利用1921–2020年的海平面气压、海平面高度、热含量数据以及海冰密集度作为太平洋年代际振荡(Pacific Decadal Oscillation,PDO)指数的预报要素,建立了关于PDO指数时间序列预测的多变量长短期记忆(Long Short Term Memory,LSTM)神经网...利用1921–2020年的海平面气压、海平面高度、热含量数据以及海冰密集度作为太平洋年代际振荡(Pacific Decadal Oscillation,PDO)指数的预报要素,建立了关于PDO指数时间序列预测的多变量长短期记忆(Long Short Term Memory,LSTM)神经网络模型,对比分析了2011–2020年不同时间序列预测模型的PDO指数预测结果,最后利用多变量LSTM神经网络模型实现了2021–2030年的PDO指数预测。结果显示,多变量LSTM神经网络模型的预测值与观测值经过交叉验证后的平均相关系数和均方根误差分别为0.70和0.62;PDO未来10年将一直处于冷位相,PDO神经网络指数出现两次波动,于2025年出现最小值。相比于其他时间序列预测模型,本文采用的多变量LSTM神经网络模型预测结果误差小、拟合效果好,可以作为一种新型的预测PDO指数的手段。展开更多
Advances in the field of stem cells have led to the development of a technology called organoids.Organoids are cell cluster structures formed by the cultivation of stem cells in a three-dimensional environment in vitr...Advances in the field of stem cells have led to the development of a technology called organoids.Organoids are cell cluster structures formed by the cultivation of stem cells in a three-dimensional environment in vitro,and they can simulate the living environment of cells in vivo.Organoids play an important role in the screening of drugs for tumor therapy.Compared with traditional drug screening models,tumor organoid models derived from patient tumors have higher sensitivity,heterogeneity,and stability and can restore the real situation of tumors more effectively.Researchers have conducted a number of researches on the feasibility of using organoid technology in drug screening.By testing and comparing the effects of antitumor drugs in organoids and primary tumors,we can select the most appropriate treatment drugs for patients.In the past ten years,organoids from dozens of tissues and biological sample banks from several main organs have been established,and a large number of anticancer drugs have been screened out.This article summarizes the advantages and disadvantages of traditional drug screening models,discusses the development history of organoid technology,and reviews the research results on organoids from tumor drug screening.In addition,the combination of organoid technology and other modern biotechnologies is put forward to further promote the role of organoid technology in the medical field.Finally,this article reviews the history,progress,and prospect on organoids from the view of antitumor drug screening.展开更多
An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are ass...An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interan-nual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change pro jection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface tem-perature （SST） mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation （MJO） amplitude and tropical cyclone Genesis Potential Index （GPI）, global monsoon precipitation pattern, El Ni-no-Southern Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO） related SST anomalies. However, the perfor-mances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific mon-soon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways pro jection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.展开更多
A regional surface carbon dioxide （C02） flux inversion system, the Tan-Tracker-Region, was developed by incor- porating an assimilation scheme into the Community Multiscale Air Quality （CMAQ） regional chemical tra...A regional surface carbon dioxide （C02） flux inversion system, the Tan-Tracker-Region, was developed by incor- porating an assimilation scheme into the Community Multiscale Air Quality （CMAQ） regional chemical transport model to resolve fine-scale CO2 variability over East Asia. The proper orthogonal decomposition-based ensemble four-dimensional variational data assimilation approach （POD-4DVar） is the core algorithm for the joint assimilation framework, and simultaneous assimilations of CO2 concentrations and surface CO2 fluxes are applied to help reduce the uncertainty in initial CO2 concentrations. A persistence dynamical model was developed to describe the evolu- tion of the surface CO2 fluxes and help avoid the ＂signal-to-noise＂ problem; thus, CO2 fluxes could be estimated as a whole at the model grid scale, with better use of observation information. The performance of the regional inversion system was evaluated through a group of single-observation-based observing system simulation experiments （OSSEs）. The results of the experiments suggest that a reliable performance of Tan-Tracker-Region is dependent on certain assimilation parameter choices, for example, an optimized window length of approximately 3 h, an ensemble size of approximately 100, and a covariance localization radius of approximately 320 km. This is probably due to the strong diurnal variation and spatial heterogeneity in the fine-scale CMAQ simulation, which could affect the perform- ance of the regional inversion system. In addition, because all observations can be artificially obtained in OSSEs, the performance of Tan-Tracker-Region was further evaluated through different densities of the artificial observation net- work in different CO2 flux situations. The results indicate that more observation sites would be useful to systematic- ally improve the estimation of CO2 concentration and flux in large areas over the model domain. The work presented here forms a foundation for future research in which a thorough estimation of CO2 flux variability over East Asia could be performed with the regional inversion system.展开更多
文摘利用1921–2020年的海平面气压、海平面高度、热含量数据以及海冰密集度作为太平洋年代际振荡(Pacific Decadal Oscillation,PDO)指数的预报要素,建立了关于PDO指数时间序列预测的多变量长短期记忆(Long Short Term Memory,LSTM)神经网络模型,对比分析了2011–2020年不同时间序列预测模型的PDO指数预测结果,最后利用多变量LSTM神经网络模型实现了2021–2030年的PDO指数预测。结果显示,多变量LSTM神经网络模型的预测值与观测值经过交叉验证后的平均相关系数和均方根误差分别为0.70和0.62;PDO未来10年将一直处于冷位相,PDO神经网络指数出现两次波动,于2025年出现最小值。相比于其他时间序列预测模型,本文采用的多变量LSTM神经网络模型预测结果误差小、拟合效果好,可以作为一种新型的预测PDO指数的手段。
基金This work was supported by:National 13th Five-Year Science and Technology Plan Major Projects of China(2017ZX10203205)National Key R&D Plan(2017YFA0104304)+6 种基金National Natural Science Foundation of China(81770648,81972286)Guangdong Natural Science Foundation(2018A030313259,2015A030312013)Science and Technology Program of Guangdong Province(2017B020209004,20169013,2020B1212060019)Science and Technology Program of Guangzhou City(201508020262)Guangdong Basic and Applied Basic Research Foundation(2019A1515110654,2020A1515010574)the Fundamental Research Funds for the Central Universities(20ykpy38)and China Postdoctoral Science Foundation(2019TQ0369,2020M672987).
