Showing 151 - 200 of 681 Items
Postmemory’s Shadow Archives: Reshaping the Punctum in Asian Diaspora Poetry This record is embargoed.
Date: 2024-01-01
Creator: Hannah Kim
A Practical Study in Conducting Renaissance and Contemporary Choral Music During the COVID-19 Pandemic Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Emily M. Ha
Access: Access restricted to the Bowdoin Community
A Fatal Mistake or a Paradigm Shift? Noguchi Hideyo and the Global Reimagining of Yellow Fever
Date: 2025-01-01
Creator: Seth Gorelik
Access: Open access
Mythologisation, magnification, et modification : La Culture de la langue française
Date: 2025-01-01
Creator: Rachel Houston Scruby
Access: Open access
- Across three chapters, this thesis examines how the French language plays a vital role not only as a vehicle for communication but as an incarnation of culture, and how France makes sense of linguistic and cultural changes today through the lens of its long history. An analysis of historical documents from key moments in this history illuminates French’s central role as an instrument of power reliant on a prioritization of elegance and beauty, an equivalency between language and people based in a grand history, and a global influence. It shows how this history constructed the language as a political tool, capable of bolstering France’s global importance through “soft power.” This created not only the conditions for the imposition of French to combat fears of decline in military and political domains, but also a simultaneous conflict between the language as an expression of elegance and as a tool to be spread widely to assert the country’s dominance, particularly during the colonial period. Close examination of this long and intricate history illuminates our understanding of how France currently works to reconcile its history with its present in a world where the French language is far more widely spoken than at any other period but is no longer the primary possession of France itself.
Examining Functional Roles for Anthocyanins in Plant Leaves Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2016-05-01
Creator: Benjamin M West
Access: Access restricted to the Bowdoin Community
Deciphering Policymaking—The Enigma of the 2003 Iraq War
Date: 2024-01-01
Creator: Chengkai Gu
Access: Open access
- This thesis examines the forces shaping the United States’ decision to initiate the 2003 Iraq War. It argues that while the Bush administration had vested interests in disarming Iraq to eliminate Saddam Hussein’s military threat and to secure stable global oil supplies, the decision-making process leading to the Iraq War was heavily influenced by domestic politics, such as bureaucratic bargaining, CIA intelligence collections, and interest group competition. In addition, individual-level factors, such as top officials’ personal beliefs and psychologies, also shaped the decision to intervene in Iraq. By explaining how strategic, domestic, and personal factors interacted to shape the decision to launch the Iraq War, my study underscores the impact of less obvious micro-level dynamics on international politics and the multi-layered nature of foreign policymaking.
Three Decades of Replicated Field Studies Reveal Eelgrass (Zostera marina) Inhibits Soft-shell Clam (Mya arenaria) Growth in Eastern Maine This record is embargoed.
- Embargo End Date: 2027-05-16
Date: 2024-01-01
Creator: Everett Horch
Access: Embargoed
Non-Naturalism and Naturalism in Mathematics, Morality, and Epistemology
Date: 2018-05-01
Creator: Nicholas DiStefano
Access: Open access
He Mauka Teitei, Ko Aoraki, The Loftiest of Mountains: The Names of Aotearoa’s Highest Peak and Beyond
Date: 2024-01-01
Creator: Joseph B. Lancia
Access: Open access
- My thesis discusses the cultural, political, and social dynamics of mountains with separate Indigenous and Western names and identities. Centering on Aoraki/Mount Cook—the highest peak in Aotearoa New Zealand—I integrate personal experiences as ethnographic data through narratives, mainly of my time hiking while studying abroad in New Zealand and during the two recent summers I spent exploring Rocky Mountain National Park in Colorado. Through its name, Aoraki/Mt. Cook maintains Indigenous Māori and Western perspectives: Aoraki being a Māori atua (god) and Captain James Cook being a significant colonial figure in the Pacific. The slash upholds both identities while ensuring that they exist together. These dynamics are explored in depth and extended to mountains in places including Colorado, Alaska, and Australia. While discussing Rocky I rely heavily on Oliver Toll’s Arapaho Names & Trails (2003) which contains a substantial collection of Arapaho knowledge of the area and I give strong attention to Nesótaieux (Longs Peak and Mount Meeker). Additionally, I look at Mount Blue Sky, Denali, and Uluru/Ayers Rock to discuss mountains that have had formal name changes and how legacies are maintained through toponyms. With discussing varying identities and perceptions of each example and the knowledge held in names I encourage readers to do research into local Indigenous knowledges to further their and others’ understandings of places. I emphasize the concepts of historical silences, the revealing of knowledge, and the importance of language to articulate that Indigenous knowledge might be difficult to find but is never truly lost.
