University of Houston

About: University of Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23074 authors who have published 53903 publications receiving 1641968 citations.

The photopic negative response of the macaque electroretinogram: reduction by experimental glaucoma.

Abstract: PURPOSE. TO investigate the photopic flash electroretinograms (ERGs) of macaque monkeys in which visual field defects developed as a consequence of experimental glaucoma. METHODS. Unilateral experimental glaucoma was induced in 10 monkeys by argon laser treatment of the trabecular meshwork. Visual field sensitivity was assessed behaviorally by static perimetry. Photopic ERGs were recorded to brief- (^5 msec) and long-duration (200 msec) red ganzfeld flashes on a rod-suppressing blue-adapting background. Electroretinograms were recorded in four other monkeys, after intravitreal injection of tetrodotoxin (TTX; 3-8-8 /xM) to suppress action potentials of retinal ganglion and amacrine cells, and in six normal adult human subjects. RESULTS. Experimental glaucoma removed a cornea-negative response, the photopic-negative response (PhNR), from the ERG. The PhNR in control eyes was maximal approximately 60 msec after a brief flash, 100 msec after onset, and 115 msec after offset of the long-duration stimulus. The PhNR in experimental eyes was greatly reduced when the mean deviation of the visual field sensitivity was as little as —6 dB. As visual sensitivity declined further, the PhNR was reduced only slightly more. The a- and b-waves were unchanged, even when sensitivity decreased by more than 16 dB. Tetrodotoxin also selectively reduced the PhNR. The PhNR was observed in normal human ERGs. CONCLUSIONS. The cornea-negative PhNR of the photopic ERG depends on spiking activity and is reduced in experimental glaucoma when visual sensitivity losses are still mild. The PhNR most likely arises from retinal ganglion cells and their axons, but its slow timing raises the possibility that it could be mediated by glia. Regardless of the mechanism of its generation, the PhNR holds promise as an indicator of retinal function in early glaucomatous optic neuropathy. (Invest Ophthalmol Vis Sci. 1999;40:1124 -1136)

Synergy, Managerialism or Hubris? An Empirical Examination of Motives for Foreign Acquisitions of U.S. Firms

Abstract: This study examines the motives underlying foreign acquisitions of U.S. firms, estimates the extent of value creation associated with such acquisitions, and examines how total gains are shared between acquiring firms and targets. We show that the synergy hypothesis is the predominant explanation for our sample of foreign acquisitions of U.S. firms. However, the hubris hypothesis coexists with the synergy hypothesis in explaining the acquisitions in our sample that are characterized by positive total gains. The evidence is also consistent with the managerialism hypothesis for the acquisitions in our sample with negative total gains. We show that the incidence of competition is associated with higher total gains, as well as higher gains to targets.

Financial Constraints Risk

Abstract: We construct an index of firms' external finance constraints via GMM estimation of an investment Euler equation. Unlike the commonly used KZ index, ours is consistent with firm characteristics associated with external finance constraints. Constrained firms' returns move together, suggesting the existence of a financial constraints factor. This factor earns a positive but insignificant average return. Much of the variation in this factor cannot be explained by the Fama-French and momentum factors. Cross-sectional regressions of returns on our index and other firm characteristics show that constrained firms earn higher returns and that the financial-constraints effect dominates the size effect.

Finding the missing honey bee genes: Lessons learned from a genome upgrade

Abstract: The first generation of genome sequence assemblies and annotations have had a significant impact upon our understanding of the biology of the sequenced species, the phylogenetic relationships among species, the study of populations within and across species, and have informed the biology of humans. As only a few Metazoan genomes are approaching finished quality (human, mouse, fly and worm), there is room for improvement of most genome assemblies. The honey bee (Apis mellifera) genome, published in 2006, was noted for its bimodal GC content distribution that affected the quality of the assembly in some regions and for fewer genes in the initial gene set (OGSv1.0) compared to what would be expected based on other sequenced insect genomes. Here, we report an improved honey bee genome assembly (Amel_4.5) with a new gene annotation set (OGSv3.2), and show that the honey bee genome contains a number of genes similar to that of other insect genomes, contrary to what was suggested in OGSv1.0. The new genome assembly is more contiguous and complete and the new gene set includes ~5000 more protein-coding genes, 50% more than previously reported. About 1/6 of the additional genes were due to improvements to the assembly, and the remaining were inferred based on new RNAseq and protein data. Lessons learned from this genome upgrade have important implications for future genome sequencing projects. Furthermore, the improvements significantly enhance genomic resources for the honey bee, a key model for social behavior and essential to global ecology through pollination.

Cognitive biases and heuristics in medical decision making: a critical review using a systematic search strategy.

Abstract: Background. The role of cognitive biases and heuristics in medical decision making is of growing interest. The purpose of this study was to determine whether studies on cognitive biases and heurist...