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1.
金星探测研究进展与未来展望   总被引:1,自引:0,他引:1  
金星探测是解答太阳系类地行星形成演化,地球宜居性的形成和未来发展,以及外太阳系宜居星球搜索策略的关键.由于金星恶劣的环境条件、对探测技术的多重挑战和相对高昂的探测成本,金星探测和研究程度远不及月球和火星.自20 世纪90 年代后期,金星探测任务相对匮乏.本文梳理了国际上金星探测研究进展、关键科学问题及技术需求,提出了未...  相似文献   

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《China Geology》2019,2(2):198-210
Mineral potential assessment at the Earth’s surface has been an important research for geoscientists around the world in the past five decades. The fundamental aspects of mineral assessment at different scales can be associated with the following tasks, e.g., mineral potential mapping and estimation of mineral resources. This paper summarized the history and development in terms of theories, methods technologies and software platforms for quantitative assessment of mineral resources in China, e.g. comprehensive information methodology, geological anomaly, three-component quantitative prediction method, 5P ore-finding area, integrated information assessment method, nonlinear process modeling and fractals, three dimensional mineral potential mapping, etc. At last, to discuss the future of quantitative mineral assessment in an era of big data including platform for 3D visualization, analysis and sharing, new methods and protocols for data cleaning, information enhancement, information integration, and uncertainties and multiple explanations of multi-information.© 2019 China Geology Editorial Office.  相似文献   

4.
刘连刚 《城市地质》2015,(Z1):13-17
本文在阐述北京市地质灾害的基本状况的基础上,对北京市几十年来地质灾害从被动避防到主动防灾,再到防灾体系初步形成不同阶段历程的防治工作进行了回顾总结。对北京市城市运行的地质安全.地质灾害防治与应急管理,提升公众防灾减灾意识等方面的需求进行了多角度的分析:从完善防灾保障体系、建立技术支撑体系.健全群防群治体系等几个方面,对北京市地质灾害防治进行了展望。  相似文献   

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The objective of this paper is to engage constructively with literature on armed conflict and resources in order to draw attention both to assumptions that hinder a more accurate or useful understanding of natural resources and their role in territorial conflict as well as to aspects of this field of research that merit further work. In much of the literature on resource conflict, territorial aspects are either implicitly or explicitly tied to resource conflict largely through the assumption that the value of territory is intrinsic. Little of the literature attempts to advance theory, specifically, either on the particular role of resources or on the meaning and objectives of conflict beyond a one-dimensional objective of maintaining or securing control of territory. The paper considers themes of resource scarcity and resource abundance in conflict. A third section focuses on an analysis both of natural resource databases and of conflict databases (both international and civil) which emphasizes problematic results of blending these databases to demonstrate correlations. UIUC territorial conflict management workshop  相似文献   

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In 1991 the New Zealand health system began to experience what has been termed the `turbulent decade'. Without health sector consultation or public mandate, an era of imposed market oriented reforms began. These changed the overall culture of health care delivery and the expectations of New Zealanders regarding the role of the state in the provision of welfare. In retrospect the ideologically driven imposition of the market-oriented reforms was not an exercise of bold leadership but one of political arrogance and rejection of established community values. Within the community, the neoliberal experiment heightened income and health inequalities, created a loss of social cohesion and generally provoked feelings of powerlessness. In the health sector, the reforms polarised clinical and commercial cultures and changed the geography of health care delivery. This occurred not only because place was de-emphasised, but also because decentralisation of purchasing created four health systems with widely divergent contracting arrangements and standards of care. The lessons of the health reforms have been painful, and must not be lost. A fundamental lesson is that market approaches to the delivery of health care have major limitations and that the ultimate goal of a health system should be the equitable, effective and efficient provision of care, not the profitable sale of commodities. Since 1997 there has been a retreat from the market, although it is not clear whether recent policy developments represent a new or distinctive `third way' or a pragmatic `pick and mix', combining the best from the market and the managerialism first introduced by Labour in the 1980s. Quite clearly, the experiment with the market was not sustainable. Whether this will also be true of the more recent and pragmatic `pick and mix' approach of the `third way' to health care reform is uncertain. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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Sasha Tsenkova 《GeoJournal》2014,79(4):433-447
The paper provides an overview of trends and processes of change affecting new social housing provision in Prague and Warsaw. The local responses are reviewed within the context of changes to the national housing system defining the performance of municipal and non-profit housing sectors. The research analyses the mix of policy instruments implemented in three major policy domains—regulatory, fiscal and financial—to promote the production of new social housing in the two cities. The system of new social housing provision is examined as a dynamic process of interaction between public and private institutions defining housing policy outcomes. The outcomes are evaluated through a series of indicators related to housing output, stability of investment, differentiation of rents, affordability and choice. The overview demonstrates how significant shifts in regulatory and fiscal policy, coupled with decentralization of responsibilities for social housing, limit the opportunities for more efficient performance in the sector and its growth. This is particularly evident in Warsaw, where the sector operates as a social safety net. New social housing in both cities has better quality and remains affordable, but access is constrained and waiting times have increased. The research highlights the problem of declining output, dwindling financial resources, and lack of cost recovery due to universal rent control. This is eroding the sustainability of social housing, potentially leading to lower investment and subsequent privatisation. In Warsaw, housing allowances are a municipal responsibility making the liberalization of rents difficult, while Prague has moved in the direction of rent deregulation with a more robust system of means-tested housing support provided by the central government. Such policy choices map a different trajectory for the future of social housing.  相似文献   

