Showing 101 - 150 of 681 Items
Characterizing the influence of Atlantic water intrusion on water mass formation and primary production in Kongsfjorden, Svalbard
Date: 2015-05-01
Creator: Courtney Michelle Payne
Access: Open access
- With warming global temperatures and changes to large-scale ocean circulation patterns, warm water intrusion into Arctic fjords is increasingly affecting fragile polar ecosystems. This study investigated how warm Atlantic water intrusion and the tidewater glacial melting it causes impacted water mass formation and primary productivity in Kongsfjorden, Svalbard. Data were collected over a 2-week period during the height of the melt season in August near the Kronebreen/Kongsvegen glacier complex, the most rapidly retreating glacier in Spitsbergen. Since 1998, intruding waters have warmed between 4 and 5.5˚C, which has prevented sea ice formation and changed the characteristics of fjord bottom waters. Increased glacial melting in the last decade has changed the characteristics of surface waters in the fjord. Modeled light fields suggest that suspended sediment in this glacial meltwater has reduced the euphotic zone close to the ice face, preventing high primary production in both the consistent and intermittent sediment-laden meltwater plumes. However, measurements collected close to terrestrially terminating glaciers indicate that extremely high primary production can occur in conditions of low turbidity. The results of this study support a three-part model of the effects of warm-water intrusion on water mass formation and primary production, where changes in sea ice coverage and tidewater glacial dynamics affect the optical light field. This model allows for spatial predictions for the most likely impacts of warm water intrusion on primary production in Spitsbergen, and could be extrapolated out to explore potential phytoplankton response in other regions susceptible to warm-water intrusion.
Making Human Beings and Citizens: The Educational Philosophies of Jean-Jacques Rousseau and Mary Wollstonecraft Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Mollie Claire Eisner
Access: Access restricted to the Bowdoin Community
The Jewish “Other” in Argentina: Antisemitism, Exclusion, and the Formation of Argentine Nationalism and Identity in the 20th Century and during Military Rule (1976-1983)
Date: 2021-01-01
Creator: Marcus Helble
Access: Open access
- Throughout the 20th century, Argentine leaders and social actors attempted to shape distinct national identities and a sense of nationalism that corresponded to their respective political ideologies. Beginning in the first couple decades of the 20th century, the formation of a Jewish “other” would be central to the construction of both Argentine national identity and nationalism. This thesis argues that the military dictatorship that led the country from 1976 to 1983 built on this othering of the Jewish community as military leaders sought to forge a national identity linked to Catholicism. It focuses first on three separate periods of the early and mid-20th centuries and how governments in that period built, maintained, and altered the view of the Jewish community as a not fully Argentine “other” living in the country. Using several editions of a far-right antisemitic periodical, declassified State Department documents, and testimonies of Jewish political prisoners and soldiers, the thesis transitions to focus on the military dictatorship of the 1970s and 1980s. It examines two separate periods of the dictatorship, highlighting first the role antisemitic beliefs, and opposing such views, had in an internal power struggle within the military government. In the second period of the dictatorship, during the Malvinas (Falklands) War, the thesis examines how antisemitism became a central part of the military’s efforts to consolidate a sense of national unity during the conflict, even as Jews participated largely for the first time within Argentine nationalism and the military.
All That Influences the Condition of Women: The Moral Foundations of Female Education in Tocqueville and Rousseau This record is embargoed.
- Embargo End Date: 2026-05-20
Date: 2021-01-01
Creator: Nicole Danielle Tjin A Djie
Access: Embargoed
Caring like a state: The elaboration of a care ideology in Peru and Sri Lanka in the 20th century
Date: 2015-05-01
Creator: Katharine Herman
Access: Open access
- This project compares the interaction between the government and the population in both Peru and Sri Lanka through the 20th century, focusing on the provision of care (services, benefits, and recognition as provided by the governing apparatus) as a locus for their most meaningful interaction. The provision of care can be seen as a form of communication established in certain practices, symbols, and discourses. Moreover, the provision of care works to reorient the subject population into a more beneficial relationship with the state–notably one of increased dependence and trust. Through the elaboration of what care is and how it functions, a care ideology is established creating a terrain through which the politics of the governed and the governing alike can be legitimized. Care ideology can then be considered a further articulation of the state idea, creating a dialogue about how governance can or should be affected within a certain context. These case studies then illustrate the terrain over which both of these governing bodies work. In Sri Lanka, the governing apparatus provides a means for citizens to live a symbolically meaningful life through paddy farming. In Peru, the governing apparatus provides access to the state through civil infrastructure like roads and education. Through care, material goods become invested with meaning and the state idea becomes materialized. Care is a then substantial project undertaken by the state to ensure its own reproduction and further widen the possibilities for the state project to be effected through its own citizens.
Accretion Onto a Black Hole at the Center of a Neutron Star: Nuclear Equations of State
Date: 2022-01-01
Creator: Sophia Christina Schnauck
Access: Open access
- A recent re-examination of Bondi accretion (see Richards, Baumgarte and Shapiro (2021)) revealed that, for stiff equations of state (EOSs), steady-state accretion can only occur for accretion rates exceeding a certain minimum. To date, this result has been explored only for gamma-law equations of state. Instead, we consider accretion onto a small black hole residing at the center of a neutron star governed by a more realistic nuclear EOS. We generalize the relativistic Bondi solution for such EOSs, approximated by piecewise polytropes, and thereby obtain analytical expressions for the accretion rates which were reflected in our numerical simulations. After taking several different piecewise EOSs at different neutron star densities into account, the accretion rates of the different EOSs were only slightly larger than the previously observed minimum. In other words there appears to be evidence for a nearly universal accretion rate that depends only on the black hole mass. However, we also observed that for certain densities the fluid profiles of several EOSs exhibited superluminal sound speeds outside the horizon of the black hole, suggesting that the EOSs are not appropriate at these densities.
