基于出行时空数据的分时租赁汽车与网约车出行场景比较研究

分时租赁和网约车同属共享汽车,但规模对比悬殊。找到差异化的出行场景有利于分时租赁在网约车主导的共享汽车市场中谋求立足之地。本文以北京地区某分时租赁公司2017年5月1日—30日的出行订单和2018年4月23日—29日的网约车出行订单为研究对象,结合城市兴趣点数据,利用地理信息层次聚类、关联规则等方法挖掘两共享汽车的典型出行场景,并进行比较分析。研究表明：① 网约车主要服务于“通勤出行”和“市内商务区之间的出行”,2种出行场景分别占网约车订单总量的40.3%和28.7%;② 分时租赁主要服务非通勤出行,其特色出行场景是“往返城市旅游景区的出行”、“城市旅游景区之间的出行”和“外城住宅商务混合区的午夜出行”,分别占分时租赁订单总量的24.4%、6.9%和5.5%。③ 在分时租赁的特色出行场景中,分时租赁与网约车或传统租车等共享出行方式相比费用更低,仅占其费用的25%~35%,具有较大的竞争优势。本研究有关出行场景挖掘的方法和结论可以为北京市分时租赁的推广以及其他共享出行研究提供借鉴和参考。     

川东北地区下三叠统飞仙关组白云岩储层研究

在川东北地区下三叠统飞仙关组沉积相模式研究成果的基础上,详细研究了区内白云岩的岩石类型及储集性。结果表明该区各类白云岩主要孔隙类型为粒间溶孔、粒内溶孔、粒间原孔、晶间孔隙、铸模孔、裂缝性溶洞、裂缝等。结合物性资料表明颗粒砂屑溶孔云岩及鲕粒溶孔云岩为Ⅰ类优质储层、鲕粒云岩及砾屑云岩为Ⅱ类好储层、结晶云岩为Ⅲ类较差储层、泥一细粉晶云岩为非储层。     

论天山古洋盆关闭的地质时限——来自伊宁地块石炭系的新证据

天山古洋盆关闭的地质时限倍受地质界关注,久有泥盆纪晚期或石炭纪初期,石炭纪晚期以及二叠纪期间3种分歧。由残余盆地恢复原型盆地,是造山带古洋盆恢复的基础,钙碱系列火成岩可作为古洋盆恢复的重要证据。伊宁地块石炭纪的残余盆地沉积记录、火山岩建造、侵入岩特征、化石组合及古生物地理区系分布特征、地层接触关系及构造变形特征等新成果证实,以区内阿克沙克组与伊什基里克组间广泛而明显的区域性角度不整合面(鄯善运动)为界,下石炭统钙碱性系列火山岩-沉积地层组合发育复杂的不协调褶曲,尖棱褶皱,强烈的揉皱和区域性韧性断层,产出于南方型热带-亚热带古生物地理区系,为区域性挤压构造体制下的岛弧-弧后盆地建造,是塔里木板块的主要组成部分,而上石炭统碱性系列双峰式火山岩及沉积地层组合则是典型的北方型温带古生物地理区的大陆裂谷火山-沉积建造,构造变形极弱,形成于区域性伸展构造环境,是准噶尔板块与塔里木板块缝合后的陆内建造。基于这些新的资料和分析,天山古洋盆的关闭时限是早石炭世晚期。     

Kinematics of the Scorpius-Centaurus OB association

A fine structure related to the kinematic peculiarities of three components of the Scorpius-Centaurus association (LCC, UCL, and US) has been revealed in the UV-velocity distribution of Gould Belt stars. We have been able to identify the most likely members of these groups by applying the method of analyzing the two-dimensional probability density function of stellar UV velocities that we developed. A kinematic analysis of the identified structural components has shown that, in general, the center-of-mass motion of the LCC, UCL, and US groups follows the motion characteristic of the Gould Belt, notably its expansion. The entire Scorpius-Centaurus complex is shown to possess a proper expansion with an angular velocity parameter of 46 ± 8 km s^?1 kpc^?1 for the kinematic center with l ₀ = ?40° and R ₀ = 110 pc found. Based on this velocity, we have estimated the characteristic expansion time of the complex to be 21 ± 4 Myr. The proper rotation velocity of the Scorpius-Centaurus complex is lower in magnitude, is determined less reliably, and depends markedly on the data quality.     

基于三代测序技术的凡纳滨对虾(Litopenaeus vannamei)高通量候选基因关联分析方法的建立

凡纳滨对虾(Litopenaeusvannamei)是世界也是我国的主导对虾养殖品种,产业的发展离不开良种的支撑,分子育种被认为是加快良种选育的最有效途径,而目标性状相关分子标记的开发是发展分子育种的基础。研究主要目的是建立一种适用于凡纳滨对虾等水产经济物种的高通量候选基因关联分析方法,并在抗弧菌相关标记筛选中进行应用。首次将三代靶向测序技术用于对虾候选基因的基因分型,在抗弧菌性状候选基因LvPI3K的全长序列上发掘到91个SNP位点,通过关联分析鉴定到21个与抗弧菌性状显著相关的SNP标记(P0.05),利用Sanger测序证实了三代靶向测序技术分型结果准确可靠。所建立的基于三代测序的靶向分型方法为凡纳滨对虾等水产动物提供了一种高效、低成本的基因分型方法,所发掘的抗弧菌性状相关位点对开展凡纳滨对虾抗弧菌性状分子育种具有一定指导意义。     

Study of hydrological processes by the combination of environmental tracing and hill slope measurements: application on the Haute‐Mentue catchment

