带约束折线的平面散点集Delaunay三角剖分

首先将原始散点与约束点一起进行三角剖分,形成初始Delaunay三角网,然后再将各条约束线段通过局部更新,依次嵌入已存在的三角网中,从而生成带有约束折线的平面散点集的Delaunay三角剖分。该算法思路简捷,易于编程,生成的三角网形态优良。     

Development and application of antibody microarray for white spot syndrome virus detection in shrimp

Detecting white spot syndrome virus (WSSV) in shrimp in high efficiency and veracity is important for disease prevention in aquaculture. Antibody-based microarray is a novel proteomic technology that can meet the requirements. In this study, we developed an antibody microarray for WSSV-detection in a specific and parallel way at multiple samples. First, seven slides each with different modifications were characterized by atomic force microscope, and were compared in the efficiency of immobilizing proteins. Of the seven, 3-dimensional structured agarose gel-modified slides were chosen appropriate for the microarray for having higher signal value and superior spot size. A purified rabbit anti-WSSV antibody was arrayed as the capture antibody of the microarray on the agarose gel-modified slides, and then the microarray slides were incubated in the tissue homogenate of sampled shrimp and the antibody-antigen complex was detected by Cy3-conjugated anti-WSSV monoclonal antibody. The results were measured by a laser chipscanner and analyzed with software. To obtain satisfied fluorescence signal intensity, optimal conditions were searched. The detection limit of the antibody microarray for WSSV is 0.62 μg/mL, with a proven long shelf life for 6 months at 4°C or 8 months at -20°C. Furthermore, concordance between antibody microarray and traditional indirect ELISA reached 100% for WSSV detection. These results suggest that the antibody microarray could be served as an effective tool for diagnostic and epidemiological studies of WSSV.     

应用主分量分析法研究唐山Ms7.8地震前的地磁异常

应用主分量分析法对昌黎、青光、宝坻、红山等台站(1975—1977年)三年的每月五个静日地磁绝对磁场的资料及相应时间的太阳黑子相对数的资料进行计算。结果表明,第一主分量与太阳黑子相对数对应很好,相关系数为0.9以上,而第二主分量与太阳黑子相对数的相关系数为0.03左右。对于在某一固定频率而变化的地磁外源场,内外场的比例几乎恒定在一定水平上,而在唐山地震前内外场比值有明显的异常变化,笔者认为,这个恒定水平的偏离可能是由于地壳内应力不断积累导致的地下电导率的变化而引起的。用这种方法不仅可以消除地磁场的非局部变化,而且利用内外场比值的偏离或监视内场的变化可能为使用地磁场预报地震提供一个依据。     

Adaptive Strategies to Displacement and Environmental Change Among the Kaiabi Indigenous People of the Brazilian Amazon

Environmental change, geographical displacement, and disputes over land and resources have increased around the world. This article focuses on strategies developed by the Kaiabi indigenous people to cope and adapt to environmental change after development-forced displacement and resettlement in the Brazilian Amazon. A mixed methods approach was adopted, combining ethnographic and quantitative methods. Semistructured interviews were performed among 214 individuals in a study on the dynamics of indigenous knowledge (IK) and natural resource management across three Kaiabi lands. We identified seven main coping and adaptive strategies developed by the displaced group: leadership and reciprocity networks, mobility, maintenance and innovation of native language, knowledge articulation, substitution of strategic resources, transmission across genders, and revitalizing diversity. These strategies have helped to enhance social–ecological resilience at different scales. Policies for resettlement and adaptation to environmental change must be developed with indigenous communities based on local knowledge and institutions.     

Patterns of Changes to Woody Vegetation near Resettlement Sites in Semi-arid Northwestern Ethiopia

Communal rangelands provide diverse ecosystem services to millions of pastoralists and agro-pastoralists. Resettling destitute communities into hitherto uninhabited communal rangelands and forests, a common practice throughout Sub-Saharan Africa, is a threat to the sustainable use of range and forest land resources. In order to understand the effect of resettlement on a semi-arid woodland in northwestern Ethiopia, satellite imagery of 23 resettlement villages taken over a period of fourteen years, and woody vegetation floristic data for three old resettlements, three new resettlements, two refugee camps and one protected area were analyzed using ANOVA and canonical correspondence analysis (CCA). The normalized differential vegetation index (NDVI) and canopy cover around all village types decreased with disturbance gradients, while the magnitude of change varied according to the type of settlement. Limited canopy cover was observed in refugee camps and new resettlements, compared to old resettlements and protected areas. Woody vegetation height class showed a J shaped distribution in all sites except refugee camps (RC), indicating a decline in vegetation. CCA showed that variables like site type, altitude and disturbance gradient significantly affected the diversity of woody species at the different sites. Comparison of individual species responses to disturbances indicated that low fodder value invaders like Dichrostachys cinerea, and many Acacia species were increasing in proportion and coverage at the expense of some multipurpose species including Tamarindus indica, Diospyros mespiliformis, and Pterocarpus lucens. In the absence of regulated vegetation use, resettlements result in a decline in overall vegetation cover and a shift in floristic diversity in favor of invasive species.     

近邻指数的城管案件全局分布模式分析

城市管理案件量化分析是城市管理水平提升的技术支撑。针对城市管理典型案件(街面秩序、市容环境及宣传广告),该文提出了一种热点探测流程和方法,并分析城市管理案件全局分布模式。针对传统量化研究的权重确定未考虑研究对象空间分布的问题,该文提出了基于城管案件近邻指数的权重确定方法,并以此为基础开展城管案件的全局分布模式研究。实验结果表明:3种典型城市管理案件呈显著的聚集分布,并且热点区域符合实验区的实证考察;近邻指数作为权重指标具有客观性、计算高效性,合理反映了城管案件的空间分布。     

FPSO结构低周疲劳寿命计算方法研究

FPSO在海洋环境中频繁地进行装载与卸载操作,使FPSO船体结构产生较大的应力幅值,尤其是承受货油压力的内底纵骨。由于局部的应力集中,应力幅值超过材料的屈服强度,其装卸载次数小于104时,结构将产生低周疲劳。研究一种新的计算方法,根据Neuber假设进行塑性修正,通过应变范围得到伪热点应力范围,并确定热点应力与伪热点应力之间的关系。推导出一种新的S-N曲线作为低周疲劳的设计曲线,以伪热点应力作为计算量来预测低周疲劳寿命,降低了船体结构低周疲劳寿命计算的难度。     

基于免棱镜全站仪的竖井高精度测量

为了解决竖井测量中地面设站仪器与井底不通视问题,文中不采用联系三角形测量将地面坐标和方位传递到井底,而进行自由设站测量,并通过联测基准点、坐标高程转换,实现地面、井底坐标与高程系统统一,操作简单快捷、精度高,为竖井测量提供一种新思路。利用免棱镜全站仪测量的竖井高精度数据,绘制竖井三维散点图,达到了良好效果。     

宁夏生态移民无土安置区风险评估研究

生态移民无土安置是指安置地不再为迁入的移民提供耕地,而是直接在城镇为其安排住房,将移民安插到企业务工或为移民提供就业平台,努力使移民通过在企业务工或自谋职业来满足其家庭生计。针对无土安置区资源、环境、经济、社会4个子系统在地理时空上的交织耦合结果,依据各个安置区区位、自然环境、经济发展水平、资源禀赋特色等关键性要素,在宁夏40个无土安置区中判别出6个"安置特征区",运用AHP模型对其进行风险评估,得出了安置区风险因子的风险程度及排序,为生态移民建设及无土安置区风险防范工作提供重要参考。