Robust FDI Determinants: Bayesian Model Averaging In The Presence Of Selection Bias

The literature on Foreign Direct Investment (FDI) determinants is remarkably diverse in terms of competing theories and empirical results. We utilize Bayesian Model Averaging (BMA) to resolve the model uncertainty that surrounds the validity of the competing FDI theories. Since the structure of existing FDI data is known to induce selection bias, we extend BMA theory to HeckitBMA to address model uncertainty in the presence of selection bias. We then show that more than half of the previously suggested FDI determinants are no longer robust and highlight theories that receive support from the data. In addition, our selection approach allows us to highlight that the determinants of margins of FDI (intensive and extensive) differ profoundly in the data, while FDI theories do not usually model this aspect explicitly.

Techniques for targeted Fermi-GBM follow-up of gravitational-wave events

The Advanced LIGO and Advanced Virgo ground-based gravitational-wave detectors are projected to come online 2015-2016, reaching a final sensitivity sufficient to observe dozens of binary neutron star mergers per year by 2018. We present a fully-automated, targeted search strategy for prompt gamma-ray counterparts in offline Fermi-GBM data. The multi-detector method makes use of a detailed model response of the instrument, and benefits from time and sky location information derived from the gravitational-wave signal.Comment: 2012 Fermi Symposium proceedings - eConf C12102

Bullous hemorrhagic lichen sclerosus of the breast: a report of two cases and review of the literature

Lichen sclerosus (LS) is a chronic dermatologic condition characterized by atrophic porcelain-appearing plaques that can cause intense discomfort and eventually lead to destruction of local architecture. Lichen sclerosus most commonly arises in the anogenital area, but up to 20% of cases can present on extragenital skin. Rarely, LS can also present with hemorrhage and bullae; the mechanism by which this occurs is unknown. We report two cases of bullous hemorrhagic LS of the breast arising in 66-year-old and 77-year-old women. Bullous hemorrhagic LS of the breast is exceedingly rare, with few reported cases, and presents a diagnostic challenge to clinicians

Closure statistics in interferometric data

Interferometric visibilities, reflecting the complex correlations between signals recorded at antennas in an interferometric array, carry information about the angular structure of a distant source. While unknown antenna gains in both amplitude and phase can prevent direct interpretation of these measurements, certain combinations of visibilities called closure phases and closure amplitudes are independent of antenna gains and provide a convenient set of robust observables. However, these closure quantities have subtle noise properties and are generally both linearly and statistically dependent. These complications have obstructed the proper use of closure quantities in interferometric analysis, and they have obscured the relationship between analysis with closure quantities and other analysis techniques such as self calibration. We review the statistics of closure quantities, noting common pitfalls that arise when approaching low signal-to-noise due to the nonlinear propagation of statistical errors. We then develop a strategy for isolating and fitting to the independent degrees of freedom captured by the closure quantities through explicit construction of linearly independent sets of quantities along with their noise covariance in the Gaussian limit, valid for moderate signal-to-noise, and we demonstrate that model fits have biased posteriors when this covariance is ignored. Finally, we introduce a unified procedure for fitting to both closure information and partially calibrated visibilities, and we demonstrate both analytically and numerically the direct equivalence of inference based on closure quantities to that based on self calibration of complex visibilities with unconstrained antenna gains.Comment: 31 pages, 17 figure

Dynamical Imaging with Interferometry

By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information necessary to form an image. Conventional imaging techniques partially overcome this limitation by making the assumption that the observed cosmic source structure does not evolve over the duration of an observation, which enables VLBI networks to accumulate information as the Earth rotates and changes the projected array geometry. Although this assumption is appropriate for nearly all VLBI, it is almost certainly violated for submillimeter observations of the Galactic Center supermassive black hole, Sagittarius A* (Sgr A*), which has a gravitational timescale of only ~20 seconds and exhibits intra-hour variability. To address this challenge, we develop several techniques to reconstruct dynamical images ("movies") from interferometric data. Our techniques are applicable to both single-epoch and multi-epoch variability studies, and they are suitable for exploring many different physical processes including flaring regions, stable images with small time-dependent perturbations, steady accretion dynamics, or kinematics of relativistic jets. Moreover, dynamical imaging can be used to estimate time-averaged images from time-variable data, eliminating many spurious image artifacts that arise when using standard imaging methods. We demonstrate the effectiveness of our techniques using synthetic observations of simulated black hole systems and 7mm Very Long Baseline Array observations of M87, and we show that dynamical imaging is feasible for Event Horizon Telescope observations of Sgr A*.Comment: 16 Pages, 12 Figures, Accepted for publication in Ap

