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791.
Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole, Cynoglossus semilaevis, were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic males with female genotypes, neo-males are harmful in C. semilaevis aquaculture because they reduce overall production. The present study evaluated the difference in the growth-related traits: total length (TL), body weight (BW) and square root of body weight (SQ_BW) at the age of 570 days between normal and neo-male offspring (neo-males used as male parents). The difference in the proportion of females between normal and neo-male offspring was also assessed. Based on the linear mixed model, restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP) were used to estimate various (co)variance components and estimated breeding values (EBVs) of growth-related traits. As a result, all the mean values of the three studied traits were significantly larger in normal offspring than in neo-male offspring. Additionally, the female proportion was significantly larger in normal offspring than in neo-male offspring. Heritability was 0.128±0.066 2 for TL, 0.128±0.065 5 for BW and 0.132±0.062 9 for SQ_BW, all of which were low level heritabilities. The correlation coefficients of EBVs and phenotypic values of the target traits were 0.516 for TL, 0.524 for BW and 0.506 for SQ_BW, all of which were highly significant (P <0.01). Genetic correlations among TL, BW and SQ_BW were positive high (0.921–0.969) and higher than those of phenotype (0.711–0.748), both of which had low standard errors (0.063–0.123 for genotype, and 0.010–0.018 for phenotype). Compared with normal offspring, neo-male offspring have lower breeding values for each studied trait through EBVs comparison. Therefore, neo-male offspring should not be used as broodstock in a C. semilaevis breeding programs.  相似文献   
792.
Two new species of the genus Cobitis from southern China, C. hereromacula from the Luohe River in Guangdong Province and C. baishagensis from the Nandujiang River in Hainan Province, are described and illustrated here. C. hereromacula can be distinguished from its congeners by possessing the following combination of characteristics: absence of the second and third pigmentary zones of Gambetta; 13–16 oval blotches on the dorsum and 10–13 vertical, elongated triangular blotches below the midlateral line with more than 20 vertical dark brown bars between them; 6–7 narrow rows of dark spots on the caudal fin; a vertical oval spot smaller than the eye diameter on the upper part of the caudal peduncle; pointed mental lobes of the lower lip pointed with a slightly filiform tip; one slender and long needle-shaped lamina circularis at the base of the first branched ray of the male pectoral fins. C. baishagensis can be distinguished from its congeners by the fourth Gambetta zone being covered by 10–12 transverse elongated blotches; 4–5 narrow rows of dark spots on the caudal fin; a vertical blotch smaller than the eye diameter on the upper part of the caudal peduncle; males with a slender and long needle-shaped lamina circularis at the second branched pectoral fin ray in males; large scales with a slightly large focal zone; undeveloped mental lobes with a lower lip that does not end posteriorly in a filiform tip.  相似文献   
793.
Based on the analysis of the enrichment characteristics of Hg and MeHg in bird feathers from Caohai National Nature Reserve in Guizhou, the risks of Hg pollution to the birds from Caohai wetland have been evaluated. The total Hg content of bird feathers ranges from 40 to 5058 ng/g with an average of 924 ng/g. The content of MeHg is significantly correlated with total Hg (r = 0.68, p < 0.01), and the content are among 0.75 and 113 ng/g. The total Hg content in the birds feathers is significantly dependent on their feeding habits, which is mainly in accordance with the following rule: carnivorous birds > omnivorous birds that are mainly carnivorous > omnivorous birds that are mainly herbivorous. There are also differences in the Hg enrichment ability in the different parts of bird feathers, and the total Hg and MeHg content in the wing feathers are significantly higher than that in the other parts of feathers. The bioaccumulation coefficients of aqueous Hg and MeHg by bird feathers are 0.9 × 104–112.13 × 104 (mean value is 20.47 × 104) and 0.47 × 104–70.4 × 104 (mean value is 9.52 × 104), respectively. Although the whole Hg level in Caohai bird feathers is not too high, the Hg content in some carnivorous birds exceeds over or approaches the abnormal threshold when birds are breeding (5 μg/g), which indicates that the birds in Caohai wetland are faced with some risks of ecological Hg pollution.  相似文献   
794.
The Shihu gold deposit, located in the middle-south section of the core of the Fuping mantle branch structure, is hosted in the Archean Fuping Group and adjacent to the quartz diorite porphyrite. The gold deposit is the only large gold deposit with reserves of more than 30 tons gold discovered in western Hebei Province so far. In order to constrain the timing of mineralization of this ore deposit, this paper focuses on the isotopic dating of zircon and pyrite. Zircons in gold-bearing quartz veins are magmatic in origin and no hydrothermal zircon has been found in such quartz veins, indicating that zircons were derived from the wall rocks. U–Pb ages of zircons fall mainly in the two domains: 2492 ± 82 and 136 ± 4 Ma, respectively, indicative of the contribution of the Fuping-Group TTG gneiss and Yanshanian igneous rocks, respectively. The Re–Os isotopic compositions of pyrites in the gold-bearing quartz veins yield an isochron age of 127 ± 31 Ma. Combined with other dating results, we suggest that the main metallogenic age of the Shihu gold deposit is 120–127 Ma.  相似文献   
795.
796.
泾阳南塬蒋刘4#滑坡特征及成因机制   总被引:3,自引:3,他引:0       下载免费PDF全文
2016年3月6日,泾阳南塬蒋刘村发生了约2×104 m3的小型黄土滑坡。滑坡发生后,在对滑坡现场进行详细的地质调查基础上,结合无人机航测和三维激光扫描综合手段,对滑坡的基本特征及成因机理进行了初步分析。结果表明:长期引水灌溉是滑坡发生的基本条件;坡脚滞水软化作用、与灌溉渠较短的渗透距离、坡脚冻结黄土春季解冻是导致滑体发生的直接原因;底部饱和泥化黄土的铺垫及导流作用,是导致其滑程较远的根本原因。该类滑坡近几年来发生频率较高,为泾阳南塬滑坡演化后期的主要发生类型,具有一定的特殊性,值得深入研究。  相似文献   
797.
