In order to investigate the general tendency of soil microbial community responses to fertilizers, a meta-analysis approach was used to synthesise observations on the effects of inorganic and organic fertilizer additi...In order to investigate the general tendency of soil microbial community responses to fertilizers, a meta-analysis approach was used to synthesise observations on the effects of inorganic and organic fertilizer addition(N: nitrogen;P: phosphorus;NP: nitrogen and phosphorus;PK: phosphorus and potassium;NPK: nitrogen, phosphorus and potassium;OF: organic fertilizer;OF+NPK: organic fertilizer plus NPK) on soil microbial communities. Among the various studies, PK, NPK, OF and OF+NPK addition increased total phospholipid fatty acid(PLFA) by 52.0%, 19.5%, 334.3% and 58.3%, respectively;while NP, OF and OF+NPK addition increased fungi by 5.6%, 21.0% and 8.2%, respectively. NP, NPK and OF addition increased bacteria by 6.4%, 9.8% and 13.3%, respectively;while NP and NPK addition increased actinomycetes by 7.0% and 14.8%, respectively. Addition of ammonium nitrate rather than urea decreased gram-negative bacteria(G–). N addition increased total PLFA、bacteria and actinomycetes in croplands, but decreased fungi and bacteria in forests, and the F/B ratio in grasslands. NPK addition increased total PLFA in forests but not in croplands. The N addition rate was positively correlated with the effects of N addition on gram-positive bacteria(G+) and G–. Therefore, different fertilizers appear to have different effects on the soil microbial community. Organic fertilizers can have a greater positive effect on the soil microbial community than inorganic fertilizers. The effects of fertilizers on the soil microbial community varied with ecosystem types. The effect of N addition on the soil microbial community was related to both the forms of nitrogen that were added and the nitrogen addition rate.展开更多
This study investigated Linzhou County in Tibet, which currently hosts the most serious outbreak of Kashin-Beck disease(KBD) in China. This study uses the geographical detector(GeoDetector) algorithm to measure the in...This study investigated Linzhou County in Tibet, which currently hosts the most serious outbreak of Kashin-Beck disease(KBD) in China. This study uses the geographical detector(GeoDetector) algorithm to measure the influences that several risk factors have on KBD prevalence and validates the spatial analysis results with environmental chemistry. Based on a comprehensive examination of 10 potentially related spatial factors and an environmental chemistry analysis of the soil-water-grain-human biogeochemical cycle in the local KBD and non-KBD villages, four main conclusions are drawn.(1) KBD in Linzhou County is a consequence of multiple interrelated environmental factors, of which the most important controlling factor is the stratum factor.(2) The concentrations of selenium(Se) in all environmental media(soil, water, and food) and human tissue in the KBD villages in Linzhou County are lower than those of the non-KBD villages.(3) The intake of Se and chromium(Cr) by local residents is seriously insufficient, especially the average daily dose by ingestion(ADD) for Se in the KBD village, which is only about 4% of the World Health Organization(WHO) recommended lower limit for adult elemental intake.(4) We speculate that the main cause for the local KBD outbreak is a lack of Se in the stratum. This absence leads to a serious Se deficiency in the local population through ecosystem migration and transformation, which will eventually lead to an endemic biogeochemical Se deficiency.展开更多
Frequency attenuation occurs when seismic waves propagate through the porous reservoirs containing hydrocarbons. Current researches on the seismic frequency attenuation mainly focus on the post-stack domain instead of...Frequency attenuation occurs when seismic waves propagate through the porous reservoirs containing hydrocarbons. Current researches on the seismic frequency attenuation mainly focus on the post-stack domain instead of the prestack domain. Here we propose the frequency attenuation gradient vs. offset （FAGVO） based on the amplitude variation with offset and frequency attenuation integral equations. We derive the FAGVO equation that equals to zero in a full-elastic medium and is negative in a viscoelastic medium. FAGVO is affected by the viscosity of the medium, the coefficients of reflection, the frequency variation, and high-frequency attenuation. FAGVO uses the differences of partially stacked data to decrease the interference caused by subsurface strata affecting the frequency attenuation, highlights the frequency attenuation gradient anomalies in hydrocarbon-bearing reservoir pores, and finally realizes the hydrocarbon fluid identification. The method was verified using a two-dimensional wave equation forward model and was found to be cost effective. Furthermore, the method does not require well information, which can be applied in the stage of seismic exploration, especially, in the exploration of a none-well project.展开更多
The market economic system is an economic system of corporate organizations. China＇s sustained and rapid economic development over the past four decades of reform and opening-up was supported by the emergence of its ...The market economic system is an economic system of corporate organizations. China＇s sustained and rapid economic development over the past four decades of reform and opening-up was supported by the emergence of its business community. During this period, China＇s corporate organizations increased, expanded and developed from strength to strength, serving as a solid micro-level basis for the prosperity of the socialist market economic system. Having achieved significant progress, China＇s corporate ownership restructuring led to the common development of enterprises with various forms of ownership. An institutional factor that undergirded corporate prosperity was China＇s choice of a corporate system characterized by the interplay between market competition and government administration. How China＇s corporate organizational system will evolve in the future is determined by（1） how efficiency varies among firms with different ownership systems, and（2） external institutional pressures facing firms in their rapid internationalization process.展开更多
