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61.
Investigation of modern biometric data indicates that it may be possible to distinguish wildcats from house cats in many instances. Applying the log‐ratio (log‐difference) technique to archaeological samples from medieval northern Europe, and to mixed samples of wildcats and house cats, shows that the differentiation may not always be clear, and the possibility that some samples include hybrids is discussed. The technique is applied to samples from the Orkney Islands to demonstrate that single wildcat specimens can be identified in small samples. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
62.
本文以2000-2017年人文地理学的SSCI论文为基础数据,通过文献计量法分析了国际人文地理学的发展格局、地区差异和多样性。结果显示:①国际人文地理学存在着高度极化的发展格局,其中英美占据绝对的优势,欧洲国家构成了第二圈层,中国是唯一进入世界人文地理大国的发展中国家。②根据不同国家的学科结构,全球人文地理学大国大致可以分成四大阵营——盎格鲁国家、亚太国家、中南欧国家和北欧国家,这些国家的学科分异表现出了很强的地域性和历史传承性。③最后,本文发现人文地理学学科的多样性与单位研发投入的SSCI论文之间存在着较为显著的正相关关系,即学科结构越均衡越有利于学科的创新和高水平论文的产出。  相似文献   
63.
Defining the extent of human activity around settlement sites is of particular significance in archaeology as it may define peripheral activity areas and thus the site's boundary. In Near Eastern archaeology, site boundaries are usually defined by the presence of architectural and other macroscopic archaeological remains. Here we use the phytolith concentrations and morphotype assemblages, as well as changes in the mineralogical composition of the sediments in and around the small Iron Age site of Izbet Sartah in central Israel to determine the site boundaries. The site has a shallow stratigraphy and highly bioturbated sediments. Coincidental changes in the clay/quartz ratio and phytolith concentrations define the boundary between high and low impact anthropogenic activities. This boundary is generally some 20 m away from the architectural remains. In addition, we note that the phytoliths in the site's core show clear evidence of having been affected by chemical dissolution (i.e., diagenesis), while those in the vicinity of the site's boundary have undergone severe diagenesis. These observations indicate that phytolith diagenesis will affect site boundaries determination, as well as phytolith-based reconstructions of activity areas. We propose that phytolith preservation depends on the initial amount of available silica, the depth of burial with respect to the active root area of modern vegetation, and the presence of fresh phytoliths in the soil.  相似文献   
64.
The goal of this paper is to develop a modified Bouc-Wen hysteretic model from cyclic loading test data for reinforced columns, including the behavior of stiffness degradation, strength deterioration, pinching and softening effects of RC members. Seismic demands on this inelastic single degree of freedom system when subjected to both near-fault ground motion and far-field ground motion excitations were examined.

The cyclic loading test of reinforced concrete columns was experimentally observed and a system identification computer program was developed to solve each control parameter of the hysteretic model. A least-squared method for identifying parameters of the model is proposed in this paper. The hysteretic constitutive law produces a smoothly varying hysteresis such as the control-parameters for strength deterioration, stiffness degradation, pinching and softening effects. Two implementations of (1) flexure damage and (2) shear damage were conducted to provide better understanding of hysteretic behavior of RC structural members. A pseudo-dynamic experiment was also developed to verify the model parameters.

Based on the developed hysteretic model, the seismic demand of this inelastic model was investigated by using both near-fault ground motion data and far-field ground motion data as input motion. An RT inelastic response spectrum from different hysteretic models was generated.  相似文献   
65.
The role of residual deformations when evaluating the performance of multi-storey frame structures subjected to ground motion is investigated in this paper. The limitations of damage indices available in the literature, either based on ductility, energy dissipation or a combination of both, in capturing such a significant aspect of the seismic response of frame structures are discussed. The concept of residual deformations as a critical complementary indicator to cumulative damage, introduced in a companion paper (Part I) for single-degree-of-freedom (SDOF) systems, is herein extended to multi-degree-of-freedom (MDOF) frame systems. The seismic performance of multi-storey frame structures, either representative of new designed or existing structures, is investigated, focusing on the response in terms of residual deformations. Residual deformations are shown to be sensitive to the hysteretic rule adopted, to the system inelastic mechanism as well as to the seismic intensity. The influence of higher modes and P-Δ effects on the final residual deformations is addressed. A combination of maximum drift and residual drift in the format of a performance matrix is used to define the system's global performance levels and is then extended to a framework for an alternative performance-based seismic design and assessment approach.  相似文献   
66.
