The emergence of the H7N9 influenza virus in humans in Eastern China has raised concerns that a new influenza pandemic could occur. Here, we used a ferret model to evaluate the infectivity and transmissibility of A/Shanghai/2/2013 (SH2), a human H7N9 virus isolate. This virus replicated in the upper and lower respiratory tracts of the ferrets and was shed at high titers for 6 to 7 days, with ferrets showing relatively mild clinical signs. SH2 was efficiently transmitted between ferrets via direct contact, but less efficiently by airborne exposure. Pigs were productively infected by SH2 and shed virus for 6 days but were unable to transmit the virus to naïve pigs or ferrets. Under appropriate conditions, human-to-human transmission of the H7N9 virus may be possible.

Abstract. In this paper, double commutativity and the reverse order law for the core inverse are considered. en, new characterizations of the Moore-Penrose inverse of a regular element are given by one-sided invertibilities in a ring. Furthermore, the characterizations and representations of the core and dual core inverses of a regular element are considered.

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：In this study, the impact behavior of ten types of high performance self-compacting concrete (HPSCC) was explored using the drop-weight method. The HPSCC specimens were reinforced with steel rebars and different fibers for comparison with plain concrete. The reinforcement mechanism of the influences of steel rebars and different fibers on failure impact energy was explained. The composite effects of hybrid use of steel rebars with different fibers on the failure impact energy were also compared. The penetration depth for each mixture was analyzed. Test results showed that the macro fibers could greatly improve the failure impact energy both in plain and reinforcement concrete. Moreover, the toughness, penetration depth, stress redistribution could be improved obviously due to the positive hybrid effect of rebars and macro fibers in reinforced concrete. The statistical analysis technique was introduced to evaluate the experimental data, and the goodness of fit tests showed that the distribution of the blow numbers to the first crack and up to the final failure followed the two-parameter Weibull distribution.