The objective of this research is to improve the comprehension of the hydrological behaviour of natural catchments. The main originality of this work is to associate different types of measurement in order to obtain a better vision of hydrological processes responsible for streamflow generation. First, the hydrological behaviour is studied at the catchment scale by the application of environmental tracing. A three‐component mixing model based on the silica and calcium concentrations of water allows one to distinguish the contributions of direct precipitation, soil water and groundwater during flood generation. Despite the different hydrological responses observed between the four subcatchments studied, a common behaviour is apparent. Soil contribution increases with a rise in the basin humidity. The subsurface water dominates the generation of major floods, which occur in wet conditions. In order to discover the processes responsible for the important soil water contributions, a large‐scale time‐domain reflectometry experiment (64 probes) was conducted. On the whole, this experiment indicates that the water flow in soil is spatially quite heterogeneous and depends on local properties. Macropore flows were clearly identified during a rainfall simulator experiment. Preferential flows may be responsible for the important contribution of soil water and the heterogeneity of the soil moisture. In order to test this hypothesis, a dye‐tracing experiment was done. This new investigation confirms that an important part of soil water reaches the stream by preferential flows. So as to synthesize all these observations, a conceptual model is proposed. This model respects both the hydrochemical responses highlighted by the environmental tracing experiment and the observations done at the local scale. This conceptual model suggests that the important contribution of soil water is due to the extent of the hydrographic network and the role of preferential flows. Copyright © 2005 John Wiley & Sons, Ltd.     

Ecological and social constraints are key for voluntary investments into renewable natural resources

Encouraging pro-environmental behavior is an urgent global challenge. An interdisciplinary framework covering governance, economic, social, ecological, and psychological dimensions is required to understand the salient features that encourage pro-environmental outcomes within and across contexts. We apply the Ostrom social-ecological systems framework to model voluntary investments by members of civil society into the aquatic environment. Using a data set of 1,809 angling clubs managing water bodies for fish stocking and habitat management in Germany and France, we show that a small set of factors, most crucially social-ecological and governance context as well as social norms and other bottom-up social pressures, drive environmental investments. These factors appear to override behavioral influences from psychological variables of the decision-maker. By contrast, the contextual setting related to property rights, size of the resource system, and social expectations were found to be strongly related to behavioral decisions, highlighting that the social-ecological context as well as incentives may be more important than knowledge and cognitions in driving certain pro-environmental actions.     

基于饱和约束和时变观测器设计的异构航天器姿态控制策略

针对空间异构环境下易产生非线性和不确定性影响,多个异构航天器进行姿态控制存在执行器输入饱和约束,对有限的资源进行协作调度难度大等问题,提出了异构航天器包含饱和输入和不确定性动态的鲁棒一致性追踪控制策略.在该控制策略中,参考系统的动态权重矩阵被允许是完全未知的,因此现有的方法并没有可行解.通过引入有向生成树假设,一种新的权重平均方法被提出来构造分布式观测器动态.通过综合分布式观测和非线性动态,一类新的鲁棒一致性追踪控制器被设计.仿真结果表明：当同步行为和分布式观测动态能够被同时获得并且达到领导者状态,异构系统的鲁棒一致性问题将被解决.同时,通过利用多个航天器的动态模型,设计了不同性能指标的参数条件,验证和分析了提出方法的有效性.     

Conservation in a complex management environment: The by-catch of sea turtles in North Carolina’s commercial fisheries

Despite a powerful, federal legislative framework established to protect threatened and endangered species in the United States, conservation actions can be hindered by the complexity of the full management structure. This is particularly true when state and federal agencies share the responsibility to conserve endangered species. To illustrate this point, this paper describes the management of sea turtle by-catch in commercial fisheries within the state waters of North Carolina. It reviews past and present by-catches, summarizes state and federal efforts intended to reduce sea turtle by-catch, and discusses the challenges posed by the involvement of multiple agencies with conflicting objectives. It concludes by recommending fundamental changes to this management framework and, in particular, proposes the establishment of a multilayered stakeholder group that would work to reduce sea turtle by-catch while supporting vibrant commercial fisheries in the state.     

Coordination of urbanization and water ecological environment in Shayinghe River Basin,China

During the rapid industrialization and urbanization of China,urban agglomeration in river basin areas raises the problems of over-use of water resources and pollution of the water environment.Related research in China has mainly focused on the conflicts among economic growth,urban expansion and water resource shortages within admin-istrative boundaries.However,water environments are much more dependent on their physical boundaries than their administrative boundaries.Consistent with the nature of water environment,this study aims at analyzing coordination relationships between urban development and water environment changes within physical river basin boundaries.We chose the Shayinghe River Basin,China,as our case study area which is facing serious challenges related to water en-vironment protection.Then we classified 35 county-level administrative units into upstream,midstream and down-stream regions based on their physical characteristics;analyzed the coordination degree of urban agglomeration using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method;and constructed cooperative models using the Linear Programming (LP function) to simulate four scenarios of the coordination relationship be-tween urban population increase and water environment protection based on existing water resources and water pollu-tion data.The results show that the present coordinative situation in Shayinghe River Basin is not sustainable.In gen-eral,more than 50% administrative units are in the bad coordinative situation.In particular,the downstream region is under worse condition than the upstream and midstream regions.Cooperative models in scenario analyses indicate that the population scale set in existing urban master plannings is not coordinated with the water environment protection.To reach the goal of regional sustainable development,the total population needs to be controlled such that it will re-main at 4.5×10 7 or below by 2020 given the capacity of water environment.