Development of three multiplex PCR primer sets for ark shell (<Emphasis Type="Italic">Scapharca broughtonii</Emphasis>) and their validation in parentage assignment

Scapharca broughtonii is a commercially important and over-exploited species. In order to investigate its genetic diversity and population structure, 43 novel polymorphic microsatellites were isolated and characterized. The number of alleles per locus ranged from 3 to 22 with an average of 6.93, and the observed and expected heterozygosities varied between 0.233 and 1.000, and 0.250 and 0.953, with an average of 0.614 and 0.707, respectively. Three highly informative multiplex PCRs were developed from nine of those microsatellites for S. broughtonii. We evaluated and validated these multiplex PCRs in 8 full-sib families. The average polymorphism information content (PIC) was 0.539. The frequency of null alleles was estimated as 3.13% of all the alleles segregation based on a within-family analysis of Mendelian segregation patterns. Parentage analysis of real offspring demonstrated that 100% of all offspring were unambiguously allocated to a pair of parents based on 3 multiplex sets. Those 43 microsatellite loci with high variability will be helpful for the analysis of population genetics and conservation of wild stock of S. broughtonii. The 3 sets of multiplex PCRs could be an important tool of pedigree reconstruction, population genetic analysis and brood stock management.     

Numerical study on inter-tidal transports in coastal seas

Inter-tidal(subtidal) transport processes in coastal sea depend on the residual motion, turbulent dispersion and relevant sources/sinks. In Feng et al.(2008), an updated Lagrangian inter-tidal transport equation, as well as new concept of Lagrangian in- ter-tidal concentration(LIC), has been proposed for a general nonlinear shallow water system. In the present study, the LIC is nu- merically applied for the first time to passive tracers in idealized settings and salinity in the Bohai Sea, China. Circulation and tracer motion in the three idealized model seas with different topography or coastline, termed as ‘flat-bottom', ‘stairs' and ‘cape' case, re- spectively, are simulated. The dependence of the LIC on initial tidal phase suggests that the nonlinearities in the stairs and cape cases are stronger than that in the flat-bottom case. Therefore, the ‘flat-bottom' case still meets the convectively weakly nonlinear condi- tion. For the Bohai Sea, the simulation results show that most parts of it still meet the weakly nonlinear condition. However, the de- pendence of the LIS(Lagrangian inter-tidal salinity) on initial tidal phase is significant around the southern headland of the Liaodong Peninsula and near the mouth of the Yellow River. The nonlinearity in the former region is mainly related to the complicated coast- lines, and that in the latter region is due to the presence of the estuarine salinity front.     

Effect of bioactive peptides (BPs) on the development of Pacific white shrimp (<Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> Boone, 1931)

The present study was conducted to evaluate the feasibility of replacing fish meal (FM) with bioactive peptides (BPs) in diet of white shrimp (Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0% (control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate (WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con (P < 0.05), while no significant difference was found on survival rate and feed conversion ratio (FCR); 2) the whole-body crude protein (CP) and crude lipids (CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), phenol oxidase (PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in pH and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.     

Growth performance of larval and juvenile manila clam (<Emphasis Type="Italic">Ruditapes philippinarum</Emphasis>) from divergently selected individuals of a full-sib family

In this study, the method of divergent selection was employed to test the larval and juvenile growth performance within a full-sib family of Manila clam Ruditapes philippinarum. The 10% largest and 10% smallest clam individuals (on the basis of shell length) of a full-sib family were selected as parents for the fast and slow growing lines, respectively. The difference in shell length was significant among the three lines (fast, control, and slow) tested. The sequence of shell length were fast line > control line > slow line. The responses to selection, realized heritability, and genetic gain were 0.06%–0.81%, 0.04%–0.47% and 0.58%–18.89% in the fast direction, respectively; and were 0.14%–1.27%, 0.08%–0.73%, and 0.31%–49.03% in the slow direction, respectively. The results suggested that there was a large portion of additive genetic variance affecting the growth in the full-sib family. Selection in the fast direction within the full-sib family would greatly improve the growth of R. philippinarum.     

Phase characteristic analysis of continuous depth air-gun source wavelet

Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China.     

Temporal and spatial variations in extreme temperatures in the Qilian Mountains-Hexi Corridor over the period 1960-2013

Based on daily maximum and minimum temperatures at 18 meteorological stations in the Qilian Mountains and Hexi Corridor between 1960 and 2013, temporal and spatial variations in extreme temperatures were analysed using linear trends, ten-point moving averages and the Mann-Kendall test. The results are as follows: The trends in the majority of the extreme temperature indices were statistically significant, and the changes in the extreme temperatures were more obvious than the changes in the extreme values. The trends were different for each season, and the changes in rates and intensities in summer and autumn were larger than those in spring and winter. Unlike the cold indices, the magnitudes and trends of the changes in the warm indices were larger and more significant in the Hexi Corridor than in the Qilian Mountains. Abrupt changes were detected in the majority of the extreme temperature indices, and the extreme cold indices usually occurred earlier than the changes in the extreme warm indices. The abrupt changes in the extreme temperatures in winter were the earliest among the four seasons, indicating that these temperature changes were the most sensitive to global climate change. The timing of the abrupt changes in certain indices was consistent throughout the study area, but the changes in the cold indices in the Hexi Corridor occurred approximately four years before those in the Qilian Mountains. Similarly, the changes in the warm indices in the western Hexi Corridor preceded those of the other regions.     

