Showing 3501 - 3550 of 5831 Items
Improving Energy Efficiency through Compiler Optimizations
Date: 2021-01-01
Creator: Jack Beckitt-Marshall
Access: Open access
- Abstract--- Energy efficiency is becoming increasingly important for computation, especially in the context of the current climate crisis. The aim of this experiment was to see if the compiler could reduce energy usage without rewriting programs themselves. The experimental setup consisted of compiling programs using the Clang compiler using a set of compiler flags, and then measuring energy usage and execution time on an AMD Ryzen processor. Three experiments were performed: a random exploration of compiler flags, utilization of SIMD, as well as benchmarking real world applications. It was found that the compiler was able to reduce execution time, especially when optimizing for the specific architecture, to a degree that depends on the program being compiled. Faster execution time tended to correlate with reduced energy usage as well, further suggesting that optimizing programs for speed and architecture is the most effective way of decreasing their overall energy usage.
Instability in a Time-Modulated Lattice This record is embargoed.
- Embargo End Date: 2025-05-19
Date: 2022-01-01
Creator: Evelyn Wallace
Access: Embargoed
Assessing the Accuracy of Quantum Monte Carlo Pseudopotentials for CO2 Capture in Metal Organic Frameworks
Date: 2021-01-01
Creator: Chloe Renfro
Access: Open access
- As global emissions of CO2 and other greenhouse gases rises, global warming persists as an imminent threat to the environment and every day lives. To reduce greenhouse gas emissions in the atmosphere, there is a need to design materials to separate and capture the different gasses. Current gas capturing technologies lack efficiency and have extensive energy costs. A class of materials for CO2 capture is Molecular Organic Frameworks (MOFs). In order for a MOF to be efficient for this type of separation, the MOF needs to be able to selectively bind to the gas, while also not suffering a high energy cost to remove the gas and reuse the material. Computationally calculated binding energies are used to determine the usefulness of a MOF at capture and separation of a certain gas. Each computational method has its advantages and limitations. In this work, diffusion quantum Monte Carlo is being explored. This paper focuses on the accuracy of recently developed pseudopotentials for DMC use. These pseudopotentials have been tested on smaller molecules but have not been systematically tested for systems such as MOFs. Results from a DMC calculation of Zn-MOF-74 show a binding energy of -18.02 kJ/mol with an error bound of 16.74 kJ/mol. In order to assess the accuracy of the DMC results for binding energies of this magnitude the uncertainty need to be reduced, a subject of ongoing work.
Investigating the Effects of Mixed Solvents on the Excited State Proton Transfer Mechanisms of 8-Amino-2-naphthol This record is embargoed.
- Embargo End Date: 2027-05-19
Date: 2022-01-01
Creator: Alexander Avrom Kreines
Access: Embargoed
A Conscious Image of Liberation: Euskadi Ta Askatasuna (ETA) in the Late Franco Regime, Through the Lens of the Press
Date: 2022-01-01
Creator: Sebastian de Lasa
Access: Open access
- The rise of Euskadi Ta Askatasuna (ETA) in the early 1970s coincided with the rise of national liberation movements across Europe, which largely were inspired by notable examples of resistance throughout the Global South in the decades prior. ETA’s growth over this period, and in the years prior, was heavily dependent on the image created of the organziation in the local, domestic, and international press, including through documents distributed by the group itself. By comparing ETA’s external presence to the group’s internal strife, it becomes clear that ETA made efforts to align itself with the popular revolutionary language of the period. The group took advantage of, and aimed to create press spectacles, in attempts to manipulate its public image. However, the discrepancy between the group’s public image and internal dissolution became apparent as the group pursued more violent acts in the goal of Basque liberation.
