Tulane University

About: Tulane University is a education organization based out in New Orleans, Louisiana, United States. It is known for research contribution in the topics: Population & Blood pressure. The organization has 24478 authors who have published 47205 publications receiving 1944993 citations. The organization is also known as: University of Louisiana.

Stock Market Liquidity and Firm Value

Abstract: This paper investigates the relation between stock liquidity and firm performance. The study documents that firms with liquid stocks have better performance as measured by the firm market-to-book ratio. This result is robust to the inclusion of industry or firm fixed effects, a control for idiosyncratic risk, a control for endogenous liquidity using two stage least squares, and the use of alternative measures of liquidity. To identify the causal effect of liquidity on firm performance, we study an exogenous shock to liquidity --- the decimalization of stock trading --- and document that the increase in liquidity around decimalization improves firm performance. The causes of liquidity’s beneficial effect are investigated: Liquidity increases the information content of market prices and of performance sensitive managerial compensation. Finally, momentum trading, analyst coverage, investor overreaction, and the effect of liquidity on discount rates or expected returns do not appear to drive the results.

Testing Interaction Effects in LISREL: Examination and Illustration of Available Procedures

Abstract: The concomitant proliferation of causal modeling and hypotheses of multiplicative effects has brought about a tremendous need for procedures that allow the testing of moderated structural equation models (MSEMs). The seminal work of Kenny and Judd and Hayduk has been drawn on by several authors in the past 10 years, thus producing procedures that allow for such tests. Yet, utilization of MSEMs in empirical research has been quite rare. The purposes of this article are twofold. First, the authors discuss general issues with respect to multivariate normality, indicators of latent products, the nature of latent products, and identification problems in MSEM. Second, they review and illustrate techniques that are available for the testing of interaction effects in structural equation models.

Novel stabilization mechanism on polar surfaces: ZnO(0001)-Zn.

Abstract: The ($1\ifmmode\times\else\texttimes\fi{}1$) terminated (0001)-Zn surface of wurtzite ZnO was investigated with scanning tunneling microscopy. The surface is characterized by the presence of nanosized islands with a size-dependent shape and triangular holes with single-height, O-terminated step edges. It is proposed that the resulting overall decrease of the surface Zn concentration stabilizes this polar surface. Ab initio calculations of test geometries predict triangularly shaped reconstructions over a wide range of oxygen and hydrogen chemical potentials. The formation of these reconstructions appears to be electrostatically driven.

Toward an integrated model of work experience.

Abstract: Work experience and related concepts such as tenure and seniority have been and continue to be used extensively in a variety of human resource functions. However, research on experience has proceeded without a clear theoretical orientation, adequate consideration of contextual and individual factors, and appropriate attention to measurement and design. These issues are addressed and a model of the work experience construct is offered. Work experience is described as consisting of qualitative and quantitative components that exist at different levels of specification and which interact and accrue over time. The model provides a nomological net for the experience construct linking it to contextual and individual factors critical for the development of experience and its translation into immediate outcomes of work-based knowledge, skills, attitudes, and motivation, and secondary outcomes such as performance. The model provides a basis for specific research propositions and human resource applications that consider work experience as a multidimensional, multilevel, and temporally dynamic construct.

The Role of Human Movement in the Transmission of Vector-Borne Pathogens

Abstract: Background Human movement is a key behavioral factor in many vector-borne disease systems because it influences exposure to vectors and thus the transmission of pathogens. Human movement transcends spatial and temporal scales with different influences on disease dynamics. Here we develop a conceptual model to evaluate the importance of variation in exposure due to individual human movements for pathogen transmission, focusing on mosquito-borne dengue virus. Methodology and Principal Findings We develop a model showing that the relevance of human movement at a particular scale depends on vector behavior. Focusing on the day-biting Aedes aegypti, we illustrate how vector biting behavior combined with fine-scale movements of individual humans engaged in their regular daily routine can influence transmission. Using a simple example, we estimate a transmission rate (R0) of 1.3 when exposure is assumed to occur only in the home versus 3.75 when exposure at multiple locations—e.g., market, friend's—due to movement is considered. Movement also influences for which sites and individuals risk is greatest. For the example considered, intriguingly, our model predicts little correspondence between vector abundance in a site and estimated R0 for that site when movement is considered. This illustrates the importance of human movement for understanding and predicting the dynamics of a disease like dengue. To encourage investigation of human movement and disease, we review methods currently available to study human movement and, based on our experience studying dengue in Peru, discuss several important questions to address when designing a study. Conclusions/Significance Human movement is a critical, understudied behavioral component underlying the transmission dynamics of many vector-borne pathogens. Understanding movement will facilitate identification of key individuals and sites in the transmission of pathogens such as dengue, which then may provide targets for surveillance, intervention, and improved disease prevention.