大兴安岭呼中镇钼多金属矿床产于早白垩世碎裂花岗岩中,矿体形态似层状、脉状或透镜状。成矿阶段分为辉钼矿阶段、铜铅锌阶段、方解石阶段等3个阶段。本矿床中的包裹体主要有气液H_2O包裹体、气相H_2O包裹体、含子矿物H_2O包裹体,CO_2包裹体、CO_2-H_2O包裹体等五大类。辉钼矿阶段均一温度为209.2℃413.4℃,盐度ω(NaCleq)为0.53%16.53%,平均值7.3%,属中低盐度,成矿压力在53.3 68.5 MPa,相应的成矿深度为2 052 2 807 m;铜铅锌阶段为191.5℃351.0℃,盐度ω(NaCleq)为0.88%34.24%,平均值3.96%,属低盐度;方解石阶段207.2℃233.5℃,盐度ω(NaCleq)为3.55%4.18%,平均值3.77%,为低盐度。从辉钼矿阶段到铜铅锌阶段再到方解石阶段,温度及盐度逐渐降低。辉钼矿成矿压力在53.3 72.9 MPa,成矿深度为2 052 2 807 m。成矿过程中发生了CO_2-H_2O不混溶作用,这是导致辉钼矿沉淀的主要机制。矿床类型属中低温浅成热液型矿床。  相似文献   
798.
根据近年来的同位素年代学资料,对分布于辽北地区的一套构造变质岩系("开原岩群"或"清河镇岩群")进行了重新认识和划分,并将其重新定义为清河构造混杂岩,由中太古代、新太古代、中元古代、新元古代、二叠纪等不同时代、不同构造环境的地质体组成.其中,中太古代、新太古代、中元古代岩石来自华北克拉通,而新元古代、二叠纪岩石则来自兴蒙造山带.将原沈家堡子岩组重新划分为新太古代变质表壳岩和中-新太古代变质深成岩,原板石沟岩组(或芦家堡子岩组)厘定为中元古代石门岩组,原照北山岩组重新划分为新元古代南平岩片和晚二叠世照北山岩组,将原佟家屯岩组和尖山子火山岩合并为晚二叠世佟家屯岩组.最后,提出了清河构造混杂岩带为华北克拉通与兴蒙造山带的界线以及古亚洲洋在华北板块北缘东段的最终闭合时间为中三叠世早期(约245Ma)的认识.  相似文献   
799.
Measuring gas content is an essential step in estimating the commerciality of gas reserves. In this study,eight shale core samples from the Mouye-1 well were measured using a homemade patented gas desorption apparatus to determine their gas contents. Due to the air contamination that is introduced into the desorption canister, a mathematical method was devised to correct the gas quantity and quality.Compared to the chemical compositions of desorbed gas, the chemical compositions of residual gas are somewhat different. In residual gas, carbon dioxide and nitrogen record a slight increase, and propane is first observed. This phenomenon may be related to the exposure time during the transportation of shale samples from the drilling site to the laboratory, as well as the differences in the mass, size and adsorptivity of different gas molecules. In addition to a series of conventional methods, including the USBM direct method and the Amoco Curve Fit(ACF) method, which were used here for lost gas content estimation, a Modified Curve Fit(MCF) method, based on the 'bidisperse' diffusion model, was established to estimate lost gas content. By fitting the ACF and MCF models to gas desorption data, we determined that the MCF method could reasonably describe the gas desorption data over the entire time period, whereas the ACF method failed. The failure of the ACF method to describe the gas desorption process may be related to its restrictive assumption of a single pore size within shale samples. In comparison to the indirect method, this study demonstrates that none of the three methods studied in this investigation(USBM, ACF and MCF) could individually estimate the lost gas contents of all shale samples and that the proportion of free gas relative to total gas has a significant effect on the estimation accuracy of the selected method. When the ratio of free gas to total gas is lower than 45%, the USBM method is the best for estimating the lost gas content, whereas when the ratio ranges from 45% to 75% or is more than 75%, the ACF and MCF methods, are the best options respectively.  相似文献   
800.
Upscaling permeability of grid blocks is crucial for groundwater models. A novel upscaling method for three-dimensional fractured porous rocks is presented. The objective of the study was to compare this method with the commonly used Oda upscaling method and the volume averaging method. First, the multiple boundary method and its computational framework were defined for three-dimensional stochastic fracture networks. Then, the different upscaling methods were compared for a set of rotated fractures, for tortuous fractures, and for two discrete fracture networks. The results computed by the multiple boundary method are comparable with those of the other two methods and fit best the analytical solution for a set of rotated fractures. The errors in flow rate of the equivalent fracture model decrease when using the multiple boundary method. Furthermore, the errors of the equivalent fracture models increase from well-connected fracture networks to poorly connected ones. Finally, the diagonal components of the equivalent permeability tensors tend to follow a normal or log-normal distribution for the well-connected fracture network model with infinite fracture size. By contrast, they exhibit a power-law distribution for the poorly connected fracture network with multiple scale fractures. The study demonstrates the accuracy and the flexibility of the multiple boundary upscaling concept. This makes it attractive for being incorporated into any existing flow-based upscaling procedures, which helps in reducing the uncertainty of groundwater models.  相似文献   
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