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951.
Cognition and symbolic thinking are viewed as important features of modern human behavior.Engraved objects are seen as a hallmark of cognition and symbolism,and even as evidence for language.Accumulated evidences including engraved bones,ochre,ostrich eggshells and stone artifacts were unearthed from Africa,Europe,Levant even Siberia Paleolithic sites.But the archaeological evidence for this,including beads,ornaments,burials,performed objects and engraved objects,is rarely discovered in the Pleistocene of East Asia.The present paper reports an engraved stone object unearthed in the Early Late Paleolithic levels about 30 ka BP at the Shuidonggou site(SDG) in northwestern China.It was unearthed in the 1980’s excavation from Lower culture unit of SDG1 but was identified in 2011 when the first author of this article observed the collection from the 1980’s excavations stored in the Institute of Archaeology of Ningxia Hui Autonomous Region for further detailed lithic analysis.This lithic artifact is the first engraved non-organic object of the Paleolithic period found in China.In order to clarify the details of the incisions and to document the human intentional modifications,we used a KEYENCE VHX-600 Digital Microscope to measure and observe all the incisions in 3-dimensional perspective.Comparing the natural cracks and analyzing many details of the incisions,we argue that incisions on this stone artifact are the result of intentional behaviors by ancient humans.Also,we exclude the possible other causes including animal-induced damages,post-depositional phenomenon and unintentional by-products.Combining all these features,we suggest that the incisions were made by an intentional behavior and were probably of a non-utilitarian character.Because the nature of most other engraved objects in China is debate,we cannot get a clear scenario of the emergence and progress of modern human behavior in North China.But we infer the possible existence of a counting or recording system,or other symbolic behaviors,which reflect considerably evolved cognitive capacities or modern human behavior in the Early Late Paleolithic of East Asia.  相似文献   
952.
Phosphonylation and aging processes between butyrylcholinesterase with mipafox have been studied at the B3LYP/6-311G(d,p) level of theory. The calculated results indicate that the phosphonylation process employs a two-step addition-elimination mechanism with the addition (the first step) as the rate-limiting step. Two different calculation models revealed that the catalytic triad of butyrylcholinesterase plays an important role in accelerating the reaction. This is the same mechanism as the phosphonylation reaction of acetylcholinesterase by sarin reported by Wang et al. However, the energy barrier of the rate-limiting step in the present reaction is higher than that in phosphonylation reaction of acetylcholinesterase by sarin. This indicates the differences in the phosphonylation activity of sarin and mipafox. The aging process occurs through a two-step addition-elimination mechanism similar to the phosphonylation process with the addition as the rate-limiting step. The solvent effects have been evaluated by using a CPCM model and the results show that the stationary structures and the negative charges around some important atoms involved in the two processes are not significantly different. However, the energy barrier of the phosphonylation process is remarkably decreased, revealing that this process is feasible in solution.  相似文献   
953.
The last glacial period was vital for the distribution and evolution of early modern humans in Asia. The Shuidonggou Late Paleolithic site, dated at 30-20 ka BP, accumulated cultural remains during the important late stage of MIS 3 period in the last glacial. These remains represent characteristics of typical Late Paleolithic conditions in North China:high degree of standardization and morphological variability of tool types, exploitation of bone materials, systematic use of body decorations, extensive use of earth-pit hearths, distinct functional spatial organization within habitations, and conversion of subsistence patterns. These characteristics illustrate early modern human behaviors during the late MIS3 period, and provide clues and perspectives for the analysis of early modern human origins in China. At the same time, the conversion of subsistence patterns is considered to be a combination of multiple early modern human behaviors, as well as the result of the Broad Spectrum Revolution. In this paper, we argue for the dynamic mechanism of Broad Spectrum Revolution from a human behavioral and ecological perspective.  相似文献   
954.
