Temperature-control-induced masculinization in tiger puffer Takifugu rubripes

This study used tiger puffer Takifugu rubripes to explore new, simple methods for lowtemperature-induced masculinization in a cultured fish without the use of ultraviolet irradiation or sex hormones. An orthogonal test L_9(3~4) design was used to consider three factors at three levels: treatment starting times(days post-hatch, dph: factor A) of 20, 50 and 80 dph; treatment temperatures(factor B)of 13℃, 15℃ and 17℃; and treatment durations(factor C) of 30, 45 and 60 days. A control group was reared at 21±1℃. The experiments were repeated twice. At 230 dph, the gonads were removed from thirty randomly sampled fish in each group. Histological observations and analysis of single nucleotide polymorphisms(SNP) were used to identified pseudo males, which biological sex was male and genetic sex were female(XX). Treatment group 4(A2B1C2) resulted in the highest proportion of males(75%).According to the intuitive analysis of the orthogonal-array experiments, the optimal combination of lowtemperature-induced masculinization of T. rubripes was A2B1C2. The population sex ratio depended on the three factors in the sequence B→A→C. A comparison of the daily increases in length and weight during and after the low-temperature conditions showed that the absolute daily increases in weight and length were significantly less during treatment than after treatment. Daily increases in weight and length did not significantly differ between the treatment groups and the controls(P0.05), demonstrating that the growth rate could return to normal after the low-temperature conditions. This study establishes a low-temperatureinduced masculinization technology for T. rubripes and demonstrates that although the growth rate(length and weight) decreased in an array of nine treatment groups during the processing time, it returned to a normal level after processing. The results should serve as a guide for achieving the masculinization of T.rubripes in production.     

DBSCAN Clustering Algorithm for the Detection of Nearby Open Clusters Based on Gaia-DR2two

In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on the Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the Sun) from the Gaia-DR2 catalog, and construct a five-dimensional phase space (three-dimensional spatial position and two-dimensional proper motion) in order to obtain reliable cluster members. At the data preprocessing stage, we normalize each dimension of data to the [0, 1] interval in order to avoid the effect of inconsistent units. Then, we use the k-dist graphs to determine the input parameters of the DBSCAN Algorithm. Finally, we obtain 133 reliable members using the DBSCAN algorithm, which correspond to two open clusters—Hyades and Coma. According to these cluster members, the distances to the Hyades and Coma clusters are determined to be (6.5 ± 0.3) pc and (4.9 ± 0.4) pc, respectively.     

Numerical Investigation on Dynamics of the Tendon System of A TLP by Applying Absolute Nodal Coordinate Formulation

In the present study, the dynamics of the tendon system of a tension-leg platform(TLP) is investigated through the absolute nodal coordinate formulation(ANCF). Based on the energy conversion principle, the stiffness, generalized elastic force, external load and mass matrices of the element are deduced to perform the element assembling by using the finite element method. Then the motion equation of the tendon/riser is established. In this study, the TLP in the International Ship Structures Committee(ISSC) model under the first and second wave forces is considered as the case study. The simulation is performed in the MATLAB environment. Moreover, the accuracy and reliability of the programs are verified for cases of beam model with theoretical solutions. It is found that the motion response of tendons is affected by the TLP movement and environmental load, simultaneously. Then, the motion response is calculated using the SESAM software and exported as the boundary of ANCF tendons. Finally, the static and dynamic characteristics of the four tendons of ISSC TLP are analyzed systematically by the ANCF method.Performed analysis proves the effectiveness and feasibility of the ANCF method. It is concluded that the proposed method is a powerful scheme for calculating the dynamics of tendon/riser in the field of ocean engineering.     

Immune response of <Emphasis Type="Italic">Pseudosciaena crocea</Emphasis> to the injection of <Emphasis Type="Italic">Vibrio alginolyticus</Emphasis>

For the investigation of anti-infection immune response of Pseudosciaena crocea, 160 healthy fish samples were categorized into infected and control groups. Each individual fish in the infected group was injected intraperitoneally (i.p.) with 0.2 ml bacterial suspension of Vibrio alginolyticus in density of 2×10⁷ CFU/ml, while each individual in the control group was injected i.p. with 0.2 ml sterile saline solution (0.85%). It was observed that the artificial injection of V. alginolyticus significantly increased the number of erythrocytes, leucocytes, lymphocytes in peripheral blood as well as peripheral serum antibacterial activity and antibody titer of large yellow croaker, and significantly reduced the number of peripheral blood granulocytes as compared with those in the control group. No significant difference in acid phosphytase and superoxide dismutase activity of serum was detected between the two groups. It is suggested that non-specific immune factors including leucocytes and anti-bacteria substance in peripheral blood played important role at the initial stage of infection, and specific immune factors such as antibody then played important role in response to anti-infection at the latter stage. Supported by the National High Technology Research and Development Program of China (863 program, No. 2007AA09Z115) and Technology Program of Xiamen (No. 3502Z73019)     

