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71.
Humans and livestock have always dwelling together, especially in rural areas. Based on a multi-method approach of ethnographic fieldwork, grounded theory and one-way multivariate analysis of variance, this paper explores human and livestock dwelling. The findings show that human and livestock dwelling form a special type of human dwelling place, with forms defined as co-, mix- and dis-dwelling. Then, from co-, mix- to dis-dwelling constructed a story line to the evolution of human and livestock dwelling forms, which further explains the entire dwelling situation of humans and livestock, including the dimensions of human dweller, livestock dweller, the rural environment and special events. Among co-, mix- and dis-dwelling significant differences existed between human and livestock individuals, the nature of rural environment, vernacularity and rural tourism development. Between co- and dis-dwelling, significant differences existed in seventeen aspects; between mix- and dis-dwelling, significant differences existed in eleven aspects; meanwhile, no significant differences existed between co- and mix-dwelling. Accordingly, this suggested that human and livestock dwelling forms can be divided into mix- and dis-dwelling. This study on humans and livestock dwelling relationship offer a new perspective on rural and animal geography. This paper is an exploratory foray into rural dwelling geography as part of the Anthrozoology study and broadens the scope of extant scholarship on human dwelling morphology, as well as analyses the spatial relationships between human and livestock dwelling. 相似文献
72.
Huan WU Xiaomeng LI Guy J.-P.SCHUMANN Lorenzo ALFIERI Yun CHEN Hui XU Zhifang WU Hong LU Yamin HU Qiang ZHU Zhijun HUANG Weitian CHEN Ying HU 《大气科学进展》2021,38(1):1-7
The prolonged mei-yu/baiu system with anomalous precipitation in the year 2020 has swollen many rivers and lakes,caused flash flooding,urban flooding and landslides,and consistently wreaked havoc across large swathes of China,particularly in the Yangtze River basin.Significant precipitation and flooding anomalies have already been seen in magnitude and extension so far this year,which have been exerting much higher pressure on emergency responses in flood control and mitigation than in other years,even though a rainy season with multiple ongoing serious flood events in different provinces is not that uncommon in China.Instead of delving into the causes of the uniqueness of this year’s extreme precipitation-flooding situation,which certainly warrants in-depth exploration,in this article we provide a short view toward a more general hydrometeorological solution to this annual nationwide problem.A“glocal”(global to local)hydrometeorological solution for floods(GHS-F)is considered to be critical for better preparedness,mitigation,and management of different types of significant precipitation-caused flooding,which happen extensively almost every year in many countries such as China,India and the United States.Such a GHS-F model is necessary from both scientific and operational perspectives,with the strength in providing spatially consistent flood definitions and spatially distributed flood risk classification considering the heterogeneity in vulnerability and resilience across the entire domain.Priorities in the development of such a GHS-F are suggested,emphasizing the user’s requirements and needs according to practical experiences with various flood response agencies. 相似文献
73.
This paper derives the force of the electromagnetic radiation on left-handed materials (LHMs) by a direct application of the Lorentz law of classical electrodynamics. The expressions of radiation force are given for TE-polarised and TM-polarised fields. The numerical results demonstrate that electromagnetic waves exert an inverse lateral radiation force on each edge of the beams, that is, the lateral pressure is expansive for TE-polarised beams and compressive for TM-polarised beams. The investigation of the radiation force will provide insights into the fundamental properties of LHMs and will provide to better understanding of the interaction of light with LHMs. 相似文献
74.
利用正交试验设计,研究了温度、盐度和酸碱度3种环境因素逆境下对三疣梭子蟹(Portunus trituberculatus)幼蟹的致死效应,以阐明三疣梭子蟹幼蟹对不同逆境环境的抵抗力大小。3种逆境环境因素的水平分别是:温度为10,15,30,35℃;盐度为10,15,35,40;酸碱度为6.0,6.5,9.0,9.5。结果表明,盐度变化对梭子蟹幼蟹的影响最大,其次为酸碱度,再次为温度。对于温度而言,低温下幼蟹的存活时间较长;对于盐度而言,高盐度逆境比低盐度逆境下的存活时间长;对于pH值而言,碱性环境下的存活时间比酸性环境下的存活时间长。 相似文献
75.