Fall forward, spring back: Drivers of synchrony in the sea star crawl-bounce gait transition
Date: 2024-01-01
Creator: Brady R Nichols
Access: Open access
- The Froude number is the ratio of kinetic energy to gravitational potential energy used during locomotion and is often used to analyze gait transitions. Here, I compare and contrast the human walk-run gait transition, which occurs at a consistent Froude number of 1 because there exists a mechanical speed limit to walking, and the sea star crawl-bounce gait transition, which occurs around Froude numbers of 1*10^-3. In this thesis I investigate why sea stars exhibit two gaits despite lacking brains and moving at Froude numbers far below other known gait transitions, hypothesizing (1) that the crawl-bounce transition may be mechanical and thus still depends on the Froude number, and (2) that the crawl-bounce transition is best modeled gradually compared to the instantaneous human walk-run transition. Thirty sea stars were filmed and the resulting kinematic data is used here to inform thinking about the crawl-bounce transition. I first discuss damped driven harmonic motion of a single oscillator, but eventually turn to using coupled oscillators and deriving that a coupling constant between metronomes on a moving base is the Froude number, which is therefore relevant for the crawl-bounce transition. I lastly discuss a purely mathematical analogue of the crawl-bounce transition as a Hopf bifurcation in horizontal speed and vertical velocity phase space, which leads to a rough model with results qualitatively similar to observed kinematic data from films, and indicates that a gradual transition is in fact a good fit for the crawl-bounce transition.
Origin of Rhyolite from Magma Mush: Plutonic Lithics from the Ohakuri Ignimbrite, Taupō Volcanic Zone, New Zealand This record is embargoed.
- Embargo End Date: 2027-05-15
Date: 2024-01-01
Creator: Christine Reimer
Access: Embargoed
Policy Making, Decision Making, and Advocacy: The U.S. Asylum System Since 9/11
Date: 2024-01-01
Creator: Clara Jergins
Access: Open access
- Immigration justice advocates and immigration restrictionists alike are unhappy with the way that the U.S. asylum system functions. This project seeks to develop a better understanding of policy changes and the politicized influence of the president and executive authorities over the asylum system since 9/11—in particular, these individuals’ ability to implement their policy preferences through the hiring and instruction of Asylum Officers and Immigration Judges. Through case studies of nonprofit organizations, it identifies the key points in the asylum process where asylum has been restricted, and the ways in which these restrictions can be responded to. On the basis of these factors, this project identifies four key changes, made by Congress, through which the asylum system could be improved: the establishment of an Article I immigration court, encoded testimonial and credibility standards, universal representation, and an end to asylum seeker detention. These changes are asserted to depoliticize the asylum process and to create a stable asylum system in which those that should qualify for asylum do qualify.
DS-PSO: Particle Swarm Optimization with Dynamic and Static Topologies
Date: 2017-05-01
Creator: Dominick Sanchez
Access: Open access
- Particle Swarm Optimization (PSO) is often used for optimization problems due to its speed and relative simplicity. Unfortunately, like many optimization algorithms, PSO may potentially converge too early on local optima. Using multiple neighborhoods alleviates this problem to a certain extent, although premature convergence is still a concern. Using dynamic topologies, as opposed to static neighborhoods, can encourage exploration of the search space at the cost of exploitation. We propose a new version of PSO, Dynamic-Static PSO (DS-PSO) that assigns multiple neighborhoods to each particle. By using both dynamic and static topologies, DS-PSO encourages exploration, while also exploiting existing knowledge about the search space. While DS-PSO does not outperform other PSO variants on all benchmark functions we tested, its performance on several functions is substantially better than other variants.
Fitness and sex effects of a novel microsporidian parasite on its Daphnia host
Date: 2025-01-01
Creator: Gracie Scheve
Access: Open access
- Parasitism can influence host ecology and evolution in powerful ways, although the specific impacts on host fitness and life history may be context dependent and involve complex trade-offs. In this study, I investigated the effects of a novel microsporidian gut parasite on Daphnia ambigua, a freshwater zooplankton with a cyclical parthenogenetic life cycle. Combining extensive field sampling at Sewall Pond, Maine, with chronic exposure experiments in the lab, I assessed the parasite's impact on Daphnia fitness and propensity to shift from asexual to sexual reproduction. Field observations revealed a correlation between gut parasite prevalence and increased production of males and sexual females, independent of known sex inducers such as crowding, food limitation, and photoperiod. Lab experiments confirmed that chronic spore exposure significantly reduced Daphnia survival and reproductive output, particularly in clones previously naïve to this strain of the parasite. However, no induction of sex or male offspring was observed in response to parasite exposure under laboratory conditions. This suggests that more complex environmental interactions might be triggering sex in Daphnia. While sex provides the benefit of increased genetic diversity for future generations, I hypothesize that while Daphnia undergo sexual reproduction their ability to resist or tolerate parasite infection is diminished. Phylogenetic analyses indicate the parasite is closely related to the less virulent microsporidian Ordospora pajunii but genetically distinct, potentially constituting a new species or genus. These findings provide insight into the ecological and evolutionary tradeoffs involved in host-parasite interactions and introduce a new host-parasite system for this study.