Identification of MPKs Involved in the Wall Associated Kinase Regulated Stress Response in Arabidopsis thaliana Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2013-05-01
Creator: Patrick J Lariviere
Access: Access restricted to the Bowdoin Community
Characterizing Toll Receptors in the Mediterranean Cricket Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2022-01-01
Creator: Warsameh Bulhan
Access: Access restricted to the Bowdoin Community
Unraveling Paradise: Colonialism and Disguise in German Language Literature
Date: 2022-01-01
Creator: Brigita Kant
Access: Open access
- For centuries, the Pacific Islands have been disguised by Europeans through the trope of “island paradise." Despite Europe’s role in bringing colonization and racial oppression to Oceania, the dominant narrative has been that Pacific Islanders lead simple lives, untouched from the complicated aspects of the “modern world.” This narrative has enabled White outsiders to fantasize about the Pacific Islands as a place for personal denial of Western social conventions, simultaneously allowing White European men to fetishize and possess Pacific Island culture and identity. My honors project will closely examine three fictional German language texts- Haimotochare (1819), Der Papalagi (1920), and Imperium (2012)- centered around the exploration German colonial involvement in Pacific Islands. My analysis of these texts will allow for the understanding of how the false narrative of “island paradise” came to be, how it has been embraced and weaponized, and what it means for both German and Pacific Islander post-colonial identity.
Outlier Detection in Energy Datasets
Date: 2022-01-01
Creator: Stephen Crawford
Access: Open access
- In the past decade, numerous datasets have been released with the explicit goal of furthering non-intrusive load monitoring research (NILM). NILM is an energy measurement strategy that seeks to disaggregate building-scale loads. Disaggregation attempts to turn the energy consumption of a building into its constituent appliances. NILM algorithms require representative real-world measurements which has led institutions to publish and share their own datasets. NILM algorithms are designed, trained, and tested using the data presented in a small number of these NILM datasets. Many of the datasets contain arbitrarily selected devices. Likewise, the datasets themselves report aggregate load information from building(s) which are similarly selected arbitrarily. This raises the question of the representativeness of the datasets themselves as well as the algorithms based on their reports. One way to judge the representativeness of NILM datasets is to look for the presence of outliers in these datasets. This paper presents a novel method of identifying outlier devices from NILM datasets. With this identification process, it becomes possible to mitigate and measure the impact of outliers. This represents an important consideration to the long-term deployment of NILM algorithms.
"Possessive gentleness": Insecure Attachments in American Literature
Date: 2022-01-01
Creator: Ella Pearl Crabtree
Access: Open access
- “‘Possessive Gentleness’: Insecure Attachments in American Literature” applies psychological attachment theory to works of American Literature. Each novel examined—Uncle Tom’s Cabin (1851), Dred: A Tale of the Dismal Swamp (1856), and The Minister’s Wooing (1859) by Harriet Beecher Stowe, The Third Generation (1954) by Chester Himes, and The Bluest Eye (1970) by Toni Morrison—describes the forces behind insecure attachment relationships between child characters and their caregivers. The first chapter of this project focuses on Stowe’s anti-slavery novels. It argues that the institution of slavery is in conflict with Christianity in these works, because it impedes disinterestedly benevolent mothering and disrupts secure attachments. The second chapter analyzes The Third Generation, and suggests that colorism in the black community is the cause of insecure attachments in Himes’ work. The third and final chapter examines The Bluest Eye, and presents sympathy, as embodied by the novel’s narrator, as a potential remedy for insecure parent-child attachments. Together, these texts elucidate how societal forces (e.g. colorism, poverty) intrude upon the family structure and destabilize parent-child attachments. Optimistically, however, they also suggest that improved parent-child attachments might function as a vehicle of broader social change.
