Showing 191 - 200 of 564 Items
The Photocatalytic Degradation of 17α-ethynylestradiol (EE2) and Related Estrogens 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: Kevin Jairre Fleshman
Access: Access restricted to the Bowdoin Community
“Something most girls don’t do” An Ethnographic Study of Women in Extreme Sports
Date: 2022-01-01
Creator: Jacqueline Boben
Access: Open access
- Extreme sports, like skateboarding, whitewater kayaking, and skiing, have historically been male-dominated. As women’s participation in these sports grows, my research asks: how do women navigate sports spaces and cultures that have for so long been defined by men? To answer this question, I draw on ethnographic research on communities of skateboarders, whitewater kayakers and skiers conducted during the summer of 2021 in Bozeman, Montana. I found that the specific landscapes where these extreme sports take place are often conceptualized by participants as more masculine spaces. Within these spaces and communities, women participants often leverage gender performances associated with masculinity to gain entry into these male-dominated communities. Performing in more masculine ways mitigates feelings of hypervisibility, while also helping to build connections to established members of the community. More than simply fitting in, women find that these gendered performances also help them to build competence in the sport. At the same time, women are transforming skateboarding, whitewater kayaking, and skiing through their participation by creating opportunities for more dynamic and fluid gender performances.
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.
Parole lievitanti: La panificazione spirituale di S. Caterina di Bologna This record is embargoed.
- Embargo End Date: 2027-05-19
Date: 2022-01-01
Creator: Katherine Aiello McKee
Access: Embargoed
The development of begging calls in Yellow Warblers
Date: 2015-05-01
Creator: Jackson F Bloch
Access: Open access
- Nestling birds use begging calls to solicit resources from adults. Efficient transmission of calls is necessary for motivating parental feeding and outcompeting siblings. However, ambient acoustic masking and costs such as predation may influence the structure of the calls. While many interspecific comparisons of begging behavior have been made, the ontogeny of calls is understudied. In this study, Yellow Warbler (Setophaga petechia) begging calls were recorded and analyzed at different stages of nestling development to document changes in acoustic structure and gain insight into the selective forces that influence call development. Begging calls increased in peak frequency, frequency range, and amplitude during the 5-day recording period. Call duration did not change with age. Call structure did not differ between nestlings living in distinct acoustic environments. As begging calls increase in amplitude with age, perhaps due to increased food needs and competition from nestmates, nestlings may compensate for increased predation risk by increasing the peak frequency of the calls. Higher frequency calls attenuate more quickly than do low frequency calls and fall outside the frequency range of maximum hearing sensitivity for some potential predators. Previous studies on warbler begging have shown that nestlings of ground-nesting warblers, which are subject to higher rates of predation, beg at higher frequencies than do nestlings of tree-nesting warblers. This study supports the hypothesis that changes to begging call structure during development mirror the differences in call structure of species under different predation risks.
Geochemical and Stratigraphic Analysis of the Linnévatnet Sediment Record: A Study of Late Holocene Cirque Glacier Activity in Spitsbergen, Svalbard
Date: 2014-05-01
Creator: Graham Harper Edwards
Access: Open access
- Morainal and lacustrine sediments in Linnédalen, Spitsbergen, Svalbard, record the fluctuations of a glacier in a currently unglaciated mountain cirque during the Little Ice Age (LIA). This study attempts to reconstruct Late Holocene glacial activity within this cirque from geochemical, physical, and visual stratigraphic variation of the Linnévatnet lacustrine sediment record. A 57 cm lacustrine sediment core (D10.5) from Linnévatnet was analyzed at a high-resolution for variations in X-Ray Fluorescence (XRF)-measured elemental composition, spectral reflectance, and magnetic susceptibility. The visual stratigraphy was observed at a microscopic scale. An age-depth model for D10.5 is developed by extrapolating sedimentation rates from dated horizons, measured by 239+240Pu radionuclide fallout dating and chemostratigraphic enrichment of atmospheric anthropogenic pollutants. Visual stratigraphy of the sediment record indicates two periods of cirque glacier sediment delivery to Linnévatnet during the LIA (1329-1363 CE, 1816 CE-Present) and a third period of sediment delivery during the Medieval Climate Anomaly (MCA; 984-1082 CE). During non-glacial periods, stratigraphic variation in XRF-measured Ti and K appear to be associated with fluctuations in North Atlantic Oscillation (NAO)-regulated precipitation. Within the LIA glacial intervals, decadal-scale variations in sediment Ti and K geochemistry may result from advance and retreat of the cirque glacier ice-margin or fluctuations in precipitation. Stratigraphic variation in Fe content indicates complex erosional and hydrological processes associated with MCA precipitation and glacial meltwater. Stratigraphic and geochemical variations in the lacustrine record of Linnévatnet indicate that both cirque glacier activity and sediment transport in Linnédalen are more sensitive to climatological change than previously thought.