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Igor Vrišer 《GeoJournal》1996,38(2):151-156
An important state sector developed in Slovenian agriculture under communism and although it accounted for a less than a tenth of the agricultural area it assumed a major role in supplying food to the urban markets; also in providing raw material to the food processing industry and for exporting. In the context of the transition to a market economy legislation has been enacted that provides for denationalisation and the restructuring of enterprises. This threatens the survival of the state sector and creates problems for the food market because the private farmers are not yet well-organised to provide an alternative supply. The government is committed by the legislation already passed but is anxious to avoid marketing problems.  相似文献   

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Deep-water agglutinated Foraminifera (DWAF) display potential for correlating pelagic (calcareous and non-calcareous) and flysch environments. This is illustrated by an example from Sites 765 and 261 on the Argo Abyssal Plain. A working zonation based on DWAF has been developed for Lower Cretaceous flysch sequences of the Polish Carpathians, but this zonal scheme has not been tested in other areas of the Tethys. No zonation has yet been developed for abyssal oceanic DWAF. The challenge for the future, under the auspices of Project 262, is to test the existing zonation in other regions and develop a widely applicable biochronology for integration into a general Tethyan biochronological correlation scheme.  相似文献   

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花岗岩暗色微粒包体特征及其研究方向   总被引:3,自引:0,他引:3       下载免费PDF全文
通过调研近年来国内外学者对于花岗岩类中暗色微粒包体的研究成果,总结了其野外地质、岩相学、地球化学和同位素等特征以及成因研究中的主要问题。暗色微粒包体(MME)广泛分布于I型花岗岩中,一般呈随机分布,形态多样,但以塑性特征为主;一般认为是岩浆混合成因,其原始物源是玄武质岩浆,具典型的火成岩结构,发育针状磷灰石、环带结构和筛状结构的斜长石;相对于寄主岩石,暗色微粒包体富Fe,Mg,贫Si,Na,其锆石U-Pb年龄在误差范围内与寄主岩石年龄一致等,反映了壳幔源岩浆的混合事件。暗色微粒包体与岩浆动力学行为、矿化关系及区域地质演化等方面值得进一步研究、探索。  相似文献   

11.
张新安  刘丽  郭文华  张迎新 《地质通报》2009,28(2-3):166-170
分析了加强国土资源综合调查评价的目的和意义,探讨了中国国土资源调查评价中存在的突出问题。在对国际经验和国内探索实践进行对比分析的基础上,提出了加强中国国土资源综合调查评价的战略构想,即先易后难,循序推进;综合权衡,选准切入口。  相似文献   

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张新安  刘丽  郭文华  张迎新 《地质通报》2009,28(203):166-170
分析了加强国土资源综合调查评价的目的和意义,探讨了中国国土资源调查评价中存在的突出问题。在对国际经验和国内探索实践进行对比分析的基础上,提出了加强中国国土资源综合调查评价的战略构想,即先易后难,循序推进;综合权衡,选准切入口。  相似文献   

