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61.
The interaction of geomorphic and ecologic landscape components has been largely conceptualized as independent. In one direction, geomorphic processes and landforms shape the distribution of biota. Conversely, in the other direction, biota modify geomorphic processes and landforms. Increasingly, the interactions between geomorphic and ecological components are more circular and developmentally intertwined. In this paper, I integrate these two independent perspectives within the framework of complexity theory. I outline four themes that characterize complex systems in biogeomorphology: multiple causality and the concept of recursivity, the influence of organisms that function as ecosystem engineers, the expression of an ecological topology, and ecological memory. Implicit in all of these themes is the recognition that biogeomorphic systems are open and path dependent. They may exhibit a range of assembly states, from self-reinforcing stability domains to more transient configurations of organisms and environment.  相似文献   
62.
By applying the 'theory of synchronization' from the science of complexity to studying the regional regularity of ore formation within the Nanling region of southern China,a characteristic target-pattern regional ore zonality has been discovered.During the early and late Yanshanian epoch(corresponding respectively to the Jurassic and Cretaceous periods),two centers of ore formation emerged successively in the Nanling region;the former is mainly for rare metals(W,Sn.Mo.Bi,Nb) and one rare-earth element(La...  相似文献   
63.
地震时空丛集的多重分形研究   总被引:19,自引:1,他引:19       下载免费PDF全文
为探索大地震发生的可预测性,应用分形理论并根据标准数盒子的数值计算方法,研究了华北地区历史地震和唐山地区地震活动的空间分布特征,估算了地震活动能量的分维值并研究了其多重分形谱的几何结构.初步结果显示出大地震发生前,广义维值有明显的下降过程,分形谱f(α)结构有右偏现象.在低于上述时空层次的唐山地区,孕震系统也有类似特征出现.这些异常现象揭示出孕震动力系统的物理机理和激变前的某些不稳定性.  相似文献   
64.
Fisheries are complex human-in-nature systems. The conventional approach to fisheries systems has been to treat them as predictable and controllable. As complex systems they are neither of the two and have to be approached differently. Complex systems often exhibit the capacity to self-organize or adapt, even without outside influence. If this is true of fisheries, it should lead to a radically different approach to management of fisheries systems that places much emphasis on enabling self-organization, learning and adaptation. Conceptual and practical frameworks for enabling activities are needed.  相似文献   
65.
This article analyzes changing forms of transnational security governance and security expertise in Guatemala. It is argued that the dynamics of transnational security governance in Guatemala are directly related to the local appropriation of knowledge promoted by external security experts. As an expertise-based form of “intervention by invitation,” local political and economic elites engage in securitization strategies in order to invite external experts to intervene. In turn, through their intervention these experts provide resources that are “captured” and exploited by local actors to pursue their own interests. As a consequence, transnational security governance fails as it deviates from the original plans and programs experts try to implement. The analysis of these processes sheds light on how and why failure in the context of transnational security governance is productive. Failure, we argue, triggers a self-reinforcing interventionary feedback loop that aims at “fixing” the shortcomings of previous interventions by mobilizing new forms of external security expertise. In tracing the dynamics of this interventionary feedback loop over time, this article contributes to understanding of the role of experts and policy failure in the (re)making of transnational security governance.  相似文献   
66.
By applying the ‘theory of synchronization’ from the science of complexity to studying the regional regularity of ore formation within the Nanling region of southern China, a characteristic targetpattern regional ore zonality has been discovered. During the early and late Yanshanian epoch (corresponding respectively to the Jurassic and Cretaceous periods), two centers of ore formation emerged successively in the Nanling region; the former is mainly for rare metals (W, Sn,Mo, Bi, Nb) and one rare-earth element (La) and was generated in the Jurassic period; whereas the latter is mainly for base metals (Cu, Pb, Zn, Sb, Hg), noble metals (Au, Ag), and one radioactive element (U) and was generated in the Cretaceous period. Centers of ore formation were brought about by interface dynamics respectively at the Qitianling and Jiuyishan districts in southernHunan province. The characteristic giant nonlinear target-pattern regional ore zonality was generated by spatio-temporal synchronization process of the Nanling complex metallogenic system. It induced the collective dynamics and cooperative behavior of the system and displayed the configuration of the regional ore zonality. Then dynamical clustering transformed the configuration into rudimentary ordered coherent structures. Phase dynamics eventually defined the spatio-temporal structures of the target-pattern regional ore zonality and determined their localization and distribution. A new methodology for revealing regional ore zonality is developed, which will encourage further investigation of the formation of deep-seated ore resources and the onset of large-scale mineralization.  相似文献   
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