Outside the Wall: Hydrodynamics of Type I Supernovae Interacting with a Partially Swept-Up Circumstellar Medium

Explaining the observed diversity of supernovae (SNe) and the physics of explosion requires knowledge of their progenitor stars, which can be obtained by constraining the circumstellar medium (CSM). Models of the SN ejecta colliding with CSM are necessary to infer the structure of the CSM and tie it back to a progenitor model. Recent SNe I revealed CSM concentrated at a distance $r\sim10^16$ cm, for which models of SN interaction are extremely limited. In this paper, we assume the concentrated region is a "wall" representing swept-up material, and unswept material lies outside the wall. We simulate one-dimensional hydrodynamics of SNe Ia & Ib impacting 300 unique CSM configurations using RT1D, which captures the Rayleigh-Taylor instability. We find that the density ratio between the wall and ejecta -- denoted $A_0$ or "wall height" -- is key, and higher walls deviate more from self-similar evolution. Functional fits accounting for $A_0$ are presented for the forward shock radius evolution. We show that higher walls have more degeneracy between CSM properties in the deceleration parameter, slower shocks, deeper-probing reverse shocks, slower shocked ejecta, less ejecta mass than CSM in the shock, and more mixing of ejecta into the CSM at early times. We analyze observations of SN 2014C (Type Ib) and suggest that it had a moderately high wall ($10 < A_0 < 200$) and wind-like outer CSM. We also postulate an alternate interpretation for the radio data of SN 2014C, that the radio rise occurs in the wind rather than the wall. Finally, we find that hydrodynamic measurements at very late times cannot distinguish the presence of a wall, except perhaps as an anomalously wide shock region.Comment: 17 pages, 13 figures, accepted to Ap

The Relationship Between Future Orientation, Social Support and GPA

Future orientation (FO) is broadly defined as one’s perception of one’s future. It has been shown to act as a protective factor for adolescents regarding substance abuse, risky behavior, and internalizing problems, as well as promoting greater academic success. Most FO research has focused on children or adolescents, leaving a gap for young adults. Similarly, social support (SS) has been shown to act as a protective factor and promote positive mental health and academic outcomes. FO develops and shapes itself in accordance with an individual’s social context, including SS, making it valuable to study the two variables together. This study examines FO in college students and investigates the mediating effect of FO and SS on GPA. Participants were recruited through social media and data were collected through an anonymous online survey. The results indicate higher FO positively correlated with higher overall SS and GPAs; however, SS from a special person had a significant negative relationship with student’s GPA scores after accounting for the variance in FO and overall SS. A possible explanation for this could be the type of SS received from those special others and the likely distraction they impose for the student’s school work. Implications could include school resource centers drawing attention to these findings to increase awareness in students of how their FO and different sources of SS could be affecting their academic performance

Against the Wind: Radio Light Curves of Type Ia Supernovae Interacting with Low-Density Circumstellar Shells

For decades, a wide variety of observations spanning the radio through optical and on to the x-ray have attempted to uncover signs of type Ia supernovae (SNe Ia) interacting with a circumstellar medium (CSM). The goal of these studies is to constrain the nature of the hypothesized SN Ia mass-donor companion. A continuous CSM is typically assumed when interpreting observations of interaction. However, while such models have been successfully applied to core-collapse SNe, the assumption of continuity may not be accurate for SNe Ia, as shells of CSM could be formed by pre-supernova eruptions (novae). In this work, we model the interaction of SNe with a spherical, low density, finite-extent CSM and create a suite of synthetic radio synchrotron light curves. We find that CSM shells produce sharply peaked light curves, and identify a fiducial set of models that all obey a common evolution and can be used to generate radio light curves for interaction with an arbitrary shell. The relations obeyed by the fiducial models can be used to deduce CSM properties from radio observations; we demonstrate this by applying them to the non-detections of SN 2011fe and SN 2014J. Finally, we explore a multiple shell CSM configuration and describe its more complicated dynamics and resultant radio light curves.Comment: 15 pages, 11 figures, ApJ accepte

Ursinus Dance Program: American College Dance Association Conference, March 4-7, 2020

Ten students and two faculty members of the UC Dance Program attended the Mid-Atlantic North regional conference of the American College Dance Association (ACDA) from March 4-7, 2020, at the University of Maryland, at College Park, MD. While at the conference, students performed in two dance works, participated in dance classes, and networked with dancers in peer institutions. A highlight of the event was the selection of Visiting Dance Professor Bailey Anderson’s dance, Ridiculous Rigor: Past, Present, and Possible, for the Gala performance. Included in this document are descriptions of the Student Achievement in Research and Creativity Committee Grants awarded to the students, the ACDA classes and informal concerts they attended, as well as student and faculty responses to the conference

A Proposal for Geothermal Heating & Cooling at the University of Richmond

Ground source heat pumps (GSHPs) offer a more efficient and environmentally responsible alternative to traditional heating and cooling systems. Using the earth’s constant subsurface ground temperatures to generate heating and cooling, GSHPs allow for a decrease in fossil fuel dependence and greenhouse gas emissions. Higher education institutions, such as the University of Richmond, have a responsibility to model sustainability for their students when expanding and developing their campuses. Environmental, educational, and economic factors must be evaluated when considering new and replacement heat and energy installations. The viability of a GSHP installation on the University of Richmond’s campus should weigh current costs versus future benefits. To investigate the potential benefits of a GSHP installation on campus, the study employs both archival research and expert interviews to seek a well-rounded evaluation of the implications of geothermal energy on the University of Richmond campus. In addition to environmental incentives and economic benefits, the study explores various social and educational benefits also associated with a GSHP installation on campus. Paper prepared for the Environmental Studies Senior Seminar/Geography Capstone. Faculty Advisor: Dr. David Salisbur