基于2009-2012年全国31个省、自治区、直辖市的旅游安全网络关注度的百度指数,采用泰尔指数测算方法,分析全国旅游安全网络关注度的区域差异特征,研究发现:1旅游安全网络关注度总体呈现出平稳增长态势,但相比我国互联网上网人数还较小;2区域间、区域内和以省际为单元的旅游安全网络关注度差异显著;3区域间旅游安全网络关注度差异是造成以省际为单元的旅游安全网络关注度差异的主要原因,区域内旅游安全网络关注度对以省际为单元的旅游安全网络关注度的贡献率很小;4西部地区的旅游安全网络关注度省际规模位序低于中部、东部地区,东部地区旅游安全网络关注度指数一直靠前;5整体上,2011-2012年全国和三大区域的旅游安全治理信息的网络关注度较高,所占比重最大;中部地区对旅游安全治理信息的网络关注度明显高于东部和西部地区;2011年和2012年东、中、西部三大区域假日旅游安全信息网络关注度所占比例较接近。  相似文献   
67.
旅游景气指数研究回顾与展望   总被引:2,自引:0,他引:2  
景气指数是识别和预测经济波动、经济周期的重要指标。目前国内已有学者开始研究旅游景气指数,取得了初步成果,但也存在着在指标选取和周期选择方面的不足之处;也正是因为存在这种缺失,笔者希望通过此文为旅游景气指数研究提供一种新的思路。  相似文献   
68.
创新投入在城市群内的空间格局是城市群内城市间创新功能分工的综合体现,对城市群整体创新绩效有着较为深刻的影响。基于此,本文以长江经济带6 大城市群为样本,借用城市基尼系数和城市首位度方法,计算了其创新投入的空间格局和演化趋势,并运用面板协整的方法分析了城市群整体创新绩效与创新投入空间格局之间的均衡及因果关系。研究发现:①6 大城市群中长三角城市群、武汉城市群和长株潭城市群的创新资源配置属于单核结构模式,其余的城市群为"双中心"或"多中心"模式;②城市群整体技术创新绩效与创新投入空间格局的城市首位度之间存在"倒U型"关系;③城市群技术创新绩效与城市首位度之间互为长期因果关系,但是从短期看,仅存在城市首位度对技术创新绩效的单向因果关系。  相似文献   
69.
When a Canada‐wide daily climate time series, covering the period 1950–2010, became available, an opportunity arose to analyze the time series for trends of a variety of temperature indices. The 6,833 climate grid cells covering Alberta, each with an area of 10 km by 10 km, allowed the detailed mapping of 30 temperature indices across the province. From each time series, an annual series was computed, which then enabled trend analyses using the non‐parametric Mann‐Kendall and Sen Slope tests. New maps could be created at an unprecedented spatial resolution, and an associated website was developed to access all trends and changes between 1950 and 2010 for all grid cells at albertaclimaterecords.com . The confidence levels of some temperature trends exceed 99%, while others are below 80%. In Alberta's south, annual average temperatures have increased by 1°C to 2°C since the 1950s, but in Alberta's north the increase is 2°C to 4°C. The growing season has lengthened by between one and five weeks since the 1950s, while the number of frost days has declined. The most significant trends observed were increases in mean annual and winter temperatures, and declines in the number of days below ?20°C and heating degree days.  相似文献   
70.
Economic utility indices provide a means of interpreting butchery and transport decisions reflected in the relative abundance of skeletal elements. Because of destructive taphonomic processes, interpreting skeletal element abundances in terms of carcass transport strategies requires that faunal analysts consider only those elements which accurately reflect their original abundances following human discard. In this study we use resampling techniques to examine the impact of sample size on correlations between high-survival skeletal element frequencies and economic utility in four simulated population assemblages reflecting distinct carcass transport strategies. Correlations alone do not accurately reflect the true relationship between bone abundance and economic utility as particular transport strategies have a tendency to generate high frequencies of Type II errors as sample size decreases. We show that the Shannon evenness index can be used as a quantitative means of distinguishing between bone assemblages characterized by subtle variations in skeletal element abundances. The evenness index can also be used to evaluate whether observed correlations reflect sampling error. Results from our simulations are applied to three published faunal assemblages to evaluate likely carcass transport strategies.  相似文献   
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