Forests as Fuel? An Investigation of Biomass’ Role in a Just Energy Transition
Date: 2022-01-01
Creator: Brianna Cunliffe
Access: Open access
- Although wood pellet biomass corporations frame their recent rapid growth as a victory for “green energy”, troubling evidence of their adverse impacts on climate and environmental justice calls for rigorous investigation of these claims. Contextualizing biomass within the envirotechnical regimes that have created industrial ‘sacrifice zones’ in BIPOC low-income communities in the US South, this paper recharacterizes it as an innovation within oppressive regimes. It further critiques carbon accounting frameworks that designate biomass as renewable despite its greater emissions per capita than coal and carbon debts created by deforestation that could take centuries to rectify. Biomass pellet production plants, cited disproportionately in environmental justice communities, also emit serious and often under-reported amounts of pollutants including PM 2.5, VOCs, and HAPs, linked to higher rates of chronic illness and premature death in impacted communities. The current regulatory paradigm guarantees neither distributive nor procedural justice. Ethnographic research including participant-observation, interviews, and site visits revealed that community members felt that regulatory bodies serve corporations above vulnerable citizens, that their voices were not valued in public hearings or by elected officials, and that the pollution, dishonesty, and ecological harms plants bring far outweighs their meagre economic benefits. Communities enact robust resistance to biomass as both a global climate threat and a local injustice. This paper traces how coalitions connecting intersectional grassroots activist networks to larger advocacy organizations are achieving victories on the ground and in the court of public opinion, and the lessons this synergy holds for the endeavor of a truly just transition.
Characterization of the ELMO2 Protein that Mediates Cell Adhesion in Arabidopsis thaliana
Date: 2022-01-01
Creator: Devaki Rajiv
Access: Open access
- The binding of adjacent cells to one another, or cell adhesion, is critical for the growth and development of multicellular organisms. In plant cells, much evidence suggests that the amount and modification of pectin in the cell wall largely determines how well cell adhesion occurs. ELMO1 is a Golgi protein involved in pectin-mediated cellular adhesion, and mutations in ELMO1 lead to disrupted cell organization in Arabidopsis. ELMO1 is predicted to be a scaffold for pectin biosynthesis enzymes, and thus its absence leads to the adhesion-defective phenotype of elmo1-/- plants. There are four other ELMO homologues (ELMO2,3,4 and 5) which remain to be characterized as to their function and role in cell adhesion. This thesis focuses on the characterization of ELMO2, which has 79% amino acid similarity with ELMO1. A genetic analysis that evaluated elmo2 double mutants revealed that ELMO2 and ELMO1 have redundant functions. elmo1-/-/2-/- double mutants, but not elmo2-/- or elmo1-/- single mutants, have reduced tensile strengths. While elmo1-/- phenotypes are most pronounced in liquid media, they are partially rescued by growth on agar, suggesting a role of turgor in maintaining cell adhesion. Like ELMO1, ELMO2-GFP colocalizes with Golgi markers. The results suggest that like ELMO1, ELMO2 also functions as a scaffold for pectin biosynthesis enzymes in the Golgi.
Investigating the Role of Helicobacter pylori Glycan Biosynthesis in Modulating Host Immune Cell Recognition Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Katharine Barrett
Access: Access restricted to the Bowdoin Community
Errandsphere 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: Aida Muratoglu
Access: Access restricted to the Bowdoin Community
Pheromones enhance somatosensory processing in newt brains through a vasotocin-dependent mechanism
Date: 2008-07-22
Creator: R. R. Thompson, P. S. Dickinson, J. D. Rose, K. A. Dakin, G. M., Civiello, A. Segerdahl, R. Bartlett
Access: Open access
- We tested whether the sex pheromones that stimulate courtship clasping in male roughskin newts do so, at least in part, by amplifying the somatosensory signals that directly trigger the motor pattern associated with clasping and, if so, whether that amplification is dependent on endogenous vasotocin (VT). Female olfactory stimuli increased the number of action potentials recorded in the medulla of males in response to tactile stimulation of the cloaca, which triggers the clasp motor reflex, as well as to tactile stimulation of the snout and hindlimb. That enhancement was blocked by exposing the medulla to a V1a receptor antagonist before pheromone exposure. However, the antagonist did not affect medullary responses to tactile stimuli in the absence of pheromone exposure, suggesting that pheromones amplify somatosensory signals by inducing endogenous VT release. The ability of VT to couple sensory systems together in response to social stimulation could allow this peptide to induce variable behavioural outcomes, depending on the immediate context of the social interaction and thus on the nature of the associated stimuli that are amplified. If widespread in vertebrates, this mechanism could account for some of the behavioural variability associated with this and related peptides both within and across species. © 2008 The Royal Society.
