A case study of coping strategies and landslides in two villages of Central-Eastern Nepal

Landslides are an increasing problem in Nepal’s Middle Hills due to both natural and human phenomena: mainly increasingly intense monsoon rains and a boom in rural road construction. This problem has largely been neglected due to underreporting of losses and the dispersed nature of landslides. Understanding how populations cope with landslides is a first step toward developing more effective landslide risk management programs. The present research focuses on two villages in Central-Eastern Nepal, both affected by active landslides but with different coping strategies. Research methods are interdisciplinary, based on a geological assessment of landslide risk and a socio-economic study of the villages using household questionnaires, focus group discussions and transect walks. Community risk maps are compared with geological landslide risk maps to better understand and communicate community risk perceptions, priorities and coping strategies. A modified typology of coping strategies is presented, based on previous work by Burton, Kates, and White (1993) that is useful for decision-makers for designing more effective programs for landslide mitigation. Main findings underscore that coping strategies, mainly seeking external assistance and outmigration, are closely linked to access to resources, ethnicity/social status and levels of community organization. Conclusions include the importance of investing in organizational skills, while building on local knowledge about landslide mitigation for reducing landslide risk. There is great potential to increase coping strategies by incorporating skills training on landslide mitigation in existing agricultural outreach and community forest user group training.     

洛阳市旅游资源的空间结构及其演化模式

通过对洛阳市旅游景点体系的集聚度、通达度和分异度指标分析,认为洛阳市旅游资源空间分布呈现整体均匀、中部集聚态势,景点网络的通达度有待提高。基于洛阳市旅游资源的密度和品位度空间分布等高线图,将洛阳市旅游资源化为3个核心-边缘单元:即洛阳——文化旅游资源体系、栾(川)嵩(县)——山岳旅游资源体系和新安——山水旅游资源体系。根据区域发展的离散阶段、成长阶段和成熟阶段,讨论了3个资源体系目前所处的阶段和边缘地区可能的发展趋势。     

武汉市碳排放的测算及影响因素分解研究

研究基于14个主要方面碳源,测算了武汉市1996—2009年碳排放量。发现自1996年以来武汉市碳排放呈现"平稳—上升—平稳"的三阶段特征。进一步基于LMDI模型分解碳排放的影响因素,结果表明,能源结构、能源效率因素对碳排放量具有一定抑制作用,但效果不够显著且波动性较强,1997—2009年与基期相比,能源结构、能源效率因素分别累计实现了0.95%,11.30%的碳减排;而经济因素与人口规模因素则对碳排放具有较强推动作用,分别累计产生了64.65%,19.65%的碳增量。最后,据此提出推进武汉市碳减排的对策建议。     

地理学的主要任务与研究方法——从整个科学体系的视角看地理科学的发展

所有科学的主要任务都是建立数学模型,如果地理学想要发展成为一门标准科学——而不是走"例外主义"的道路,根据简单的逻辑法则可以判断,地理学的主要任务也是建立数学模型。现代科学研究的方法包括数学理论、实验室实验和计算机模拟,其中数学方法和模拟实验必将是地理学研究的主要方法;至于实验室实验,可用调查取证进行有限度的补充。未来地理研究的数学规范化和定量分析主要借助后现代数学工具(分形几何学和混沌数学等),而模拟实验则需要倚重仿生数学理论和模型。     

基于GIS的深圳梧桐山林地增长预测与削减径流生态效益评估

基于2005年深圳市0.3 m分辨率的航片与梧桐山8个林地样方数据,通过ArcView软件平台,利用CITYgreen生态价值评估模型,计算2005年梧桐山林地削减径流的生态效益。并以2005年为初始年,以10年为周期,预测2015—2055年林地生长趋势与生态效益。结果表明:2015年、2025年、2035年、2045年与2055年梧桐山林地增长率分别为14.23%、12.27%、12.09%、11.68%、12.85%;2005年削减径流的生态效益为3.74亿元,2015年、2025年、2035年、2045年与2055年预测值分别为3.89亿元、4.03亿元、4.19亿元、4.35亿元与4.52亿元。林地生长与生态效益增长态势不均衡与不同树木的生命周期及其特性相关。     

