检索结果-南通市图书馆

Dynamic evolution of an SVEIR model with variants and non-pharmaceutical interventions for controlling COVID-19

Journal of Biosafety and Biosecurity 2024年第2期6卷 67-75页

作者： Ruiyang Zhou Shaojian Cai Guangmin Chen Senzhong Huang Zhen jin Zhihang Peng Weichuan Lin Fengying Wei Kuicheng Zheng school of Mathematics and statistics Fuzhou UniversityFuzhou 350116FujianChina Fujian Provincial Center for Disease Control and Prevention Fuzhou 350012FujianChina school of statistics and Data Science ZhiYing Research Center for Health DataNankai UniversityTianjin 300071China Complex Systems Research Center Shanxi UniversityTaiyuan 030006ShanxiChina Department of Biostatistics School of Public HealthNanjing Medical UniversityNanjing 211166JiangsuChina school of Mathematics and statistics Fujian Normal UniversityFuzhou 350007FujianChina Center for Applied Mathematics of Fujian Province Fuzhou UniversityFuzhou 350116FujianChina Key Laboratory of Operations Research and Control of Universities in Fujian Fuzhou UniversityFuzhou 350116FujianChina Fujian Provincial Key Laboratory of Zoonosis Research Fuzhou 350001FujianChina Teaching Base of the school of Public Health of Fujian Medical university Fuzhou 350001FujianChina

The epidemiological characteristics and distributions of two epidemics in Fujian Province of Southeast china were attributed to the complex interactions among variant,host,and non-pharmaceutical interventions(NPIs).All reported cases in the Putian epidemic(September 8–October 2,2021,Delta variant B.1.617.2)and Fuzhou epidemic(October 22–November 18,2022,Omicron variant BA.5.2)were classified by sex,age group,occupation,and location in this *** surveillance data from the Fujian Provincial Center for Disease Control and Prevention,we established a virus-oriented SVEIR(Susceptible–Vaccinated–Exposed–Infected–Recovered)model to investigate the dynamic evolution features of these two variants and the effects of *** optimal simulations were carried out with variants and scenario *** scenario investigations showed that NPIs significantly reduced the transmission risk and infection scales of COVID-19,and that the Omicron variant was more infectious than the Delta ***,the dynamic investigations revealed the increasing tendencies from Delta to Omicron,such as the basic reproduction number,infection rate,percentage of high-risk cases,and the growth *** tendencies were also identified,such as the average recovery period,the awareness delay,and the percentage of symptomatic *** study highlighted that NPIs played critical roles in successfully containing the two *** interventions are strongly recommended to public health policymakers.

关键词： COVID-19 SVEIR model Transmission dynamics Non-pharmaceutical interventions Delta variant Omicron variant

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Duplication and Divergence of Floral MADS-Box Genes in Grasses： Evidence for the Generation and Modification of Novel Regulators

引用

Journal of Integrative Plant Biology 2007年第6期49卷 927-939页

作者： Guixia Xu hongzhi Kong State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Graduate university of the Chinese Academy of Sciences Beijing 100039 China

The process of flowering is controlled by a hierarchy of floral genes that act as flowering time genes, inflorescence/floral meristem Identity genes, and/or floral organ-identity genes. The most important and well-characterized floral genes are those that belong to the MADS-box family of transcription factors. Compelling evidence suggests that floral MADS-box genes have experienced a few large-scale duplication events. In particular, the precore eudicot duplication events have been considered to correlate with the emergence and diversification of core eudicots. Duplication of floral MADS-box genes has also been documented in monocots, particularly In grasses, although a systematic study is lacking. In the present study, by conducting extensive phylogenetlc analyses, we identified pre-Poaceae gene duplication events in each of the AP1, P1, AG, AGL11, AGL2/3.4, and AGL9gene lineages. Comparative genomic studies further indicated that some of these duplications actually resulted from the genome doubling event that occurred 66-70 million years ago （MYA）. In addition, we found that after gene duplication, exonization （of intron sequences） and pseudoexonization （of exon sequences） have contributed to the divergence of duplicate genes in sequence structure and, possibly, gene function.

