Enhancement of Optical Nonlinearity Through Anisotropic Microstructures

We investigate the polarization dependence of optical nonlinearity enhancement for a uniaxial anisotropic composite of metal nanocrystals in a dielectric host. Three cases are distinguished depending on whether the polarization is parallel, perpendicular or unpolarized with respect to the axis of anisotropy. For the parallel polarization, the results show that the 3D results are qualitatively similar to the 2D case reported recently. For the perpendicular polarization, the results are markedly different from the parallel counterpart: In contrast to the absorption, the enhancement factor actually increases with the anisotropy. Thus the separation of the absorption and enhancement peaks becomes even more pronounced than the parallel polarization case. These results indicate a strong polarization dependence of the nonlinear optical response.Comment: 12 pages, LaTeX format, 9 figures, preliminary results were Reported in the 2nd Tohwa University International Meeting on Statistical Physics held on November 4-7, 1997, accepted for publication by Optics Communications on 7 November 199

Inference and Specification Testing in Threshold Regression with Endogeneity

We propose three new methods of inference for the threshold point in endogenous threshold regression and two specification tests designed to assess the presence of endogeneity and threshold effects without necessarily relying on instrumentation of the covariates. The first inferential method is a parametric two-stage least squares method and is suitable when instruments are available. The second and third methods are based on smoothing the objective function of the integrated difference kernel estimator in different ways and these methods do not require instrumentation. All three methods are applicable irrespective of endogeneity of the threshold variable. The two specification tests are constructed using a score-type principle. The threshold effect test extends conventional parametric structural change tests to the nonparametric case. A wild bootstrap procedure is suggested to deliver finite sample critical values for both tests. Simulations show good finite sample performance of these procedures and the methods provide flexibility in testing and inference for practitioners working with threshold models

The Effect of Knowledge Sharing on IS Outsourcing Success

IS outsourcing is one of the major issues facing organizations in today’s rapidly changing business environment. It is often presented as an attractive business proposition to improve productivity, reduce costs and increase competitiveness. This study examined the relationship between knowledge sharing and IS outsourcing success based on the social capital theory. It shows the knowledge sharing is critical factor for outsourcing partners to face potential changes and challenges over time to lead to IS outsourcing success. The research findings are depicted as following: Trust and shared vision are significant variables to knowledge sharing. The social interaction benefits in building trust and reaching shared vision. Knowledge sharing has a positive effect on IS outsourcing success and organizational learning capability moderates the relationship between knowledge sharing and IS outsourcing success especially for the lower learning capability company

Understanding the Intention of Giving Information in Virtual Communities

The major activity in a virtual community is information exchange among members. However, even in busy virtual communities, usually only a small fraction of members post information actively. Our interest in this study was seeking a better understanding of the psychological determinants that drive people to give information actively and voluntarily. An empirical study was conducted and 273 responses that have experiences in virtual communities were collected. The research model was mainly evaluated and validated with Structural Equation Modeling (SEM)-LISREL. The results suggest that members’ perceived self-efficacy, perceived soft rewards, trust to other members, social identity, and positive anticipated emotions have positively effects on intention of giving information through the mediation of desire

Linezolid and Rifampicin Combination to Combat cfr-Positive Multidrug-Resistant MRSA in Murine Models of Bacteremia and Skin and Skin Structure Infection.

Linezolid resistance mediated by the cfr gene in MRSA represents a global concern. We investigated relevant phenotype differences between cfr-positive and -negative MRSA that contribute to pathogenesis, and the efficacy of linezolid-based combination therapies in murine models of bacteremia and skin and skin structure infection (SSSI). As a group, cfr-positive MRSA exhibited significantly reduced susceptibilities to the host defense peptides tPMPs, human neutrophil peptide-1 (hNP-1), and cathelicidin LL-37 (P < 0.01). In addition, increased binding to fibronectin (FN) and endothelial cells paralleled robust biofilm formation in cfr-positive vs. -negative MRSA. In vitro phenotypes of cfr-positive MRSA translated into poor outcomes of linezolid monotherapy in vivo in murine bacteremia and SSSI models. Importantly, rifampicin showed synergistic activity as a combinatorial partner with linezolid, and the EC50 of linezolid decreased 6-fold in the presence of rifampicin. Furthermore, this combination therapy displayed efficacy against cfr-positive MRSA at clinically relevant doses. Altogether, these data suggest that the use of linezolid in combination with rifampicin poses a viable therapeutic alternative for bacteremia and SSSI caused by cfr-positive multidrug resistant MRSA

ONLINE AUCTION EFFECTIVENESS: OPTIMAL SELLING STRATEGIES FOR ONLINE AUCTION MARKET

The introduction of internet auction has significantly widened the pool of consumers who participate in auctions and increased the number of companies attempting to sell their products in an auction format. Previous empirical research on auctions has focused almost exclusively on the behavior of professional bidders. In this study, we collect data on a large number of internet auctions to explore the outcome of the auction in a real marketplace. In particular, we focus on the characteristic of seller, auction parameter and the effect of supply and demand, and examine these impacts on auction effectiveness

Tunable photonic Bloch oscillations in electrically modulated photonic crystals

We exploit theoretically the occurrence and tunability of photonic Bloch oscillations (PBOs) in one-dimensional photonic crystals (PCs) containing nonlinear composites. Because of the enhanced third-order nonlinearity (Kerr type nonlinearity) of composites, photons undergo oscillations inside tilted photonic bands, which are achieved by the application of graded external pump electric fields on such PCs, varying along the direction perpendicular to the surface of layers. The tunability of PBOs (including amplitude and period) is readily achieved by changing the field gradient. With an appropriate graded pump AC or DC electric field, terahertz PBOs can appear and cover a terahertz band in electromagnetic spectrum