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Woodcutting and territorial claims in Mali   总被引:2,自引:0,他引:2  
In Mali, amidst moves toward political decentralization and the transfer of authority to manage natural resources, woodcutting has become an important tool for the assertion of territorial claims by villagers. The decentralization process has itself led to a profound political shake-up between the central state seeking to maintain land ownership and the de facto management of land by customary village authorities. But it is, however, primarily the devolution of forest resource management to village-led organizations that has prompted the cross-scale legitimization and assertion of various territorial claims from 1995 onwards. Based on two in-depth case studies on the outskirts of Bamako, Mali, the authors illustrate how new practices revolving around woodcutting and charcoal-making have been instrumental in intra- and inter-village disputes. At the village level, this transfer tends to exacerbate tenure claims over land and trees with the reactivation of autochthony-related arguments and thus the risk of excluding the most vulnerable social groups which are typically involved in woodcutting. At the inter-village level, this gives villages the opportunity to claim and demarcate boundaries by cutting, painting signs on some trees, or more radically tree felling being carried out solely to demonstrate appropriation. At the municipal level, this transfer leads to political and social adjustments between customary and decentralized authorities, each struggling to build their legitimacy in natural resource management.  相似文献   

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分析了加强国土资源综合调查评价的目的和意义,探讨了中国国土资源调查评价中存在的突出问题.在对国际经验和国内探索实践进行对比分析的基础上,提出了加强中国国土资源综合调查评价的战略构想,即先易后难,循序推进;综合权衡,选准切入口.  相似文献   

15.
This article examines an object-oriented geospatial information model for territorial system management, its benefits compared to current automated territorial management systems, and special aspects of its development and implementation in multi-level geoinformation systems. The presented study reflects the major functions of geoinformation materials used in spatial planning, particularly in Earth remote sensing. A territorial information management model is developed from the perspective of the object-oriented geoinformation approach. The study identifies the major functions of the proposed management system and demonstrates what kinds of problems can be solved using this system, develops a spatial algorithmic model for managerial decision-making and a methodology for analyzing local territorial system characteristics; and introduces basic information arrays that can be used to solve practical territorial management problems at various levels.  相似文献   

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Many Recent and fossil freshwater tufa stromatolites contain millimetre‐scale, alternating laminae of dense micrite and more porous or sparry crystalline calcites. These alternating laminae have been interpreted to represent seasonally controlled differences in the biotic activity of microbes, and/or seasonally controlled changes in the rate of calcification. Either way, couplets of these microbially mediated alternating calcified laminae are generally agreed to represent annual seasonality. Combined stable isotope (δ18O and δ13C) and trace element (Mg, Sr, Ba) geochemistry from Recent tufa stromatolites show that seasonal climatic information is available from these calcites. Variability in δ18O (and in one case Mg concentration) has been shown to be controlled primarily by stream temperature change, usually driven by solar insolation. In arid climates, seasonal evaporation can also cause δ18O enrichment by at least 1‰. Variability in δ13C results potentially from: (1) seasonal change in plant uptake of 12C‐enriched CO2; (2) seasonal change in degassing of 12C‐enriched CO2 in the aquifer system; and (3) precipitation of calcite along the aquifer or river flow path, a process that increases δ13C of dissolved inorganic carbon (DIC) in the remaining water. Mechanisms 2 and 3 are linked because calcite precipitates in aquifers where degassing occurs, e.g. air pockets. The latter mechanism for δ13C enrichment has also been shown to cause sympathetic variation between trace element/Ca ratios and δ13C because trace elements with partition coefficients much greater than 1 (e.g. Sr, Ba) remain preferentially in solution. Since degassing in air pockets will be enhanced during decreased recharge when water saturation of the aquifer is lowest, sympathetic variation in trace element/Ca ratios and δ13C is a possible index of recharge and therefore precipitation intensity. High‐resolution geochemical data from well‐dated tufa stromatolites have great potential for Quaternary palaeoclimate reconstructions, possibly allowing recovery of annual seasonal climatic information including water temperature variation and change in rainfall intensity. However, careful consideration of diagenetic effects, particularly aggrading neomorphism, needs to be the next step. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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Early research on contentious issues in world politics suggested that there is an important distinction between largely tangible and largely intangible issues. Tangible issues are thought to be easier to resolve, while intangible issues can fester for long periods of time through fruitless negotiations and repeated armed conflict. Research on territorial issues has suggested that many territorial claims are driven by both tangible and intangible concerns, though, which complicates the analysis of issue tangibility. The authors argue that territorial issues with greater intangible salience (e.g. historical possessions, important homelands, sacred sites, identity ties) should be harder to resolve peacefully and should produce more frequent and severe militarized conflict. Empirical analyses of 191 territorial claims in the Americas and Western Europe (1816–2001) provide mixed support for these expectations. Territorial claims with high intangible salience are significantly more likely to experience militarized disputes and wars. Surprisingly, though, states are much more likely to strike peaceful agreements with their adversaries over territories that are valued for intangible reasons. *This research was supported by National Science Foundation grants SES-0079421 and SES-0214447.  相似文献   

