AFLP analysis revealed differences in genetic diversity of four natural populations of Manila clam(Ruditapes philippinarum) in China

1 IntroductionManila clam (Ruditapes philippinarum) is aworldwide distributed species. In China, it is foundfrom the northern to southern seashores (Wang etal., 1993; Zhuang, 2001). This species is eura-line with the salinity tolerance ranging from 20 to4…     

Shipborne GPS attitude determination during MMST-93

The attitude parameters of a ship underway were measured using a configuration of four 10-channel NovAtel Model 951 narrow-correlator-spacing receivers. These C/A code receivers have output rates of up to 10 Hz and maintain effective carrier phase lock under relatively harsh ship dynamics. The attitude parameters are calculated independently at each epoch using differential carrier phase measurements, carrier phase ambiguities are resolved on-the-fly by constraining the approximately known distances between the antennas that are rigidly mounted on the ship. Carrier phase thermal noise and multipath are minimized by mounting the antennas as far apart as possible. The four-antenna configuration provides redundancy and further improves accuracy. During the Matthew Motion Sensor Trials (MMST-93) conducted off the coast of Halifax, Nova Scotia, in June-July 1993, the GPS-derived attitude parameters were compared with those obtained with a Honeywell HG1050 ring laser gyro inertial navigation system (INS) which provides roll and pitch with an accuracy of 15 arcsecs and heading with an accuracy of 2 arcmins. To simulate rough weather conditions, sharp maneuvers were performed to induce roll angles in excess of 10°. No accuracy degradation nor any loss of GPS measurements occurred. The RMS agreement between GPS and INS derived attitude parameters is better than 2 arcmins in heading, 1 arcmin in pitch and 3 arcmins in roll. This level of accuracy demonstrates the capability of GPS for cost-effective shipborne attitude determination at an accuracy level of 0.05     

高时空分辨率三维风场在强对流天气临近预报中的融合应用研究

以业务应用为目标,开展高时、空分辨率三维风场在强对流天气临近预报中的融合应用研究。运用北京快速更新多尺度分析和预报系统集成子系统（RMAPS-IN,Rapid-refresh Multi-scale Analysis and Prediction System-Integration）,对雷达四维变分分析系统（VDRAS）30 min临近预报的高时、空分辨率三维风场作为数据源与自动气象站风场观测进行快速融合处理。结果表明,以VDRAS临近预报风场取代数值模式预报场作为融合初猜场后形成的分析结果对于风场有明显的改善:（1）长时间序列客观检验结果表明,地面10 m高风场U/V分量绝对误差分别为0.05和0.06 m/s。实时融合对未来预报的影响随着预报时效的延长,U/V分量的绝对误差不断增大。（2）对于11个强对流个例,地面10 m高风场风速均方根误差降低0.3 m/s,风向均方根误差降低13°;边界层三维风场,风速均方根误差降低0.8 m/s,风向均方根误差降低10°。平原站点融合以后风速、风向预报效果有较大改善,山区站点融合以后改善相对较小。（3）通过对2017年7月20日暴雨和7月7日雷暴大风个例的详细分析,发现融合基于雷达资料四维变分同化获得的高分辨率临近预报风场对各对流系统中的中尺度结构特征给出了更加细致准确的描述。      

APPLICATION OF THE MULTIGRID METHOD IN NUMERICAL SIMULATION OF SEDIMENT TRANSPORT

IINTRODUCTIONThemultigridmethod(Brandt,1988)iswidelyusedinmanydisciplinesandengineeringsubjects,especiallyintheareaofComputationalFluidMechanicsbecauseofitshighefficiencyincomputation.Themultigridmethodhasbeenprovenintheorytobeoneofbestnumericalmethodsforsolvinglinearellipticproblemsbecausetheloadofcomplltationisindirectproportiontothenumberofgridnodes;theconvergentspeedofmultigridmethodisirrelevanttothesizeofgird.Soitissuitableforthenumericalsimulationoffullscaleengineeringprojects.The…     