Evaluating Dam Relicensing and River Herring Habitat Restoration from a Broad, Multi-Ecosystem Perspective
Date: 2022-01-01
Creator: Matthew L. Thomas
Access: Open access
- This study investigates the potential benefits of using a broad, multi-ecosystem analysis in the licensing and relicensing of hydropower facilities. Specifically, it considers the impact of river herring restoration on coastal food webs and cod and other groundfish populations in the Gulf of Maine. The past two decades of research on fisheries management, ecosystem connectivity, and the connection between river herring and groundfish in the Gulf of Maine have resulted in a better understanding of the ways in which human activities, such as dam building, influence ecological processes. The paper analyzes two case studies of six Maine dams currently engaged in the Federal Energy Regulatory Commission’s (FERC) hydroelectric dam relicensing process. The analysis illustrates the shortcomings of the Federal Power Act’s provisions that address the balancing of ecological and power generation concerns. Following the case studies, a series of policy recommendations are presented to encourage a more transparent and predictable relicensing process that adequately values both ecological and power generation goals. Changes are suggested for both the FERC process itself and the process by which state and federal resource agencies may provide comments regarding how a proposed dam licensing or relicensing affects natural resources under their jurisdiction. The proposed policy recommendations will increase the resilience of natural systems as they adapt to climate impacts.
An Investigation on Data Gaps in Scope 3 Emissions Accounting and Disclosure using 2010-2021 Carbon Disclosure Project (CDP) Questionnaire Responses This record is embargoed.
- Embargo End Date: 2027-05-17
Date: 2022-01-01
Creator: Samara Nassor
Access: Embargoed
Antimicrobial Compounds in the Lobster, Homarus americanus: An Investigation of Lobster Shell Extracts This record is embargoed.
- Embargo End Date: 2027-05-19
Date: 2022-01-01
Creator: Usira Ahmed Ali
Access: Embargoed
“Unstuck in Time and Space”: Time Travels in Teen Cinema Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Hallowell Lyne
Access: Access restricted to the Bowdoin Community
Chromatin-conformation differences in natural populations of D. melanogaster 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: Nicholas J. Purchase
Access: Access restricted to the Bowdoin Community
The Photocatalytic Degradation of Ibuprofen and Atenolol Using Bismuth Oxychloride and Titanium Dioxide
Date: 2021-01-01
Creator: Kamyron Anthony Speller
Access: Open access
- Pharmaceuticals and personal care products (PPCPs) are contaminating natural bodies of water and are problematic for aquatic organisms and ecosystems. Generally, PPCPs are introduced to water systems due to incomplete removal by wastewater treatment plants (WWTPs). As such, it is vital to find ways to remediate these problematic contaminants before they are discharged into the environment. In this study, two photocatalysts¾titanium dioxide (TiO2) and bismuth oxychloride (BiOCl)¾were compared to determine their relative efficiencies (degradation rates) and dominant degradation mechanism (hydroxyl radical production or direct oxidation) with the goal of photocatalytically degrading two pharmaceuticals, atenolol and ibuprofen, using UV (254 nm) light. While TiO2 has been used extensively for photocatalytic degradation, BiOCl is a newer photocatalyst. The two pharmaceuticals selected for study represent two large classes of drugs (aryloxypropanolamine and propionic acid derivatives, respectively) that have been detected in the influent into and effluent from wastewater treatment plants and in the environment. When irradiated at 254 nm, BiOCl degrades ibuprofen with a rate constant 15 times greater than TiO2. On the other hand, TiO2 degrades atenolol with a rate constant 2.2 times greater than BiOCl. LCMS analysis of photodegradation products reveals different products produced by the two photocatalysts, providing evidence for the dominance of different degradation mechanisms for the two photocatalysts. In summary, this work suggests that BiOCl, potentially used in combination with TiO2, holds potential for degrading PPCPs in natural bodies of water.
Palimpsestuous London: Spatial and Temporal Layering in Fin-de-Siècle Victorian Fiction Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2015-05-01
Creator: Elisabeth A Strayer
Access: Access restricted to the Bowdoin Community
Semaphorin-Induced Plasticity in the Nervous System of the Cricket, Gryllus bimaculatus
Date: 2021-01-01
Creator: Alicia G. Edwards
Access: Open access
- The adult auditory system of the cricket, Gryllus bimaculatus, exhibits a rare example of neuronal plasticity. Upon deafferentation, we observe medial dendrites that normally respect the midline of the PTG in the central nervous system sprouting across the boundary and forming synaptic connections with the contralateral auditory afferents. The Horch Lab has investigated key molecular factors that might play a causal role in this paradigm. Specifically, the protein Sema1a.2 comes from a guidance molecule family and has a role in developmental neuronal plasticity in other organisms. In this study, I explored the role of Sema1a.2 in the neuronal plasticity of the adult auditory system of the cricket by conducting a series of dsRNA knockdown experiments targeting Sema1a.2 followed by backfill procedures in which we iontophoresed dye into the Ascending Neurons (ANs) to visualize the anatomical effects of the knockdown experiments using confocal microscopy. We found that there were no significant differences between animals injected with dsRNA against GFP and Sema1a.2 volume, with respect to qualitative and quantitative data. However, we believe with an increase in cohort size, the trends observed, particularly the effect of Sema1a.2 knockdowns on CWM and CBM volumes, will become more pronounced and significant. Potential future pathways could include conducting double knockdowns of Sema1a.2 and Sema2a to observe if these two proteins are working together to create a more obvious effect on midline crossing and branching. Other options also include looking into other protein families that might be the causing factor in this rare phenomenon (toll-like receptors).
