To gain further insight into the molecular epidemiology of Hantaan virus (HTNV) in Guizhou, China, rodents were captured in this region in 2004 and 2005. In addition, serum samples were collected from four patients. Ten hantaviruses were isolated successfully in cell culture from four humans, two Apodemus agrarius, three Rattus norvegicus and one Rattus nitidus. The nucleotide sequences for their small (S), medium (M) and partial large (L) segments were determined. Phylogenetic analysis of the S and M segment sequences revealed that all of these isolates belong to the species HTNV, suggesting a spillover of HTNV from A. agrarius to Rattus rats. All available isolates from Guizhou were divided into four distinct groups either in the S segment tree or in the M segment tree. The clustering pattern of these isolates in the S segment tree was not in agreement with that in the M or L segment tree, showing that genetic reassortment between HTNV had occurred naturally. Analysis of the S segment sequences from available HTNV strains indicated that they formed three clades. The first clade, which comprised only viruses from Guizhou, was the outgroup of clades II and III. The viruses in the second clade were found in Guizhou and mainly in the far-east Asian region, including China. However, the viruses in the third clade were found in most areas of China, including Guizhou, in which haemorrhagic fever with renal syndrome (HFRS) is endemic. Our results reveal that the highest genetic diversity of HTNV is in a limited geographical region of Guizhou, and suggest that Guizhou might be a radiation centre of the present form of HTNV. INTRODUCTIONHaemorrhagic fever with renal syndrome (HFRS) is an important human disease; 60 000 to 100 000 cases requiring hospitalization are reported annually worldwide, with the majority occurring in China (Johnson, 1999;Zhang et al., 2004). The disease is caused by hantaviruses, members of the genus Hantavirus in the family Bunyaviridae (Nichol et al., 2005). The virus genome consists of three separate segments of negative-stranded RNA referred to as small (S), medium (M), and large (L) segments, which encode nucleocapsid protein (NP), two envelope glycoproteins (Gn and Gc) and viral RNA-dependent RNA polymerase (RdRP), respectively (Plyusnin et al., 1996). In contrast to other genera of the Bunyaviridae, hantaviruses are not transmitted by arthropods (Schmaljohn & Hjelle, 1997). They establish a chronic infection that causes no apparent harm to rodents of the Muridae family, which are their natural hosts (Childs et al., 1989; Hutchinson et al., 2000;Kurata et al., 1983;Li et al., 1995;Netski et al., 1999). Currently, at least 22 distinct hantavirus species have been identified worldwide; all of these hantaviruses except Thottapalayam virus (TPMV) are carried by rodents (Nichol et al., 2005). Each rodent-borne hantavirus species appears to be associated primarily with one (or a few closely related) rodent species (Nichol et al., 2005; Plyusnin GenBank accession numbers of the S, M and L segment...

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Coal and gas outburst is one of the major serious natural disasters during underground coal, and the shock air flow produced by outburst has a huge threat on the mine safety. In order to study the two-phase flow of a mixture of pulverized coal and gas of a mixture of pulverized coal and gas migration properties and its shock effect during the process of coal and gas outburst, the coal samples of the outburst coal seam in Yuyang Coal Mine, Chongqing, China were selected as the experimental subjects. By using the self-developed coal and gas outburst simulation test device, we simulated the law of two-phase flow of a mixture of pulverized coal and gas in the roadway network where outburst happened. The results showed that the air in the roadway around the outburst port is disturbed by the shock wave, where the pressure and temperature are abruptly changed. For the initial gas pressure of 0.35 MPa, the air pressure in different locations of the roadway fluctuated and eventually remain stable, and the overpressure of the outburst shock wave was about 20~35 kPa. The overpressure in the main roadway and the distance from the outburst port showed a decreasing trend. The highest value of temperature in the roadway increased by 0.25 • C and the highest value of gas concentration reached 38.12% during the experiment. With the action of shock air flow, the pulverized coal transportation in the roadway could be roughly divided into three stages, which are the accelerated movement stage, decelerated movement stage and the particle settling stage respectively. Total of 180.7 kg pulverized coal of outburst in this experiment were erupted, and most of them were accumulated in the main roadway. Through the analysis of the law of outburst shock wave propagation, a shock wave propagation model considering gas desorption efficiency was established. The relationships of shock wave overpressure and outburst intensity, gas desorption rate, initial gas pressure, cross section and distance of the roadway were obtained, which can provide a reference for the protection of coal and gas outburst and control of catastrophic ventilation.Keywords: coal and gas outburst; laboratory simulation experiment; two-phase flow of a mixture of pulverized coal and gas; shock wave; propagation model

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This study explores factors that influence problem-solving coping style across cultures. There was no significant difference in applying problem solving across U.S., Taiwanese, and Chinese samples. The effective predictors of problem solving in the U.S. and Chinese samples were self-efficacy and trait resilience, respectively. in the Taiwanese sample, predictors were selfefficacy and trait resilience. Trait resilience was found to mediate the effect of self-efficacy on problem solving in the Taiwanese and Chinese samples. Practical implications are discussed.

Hydraulic fracturing is an effective technology for enhancing the extraction of reservoir methane, as proved by field experience and laboratory experiments. However, unlike conventional reservoirs, coal seams had high stress sensitivity and high anisotropy. Therefore, the efficiency of hydraulic fracturing in coal seams needs to be investigated. In this study, hydraulic fracturing was performed at Nantong mine in the southeast Sichuan basin, China. The field investigation indicated that the hydraulic fracturing could significantly enhance the methane extraction rate of boreholes ten times higher than that of normal boreholes in one of the minable coal seams (named #5 coal seam). The performance of hydraulic fracturing in three districts revealed that compared with south flank, the fluid pressure was higher and the injection rate was lower in north flank. The methane extraction rate of south flank was inferior to that of north flank. It indicated hydraulic fracturing had less effect on #5 coal seam in south flank. Moreover, the injection of high-pressure water in coal seams could also drive methane away from boreholes. The methane extraction rate of the test boreholes demonstrated the existence of methane enrichment circles after hydraulic fracturing. It indicated that hydraulic fracturing did act on #5 coal seam in south flank. However, due to the high stress sensitivity of coal seams and the high geo-stress of south flank, the induced artificial fractures in #5 coal seam might close with the decline of the fluid pressure that led to a sharp decline of the methane extraction rate.

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