Long-term maintenance of channel distribution in a central pattern generator neuron by neuromodulatory inputs revealed by decentralization in organ culture
Date: 2001-09-15
Creator: Adi Mizrahi, Patsy S. Dickinson, Peter Kloppenburg, Valerie Fénelon, Deborah J., Baro, Ronald M. Harris-Warrick, Pierre Meyrand, John Simmers
Access: Open access
- Organotypic cultures of the lobster (Homarus gammarus) stomatogastric nervous system (STNS) were used to assess changes in membrane properties of neurons of the pyloric motor pattern-generating network in the long-term absence of neuromodulatory inputs to the stomatogastric ganglion (STG). Specifically, we investigated decentralization-induced changes in the distribution and density of the transient outward current, IA, which is encoded within the STG by the shal gene and plays an important role in shaping rhythmic bursting of pyloric neurons. Using an antibody against lobster shal K+ channels, we found shal immunoreactivity in the membranes of neuritic processes, but not somata, of STG neurons in 5 d cultured STNS with intact modulatory inputs. However, in 5 d decentralized STG, shal immunoreactivity was still seen in primary neurites but was likewise present in a subset of STG somata. Among the neurons displaying this altered shal localization was the pyloric dilator (PD) neuron, which remained rhythmically active in 5 d decentralized STG. Two-electrode voltage clamp was used to compare IA in synaptically isolated PD neurons in long-term decentralized STG and nondecentralized controls. Although the voltage dependence and kinetics of IA changed little with decentralization, the maximal conductance of IA in PD neurons increased by 43.4%. This increase was consistent with the decentralization-induced increase in shal protein expression, indicating an alteration in the density and distribution of functional A-channels. Our results suggest that, in addition to the short-term regulation of network function, modulatory inputs may also play a role, either directly or indirectly, in controlling channel number and distribution, thereby maintaining the biophysical character of neuronal targets on a long-term basis.
Quantification of dendritic and axonal growth after injury to the auditory system of the adult cricket gryllus bimaculatus
Date: 2013-09-27
Creator: Alexandra Pfister, Amy Johnson, Olaf Ellers, Hadley W. Horch
Access: Open access
- Dendrite and axon growth and branching during development are regulated by a complex set of intracellular and external signals. However, the cues that maintain or influence adult neuronal morphology are less well understood. Injury and deafferentation tend to have negative effects on adult nervous systems. An interesting example of injury-induced compensatory growth is seen in the cricket, Gryllus bimaculatus. After unilateral loss of an ear in the adult cricket, auditory neurons within the central nervous system (CNS) sprout to compensate for the injury. Specifically, after being deafferented, ascending neurons (AN-1 and AN-2) send dendrites across the midline of the prothoracic ganglion where they receive input from auditory afferents that project through the contralateral auditory nerve (N5). Deafferentation also triggers contralateral N5 axonal growth. In this study, we quantified AN dendritic and N5 axonal growth at 30 h, as well as at 3, 5, 7, 14, and 20 days after deafferentation in adult crickets. Significant differences in the rates of dendritic growth between males and females were noted. In females, dendritic growth rates were non-linear; a rapid burst of dendritic extension in the first few days was followed by a plateau reached at 3 days after deafferentation. In males, however, dendritic growth rates were linear, with dendrites growing steadily over time and reaching lengths, on average, twice as long as in females. On the other hand, rates of N5 axonal growth showed no significant sexual dimorphism and were linear. Within each animal, the growth rates of dendrites and axons were not correlated, indicating that independent factors likely influence dendritic and axonal growth in response to injury in this system. Our findings provide a basis for future study of the cellular features that allow differing dendrite and axon growth patterns as well as sexually dimorphic dendritic growth in response to deafferentation. © 2013 Pfister, Johnson, Ellers and Horch.
