Time series from fisheries often contain multiple missing data.This is a severe limitation that prevents using the data for research on population dynamics,stock assessment,forecasting,and,hence,decision-making around...Time series from fisheries often contain multiple missing data.This is a severe limitation that prevents using the data for research on population dynamics,stock assessment,forecasting,and,hence,decision-making around marine resources.Several methods have been proposed to impute missing data in univariate time series.Still,their performances depend not only on the amount of missing data but also on the data structure.This study compares the performance of twelve imputation methods on the time series of marine fishery landings for six species in the Colombian Pacific Ocean.Unlike other studies,we validate the precision of the imputations in the same target time series that include missing data,using the Known Sub-Sequence Algorithm(KSSA),a novelty validation approach that simulates missing data in known sub-sequences of the target time series.The results showed that the best methods for imputation are Seasonal Decomposition with Kalman filters and Structural Models with Kalman filters fitted by maximum likelihood.Results also show that validating the imputation methods with other time series different to the target time series,leads to wrong imputation methods choices.It is noteworthy that these methods and also the validation framework are mainly suited to time series with non-random distribution of missing data,this is,missing data produced systematically in chunks or clusters with predictable frequency,which are common in marine sciences.展开更多
运用房室模型中二室模型原理,建立药代动力学方程。基于M icrosoft V isual C++6.0的软件开发系统平台,使用MFC高级编程语言建立工程级的开发对象,快速准确的计算渔药理论休药期、理论休药区间和度日。计算结果准确、可靠,软件运行安全...运用房室模型中二室模型原理,建立药代动力学方程。基于M icrosoft V isual C++6.0的软件开发系统平台,使用MFC高级编程语言建立工程级的开发对象,快速准确的计算渔药理论休药期、理论休药区间和度日。计算结果准确、可靠,软件运行安全。帮助养殖户确定给药水产品的上市时间,有利于提高水产品的质量安全。展开更多
Using a nuclear transplantation approach, the integration and expression of the green fluorescent protein (GFP) gene in the embryogenesis of transgenic loach (Misgurnus anguillicaudatus Cantor) have been studied. The ...Using a nuclear transplantation approach, the integration and expression of the green fluorescent protein (GFP) gene in the embryogenesis of transgenic loach (Misgurnus anguillicaudatus Cantor) have been studied. The GFP gene expression is first observed at the gastrula stage, which is consistent with the initiation of cell differentiation of fish embryos. The time course of the foreign gene expression is correlated with the regulatory sequences. The expression efficiency also depends on the gene configuration: the expression of pre-integrating circular plasmid at early embryos is higher than that of the linear plasmid. The integration of the GFP gene is first detected at the blastula stage and lasts for quite a long period. When two types of different plasmids are co-injected into fertilized eggs, the behavior of their integration and expression is not identical.展开更多
文摘Time series from fisheries often contain multiple missing data.This is a severe limitation that prevents using the data for research on population dynamics,stock assessment,forecasting,and,hence,decision-making around marine resources.Several methods have been proposed to impute missing data in univariate time series.Still,their performances depend not only on the amount of missing data but also on the data structure.This study compares the performance of twelve imputation methods on the time series of marine fishery landings for six species in the Colombian Pacific Ocean.Unlike other studies,we validate the precision of the imputations in the same target time series that include missing data,using the Known Sub-Sequence Algorithm(KSSA),a novelty validation approach that simulates missing data in known sub-sequences of the target time series.The results showed that the best methods for imputation are Seasonal Decomposition with Kalman filters and Structural Models with Kalman filters fitted by maximum likelihood.Results also show that validating the imputation methods with other time series different to the target time series,leads to wrong imputation methods choices.It is noteworthy that these methods and also the validation framework are mainly suited to time series with non-random distribution of missing data,this is,missing data produced systematically in chunks or clusters with predictable frequency,which are common in marine sciences.
文摘运用房室模型中二室模型原理,建立药代动力学方程。基于M icrosoft V isual C++6.0的软件开发系统平台,使用MFC高级编程语言建立工程级的开发对象,快速准确的计算渔药理论休药期、理论休药区间和度日。计算结果准确、可靠,软件运行安全。帮助养殖户确定给药水产品的上市时间,有利于提高水产品的质量安全。
文摘Using a nuclear transplantation approach, the integration and expression of the green fluorescent protein (GFP) gene in the embryogenesis of transgenic loach (Misgurnus anguillicaudatus Cantor) have been studied. The GFP gene expression is first observed at the gastrula stage, which is consistent with the initiation of cell differentiation of fish embryos. The time course of the foreign gene expression is correlated with the regulatory sequences. The expression efficiency also depends on the gene configuration: the expression of pre-integrating circular plasmid at early embryos is higher than that of the linear plasmid. The integration of the GFP gene is first detected at the blastula stage and lasts for quite a long period. When two types of different plasmids are co-injected into fertilized eggs, the behavior of their integration and expression is not identical.
