Road lateral disconnection and crossing impacts in river landscape of Lancang River Valley in Yunnan Province, China

Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.     

Landscape network approach to assess ecological impacts of road projects on biological conservation

Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and animals in natural habitats.In this study,we evaluated the effects of different road construction scenarios on animal species movement by using the methods of ecological landscape connectivity in the typical regions of Yunnan Province,China.The results showed landscape connectivity levels（Probability of Con-nectivity（PC）） decreased after road construction and species with lower dispersal abilities were more affected to the subsequent habitat fragmentation.First level roads affected landscape connectivity most significantly.At a distance of 100 m,the PC index decreased more than 50%.Further analysis suggested that the use of landscape connectivity to assess landscape processes revealed the adverse effects on the species movement more effectively compared with the traditional landscape pattern analysis.In addition,we conducted a graph the-ory and a least-cost modeling discussion,it is obvious that they are powerful tools to represent and analyze landscape networks with respect to related species movement.Network analysis offers a quantitative and simple but effective tool for ecological process assess-ment and biological conservation on large scales.     

被动声呐的高分辨率目标方位估计

本文讨论应用高分辨率非线性谱分析技术进行水声目标方位的估计。文中针对水声信号特点，通过主值频谱抽取方法克服宽频带非线性方位估计的大运算量难题，大大简化了计算复杂性，同时还保证了较高的信噪比。经模拟计算表明，该方法实现简单，有较常规波束形成法为高的方位分辨率     

四川微观前兆异常的出现率和演化状态的分析

本文根据年震情会商研究中事前确认的观测异常项，研究了四川主要微观前兆手段和单台项异常的自然出现率和有震条件概率，为今后四川地震趋势和重点监视区的震情判断提供了较为可靠的一种信度估计。并利用32个观测项的前兆异常系统状态熵的分析，在一定程度上呈现了这些前兆变化与孕震过程的联系，给出了一种综合预报的思路和算法。     

层次分析法及其地面沉降研究应用

层次分析法是系统工程中的一种决策分析方法。本文应用其基本原理与方法对上海地面沉降进行了分析。     

Nd isotopic stratigraphy of Paleoproterozoic to late Paleozoic sedimentary strata of the southwestern Yangtze Block and implications for its tectonic evolution

ABSTRACT

A systematic Sm-Nd isotopic study is reported for Paleoproterozoic to Late Paleozoic strata from the Dongchuan area in the southwestern Yangtze Block. The results, combined with the available detrital zircon U-Pb ages and Hf isotope data, constrain the provenances of these sedimentary rocks and further identify three important tectono-magmatic activities. Most of the Paleo-Mesoproterozoic samples (Dongchuan Group) display a wide T_DM2 range of 1.92–2.52 Ga with corresponding ε_Nd(t) values of +4.0 to ?3.5, suggesting Paleoproterozoic-dominated provenances mixed with mantle-derived materials. This corresponds to the ~1.7–1.5 Ga mafic magmatic activities commonly occurred in the southwestern Yangtze Block, which are related to the early breakup of the Columbia supercontinent. The obvious vale of T_DM2 and apex of ε_Nd(t) occurred in the Neoproterozoic strata (~0.8 Ga) of the southwestern margin over the whole Yangtze Block. This is consistent with the widely recognized mantle-derived magmatism around the Yangtze Block related to the breakup of Rodinia. However, the decreases in Nd model ages are different among various regions, indicating that the Neoproterozoic mantle inputs are more profound in the southwestern and central Yangtze Block than the southeastern Yangtze and the Jiangnan orogenic belt. The late Ediacaran to early Cambrian strata from the southwestern Yangtze exhibit a decrease in T_DM2 (from 2.00 to 1.67 Ga) and increase in ε_Nd(t) (from ?9.0 to ?5.2). This is in accordance with the coeval juvenile crustal materials discovered in the northwestern Yangtze, which were probably derived from the assembly of the Gondwana continent. Thus, a Gondwanan affinity is suggested for the southwestern Yangtze Block. Overall, the Nd isotopic studies of the Paleoproterozoic to Late Paleozoic sedimentary strata from the southwestern Yangtze Block identified three major episodes of magmatic activities, late Paleoproterozoic (~1.7 Ga), Neoproterozoic (~0.8 Ga) and late Neoproterozoic-early Cambrian (~0.55 Ga) in the context of Columbia, Rodinia and the subsequent Gondwana supercontinents.     