Prendersi Cura: Taking Care of Nature in Perugia, Italy
Date: 2024-03-20
Creator: Katharine Kurtz
Access: Open access
- Cities need more green spaces to adapt to climate change and facilitate community resilience. However, successfully managing green spaces is challenging. City governments consistently employ top-down management practices that limit the benefits, usage, and perception of such spaces as Nature. Further, current management practices overlook socio-cultural factors important to residents. Using the existing categories of urban green spaces (UGS) and informal green spaces (IGS), this article situates the cultural practice prendersi cura as a way to conceptualize successful, bottom-up green space management. The term prendersi cura, meaning “to take care of” in Italian, emerged through interviews in Perugia, Italy, and reflects the socio-ecological value of IGS and the disconnect between residents and city-managed UGS. This study employed mixed methods, combining 10 weeks of participant observation, 13 interviews, and GIS analysis to understand the relationship between Perugians and their green spaces. Results indicate that interviewees did not describe city-supported UGS (i.e. top-down green spaces like parks or historic gardens) as Nature, even if they were areas of dense vegetation and recognized by the City of Perugia in GIS analyses. In contrast, interviewees described IGS (i.e. community gardens, vacant lots, or potted plants) that were unrecognized in city GIS visualizations as Nature, indicating a stronger attachment to green spaces when interviewees had active roles in their management or witnessed community-based management practices. This paper demonstrates the importance of managing green spaces through a socio-ecological framework that considers user perceptions and cultural values. To allow greening initiatives to reach their full potential, it is critical to embrace local values and participation in management practices.
Chains for Change: Mathematical Modeling of Boston’s Eviction Court Cases Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Brian Liu
Access: Access restricted to the Bowdoin Community
Mesurer l’identité : pourquoi les jeunes français se détournent du vin ?Measuring Identity: What’s Turning the Young French Away from Wine?
Date: 2025-01-01
Creator: Siyi (Jonathan) Li
Access: Open access
- We use a randomized discrete‑choice experiment with 381 French adults to investigate why France’s wine consumption decline is most pronounced among the young. The treatment group subjects were primed via a video about France’s viticultural heritage, which raises the probability of choosing French red wine over French amber beer by 14 percentage points for Generation X but lowers it by 15 points for Generation Z. Using observational data collected after the experiment, 2SLS estimates show that the decline of wine in France is primarily due to a weakened sense of “French wine identity.” The study provides the first causal evidence for the role of identity in consumption choices and cautions that heritage‑based marketing may backfire with younger cohorts, suggesting instead modernity‑ and sustainability‑oriented strategies for the wine sector.
Building (Cellular) Barriers: Identifying cellularization dynamics involving somatic Xchromosome eliminations in Bradysia coprophila embryonic development This record is embargoed.
Date: 2025-01-01
Creator: Aale J. Agans
Access: Permanent restriction
Convolutional Squeeze and Excitation Networks
Date: 2025-01-01
Creator: Kavi Sarna
Access: Open access
- Squeeze-and-Excitation (SE) networks improve CNN feature learning by channel-wise attention, but their global pooling strategy discards spatial context. In this work, we reinterpret the SE block’s excitation mechanism as a convolution operation, which leads to a novel patched pooling design. Instead of global average pooling, we propose to divide feature maps into patches and pool within each patch, preserving local spatial information for attention. The excitation step is implemented with 1x1 convolutions (replacing the original SE fully-connected layers), enabling the model to learn adaptive channel reweighting efficiently across those patches. This Convolutional Squeeze-and-Excitation (CSE) approach yields spatially aware feature recalibration with minimal overhead. We evaluate CSE across multiple CNN architectures (including a custom ConvNet and ResNet) on image classification tasks (Fashion-MNIST, CIFAR-10). The results show consistent accuracy improvements over standard SE blocks. Moreover, we demonstrate the generality of patched pooling by integrating it with other attention modules like Efficient Channel Attention (ECA) and Global Context (GC), achieving further gains. Our findings highlight that incorporating localized pooling in SE-style attention significantly enhances representation learning across diverse scenarios.