Characterization of Yellow Family Proteins in Gryllus bimaculatus
Date: 2021-01-01
Creator: Alexandra W. Rubenstein
Access: Open access
- Neuronal plasticity occurs in developing nervous systems, with adult organisms rarely able to recover from neurological damage. The cricket, Gryllus bimaculatus, is useful to study neuronal plasticity due to its reorganization of the auditory system in response to injury beyond development. When a cricket ear is removed and auditory afferents severed, a rare phenomenon occurs: the dendrites of interneurons on the deafferented side cross the typically-respected midline of the prothoracic ganglion to form functional synapses with auditory afferents from the opposite side. To find proteins involved in this phenomenon, the Horch Lab assembled a de novo transcriptome from neurons in the prothoracic ganglion of G. bimaculatus. Differential gene expression analysis revealed upregulated protein yellows post-deafferentation, indicating these proteins could influence neuronal plasticity in the adult cricket CNS. I focused on characterizing the protein yellow family in the cricket. By relating protein yellows evolutionarily, mapping them onto the genome, and analyzing their sequences, I discovered the cricket has 10 yellow genes, including a newly identified yellow-r* and a block of yellows showing synteny with insect genomes. Additionally, yellow-e and -x in crickets are closely related to bacterial yellow, perhaps indicating a role for horizontal gene transfer in yellow gene evolution. The protein upregulated in the cricket CNS is closely related with yellow-f’s in other insects, indicating yellow-f is likely a secreted protein, highly expressed in the CNS, multifunctional, and conserved across insects. Characterizing yellow-f can give insight into how these upregulated proteins might be related to neuronal plasticity in G. bimaculatus.
Jigs, Reels, and “Realness”: An Investigation of Ideas of Authenticity and Tradition in New England French Canadian Music
Date: 2021-01-01
Creator: Lowell Ruck
Access: Open access
- Franco-American culture is increasingly recognized as an integral part of the heritage of Maine and New England, and has attracted growing academic attention in recent years. But while many scholars and cultural promoters focus on the French language in their work on this subject, few studies have considered the position of traditional music in Franco-American communities in the 21st century. This thesis examines French Canadian traditional music as it is played in New England and the ways in which musicians think about authenticity and tradition in their art. Using material from ethnographic interviews, it illuminates how musicians draw from individual, familial, and communal experiences and from past, present, and future conceptions of authentic tradition in their roles as cultural mediators. Ultimately, it suggests that players of French Canadian traditional music interact with this tradition in diverse ways, and that in doing so, they help to maintain the vibrancy of Franco-American cultural practices. La culture franco-américaine est reconnue de plus en plus comme partie intégrante de l’héritage du Maine et de la Nouvelle-Angleterre et attire maintenant l’attention académique. Mais même si beaucoup d’érudits et de promoteurs culturels ciblent la langue française dans leur travail sur ce sujet, peu d’études ont considéré la position de la musique traditionnelle dans les communautés franco-américaines du XXIe siècle. Cette thèse se concentre sur la musique traditionnelle canadienne-française de la Nouvelle-Angleterre et sur les façons dont les musiciens conceptualisent l’authenticité et la tradition dans leur art. En utilisant des entrevues ethnographiques, elle illumine comment les musiciens tirent des expériences individuelles, familiales et communautaires et des idées du passé, du présent et de l’avenir dans leurs rôles comme médiateurs culturels. Finalement, elle suggère que les joueurs de la musique traditionnelle canadienne-française interagissent avec cette tradition de plusieurs façons, et ce faisant, aident à maintenir la brillance des pratiques culturelles franco-américaines.
Possessing Her: Embodying Identity in Exorcism Cinema Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Alicia Echavarria
Access: Access restricted to the Bowdoin Community
Critical Phenomena in the Gravitational Collapse of Electromagnetic Dipole and Quadrupole Waves
Date: 2021-01-01
Creator: Maria F. Perez Mendoza
Access: Open access
- We report on critical phenomena in the gravitational collapse of electromagnetic waves. Generalizing earlier results that focused on dipole electromagnetic waves, we here compare with quadrupole waves in axisymmetry. We perform numerical simulations of dipole and quadrupole wave initial data, fine-tuning both sets of data to the onset of black hole formation in order to study the critical solution and related critical phenomena. We observe that different multipole moments have different symmetries, indicating that the critical solution for electromagnetic waves cannot be unique, at least not globally. This is confirmed in our numerical simulations: while dipole data lead to a single center of collapse, at the center of symmetry, quadrupole data feature two separate centers of collapse on the symmetry axis, above and below the center of symmetry -- reminiscent of similar findings reported for critical collapse of vacuum gravitational waves. While the critical solution for neither the dipole nor the quadrupole data is exactly self-similar, we find that their approximate echoing periods appear to differ, as do the critical exponents. We discuss whether the centers of collapse found for dipole and quadrupole data might all have the same properties, which would suggest a ``local uniqueness" of the critical solution. Instead, we provide some evidence -- including the differing echoing periods and critical exponents -- suggesting that the critical solutions are distinct even locally. We speculate on the implications of our findings for critical phenomena in the collapse of vacuum gravitational waves, which share with electromagnetic waves the absence of a spherically symmetric critical solution.