1961-2010年辽宁省高温日数和高温热浪特征分析

利用1961-2010年辽宁省52个气象站日最高气温资料,分析辽宁地区高温日数及热浪的分布特征和变化趋势,结果表明：辽宁省区域年平均高温日数为7.72 d/ a。辽宁高温日数呈东少西多的空间分布,沿海地区较少甚至部分地区无高温情况出现。高温日出现最多的朝阳站,为26.48 d/ a。从20世纪60年代开始,高温日数呈缓慢增加趋势,其中2000年为有气象记录以来高温日最多的年份。热浪也呈东少西多的分布特征,热浪最多的朝阳站发生频次为2.90次/ a。辽宁省以持续3-5 d的轻度热浪为主,占86.27 %,中度热浪占12.58 %,超过10 d的重度热浪占1.14 %,仅有喀左、北票和羊山地区发生过持续10 d以上的重度热浪。     

Ecological quality assessment of small estuaries from the Portuguese coast based on benthic macroinvertebrate assemblages indices

Benthic macroinvertebrates communities are the most consistently emphasized biotic component of aquatic ecosystems and are one of the biological indicators required for assessment by the European Water Framework Directive. In this context, several indices based on these communities have been developed in order to assess ecological quality of estuarine systems. In the present work we used AMBI, M-AMBI, BENTIX and BAT to distinguish ecological status of five small estuarine systems of the Portuguese south and southwest coasts. Although indices outputs did not differ between systems and sampling seasons, results indicated that the metrics in which these indices are based could differentiate community structures as a result of two main gradients that force these communities: the natural variability, and the anthropogenic impact.     

安徽省巢湖地区二叠纪栖霞组、孤峰组硅质岩地球化学特征对比及大地构造背景分析

为探讨下扬子地区二叠系硅质岩的硅质来源和形成背景,以巢湖地区二叠纪栖霞组和孤峰组硅质岩为研究对象,收集了前人大量有关栖霞组和孤峰组的研究成果和数据,并对采自栖霞组和孤峰组硅质岩样品进行了主量元素、微量元素、稀土元素测试。栖霞组、孤峰组硅质岩样品测试结果显示,硅质岩的稀土元素经北美页岩标准化后的配分曲线近似平坦型向左倾斜,有弱Ce负异常,且HREE弱富集,反映了热水沉积硅质岩的特征。研究区硅质岩样品的Al Fe Mn三角图中,样品投点分布较广,即Al比值变化范围较大,认为是岩浆在喷发过程中受硅-铝质陆壳混染作用的结果。结合沉积环境判别指标分析认为：栖霞组硅质岩沉积时期其沉积环境主要为大陆边缘环境;孤峰组硅质岩沉积时期其沉积环境为大陆边缘-海盆过渡环境。从栖霞组到孤峰组沉积时期,海侵规模不断变大,水体变深,海盆面积扩大,研究区在不同时期沉积环境存在差异。研究区栖霞组、孤峰组硅质岩的沉积与大陆边缘裂陷活动紧密相关。     

自动气象站的网络化构想

本文是针对气象服务社会的这个宗旨,在自动气象站正式运行之后,应用路由器、交换机、微机ADSL宽带网络等通信设备和通信方式,对气象数据进行网络化管理和使用,提高气象信息的使用率。     

南极企鹅粪土沉积柱样、蛋卵中OCPs、PCBs含量分布及其环境意义

对南极阿德雷岛企鹅栖息地粪土层进行210Pb测年,同时采用气相色谱-电子捕获检测器(GC-ECD)内标定量法测定了企鹅栖息地粪土混合地层和企鹅蛋卵中有机氯污染物含量,粪土混合地层中有机氯污染物最高浓度:表层PCBs为0.92ng/g,HCHs为0.42ng/g,DDTs在0.70ng/g,与非栖息地相比较,研究结果显示,通过鸟类活动的粪土混合地层(营巢和粪便)输入PCBs和OCPs含量比无鸟类生命途径的土壤相对要高。企鹅蛋卵样∑PCB在0.4-10.2ng/g,∑DDT2.4-10.3ng/g,HCB0.1-9.4ng/g,∑HCH0.1-0.5ng/g,总积蓄水平依次为:∑PCB>∑DDT>HCB>∑HCH。     

关于露天矿山边坡稳定性管理研究的若干问题讨论

本文从科学管理的角度,讨论了露天矿山边坡稳定性管理研究的目的意义;详细论述了边坡稳定性管理研究的基本内容;并探讨了边坡岩体滑坡预报和治理加固时机问题,对保证露天矿山的安全生产具有现实意义。