Gracefully Navigating Industry Exit: Modeling Regional Climate Change-Driven Decline in Maine’s Lobster Fishery and the Urgent Need for Statewide Comprehensive Cost Data Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Luisa Isabelle Louchheim
Access: Access restricted to the Bowdoin Community
Modulation of migratory and breeding phenologies by Maine’s common loons (Gavia immer) in response to climate conditions Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Henry Grant Marriott
Access: Access restricted to the Bowdoin Community
Enchantresses through Time and Space: Examining Feminine Agency and Narrative Resistance
from Camelot to Salem
Date: 2025-01-01
Creator: Isabelle Sungsil Lee
Access: Open access
Rescentment: Reclaiming the Olfactory Sense in Contemporary Asian Diaspora Literature
Date: 2025-01-01
Creator: Maya Juliette Le
Access: Open access
When Populists Come to Power: A US-UK Comparative Analysis Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Ari Edward Bersch
Access: Access restricted to the Bowdoin Community
The Art of Distancing Desire: Queer Female Possibility in British and French Nineteenth-Century Visual Culture Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Julia Smart
Access: Access restricted to the Bowdoin Community
The Politics of Land Rights in the Transition to Democratic South Africa: The Rise and Fall of the Constitutional Property Clause
Date: 2019-05-01
Creator: Anna Louisa Roosevelt Lennon
Access: Open access
Personally Relevant Indoor Nature Imagery’s Impact on Students’ Well-Being, Connection to Nature, and Eco-Conscious Behaviors
Date: 2019-05-01
Creator: Sarena Sabine
Access: Open access
- Previous research has shown that experiences in nature are predictive of increased connection to nature, well-being, and pro-environmental behavior. The current study investigated whether daily exposure to indoor nature imagery would also improve well-being and eco-conscious behaviors, and whether personally relevant images would enhance this hypothesized effect. Participants completed a test assessing baseline connection to nature and well-being, specifically satisfaction with life, positive and negative emotions, and stress. In the 2 (Nature vs. Built) X 2 (Familiar vs. Unfamiliar) study design, 125 participants either received a poster from a photo that they submitted (a personally-relevant nature scene or personally-relevant built scene) or a poster of an unfamiliar natural or built scene. After four weeks of daily exposure to this new poster in their home, participants completed a post-test which included the same measures of well-being and connection to nature, along with a novel eco-conscious behaviors measure involving environmental petitions. The nature intervention significantly improved participants’ satisfaction with life. The personal relevancy of images did not enhance well-being, either alone nor in interaction with image content. The finding that daily exposure could lead to improved well-being has implications for addressing mental health concerns.
Does the neuropeptide GYS modulate stretch feedback pathways in the lobster cardiac neuromuscular system?
Date: 2014-08-01
Creator: Tricia Hartley
Access: Open access
- In many animals, there are groups of neurons, known as central pattern generators (CPGs), which are capable of controlling major everyday life functions. CPGs are responsible for functions that require patterned rhythmic activity, such as the heartbeat, digestion and locomotion. A CPG called the cardiac ganglion, consisting of only nine neurons, controls the rhythmic beating of the heart of the American lobster, Homarus americanus, by stimulating the muscle cells of the heart.My summer consisted of two separate projects in Patsy Dickinson’s neurophysiology lab, both studying the interaction of the cardiac ganglion with neuropeptides. These neuropeptides, GYSDRNYLRFamide (GYS) and SGRNFLRFamide (SGRN) are released hormonally into the cardiac neuromuscular system. The overarching goal of both projects was to determine the role of these neuropeptides in the lobster’s cardiac neuromuscular system.For my first project, I studied the interaction of the neuropeptide GYS with the stretch receptors of the lobster heart. Previous research has found these stretch receptors to be a form of excitatory feedback from the lobster heart to the cardiac ganglion, as heartbeat amplitude and frequency increase as heart is stretched. Further, the dendrites along the cardiac ganglion have been found to be stretch-sensitive, meaning when these dendrites were cut, this excitatory response is no longer observed. By stretching the heart with the dendrites intact and with GYS and next when the dendrites were cut and with GYS, the goal of this project was to determine if GYS would alter the feedback of the stretch receptors back to the cardiac ganglion to change heartbeat frequency and amplitude. Unfortunately, the intricacy involved in being able to cut the dendrites while allowing the heart to continue to beat proved very difficult and I moved on to my next project.The goal of my next project was to examine the interactions of the neuropeptides GYS and SGRN with the decreased and increased presence of nitric oxide, the second form of feedback from the heart muscle to the cardiac ganglion. Previous research shows nitric oxide as having an inhibitory effect, decreasing heartbeat amplitude and frequency. By applying both GYS and SGRN to both the isolated cardiac ganglion and the whole heart in the presence of both a nitric oxide inhibitor and donor, the hope is to be able to determine the interaction of these peptides with and without the presence of the feedback of nitric oxide. Because I started this project later in the summer, with the assistance of Sophie Janes’ data, I have been able to look at the effects of GYS on the whole heart, in addition to the combination of GYS with L-NA, a nitric oxide inhibitor. So far, the data has shown that the combination of GYS with L-NA causes less of a decrease in heartbeat frequency than GYS alone, which shows a significant decrease. We predict this is because GYS enhances the nitric oxide pathway, while L-NA is blocking the nitric oxide pathway, thus giving insight into the role of GYS within the lobster’s cardiac neuromuscular system. For my senior independent study I hope to continue this research and be able to continue to compile data for both SGRN and GYS on the isolated cardiac ganglion as well as on the whole heart, with a nitric oxide inhibitor and donor. Final Report of research funded by a Doherty Coastal Studies Research Fellowship.
