This research communication aims to characterize the prevalence, molecular characterization and antimicrobial resistance profiling of Streptococcus agalactiae isolated from clinical mastitis in China. A total of 140 Strep. agalactiae isolates were identified from 12 out of 201 farms in 6 provinces, overall herd prevalence was 18.6% and the MLST analysis showed clonal complexes (CC) 103 and CC 67 were present in these herds with CC 103 predominant, accounting for 97.9%. Isolates were mostly sensitive to the tested antimicrobials: penicillin, ceftiofur, amoxi/clav, cefquinome, and vancomycin (100%), followed by cefalexin (97.9%), oxacillin (96.4%), enrofloxacin (95.7%), erythromycin (89.3%), and clindamycin (88.6%). Only 19.3 and 0.7% of isolates were sensitive to tetracycline and daptomycin, respectively, and sequence type (ST) 103 was most resistant to antimicrobials. In conclusion, CC 103 was the predominant subgroup of bovine mastitis Strep. agalactiae in China, and most antimicrobials apart from tetracycline and daptomycin were effective.

Haemorrhagic fever with renal syndrome (HFRS), a rodent-borne disease, is a major public health concern in both developed and developing countries. China is the most severe endemic country in the world, constituting 90% of the cases. Although the incidence of HFRS has substantively decreased in most areas of China, HFRS has rebounded remarkably in some epidemic areas. Xuancheng is one of these areas. In this study, we collected the case data reported recently in Xuancheng and designed a 1:3 case−control study. The Chi-square test, univariate and multivariate logistic regression analysis were performed. In all cases, farmers made up the highest proportion of occupations. And there were 20 variables with statistical significance including indoor hygienic conditions; the surrounding environment; whether bitten by rats at work and other criteria. In addition, exposure to rodents and rats bites is a high-risk factor for HFRS. Rodent density was calculated at 20.9% (159/760), the virus carrier rate was 9.4% (15/159) and the index of rats with a virus was about 2.0%. Exposure to rodents and insect bites is also high-risk factors for HFRS among local residents in Xuancheng. More importantly, during the flood years, the increased density of rodents led to an increased risk of human exposure to rodents. As our statistical analysis proves, targeted strategies should be developed and implemented to reduce the incidence of local diseases in the future.

Social media play an important role in emergency management. The location of citizens and distance from a disaster influence the social media usage patterns. Using the Tianjin Port Explosion, we apply the correlation analysis and regression analysis to explore the relationship between online engagement and location. Citizens’ online engagement is estimated by social media. Three dimensions of the psychological distance – spatial, temporal, and social distances – are applied to measure the effects of location and distance. Online engagement is negatively correlated to such 3 kinds of the distance, which indicates that citizens may pay less attention to a disaster that happens at a far away location and at an area of less interaction or at a relatively long period of time. Furthermore, a linear model is proposed to measure the psychological distance. The quantification relationship between online engagement and psychological distance is discussed. The result enhances our understanding of social media usage patterns related to location and distance. The study gives a new insight on situation awareness, decision-making during disasters.

Nano-sized TiN-reinforced Ti metal matrix composites were fabricated by powder metallurgical route, which includes high-energy ball milling pretreatment and subsequent hot-press sintering treatment. The phase composition and microstructure of the sintered samples were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Results showed that N2 was absorbed and solubilized into TiH2 by milling pretreatment, and TiN was formed during sintering process and was fine to a grain size of 20–100 nm. The final phase composition of the composites was αTi, βTi, and TiN with solution N in matrix. Mechanical tests showed that with increasing milling time, the hardness of the composites increased by 31, 58, 93, and 101% compared with pure Ti. The compressive strength initially increased and later decreased to 2440 and 2120 MPa when milled for 1.5 and 2 h, respectively.

In this work the quantitative and qualitative ability of a kinetic-theory-based two-fluid model (KT-TFM) is assessed in a state of fully periodic sedimentation (fluidization), with a focus on statistically steady, unstable (clustered) states. The accuracy of KT-TFM predictions is evaluated via direct comparison to direct numerical simulation (DNS) data. The KT-TFM and DNS results span a rather wide parameter space: mean-flow Reynolds numbers on the order of 1 and 10, mean solid volume fractions from 0.1 to 0.4, solid-to-fluid density ratios from 10 to 1000 and elastic and moderately inelastic (restitution coefficient of 0.9) conditions. Data from both KT-TFM and DNS display a rich variety of statistically steady yet unstable structures (clusters). Instantaneous snapshots of KT-TFM and DNS demonstrate remarkable qualitative agreement. This qualitative agreement is quantified by calculating the critical density ratio at which the structure transitions from a chaotic, dynamic state to a regular, plug-flow state, with good overall comparisons. Further quantitative assessments of mean and fluctuating velocities show good agreement at high density ratios but weaker agreement at intermediate to low density ratios depending on the mean-flow Reynolds numbers and solid fractions. Deviations of the KT-TFM results from the DNS data were traced to a breakdown in one of the underlying assumptions of the kinetic theory derivation: high thermal Stokes number. Surprisingly, however, even though the low Knudsen number assumption, also associated with the kinetic theory derivation, is violated throughout most of the parameter space, it does not seem to affect the good quantitative accuracy of KT-TFM simulations.

