Showing 541 - 550 of 583 Items
An Exploration of the Room Temperature Growth and Tuning of Cobalt Hydroxide Carbonate Morphologies and Assemblies Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2026-06-01
Date: 2023-01-01
Creator: Zubin Jay Kenkare
Access: Access restricted to the Bowdoin Community
The Current Support Theorem in Context
Date: 2023-01-01
Creator: Ethan Winters
Access: Open access
- This work builds up the theory surrounding a recent result of Erlandsson, Leininger, and Sadanand: the Current Support Theorem. This theorem states precisely when a hyperbolic cone metric on a surface is determined by the support of its Liouville current. To provide background for this theorem, we will cover hyperbolic geometry and hyperbolic surfaces more generally, cone surfaces, covering spaces of surfaces, the notion of an orbifold, and geodesic currents. A corollary to this theorem found in the original paper is discussed which asserts that a surface with more than $32(g-1)$ cone points must be rigid. We extend this result to the case that there are more than $3(g-1)$ cone points. An infinite family of cone surfaces which are not rigid and which have precisely $3(g-1)$ cone points is also provided, hence demonstrating tightness.
Mutual benefits of inducible defenses to crab predators in the blue mussel Mytilus edulis in a multi-predator environment
Date: 2021-01-01
Creator: Sophia Walton
Access: Open access
- The blue mussel Mytilus edulis alters its phenotype in species-specific ways in response to either green crab (Carcinus maenus) or sea star (Asterias sp.) predation. Previous studies have shown that only sea stars induce changes in abductor muscle morphology, while green crabs generally alter the shape and thickness of shells. In the Western Gulf of Maine, Blue mussels collected from wave protected sites with abundant green crab predators were shown to have significantly thicker shells and larger adductor muscles than mussels collected from wave exposed sites with few green crab predators. The phenotypes of mussels originating from wave-protected and high green crab abundance sites increased the handling time by A. forbesi compared to sites with low wave exposure and high green crab abundance. These results contradict the paradigm that shell thickness trades off with abductor morphology, and I propose that a likely candidate for increased energy allocation to these traits is a decrease in reproductive allocation. My results further suggest that the escalating “arms race” between invasive green crabs and blue mussels in the Western Gulf of Maine is leading to changes in the phenotypic response of mussel populations in ways that are likely impacting sea star foraging dynamics.
Promoter Choice in Transvection at the eya Gene of Drosophila melanogaster This record is embargoed.
- Embargo End Date: 2027-05-15
Date: 2024-01-01
Creator: Victoria Dunphy
Access: Embargoed
Bondi Accretion in Trumpet Geometries
Date: 2016-01-01
Creator: August J Miller
Access: Open access
- The Bondi solution, which describes the radial inflow of a gas onto a non-rotating black hole, provides a powerful test for numerical relativistic codes. However, this solution is typically derived in Schwarzschild coordinates, which are not well suited for dynamical spacetime evolutions. Instead, many current numerical relativistic codes adopt moving-puncture coordinates, which render black holes in trumpet geometries. Here we transform the Bondi solution into two different trumpet coordinate systems, both of which result in regular expressions for the fluid flow extending into the black hole interior. We also evolve these solutions numerically and demonstrate their usefulness for testing and calibrating numerical codes.
Young Authoritarians? Trends and Individual Differences in Preschoolers' Perceptions of Adult Authority
Date: 2018-05-01
Creator: Ava Alexander
Access: Open access
- Although traditional stage theories (e.g., Piaget, 1965) postulate that preschool age children are guided entirely by punishment avoidance and absolute deference to authority, more recent research suggests that their concepts of adult authority are complex and vary based on social cognitive domain and the content of the commands (e.g., Tisak, 1986). Also, although past studies have shown that the majority of children will reject adult authority in certain contexts, much individual variation between children has been observed (e.g., Laupa, 1994). The current study expanded upon past research by exposing children to multiple typical and atypical commands across domains, while also testing for individual differences based on two forms of parental authoritarianism. Results showed that children as young as four reject commands that go against established moral or conventional norms, and sometimes reject commands in the personal domain. This pattern grew stronger with age. High right-wing authoritarianism was a significant predictor of more authoritarian parenting style, and also predicted lower child support for authority in typical conventional scenarios.