A molecular analysis of green crab diets in Casco Bay, Maine
Date: 2015-03-01
Creator: Aidan W. Short, David B. Carlon
Access: Open access
- A new wave of green crabs Carcinus maenus is sweeping through the Gulf of Maine (GOM). While first reports of green crabs in the GOM date from the early 1900s, populations in southern GOM have exploded in the last five years. In the Casco Bay region, this unusually high abundance is associated with poor commercial shellfish landings and the decline of eel grass habitat (Zostera marina). To determine the mechanistic roles green crabs play in direct and indirect ecological interactions, it is important to understand diet breadth, and how feeding preferences change in response to ecological context. Since green crabs are omnivorous, traditional approaches to diet analysis via hard parts suffer from substantial bias. We are using DNA barcoding and next generation sequencing (NGS) to analyze green crab diets from a longitudinal sampling design in Casco Bay. In addition to a temporal dimension, our design includes two habitats: clam flats and eel grass beds. We have now sampled ~ 1000 crabs and have processed 460 individual stomachs from a range of sizes and both sexes. Here we will present: our sampling design, our NGS pipeline, and preliminary analysis from a lobster-specific (Homarus americanus) probe. Presenting author status: Undergraduate Preferred presentation type: Poster Preferred topics: 3. Biological invasions; 18. Molecular ecology Benthic Ecology Meeting, 2015 Quebec City, Canada Aidan Short was an undergraduate student at Bowdoin College when this research was conducted.
"We are your wives, sisters, daughters, mothers and friends:" United States' Women's Stories from the Public to the Archive Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2019-01-01
Creator: Sadie LoGerfo-Olsen
Access: Access restricted to the Bowdoin Community
Urban Modernity and Turbulent Water: Toward a Transnational History of Expansion in Northern Japan, 1866-1882 Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2018-05-01
Creator: Ethan Barkalow
Access: Access restricted to the Bowdoin Community
Long-term trends in tropical fish larvae of the Hawaiian Islands revealed by DNA barcoding
Date: 2014-08-01
Creator: Jack Mitchell
Access: Open access
- DNA Barcoding is the identification of organisms through the use of a standardized portion of the genome, a concept first suggested by Hebert, et al (2003) and since developed to include standard databases and many campaigns internationally to identify and barcode all species in the world. Because DNA barcoding uses molecular data, rather than morphology, to identify organisms, it allows for the identification of organisms that are morphologically similar or have been processed to the point of unrecognizability. Barcoding has the potential to streamline and enhance conservation efforts drastically. Its "quick and easy" identification process allows better fisheries management, market regulation to ensure vendors are selling what they say they're selling (no more horsemeat burgers or dolphin sushi), and greater enforcement of regulations against the killing and selling of endangered animal products (Minhos et al., 2013). In my work this summer, I've been using DNA barcoding to examine the dynamics of a community of larval fish off the coast of Oahu through a seven-year longitudinal barcoding study. Fish larvae are very hard to identify morphologically because they lack obvious identifying characteristics. For this reason, barcoding is essential for accurately understanding the community structure of such fish. In my work, I analyze a set of sequences from the 5-prime region of the mitochondrial gene cytochrome oxidase subunit 1, widely used as a barcode in the animal kingdom, gathered from fish larvae collected off the coast of Oahu by the University of Hawaii Manoa Biology 301L class. The sampling consisted of a series of oblique plankton tows taken at three depths (5m, 25m, and 50m) between January and April every year from 2007 to 2013. During this period, a total of 833 fish larvae were sampled and sequenced. Using the Barcode of Life Data Systems (BOLD Systems) Identification Engine, I was able to identify 78% of all specimens to family-level or better, representing about 25% of the 202 families of shore fishes known to occur in Hawaiian coastal waters. The data stratification consisted of 7 years, each with three depths and 56 family groups, a 21 by 56 data matrix. In order to see the patterns of the matrix, I used Principal Components Analysis, a form of ordination, which distills multidimensional data to a form that is more easily visualized. This ordination revealed that 2009 and 2011 had highly anomalous community structure in which there were large increases in abundance (greater than three (3) Standard Deviations from the mean) of 12 family groups in each year, indicating concerted change in the structure of ichythoplankton in those years, though the families may be represented by a low number of specimens in the sample. Because these families had little to no representation in other years, we are able to rule out the possibility of results being skewed by a couple of families that showed up in our nets by chance that don't reflect the actual community structure. In these years, the highly anomalous families did not overlap, indicating that the factors causing the anomalies were non-identical. In 2009 there were eight families that deviated from the mean by over four (4) Standard Deviations, and in 2011 there were ten. Though the biggest groups of deviant families in both years were reef fish and mesopelagic fish, tropical habitat ranged from shallow water benthic (sea-bed) fish such as Ophichthidae, to bathypelagic (deep sea) fish such as the anglerfish family Ceratiidae. In my last few weeks working on this project I am exploring what environmental factors may have had a hand in such anomalies. El Niño cycles may have had a hand, as there was a weak La Niña (slightly cooler waters) anomaly leading into 2009, and a very strong La Niña (drastically cooler waters) anomaly leading into 2011 ("Cold and Warm Episodes by Season," 2014). The differences in community structure I detected had different signs, that is the co-variance of fish families was different for each of these years. This suggests that water temperature itself may not be causing these ecological patterns. A more likely hypothesis links the effects of El Niño/La Niña on oceanographic circulation throughout the Pacific and even near-shore in the Hawaiian Islands. These changes can drive differences in the delivery of larvae to the islands, as well as advection away from the islands. Further research in the remainder of the summer will attempt to gather more information on what may have caused the community structure anomalies. Final Report of research funded by Mary Lou Zeeman’s NSF grant - Computational Sustainability (NSF-CCF-0832788).
