Evaluation of Goodness-of-fit Tests for the Cox Proportional Hazards Model with Time-Varying Covariates

The proportional hazards (PH) model, proposed by Cox (1972), is one of the most popular survival models for analyzing time-to-event data. To use the PH model properly, one must examine whether the data satisfy the PH assumption. An alternative model should be suggested if the PH assumption is invalid. The main purpose of this thesis is to examine the performance of five existing methods for assessing the PH assumption. Through extensive simulations, the powers of five different existing methods are compared; these methods include the likelihood ratio test, the Schoenfeld residuals test, the scaled Schoenfeld residuals test, Lin et al. (2006) score test, and the martingale-based residuals test. Results from SAS and R show that the power will vary depending on the form of hazard. For the hazard considered here with a clear jump point at which the PH assumption is violated, the power depends on the time to the violation of proportional hazards, the direction and magnitude of the hazard’s change, and the censoring rate of the data. Leukemia remission and Stanford heart transplant data were used to illustrate testing of the five methods

Offensive Advertisements Influence You More Than Me: An Examination of the Third-Person Effects in the Chinese Cultural Context

This study examined the third-person effect (TPE) hypothesis (Davison, 1983) in offensive advertising in the Chinese cultural context. Based on a survey of 1,539 Chinese Internet users about the third- and firstperson effects among offensive ads, neutral ads, and public service ads, the study inquires into the relationship between the TPE and respondents’ levels of acceptance toward advertising. Besides confirming the TPE existence in an Eastern cultural context, the results suggest that the TPE predict wordof-mouth (WOM) spreading for both offensive and neutral product ads, but not for PSAs. Theoretical contributions and managerial implications of these findings are discussed

Closeness or Distance? An Investigation of Employee–Organization Relationships: From a Psychological Distance Perspective

It is of great significance to grasp and control the relationship between organizations and employees for the healthy development of an organization. This paper measured the closeness and distance of the employee–organization relationship. The results were based on an investigation of 554 employees. (1) The mean value of the employee–organization psychological distance (EOPD) was 3.51, indicating that the relationship between the employee and organization was not optimistic. (2) 48.79% of the 554 interviewees maintained “existence” relationships with their organizations, 28.13% of people maintained “exclude” relationships with their organizations, 20.44% had a “loyalty” relationship, while only 2.64% had an “integrated” relationship with their organization. (3) EOPD showed significant differences in terms of age, marital status, education, career, position and area of residence. (4) Detailed analysis was undertaken to explore the distribution characteristics of four relationships, and specific rules were found. Our research provided a new perspective and related references for the further study of organizational management

Feasibility of Oil Slick Detection Using BeiDou-R Coastal Simulation

Oil spills, which can cause severe immediate and long-term harm to marine ecological environments for decades after the initial accident, require rapid and accurate monitoring. Currently, optical and radar satellite images are used to monitor oil spills; however, remote sensing generally needs a long revisit period. Global Navigation Satellite System reflected signals (GNSS-R) can provide all-weather and all-day ocean monitoring and is therefore more suitable for oil spill monitoring. To assess the feasibility of the BeiDou Navigation Satellite System reflected signals (BeiDou-R) in detecting oil slicks, a BeiDou-R coastal simulated experiment is performed in this study on the oil slick distribution of an oil pipeline explosion accident. We set up an observation point and selected observation satellites, and a delay-Doppler map (DDM) of an oil-slicked sea surface under coastal scenarios was created by combining the mean-square slope (MSS) model for oil-slicked/clean surfaces and the Zavorotny–Voronovich (Z–V) scattering model. DDM simulation of the coastal scenarios effectively represents the scattering coefficient distribution of the presence of an oil slick. Theoretical analysis revealed that oil slicks can be detected within a radius of less than 5 km around the specular reflection point (SP) for BeiDou-R coastal simulation

Controllable thioester-based hydrogen sulfide slow-releasing donors as cardioprotective agents

Hydrogen sulfide (H2S) is an important signaling molecule with promising protective effects in many physiological and pathological processes. However, the study of H2S has been impeded by the lack of appropriate H2S donors that could mimic its slow-releasing process in vivo. Herein, we report the rational design, synthesis, and biological evaluation of a series of thioester-based H2S donors. These cysteine-activated H2S donors release H2S in a slow and controllable manner. Most of the donors comprising an allyl moiety showed significant cytoprotective effects in H9c2 cellular models of oxidative damage. The most potent donor 5e decreased the mitochondrial membrane potential (MMP) loss and lactate dehydrogenase (LDH) release in H2O2-stimulated H9c2 cells. More importantly, donor 5e exhibited a potent cardioprotective effect in an in vivo myocardial infarction (MI) mouse model by reducing myocardial infarct size and cardiomyocyte apoptosis. Taken together, our studies demonstrated that these new allyl thioesters are potential cardioprotective agents by releasing H2S