Examining the Ability of Remote Sensing to Characterize Turfgrass Stress Physiology
Date: 2022-01-01
Creator: Benjamin Ross
Access: Open access
- Remote sensing of solar induced chlorophyll fluorescence (SIF) is a valuable tool in understanding the global carbon cycle. While SIF is highly correlated with photosynthesis at the ecosystem scale, the role that remote sensing of SIF can play at smaller scales is still unclear. The goal of my research was to investigate the ability of SIF to detect changes in pigmentation, photosynthesis, and energy partitioning at the grass canopy and leaf level in response to water stress and abscisic acid (ABA) hormone treatments. Both treatments immediately inhibited photosynthesis by limiting gas exchange through stomatal closure, but SIF declined gradually. Recovery of photosynthesis after alleviation of water stress was not reflected in remote measurements of SIF. I found that senescence in the tips of grasses had been driving changes in remote measurements, which affected remote measurements even when measured leaf-level gas exchange in the lower living tissue recovered. This heterogeneous senescence pattern contextualizes the disconnect between SIF and photosynthesis in stressed turfgrass.
Nuevas posibilidades para la subjetividad feminista en la literatura del Cono Sur
Date: 2022-01-01
Creator: Kate Elizabeth Tapscott
Access: Open access
- ¿Cómo es que se puede escapar verdaderamente de la opresión patriarcal? Esta investigación aborda a través de un análisis de la literatura de escritoras del Cono Sur el asunto complicado de la liberación bajo un sistema en constante mutación. En el primer capítulo, a partir de aportes teóricos de Freud, Josefina Ludmer y Homi Bhabha entre otros, analizo cuentos de Jorge Luis Borges, Silvina Ocampo, y Clarice Lispector cuyas protagonistas intentan resistir su condición de víctima con diversos grados de éxito. En el capítulo que sigue, exploro una tendencia reciente en la literatura de escritoras del Cono Sur que incorpora elementos del horror y lo gótico para desestabilizar una cosmovisión humanista y patriarcal. Incorporando la teoría de Gabriel Giorgi, Rosi Braidotti, y Julieta Yelin, investigo los efectos que los animales, los cuerpos, y la materia tienen en la expansión de la agencia feminista y discuto si ofrecen o no nuevas e inesperadas posibilidades para resistir el sistema.
"Proud Flesh and Blood": Phineas Fletcher, Gabriel Daniel, and Seventeenth-Century Theories of Embodiment
Date: 2022-01-01
Creator: Micaela Elanor Simeone
Access: Open access
- The human body was a site of discovery and redefinition in early modern Europe. This project traces the gradual arc from the mid-seventeenth century towards Cartesian notions of the body in the later part of the century through two fictions: Phineas Fletcher (1582-1650)’s The Purple Island (1633) and Gabriel Daniel (1649-1728)’s Voyage du Monde de Descartes (1690). This project views these two largely-overlooked texts as important literary works that represent the seventeenth century’s transformative debates about and explorations of the human body. I argue that Fletcher employs a dissective mode that embraces mind-body harmony while framing the human as both fragmented and whole. I then explore how Voyage du Monde de Descartes responds to an altogether different culture in the late seventeenth century, after Cartesian ideas extracted mind from body and no longer saw the body as a significant marker of humanity. I argue that Voyage ultimately reveals—through a captivating satirical fiction—how understanding Cartesian anatomy as the product of anxiety, uncertainty, and novelty helps us better see how we became motivated to transcend our bodies.
Demography of a Collapsing Aerial Insectivore Population
Date: 2017-05-01
Creator: Liam Taylor
Access: Open access
- Aerial insectivores have been declining across northeastern North America since the end of the 20th century. The mechanisms and demographic patterns of this decline are unclear. On Kent Island, New Brunswick, Canada, an isolated population of Tree Swallows (Tachycineta bicolor) collapsed between 1987 and 2010. To explore how demographic rates (i.e., survival, reproduction, and immigration) drove the population dynamics of these northeastern aerial insectivores, we combined productivity, population survey, and capture-recapture data in an integrated population model analysis. Neither consistently low juvenile survival rates, adult survival rates, nor clutch size were correlated with population growth rate across years. Alternatively, male and female immigration, hatching success, and fledging success rates were correlated with population growth rate. Because local hatching and fledging success rates cannot influence a population without local recruitment, we argue that the demography of these Tree Swallows is mainly structured by immigration. Parameter-substitution simulations revealed that overall decline was likely even if the population had avoided the worst years of demographic collapse. Breeding Bird Survey comparisons demonstrated how the Kent Island population represents both a demographic and geographical extreme at the edge of a declining region. These demographic patterns highlight the sensitivity, even to the point of local extinction, of some isolated populations to region-scale patterns in the production of potential immigrants.