N,N’-Dimethyimidazolium-2-Carboxylate as a Ligand Precursor for the Accession of a Constrained Olefin Dimerization Catalyst
Date: 2020-01-01
Creator: Michael Harris
Access: Open access
- A significant market share of modern plastics is held by long-chain hydrocarbon polymers, such as polyethylene and polypropylene, properties of which can be dramatically changed by addition of linear α-olefins. Production of linear α-olefins involves the creation of many unwanted byproducts, representing significant quantities of both economic and ecological waste. While catalysts have been designed to selectively produce industrially useful olefins, these catalysts often encounter challenges such as synthesis of other unwanted byproducts, slow reaction times, and difficulty of synthesis. Based on one such prior catalyst, we report here synthetic work towards a cobalt catalyst with a constrained N-heterocyclic carbene supporting ligand predicted to allow for more favorable product distributions. Synthesis of two precursors to a sterically unhindered N-heterocyclic carbene, as well as development of a synthetic protocol for the coordination of N,N’- dimethylimidazolium-2-carboxylate to Cp*Co(ethene)2 was completed. Activation of the precatalyst and preliminary catalytic experiments were performed, though abbreviated research periods made complete analysis impossible. Finally, we report evidence of the formation of a novel cobalt-NHC dimer as a temperature controlled byproduct of the desired catalyst synthesis.
“One of Folly’s Failures”: Plessy v. Ferguson (1896) and the Decline of the Thirteenth Amendment This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Grace Ann Fenwick
Access: Embargoed
Mechanisms underlying variable responses to the neuropeptide C-type allatostatin (AST-C) across isoforms and among individuals in the American lobster, Homarus americanus
Date: 2020-01-01
Creator: Audrey J. Muscato
Access: Open access
- Central pattern generators (CPGs) produce patterned outputs independent of sensory input. The cardiac neuromuscular system of the American lobster (Homarus americanus) is driven by a CPG called the cardiac ganglion (CG), which is composed of nine neurons, making it a model system of study. Modulation of CPGs allows for functional flexibility. One neuropeptide family that modulates the CG is C-type allatostatin (AST-C I-III). Previous research has shown variation in the responses of the CG across the three isoforms and among individuals. First, we investigated why AST-C I and III elicit responses that are more similar to each other than they are to the responses elicited by AST-C II. We hypothesized that an amino acid difference in the conserved sequence was responsible for the observed variation in responses. We synthesized isoforms of AST-C that replaced the endogenous amino acid and recorded responses to these isoforms. The identity of one particular amino acid in the conserved sequence seems to be responsible for variations in responses in frequency. Next, we focused on variation among individuals in their responses to AST-C I and III. We hypothesized that the mechanism behind this individual variation is differential expression of AST-C receptors and/or their downstream targets. We recorded physiological responses of the cardiac system to AST-C and then sequenced CG RNA from the same lobsters. Differential expression of one of the AST-C receptors and a number of downstream factors is correlated with physiological response. These findings inspire further experimentation investigating molt cycle as the underlying cause.
Alongside Despair: Signs of Life on the River des Peres
Date: 2020-01-01
Creator: Marina Henke
Access: Open access
- This River des Peres is a partially enclosed river which runs through St. Louis, Missouri. Used since prior to the city’s founding, the des Peres has gone through two considerable engineering projects: one in 1901 in light of the World’s Fair, and one in 1923, which encapsulated more than half of the river and placed nearly five miles of it underground. Presently, the des Peres constitutes the backbone of the sanitary and sewer system of St. Louis city and county. Ultimately, the river offers a broad meditation on what it means to live around and in a “natural” waterway that is simultaneously not natural at all. Themes of St. Louis are equally reflected in the river: of environmental racism, of Midwestern decline, and of urban decay and renewal. Additionally, those who interact with the river prove a broad cast of characters. Through using a selection of interviews with locals, alongside an engagement with the work of contemporary poet Donald Finkel, this piece of creative nonfiction explores the multiplicity, and ultimately the value, of distorted natural spaces.