Hypersensitization of Helicobacter pylori to Antibiotics Through Perturbation of Bacterial Glycan Armor Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2022-01-01
Creator: William J. Rackear
Access: Access restricted to the Bowdoin Community
Illumination, Inspiration, and Inquisition: The 15th and 16th century reception and reaction of Dante’s Divina Commedia in Spain This record is embargoed.
- Embargo End Date: 2025-05-19
Date: 2022-01-01
Creator: Francesca Mauro
Access: Embargoed
Sex- and age-specific susceptibility of parvalbumin neurons to DNA methylation in a model of early life adversity This record is embargoed.
- Embargo End Date: 2025-05-19
Date: 2022-01-01
Creator: Alissa Chen
Access: Embargoed
Religious Negotiation and Identity Formation: Reading Material Religion in Oaxaca’s “Guelaguetza Oficial”
Date: 2023-01-01
Creator: Rene Sebastian Cisneros
Access: Open access
- The Oaxacan Guelaguetza Oficial is a folk-dance festival in the state of Oaxaca, Mexico which takes place on the last two Mondays of July each year. This state-sponsored celebration of Oaxacan identity is intertwined within histories of Indigenous religious belief and Catholic everyday practice. The Guelaguetza Oficial can be traced back to late 19thcentury celebrations venerating the Virgen del Carmen Alto. Oaxaqueños today predominantly practice an Indigenous-Catholic tradition whose rituals, festive scripts, pantheon of popular saints, and immanent understandings of heavenly power over earthly events can be traced back to negotiations between Indigenous forms of popular belief and institutionalized Catholic practice. Through historical and present-day religious tensions between existing modes of Indigenous religious belief and institutionalized Oaxacan Catholic practice, this thesis asserts that while Indigeneity often represented an obstacle to different structures of power in Mexican history, hegemonic institutions eventually came to accept the lasting presence of Indigenous identity and religious life to varying degrees within Mexican society and culture. This resulting reading of Guelaguetza demonstrates how religion is fundamentally implicated in the history of public festival and popular culture in Oaxaca. Furthermore, this thesis argues that Indigenous-Catholicism has not lost its prominence in public space in Oaxaca despite the reforms of post-1910 Oaxacan state and Mexican national politics and the effects of globalized neoliberal economies in the late 20th and early 21st centuries.
Timing the Paleozoic Oxygenation of the Deep Ocean Using Thallium Isotopes This record is embargoed.
- Embargo End Date: 2028-05-17
Date: 2023-01-01
Creator: Jean Nikolas R. Clemente
Access: Embargoed
Sensitivity Analysis of Basins of Attraction for Nelder-Mead
Date: 2022-01-01
Creator: Sonia K. Shah
Access: Open access
- The Nelder-Mead optimization method is a numerical method used to find the minimum of an objective function in a multidimensional space. In this paper, we use this method to study functions - specifically functions with three-dimensional graphs - and create images of the basin of attraction of the function. Three different methods are used to create these images named the systematic point method, randomized centroid method, and systemized centroid method. This paper applies these methods to different functions. The first function has two minima with an equivalent function value. The second function has one global minimum and one local minimum. The last function studied has several minima of different function values. The systematic point method is a reliable method in particular scenarios but is extremely sensitive to changes in the initial simplex. The randomized centroid method was not found to be useful as the basin of attraction images are difficult to understand. This made it particularly troublesome to know when the method was working effectively and when it was not. The systemized centroid method appears to be the most precise and effective method at creating the basin of attraction in most cases. This method rarely fails to find a minimum and is particularly adept at finding global minima more effectively compared to local minima. It is important to remember that these conclusions are simply based off the results of the methods and functions studied and that more effective methods may exist.
"In Loving Virtue": Staging the Virgin Body in Early Modern Drama
Date: 2022-01-01
Creator: Miranda Viederman
Access: Open access
- The aim of this Honors project is to investigate representations of female virginity in Renaissance English dramatic works. I view the period as one in which the womb became the site of a unique renewal of cultural anxieties surrounding the stability of the patriarchy and the inaccessibility of female sexual desire. I am most interested in virginity as a “bodily narrative” dependent on the construction and maintenance of performance. I analyze representations of virginity in female characters from four works of drama originating in the Jacobean period of the English Renaissance, during and after the end of the reign of Elizabeth I, the Virgin Queen. Across four chapters, I examine the characters of Isabella from Shakespeare’s Measure for Measure (1604), Beatrice-Joanna from Thomas Middleton’s The Changeling (1622), the Jailer’s Daughter from Shakespeare and Fletcher’s The Two Noble Kinsmen (1634), and Helen from Shakespeare’s All’s Well That Ends Well (c. 1602-1605). To establish a framework for my readings, I situate each work in its contemporary cultural context, drawing upon Catholic and Protestant religious doctrines, period medical texts, and popular culture. I intend to explore the complex, often contradictory nature of the forms of virginity the plays depict. Still, I hope by uncovering the opportunities these four characters are provided by their virginity, that I can widen the confines of the category.
