Purpose -The purpose of this paper is to propose a conceptual model to investigate the determinants of information retweeting in microblogging based on Heuristic-Systematic Model. Design/methodology/approach -Microblogging data about emergency events from Sina microblogging (http://weibo.com) are collected and analyzed with text mining technology. The proposed hypotheses are tested with logistic and multiple linear regressions. Findings -The results show that source trustworthiness, source expertise, source attractiveness, and the number of multimedia have significant effects on the information retweeting. In addition, source expertise moderates the effects of user trustworthiness and content objectivity on the information retweeting in microblogging. Practical implications -This study provides an in-depth understanding of what makes information about emergency events in microblogging diffuse so rapidly. Based on these findings the emergency management organizations in China can apply the microblogging to spread useful information, and these findings also provide practical implications for microblogging system designers. Originality/value -The primary value of this paper lies in providing a better understanding of information retweeting in microblogging based on Heuristic-Systematic Model. Organizations that would like to adopt the microblogging platform in emergency situations to improve the ability of emergency response can benefit from the findings of this study.

In this paper, we study the possibility of building two-field models of dark energy with equation of state across -1. Specifically we will consider two classes of models: one consists of two scalar fields (Quintessence + Phantom) and another includes one scalar (Phantom) and one spinor field (Neutrino). Our studies indicate to some extent that two-field models give rise to a simple realization of the dynamical dark energy model with the equation of state across w = −1.

Observing dark energy dynamics is the most important aspect of the current dark energy research. In this paper we perform a global analysis of the constraints on the property of dark energy from the current astronomical observations. We pay particular attention to the effects of dark energy perturbations. Using the data from SNIa (157 "gold" sample), WMAP and SDSS we find that the best fitting dark energy model is given by the dynamical model with the equation of state across -1. Nevertheless the standard ΛCDM models are still a very good fit to the current data and evidence for dynamics is currently not very strong. We also consider the constraints with the recent released SNIa data from SNLS.

In this paper we study the duality in two-field Quintom models of Dark Energy. We find that an expanding universe dominated by Quintom-A field is dual to a contracting universe with Quintom-B field.