An Intermediate-Age α-Rich Galactic Population Beyond the Solar Neighborhood

Understanding the chemical history of the Galaxy is essential for developing theories and models for our Galaxy's formation history. I expanded on the results of previous work studying the relationship between chemical composition and age in the Kepler field using a new sample of red giant stars that were observed during NASA's K2 mission. This sample of stars that I used is distributed along 3 different lines of sight and reaches much further into the Galaxy than the Kepler field does. Therefore, analysis of these K2 fields allows us to see whether the composition and age trends that are observed in the solar neighborhood are also true everywhere else. Current theory suggests that the trends in the Kepler field should be true at large, as the composition of the interstellar medium at a given point in the Galaxy's history should primarily be dependent on when Type Ia and core-collapse supernova begin to go off. I selected the targets used in this analysis based on the availability of APOGEE DR16 spectra and of masses derived from the asteroseismic parameters in the K2 Galactic Archaeology Project Data Release 2. To do this analysis, I wrote a program that finds ages for individual stars by interpolating within a grid created from a set of stellar evolutionary tracks that were generated based on theoretical stellar models. This program returns the main sequence lifetime of a star provided its mass and chemical composition. I have been able to recover the age trends that were found for stars in the Kepler field while also showing that, by considering a star's alpha enhancement, this method for finding ages is an improvement over methods used in previous literature as it corrects underestimates of the ages of low-mass stars. When applied to the stars in the K2 fields, I have not recovered this trend, and instead have identified a population of stars rich in alpha elements with intermediate ages (6-9 billion years). The existence of this population is very hard to explain with our current models of Galaxy formation.No embargoAcademic Major: Astronomy and Astrophysic

Dialogical Dasein: Heidegger on "Being-with," "Discourse," and "Solicitude"

In this paper I shall show how Heidegger’s notions of Dasein’s “Being-with” (Mitsein), “discourse” (Rede), and “solicitude” (Fursorge) illustrate how he has a conception of the dialogical in Being and Time. There are at least three advantages to proposing that Heidegger is a dialogist in Being and Time. First, this paradigm offers an alternative, and more perspicuous, vocabulary for describing the discursive nature of Dasein’s Being-in-the-world as a Being-with others. Second, it provides a better way of recognizing and understanding the normative dimensions of “solicitude.” And third, it helps to underscore the ineliminable sociality of Dasein’s understanding of itself and of others, such that its identity remains social even in the seemingly individualizing initial moment of becoming authentic

Link groups of 4-manifolds

The notion of a Bing cell is introduced, and it is used to define invariants, link groups, of 4-manifolds. Bing cells combine some features of both surfaces and 4-dimensional handlebodies, and the link group \lambda(M) measures certain aspects of the handle structure of a 4-manifold M. This group is a quotient of the fundamental group, and examples of manifolds are given with \pi_1(M) not equal to \lambda(M). The main construction of the paper is a generalization of the Milnor group, which is used to formulate an obstruction to embeddability of Bing cells into 4-space. Applications to the A-B slice problem and to the structure of topological arbiters are discussed.Comment: 34 pages, 7 figures. v.3: minor phrasing change

Spaceflight performance of several types of silicon solar cells on the LIPS 3 satellite

Results from exposure of several types of Solarex silicon cells to a space environment for nearly two years on the LIPS 3 satellite are presented. Experiments include standard thickness (10 mil) cells with and without back surface fields, and ultrathin (2 mil) cells also with and without back surface fields. A comparison between a widely used coverslide adhesive, DC 93-500 and a potential alternate is also presented. The major findings from the data are that the 2 mil cells without a back surface field show the smallest normalized short circuit current degradation and that the 10 mil back surface field cells show the greatest absolute power output for the radiation exposures and temperatures encountered. The new encapsulant (McGhan Nusil CV-2500) exhibits a degradation comparable to DC 93-500. A comparison is made with each of the cell types in this experiment with expectations based on JPL Radiation Handbook data

Automatic Renal Segmentation in DCE-MRI using Convolutional Neural Networks

Kidney function evaluation using dynamic contrast-enhanced MRI (DCE-MRI) images could help in diagnosis and treatment of kidney diseases of children. Automatic segmentation of renal parenchyma is an important step in this process. In this paper, we propose a time and memory efficient fully automated segmentation method which achieves high segmentation accuracy with running time in the order of seconds in both normal kidneys and kidneys with hydronephrosis. The proposed method is based on a cascaded application of two 3D convolutional neural networks that employs spatial and temporal information at the same time in order to learn the tasks of localization and segmentation of kidneys, respectively. Segmentation performance is evaluated on both normal and abnormal kidneys with varying levels of hydronephrosis. We achieved a mean dice coefficient of 91.4 and 83.6 for normal and abnormal kidneys of pediatric patients, respectively

Arena production for educational dramatics.

Thesis (M.A.)--Boston Universit

Rowling in the Deep: J.K. Rowling, Transphobia, and Reactionary Fandom

J. K. Rowling, the bestselling author of the popular young adult book series Harry Potter, has recently been recognized for her transphobic comments on Twitter. As of this writing, the author has not come forward to apologize for two separate instances of polemical tweets that targeted the transgender community. An exhaustive literature review reveals numerous studies of socially-mediated transphobia and its effects on fans, but not in the case of Rowling. Based on a discourse analysis of fans and anti-fans\u27 9,000+ tweets from August of 2020 to January of 2023, as scraped and culled from Rowling\u27s Twitter page, this study argues that the author missed at least two opportunities to meaningfully engage with fans and anti-fans on her page and, as such, contributed to a larger culture of apathy around mediated representations of transphobia. The larger issue at stake is how public figures like Rowling engage in questions related to transgender rights and equality in popular discourse, a question that holds larger implications for cultural politics in the present day