Non-genomic effects of steroids on teleost fish olfaction: behavioral and anatomical approaches Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Leah B Kratochvil
Access: Access restricted to the Bowdoin Community
Wnt Signaling is Dispensable to Formation of the First Tooth in D. Rerio This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Zachary C. LeBlanc
Access: Embargoed
Tapping at the Windows: A Collection This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Samuel Milligan
Access: Embargoed
Performing Sor Juana: Reimagining a Mexican Literary Figure in the 21st Century
Date: 2020-01-01
Creator: Uriel López-Serrano
Access: Open access
- Sor Juana Inés de la Cruz (c. 1648-1695) was a Mexican nun, poet, playwright, and scholar from the colonial era. She has become an icon for various global, social, and political movements. This project looks at four dramatic works created by Sorjuanistas who reimagine Sor Juana’s story for contemporary audiences living in the United States. The works included in this essay are Estela Portillo-Trambley’s Sor Juana (1986), Karen Zacarías’s The Sins of Sor Juana (2001), and Alicia Gaspar de Alba’s “Interview with Sor Juana Inés de la Cruz” (1998/2014) and her newest work, Juana: An Opera in Two Acts (2019), libretto by Carla Lucero. In addition to reimagining Sor Juana’s story, these dramatic works expose the sexism, racism, and xenophobia perpetuated by U.S institutions of power that discriminate against Latin@ and Chican@ individuals. By shedding light on the social injustices that existed during the colonial era, an embodied Sor Juana teaches audiences how to resist and mobilize against such oppressive powers. Sor Juana’s narrative on stage is necessary because she is a role model for Latin@s/Chican@s. Sorjuanistas remind us that the body can be used to retell the narratives of the silenced individuals who are victims of oppression. By developing heritage performances, Sorjuanistas challenge histories that silence and overlook social injustices. Witnessing Sor Juana on stage triggers emotional responses to the past which allow historical actors to obtain intellectual, emotional, and political agency in an effort to affirm and remember particular contemporary and future commitments to fighting social injustices.
An Analysis of Hezbollah’s Media Platforms, Focusing on Themes, Narratives and Strategy Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2020-01-01
Creator: Nichole Irving
Access: Access restricted to the Bowdoin Community
Noninvasive Memory Modulation Via Targeted Theta TACS Entrainment of the Frontoparietal Network Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2026-06-01
Date: 2021-01-01
Creator: Brandon S Lee
Access: Access restricted to the Bowdoin Community
Down in arms: Marine climate stress inhibits growth and calcification of regenerating Asterias forbesi (Echinodermata: Asteroidea) arms
Date: 2021-01-01
Creator: Hannah L. Randazzo
Access: Open access
- Anthropogenic CO2 is changing the pCO2, temperature, and carbonate chemistry of seawater. These processes are termed ocean acidification (OA) and ocean warming. Previous studies suggest two opposing hypotheses for the way in which marine climate stress will influence echinoderm calcification, metabolic efficiency, and reproduction: either an additive or synergistic effect. Sea stars have a regenerative capacity, which may be particularly affected while rebuilding calcium carbonate arm structures, leading to changes in arm growth and calcification. In this study, Asterias forbesi were exposed to ocean water of either ambient, high temperature, high pCO2, or high temperature and high pCO2 for 60 days, and the regeneration length of the amputated arm was measured weekly. Ocean acidification conditions (pCO2 ~1180 μatm) had a negative impact on regenerated arm length, and an increase in temperature of +4°C above ambient conditions (Fall, Southern Gulf of Maine) had a positive effect on regenerated arm length, but the additive effects of these two factors resulted in smaller regenerated arms compared to ambient conditions. Sea stars regenerating under high pCO2 exhibited a lower proportion of calcified mass, which could be the result of a more energetically demanding calcification process associated with marine climate stress. These results indicate that A. forbesi calcification is sensitive to increasing pCO2, and that climate change will have an overall net negative effect on sea star arm regeneration. Such effects could translate into lower predation rates by a key consumer in the temperate rocky intertidal of North America.
Identification and characterization of genes involved in Helicobacter pylori lipopolysaccharide and glycoprotein biosynthesis Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Andrew James Mulholland
Access: Access restricted to the Bowdoin Community
Determining the sites at which neuromodulators exert peripheral effects in the cardiac neuromuscular system of the American Lobster, Homarus americanus
Date: 2021-01-01
Creator: Audrey Elizabeth Jordan
Access: Open access
- Networks of neurons known as central pattern generators (CPGs) generate rhythmic patterns of output to drive behaviors like locomotion. CPGs are relatively fixed networks that produce consistent patterns in the absence of other inputs. The heart contractions of the Homarus americanus are neurogenic and controlled by the CPG known as the cardiac ganglion. Neuromodulators can enable flexibility in CPG motor output, and also on muscle contractions by acting on the neuromuscular junction and the muscle itself. A tissue-specific transcriptome gleaned from the cardiac ganglion and cardiac muscle of the American lobster was used to predict the sites and sources of a variety of crustacean neuromodulators. If corresponding receptors were predicted to be expressed in the cardiac muscle, then it was hypothesized that the neuropeptide had peripheral effects. One peptide for which a cardiac muscle receptor was identified is myosuppressin. Myosuppressin has been shown to have modulatory effects at the cardiac neuromuscular system of the American lobster. In previous research, myosuppressin had modulatory effects on the periphery of cardiac neuromuscular system alone. It remains an open question of whether myosuppressin acts on the cardiac muscle directly, if it is exerting its effects at the neuromuscular junction (NMJ), or both. To test this, I performed physiological experiments on the isolated NMJ. Myosuppressin did not modulate the amplitude of the excitatory junction potentials. Since no modulatory effects were seen at the NMJ, the cardiac muscle was isolated from the cardiac ganglion and then glutamate-evoked contractions were stimulated. I showed that myosuppressin increased glutamate-evoked contraction amplitude. These data suggest myosuppressin exerts its peripheral effects at the cardiac muscle and not the NMJ.