Observing---and Imaging---Active Galactic Nuclei with the Event Horizon Telescope

Originally developed to image the shadow region of the central black hole in Sagittarius A* and in the nearby galaxy M87, the Event Horizon Telescope (EHT) provides deep, very high angular resolution data on other AGN sources too. The challenges of working with EHT data have spurred the development of new image reconstruction algorithms. This work briefly reviews the status of the EHT and its utility for observing AGN sources, with emphasis on novel imaging techniques that offer the promise of better reconstructions at 1.3 mm and other wavelengths.Comment: 10 pages, proceedings contribution for Blazars through Sharp Multi-Wavelength Eyes, submitted to Galaxie

The Effect Of Problem Based Learning On Undergraduate Oral Communication Competency

Purpose:  The aim of this study was to ascertain the effect of Problem Based Learning (PBL) on student oral communication competency gains. Methods:  Eighty students from two consecutive undergraduate Kinesiology courses (Spring semesters, 2014-15) formed into 29 small groups and were studied.  Oral communication competency was assessed using a customized rubric and digital recordings of student presentations.  Changes to oral communication competency across time were tested using a dependent t-test; a < .05. Results:  Significant inter-rater agreement was found at both time points for oral communication rating, and student groups demonstrated significant oral communication gains across time.  Conclusions:  Collaborative learning was shown to improve students’ oral communication competency. Future study is required to determine the influence of student motivation and goal orientation on oral communication competency, in relation to the various phases of knowledge creation occurring within student groups.

Detection of intrinsic source structure at ~3 Schwarzschild radii with Millimeter-VLBI observations of SAGITTARIUS A*

We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in 2013 March using six VLBI stations in Hawaii, California, Arizona, and Chile. Compared to earlier observations, the addition of the APEX telescope in Chile almost doubles the longest baseline length in the array, provides additional {\it uv} coverage in the N-S direction, and leads to a spatial resolution of $\sim$30 $\mu$as ($\sim$3 Schwarzschild radii) for Sgr A*. The source is detected even at the longest baselines with visibility amplitudes of $\sim$4-13% of the total flux density. We argue that such flux densities cannot result from interstellar refractive scattering alone, but indicate the presence of compact intrinsic source structure on scales of $\sim$3 Schwarzschild radii. The measured nonzero closure phases rule out point-symmetric emission. We discuss our results in the context of simple geometric models that capture the basic characteristics and brightness distributions of disk- and jet-dominated models and show that both can reproduce the observed data. Common to these models are the brightness asymmetry, the orientation, and characteristic sizes, which are comparable to the expected size of the black hole shadow. Future 1.3 mm VLBI observations with an expanded array and better sensitivity will allow a more detailed imaging of the horizon-scale structure and bear the potential for a deep insight into the physical processes at the black hole boundary.Comment: 11 pages, 5 figures, accepted to Ap

Everybody in and nobody out : opportunities, narrative, and the radical flank in the movement for single-payer health care reform

Title from PDF of title page (University of Missouri--Columbia, viewed on August 29, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Clarence LoIncludes bibliographical references.Vita.Ph. D. University of Missouri--Columbia 2012"May 2012"In this dissertation, I analyze over twenty years of the United States Single Payer Movement. I began this analysis with the following questions in mind -- What is the Relationship between opportunity and grassroots mobilization? How do activists understand opportunity? What is the role of narrative in this process? I grounded my analysis in a feminist epistemological and methodological stance, which is rooted in the understanding that all knowledge is located and that we can learn much by privileging the voices from marginalized positions. This research involved participant observation, semi-structured interviews, and content analysis. This research has resulted in a significant contribution to social movement theory by further explicating the relationship between opportunity and grassroots opportunity. I argue that social movement actors develop understandings about the opportunities that they face through the practice of narrative. This narrative practice is an integral aspect in the process of pragmatic liberation, or the practice of liberation, through which social movement actors seek to empower themselves and a wider audience of constituents. Even during time periods in which there is less political likelihood that the movement will achieve its goals, movement activists are able to mobilize constituencies by constructing narratives of opportunity outside of the material realm. A more diverse system of narrative practice that is rooted in multiple types of opportunity facilitates greater diversity in movement mobilization.Includes bibliographical reference