Cloning of cytochrome P450 1A (CYP1A) genes from the hermaphrodite fish Rivulus marmoratus and the Japanese medaka Oryzias latipes

To use two small fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) and the Japanese medaka Oryzias latipes (Belloniformes) as testing models in molecular ecotoxicology, we have cloned the cytochrome P450 1A (CYP1A) gene after screening of both genomic DNA libraries, and sequenced 11,863 and 7,243 bp including all the exons and introns with promoter regions, respectively. The Rivulus and the medaka CYP1A gene consisted of seven exons (including non-coding exons) with high homology to mammals. In the promoter region, Rivulus CYP1A gene has seven xenobiotic response elements (XREs) and two metal response elements (MREs), while the Japanese medaka CYP1A gene has six XREs and four MREs. Interestingly, medaka CYP1A gene has a number of MREs at the promoter, which may affect its response on metal exposure. We describe here the gene structure of both fish CYP1A genes.     

Detection of DNA damage in mussels and sea urchins exposed to crude oil using comet assay

The single-cell microgel electrophoresis assay or the comet assay was used to evaluate DNA damage of dispersed crude oil on sea urchins (Strongylocentrotus droebachiensis) and mussels (Mytilus edulis L.). Sea urchins were exposed to 0.06 and 0.25 mg/L dispersed crude oil in a continuous flow system, while the mussels were exposed to 0.015, 0.06 and 0.25 mg/L dispersed crude oil. Sea urchin coelomocytes and mussel haemocytes were sampled after 4 and 5 weeks exposure, respectively. In the sea urchin coelomocytes, there was a significant concentration-related increase in the percentage of DNA in comet tail. In mussel haemocytes, there was a significantly higher percentage of DNA in comet tail for all treatments compared to the control. The responses were concentration-related up to 0.06 mg/L oil. The two highest exposure concentrations of mussels were not significantly different from each other. These results indicate that the comet assay can be used for biomonitoring of DNA damage in marine invertebrates following oil contamination.     

建筑物基础沉降数学模型研究

建筑物的基础沉降情况对建筑物的安全运营至关重要。已越来越受到人们的重视。本文在分析建筑物基础沉降成因的基础上，吸取当前常用数学模型的优点，经综合分析，事理成为一种全新的数学模型，并应用工程实测数据，对该数学模型的精度、预报能力等进行了验证，证明该模型是一种较有效的数学模型。     

改进PS提取方法在GB-InSAR中的应用

地基合成孔径雷达(GB-InSAR)可以实现对小范围目标的连续高精度监测,而永久散射体可以帮助GB-InSAR系统提供稳定可靠的监测目标。相关系数阈值法是一种传统的永久散射体提取方法,但在实际应用中存在一定的误选。为了减少误选,提高相关系数阈值法选取永久散射体的可靠性,提出一种改进的相关系数阈值法,并通过实验验证其可靠性。     

成层土的一维固结

采用３种方法来分析具有相同固结系数但却有不同压缩性和渗透性的双层土体的一维固结。通过对３种方法的对比分析得出,采用基于压缩系数ｍｖ和渗透系数ｋ来求解的方法比其它方法合理,因为该方法充分考虑了饱儿土体的固－液两相性。     

变权组合预测模型在大坝沉降监测中的应用

为探讨变权组合预测模型在变形监测中的应用,以监测某大坝沉降量为实例,研究基于线性回归预测模型和灰色模型GM(1,1)的变权组合。通过预测该大坝坝内沉降量,比较两种单一预测模型和变权组合预测模型的预测误差平方和,证明变权组合预测模型在沉降预测中具有更好的预测精度。     

基于小波分析的灰色-神经网络组合模型在大坝变形预测中的应用

监测序列经小波分解后可以得到各层分量。对低频分量采用灰色GM(1,1)模型进行建模预测,对高频分量采用BP神经网络进行建模预测,最后将各分量进行小波重构,得到监测序列的预测值。将预测值分别与没有进行小波分解直接用GM(1,1)模型预测的值和经小波分解的低、高频系数都采用GM(1,1)模型预测的值进行对比,发现经小波分解的灰色-神经网络组合模型预测精度更高。     

基于平面特征的地面雷达点云配准算法

针对地面LiDAR点云配准中不同坐标系点云数据存在对应的平面特征不同的问题,文章提出了一种基于总体最小二乘的地面LiDAR点云数据配准算法:通过对分割后的点云数据平面拟合,得到相应法向量;根据不同坐标系中LiDAR点云数据对应的平面法向量,利用反对称矩阵和罗德里格矩阵的性质,用3个独立参数代替3个旋转参数,采用总体最小二乘法建立旋转矩阵解算模型;采用总体最小二乘法确定平移参数的计算公式;最后根据转换后特征点云与对应平面点云的重复情况,给出了配准模型的精度公式。实验结果表明该方法精度较高,可以取得较好的点云配准效果,适合于含有大量重复平面特征的点云数据的配准。     

高铁无砟轨道基准点平面测量方法

介绍一种在狭长测量条件下基于边角后方交会自由设站的测量方法,阐述方法的原理,并结合石武高铁CRTSⅡ型板式无砟轨道基准点平面测量的具体实例应用,分析该测量方法的精度,证明该方法在狭长呈带状、要求越来越高的测量环境中应用的可行性和可靠性,对其他大型精密工程测量具有参考价值。     

南京长江第四大桥索夹的定位测量

以南京长江第四大桥索夹放样为例,介绍该桥索夹位置计算和测量放样的基本方法和流程。分析影响悬索桥索夹放样精度的因素,并加以修正或消除,用以提高索夹放样精度。实践证明本桥索夹放样方法简单、可靠,满足设计要求。