Two types of sampling plots of seabuckthom （Hippophae rhamnoides） communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure a...Two types of sampling plots of seabuckthom （Hippophae rhamnoides） communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity. Composition and dominant species of each community were analyzed by the importance value of species as an index. The number of individuals and the importance value, as well as Sorensen＇s similarity coefficient, Shannon-Wiener diversity index, Pielou＇s evenness index and Simpson＇s dominance index, were used as indices to compare characteristics of community structure, similarity and biodiversity between plantations and natural forests of seabuckthom. The results indicate that the importance values of species of natural seabuckthom communities were dispersed and the difference between dominant species was not statistically significant. Diversity indices of natural seabuckthom communities reflected by species richness and evenness were higher than that of plantations. Community structure of natural seabuckthom forests is more complex. We propose that natural forest can be used as sample to guide selection of plant species in silviculture in order to improve biodiversity of plantation.展开更多
In quantum chromodynamics （QCD）, the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., t...In quantum chromodynamics （QCD）, the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., the current quark mass. By studying the linear response of the dressed quark propagator to the presence of a nonzero quark mass, we derive a model-independent formula for the scalar susceptibility, which contains the dressed quark propagator G（p） and the dressed scalar vertex F（p, 0）. The numerical values of the scalar susceptibility Xs are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach by employing two typical forms of model gluon propagator.展开更多
We do a numerical calculation on the quark-loop effects on the dressed gluon propagator in the chiral limit. It is found that the quark-loop effects on the dressed gluon propagator are significant in solving the quark...We do a numerical calculation on the quark-loop effects on the dressed gluon propagator in the chiral limit. It is found that the quark-loop effects on the dressed gluon propagator are significant in solving the quark propagator in the rainbow approximation of the Dyson-Schwinger equation. The approach we used here is quite general and can also be used to calculate both the chemical potential and current quark mass dependence of the dressed gluon propagator.展开更多
The vector susceptibility is investigated numerically in the Dyson-Schwinger approach. The results agree with those obtained analytically previously by using a simple gluon propagator.
Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chl...Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chloroesters were obtained readily and smoothly in excellent yields.展开更多
We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator are...We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator aresmall but not negligible.We also study the current quark mass dependence on the bag constant.展开更多
脑小血管病指各种病因影响脑部小动脉、小静脉、微动脉、微静脉和毛细血管所导致的一系列临床、影像、病理综合征。焦虑、抑郁是脑小血管病的严重并发症,是影响脑小血管病患者安全及生活质量的因素之一。目前相关的研究对脑小血管病患...脑小血管病指各种病因影响脑部小动脉、小静脉、微动脉、微静脉和毛细血管所导致的一系列临床、影像、病理综合征。焦虑、抑郁是脑小血管病的严重并发症,是影响脑小血管病患者安全及生活质量的因素之一。目前相关的研究对脑小血管病患者的焦虑、抑郁描述较少,对脑小血管病患者的焦虑、抑郁管理无详细的方案。本研究主要是阐述脑小血管病(cerebral small vessel disease,CSVD)的相关知识、临床表现及CSVD焦虑、抑郁的流行病学发展现状,总结CSVD焦虑、抑郁的治疗及干预现状,阐明我国研究的不足之处及展望,以期提高人们对CSVD焦虑、抑郁的认识,为相关工作人员开展有效的干预提供依据。展开更多
基金supported by the State Key Program of National Natural Science of China (Grant No. 30730075)the Program for Changjiang Scholars and Innovative Research Team in Universities (PCSIRT0607)
文摘Two types of sampling plots of seabuckthom （Hippophae rhamnoides） communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity. Composition and dominant species of each community were analyzed by the importance value of species as an index. The number of individuals and the importance value, as well as Sorensen＇s similarity coefficient, Shannon-Wiener diversity index, Pielou＇s evenness index and Simpson＇s dominance index, were used as indices to compare characteristics of community structure, similarity and biodiversity between plantations and natural forests of seabuckthom. The results indicate that the importance values of species of natural seabuckthom communities were dispersed and the difference between dominant species was not statistically significant. Diversity indices of natural seabuckthom communities reflected by species richness and evenness were higher than that of plantations. Community structure of natural seabuckthom forests is more complex. We propose that natural forest can be used as sample to guide selection of plant species in silviculture in order to improve biodiversity of plantation.
基金The project supported in part by National Natural Science Foundation of China under Grant No.10575050the Research Fund for the Doctoral Program of Higher Education under Grant No.20060284020
文摘In quantum chromodynamics （QCD）, the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., the current quark mass. By studying the linear response of the dressed quark propagator to the presence of a nonzero quark mass, we derive a model-independent formula for the scalar susceptibility, which contains the dressed quark propagator G（p） and the dressed scalar vertex F（p, 0）. The numerical values of the scalar susceptibility Xs are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach by employing two typical forms of model gluon propagator.
基金The project supported in part by National Natural Science Foundation of China under Crant No.10575050the Research Fund for the Doctoral Program of Higher Education under Grant No.20060284020
文摘We do a numerical calculation on the quark-loop effects on the dressed gluon propagator in the chiral limit. It is found that the quark-loop effects on the dressed gluon propagator are significant in solving the quark propagator in the rainbow approximation of the Dyson-Schwinger equation. The approach we used here is quite general and can also be used to calculate both the chemical potential and current quark mass dependence of the dressed gluon propagator.
文摘The vector susceptibility is investigated numerically in the Dyson-Schwinger approach. The results agree with those obtained analytically previously by using a simple gluon propagator.
文摘Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chloroesters were obtained readily and smoothly in excellent yields.
文摘We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator aresmall but not negligible.We also study the current quark mass dependence on the bag constant.
文摘脑小血管病指各种病因影响脑部小动脉、小静脉、微动脉、微静脉和毛细血管所导致的一系列临床、影像、病理综合征。焦虑、抑郁是脑小血管病的严重并发症,是影响脑小血管病患者安全及生活质量的因素之一。目前相关的研究对脑小血管病患者的焦虑、抑郁描述较少,对脑小血管病患者的焦虑、抑郁管理无详细的方案。本研究主要是阐述脑小血管病(cerebral small vessel disease,CSVD)的相关知识、临床表现及CSVD焦虑、抑郁的流行病学发展现状,总结CSVD焦虑、抑郁的治疗及干预现状,阐明我国研究的不足之处及展望,以期提高人们对CSVD焦虑、抑郁的认识,为相关工作人员开展有效的干预提供依据。