In the research field of proton exchange membrane fuel cells, the design of electrocatalytic activities on Pt-oxide promoter in the anode side has attracted attention for improvement of CO tolerance of Pt in anode side and a lowering of large over-potential loss of the oxygen reduction reaction on the cathode in the fuel cells. In the Pt-oxide promoter series, Pt–CeOx/C is one of the unique systems. It is because the unique behavior of CeOx such as electrochemical redox reaction between Ce3t and Ce4t in the anodic and cathodic reactions of fuel cell is observed. The present short review gives an overview of the recent works for improvement of the CO tolerance of Pt in the Pt–CeOx/C anodes and enhancement of the oxygen reduction reaction activity on Pt in the Pt–CeOx/C cathodes for fuel cell application. To show the design paradigm for fabrication of high quality Pt–CeOx/C electrodes, the authors re-introduced parts of our research results to highlight the important role of interface structure of Pt–CeOx based on the ultimate analysis results. The usefulness of the combined approach of microanalysis and the processing route design is presented.  相似文献   
955.
曲面的三个基本形式的系数矩阵之间关系的证明   总被引:1,自引:1,他引:0  
邢家省  王拥军 《河南科学》2012,(10):1407-1410
给出R3中曲面的3个基本形式的系数矩阵之间关系的一个直接证明,并由此得到曲面的3个基本形式之间的关系表示及其一些应用.  相似文献   
956.
工程优化设计中的近似模型技术   总被引:2,自引:0,他引:2  
解决复杂系统的建模优化问题,需根据具体的应用环境,选择合适的近似模型。本文对响应面模型、多元自适应回归样条模型、克立格模型、径向基函数模型、支持向量回归模型等近似模型的性能特点和适用范围进行了系统的比较研究,在分析这些近似模型基本特性的基础上,选取具有广泛代表性的测试函数,并综合考虑问题的复杂度、非线性程度、采样点的规模及分布等多个因素,对上述5种近似模型的全局和局部拟合能力、鲁棒性等进行了较为全面的比较评价,并给出应用实例。  相似文献   
957.
Multi-source information can be utilized collaboratively to improve the performance of information retrieval. To make full use of the document and collection information, this paper introduces a new information retrieval model that relies on the Dempster-Shafer theory of evidence. Each query-document pair is taken as a piece of evidence for the relevance between a document and a query. The evidence is combined using Dempster’s rule of combination, and the belief committed to the relevance is obtained. Retrieved documents are then ranked according to the belief committed to the relevance. Several basic probability assignments are also proposed. Extensive experiments over the Text REtrieval Conference (TREC) test collection ClueWeb09 show that the proposed model provides performance similar to that of the Vector Space Model (VSM). Under certain probability assignments, the proposed model outperforms the VSM by 63% in terms of mean average precision.  相似文献   
958.
Parameter estimation plays a critical role for the application and development of S-shaped growth model in the agricultural sciences and others.In this paper,a modified particle swarm optimization algorithm based on the diffusion phenomenon(DPPSO) was employed to estimate the parameters for this model.Under the sense of least squares,the parameter estimation problem of S-shaped growth model,taking the Gompertz and Logistic models for example,is transformed into a multi-dimensional function optimization problem.The results show that the DPPSO algorithm can effectively estimate the parameters of the S-shaped growth model.  相似文献   
959.
江西红色文化的形成过程,就是中国共产党在不断的探索中逐步走向成熟的历史过程,就是中国革命正确道路的形成过程。今天的我们站在新的历史起点上,重温中国共产党在血雨腥风的战争年代在江西这片红土地上展开的波澜壮阔的革命实践,并不仅仅出于一种历史的兴趣,更重要的是获得一种正确看待和处理当代中国社会现实和发展前景的理论眼光和科学态度。红色文化在当代中国社会文化生活中重新焕发出巨大的生命力并且获得广大人民群众情感上的普遍认同,既是红色文化本身所具有的独特魅力和鲜明特征的体现,也是当代中国社会现实生活所面临的时代处境的内在要求。  相似文献   
960.
利用下降流不变集方法和极小对偶作用原理,证明了一类自治Hamilton系统4个周期解的存在性定理.  相似文献   
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