Numerical Simulation of the Lagging Water Inrush Process from Insidious Fault in Coal Seam Floor

Because of insidious fault’s concealing performance and lagging nature, water inrush from insidious faults in coal seam floor can cause great threads to the mine safety. Based on analyzing the engineering geology conceptual model, this paper simulated the insidious fault lagging water inrush process and showed the lift height of the confined water in the insidious fault fractured zone (LHCWIFFZ) and the formation of water inrush channel. Then the concept of the potential water inrush channel with time effect was put forward. In order to further illustrate the time effect of the lagging water inrush from insidious fault, theoretical analysis was made from two aspects of the time effect of the plastic zone development height in the insidious fault fractured zone (PZDHIFFZ) based on the differential flow deformation theory and the time effect of water inrush channel in the upper part of the insidious fault (WICUPIF) based on the subcritical crack propagation theory. Simulation results showed that the results are basically consistent with mining practice.     

Spatial distribution of trace elements associated with organic carbon along the Beiyun River basin,Beijing,China

Pollution resulting from terrestrial and aquatic trace elements has become a severe problem across the world. Organic carbon(OC) content has a high affinity for metallic contaminants and it acts as a significant sink for trace elements. The decomposition of OC content directly influences the bioavailability of trace elements. The decomposition of OC content and OC distribution vary spatially, these processes affect the release of trace elements and need further research. In the current study, se...     

Geospatial assessment of agroecosystem health: development of an integrated index based on catastrophe theory

Assessing agroecosystem health at landscape scale has been rarely reported. A geospatial assessment framework, by integrating remote sensing, geographical information systems, landscape metrics, geostatistics and catastrophe theory, was proposed and applied to characterize the spatial variations of agroecosystem health for a typical region in the eastern coastal agricultural plain, China. After appropriate pretreatments, eleven hierarchically structured indicators, subject to catastrophe models, were aggregated into an integrated index for each 30 m grid cell across the study area. Great spatial variations in agroecosystem health were identified. Areas covered by water bodies and impervious surfaces, under which soils can not function, generally presented low values. Larger slope or higher heavy metal polluted areas and those near roads showed low or moderate values of agroecosystem health index. Concerning the spatial variations of agroecosystems health, patches of approximately 4 km in diameter were identified, within which more homogenous patterns would be expected. Specifically, the spatial variations of agroecosystems health should be resulted from the location-specific coupled influences of the underlying indicators. The integrated agroecosystem health index is believed to be helpful for managers to promote environmental management. The geospatial assessment framework reported in this paper was simple and operational, and has potential to be applicable to other areas with similar conditions at landscape scale.     

Spatiotemporal dynamics of soil erosion risk for Anji County, China

Soil erosion, as a serious environmental problem worldwide, poses a great threat to human sustainability. Spatiotemporal information on soil erosion is of vital importance to finding a solution for this problem. A case study was conducted to characterize the dynamics of soil erosion risk in 1985, 1994, 2003 and 2008 for Anji County, China, a region with seemingly high ecological quality. Remote sensing and geographic information systems were integrated to parameterize soil erosion-controlling factors. By using the Revised Universal Soil Loss Equation, we estimated annual soil loss, and generated categorical maps of soil erosion risk in the County for the 4?years. Results showed that, while appearing to improve in some areas, soil erosion risk increased and eroded area expanded from 1985 to 2008. Spatial analysis revealed that the most vulnerable hotspots were erosion-free forests, where newly eroded areas were most likely to occur. These results implied that, similar to findings in many parts of the world, soil erosion is an important issue in the study area, which could be closely associated with local eutrophication and algal blooms. Our research indicated that there should be more focus on this issue. From a methodological point of view, we believe that the approach used to estimate soil loss in the study area has the potential to be applied in other similar regions.