Economic Costs of Elevated Public Debt Levels During Banking-Crisis Recessions
Date: 2021-01-01
Creator: Gavin T Shilling
Access: Open access
- The Great Recession of 2007 and 2008 exposed the risks of excessive borrowing. We learned the essential economic principle that greater leverage harbors greater risk. Although this global economic contraction was driven primarily by booming private credit expansion, economically inefficient incentives in the public sector, such as short-term reelection concerns, may lead politicians to engage in rash deficit- financed, fiscal spending. The primary purpose of this research is to assess the economic costs of heightened, preexisting government leverage on real economic outcomes during recessionary periods, focusing on both banking and non-banking crisis recessions. In both advanced economies and emerging economies, this study confirms that banking recessions are associated with more severe economic contractions and more persistent output declines than normal recessions. In advanced economies, GDP recovers quickly and strongly with expansionary and supportive fiscal policy during low debt recessions, even with depressed private investment. While GDP recovers slowly and weakly with less expansionary fiscal policy during high debt recessions, even with strong private investment. Thus, the social marginal benefit of public sector investment exceeds the social marginal benefit of private sector investment in advanced economies. In emerging economies, GDP recovers quickly and strongly with strong private investment during high debt recessions, even with weak fiscal spending. While GDP recovers slowly and weakly with depressed private investment during low debt recessions, even with expansionary and supportive fiscal policy. Thus, the social marginal benefit of private sector investment exceeds the social marginal benefit of public sector investment in emerging economies.
Bowdoin College Catalogue (1961-1962)
Date: 1962-01-01
Access: Open access
- Bowdoin College Bulletin no. 342
Seasons Without Borders: the Ali Smith Quartet
Date: 2021-01-01
Creator: Claire M Burns
Access: Open access
- This project considers how the novels of contemporary Scottish author Ali Smith work to destabilize traditional constructions of temporal, formal, national, and gender borders. The motifs of the border and the border identity have been thematically pervasive in Scottish literary history, as reflected in the recurrence of the Scottish split identity. This thesis explores how the borders that have become essential to the construction of Scottish national literature, often relying on binaristic categorizations, have been disestablished in the contemporary era. Ali Smith’s novels, particularly the novels of her seasonal quartet, introduce forms and figures that highlight the instability of many of these borders, challenging fixed representations of the border identity. Through this focus on Scotland, Smith constructs a template for a consideration of national identity beyond the boundaries of Scotland, extending toward a more global sensibility.
AMGSEFLamide, a member of a broadly conserved peptide family, modulates multiple neural networks in Homarus americanus
Date: 2019-01-01
Creator: Patsy S. Dickinson, Evyn S. Dickinson, Emily R. Oleisky, Cindy D. Rivera, Meredith E., Stanhope, Elizabeth A. Stemmler, J. Joe Hull, Andrew E. Christie
Access: Open access
- Recent genomic/transcriptomic studies have identified a novel peptide family whose members share the carboxyl terminal sequence –GSEFLamide. However, the presence/identity of the predicted isoforms of this peptide group have yet to be confirmed biochemically, and no physiological function has yet been ascribed to any member of this peptide family. To determine the extent to which GSEFLamides are conserved within the Arthropoda, we searched publicly accessible databases for genomic/transcriptomic evidence of their presence. GSEFLamides appear to be highly conserved within the Arthropoda, with the possible exception of the Insecta, in which sequence evidence was limited to the more basal orders. One crustacean in which GSEFLamides have been predicted using transcriptomics is the lobster, Homarus americanus. Expression of the previously published transcriptome-derived sequences was confirmed by reverse transcription (RT)-PCR of brain and eyestalk ganglia cDNAs; mass spectral analyses confirmed the presence of all six of the predicted GSEFLamide isoforms – IGSEFLamide, MGSEFLamide, AMGSEFLamide, VMGSEFLamide, ALGSEFLamide and AVGSEFLamide – in H. americanus brain extracts. AMGSEFLamide, of which there are multiple copies in the cloned transcripts, was the most abundant isoform detected in the brain. Because the GSEFLamides are present in the lobster nervous system, we hypothesized that they might function as neuromodulators, as is common for neuropeptides. We thus asked whether AMGSEFLamide modulates the rhythmic outputs of the cardiac ganglion and the stomatogastric ganglion. Physiological recordings showed that AMGSEFLamide potently modulates the motor patterns produced by both ganglia, suggesting that the GSEFLamides may serve as important and conserved modulators of rhythmic motor activity in arthropods.
