Modeling the morphology of gully cross sections in the Yuanmou Dry-hot Valley

Abstract

Characterizing gully cross sections (GCs) is essential for calculating the volume and erosion rate of the gully. However, little research has focused on modeling the morphology of GCs. This study investigated 456 GCs with a laser distance meter located at the mouth, middle, and head of 152 gullies in the Yuanmou Dry-hot Valley of China; mapped them with AutoCAD software; fitted them with 2nd–6th degree polynomial functions, and discussed the correlation between the coefficients and the morphology of GCs. The results showed that: (1) using a 2nd-degree polynomial function (y = ax² + bx + c) to describe the morphology of GCs produced a better result than other polynomial functions; (2) the coefficient a of 2nd-degree polynomial function was correlated with depth (r = ?0.226, p < 0.01), gradient (r = 0.545, p < 0.01), and activities; and (3) the symmetry axis (?b/2a) of 2nd-degree polynomial function increased with gully change from left-deflection to right-skewed, and the absolute value showed the asymmetrical degree (r = 0.216, p < 0.01). This study will not only help to understand the morphology and evolution of gullies, but will also provide a scientific basis for prevention of gully erosion.     

Experimental research on the effect of slope morphology on bank collapse in mountain reservoir

Farmers along the Amazon River each year face multiple natural hazards that threaten crop production and limit the potential for agricultural development of the expansive floodplain and active channel. In this paper we report the findings of a study of natural hazard-related risk associated with rice production on silt bars in the active channel of the Amazon River near Iquitos, Peru. Data were gathered in four rice producing communities in 2014 using household surveys (n = 83 households), focus group discussions, surveying of land elevations along the Amazon River, and interpretation of remote sensing imagery. The probability, extent, and severity of rice crop shortfalls were estimated for recent production years and the economic losses to farming households were also assessed. Our findings point to a very high risk of crop shortfalls due to natural hazards, suggesting that a good year brings rice farmers bounty and a bad year, near penury. River stage reversals (repiquetes) and edaphic conditions were found to be more problematic than the often cited hazard of high and/or early floods. Also surprisingly, farmers’ perceptions of hazards and risk diverged markedly from actual shortfalls experienced during the production years studied. Our results provide the first quantitative estimates of risk due to the multiple natural hazards along the Amazon River and point to the need to assist lowland farmers with risk mitigation so as to unlock the considerable potential of Amazon floodlands for agricultural production.     

新冠疫情期间武汉樱花的情感效应

运用大数据文本挖掘和分析工具,对比新冠疫情期间武汉和非武汉地区居民所发布的微文,探究了武汉樱花在不同居民群体间情感效应的作用机制,研究发现：1）本地居民樱花微文的关注点多而分散,非本地居民的关注点少而集中;2）武汉樱花对不同地区居民情感的影响与疫情发展状况紧密相关;3）武汉樱花在疫情期间对武汉居民具有情感支持效应,对非武汉地区居民具有情感凝聚效应;4）疫情改变人的情感和景观解读背景,并赋予景观新的意义,新的景观意义反作用于居民,构成情感闭合回路。最后提出建议,抗疫恢复工作应多关注居民心理层面的缺失,从居民与城市、景观的情感关系入手,向武汉居民传达城市美好生活理念。     

基于土壤地球化学数据的资源与环境评价信息系统设计与实现

基于应用土壤地球化学数据进行环境评价和资源预测的需求,本文独立开发了基于土壤地球化学数据的资源与环境评价信息系统。系统融合了反距离加权插值模型以及具有稳健变异函数的地统计学克里格插值模型,并在此基础上引人了非线性的多维分形插值模型;同时,系统结合资源与环境预测和评价的实际需求,集成了单因子指数、地累积指数、环境地球化学...     