#IVFgotyou: Instagram IVF Influencers as Social (Media) Support Systems
Date: 2023-01-01
Creator: Susu Gharib
Access: Open access
- This paper details the ways in which IVF and infertility influencers on Instagram use their platforms to resist the silence surrounding reproductive difficulties. The analysis draws upon a thematic analysis of posts tagged with IVF-related hashtags and a semi-structured ethnographic interview with one influencer. Through these methods, I found that influencers build intimate publics through their platforms by sharing their journeys, interacting with followers, and reciprocal support. Within the context of the intimate publics, influencers are able to connect with others who understand their experiences, allowing them to break through the silence they may feel in their offline social groups.
Differential modulation of the Homarus americanus cardiac neuromuscular system across cell types and among neuropeptide isoforms Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Emily R Oleisky
Access: Access restricted to the Bowdoin Community
Protein Transition: Alternative Proteins and Policy Pathways to a More Sustainable Diet in the United States This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Anna Barnes
Access: Embargoed
Analysis of adhesion mutants in Arabidopsis thaliana This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Bridgid Elizabeth Greed
Access: Embargoed
Computational Investigation of the Ground States and Luminescent Excited States of Ruthenium(II) and Platinum(II) Photoactive Complexes: Insights into the Design of New Ruthenium(II)-Based Molecular Photocatalysts and Enhanced Understanding of Metal-Metal Bonded Exciplexes Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Thomas Regan
Access: Access restricted to the Bowdoin Community
The Soviet and American Wars in Afghanistan: Applying Clausewitzian Concepts to Modern Military Failure
Date: 2020-01-01
Creator: Artur Kalandarov
Access: Open access
- This paper evaluates the validity of three concepts from Carl von Clausewitz’s On War as they relate to contemporary military conflict. Utilizing the Soviet and American Wars in Afghanistan as case studies, the paper also offers a model for comparative conflict analysis by expanding upon Clausewitz’s culminating point concept. It argues that – despite limitations to Clausewitz’s theory of war – his concepts of culminating points in military operations, mass and concentration, and changing war aims provide useful insights into counterinsurgency military failures. Chapter One identifies the Soviet and American culminating points. Concluding that the concept of a culminating point is not applicable to the means and objectives of insurgents, it expands upon Clausewitzian theory by presenting an effectual substitute: the Counterinsurgent Acceptance Point. This is the author’s idea, and it is defined as the moment at which the counterinsurgents first publicly call for negotiations with the enemy. As the first public acknowledgment that the insurgents have denied the counterinsurgents a strictly military resolution to the conflict, it marks a crucial shift in the political framework of the war and is a fitting antithesis to the culminating point. Chapters Two and Three show how an inadequate troop presence and unclear war aims harmed Soviet and American efforts in Afghanistan. The development of insurgencies in both wars are studied to pinpoint when both country’s leaderships failed to adopt a Clausewitzian view of war, despite calls to do so by General Colin Powell in 2001 and Marshal Nikolai Ogarkov in 1979.
The role of behavioral diversity in determining the extent to which the cardiac ganglion is modulated in three species of crab
Date: 2020-01-01
Creator: Grace Bukowski-Thall
Access: Open access
- Central pattern generators (CPGs) are neural networks that generate the rhythmic outputs that control behaviors such as locomotion, respiration, and chewing. The stomatogastric nervous system (STNS), which contains the CPGs that control foregut movement, and the cardiac ganglion (CG), which is a CPG that controls heartbeat, are two commonly studied systems in decapod crustaceans. Neuromodulators are locally or hormonally released neuropeptides and amines that change the output patterns of CPGs like the STNS and CG to allow behavioral flexibility. We have hypothesized that neuromodulation provides a substrate for the evolution of behavioral flexibility, and as a result, systems exhibiting more behavioral flexibility are modulated to a greater degree. To examine this hypothesis, we evaluated the extent to which the STNS and the CG are modulated in the majoid crab species Chionoecetes opilio, Libinia emarginata, and Pugettia producta. C. opilio and L. emarginata are opportunistic feeders, whereas P. producta has a highly specialized kelp diet. We predicted that opportunistic feeding crabs that chew and process a wide variety of food types would exhibit greater STNS neuromodulatory capacity than those with a specialized diet. The STNS of L. emarginata and C. opilio responded to the seven endogenous neuromodulators oxotremorine, dopamine, CabTrp Ia, CCAP, myosuppressin, proctolin, and RPCH, whereas the STNS of P. producta only responded to proctolin, oxotremorine, myosuppressin, RPCH (25% of the time), variably to dopamine, and not at all to CabTrp and CCAP. Because P. producta, L. emarginata, and C. opilio all belong to the Majoidea superfamily, their primary distinctions are their feeding habits. For this reason, we further predicted that there would be no relationship between diet and modulatory capacity in the cardiac ganglion (CG) of the neurogenic heart. This would suggest that a lack of STNS modulatory capacity in P. producta relative to L. emarginata and C. opilio is specific to evolved foregut function. Whole-heart recordings from P. producta indicated that, unlike the STNS, the CG responds to CabTrp and CCAP. P. producta hearts also responded to oxotremorine and inconsistently to dopamine and proctolin. The CG of C. opilio was modulated by CabTrp, CCAP, dopamine, proctolin, myosuppressin, and oxotremorine, but not RPCH. The CG of L. emarginata responded to CCAP, and inconsistently to CabTrp, dopamine, and proctolin, but not to myosuppressin, RPCH, and surprisingly oxotremorine. Although cardiac responses were not identical between species, opportunistic and specialist feeders responded more similarly to the modulators tested in the heart than in the STNS. Notably, P. producta responded to each modulator in a similar manner to C. opilio and/or L. emarginata. However, L. emarginata’s surprising lack of cardiac response to oxotremorine suggests that phylogenetic closeness may not control for differences in CG and STNS function between species. Nevertheless, sample sizes of all three species were quite small, and individual differences lead to inconsistencies in the data. As a result, sample size must be enlarged to draw firm conclusions.