Brain connectivity Patterns Dissociate action of specific Acupressure Treatments in Fatigued Breast cancer survivors

Funding This work was supported by grants R01 CA151445 and 2UL1 TR000433-06 from the National Institutes of Health. The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. We thank the expert assistance by Dr. Bradley Foerster in acquisition of 1H-MRS and fMRI data.Peer reviewedPublisher PD

CITAR LOS RENGLONES CINEMATOGRÁFICOS EN LA CONVERSACIÓN: ¿QUÉ, POR QUÉ, Y CÓMO?

Although media are known to impact affect, attitudes, behavior, and physiological indicators, no research has examined the very common but long-ignored behavior of quoting lines from movies in conversation. The primary goal of the present exploratory studies was to observe the emotions, reasons, and behaviors associated with movie quoting, and compare predicted accuracy with actual accuracy. Questionnaires were administered to two samples of 478 young adult university students. Results showed that 100% quoted movies, primarily comedies (about 70%), in conversation. They did so primarily in order to amuse themselves and others and reported little to no effort necessary to remember the lines. Lines were quoted completely or almost completely accurately around 90% of the time, and the intended hearers were usually others who had seen the film, with quoters seldom surprised at others’ reactions. Results were interpreted in light of Bandura’s (2002) theory of observational learning and its four components.Aunque los medios tienen un impacto significativo sobre las emociones, las actitudes, el comportamiento, y las medidas fisiológicas, ninguna investigación ha examinado un hecho muy usual como lo es el citar renglones cinematográficos en conversaciones cotidianas. La meta principal de la investigación actual fue medir las emociones, razones, y el comportamiento asociado a la citación de los renglones cinematográficos, y para comparar la exactitud predicha con la verdadera exactitud. Se administraron 478 cuestionarios a una muestra de estudiantes universitarios adultos jóvenes. Los resultados mostraron que el100% de los mismos citaron renglones cinematográficos, principalmente provenientes de comedias (70%) tanto para divertirse como para divertir a otros. Refirieron que recordar los renglones les requería poco o ningún esfuerzo y citaron a los mismos textualmente o casi textualmente en aproximadamente 90% de los casos. Quienes recepcionaban los mensajes habían visto la película y quienes los citaban no se mostraron sorprendidos por la respuesta de los receptores. Los resultados fueron interpretados a la luz de la Teoría de Bandura (2002) sobre el Aprendizaje Observacional y sus cuatro componentes

PTF11kx: A Type Ia Supernova with Hydrogen Emission Persisting After 3.5 Years

The optical transient PTF11kx exhibited both the characteristic spectral features of Type Ia supernovae (SNe Ia) and the signature of ejecta interacting with circumstellar material (CSM) containing hydrogen, indicating the presence of a nondegenerate companion. We present an optical spectrum at $1342$ days after peak from Keck Observatory, in which the broad component of H$\alpha$ emission persists with a similar profile as in early-time observations. We also present $Spitzer$ IRAC detections obtained $1237$ and $1818$ days after peak, and an upper limit from $HST$ ultraviolet imaging at $2133$ days. We interpret our late-time observations in context with published results - and reinterpret the early-time observations - in order to constrain the CSM's physical parameters and compare to theoretical predictions for recurrent nova systems. We find that the CSM's radial extent may be several times the distance between the star and the CSM's inner edge, and that the CSM column density may be two orders of magnitude lower than previous estimates. We show that the H$\alpha$ luminosity decline is similar to other SNe with CSM interaction, and demonstrate how our infrared photometry is evidence for newly formed, collisionally heated dust. We create a model for PTF11kx's late-time CSM interaction and find that X-ray reprocessing by photoionization and recombination cannot reproduce the observed H$\alpha$ luminosity, suggesting that the X-rays are thermalized and that H$\alpha$ radiates from collisional excitation. Finally, we discuss the implications of our results regarding the progenitor scenario and the geometric properties of the CSM for the PTF11kx system.Comment: 15 pages, 8 figures, 3 tables; submitted to Ap

IMU Validation Apparatus for Human Joints

ME450 Capstone Design and Manufacturing Experience: Fall 2020Inertial measurement units (IMUs) are small sensor packs that include accelerometers, gyroscopes, and magnetometers that are used to conduct movement analysis outside of a laboratory setting. IMUs use an integration process to determine absolute orientation and location of the object they are attached to, so error in their output is vulnerable to discrepancies from the effects of long-term data collection. Additional error can also be introduced through magnetic interference with the magnetometer readings. To combat this, calibration and post-processing algorithms can be made to adjust for these measurement errors, but ground truth angle data is needed to quantify their performance. This report outlines the requirements, specifications, evaluated concepts, verification methods, and developed solution for a device that is capable of measuring ground truth angles for comparison with angles derived from different IMU algorithms.Dr. Stephen Cain, Mechanical Engineering, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/164441/1/IMU_Validation_Apparatus_for_Human_Joints.pd