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371.
The estimation of genetic parameters has played an important role in animal selective breeding for growth traits.Recently studies show that molecular markers can be incorporated into genetic evaluations. In order to improve the performance of an incomplete pedigree(i.e, only parents are known) in the genetic evaluations, 12 microsatellite markers have been applied in the estimation of the genetic parameters for body weight in a farmed population(n=1 890) of juvenile turbot(Scophthalmus maximus L.). A new relatedness called parental molecular relatedness(PMR) is estimated based on results of genotyping of 48 parents(31 males, 17 females) with microsatellites markers. The feasibility of PMR in estimation of genetic parameters is verified by comparison with pedigree related(PR) which is obtained from a complete pedigree. The results demonstrate that a high correlation(0.872) between them is found. Heritabilities are estimated using the PMR(0.52±0.13) and PR(0.55±0.22) with the same animal model. A cross-validation shows that the predictive abilities of models using the PMR and the PR are identical(0.81). From that, a conclusion can be made that PMR and PR predicted genetic values equally well in a population of juvenile turbot. Therefore PMR can be applied as an alternative of the PR when only parents are known. However, for a better performance, more markers and more families should be included in a further study.  相似文献   
372.
373.
三沙湾盐田港养殖海域沉积物中的有机碳、氮和磷   总被引:1,自引:0,他引:1  
于2012年8月(夏季)、11月(秋季)和2013年2月(冬季)、5月(春季)共4个航次对三沙湾盐田港养殖海域表层沉积物组成成分及其变化趋势进行调查分析,并采用单因子污染指数(Pi)对沉积物质量进行评价。结果表明不同功能区沉积物中有机氮(TN)、总磷(TP)和有机碳(OC)含量差异显著(P0.05),TN和TP含量4季变化范围分别是0.15~1.39 g/kg和0.11~1.08 g/kg,平均值分别为(0.89±0.36)g/kg和(0.56±0.26)g/kg。OC含量在1.00~14.71 g/kg之间,平均值为(8.26±3.78)g/kg。各站位沉积物中TN污染指数4季变化范围为0.25~2.53,4季超标率分别为67%、81%、80%和90%;各站位TP污染指数4季变化范围为0.18~2.63,4个季节超标率分别为35%、80%、40%和51%;各季节OC含量均未超标;OC/N原子比全年变化范围在8.4~10.3之间,平均值为8.9±0.6。较弱的水流交换条件和海水养殖,特别是海水网箱养殖,是造成沉积物污染的主要原因,开展多营养层次的综合养殖模式是促进盐田港海水养殖可持续发展的有效途径。  相似文献   
374.
50年来北海市滨海湿地景观格局变化及其驱动机制   总被引:2,自引:2,他引:0  
以1955~2004年遥感影像为数据源,结合野外调查,运用景观生态学原理,研究50 a间北海市滨海湿地的景观格局及其动态变化。结果表明,50 a间北海市滨海湿地呈整体退化趋势,潮间砂质海滩、潮间淤泥质海滩、红树林滩、小型岛屿湿地减少;景观格局指数显示1977年、1998年是北海市滨海湿地较明显变化的拐点。1977年人类活动影响增加,滨海湿地稍有退化,湿地景观多样性指数减小,优势度指数增加,均匀度指数减小、景观总面积指数降至最低值。1988年湿地保护力度加大,湿地略为好转,景观多样性指数、优势度指数、均匀度指数则呈相反规律。1998年湿地受到的极端气候灾害、人类干扰程度加大,平均斑块分形维数下降,斑块密度指数、景观斑块数破碎化指数呈最高值。湿地景观格局指数的变化,反映了围垦改造、互花米草的生物入侵、城市污染、极端气候灾害等对景观格局的影响,人类活动是北海市滨海湿地景观格局变化的主要驱动因子。  相似文献   
375.
近年来厄尔尼诺期间北赤道流输运的年际变化   总被引:1,自引:0,他引:1  
为了研究近年来厄尔尼诺期间北赤道流输运的年际变化,本文利用海洋客观分析数据MOAA GPV(Grid Point Value of the Monthly Objective Analysis)以及P-vector方法计算了北太平洋绝对地转流,探讨了2001~2013年期间厄尔尼诺与北赤道流输运之间的关系。在此期间发生的4次厄尔尼诺事件中,北赤道流输运在2002~2003、2006~2007、2009~2010年的厄尔尼诺成熟期都出现了明显的增强,但是在2004~2005年的厄尔尼诺成熟期并没有明显的增强。进一步分析发现,在2002~2003年、2006~2007年、2009~2010年的厄尔尼诺成熟期,10°N以南的热带西北太平洋区域出现了负的海面高度异常和气旋式环流异常,这主要是由热带环流区域出现的西风异常和正的Ekman抽吸通过Rossby波西传到热带西太平洋区域所致;但是在2004~2005年厄尔尼诺成熟期,海面温度异常的分布明显不同,西风异常和正的Ekman抽吸异常明显北移,导致负的海面高度异常和气旋式环流异常出现在了10°N以北的西北太平洋区域,使得北赤道流输运在2004~2005年的厄尔尼诺成熟期没有明显的增强。  相似文献   
376.
