欠发达农区外出务工规模及影响因素分析

根据对河南省农区十村11251 户农户的入户调查资料,认为农民外出务工的数量与规模是经济因素、家庭 因素和环境因素综合作用的结果。多元回归模型显示：①外出务工经济收益与成本、家庭人口状况、农户家庭经营 地、农户家庭生活性支出等正向影响农户外出务工的规模;②农区家庭劳动力文化状况中,初中及以下学历人数正 向影响农区外出务工的规模,高中及以上学历人数负向影响农区外出务工的规模;③环境因素中,经济水平因子对 农区外出务工规模的影响是正向的,地形、通达性和土地类型等三个因子对农区外出务工规模的影响是负向的。     

Evaluation of an empirical orthogonal function–based method to downscale soil moisture patterns based on topographical attributes

Soil moisture influences many hydrologic applications including agriculture, land management and flood prediction. Most remote‐sensing methods that estimate soil moisture produce coarse resolution patterns, so methods are required to downscale such patterns to the resolutions required by these applications (e.g. 10‐ to 30‐m grid cells). At such resolutions, topography is known to affect soil moisture patterns. Although methods have been proposed to downscale soil moisture based on topography, they usually require the availability of past high‐resolution soil moisture patterns from the application region. The objective of this article is to determine whether a single topographic‐based downscaling method can be used at multiple locations without relying on detailed local observations. The evaluated downscaling method is developed on the basis of empirical orthogonal function (EOF) analysis of space–time soil moisture data at a reference catchment. The most important EOFs are then estimated from topographic attributes, and the associated expansion coefficients are estimated on the basis of the spatial‐average soil moisture. To test the portability of this EOF‐based method, it is developed separately using four data sets (Tarrawarra, Tarrawarra 2, Cache la Poudre and Satellite Station), and the relationships that are derived from these data sets to estimate the EOFs and expansion coefficients are compared. In addition, each of these downscaling methods is applied not only for the catchment where it was developed but also to the other three catchments. The results suggest that the EOF downscaling method performs well for the location where it is developed, but its performance degrades when applied to other catchments. Copyright © 2011 John Wiley & Sons, Ltd.     

Cavity expansion in cross‐anisotropic rock

Schistous rock can be considered—in a first approximation—as cross‐anisotropic linear elastic material. The determination of the corresponding material constants on the basis of the laboratory investigation of rock samples often fails, as the extraction of appropriate cores proves to be unfeasible (the cores disintegrate if the schistosity is pronounced). In this paper a new method is presented to determine the material constants of a linear elastic cross‐anisotropic rock on the basis of cavity expansion field tests, e.g. with a radial jack. To this purpose, an analytic approximation for the deformation of a hydrostatically loaded cylindrical cavity in cross‐anisotropic rock is derived which serves to the inverse analysis of the material parameters. Copyright © 2010 John Wiley & Sons, Ltd.     

Large-scale cold water dispersant effectiveness experiments with Alaskan crude oils and Corexit 9500 and 9527 dispersants

There continues to be reluctance in some jurisdictions to use chemical dispersants as a viable countermeasure for accidental oil spills. One argument used by some opponents to dispersant use is that “chemical dispersants do not work effectively in cold water”. To address this issue, the U.S. Minerals Management Service (MMS) funded and conducted two series of large-scale dispersant experiments in very cold water at Ohmsett - The National Oil Spill Response Test Facility, located in Leonardo, New Jersey in February-March 2006 and January-March 2007. Alaska North Slope, Endicott, Northstar and Pt. McIntyre crude oils and Corexit 9500 and Corexit 9527 dispersants were used in the two test series. The crude oils were tested both when fresh and after weathering. Results demonstrated that both Corexit 9500 and Corexit 9527 dispersants were 85-99% effective in dispersing the fresh and weathered crude oils tested at cold temperatures. The MMS expects that results from these test series will assist government regulators and responders in making science based decisions on the use of dispersants as a response tool for oil spills in the Arctic.     