Cloning and Analysis of Calmodulin Gene from Porphyra yezoensis Ueda （Bangiales, Rhodophyta）

In order to understand the mechanisms of signal transduction and anti-desiccation mechanisms of Porphyra yezoensis, cDNA and its genomic sequence of Calmodulin gene (CaM) was cloned by the technique of polymerase chain reaction (PCR) based on the analysis of P. yezoensis ESTs from dbEST database. The result shows that the full-length cDNA of CaM consists of 603 bps including an ORF encoding for 151 amino acids and a terminate codon UGA, while the length of genomic sequence is 1231 bps including 2 exons and 1 intron. The average GC content of the coding region is 58.77%, while the GC content of the third position of this gene is as high as 82.23%. Four Ca²⁺ binding sites (EF-hand) are found in this gene. The predicted molecular mass of the deduced peptide is 16688.72 Da and the pI is 4.222. By aligning with known CaM genes, the similarity of CaM gene sequence with homologous genes in Chlamydomonas incerta and Chlamydomonas reinhardtii is 72.7% and 72.2% respectively, and the similarity of the deduced amino acid sequence of CaM gene with homologous genes in C. incerta and C. reinhardtii are both 71.5%. This is the first report on CaM from a species of Rhodophyta.     

黔西南架底金矿床流体包裹体研究

架底金矿是近年来在黔西南新发现的主要赋存于玄武岩中的大型微细粒浸染型金矿床。为查明其成矿流体特征,探讨流体成矿机制,针对矿床不同成矿阶段采取流体包裹体样品开展工作。根据野外观察和室内分析,架底金矿热液成矿期可分为3个阶段:黄铁矿阶段、烟灰色石英阶段和硫化物阶段,其中烟灰色石英阶段为主要成矿阶段。流体包裹体以NaCl-H₂O和CO₂-NaCl-H₂O型为主,黄铁矿阶段富CO₂包裹体,均一温度（T_h）为211~231℃,盐度（wt）为2.10~7.60（% NaCl equiv）;烟灰色石英阶段见大量NaCl-H₂O和CO₂-NaCl-H₂O型包裹体,均一温度（T_h）为182~218℃,盐度（wt）为1.40~5.90（% NaCl equiv）;硫化物阶段包裹体均一温度（T_h）普遍小于183℃,盐度（wt）为0.90~5.30（% NaCl equiv）。激光拉曼光谱分析显示包裹体中含CO₂、CH₄、N₂、SO₂等气相组分,随着成矿流体均一温度、盐度和密度的不断下降,包裹体中气相组分种类也趋于简单。通过计算成矿流体的ρ、P、pH、Eh和f_O2等物理化学参数,表明成矿环境具有中低温、低盐度、低密度、近中性、相对还原及低氧逸度的特征。流体包裹体组合变化表明成矿作用发生在流体CO₂含量不断降低的过程,主成矿阶段流体混合和区域伸展构造引起流体沸腾作用强烈,大量金属成分（黄铁矿、自然金等）快速沉淀形成金矿体。      

Scenario simulation of the geohazard dynamic process of large-scale landslides: a case study of the Xiaomojiu landslide along the Jinsha River

Natural Hazards - Large-scale landslides often cause severe damage due to their long run-out distances and having disaster chain effects. Scenario simulation has been adopted in the current work in...     

Excavation at Hanjing site yields evidence of early rice cultivation in the Huai River more than 8000 years ago

Science China Earth Sciences - Through the analysis of macro- and micro-plant remains, food residues and the rice-field like features from the mid-Neolithic site of Hanjing in the Huai River...     

浙江省入境旅游区域差异与竞争态势

作为外向型经济体系重要组成部分的入境旅游,其发展水平表征区域经济外向竞争力。浙江省入境旅游发展态势较好,但地域差异显著。运用区域差异相关测度方法研究2000—2012年浙江省11个地市入境旅游发展地带内、地带间差异与总差异演变,并尝试用波士顿矩阵测度入境旅游竞争态势。结果表明:1浙江省入境旅游相对差异不断缩小,绝对差异不断扩大;2伴随浙东北内部差异的不断减小,浙西南逐渐成为浙江省入境旅游总差异的主要贡献者;3浙江省入境旅游空间格局呈"双核模式"向"多核模式"演变;4浙江省市际入境旅游竞争力明星类、金牛类较少,入境旅游发展整体水平亟待区域优化。     

样子哨盆地地质特征及其成矿作用

样子哨盆地位于龙岗隆起北西部,具有多时代叠加沉积,多期次构造演化特征。地层主要由上元古界、古生界、中生界、新生界组成,沉积中心由北东向南西转移;区内褶皱构造发育,上元古界褶皱构造以全形紧密褶皱为主,古生界褶皱构造以全开阔线形复式褶皱为主;盆地找矿前景较好,在南西部具备形成矽卡岩型多金属矿的地质条件,南东部沿盆缘断裂具备形成浅成低温热液型金矿的地质条件,盆地中部中生界煤系地层也较发育。