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.

Institutional differences and the development of entrepreneurial ventures: A comparison of the venture capital industries in Latin America and Asia

Abstract: This paper examines how differences in distinct institutional clusters of countries impact on the vital entrepreneurial activity of venture capital, and how individuals, organizations, and their collective action in turn shape those institutions. The focus on venture capital offers researchers the opportunity to view an industry that comes from a common root, with strong and consistent traditions, in which to examine how the differing institutional settings impact on behaviors in different markets, and how the institutions themselves may change in these settings. We also focus on emerging economies, since such economies offer a natural laboratory to study the impact of institutional change. Specifically, this paper employs an institutional theory perspective to examine venture capital in two regions of the world that form institutional clusters of countries – Latin America and Asia. It is found that the venture capital industry exhibits a strong consistency across many dimensions; yet institutions in these two distinct settings result in significant differences in industry practice. Therefore this research is able to contribute to both empirical and theoretical understanding of emerging economies, institutions in those environments, and venture capital.

Policy Iterations on the Hamilton–Jacobi–Isaacs Equation for $H_{\infty}$ State Feedback Control With Input Saturation

Abstract: An Hinfin suboptimal state feedback controller for constrained input systems is derived using the Hamilton-Jacobi-Isaacs (HJI) equation of a corresponding zero-sum game that uses a special quasi-norm to encode the constraints on the input. The unique saddle point in feedback strategy form is derived. Using policy iterations on both players, the HJI equation is broken into a sequence of differential equations linear in the cost for which closed-form solutions are easier to obtain. Policy iterations on the disturbance are shown to converge to the available storage function of the associated L2-gain dissipative dynamics. The resulting constrained optimal control feedback strategy has the largest domain of validity within which L2-performance for a given gamma is guaranteed

Tracing Chemical Evolution Over The Extent Of The Milky Way's Disk With Apogee Red Clump Stars

Abstract: We employ the first two years of data from the near-infrared, high-resolution SDSS-III/APOGEE spectroscopic survey to investigate the distribution of metallicity and α-element abundances of stars over a large part of the Milky Way disk. Using a sample of ≈10, 000 kinematically unbiased red-clump stars with ∼5% distance accuracy as tracers, the [α/Fe] versus [Fe/H] distribution of this sample exhibits a bimodality in [α/Fe] at intermediate metallicities, –0.9 < [Fe/H] <–0.2, but at higher metallicities ([Fe/H] ∼+0.2) the two sequences smoothly merge. We investigate the effects of the APOGEE selection function and volume filling fraction and find that these have little qualitative impact on the α-element abundance patterns. The described abundance pattern is found throughout the range 5 < R < 11 kpc and 0 < |Z| < 2 kpc across the Galaxy. The [α/Fe] trend of the high-α sequence is surprisingly constant throughout the Galaxy, with little variation from region to region (∼10%). Using simple galactic chemical evolution models, we derive an average star-formation efficiency (SFE) in the high-α sequence of ∼4.5 × 10{sup –10} yr{sup –1}, which is quite close to the nearly constant value found in molecular-gas-dominated regions of nearby spirals. This result suggests that the earlymore » evolution of the Milky Way disk was characterized by stars that shared a similar star-formation history and were formed in a well-mixed, turbulent, and molecular-dominated ISM with a gas consumption timescale (SFE{sup –1}) of ∼2 Gyr. Finally, while the two α-element sequences in the inner Galaxy can be explained by a single chemical evolutionary track, this cannot hold in the outer Galaxy, requiring, instead, a mix of two or more populations with distinct enrichment histories.« less