Monitoring qualitative spatiotemporal change for geosensor networks

Recent technological advances in geosensor networks demand new models of distributed computation with dynamic spatial information. This paper presents a computational model of spatial change in dynamic regions (such as may be derived from discretizations of continuous fields) founded on embeddings of graphs in orientable surfaces. Continuous change, connectedness and regularity of dynamic regions are defined and local transition rules are used to constrain region evolution and enable more efficient inference of a region's state. The model provides a framework for the detection of global high‐level events based on local low‐level ‘snapshot’ spatiotemporal data. The approach has particular relevance to environmental monitoring with geosensor networks, where technological constraints make the detection of global behaviour from local conditions highly advantageous.     

Modeling of circulation and salinity in Hooghly estuary

The circulation and salinity distribution in the Hooghly Estuary have been studied by developing a two‐dimensional depth‐averaged numerical model for the lower estuary, where the flow is vertically well mixed. This has been coupled with a one‐dimensional model for the upper estuary, where the flow is assumed to be unidirectional and well mixed over the depth and breadth. The Hooghly River receives high freshwater discharge during the monsoon season (June to September), which has significant effect on the salinity distribution in the estuary. The model‐simulated currents, elevations, and salinities are in good agreement with observations during the dry season. However, during the wet season the computed salinities seem to deviate slightly from the observed values.     

潼峪金矿区成矿断裂构造特征

潼峪金矿区发育过冲剪滑型、平移剪张型和平移剪滑型三种不同性质、不同方向成矿断裂,分布在金罗斑背形的不同部位,其形成有先后差异,但变形环境大体相同,具脆-韧性变形特征。空间上一般不超越褶皱主体。三类断裂中,前两者具石英脉型金矿化,后者形成构造蚀变岩型及小规模石英脉型金矿化。矿化差异与断裂产出的褶皱部位及其相应的应力应变条件的不同有关。     

Scale effects in food environment research: Implications from assessing socioeconomic dimensions of supermarket accessibility in an eight-county region of South Carolina

Choice of neighborhood scale affects associations between environmental attributes and health-related outcomes. This phenomenon, a part of the modifiable areal unit problem, has been described fully in geography but not as it relates to food environment research. Using two administrative-based geographic boundaries (census tracts and block groups), supermarket geographic measures (density, cumulative opportunity and distance to nearest) were created to examine differences by scale and associations between three common U.S. Census–based socioeconomic status (SES) characteristics (median household income, percentage of population living below poverty and percentage of population with at least a high school education) and a summary neighborhood SES z-score in an eight-county region of South Carolina. General linear mixed-models were used. Overall, both supermarket density and cumulative opportunity were higher when using census tract boundaries compared to block groups. In analytic models, higher median household income was significantly associated with lower neighborhood supermarket density and lower cumulative opportunity using either the census tract or block group boundaries, and neighborhood poverty was positively associated with supermarket density and cumulative opportunity. Both median household income and percent high school education were positively associated with distance to nearest supermarket using either boundary definition, whereas neighborhood poverty had an inverse association. Findings from this study support the premise that supermarket measures can differ by choice of geographic scale and can influence associations between measures. Researchers should consider the most appropriate geographic scale carefully when conducting food environment studies.     

中国工业结对集聚和空间关联性分析

要推动形成优势互补高质量发展的区域经济布局,就需要从产业关联视角考察中国工业的空间格局.集聚是工业在空间的重要表现形式,通过把测度两两配对产业集聚的结对集聚指数和测度两两配对产业关联度的投入产出表相结合,首次构建集聚关联指数和关联集聚指数,以研究不同空间尺度下空间关联性的差异和出现差异的原因.通过整理中国工业企业数据库...     

尺度政治理论框架

目前国内外对尺度及尺度政治的讨论十分热烈。本文在整合已有研究的基础上,基于主体与结构视角提出了一个三阶段的尺度政治理论框架,指出政治过程和权力结构的尺度化是尺度政治的前提,尺度重构是尺度政治的核心机制,权力关系重构是尺度政治的目的和结果。具体而言,尺度化涉及物质空间、组织空间和表达空间的大小、层级、范围等结构关系;尺度重构包含由尺度上推、下推、重组,以及上述不同尺度形式构成的3×3矩阵;不同政治主体会采用特定尺度重构策略改变权力关系,并造成一系列尺度关系和合法性的悖论。基于以上认识,本文进一步讨论了中西方关于尺度和尺度政治的认知差异和未来值得深入研究的课题。