极坐标系有限差分中起伏地表边界条件处理

有限差分算法是地震学中重要的算法,在直角坐标系下同位网格有限差分中使用牵引力镜像方法,可以高效准确地处理起伏地表边界条件.当研究区域-全球尺度问题时需要考虑地球曲率影响,此时选择极坐标系更加直观方便,但已有方法无法在极坐标系下准确计算起伏地表影响.本文在极坐标系有限差分中引入贴体网格和牵引力镜像方法处理起伏地表边界条件...     

The phase difference effects on 3-D structure of wave pressure acting on a composite breakwater

In designing the coastal structures, the accurate estimation of the wave forces on them is of great importance. In this paper, the influences of the phase difference on wave pressure acting on a composite breakwater installed in the three-dimensional (3-D) wave field are studied numerically. We extend the earlier model [Hur, D.S., Mizutani, N., 2003. Coastal Engineering 47, 329–345] to simulate 3-D wave fields by introducing 3-D Navier–Stokes solver with the Smagorinsky's sub-grid scale (SGS) model. For the validation of the model, the wave field around a 3-D asymmetrical structure installed on a submerged breakwater, in which the complex wave deformations generate, is simulated, and the numerical solutions are compared to the experimental data reported by Hur, Mizutani, Kim [2004. Coastal Engineering (51, 407–420)]. The model is then adopted to investigate 3-D characteristics of wave pressure and force on a caisson of composite breakwater, and the numerical solutions were discussed with respect to the phase difference between harbor and seaward sides induced by the transmitted wave through the rubble mound or the diffraction. The numerical results reveal that wave forces acting on the composite breakwater are significantly different at each cross-section under influence of wave diffraction that is important parameter on 3-D wave interaction with coastal structures.     

Genetic diversity and differentiation of three populations of Penaeus monodon Fabricus

Genetic diversity of two wild Penaeus monodon populations sampled from the coastal waters of Qinglan （ Hainan Province of China, HN） and Malaysia （KD）, and the F1 generation of a Thailand broodstock population （CP） were examined by vertical polyacrylamide gel electrophoresis. Of 21 loci encoded by ten enzymes, 11 were polymorphic. The mean proportions of polymorphic loci of HN, KD and CP were 36. 36%, 45.45% and 50.00% , with the average heterozygosities of 0.135, 0.181 and 0.191, and the effective numbers of alleles per loci were 1. 300, 1. 330 and 1. 329, respectively. The divergent indexes of HN, KD and CP were0.023, 0.124, and 0.117, respectively. The genetic distance between the two wild populations was 0.005, and the gene differentiation coefficient was also very low （0.014）. The results indicated that the F1 generation population had a higher genetic diversity than the two wild populations, and that the HN population had the lowest one. There was no significant differentiation between HN and KD populations and all populations existed with a slight heterozygote excess.     

Simulation of nonlinear wave run-up with a high-order Boussinesq model

This paper considers the numerical simulation of nonlinear wave run-up within a highly accurate Boussinesq-type model. Moving wet–dry boundary algorithms based on so-called extrapolating boundary techniques are utilized, and a new variant of this approach is proposed in two horizontal dimensions. As validation, computed results involving the nonlinear run-up of periodic as well as transient waves on a sloping beach are considered in a single horizontal dimension, demonstrating excellent agreement with analytical solutions for both the free surface and horizontal velocity. In two horizontal dimensions cases involving long wave resonance in a parabolic basin, solitary wave evolution in a triangular channel, and solitary wave run-up on a circular conical island are considered. In each case the computed results compare well against available analytical solutions or experimental measurements. The ability to accurately simulate a moving wet–dry boundary is of considerable practical importance within coastal engineering, and the extension described in this work significantly improves the nearshore versatility of the present high-order Boussinesq approach.     

帘蛤科4种养殖蛤群体遗传多样性和种间关系的fAFLP分析

利用荧光标记扩增片段长度多态性(fAFLP)技术对文蛤(Meretrix meretrix)、青蛤(Cyclina sinensis)、菲律宾蛤仔(Ruditapes philippinarum)和硬壳蛤(Mercenaria mercenaria)4种帘蛤科贝类的群体遗传多样性和种间关系进行了研究。选择EcoRⅠ/MseⅠ进行酶切,使用6个E 3/M 3引物组合进行扩增,共获得1 096个位点,多态位点比率95.1%,片段长度50~456 bp。其中,文蛤、青蛤、菲律宾蛤仔和硬壳蛤分别得到681,715,702和694个位点,相应的多态位点比率为76.8%,81.7%,83.0%和75.1%,得到17个种特异性位点,可作为4物种特征标记。分析了群体遗传相似系数和遗传多样性指数以及种间遗传相似系数。结果表明,硬壳蛤群体遗传相似系数最高(0.670 9),遗传多样性指数最低(0.236 0);菲律宾蛤仔群体遗传相似系数最低(0.592 5),遗传多样性指数最高(0.261 8);根据遗传相似系数采用UPGMA法构建了4物种32个体的聚类图,表明文蛤与菲律宾蛤仔遗传关系最近,青蛤与其他3物种遗传关系较远。     