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The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand‐sea or dunefield (erg) deposits, whereas coastal systems are primarily known from the Cenozoic. The complexity of aeolian sedimentary processes and facies variability are under‐represented and excessively simplified in current facies models, which are not sufficiently refined to reliably account for the complexity inherent in bedform morphology and migratory behaviour, and therefore cannot be used to consistently account for and predict the nature of the preserved sedimentary record in terms of formative processes. Archean and Neoproterozoic aeolian successions remain poorly constrained. Palaeozoic ergs developed and accumulated in relation to the palaeogeographical location of land masses and desert belts. During the Triassic, widespread desert conditions prevailed across much of Europe. During the Jurassic, extensive ergs developed in North America and gave rise to anomalously thick aeolian successions. Cretaceous aeolian successions are widespread in South America, Africa, Asia, and locally in Europe (Spain) and the USA. Several Eocene to Pliocene successions represent the direct precursors to the present‐day systems. Quaternary systems include major sand seas (ergs) in low‐lattitude and mid‐latitude arid regions, Pleistocene carbonate and Holocene–Modern siliciclastic coastal systems. The sedimentary record of most modern aeolian systems remains largely unknown. The majority of palaeoenvironmental reconstructions of aeolian systems envisage transverse dunes, whereas successions representing linear and star dunes remain under‐recognized. Research questions that remain to be answered include: (i) what factors control the preservation potential of different types of aeolian bedforms and what are the characteristics of the deposits of different bedform types that can be used for effective reconstruction of original bedform morphology; (ii) what specific set of controlling conditions allow for sustained bedform climb versus episodic sequence accumulation and preservation; (iii) can sophisticated four‐dimensional models be developed for complex patterns of spatial and temporal transition between different mechanisms of accumulation and preservation; and (iv) is it reasonable to assume that the deposits of preserved aeolian successions necessarily represent an unbiased record of the conditions that prevailed during episodes of Earth history when large‐scale aeolian systems were active, or has the evidence to support the existence of other major desert basins been lost for many periods throughout Earth history?  相似文献   

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杨保  王鑫  宋苗  王江林  史锋  方苗 《第四纪研究》2017,37(5):945-962

过去2000年气候变化研究是全球气候变化研究的核心内容,不仅可以提供20世纪气候增暖的自然背景,也是最终揭示20世纪气候变暖机理并预估未来气候变化趋势的关键途径,是国际大型计划(如PAGES,过去全球变化研究计划)的优先研究时段。近20多年来,特别是近几年,随着代用资料的不断积累和气候重建方法的改进和发展,过去2000年大尺度气候重建研究取得了长足发展,在区域和北半球气候集成重建方法,年际、年代、百年乃至千年时间尺度上的气候时空变化特征和机制,及最近几十年气候增暖的历史地位等方面的研究均取得了重要科学认识,形成了现代气候增暖机理和未来气候趋势预估的科学基础。本文主要从方法学、研究历史回顾和现阶段形成的科学认识等3个方面论述过去2000年气候变化研究取得的成就,并对未来的研究方向进行了展望。

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