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.

Mean racial‐ethnic differences in employee sales performance: the moderating role of diversity climate

Abstract: Using data from a sample of 6,130 workers employed in 743 stores of a large, U.S. retail organization, this study assessed whether diversity climate moderated mean racial-ethnic differences in employee sales performance. Findings indicated Whites exhibited significantly higher sales performance than Hispanics but not Blacks, as moderated by diversity climate. As hypothesized, racial-ethnic disparities disfavoring Blacks and Hispanics were largest in stores with less supportive diversity climates and smallest in stores with highly pro-diversity climates. Financial analysis of these interactions revealed sizable increments in sales per hour in response to effective diversity management, with strong organizational bottom-line implications. Limitations of the study and future research needs are noted. The United States workforce is becoming more demographically diverse in terms of race-ethnicity, sex, and age (Doverspike, Taylor, Shultz, & McKay, 2000; Fullerton & Toossii, 2001). Due to increasing numbers of personnel from underrepresented groups entering firms, diversity management will become more paramount. Numerous benefits of diversity have been offered including coverage of projected labor shortages, increased access to untapped consumer markets, improved corporate image, reduced legal liability, and greater creativity, problem-solving ability, employee performance, and market share (Cox, 1994; Joshi, Liao, & Jackson, 2006; Richard, Barnett, Dwyer, & Chadwick, 2004; Sacco & Schmitt, 2005). Mean racial-ethnic group differences in job performance, disfavoring Blacks and Hispanics, relative to Whites, challenge the purported

Incorporation of Titanium into Mesoporous Silica Molecular Sieve SBA-15

Abstract: Mesoporous silica molecular sieve SBA-15 has been synthesized and incorporated with variable amounts of titanium via incipient-wetness impregnation with titanium isopropoxide in ethanol followed by calcination. Characterization by powder X-ray diffraction, nitrogen adsorption, X-ray photoelectron, Raman, and diffuse reflectance ultraviolet spectroscopies has been carried out to understand the chemical nature of the titanium. The results suggest that titanium is present in two distinct chemical forms and that their relative amounts depend on the titanium loading. At low titanium loading of 1 atom % relative to silicon, the titanium ions are monatomically dispersed and the pore size of SBA-15 is not altered. This isolated titanium species reaches a maximum concentration around 6 atom % relative to silicon. At higher titanium loading, titanium dioxide (anatase) is also formed. The materials with significant titanium dioxide formation have reduced pore diameters, which suggests that the titanium dioxide exist...

Evaluating Value-at-Risk Models with Desk-Level Data

Abstract: We present new evidence on disaggregated profit and loss and VaR forecasts obtained from a large international commercial bank. Our dataset includes daily P/L generated by four separate business lines within the bank. All four business lines are involved in securities trading and each is observed daily for a period of at least two years. Given this rich dataset, we provide an integrated, unifying framework for assessing the accuracy of VaR forecasts. A thorough Monte Carlo comparison of the various methods is conducted to provide guidance as to which of these many tests have the best finite-sample size and power properties. The Caviar test of Engle and Manganelli (2004) performs best overall but duration-based tests also perform well in many cases.

Circadian rhythms in olfactory responses of Drosophila melanogaster

Abstract: The core mechanism of circadian timekeeping in arthropods and vertebrates consists of feedback loops involving several clock genes, including period (per) and timeless (tim)1,2. In the fruitfly Drosophila, circadian oscillations in per expression occur in chemosensory cells of the antennae, even when the antennae are excised and maintained in isolated organ culture3. Here we demonstrate a robust circadian rhythm in Drosophila in electrophysiological responses to two classes of olfactory stimuli. These rhythms are observed in wild-type flies during light–dark cycles and in constant darkness, but are abolished in per or tim null-mutant flies (per01 and tim01) which lack rhythms in adult emergence and locomotor behaviour. Olfactory rhythms are also abolished in the per 7.2:2 transgenic line in which per expression is restricted to the lateral neurons of the optic lobe4. Because per 7.2:2 flies do not express per in peripheral oscillators, our results provide evidence that peripheral circadian oscillators are necessary for circadian rhythms in olfactory responses. As olfaction is essential for food acquisition, social interactions and predator avoidance in many animals, circadian regulation of olfactory systems could have profound effects on the behaviour of organisms that rely on this sensory modality.

Managerial Agency and Bond Covenants

Abstract: Based on an analysis of the agency risk for bondholders from managerial entrenchment and fraud, we derive and test refutable hypotheses about the influence of managerial agency risk on bond covenants, using a comprehensive database of corporate bonds from the 1993--2007 period. Managerial entrenchment and the risk of managerial fraud significantly influence the use of covenants, in the direction predicted by the agency-theoretic framework. Our analysis highlights the varied effects of entrenchment on different types of agency risks faced by bondholders: Entrenched managers aggravate investment risk, but ameliorate risk from shareholder opportunism. Covenant use also responds efficiently to the quality of information available regarding the risk of managerial fraud. The Author 2009. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org, Oxford University Press.