Transgenre Theses & Dissertations

Lightning talk for Symposium on Electronic Theses and Dissertations (ETD) at Purdue University on May 23, 2019

Reduced convergence and the local smoothness parameter: bridging two different descriptions of weak lensing amplification

Weak gravitational lensing due to the inhomogeneous matter distribution in the universe is an important systematic uncertainty in the use of standard candles in cosmology. There are two different descriptions of weak lensing amplification, one uses a local smoothness parameter $\tilde{\alpha}$, the other uses reduced convergence $\eta= 1+ \kappa/|\kappa_{min}|$ (where $\kappa$ is convergence). The $\tilde{\alpha}$ description involves Dyer-Roeder distance $D_A(\tilde{\alpha}|z)$ ($\tilde{\alpha}=1$ corresponds to a smooth universe); it is simple and convenient, and has been used by the community to illustrate the effect of weak lensing on point sources such as type Ia supernovae. Wang (1999) has shown that the $\tilde{\alpha}$ description can be made realistic by allowing $\tilde{\alpha}$ to be a local variable, the local smoothness parameter. The $\eta$ description has been used by Wang, Holz, & Munshi (2002) to derive a universal probability distribution (UPDF) for weak lensing amplification. In this paper, we bridge the two different descriptions of weak lensing amplification by relating the reduced convergence $\eta$ and the local smoothness parameter $\tilde{\alpha}$. We give the variance of $\tilde{\alpha}$ in terms of the matter power spectrum, thus providing a quantitative guidance to the use of Dyer-Roeder distances in illustrating the effect of weak lensing. The by-products of this work include a corrected definition of the reduced convergence, and simple and accurate analytical expressions for $D_A(\tilde{\alpha}|z)$. Our results should be very useful in studying the weak lensing of standard candles.Comment: Revised and expanded version. ApJ accepte

Online Education: Transferring Personal Experiences to Professional Development

In this paper, we discuss how one candidate’s experience as she participated an online mathematics specialist program bolstered her confidence and ability to provide online professional development for her teachers. We include personal accounts by the mathematics specialist program instructors, the mathematics specialist candidate, and an elementary school teacher to illustrate how the experience of completing online graduate courses led to the candidate providing online learning opportunities for teachers. In particular, we highlight the importance of building relationships and using high-quality mathematical tasks in both the online preparation program and the online professional development. This case study provides evidence that exposure to online learning environments as a learner can help lower the barrier of entry for planning and providing online learning experiences as a teacher

Observational signatures of the weak lensing magnification of supernovae

Due to the deflection of light by density fluctuations along the line of sight, weak lensing is an unavoidable systematic uncertainty in the use of type Ia supernovae (SNe Ia) as cosmological distance indicators. We derive the expected weak lensing signatures of SNe Ia by convolving the intrinsic distribution in SN Ia peak luminosity with magnification distributions of point sources. We analyze current SN Ia data, and find marginal evidence for weak lensing effects. The statistics is poor because of the small number of observed SNe Ia. Future observational data will allow unambiguous detection of the weak lensing effect of SNe Ia. The observational signatures of weak lensing of SNe Ia that we have derived provide useful templates with which future data can be compared.Comment: Including 4 color figures. Expanded and modified version. JCAP accepte

Indian health conditions.

This volume is a compendium of scholarly analyses of the health conditions that together constitute most of the illness borne by American Indians and Alaska Natives. Topics include; health intervention; cancer; cardiovascular diseases; diabetes; digestive system diseases; infant mortality; infectious diseases; maternal health; mental health and mental illness; musculosketetal system disease; oral disease; end-stage renal disease; respiratory diseases; violence; substance abuse; and accidental injuries. This publication was developed in 1986 and although, the data are several years old, much of the analyses and recommendations are still relevant today. It also serves as an important historical or reference document for the Indian Health Service. Each analysis provides an overview of a particular health condition as it affects the IHS service population nationwide and suggests, recommendations regarding the steps that IHS can take to reduce and eventually eliminate the described health problems

Institutional legacies and HRM: similarities and differences in HRM practices in Portugal and Mozambique

This is a study of institutional change and continuity, comparing the trajectories followed by Mozambique and its formal colonial power Portugal in HRM, based on two surveys of firm level practices. The colonial power sought to extend the institutions of the metropole in the closing years of its rule, and despite all the adjustments and shocks that have accompanied Mozambique’s post-independence years, the country continues to retain institutional features and associated practices from the past. This suggests that there is a post-colonial impact on human resource management. The implications for HRM theory are that ambitious attempts at institutional substitution may have less dramatic effects than is commonly assumed. Indeed, we encountered remarkable similarities between the two countries in HRM practices, implying that features of supposedly fluid or less mature institutional frameworks (whether in Africa or the Mediterranean world) may be sustained for protracted periods of time, pressures to reform notwithstanding. This highlights the complexities of continuities which transcend formal rules; as post-colonial theories alert us, informal conventions and embedded discourse may result in the persistence of informal power and subordination, despite political and legal changes