三疣梭子蟹(Portunus trituberculatus)作为重要的海洋经济动物,其常见体色(头胸甲)为茶绿色。近年来在我国沿海海域海捕三疣梭子蟹中开始出现体色为紫色的一类梭子蟹,除体色不同外,二者表型特征并无显著差异。对两种体色三疣梭子蟹不同个体的线粒体COI和16S rRNA基因进行了序列比对分析以判定二者之间的亲缘关系。结果发现COI和16S rRNA基因在两种体色三疣梭子蟹群体中的核苷酸序列一致性分别为99.87%和99.88%,表明紫色三疣梭子蟹并未发生亚种的分化,即紫色和茶绿色群体属于同一个种。并利用GenBank数据库检索了梭子蟹科其他15种海产蟹的16S rRNA序列,进行了序列同源性比对分析和分子系统学方面的探讨,为梭子蟹种属分类学研究提供分子依据。 相似文献
76.
三疣梭子蟹作为重要的海洋经济动物,其常见体色为茶绿色。近年来在我国东部沿海海域海捕三疣梭子蟹中开始出现体色为紫色的一类梭子蟹,除体色不同外,二者表型特征并无显著差异。为确定两种体色三疣梭子蟹之间的关系,本文对两种体色三疣梭子蟹不同个体的线粒体COl和16srRNA基因进行了比较分析以判定体色的差异是否由于种属的差异引起的。通过对以上两个基因部分序列的SSCP和相关序列测定分析,发现在紫色和茶绿色群体中这两个线粒体保守序列基因的SSCP电泳条带图谱相似,序列分析表明COl和16srRNA基因在两种体色三疣梭子蟹群体中的核苷酸序列相似度分别为99.81%和99.91%。以上结果表明,紫色三疣梭子蟹并未发生亚种的分化,即紫色和茶绿色群体属于同一个种。此外,紫色梭子蟹群体的线粒体DNA序列在进化关系上较茶绿色群体更为保守。 相似文献
77.
78.
京津冀地区植被时空动态及定量归因 总被引:2,自引:0,他引:2
作为气候变化的敏感指示器,植被的物候、生长、空间分布格局等特征及其动态变化主要取决于气候环境中的水热条件,因此在气候变化背景下,气候-植被关系成为了全球变化研究的前沿和热点问题。本文综合平均温度、降水、水汽压、湿度、日照时数、SPEI等气候因子,坡度、坡向海拔等地形因子及人为活动因子,应用地理探测器方法针对2006-2015年京津冀地区不同季节NDVI、不同地貌类型区、不同植被类型区生长季NDVI的定量归因研究,揭示了过去10年间植被时空分布格局,及植被对气候、非气候因素响应的季节差异与区域差异,以期为生态工程的建设与修复提供参考意义。趋势分析表明:①2006-2015年京津冀地区NDVI呈现增加趋势,但存在显著的空间差异,如山地生长季NDVI的增长速率大于平原、台地、丘陵等地;②基于地理探测器的定量归因结果表明,降水是年尺度上NDVI空间分布的主导因子(解释力39.4%),土地利用与降水的交互作用对NDVI的影响最为明显(q=58.2%);③NDVI对气候因子的响应存在季节性及区域性差异,水汽压是春季NDVI空间分布的主导因子,湿度是夏、秋两季的主导因子,土地利用是冬季的主导因子;④影响因子对生长季NDVI的解释力因不同地貌类型区、不同植被类型区而差异显著。 相似文献
79.
Black carbon and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of China’s marginal seas 总被引:8,自引:0,他引:8
This study investigates the distribution of black carbon (BC) and its correlation with total polycyclic aromatic hydrocarbons (ΣPAH) in the surface sediments of China’s marginal seas. BC content ranges from <0.10 to 2.45 mg/g dw (grams dry weight) in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents (average 2.18 mg/g dw), which comprises a significant fraction (27%–41%) of the total organic carbon (TOC) preserved in the sediments. In ... 相似文献
80.
随着频率使用率的提高, 射电天文台址地面或空间存在强电磁干扰致使望远镜接收机系统处于非线性状态. 为减少强电磁干扰的影响、提高天文观测效率, 提出了一种基于望远镜远场区域的强干扰源规避方法. 首先, 通过仿真分析确定的射电望远镜远场方向图, 结合望远镜与干扰源之间的位置关系, 分析了强电磁干扰到达射电望远镜焦点处的功率响应, 并依据接收机第2阶中频放大器性能参数, 确定射电望远镜处于非饱和状态的规避角度计算方法. 其次, 采用该方法计算分析了民航飞机对射电望远镜的影响, 若民航飞机上有主动发射的干扰源, 且不经过反射等传播现象, 当射电望远镜主波束轴偏开一定方向后, 可有效降低对射电望远镜的干扰强度. 相似文献