Characterization of the mature form of a β-defensin-like peptide, Hoa-D1, in the lobster Homarus americanus
Date: 2018-09-01
Creator: Giap H. Vu, Daniel Do, Cindy D. Rivera, Patsy S. Dickinson, Andrew E., Christie, Elizabeth A. Stemmler
Access: Open access
- We report on the characterization of the native form of an American lobster, Homarus americanus, β-defensin-like putative antimicrobial peptide, H. americanus defensin 1 (Hoa-D1), sequenced employing top-down and bottom-up peptidomic strategies using a sensitive, chip-based nanoLC-QTOF-MS/MS instrument. The sequence of Hoa-D1 was determined by mass spectrometry; it was found to contain three disulfide bonds and an amidated C-terminus. The sequence was further validated by searching publicly-accessible H. americanus expressed sequence tag (EST) and transcriptome shotgun assembly (TSA) datasets. Hoa-D1, SYVRScSSNGGDcVYRcYGNIINGAcSGSRVccRSGGGYamide (with c representing a cysteine participating in a disulfide bond), was shown to be related to β-defensin-like peptides previously reported from Panulirus japonicas and Panulirus argus. We found Hoa-D1 in H. americanus hemolymph, hemocytes, the supraoesophageal ganglion (brain), eyestalk ganglia, and pericardial organ extracts, as well as in the plasma of some hemolymph samples. Using discontinuous density gradient separations, we fractionatated hemocytes and localized Hoa-D1 to hemocyte sub-populations. While Hoa-D1 was detected in semigranulocytes and granulocytes using conventional proteomic strategies for analysis, the direct analysis of cell lysates exposed evidence of Hoa-D1 processing, including truncation of the C-terminal tyrosine residue, in the granulocytes, but not semigranulocytes. These measurements demonstrate the insights regarding post-translational modifications and peptide processing that can be revealed through the MS analysis of intact peptides. The identification of Hoa-D1 as a widely-distributed peptide in the lobster suggests the possibility that it may be pleiotropic, with functions in addition to its proposed role as an antimicrobial molecule in the innate immune system.
Brutal Encounters: Primitivity, Politics, and the Postmodern Revolution
Date: 2021-01-01
Creator: Archer Thomas
Access: Open access
- The switch from late modernism to postmodernism in Western aesthetic theory and criticism took place in the mid-to-late 20th century, radically changing the face of cultural criticism. Much has been written on how postmodernism broke from modernism, but what factors paved its way in the decades following the Second World War? This paper argues that postmodernism represents both a reaction to and a necessary evolution of late modernism, specifically as it manifests in architecture, politics, and the politics of architecture. It focuses on the crisis of confidence among Western left-wing circles following the upheaval of the Second World War and posits that, because of this upheaval, primitivism came to dominate the epistemology of a renewed modernism led by figures such as Clement Greenberg, Reyner Banham, and the practitioners of “the New Brutalism.” The paper then explores how the Western left-wing reaction to developments like decolonization and postwar modernization challenged primitivity’s newfound importance, resulting in a shift towards a “postmodern populism” in aesthetics and politics by the 1960s as described by Jean Baudrillard, Fredric Jameson, Robert Venturi, and Reyner Banham.