“I felt so untrustworthy of my ability to get pregnant”: Women’s Embodied Uncertainties and Decisions to Become Pregnant
Date: 2020-01-01
Creator: Theodora K. Hurley
Access: Open access
- This paper identifies “embodied uncertainties”—possibilities of aging and infertility lodged within the body—as informing women’s conceptualizations of their reproductive bodies and their decisions about and approaches to getting pregnant. Using data from semi-structured interviews with a small sample of highly educated, professional, white women who had given birth within 18 months prior, this paper argues that (bio)medicalized risk discourses and neoliberal logics of responsible choice-making lodge uncertainty and the possibility of failure within women’s reproductive bodies. As they attempt to reconcile childbearing with professional and financial constraints, women may identify their bodies as laden with embodied uncertainties and may subsequently adopt strategies for becoming pregnant that seek to mitigate those embodied uncertainties, such as by trying to conceive before feeling completely ready for a pregnancy. Ultimately, (bio)medicalization and neoliberalism have transformed reproductive aging and infertility into individualized concerns and foreclosed recognition of the institutional failures that create conflicts of aging, careers, and childbearing in women’s lives.
Spatially variable syn- and post-orogenic exhumation of the Appalachian Mountains from apatite and zircon (U-Th)/He thermochronology
Date: 2020-01-01
Creator: Luke Coughtry Basler
Access: Open access
- We present zircon and apatite (U-Th)/He (ZHe, closure temperature = 150-200ºC; AHe, closure temperature = 45-80ºC) results from two study regions in the Appalachians Mountains to investigate the timing, rates, and spatial trends of exhumation during Alleghanian orogenesis, Atlantic rifting, and post-rift passive margin conditions. Within West Virginia and Virginia, 10 ZHe dates along an across-orogen transect display an eastward younging trend, from ~425 million years (Ma) in the western Appalachian Plateau province, to ~250-300 Ma in the central Valley-Ridge fold-thrust belt, and 163 ± 29 Ma in the eastern Piedmont. Inverse thermal modeling of ZHe data using external geologic constraints indicates: (1) Pre-depositional cooling signatures within Pennsylvanian Appalachian Plateau rocks, suggesting provenance from recycled Taconic or Acadian basin strata, (2) Rapid Alleghanian (250-300 Ma) cooling in the Valley and Ridge province, indicating syn-orogenic uplift and exhumation, followed by a protracted period of stable syn-rift thermal conditions from ~250-150 Ma, and (3) Rapid rift-induced cooling in the Piedmont province, likely caused by rift-flank uplift and the post-rift lessening of the geothermal gradient. Within the Northern Appalachians of Vermont, four metamorphic samples yield averaged AHe dates of 100-120 Ma. Inverse thermal modeling indicates stable thermal conditions from 90 Ma to the present, limiting cooling driven by the recently recognized Northern Appalachian lithospheric thermal anomaly to < 20ºC. Modeling also indicates steady mid-Cretaceous (120-90 Ma) cooling (70 to 30ºC) coeval with passage over the Great Meteor Hotspot, although cooling rates are slower than would be expected during hotspot-induced thermal doming.
Tradition et Nouveauté: Une étude du baccalauréat et de la réforme Blanquer
Date: 2020-01-01
Creator: Fiona Carey
Access: Open access
- The baccalauréat exam has played a significant role in the lives of French high schoolers for more than two centuries. Not only does the exam determine a student’s eligibility for university, it is a long-standing national tradition and an important aspect of French identity. The baccalauréat consists of a core curriculum and a choice of specialties, all of which prepare students for the exams that they will take in their last two years of high school. In 2018, Minister of Education Jean-Michel Blanquer announced a reform to the baccalauréat that would drastically alter the content and structure of the exam. Blanquer’s reform offers students a wider variety of specialties and in doing so hopes to eliminate the supposed hierarchies which have historically valued sciences over other subject matters. This reform revolutionizes the system while simultaneously remaining deeply rooted in tradition. While Blanquer’s reform introduces changes to the core curriculum and an entirely new list of specialties, it preserves other aspects of the French education system, particularly the mandatory study of philosophy. This thesis examines the contrasting novelty and tradition of Blanquer’s baccalauréat. In order to understand the intent and implications of his reform, this thesis studies a series of historic reforms, provides a detailed explanation of Blanquer’s changes, and finally discusses a selection of anonymous survey responses concerning its potential impacts. In discussing these survey responses, I highlight three main themes: (1) hierarchies and freedom of choice, (2) collectivity and individuality, and (3) the role of nationalism in the baccalauréat.