Status of Satellite Orbit Determination and Time Synchronization Technology for Global Navigation Satellite Systems

In the form of satellite ephemerides and clock parameters, the space datum and system time information of one global navigation satellite system (GNSS) is transferred to users. With the continuous updating in the satellite payload such as the high-precision atomic clock, the monitoring and tracking technique such as the inter-satellite link, and in the data processing technique, the accuracy and real-time performance of the satellite ephemeris and clock error products are steadily improved. Starting from December 27th, 2018, the BeiDou Navigation System 3, or BDS-3, has provided the accurate and reliable basic positioning, navigation, and timing (PNT) service for the users in the countries within the “one belt and one road”. This paper has summarized the faced challenges of the precise orbit determination and time synchronization from the regional BDS-2 system to the BDS-3 global system, and the specific solutions at the control segment. In addition, this paper has compared the BDS with other GNSS systems in terms of technical characteristics. Finally, aiming at a higher accuracy and more reliable PNT service, the road map of precise orbit determination and time synchronization technique for the next generation navigation systems is discussed, which will provide a reference for developing the global navigation satellite systems with an even higher accuracy.     

马超营断裂带区域地球化学特征

该文探讨了马超营断裂带内各地层的成矿元素丰度特征,阐述了该带内成矿元素的分布特征及分布规律,总结了Ａｕ及有关元素Ａｇ、Ｐｂ、Ｚｎ、Ｍｏ、Ｃｏ、Ｎｉ、Ｍｎ、Ｂａ、Ｓｒ、Ａｓ、Ｓｂ、Ｂｉ等异常的特征及其分布规律。研究成果表明：马超营断裂带的韧性—韧脆性剪切带是本区Ａｕ及与其相关的Ａｇ、Ｐｂ、Ｚｎ等成矿元素异常规模、形态和空间分布的控制因素。     

云南东北部拱王山末次冰期

1 Introduction The Gongwang mountains constitute one of the few high m ountains of irrefutable late Pleistocene glaciation in eastern China. This area is one of the m ost extensively studied Quaternary geologicallocationsin eastern China and the interpret…     

关于确保甘肃省祁连山生态保护红线落地并严守的科技支撑建议

祁连山是中国西部重要生态安全屏障,是国家重点生态功能区,其生态保护与治理一直受到国家、地方政府和当地居民高度关注。目前,在祁连山的生态保护工作中,缺乏对现状基础数据的全面掌握,区域经济发展与生态环境保护矛盾突出,生态环境综合监测系统不完备,生态补偿机制推进实施缺乏创新。在全面梳理祁连山目前存在的重大生态问题的基础上,提出了祁连山生态保护红线落地并严守的建议,包括加快开展祁连山综合科学考察、完善并落实开展生态补偿机制、探索以正面清单为导向的协调发展模式、促进生态安全与地方经济社会可持续发展相协调、进一步实施重大配套政策、完善保障支撑体系等。     

我国省区间工业结构的异同与结构转换的调控途径

通过计算分析,本文认为我国省区之间工业部门结构既有趋同性,又存在趋异性;趋同性是基本合理的,而趋异性预示着各省区产业结构进一步调整的方向。我国省区工业结构差异主要发现在综合专业化能力、部门深层结构、结构质量三方面。以此为依据,本文提出了我国省区工业结构转换的调控途径。     

Initiation of primary cell culture from amphioxus <Emphasis Type="Italic">Branchiostoma belcheri tsingtauense</Emphasis>

Amphioxus, a cephalochordate, is an important model fish for studies in evolution and comparative biology. A successful cell culture from amphioxus tissues in vitro would help understanding some basic issues. To determine the optimal culture conditions for proliferation of amphioxus cells, primary cultures were initiated from buccal cirri, tail, gill, gut and metapleural fold of amphioxus Branchiostoma belcheri tsingtauense. The media tested were L-15, F-12, M 199, MEM, DMEM, PRMI 1640 and LDF, each was supplemented with 20% fetal bovine serum. The optimal conditions include tail tissue cultured in L-15 or F-12 with supplement of 20% FBS and 1.5% NaCl at about 25°C. Supported by Doctoral Initial Fund of Ludong University (No.43304)