关键词： divergence Oryza sativa gene duplication genome doubling event grasses MADS-box genes.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

新发展格局下国内国际循环测度及对经济增长的影响研究

引用

科技和产业 2024年第2期24卷 58-63页

作者：金官丽吴洋兰州财经大学统计与数据科学学院兰州730020

在新发展格局背景下,基于2010—2021年3.个省份构建国内和国际循环指标体系,采用熵权-Topsis法测度国内和国际循环发展水平指数,在此基础上,根据面板双向固定效应模型分析国内循环、国际循环、双循环以及双循环的平方项对经济增长的影响... 详细信息

在新发展格局背景下,基于2010—2021年3.个省份构建国内和国际循环指标体系,采用熵权-Topsis法测度国内和国际循环发展水平指数,在此基础上,根据面板双向固定效应模型分析国内循环、国际循环、双循环以及双循环的平方项对经济增长的影响,并进行异质性和稳健性检验。经过分析得出结论,国内循环和国际循环指数呈现上升趋势,且发展水平较好的主要集中在经济发达地区,东部地区发展水平高于中部和西部地区;国内循环和双循环对经济增长有显著的正向影响,而双循环的平方项呈现负向影响。据此提出,加强国内外循环,优化产业结构,增加多样化进出口;实施区域差异化政策,重点发展欠发达地区;提升南北合作,实现资源优势互补;减少贸易壁垒,增加市场开放度;提升竞争力,开拓国际市场。

关键词：新发展格局国内国际循环测度熵权-Topsis法经济增长双向固定效应模型

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Versatile synthesis of yolk/shell hybrid nanocrystals via ion-exchange reactions for novel metal/semiconductor and semiconductor/semiconductor conformations

引用

Nano Research 2017年第9期10卷 2977-2987页

作者： Muwei Ji Xinyuan Li hongzhi Wang Liu Huang Meng Xu Jia Liu Jiajia Liu jin Wang Jiatao Zhang beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China Graduate school at Shenzhen Tsinghua University Shenzhen 518055 China

Yolk/shell (Y–S) hybrid nanoarchitectures, owing to the interior voids created for individualized catalyst applications, have emerged as new candidates for effectively isolating catalytic species. However, the well-defined hollow interiors with flexible core and shell compositions—such as noble-metal cores, metal-oxide cores, and widespread semiconductor shells—and a flexible anisotropic shape are far from the requirements. In particular, the introduction of catalytic noble metals or metal-oxide nanocrystals (NCs) with isotropic or anisotropic shapes into various hollow semiconductor structures with well-defined morphologies has been rarely reported but is urgently needed. Herein, we propose a strategy involving the careful sulfuration of as-prepared cavity-free core/shell NCs or metal-oxide NCs followed by phosphine-initialized cation-exchange reactions for preparing metal@semiconductor and metal oxide@semiconductor (II-VI) Y–S NCs. The geometry, size, and conformations of the core and shell are fully and independently considered. New and unprecendented metal@semiconductor and metal oxide@semiconductor (II-VI) Y–S NCs are prepared via widespread phosphine-initialized cation-exchange reactions.

关键词： anion exchange cation exchange yolk/shell colloidal hybrid nanocrystals metal/semiconductor

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical implementation and evaluation of resolvent-based estimation for space-time energy spectra in turbulent channel flows

引用

Acta Mechanica Sinica 2020年第4期36卷 775-788页

作者： Bowen yang Guodong jin Ting Wu Zixuan yang Guowei He State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

Resolvent operator has been increasingly used to investigate turbulent flows and develop control ***,Towne et al.(J Fluid Mech 883.A17,2020)proposed a resolvent-based estimation(RBE)method for predicting turbulent statistics in a channel *** this paper,we utilize the RBE method to predict the root-mean-square(RMS)and space-time energy spectra of streamwise velocity fluctuation,where the input is the space-time energy spectra at a reference horizontal plane located in the logarithmic layer and the output is the space-time energy spectra in the buffer *** explicit formulas for the RBE method are given in detail for numerical *** results show the capability of the RBE method in the prediction of the convection velocity and bandwidth of the space-time energy ***,we make a systematic evaluation of the performance of the RBE method by varying the input configurations,including the wall-normal location of the reference plane,the inclusion or exclusion of the pressure as an input variable,the implementation approach of the pressure boundary condition,and the choice of the window *** is found that the results of both RMS velocity and space-time energy spectra obtained from the RBE method are sensitive to the location of the reference ***,the pressure boundary conditions and inclusion of pressure as an input do not cause significant change in the RMS velocity and space-time energy *** it does not influence the prediction of the RMS velocity,a window function is found crucial in the RBE method for the prediction of the space-time energy spectra.

关键词： Space-time energy spectra Turbulent channel flow Resolvent operator

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

统计流形上的等仿射结构(英文)

引用

四川大学学报（自然科学版） 2009年第4期46卷 881-885页

作者：金迎迎贾方四川大学数学学院成都610064 五邑大学数理系江门529020

作者首先研究了等仿射几何与贝叶斯统计学之间的关系,这里贝叶斯统计学的先验分布被看作统计流形上的体积形式,然后利用统计流形上α平行先验估计和体积形式的关系,结合子流形上的基本方程和基本公式给出了一个统计子流形上具有等仿射... 详细信息

作者首先研究了等仿射几何与贝叶斯统计学之间的关系,这里贝叶斯统计学的先验分布被看作统计流形上的体积形式,然后利用统计流形上α平行先验估计和体积形式的关系,结合子流形上的基本方程和基本公式给出了一个统计子流形上具有等仿射结构的条件.