They Used to Be Castles Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Lily Anna Fullam
Access: Access restricted to the Bowdoin Community
From “This Revolution is Neither Communist nor Capitalist!” to “Long Live the Socialist Revolution:” The Deterioration of U.S.-Cuban Relations from 1958-1961
Date: 2023-01-01
Creator: Julia Lyne
Access: Open access
- This thesis studies the deterioration of U.S.-Cuban relations from 1958-1961. Mainly drawing from primary sources from the National Archives, it seeks to answer and understand how and why relations deteriorated so rapidly. It pushes against the common belief that U.S.-Cuban relations were doomed from the start, instead highlighting in Chapter One Fidel Castro’s rise to power (and Fulgencio Batista’s fall from power) and revealing that the U.S. government was not entirely against Castro’s seizure of power. Chapter Two explores Castro’s first year in power and the (futile) attempts made by both governments to keep relations alive. Finally, it closes with the destruction of official and unofficial relations, suggesting that President Eisenhower’s covert approval of the invasion of the Bay of Pigs marked the covert ending to political relations as well as rising economic and political tensions due to an incompatibility of demand and interest in the sugar and oil industries. Ultimately, this thesis suggests that it was not just a matter of communism that led to the destruction of U.S.-Cuban relations at the time; instead, it was because of compounding effects of other various other economic and political factors and incompatibilities, such as the sugar and oil industries, public and political slandering and attacks from both sides, and an increasing acceptance of the Soviet Union and its supporters. This analysis does not seek to argue against the influence of communism in its entirety; rather, it aims to highlight and nuance the contributing factors to this deterioration.
Properties of Slicing Conditions for Charged Black Holes
Date: 2023-01-01
Creator: Sean E. Li
Access: Open access
- We consider an earlier analysis by Baumgarte and de Oliveira (2022) of static Bona-Massó slices of stationary, nonrotating, uncharged black holes, represented by Schwarzschild spacetimes, and generalize that approach to Reissner-Nordström (RN) spacetimes, representing stationary, nonrotating black holes that carry a nonzero charge. This charge is parametrized by the charge-to-mass ratio λ ≡ Q/M, where M is the black-hole mass and the charge Q may represent electrical charge or act as a placeholder for extensions of general relativity. We use a height-function approach to construct time-independent, spherically symmetric slices that satisfy a so-called Bona-Massó slicing condition. We compute quantities such as critical points and profiles of geometric quantities for several different versions of the Bona-Massó slicing condition. In some cases we do this analytically, while in others we use numerical root-finding to solve quartic equations. We conclude that in the extremal limit as λ → 1, all slices that we consider approach a unique slice that is independent of the chosen Bona-Massó condition. We then study dynamical, i.e. time-dependent, Bona-Massó slices by analytically predicting the qualitative behavior of the central lapse, i.e. the lapse at the black-hole puncture, for a particular slice that Alcubierre (1997) proposed to mitigate gauge shocks. These shock-avoiding slices are a viable alternative to the very common so-called 1 + log slices but exhibit different behavior in dynamical simulations. We use a perturbation of the radial coordinate at the location of the puncture to recover approximately harmonic late-time oscillations of the central lapse that Baumgarte and Hilditch (2022) observed in numerical simulations.
Structural and methodological factors influencing the sorption of alkylpyridiniums to aluminosilicates Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Seamus Frey
Access: Access restricted to the Bowdoin Community
The Influence of Polymers on the Solubility of Flufenamic Acid and Mefenamic Acid Cocrystals This record is embargoed.
- Embargo End Date: 2027-05-16
Date: 2024-01-01
Creator: Morgan Adams
Access: Embargoed
The French Official Mistress: Fashioning Female Political Power in the Ancien Régime
Date: 2024-01-01
Creator: Samantha Brown
Access: Open access
- This thesis focuses on the French official mistress as a position of unofficial female political power under the French monarchy from the 16th to the 18th century. Centering on three case studies – Diane de Poitiers, Madame de Maintenon, and Madame de Pompadour – this thesis argues that the role of the official mistress extended beyond sexual companion to advisor, negotiator, diplomat, artistic patron, and cultural trendsetter. By taking a deep look at the epistolary and artistic record of these three official mistresses from across France’s modern history, the extent of their autonomy and political maneuvering becomes clear in the tactics they used to project and solidify their power. Diane de Poitiers, Madame de Maintenon, and Madame de Pompadour all existed in unique contexts of the French court and constructed their own methods of fulfilling the role of the official mistress, revealing both changes in the monarchy and their impacts upon it. Notably, the ways in which they projected identity through self-fashioning resulted in a reflection of this image back onto the monarch, expanding the extent of their impact on the monarchy. In striving to understand the political reality of women in France under Salic law and today, the position of maîtresse-en-titre is a crucial framework to recognize the significance of female power structures at court and in the monarchy, and the degree to which women were able to shape these structures themselves.