基金The National Key Research and Development Program of China(2016YFC0502001,2016YFC0502005,2017YFA0604801)The Tibet Natural Science Foundation(XZ2018ZRG-141)+1 种基金The National Natural Science Foundation of China(31600432,41571042)The Tibet Science and Technology Major Projects of the Pratacultural Industry。
文摘In order to investigate the general tendency of soil microbial community responses to fertilizers, a meta-analysis approach was used to synthesise observations on the effects of inorganic and organic fertilizer addition(N: nitrogen;P: phosphorus;NP: nitrogen and phosphorus;PK: phosphorus and potassium;NPK: nitrogen, phosphorus and potassium;OF: organic fertilizer;OF+NPK: organic fertilizer plus NPK) on soil microbial communities. Among the various studies, PK, NPK, OF and OF+NPK addition increased total phospholipid fatty acid(PLFA) by 52.0%, 19.5%, 334.3% and 58.3%, respectively;while NP, OF and OF+NPK addition increased fungi by 5.6%, 21.0% and 8.2%, respectively. NP, NPK and OF addition increased bacteria by 6.4%, 9.8% and 13.3%, respectively;while NP and NPK addition increased actinomycetes by 7.0% and 14.8%, respectively. Addition of ammonium nitrate rather than urea decreased gram-negative bacteria(G–). N addition increased total PLFA、bacteria and actinomycetes in croplands, but decreased fungi and bacteria in forests, and the F/B ratio in grasslands. NPK addition increased total PLFA in forests but not in croplands. The N addition rate was positively correlated with the effects of N addition on gram-positive bacteria(G+) and G–. Therefore, different fertilizers appear to have different effects on the soil microbial community. Organic fertilizers can have a greater positive effect on the soil microbial community than inorganic fertilizers. The effects of fertilizers on the soil microbial community varied with ecosystem types. The effect of N addition on the soil microbial community was related to both the forms of nitrogen that were added and the nitrogen addition rate.
基金The Key Research and Development and Transformation Program of Tibet(XZ201901NB08)The Major Science and Technology Project of Tibet(XZ201901NA03,XZ201801NA02).
文摘This study investigated Linzhou County in Tibet, which currently hosts the most serious outbreak of Kashin-Beck disease(KBD) in China. This study uses the geographical detector(GeoDetector) algorithm to measure the influences that several risk factors have on KBD prevalence and validates the spatial analysis results with environmental chemistry. Based on a comprehensive examination of 10 potentially related spatial factors and an environmental chemistry analysis of the soil-water-grain-human biogeochemical cycle in the local KBD and non-KBD villages, four main conclusions are drawn.(1) KBD in Linzhou County is a consequence of multiple interrelated environmental factors, of which the most important controlling factor is the stratum factor.(2) The concentrations of selenium(Se) in all environmental media(soil, water, and food) and human tissue in the KBD villages in Linzhou County are lower than those of the non-KBD villages.(3) The intake of Se and chromium(Cr) by local residents is seriously insufficient, especially the average daily dose by ingestion(ADD) for Se in the KBD village, which is only about 4% of the World Health Organization(WHO) recommended lower limit for adult elemental intake.(4) We speculate that the main cause for the local KBD outbreak is a lack of Se in the stratum. This absence leads to a serious Se deficiency in the local population through ecosystem migration and transformation, which will eventually lead to an endemic biogeochemical Se deficiency.
基金supported by the Major National Science&Technology Project(No.2016ZX05003-003)the National High Technology Research and Development Program of China(863 Program)(No.2013AA064201)
文摘Frequency attenuation occurs when seismic waves propagate through the porous reservoirs containing hydrocarbons. Current researches on the seismic frequency attenuation mainly focus on the post-stack domain instead of the prestack domain. Here we propose the frequency attenuation gradient vs. offset （FAGVO） based on the amplitude variation with offset and frequency attenuation integral equations. We derive the FAGVO equation that equals to zero in a full-elastic medium and is negative in a viscoelastic medium. FAGVO is affected by the viscosity of the medium, the coefficients of reflection, the frequency variation, and high-frequency attenuation. FAGVO uses the differences of partially stacked data to decrease the interference caused by subsurface strata affecting the frequency attenuation, highlights the frequency attenuation gradient anomalies in hydrocarbon-bearing reservoir pores, and finally realizes the hydrocarbon fluid identification. The method was verified using a two-dimensional wave equation forward model and was found to be cost effective. Furthermore, the method does not require well information, which can be applied in the stage of seismic exploration, especially, in the exploration of a none-well project.
文摘The market economic system is an economic system of corporate organizations. China＇s sustained and rapid economic development over the past four decades of reform and opening-up was supported by the emergence of its business community. During this period, China＇s corporate organizations increased, expanded and developed from strength to strength, serving as a solid micro-level basis for the prosperity of the socialist market economic system. Having achieved significant progress, China＇s corporate ownership restructuring led to the common development of enterprises with various forms of ownership. An institutional factor that undergirded corporate prosperity was China＇s choice of a corporate system characterized by the interplay between market competition and government administration. How China＇s corporate organizational system will evolve in the future is determined by（1） how efficiency varies among firms with different ownership systems, and（2） external institutional pressures facing firms in their rapid internationalization process.
