Focusing on the exchange relationship norm when the business ends,this paper explore the firm's decision in response to the environmental uncertainty under the conditions of 'information dispersing of transaction results among firms' and 'ending the transaction dependence',the authors collect 312 surveys from 3 provinces and use MANOVA and GLM to test the proposed hypotheses.The empirical results show that exchange network characters influence the independence and information transmission hence makes significantly effect on firm's exit strategy.It results indicate that the influence of environmental uncertainty on solidarity norm is negatively mediated by the exchange network density and the influence of environmental uncertainty on the information-sharing norm as well as the flexibility norm are negatively mediated by higher exchange network centrality when business ends.
Spread velocity, epidemic threshold, and infection density at steady state are three non-negligible features describing the spread of epidemics. Combining these three features together, a new network robustness metric with respect to epidemics was proposed in this paper. The real-time robustness of the network was defined and analyzed. By using the susceptible–infected (SI) and susceptible–infected–susceptible (SIS) epidemic models, the robustness of different networks was analyzed based on the proposed network robustness metric. The simulation results showed that homogeneous networks present stronger robustness than do heterogeneous networks at the early stage of the epidemic, and the robustness of the heterogeneous networks becomes stronger than that of the homogeneous ones with the progress of the epidemic. Moreover, the irregularity of the degree distribution decreases the network robustness in homogeneous networks. The network becomes more vulnerable as the average degree grows in both homogeneous and heterogeneous networks.
Research progress on 2,4-D inducing morphogenesis effect and several possible mechanism were summarized.As there were some limitations in the application of 2,4-D in tissue culture,the regulating mechanism in morphogenesis was advised to be studied deeply.
Photosynthesis,chlorophyll fluorescence parameters and physiological indexes were analyzed on the eight open-pollinated half-sib Elaeagnus angustifolia families of 2-year old seedlings to explore their election and utilization potential difference for providing theoretical basis of genetic improvement.Study results showed that photosynthetic capacity and the physiological state of half-sib Elaeagnus angustifolia families were found different,and different indexes reflected the differently among families.Net photosynthetic rate(Pn),transpiration rate(Tr),intercellular CO2 concentration(Ci),photochemical quenching coefficient(qP),optical system II actual photochemical efficiency(Yield),chlorophyll,and praline content of eight Elaeagnus angustifolia families were significantly different,while the differences of stomatal conductance(Gs),photochemical efficiency of PSⅡ(Fv/Fm),soluble sugar,malondialdehyde and betaine were not significant.The most sensitive index was proline,followed by qP and Yield,whike Fv/Fm,soluble sugar and Ci were not sensitive.Family's photosynthetic capacity and physiological status was comprehensive evaluated by using membership function analysis method to deal with significant difference indexes and the conclusion was family 1 family 7 family 5 family 2 family 8 family 4 family 3 family 6.Single indexes and comprehensive indexes of family 1 were excellent performance and it had the strongest photosynthetic capacity,the best physiological status and the largest election of utilization potential.
The floristic statistics and preliminary analyses of the wild campanulaceae in Hebei Province showed that in Hebei there are 20 species and 2 varieties of campanulaceae.These plants belong to 6 genera.Among all these plants,14 species and 2 varieties belong to Adenophora,and 6 species of Adenophora are unique in China.The similarity coefficient of the Campanulaceae genera and species between Hebei and the neighboring provinces is relatively high.The similarity coefficient of genera to Beijing and Inner Mongolia is the highest,90.91%,but the lowest to Tianjin,66.67%.The similarity coefficient of species has the highest percentage,73.17%,to Shanxi,and the lowest percentage,48.28%,to Tianjin.Campanulaceae are found throughout Hehei province.But a few are unevenly distributed and are unique in this area.
AbstrcatIn the 1990s, with the development of economy,thruway program has become one important aspect of Shaanxi's infrastructure construction,which to some extent increase the contradiction between sustainable development and resource and environment.Therefore it is important for scientific researcher to make economic benefit and environment benefit and social benefit harmoniously and to achieve their continuable and healthy development.Taking Mianxian— Ningqiang thruway as a case,the natural characteristic along the road is analyzed and the influence of road construction on environment is discussed,moreover some corresponding countermeasures about prevention and cure are put forward according to the real situation.
In terms of the recognition of road sign,a method of feature extraction based on K-L discrete transformation is introduced,which proved an effective method for road-sign recognition.
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