Loss of preferred habitat and pollen limitation threatens reproduction in a rare mountain <Emphasis Type="Italic">Paeonia delavayi</Emphasis>

Paeonia delavayi is a wild tree peony species endemic to high-altitude regions in southwestern China. Recent agricultural land expansion, however, not only causes its dwindling population size, but also poses a severe threat to its long-term persistence. Since our knowledge of the reproductive biology of P. delavayi is very limited, and some management misconceptions have further exacerbated the already worrisome situation, the aim of the present study is to provide some scientific evidence regarding habitat preference and breeding system of P. delavayi, and to help correct some management misconceptions. Specifically, morphological traits of P. delavayi populations growing in two different habitats (i.e., the open area versus forest understory), including basal stem diameter, plant height and flower numbers per plant, were measured and compared with each other. A range of floral manipulation experiments was further conducted to study the extent of self-compatibility and pollen limitation. The results showed that P. delavayi preferred the open habitat over forest understory as it generally grew bigger with thicker stems, and produced a higher number of flowers in the former habitat. Therefore, the open habitat should receive immediate priority for conservation action instead of being converted to agricultural land; also, P. delavayi is pollen limited, as evidenced by the fact that experimental flowers receiving supplemental non-self pollen generally displayed elevated seed production than flowers subjected to other treatments (e.g., non-supplemental self pollen, non-supplemental non-self pollen and supplemental self pollen), which is consistent with reported observations that alpine plants are more likely to be pollen-limited than lowland plants. We suggest that human intervention might be necessary to guarantee the long-term persistence of P. delavayi as harsh alpine environment, intense competition for pollinators and different anthropogenic perturbations co-limit its reproductive success.     

Observed characteristics of atmospheric ducts over the South China Sea in autumn

The observed characteristics of lower atmospheric ducts over the South China Sea(SCS) were analyzed based on Global Position Systerm(GPS) radiosonde data collected four times daily during autumn open cruises from 2006 to 2012.Duct occurrence,thickness,and strength over the SCS were about 40%,150-m thick,and 8 M units,respectively,which were larger than during the summer monsoon period.Most ducts occurred at heights 1 500 m and these ducts easily trap electromagnetic wave clusters with wavelengths 2 m.Diurnal variation of the SCS ducts appeared evident.They occurred more often at midnight at higher altitudes(about 1 100 m),with a thickest layer of about 145 m and less frequently during the evening at lower altitudes(about 800 m),with a thinnest layer of about 125 m.Moreover,ducts during the daytime at a mean height of about 900 m,with the greatest strength of about 10 M units.Furthermore,all duct variables observed over the SCS in autumn decreased from north to south.These findings are useful not only in the design of radar and communication systems,but also for evaluating possible effects of anomalous propagation on meteorological radar and military applications.     

沂沭断裂带深反射地震资料处理

地震时间剖面可以对地质目标进行精细刻画,但由于变质岩、侵入岩地区存在地质体不规则、地质界线间波阻抗差异不明显、断裂构造倾角高陡等特征,导致地震原始资料具有波场复杂、干扰波发育、资料信噪比低等特点.为获得客观反应实际地质情况的沂沭断裂带深反射地震剖面,通过对研究区原始地震资料细致分析,针对各种干扰波的不同特性特征,分别采...     

面向不同用户群体的社交媒体台风舆情演化分析及对比研究

社交媒体数据可以为台风灾害追踪、灾时救援和灾情评估提供及时有效的信息。现有研究常采用主题建模和情感分析等技术对台风期间社交媒体平台（如新浪微博等）舆论话题和情感变化进行研究。在省域范围内以小时为时间粒度的多维度有效性论证尚有欠缺,且在舆情分析时未能区分用户群体差异。本文以台风“利奇马”为例,在浙江省域范围内,以新浪微博数据为研究对象,首先从词频分析、台风关注度时空变化以及特定灾害事件响应3个角度探讨了微博数据对台风灾情响应的有效性;其次采用隐含狄利克雷分布（Latent Dirichlet Allocation,LDA）主题模型技术挖掘微博文本主题信息,并根据Louvain算法对主题社团进行划分;然后开发了一种基于自定义情感词典的情感分析方法用于情感指数计算,与SnowNLP相比情感倾向性预测精度得到了提高;最后分析了台风期间官方和民众在新浪微博平台上的话题关注以及情感演变差异。结果表明：① 在省级范围内,微博数据能有效反映台风动态和灾害时空分布;② 台风事件微博文本的主题变化反映了灾情不同阶段舆论关注点的动态变化;③ 官方微博文本比民众微博文本具有更明确的主题社团结构;④ 台风事件相关微博文本中的消极情绪在台风登陆后显著增加,其中民众微博文本对台风灾害的情绪响应更及时,官方微博文本中的情感表达始终相对积极。