Los trucos debajo de la mesa: Juegos y simulacros en la cultura y literatura argentina Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2020-01-01
Creator: Eliana Miller
Access: Access restricted to the Bowdoin Community
Investigating the Effect of Side Chains with Hydrogen Bonding Capabilities on Peptoid Catalysts for Enantioselective Trifluoromethylation of 4-Chlorobenzaldehyde Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2020-01-01
Creator: Rebecca Londoner
Access: Access restricted to the Bowdoin Community
Characterization of O-Linked Glycosylated Neuropeptides in the American Lobster (Homarus americanus): The Use of Peptide Labeling Following Beta Elimination
Date: 2020-01-01
Creator: Edward Myron Bull
Access: Open access
- Neuropeptides are a class of small peptides that govern various neurological functions, and the American lobster (Homarus americanus) provides a model system for their characterization. Neuropeptides are commonly post-translationally modified (PTM), and one common PTM is glycosylation. Past research in the Stemmler lab has found glycosylated neuropeptides in H. americanus; however, the extent and biological role of this modification has not been well characterized. This study was undertaken to determine the number of glycosylated peptides in the sinus glands of H. americanus and to develop an approach to tag the site of glycosylation using beta-elimination chemistry. LC-MS paired with high pH reverse phase fractionation was used to survey for glycosylated neuropeptides and beta elimination with an amine tag was used as an approach to characterize the site of glycosylation. Our results indicate that high pH fractionation is a useful approach to simplify complex mixtures of neuropeptides and improve glycopeptide detection. Efforts to use beta elimination and tagging to characterize glycosylated neuropeptides have been less successful. Beta elimination of full length peptides resulted in peptide degradation. An approach utilizing chymotrypsin to reduce peptide size coupled with beta elimination and labeling with 2-dimethylaminoethanethiol showed less evidence for degradation, and this approach yielded data isolating two potential serine residues for the site of glycosylation; however, the data was not sufficient to distinguish the two sites. Work to optimize reaction conditions using a glycopeptide standard showed that multiple isomeric products were formed during beta elimination. With the goal of optimizing reaction conditions, future work will further examine reaction kinetics to eventually apply the approach to the entire sinus gland
Classifying Flow-kick Equilibria: Reactivity and Transient Behavior in the Variational Equation
Date: 2020-01-01
Creator: Alanna Haslam
Access: Open access
- In light of concerns about climate change, there is interest in how sustainable management can maintain the resilience of ecosystems. We use flow-kick dynamical systems to model ecosystems subject to a constant kick occurring every τ time units. We classify the stability of flow-kick equilibria to determine which management strategies result in desirable long-term characteristics. To classify the stability of a flow-kick equilibrium, we classify the linearization of the time-τ map given by the time-τ map of the variational equation about the equilibrium trajectory. Since the variational equation is a non-autonomous linear differential equation, we conjecture that the asymptotic stability classification of each instantaneous local linearization along the equilibrium trajectory indicates the stability of the variational time-τ map. In Chapter 3, we prove this conjecture holds when all of the asymptotic and transient behavior of the instantaneous local linearizations is the same. To explore whether the conjecture holds in general, we ask: To what degree can transient behavior differ from asymptotic behavior? Under what conditions can this transient behavior accumulate asymptotically? In Chapter 4, we develop the radial and tangential velocity framework to characterize transient behavior in autonomous linear systems. In Chapter 5, we use this framework to construct an example of a non-autonomous linear system whose time-τ map has asymptotic behavior that differs from the asymptotic behavior of each instantaneous linear system that composes it. Future work seeks to determine whether this constructed example can arise as a variational equation, and thus provide a counterexample for our conjecture.
Reading & Teaching Chaucer: the "Good Wif"?
Date: 2020-01-01
Creator: Sophie Friedman
Access: Open access
- This two-chapter project applies formalist and feminist thinking to the thirty-line description of the Wife of Bath in Geoffrey Chaucer’s medieval, British work The Canterbury Tales. It is an interdisciplinary project; it studies how to read and teach Chaucer at the secondary level based off of these two approaches. In this formalist chapter, I study narrative voice, rhyme, irony, and ekphrasis, writing about the history and function of each of those tools and their role in the passage. I argue that the formalist close reading approach is an excellent teaching tool that generates thorough, rigorous, and joyful reading. In this feminist chapter, I compile a critical literary history of scholarly feminist and pre-feminist engagement with the passage over time. I read into an underlying genotype text, arguing that the Wife of Bath was a female entrepreneur who used textiles as a means of social, professional, and aesthetic expression and empowerment. Then I advocate for a feminist ethical teaching approach—one where we use the text as a non-ethical space in which to explore ethical questions surrounding gender. Ultimately, I argue that feminist and formalist approaches are interdependent and complementary; for both reading and teaching Chaucer, they stand stronger together.