Texas Christian University

About: Texas Christian University is a education organization based out in Fort Worth, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 3245 authors who have published 8258 publications receiving 282216 citations. The organization is also known as: TCU & Texas Christian University, TCU.

Extinction Maps Toward The Milky Way Bulge: Two-Dimensional And Three-Dimensional Tests With APOGEE

Abstract: Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both two-dimensional and three-dimensional extinction maps, using independent extinction measures based on a large spectroscopic sample of stars toward the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution H-band Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants toward the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, two-dimensional bulge extinction maps, and three-dimensional extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the two-dimensional and three-dimensional extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.

Being the CEO's boss: An examination of board chair orientations

Abstract: Research summary: Scholars have traditionally conceptualized board leadership as a dichotomous construct. A combined CEO and board chair position is interpreted as reflecting a more collaborative approach to corporate governance, whereas separate positions are interpreted as ensuring greater board control. I challenge this conceptualization and posit that a separate board chair can be oriented toward collaboration as well as—or in place of—control. I analyze newly available data from corporate proxy statements to identify these two board chair orientations and test competing perspectives on how they impact profitability growth in a sample of S&P 500 firms. The results indicate that board leadership is a more nuanced phenomenon than the extant literature would suggest. Managerial summary: What is the role of the board chair when not the CEO? Corporate governance experts assert the board chair's role is to monitor and control the CEO. Yet, board chairs often play another, more collaborative role. Board chairs frequently provide advice and guidance to CEOs and relieve CEOs of board leadership burdens, enabling the CEOs to focus on their primary responsibilities. In this study, I examine the effect of board chair orientations on financial performance and find that, as with separating or joining the CEO and board chair positions, the profitability implications of the selected orientation are far from universal. Board chairs must consider their firm's performance context in order to get the most out of a particular approach to being the CEO's boss. Copyright © 2016 John Wiley & Sons, Ltd.

A Review and Examination of Demographic Similarity Measures Used to Assess Relational Demography Within Groups

Abstract: Relational demography within groups, or an individual's demographic similarity to a group, is a type of cross-level theory labeled as an individual-within-the-group model. Previous researchers used...

COMPANIONS to APOGEE STARS. I. A MILKY WAY-SPANNING CATALOG of STELLAR and SUBSTELLAR COMPANION CANDIDATES and THEIR DIVERSE HOSTS

Abstract: In its three years of operation, the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed >14,000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical radial velocity precision of ∼100–200 m s−1, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Here we present initial results from a catalog of 382 of the most compelling stellar and substellar companion candidates detected by APOGEE, which orbit a variety of host stars in diverse Galactic environments. Of these, 376 have no previously known small separation companion. The distribution of companion candidates in this catalog shows evidence for an extremely truncated brown dwarf (BD) desert with a paucity of BD companions only for systems with a < 0.1–0.2 AU, with no indication of a desert at larger orbital separation. We propose a few potential explanations of this result, some which invoke this catalog’s many small separation companion candidates found orbiting evolved stars. Furthermore, 16 BD and planet candidates have been identified around metal-poor ([Fe/H] < −0.5) stars in this catalog, which may challenge the core accretion model for companions >10MJup. Finally, we find all types of companions are ubiquitous throughout the Galactic disk with candidate planetary-mass and BD companions to distances of ∼6 and ∼16 kpc, respectively.

Anticipatory Anxiety Patterns for Male and Female Public Speakers.

Abstract: In previous research, physiological and psychological anxiety patterns have been established for public speakers. In a recent study (Behnke & Sawyer, 1999) reported state and trait patterns of anticipatory anxiety for public speakers for two weeks preceding the actual presentation. In the present study, gender differences in anticipatory state anxiety and narrowband trait anxiety patterns were investigated. Significant gender‐based pattern differences were discovered with higher anxiety patterns reported by female speakers. Both female and male speaker groups exhibited the hypothesized quadratic v‐shaped pattern of mean anxiety scores for the anticipatory period. Theoretical and pedagogical implications of the findings are discussed.