Nanoporous carbon membranes (NCMs) were fabricated by the blends of resorcinol–formaldehyde (RF) resin and Pluronic F-127 through the processes of assembly, membrane-casting, solidification, and pyrolysis. The effect of the catalyst type (i.e., NaOH and Na2CO3) on the structure and property of precursors and their derived NCMs was investigated. The as-obtained precursors and NCMs were characterized by thermogravimetry, differential scanning calorimetry, x-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, elemental analysis, nitrogen adsorption, and gas permeation techniques. The results have shown that defect-free NCMs can be easily procured by the NaOH and Na2CO3 catalysts. In contrast, the precursor made from the Na2CO3 catalyst exhibits higher char yield than that from NaOH after pyrolysis. NaOH-based NCMs are beneficial for the separation of H2/N2 and CO2/N2 gas pairs. Na2CO3-based NCMs are more favorable for the separation of O2/N2 with an ideal selectivity of 6.29 and an O2 permeability of 3.27 Barrer.

Close binary black holes (BBH) are important not only in astrophysics but they would be the strongest gravitational wave sources in the universe. Galaxy-galaxy merging systems are mostly found in optical and X-ray images. In radio, however, the VLBI can resolve the close binary system at pc scale, if their nuclei are radio loud. Recently we analyzed the archive VLBI data of PKS 1155+251, it shows twin core-jets like VLBI structure. In this poster, we present preliminary result from analyzing of the archive data. Further investigations with high frequency VLBI observations are required to confirm if it is a true BBH system.

Fast high precision relative Global Navigation Satellite System (GNSS) positioning is very important to various applications and ambiguity resolution is a key requirement. It has been a continuing challenge to determine and fix GNSS carrier-phase ambiguity, especially for medium- and long-distance baselines. In past research, with dual-frequency band Global Positioning System (GPS), it is almost impossible for fast ambiguity resolution of medium- and long-distance baselines mainly due to the ionospheric and tropospheric effects. With the launch of the BeiDou system, triple-frequency band GNSS observations are available for the first time. This research aims to test the ambiguity resolution performance with BeiDou triple-frequency band observations. In this research, two mathematical models are compared: zenith tropospheric delay as an unknown parameter versus corrected tropospheric delay. The ambiguity resolution performance is investigated in detail with BeiDou observations. Different distance baselines are tested: 45 km, 70 km and 100 km and the performances are investigated with different elevation cut-off angles. Also the performance with BeiDou alone and combined BeiDou and GPS are compared. Experimental results clearly show that with practical observations of triple-frequency bands, ambiguity of medium- or long-distance baselines can be fixed. The results also show that: the performance of ambiguity resolution with an elevation cutoff angle of 20° is much better than that of 15°; The performance with tropospheric effect corrected is slightly better than that with tropospheric effect as an estimated parameter; Dual-frequency band GPS observations will benefit ambiguity resolution of integrated BeiDou and GPS.

The structures of the defect perovskite Pb1−3/2xLaxTiO3 prepared by the solid-state method were investigated in the solubility range of 0.05 ⩽ x ⩽ 0.30 with 0.05 increment by x-ray Rietveld method. In the system Pb1−3/2xLaxTiO3, the atom displacements of Ti (δTi) and Pb/La (δPb/La) along the spontaneous polarization (Ps) direction (c axis) decrease nonlinearly with increasing La content, while the value of δTi/δPb/La decreases linearly. The shape of oxygen octahedron of compounds Pb1−3/2xLaxTiO3 is independent of the La content. The calculated value of Ps decreases linearly in the solubility range of 0.05 ⩽ x ⩽ 0.30. In the refinement process, the hkl dependence of diffraction line broadening was also taken into account. The anisotropy of microstrain-like broadening observed in Pb1−3/2xLaxTiO3 might be ascribed to occurrence of compositional inhomogeneity between the crystallites.