Comparison of growth and survival of larvae among different shell color stocks of bay scallop Argopecten irradians irradians（Lamarck 1819）

In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%,91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%,respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.     

Comparison of growth and survival of larvae among different shell color stocks of bay scallop Argopecten irradians irradians (Lamarck 1819)

In order to improve production and breed new broods of bay scallopArgopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis. This work was financially supported by Project of Scientific Innovation, Chinese Academy of Sciences (ZKCX2-211).     

The properties of the dust shell of BN Object

In this paper we make a theoretical analysis of multi-wavelength photometric data on the infrared continuum of BN Object. Adopting a spherically symmetric, optically thin shell model we derive its optical thickness, its infrared emissivity as a function of wavelength, its radial distributions of density and temperature and its total mass.     

Kinematics of the Gum nebula region

To investigate the kinematics of the neutral material around the Gum nebula, emission from hydroxyl at 1667 MHz was observed at many positions over the region. Fitting models of expanding shells to these data together with previously published molecular line data shows that the diffuse molecular clouds and cometary globules form a single expanding shell centred on G261−2.5. The mean angular radius is 10.5° and its maximum radius is 14°. The models show that the distance range to the expansion centre is from 200 pc to 500 pc.
The path of the runaway O-star ζ Puppis passed within <0.5° of the expansion centre of the neutral shell ∼1.5 Myr ago. The supernova of the erstwhile binary companion of ζ Puppis is the probable origin of the Gum nebula and the swept up expanding neutral shell. The 500-pc distance to the supernova is adopted as the distance to the expansion centre of the neutral shell. At this distance the energy required to produce the observed expansion could have been met with a single supernova. The radii of the front and back faces of the shell are 130 and 70 pc respectively. The front face is expanding faster than the back face, at 14 and 8.5 km s⁻¹ respectively.
The extent of the neutral shell matches the radio continuum and H α emission of the Gum nebula well. The photoionized gas in the nebula is probably primarily ionized by ζ Puppis, which is still within the neutral shell. No evidence was found for the IRAS -Vela shell as a separate expanding shell.     

墨西哥湾扇贝稚贝盐度适应性的研究

在室内控制条件下,观察不同海水盐度对墨西哥湾扇贝(Argopecten irradians concentricusSay)稚贝存活及生长的影响,并将168 h 50%死亡的盐度作为适宜生存临界盐度,将增长率为最佳增长率30%时所对应的盐度作为适宜生长临界盐度。结果表明:在稚贝壳高4.38 mm±0.31 mm,水温25.4~27.8℃,pH值7.8~8.2下,墨西哥湾扇贝稚贝适宜生存盐度为23.6~35.7,最适生存盐度为26.0~31.3;适宜生长盐度为23.9~35.8,最适生长盐度为28.7~31.3。在盐度变化超出最适范围时,`墨西哥湾扇贝稚贝对低盐更为敏感,高盐比低盐对稚贝存活、生长、增重的影响小。当盐度为28.7时,墨西哥湾扇贝稚贝具有最高的相对存活率(100%)、壳高日增长率(0.116 2 mm.d-1)及体重日增长率(1.95 mg.d-1)。当盐度在最适范围之外升高或降低,稚贝的存活率、壳高及体重日增长率也随着降低。     

巴颜喀拉块体强震动力学过程数值模拟

以青藏高原为目标采用弹性体本构关系,模拟印度板块持续向北推进、挤压对巴颜喀拉块体及邻区的影响.通过降低强震发生位置处单元弹性模量的方法,模拟1900年以来发生在巴颜喀拉块体及周缘Ms≥7.0强震,计算序列中前面地震对后续强震的影响.模拟结果表明:①巴颜喀拉块体背景场应力水平大致与块体西部等效应力同等大小,自西向东逐渐递减,巴颜喀拉块体西部和中部等效应力从南向北逐渐递减,东部地区等效应力比较低;②模拟的14次地震序列中,有8次发生在前面强震所引起的等效应力增大的区域内,2次发生在等效应力增大和减小的过渡区域内,3次发生在等效应力减小的区域内;③从强震序列所引起的应力相互作用看,历史地震对1970年以来发生的地震影响结果为:历史地震加速了1973年亦基台错、1997年玛尼和2001年昆仑山口西地震的发生,昆仑山口西地震对汶川地震的影响较小,汶川地震对玉树地震的发生不具有加速触发作用.     

基于等高线的三角网快速构建与处理

采用一种利用等高线数据,快速处理和优化TIN的方法。该方法首先将等高线离散成数据点集;然后利用凸壳技术快速地进行三角形构网;再利用TIN的拓扑结构快速内插入等高线,形成约束TIN;最后利用三角形与特征边的关系及TIN的拓扑结构,从而快速消除平坦三角形,提高TIN的质量。     

Linux Shell在卫星定轨软件中的应用

Linux系统由于其开放性、安全性和稳定性受到众多机构和科研单位的认可,许多知名的卫星导航定位软件都是基于Linux系统开发。Shell脚本语言是Linux系统上一种重要的脚本语言,熟练地使用Shell语言可以解决或简化许多问题。本文总结了Shell语言在卫星定轨软件中的一些应用,包括数据下载、数据合并、数据传输、自动化运行与错误预警等,可以为从事卫星导航定位领域的科研人员或工作人员提供参考。     

对虾壳色素提取及部分性质研究

以水产加工废弃物 (对虾壳 )为原料 ,经过对对虾壳的烘干、碾碎、提取、洗涤和分离 ,提取了对虾壳色素。探讨了该虾壳色素的部分性质 ,得到如下初步结论 :在可见光区对虾壳色素的 λmax为 470 nm,在 1 0 0℃加热时间不超过 1 5 min的条件下对虾壳色素对热较稳定 ,耐氧化 ,光照影响对虾壳色素的稳定性。     

New stratigraphic markers in the late Pleistocene Palouse loess: novel fossil gastropods, absolute age constraints and non-aeolian facies

Four stratigraphic sections in the southern part of the Columbia Basin preserve a sequence of aeolian and non-aeolian sediments ranging in age from 9·43 to >47·0 ¹⁴C ka based on accelerator mass spectrometry radiocarbon dating of fossil molluscs, geochemistry of Cascade Mountain-sourced tephra and association with formally recognized pedostratigraphic units (the Washtucna and Old Maid Coulee soils). Study sections are interpreted as representing concurrent deposition of loess and distal Missoula Flood rhythmites in valleys tributary to main drainages backflooded during the Missoula Floods, and formation of carbonate and iron-rich soils. Sediments belong to the formally recognized L-1 and L-2 loess units established for the Palouse loess, which were deposited in the Columbia Basin subsequent to events of glacial outburst flooding. Sediments associated with the Mount Saint Helens set S and set C tephras in the study sections preserve a fauna of five species of gastropod mollusc which have not been reported previously from sediments of late Pleistocene age in the Palouse region. The fossils comprise two distinct faunules stratigraphically separated by the Mount Saint Helens So tephra. Accelerator mass spectrometry radiocarbon dating of the fossils collected above the tephra in two of the sections yielded ages of 12·48 ± 0·06 and 9·43 ± 0·05 ¹⁴C kyr. These ages suggest that independent determinations of the 13·35 ¹⁴C kyr age of the So tephra in other areas where Missoula Flood sediments are preserved are probably accurate, and help to refine the age of the latest events in the most recent sequence of catastrophic glacial outburst flooding.