技术创新对黄河流域城市绿色发展的影响研究

创新是推动黄河流域高质量发展的重要途径之一。利用2006—2018年黄河流域79个地级以上城市的面板数据,首先构建指标体系对各城市技术创新及绿色发展水平进行分析,其次通过面板计量模型深入探究技术创新对城市绿色发展的作用机理。研究表明：① 2006—2018年,黄河流域城市技术创新与绿色发展水平均得到明显提升,但空间差异显著,总体呈“下游>中游>上游”阶梯式递减特征。② 黄河流域城市技术创新对绿色发展总体上没有显著影响,但在加入技术创新的二次项后,两者之间呈现显著的“U”型非线性关系,即技术创新先抑制后促进城市绿色发展,这也验证了技术的“回弹效应”假说;③ 技术创新对黄河流域城市绿色发展的影响可以通过直接效应和间接效应共同体现,但这两种效应正好相反,即一个城市技术创新能力的提升对该城市绿色发展存在显著的“U”型（先抑制后促进）关系,但对邻近城市的作用呈现倒“U”型相反的关系。根据研究结论,从技术创新对城市绿色发展的直接效应和间接效应2个方面提出了相应的政策建议。     

居民城市公共安全感知与社区环境——基于北京大规模调查问卷的分析

新型冠状病毒肺炎疫情的爆发使得民众对公共安全问题的关注到了前所未有的程度,社区作为社会治理基本单元,在防疫减灾中所发挥的作用尤为突出.本文基于北京2019年城市体检问卷调查数据,采用多层线性模型检验个体属性及社区环境指标对公共安全感知的影响.研究发现,公共安全感知的差异主要来自个体属性的不同,老年人及健康状况一般或较差...     

全球地缘经济合作的空间模式与空间机理——基于商品贸易规模的实证研究

运用1996—2016年全球各国商品贸易规模的面板数据,借助探索性空间数据分析方法揭示全球地缘经济合作的空间模式,构建空间误差混合回归模型进一步解释全球地缘经济合作的空间机理,得出如下结论：① 全球地缘经济合作存在空间正相关,呈现出“核心-边缘”的空间模式,表现为板块化和多极化的发展趋势;② 全球地缘经济合作的空间依赖性受到生产要素流动与国际分工的传导与驱动,国家规模是地缘经济合作的基础因素,生产要素禀赋是地缘经济合作的内生动力,创新是地缘经济合作的引擎,政治脆弱性是地缘经济合作的壁垒,地缘经济合作的空间依赖性在创新要素跨国流动影响下趋于弱化;③ 中国需在空间上遵循“邻近国家-欧亚区域-全球范围”的三环递进原则,有层次地布局地缘经济资源,在内容上发挥规模优势和要素禀赋优势,强化科技创新国际竞争力,有差异地制定地缘经济政策,在策略上激发地缘经济对地缘政治的渗透效应,最大化地缘经济杠杆作用。     

Crack nucleation in saturated porous media

Crack nucleation has been the subject of important contributions in the last two last decades. However, it seems that few attention has been granted to the case of saturated porous media. This is the question addressed in the present paper which is devoted to nucleation in traction mode. From a physical point of view, nucleation is a sudden phenomenon, so that the material response is both adiabatic and undrained. In the spirit of the variational approach, the nucleated crack is viewed as the final state of a region of space in which the material undergoes a full damage process. In traction mode, the opening of a saturated crack in undrained condition induces a drop of fluid pressure. In case of low fluid compressibility, the presence of the fluid delays the brittle failure usually associated with nucleation, as long as the fluid pressure remains above the saturation vapor pressure. Nucleation is therefore possible only if a partial vaporization of the fluid takes place.     

A plasticity constitutive model for unsaturated,anisotropic, nonexpansive soils

The paper describes and evaluates an incremental plasticity constitutive model for unsaturated, anisotropic, nonexpansive soils (CMUA). It is based on the modified Cam-Clay (MCC) model for saturated soils and enhances it by introducing anisotropy (via rotation of the MCC yield surface) and an unsaturated compressibility framework describing a double dependence of compressibility on suction and on the degree of saturation of macroporosity. As the anisotropic and unsaturated features can be activated independently, the model is downwards compatible with the MCC model. The CMUA model can simulate effectively: the dependence of compressibility on the level of developed anisotropy, uniqueness of critical state independent of the initial anisotropy, an evolving compressibility during constant suction compression, and a maximum of collapse. The model uses Bishop's average skeleton stress as its first constitutive variable, favouring its numerical implementation in commercial numerical analysis codes (eg, finite element codes) and a unified treatment of saturated and unsaturated material states.