how people have adapted to life in challenging environment sand how the ecology of the maritime North Atlantic has changed over time.
Agency: NSF | Branch: Standard Grant | Program: | Phase: APPLIED MATHEMATICS | Award Amount: 98.60K | Year: 2016
This project aims to develop analytical, computational, and experimental tools for the study of a particular class of lattice networks. Of particular interest in this research are the dynamics of localization and time-periodicity, which can be exploited for a variety of applications including vibration energy harvesting. Through the geometry of the network and the nonlinear nature of the connecting elements, extremely rich dynamics can be observed and verified by experimental data provided by collaborations with engineering laboratories. The results could be used to develop broadband resonators that are powered through ambient vibrations, with the goal of significantly reducing battery usage.
The models under study in this project have the form of a two-dimensional nonlinear coupled oscillator, where the coupling is described by a power-law. Closed-form analytical expressions for solutions of these equations are not available, and thus the theoretical study of the system will concern analytical approximations and numerical computation. Multiscale methods will be used to derive modulation equations to describe spatially localized and time-periodic solutions, and error bounds for these approximations will be explored. In parametric regions where the derived analytical approximations are not valid, numerical computations will be employed. Three case examples are considered for experimental realizations: granular crystals, repelling magnets, and origami unit cells. An energy harvesting concept based on a magnetic lattice network will be designed, optimized, implemented, and benchmarked.