关键词：流计流形等仿射结构活动标架子流形

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Association Testing for High-Dimensional Multiple Response Regression

引用

系统科学与复杂性学报:英文版 2023年第4期36卷 1680-1696页

作者： WANG jinjuan JIANG Zhenzhen LIU hongzhi MENG Zhen school of Mathematics and statistics Beijing Institute of TechnologyBeijing 100081China LSC Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China school of Mathematical Science University of Chinese Academy of SciencesBeijing 100190China Institute of Food Science and Technology Chinese Academy of Agricultural Sciences/Comprehensive Key Laboratory of Agricultural Products Processing and Quality ControlMinistry of AgricultureBeijingChina school of statistics Capital University of Economics and BusinessBeijing 100070China

Multiple response regression model is commonly employed to investigate the relationship between multiple outcomes and a set of potential predictors,where single-response analysis and multivariate analysis of variance(MANOVA)are two frequently used methods for association ***,both methods have their own *** basis of the former method is independence of multiple responses and the latter one assumes that multiple responses are normally *** this work,the authors propose a test statistic for multiple response association analysis in high-dimensional situations based on F *** is free of normal distribution assumption and the asymptotic normal distribution is obtained under some regular *** computer simulations and four real data applications show its superiority over single-response analysis and MANOVA methods.

关键词： Association analysis high-dimensional multiple response multiple response regression non normality

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Testing Serial Correlation in Partially Linear Additive Models

引用

Acta Mathematicae Applicatae Sinica 2019年第2期35卷 401-411页

作者： jin yang Chuan-hua WEI school of statistics and Data Science Nankai University Department of Applied Mathematics The Hong Kong Polytechnic University Department of statistics School of ScienceMinzu University of China

As an extension of partially linear models and additive models, partially linear additive model is useful in statistical modelling. This paper proposes an empirical likelihood based approach for testing serial correlation in this semiparametric model. The proposed test method can test not only zero first-order serial correlation, but also higher-order serial correlation. Under the null hypothesis of no serial correlation, the test statistic is shown to follow asymptotically a chi-square distribution. Furthermore, a simulation study is conducted to illustrate the performance of the proposed method.

关键词： Partially linear additive model Backfitting Profile least-squares approach Empirical likelihood Serial correlation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The finite-time ruin probability in the presence of Sarmanov dependent financial and insurance risks

引用

Applied Mathematics(A Journal of Chinese Universities) 2014年第2期29卷 194-204页

作者： yang yang LIN jin-guan TAN Zhong-quan school of Mathematics and statistics Nanjing Audit University school of Economics and Management Southeast University Department of Mathematics Southeast University College of Mathematics Physics and Information Engineering Jiaxing University

Consider a discrete-time insurance risk model. Within period i, i≥ 1, Xi and Yi denote the net insurance loss and the stochastic discount factor of an insurer, respectively. Assume that {（Xi, Yi）, i≥1） form a sequence of independent and identically distributed random vectors following a common bivariate Sarmanov distribution. In the presence of heavy-tailed net insurance losses, an asymptotic formula is derived for the finite-time ruin probability.

关键词： Asymptotics long-tailed and dominatedly-varying-tailed distribution financial and insurancerisks finite-time ruin probability bivariate Sarmanov distribution.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

边限检验理论及几点讨论

引用

统计与信息论坛 2008年第7期23卷 14-19,28页

作者：靳军会邱长溶西安交通大学经济与金融学院陕西西安710061

检验经济变量之间长期关系的协整技术要求变量是同阶单整的,这不可避免地涉及一定程度的预检验问题,而预检验问题会增加变量间长期关系分析的不确定性。当不能确定变量的单整类型时,边限检验理论提出了一个可以直接检验一个变量和一组... 详细信息

检验经济变量之间长期关系的协整技术要求变量是同阶单整的,这不可避免地涉及一定程度的预检验问题,而预检验问题会增加变量间长期关系分析的不确定性。当不能确定变量的单整类型时,边限检验理论提出了一个可以直接检验一个变量和一组解释变量之间长期关系的新方法。在介绍了边限检验方法中基本的VAR模型和假设及边限检验方法中用到的重要统计量——Wald统计量和T统计量及它们各自的渐近分布形式后,说明了边限检验理论在理论和实际运用当中需要注意的几个问题,最后通过实例分析说明了边限检验理论的运用。

关键词：边限检验长期关系渐进分布

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：