长江下游鳊鱼遗传多样性的RAPD分析

应用RAPD技术对长江下游鳊鱼群体的遗传多样性进行分析,从40个随机引物中筛选出28个引物对鳊鱼24个个体的基因组DNA进行扩增,共检测到178个位点,分子片段在0.2～2.0kb之间,其中多态位点83个,占46.63%;个体间最大的遗传距离为0.1326,最小的遗传距离为0.0476,平均遗传距离为0.0885;群体的Nei基因多样性指数为0.2593,Shannon多样性指值为0.0986。与其他鱼类的遗传多样性研究结果相比,长江下游鳊鱼群体的遗传多样性处于中等水平。     

皱纹盘鲍野生与养殖群体微卫星标记遗传变异研究

采用7个微卫星标记对辽宁大连、山东烟台、荣城、崂山和胶南5个皱纹盘鲍养殖群体,以及山东长岛、荣城、日本岩手、韩国仁川4个皱纹盘鲍野生群体进行了群体遗传多样性与遗传分化的研究.结果表明,从等位基因数与杂合度上分析,养殖群体(N=8.0～9.4,He=0.754～0.787)遗传多样性显著低于野生群体(N=11.3～15.0,He=0.821～0.866);等位基因频率分布揭示出野生群体中一些稀有等位基因在养殖群体中有所丢失;亲鲍选用数量少与性别比例不均衡可能是产生养殖群体中遗传多样性显著减少的原因.通过对等位基因频率比较分析,5个养殖群体之间以及养殖群体与野生群体之间观察到显著差异的Fst与Rst值,野生群体之间日本群体Fst与Rst值与其他3个野生群体差异显著,群体间存在遗传分化;养殖群体间遗传距离与地理距离不相关,可能是皱纹盘鲍育苗过程中亲鲍和苗种频繁交流所造成的结果;日本群体与其他3个野生群体间存在显著遗传分化与皱纹盘鲍短暂的浮游期与有限的扩散能力有关.     

牙鲆GHR基因Promoter区微卫星序列多态性与生长性状关系的初步研究

采用牙鲆GHR基因5'端Promoter区的1个微卫星标记,对胶南和日照2个牙鲆养殖群体进行了群体遗传多样性的研究,并探索该基因多态性位点与牙鲆生长性状之间的相关性.结果表明,2个群体在该座位的等位基因数为12和9个,有效等位基因数为6.26和5.04个,多态信息含量为0.84和0.80.2个群体该座位的Hardy-Weinberg遗传偏离指数均为正值,并没有显示出杂合子缺失,但各基因型分布频率都在一定程度上偏离Hardy-Weinberg平衡(P<0.01).连锁分析中发现,在胶南群体中,IM基因型对应的个体在全重、全长、体长、头长、体高和眼径形态学数据中均是最大的;在日照群体中,BC基因型对应的个体在全重、全长、体高、尾柄高、尾柄长和眼径数据中均是最大的;而CJ基因型对应的个体在体长和头长这两组数据中是最大的.该结果为研究GHR基因的变异对鱼类生长发育的影响及探索将该基因作为生长遗传标记的可行性奠定了实验基础.     

Genetic diversity analysis with ISSR PCR on green algae Chlorella vulgaris and Chlorella pyrenoidosa

In the present study, genetic polymorphism and diversity in unicellular clones of Chlorella vulgaris Beijerinck and Chlorella pyrenoidosa Chick were studied with Inter Simple Sequence Repeats PCR (ISSR PCR). Samples including four clones of C. vulgaris and three clones of C. pyrenoidosa were purified by single-clone-choice method. For four C. vulgaris unicellular clones, the total number of the bands scored for 18 primers was 298; and the number of the polymorphic bands was 118, of which 39.6% were polymorphic. The size of PCR products ranged from 200 to 2 500 bp. The total number of bands scored for 18 primers, the number of polymorphic bands and the percentage of three C. pyrenoidosa unicellular clones was 194.83 and 30.8%, respectively. POPGENE analysis show that the average Nei genetic diversity (h *) and Shannon index of diversity (I *) in the four C. vulgaris unicellular clones was 0.2181 and 0.3208, respectively, which is slightly higher than those of the three C. pyrenoidosa unicellular clones (0.190 3 and 0.274 8), which agreed with the percentage of polymorphic bands in the mixed samples of the two species. The results suggest that ISSR is a useful method to Chlorella for intra-species genetic analysis.