Half Smooth Tongue Sole(Cynoglossus semilaevis) Under Low Salinity Stress Can Change Hepatic igf2 Expression Through DNA Methylation

Salinity is a crucial environmental stress that severely affects fish growth and survival.Under environmental stress,DNA methylation plays an important role in gene expression and genome function.To better understand the epigenetic regulation mechanism of igf2 under low salinity stress,we analyzed the DNA methylation at 5’UTR,exon1,intron1,and exon2,and analyzed the relationship of DNA methylation with mRNA abundance as well as the special single CpG sites methylation patterns of igf2 in the liver of half smooth tongue sole under low salinity(15)for 0,7,and 60 d.When exposed to low salinity,DNA methylation at 5’UTR and exon2 remained stable,while it was up-regulated firstly and then down-regulated at exon1 and intron1.Some single CpG sites of igf2 associated with low salinity,and most of these sites with significantly changed methylation levels(P<0.05)are located in intron1 area.The discrepant variation of single CpG sites methylation levels and igf2 expression further revealed that females and males showed different response to low salinity.Remarkably,the 38-CpG site of intron1 servers as a sexual marker.Additionally,our integrative analysis demonstrated that regional DNA of igf2 methylation had highly complex interplay on gene expression.The single CpG sites in intron1 were indispensable epigenetic markers under external environmental stress.Above all,to resist the low salinity stress,half smooth tongue sole liver can regulate the expression of igf2 through methylation of CpG sites in intron1.     

Numerical Simulation for Refraction-Diffraction of Waves in Water of Slowly Varying Current and Topography

A new numerical finite difference iteration method for refraction-diffraction of waves in waterof slowly varying current and topography is developed in this paper.And corresponding theoretical modelincluding the dissipation term is briefly described,together with some analysis and comparison ofcomputational results of the model with measurements in a hydraulic scale model(Berkhoff et al.,1982).An example of practical use of the method is given,showing that the present model is useful to engineeringpractice.     

等高线的树结构模型

地形图综合中地貌综合是一大难题,只是以单根等高线的综合来实现地貌综合是不行的。为了等高线综合的方便,必须对等高线进行结构化处理,本文探讨了等高线的树结构建立。     

地图模糊矩阵模型与制图术语表述数学化研究

笔者在过去所研究地图模糊矩阵模型的基础上,进一步探讨了建立地图模糊矩阵模型问题,通过矩阵运算来对地图学中有关制图综合、图象变换等概念给出了数学定义,从而使概念表述数学化。     

基于地图数据库的复合目标的建立

地形图综合中为了体现景观特征,必须考虑到要素间的关系,特别是在地形图的自动综合中更是如此。本文在地图数据库的基础上,探讨了复合目标的建立问题。     

基于广义垂线坐标系的三维非结构数学模型及其在珠江口的应用

基于广义垂线坐标变换,构建了非结构网格的三维水动力数学模型。模型采用半隐式有限体积法对控制方程进行数值离散,其中半隐式法用于水位梯度和垂向紊动扩散以及垂向对流项的离散,显式控制体积分法用于水平对流项等的离散。广义垂线坐标系使得模型能够灵活地对垂向网格进行布置,平面非结构网格使得模型能够适应河口海岸复杂的岸线,并可对局部进行网格加密。模型通过具有解析解的风生流和异重流对模型进行检验,应用模型模拟了珠江口的三维潮流过程,计算结果与实测水文数据的比较表明,模型能够较好地模拟珠江河口的盐水楔和三维分层水动力过程。     

基于非差观测的网络实时动态定位方法及其在连续运行基准站跨网服务中的应用

基于非差观测的网络实时动态定位(RTK)方法通过提供每颗卫星的误差改正量,使网内用户获得与网络RTK方法等价的快速精密单点定位服务。当用户跨越连续运行基准站(CORS)网内由不同参考站组成的子网(参考子网)甚至跨越不同CORS网时,都能有效避免因所选取的主参考站变化而引起的模糊度重新初始化,从而保持观测时段内用户定位结果的连续可靠和跨CORS网服务时算法上的无缝衔接。通过对海上实测动态数据处理结果的分析,验证该方法的定位精度、初始化时间与现有网络RTK方法在量级上的一致性,以及跨不同参考子网和CORS网时实现无缝衔接的有效性。     

一种复杂海天背景下的红外舰船目标自动检测方法

提出了一种红外舰船目标检测算法。首先,利用设计好的频域组合高通滤波器对原始红外图像进行处理,以得到舰船目标可能存在的区域即目标潜在区;然后,对获得的目标潜在区进行尺度自适应的局部阈值分割,进而提取出较为完整的舰船目标或者虚假目标;最后通过检测吃水线特征来筛选出正确的舰船目标。实验结果表明,此算法能够有效地检测出复杂海天背景条件下的红外舰船目标,且具有一定的时效性。     

湖北巴东栖霞组缺氧沉积环境的地球化学特征

地层的岩石地球化学特征是判断其形成环境氧化还原条件的重要手段之一。对湖北巴东水布垭剖面栖霞组中层纹状灰岩和含泥质灰岩的地球化学分析,结合鄂湘桂地区栖霞期区域沉积古地理背景及栖霞组沉积学、古生态学特征,表明该区栖霞组沉积于一贫氧的沉积背景。同时该研究表明大部分适用于判别泥质岩古氧相的痕量元素和稀土元素地球化学比值,如U/Th、Ni/Co、V/(V+Ni)和Ce/La也可适用于该组以钙质沉积为主的沉积物。但部分指示,如V/Cr在碳酸盐岩中的应用值得今后研究注意。     

Optical Photometric Observations of 7-Ray Loud Blazars

We report results of our optical photometric observations of ten gamma-ray loud blazers, namely: 0219+428 (3C66A), PKS 0420-014 (OA 129), S5 0716+714, 0754+100 (OI 090.4), 0827+243 (OJ248), 1652+398 (Mrk 501), 2200+420 (BL Lacertae), 2230+114 (CTA 102), 2251+158 (3C 454.3) and 2344+514. The observations were carried out in September-October, 2000 using the 70 cm optical telescope at Abstumani Observatory, Georgia. We found intra-day variations in 0420-014, S5 0716+714, BL Lacertae and CTA 102. A variation of 0.3 magnitude over a time scale of about 3 hours was observed in the R passband in BL Lacertae on JD 2451827. We did not detect any variation in 3C 66A, Mrk 501, or 3C 454.3 during our observations. Nor did we detect any clear evidence of variation in 1ES 2344+514 during our two weeks' observing run of the TeV gamma-ray source.