Bowdoin College Catalogue (1968-1969)
Date: 1969-01-01
Access: Open access
- Bowdoin College Bulletin no. 370
Characterization of plexinA and two distinct semaphorin1a transcripts in the developing and adult cricket Gryllus bimaculatus
Date: 2020-03-01
Creator: Hadley W. Horch, Sara B. Spicer, Isabel I.C. Low, Colby T. Joncas, Eleanor D., Quenzer, Hikmah Okoya, Lisa M. Ledwidge, Harrison P. Fisher
Access: Open access
- Guidance cues act during development to guide growth cones to their proper targets in both the central and peripheral nervous systems. Experiments in many species indicate that guidance molecules also play important roles after development, though less is understood about their functions in the adult. The Semaphorin family of guidance cues, signaling through Plexin receptors, influences the development of both axons and dendrites in invertebrates. Semaphorin functions have been extensively explored in Drosophila melanogaster and some other Dipteran species, but little is known about their function in hemimetabolous insects. Here, we characterize sema1a and plexA in the cricket Gryllus bimaculatus. In fact, we found two distinct predicted Sema1a proteins in this species, Sema1a.1 and Sema1a.2, which shared only 48% identity at the amino acid level. We include a phylogenetic analysis that predicted that many other insect species, both holometabolous and hemimetabolous, express two Sema1a proteins as well. Finally, we used in situ hybridization to show that sema1a.1 and sema1a.2 expression patterns were spatially distinct in the embryo, and both roughly overlap with plexA. All three transcripts were also expressed in the adult brain, mainly in the mushroom bodies, though sema1a.2 was expressed most robustly. sema1a.2 was also expressed strongly in the adult thoracic ganglia while sema1a.1 was only weakly expressed and plexA was undetectable.
The Mérida Initiative and the Violence of Transnational Criminal Organizations in Mexico
Date: 2021-01-01
Creator: Brianna Madison Canning
Access: Open access
- Organized crime related violence in Mexico remains at unprecedented levels despite decades of effort and billions of dollars spent attempting to weaken Transnational Criminal Organizations (TCOs) through the Mérida Initiative (MI): a bilateral security partnership established in October 2007 between US President George W. Bush and Mexican President Felipe Calderón. The MI sought to combat TCOs (often called cartels), their drug trafficking operations, and their networks of corruption. However, since then TCOs have expanded their businesses beyond drug trafficking, and they have adopted violent practices that target civilians. Extortion, torture, murder, and human trafficking have become common as TCOs look to other illicit markets to make up for losses in drug profits, and to signal strength to their opponents. More specifically, the homicide rate in Mexico increased by more than 100% between 2007 and 2008, aligning with the creation of the initiative designed to have the opposite effect. However, case study research into the violence in Ciudad Juárez and Tijuana determined that the MI was not actually implemented until mid-2009 because of bureaucratic delays, meaning it did not impact the initial spike in homicides in Mexico in 2008. Instead, the violence starting in 2008 is a result of changing dynamics between and within TCOs, as they adapted to survive and maintain control of resources. By supporting the Mexican government’s drug war efforts over the next several years, the Mérida Initiative became one of many complex domestic and international factors that ultimately contributed to extreme levels of violence in Mexico.
Photochemistry of Cyano-Substituted 8-Amino-2-Naphthol This record is embargoed.
- Embargo End Date: 2026-05-20
Date: 2021-01-01
Creator: Jialin Xie
Access: Embargoed
Can Small Donations Have Big Consequences? Candidate Ideology, Small Donations, and Election Results in the 2016 and 2018 Congressional Cycles
Date: 2021-01-01
Creator: Michael Borecki
Access: Open access
- Small donors have provided an increased share of total campaign contributions in the 2016, 2018, and 2020 U.S. federal election cycles, including about $3 billion of the $14.4 billion raised in 2020. Campaign funding is still dominated by an influential set of large donors, but small donations may be the basis for an effective response to the disproportionate amount of “big money” in politics. This study investigates whether candidates who are more extreme perform better with small donors, and then examines the impact of small donations and overall funding on election results. These analyses were performed using linear sum-of-squares regression models. The results in Chapter 2 show that candidates who are more politically-extreme receive more of their funding from small donations, but perform worse in general elections when fundraising is equal. Chapter 3 shows that small donations do not have an impact on candidate performance in general elections more generally, but candidates who outraise their opponent also outperform relative to the district’s partisan lean. However, that effect disappears when looking only at elections decided by less than 10 percent of the vote. These results suggest that small donors are more likely to support candidates who are more politically polarized, but the effects of small donors on the makeup of Congress is marginal at best, at least as far as general election outcomes are concerned. The project concludes by considering reform proposals that seek to broaden the pool of Americans who donate small sums to political candidates.