Teaching Computers to Teach Themselves: Synthesizing Training Data based on Human-Perceived Elements
Date: 2019-05-01
Creator: James Little
Access: Open access
- Isolation-Based Scene Generation (IBSG) is a process for creating synthetic datasets made to train machine learning detectors and classifiers. In this project, we formalize the IBSG process and describe the scenarios—object detection and object classification given audio or image input—in which it can be useful. We then look at the Stanford Street View House Number (SVHN) dataset and build several different IBSG training datasets based on existing SVHN data. We try to improve the compositing algorithm used to build the IBSG dataset so that models trained with synthetic data perform as well as models trained with the original SVHN training dataset. We find that the SVHN datasets that perform best are composited from isolations extracted from existing training data, leading us to suggest that IBSG be used in situations where a researcher wants to train a model with only a small amount of real, unlabeled training data.
Economic Analysis of the Critical Habitat Designation Process for Endangered and Threatened Species Under the Endangered Species Act of 1973
Date: 2022-01-01
Creator: Katherine Fosburgh
Access: Open access
- Habitat destruction is the leading cause of biodiversity loss in the US. Under the Endangered Species Act (ESA), habitat deemed essential to endangered and threatened species recovery is proposed as critical habitat (CH). CH areas are subject to regulations that could alter land development plans or increase costs. The potential economic opportunity cost created by CH regulations may lead to the exclusion of land proposed for CH designation, thereby reducing the conservation benefits of the CH rule. In this paper, I use a unique dataset collected from Federal Register (FR) documents to estimate the reduction in CH acreage from proposed to final ruling, both on the extensive and intensive margin. I find a negative relationship between the level of household income in an area proposed for CH and the probability that a CH gains acreage or maintains acreage during the establishment process. I also find some evidence that higher household income in a CH area is associated with a greater relative loss in acreage between proposal and finalization. I also find that private land proposed for CH designation is less likely to be in the final designation than federal land. Overall, my results suggest that economic considerations influence CH allocation decisions. Whether reducing the amount of private land subject to CH designations is socially efficient depends on the unknown economic benefit of private land exclusions versus the cost of biodiversity and ecosystem service loss that may result from not protecting all land deemed vital to species recovery.
Fluorescent Sugar Analogs as Probes for Bacterial Monosaccharide Uptake Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2024-01-01
Creator: Foje-Geh Robert Tendoh
Access: Access restricted to the Bowdoin Community
Using atmospheric O2 and CO2 measurements to determine the stoichiometry of photosynthesis and respiration in a temperate forest
Date: 2018-01-01
Creator: Margaret Marie Conley
Access: Open access
- The O2:CO2 exchange ratio of the terrestrial biosphere (αb) is an important parameter in carbon sink calculations, but its value is not well constrained. We investigate the stoichiometry of O2 and CO2 at Harvard Forest in Petersham, Massachusetts over a span of six years, considering the covariation of O2 and CO2 in forest air during 6-hour periods to determine an average value for the O2:CO2 exchange ratio. This approach provides a way to determine the value of αb averaged across seasonal cycles and species assemblages. Our analysis produces an overall average exchange ratio of -1.06 ± 0.01. Comparing measurements within and above the canopy and during nighttime and daytime periods, we observe that atmospheric dynamics and canopy effects produce lower exchange ratios indicative of an enhanced forest signal at the low intake and for daytime periods. We also see an increase in the exchange ratio in the winter compared to the summer that may reflect changes in plant physiological processes or contamination by a fossil fuel signal. To determine whether our observed ratio is truly representative of αb, we use a simple model to estimate the range of variability in CO2 and O2 mixing ratios expected from local influence alone and use this as a criterion to isolate periods dominated by local exchange, yielding an average summer forest exchange ratio of -1.00 ± 0.02. Our analysis provides insight into the average value and variability of αb for temperate forests for use in calculation of the land carbon sink.