The fine-scale heterogeneity of porous media affects the large-scale transport of solutes and contaminants in groundwater and it can be reproduced by means of several geostatistical simulation tools. However, including the available geological information in these tools is often cumbersome. A hierarchical simulation procedure based on a binary tree is proposed and tested on two real-world blocks of alluvial sediments, of a few cubic meters volume, that represent small-scale aquifer analogs. The procedure is implemented using the sequential indicator simulation, but it is so general that it can be adapted to various geostatistical simulation tools, improving their capability to incorporate geological information, i.e., the sedimentological and architectural characterization of heterogeneity. When compared with a standard sequential indicator approach on bi-dimensional simulations, in terms of proportions and connectivity indicators, the proposed procedure yields reliable results, closer to the reference observations. Different ensembles of three-dimensional simulations based on different hierarchical sequences are used to perform numerical experiments of conservative solute transport and to obtain ensembles of equivalent pore velocity and dispersion coefficient at the scale length of the blocks (meter). Their statistics are used to estimate the impact of the variability of the transport properties of the simulated blocks on contaminant transport modeled on bigger domains (hectometer). This is investigated with a one-dimensional transport modeling based on the Kolmogorov-Dmitriev theory of branching stochastic processes. Applying the proposed approach with diverse binary trees and different simulation settings provides a great flexibility, which is revealed by the differences in the breakthrough curves.  相似文献   
377.
This paper presents a new experimental campaign aimed at reproducing tsunamis generated by landslides at the flank of conical islands. In order to describe in high details the wave field around the island a special acquisition system, which consists of both fixed and movable wave gauges, has been employed. Indeed, each experiment has been repeated several times by changing the configuration of the movable gauges, then obtaining a single virtual experiment with high spatial resolution measurements. Fixed run-up gauges measure the waves at fixed locations to statistically quantify the repeatability of the experiments. Selected experimental results are illustrated within the paper that is mainly aimed at defining a benchmark dataset, available on request, for the development/calibration/validation of analytical and numerical models of tsunamis generated by landslides.  相似文献   
378.
Mountainous areas surrounding the Campanian Plain and the Somma-Vesuvius volcano (southern Italy) are among the most risky areas of Italy due to the repeated occurrence of rainfall-induced debris flows along ash-fall pyroclastic soil-mantled slopes. In this geomorphological framework, rainfall patterns, hydrological processes taking place within multi-layered ash-fall pyroclastic deposits and soil antecedent moisture status are the principal factors to be taken into account to assess triggering rainfall conditions and the related hazard. This paper presents the outcomes of an experimental study based on integrated analyses consisting of the reconstruction of physical models of landslides, in situ hydrological monitoring, and hydrological and slope stability modeling, carried out on four representative source areas of debris flows that occurred in May 1998 in the Sarno Mountain Range. The hydrological monitoring was carried out during 2011 using nests of tensiometers and Watermark pressure head sensors and also through a rainfall and air temperature recording station. Time series of measured pressure head were used to calibrate a hydrological numerical model of the pyroclastic soil mantle for 2011, which was re-run for a 12-year period beginning in 2000, given the availability of rainfall and air temperature monitoring data. Such an approach allowed us to reconstruct the regime of pressure head at a daily time scale for a long period, which is representative of about 11 hydrologic years with different meteorological conditions. Based on this simulated time series, average winter and summer hydrological conditions were chosen to carry out hydrological and stability modeling of sample slopes and to identify Intensity-Duration rainfall thresholds by a deterministic approach. Among principal results, the opposing winter and summer antecedent pressure head (soil moisture) conditions were found to exert a significant control on intensity and duration of rainfall triggering events. Going from winter to summer conditions requires a strong increase of intensity and/or duration to induce landslides. The results identify an approach to account for different hazard conditions related to seasonality of hydrological processes inside the ash-fall pyroclastic soil mantle. Moreover, they highlight another important factor of uncertainty that potentially affects rainfall thresholds triggering shallow landslides reconstructed by empirical approaches.  相似文献   
379.
The double‐spike method with multi‐collector inductively coupled plasma‐mass spectrometry was used to measure the Mo mass fractions and isotopic compositions of a set of geological reference materials including the mineral molybdenite, seawater, coral, as well as igneous and sedimentary rocks. The long‐term reproducibility of the Mo isotopic measurements, based on two‐year analyses of NIST SRM 3134 reference solutions and seawater samples, was ≤ 0.07‰ (two standard deviations, 2s, n = 167) for δ98/95Mo. Accuracy was evaluated by analyses of Atlantic seawater, which yielded a mean δ98/95Mo of 2.03 ± 0.06‰ (2s, n = 30, relative to NIST SRM 3134 = 0‰) and mass fraction of 0.0104 ± 0.0006 μg g?1 (2s, n = 30), which is indistinguishable from seawater samples taken world‐wide and measured in other laboratories. The comprehensive data set presented in this study serves as a reference for quality assurance and interlaboratory comparison of high‐precision Mo mass fractions and isotopic compositions.  相似文献   
380.
海洋水下文化遗产是不可再生的文化资源,在全球海洋开发的浪潮中,做好海洋水下文化遗产的调查和保护是迫切和急需的。文章概述世界上传统海洋大国对海洋水下文化遗产保护和管理的经验,分析我国海洋水下文化遗产保护和管理存在的问题,并提出相关对策:查清海洋水下文化遗产的分布、数量和特征等信息,了解海洋水下文化遗产分布区的地质地貌环境、水动力环境和保存环境条件,建立海洋水下文化遗产档案馆和数据库系统;完善与海洋水下文化遗产保护相关的法规、政策和标准规范等,提升执法效率,做好海洋水下文化遗产保护和海洋开发利用的协调工作;建立海洋水下文化遗产保护示范区,传承和弘扬蓝色文明,实现海洋水下文化遗产的社会利用和可持续保护。  相似文献   
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