Examining the Effect of Aromatic Substituents in Peptoid Catalysts of Stereoselective Trifluoromethylation Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2024-01-01
Creator: Daniel Chi
Access: Access restricted to the Bowdoin Community
The Evangelical Ethic and the Spirit of Conspiracy Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Jackson David Lakowsky Hansen
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Una Comprensione Computazionale della Psiche Emotiva e Ordine nelle Ballate del Decameron: Stilometria e Elaborazione del Linguaggio Naturale
Date: 2023-01-01
Creator: Nothando Khumalo
Access: Open access
- The present thesis, written in Italian, explores the emotional psyche and narrative order embedded within the ballads of the Decameron, a renowned literary masterpiece by Giovanni Boccaccio. Leveraging the advancements in stylometry and natural language processing techniques, this research aims to convince medieval Italian literature scholars to produce more on scholarship of the ballads and uncover the intricate patterns of human emotions and narrative organization in the ballads. The study begins by establishing a comprehensive corpus of ballads from the Decameron, utilizing digital libraries and text repositories. Subsequently, using stylometric analysis, the research examines the linguistic and stylistic features that distinguish the brigata’s ballads, focusing on elements such as vocabulary, syntax, and rhyme scheme. These analyses enable the identification of authorial patterns, shedding light on the emotional expressions and narrative techniques employed by Boccaccio. A natural language processing model was used to predict authorship of the ballads using each of the brigata’s novelle as training data. The findings of this research contribute to a deeper understanding of the emotional and narrative purpose of the Decameron's ballads. Results of stylometric analysis allowed for new characterization of Panfilo’s ballad as sad and revealed how similarity in the emotional psyches of the brigata transcends gender. These novel perspectives allowed for unique literary analysis of the ballads. Accurate prediction of ballad authorship demonstrates that ballads fit into the narrative structure of the Decameron and restore order in each of the ten days.
Design, Fabrication, and Evaluation of Surface Acoustic Wave Resonators on ST-X Quartz Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Angela McKenzie
Access: Access restricted to the Bowdoin Community
Development of a Schiff base Synthetic Platform for 8-phenyliminonaphthol Photoacids Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Ibrahim G. Saleh
Access: Access restricted to the Bowdoin Community
Synthesis of N-Heterocyclic Carbene Complexes of Coinage Metals and Their Application in the Activation of Hydrogen
Date: 2024-01-01
Creator: Maryam Akramova
Access: Open access
- The main cause of the ongoing global climate crisis is the emission of greenhouse gases, and current climate reports emphasize the need to transition to low-emission renewable energy sources. Urgently needed are methods for storing renewable energy, such as synthetic fuels like hydrogen (H2) gas; however, a challenge to the widespread implementation of hydrogen fuel is its low volumetric energy density. This thesis describes an effort to synthesize a catalyst that takes advantage of hard-soft acid-base (HSAB) mismatches to activate H2 and facilitate its reaction with CO2 to form hydrocarbon fuels, thereby providing a sustainable means of storing renewable energy in high-density carbon-neutral fuels. The catalyst design features an exceptionally bulky N-heterocyclic carbene (NHC) ligand known as IPr** (3-Bis[2,6-bis[bis(4-tert-butylphenyl)methyl]-4-methylphenyl]-1H-imidazol-3-ium chloride), a coinage metal acting as a soft acid, and a hard base such as an alkoxide ion. Herein is reported a modified synthetic route of IPr**, along with its metalation with silver, and preliminary results of the addition of an alkoxide base. The ligand and its complex with silver are structurally characterized by nuclear magnetic resonance (NMR) spectroscopy. Further work is needed to complete the characterization of IPr**-supported HSAB mismatch complexes and investigate their potential to activate H2.
From Homer to the Roman Empire: The Reception of Music in Antiquity Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Augustine Segger
Access: Access restricted to the Bowdoin Community
A Quadtree-Based, Multi-Resolution Algorithm for Computing Viewsheds on Grid Terrains Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Lily Caroline Smith
Access: Access restricted to the Bowdoin Community
Functional redundancy of a non-native foundation species (eelgrass, Zostera japonica) across intertidal stress gradients
Date: 2023-01-01
Creator: S. Maria Garcia
Access: Open access
- Non-native species foundation species can alter ecosystems in both positive and negative ways. The creation of habitat can be beneficial to native species when they provide a limiting resource or in a stressful environment. Yet this creation of habitat can also be detrimental by replacing native species and/or facilitating the presence of more non-native species. In Willapa Bay, WA, a non-native foundation species, Zostera japonica, co-exists with the native foundation species Zostera marina. Zostera japonica persists at the higher intertidal in monocultures, the two species overlap in the mid intertidal, and Z. marina persists in monocultures in the low intertidal. Epifaunal invertebrates, the organisms that live on eelgrass blades, connect eelgrass to higher trophic levels. Through a series of transplants and removals, I used this zonation pattern to ask if the two species can fulfill a similar functional role in respect to epifaunal invertebrates (functional redundancy), and if this was due to the identity of the foundation species or a response to the stress gradient of the intertidal. My results suggest that the epifaunal invertebrate community is responding more to the physiological stress gradient, and the functional redundancy of the two species depends on the location they are found. Z. japonica is expanding the range of vegetated habitat into to the physiologically stressful high zone, which supports a different community. This experiment highlights that the impacts of non- native species are highly localized and that abiotic and biotic factors are important to trophic interactions.