How do long-term above-ground biomass dynamics vary between different forest stand types at Harvard Forest?
Date: 2023-01-01
Creator: Maya Y. Chandar-Kouba
Access: Open access
- Monitoring forest carbon storage is necessary in accurately modelling the global carbon cycle. In the Northeast, terrestrial forests represent a major carbon sink with above-ground biomass (AGB) accounting for 40% of stored forest carbon. Therefore, understanding how AGB varies spatiotemporally is essential in predicting future carbon storage. Repeated measurements in permanent, long-term plots provide an opportunity to examine how carbon stored in AGB is changing over time. I used 29 years of data from the Harvard Forest Environmental Monitoring Systems (HF EMS) Site to determine how stand composition, intrinsic factors, and extrinsic environmental factors influenced rates of carbon storage in AGB over time. Using a partition around medoids (PAM) clustering method, I separated the 34 ground plots at the EMS stand into their respective stand types. I found that each stand type at the HF EMS plots accumulates carbon at consistent rates throughout the study period, although rates of carbon accumulation between stands were significantly different. Red Pine stands experience a rapid decline in biomass in 2018 due to the introduction of the Southern Pine Beetle. Across all stand types, sporadic mortality events determine variations in yearly rates of carbon accumulation, although this has little significant influence on total AGB accumulation. Leaf area index (LAI) and foliar N contents have no effect on growth increments. Extrinsic environmental variables had mixed effects on growth and mortality, highlighting the complexities of predicting forest carbon storage under changing climate conditions.
Rhythmic behaviors: Understanding neuromodulation at the neuromuscular level
Date: 2023-01-01
Creator: Kenneth Garcia
Access: Open access
- Neuromodulation allows for the flexibility of neural circuit dynamics and the outputs they produce. Studies of the stomatogastric nervous system (STNS) have expanded our knowledge on the actions of neuromodulators, small molecules that most often activate G-protein coupled receptors and reconfigure circuit activity and composition. In these systems, modulation has been found to occur at every level, from sensory-motor coupling to neuromuscular transmission (Harris-Warrick and Marder 1991). Neuromodulators have complex effects on motor output; they can alter the firing of individual neurons while also modulating muscle properties, neuromuscular transmission, and sensory neuron response to muscle activity (Fort et al. 2004). We investigated this further by recording the motor output produced by the gastric mill rhythm of the lobster STNS under neuromodulator conditions. How is this neuromuscular system as a whole modulated to produce motor flexibility? We hypothesized that these neuromodulators act on individual receptors of component neurons of central pattern generator (CPG)-effector system themselves and at the periphery, coordinately altering muscle contraction by altering all levels of the crustacean neuromuscular system. Application of NRNFLRFamide, RPCH, oxotremorine, and proctolin to the gastric mill 4 (gm4) muscles of the Cancer crab showed that neuromodulators that have been found to have variable, yet significant effects on the activity of the neurons of the STNS directly alter the activity of the gm4 muscles as well, suggesting that coordination of peripheral actions and direct neuronal modulation regulates patterned motor output.
Neptune City This record is embargoed.
- Embargo End Date: 2026-05-18
Date: 2023-01-01
Creator: Lily Randall
Access: Embargoed
A multifaceted analysis of Semaphorin-induced neuroplasticity in the nervous system of Gryllus bimaculatus Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2028-06-01
Date: 2023-01-01
Creator: Ean Lev Small
Access: Access restricted to the Bowdoin Community
Invisible Ailments: A Collection
Date: 2023-01-01
Creator: Jane L. Godiner
Access: Open access
- "Invisible Ailments" is a collection of short stories that trace the depth, breath, and sweeping range of lived experiences of people struggling with mental illness. While it is a work of fiction, the people in these stories might feel eerily familiar — to your friends, your family members, your loved ones, or, if you're brave enough to admit it, yourself.