文摘Advances in the field of stem cells have led to the development of a technology called organoids.Organoids are cell cluster structures formed by the cultivation of stem cells in a three-dimensional environment in vitro,and they can simulate the living environment of cells in vivo.Organoids play an important role in the screening of drugs for tumor therapy.Compared with traditional drug screening models,tumor organoid models derived from patient tumors have higher sensitivity,heterogeneity,and stability and can restore the real situation of tumors more effectively.Researchers have conducted a number of researches on the feasibility of using organoid technology in drug screening.By testing and comparing the effects of antitumor drugs in organoids and primary tumors,we can select the most appropriate treatment drugs for patients.In the past ten years,organoids from dozens of tissues and biological sample banks from several main organs have been established,and a large number of anticancer drugs have been screened out.This article summarizes the advantages and disadvantages of traditional drug screening models,discusses the development history of organoid technology,and reviews the research results on organoids from tumor drug screening.In addition,the combination of organoid technology and other modern biotechnologies is put forward to further promote the role of organoid technology in the medical field.Finally,this article reviews the history,progress,and prospect on organoids from the view of antitumor drug screening.
基金Supported jointly by the National Natural Science Foundation of China(41125017 and 41330423)National(Key) Basic Research and Development(973) Program of China(2010CB951904)Public Science and Technology Research Project Funds of Ocean(201105019-3)
文摘An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interan-nual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change pro jection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface tem-perature （SST） mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation （MJO） amplitude and tropical cyclone Genesis Potential Index （GPI）, global monsoon precipitation pattern, El Ni-no-Southern Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO） related SST anomalies. However, the perfor-mances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific mon-soon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways pro jection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.
基金Supported by the National Natural Science Foundation of China(41130528)National High Technology Research and Development Program of China(2013AA122002)+1 种基金Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues(XDA05040404)National Key Technology Research and Development Program of China(2016YFC0202103)
文摘A regional surface carbon dioxide （C02） flux inversion system, the Tan-Tracker-Region, was developed by incor- porating an assimilation scheme into the Community Multiscale Air Quality （CMAQ） regional chemical transport model to resolve fine-scale CO2 variability over East Asia. The proper orthogonal decomposition-based ensemble four-dimensional variational data assimilation approach （POD-4DVar） is the core algorithm for the joint assimilation framework, and simultaneous assimilations of CO2 concentrations and surface CO2 fluxes are applied to help reduce the uncertainty in initial CO2 concentrations. A persistence dynamical model was developed to describe the evolu- tion of the surface CO2 fluxes and help avoid the ＂signal-to-noise＂ problem; thus, CO2 fluxes could be estimated as a whole at the model grid scale, with better use of observation information. The performance of the regional inversion system was evaluated through a group of single-observation-based observing system simulation experiments （OSSEs）. The results of the experiments suggest that a reliable performance of Tan-Tracker-Region is dependent on certain assimilation parameter choices, for example, an optimized window length of approximately 3 h, an ensemble size of approximately 100, and a covariance localization radius of approximately 320 km. This is probably due to the strong diurnal variation and spatial heterogeneity in the fine-scale CMAQ simulation, which could affect the perform- ance of the regional inversion system. In addition, because all observations can be artificially obtained in OSSEs, the performance of Tan-Tracker-Region was further evaluated through different densities of the artificial observation net- work in different CO2 flux situations. The results indicate that more observation sites would be useful to systematic- ally improve the estimation of CO2 concentration and flux in large areas over the model domain. The work presented here forms a foundation for future research in which a thorough estimation of CO2 flux variability over East Asia could be performed with the regional inversion system.
