检索结果-南通市图书馆

Hypothesis Testing with Paired Partly Interval Censored Data

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2019年第3期35卷 541-548页

作者： Ding-jiao CAI Bo LU xing-wei tong School of Mathematics and Information Science Henan University of Economics and LawZhengzhou 450046China Division of Biostatistics College of Public HealthOhio State UniversityColumbusOhio43210U.S.A School of Statistics Beijing Normal UniversityBeijing 100875China

Partly interval censored data frequently occur in many areas including clinical trials,epidemiology research,and medical follow-up *** data come from observational studies,we need to carefully adjust for the confounding bias in order to estimate the true treatment *** matching designs are popular for removing confounding bias without parametric *** time-to-event outcomes,there are some literature for hypothesis testing with paired right censored data,but not for interval censored data.O’Brien and Fleming extended the Prentice Wilcoxon test to right censored paired data by making use of the PrenticeWilcoxon *** proposed the Akritas test and established its asymptotic *** extend Akritas test to partly interval censored *** estimate the survival distribution function by nonparametric maximum likelihood estimation(NPMLE),and prove the asymptotic validity of the new *** improve our test under small sample size or extreme distributions,we also propose a modified version using the rank of the score *** results indicate that our proposed methods have very good performance.

关键词： partly interval censored data nonparametric maximum likelihood estimation Wilcoxon signed rank test

A Scoring Criterion For Learning Chain Graphs

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2006年第4期22卷 1063-1068页

作者： Zhong Guo ZHENG Jing XU xing wei tong wDepartment of Mathematical Sciences Peking University Beijing 100871 P. R. China Department of Mathematics Beijing Normal University Beijing 100875 P. R. China

A chain graph allows both directed and undirected edges, and contains the underlying mathematical properties of the two. An important method of learning graphical models is to use scoring criteria to measure how well the graph structures fit the data. In this paper, we present a scoring criterion for learning chain graphs based on the Kullback Leibler distance. It is score equivalent, that is, equivalent chain graphs obtain the same score, so it can be used to perform model selection and model averaging.

关键词： Chain graph Markov equivalence Scoring criterion

Efficient Estimation for Semiparametric Varying-Coefficient Partially Linear Regression Models with Current Status Data

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2009年第2期25卷 195-204页

作者： Tao Hu Heng-jian Cui xing-wei tong School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education Beijing 100875 China

This article considers a semiparametric varying-coefficient partially linear regression model with current status data. The semiparametric varying-coefficient partially linear regression model which is a generalization of the partially linear regression model and varying-coefficient regression model that allows one to explore the possibly nonlinear effect of a certain covariate on the response variable. A Sieve maximum likelihood estimation method is proposed and the asymptotic properties of the proposed estimators are discussed. Under some mild conditions, the estimators are shown to be strongly consistent. The convergence rate of the estimator for the unknown smooth function is obtained and the estimator for the unknown parameter is shown to be asymptotically efficient and normally distributed. Simulation studies are conducted to examine the small-sample properties of the proposed estimates and a real dataset is used to illustrate our approach.

关键词： Partly linear model varying-coefficient current status data asymptotically efficient estimator sieve MLE

Learning Causal Effect Using Machine Learning with Application to China's Typhoon

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2020年第3期36卷 702-713页

作者： Peng WU Qi-rui HU xing-wei tong Min WU School of Statistics Beijing Normal UniversityBeijing 100875China School of mathematics and Statistics Hubei University of Science and TechnologyHubei 437000China

Matching is a routinely used technique to balance covariates and thereby alleviate confounding bias in causal inference with observational *** of the matching literatures involve the estimating of propensity score with parametric model,which heavily depends on the model *** this paper,we employ machine learning and matching techniques to learn the average causal *** comparing a variety of machine learning methods in terms of propensity score under extensive scenarios,we find that the ensemble methods,especially generalized random forests,perform favorably with *** apply all the methods to the data of tropical storms that occurred on the mainland of China since 1949.

关键词： causal effect matching machine learning

Causal Analysis of Futures Sugar Prices in Zhengzhou

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2012年第1期28卷 39-48页

作者： Fang WANG xing-wei tong Jing XU Jian-ping CHEN School of Mathematical Science Beijing Normal UniversityBeijing 100875China School of Information Technology and Management Engineering University of International Business and EconomicsBeijing 100029China China International Science and Technology Convention Center No.12 Yumin RoadChaoyang DistrictBeijing 100029China

In this paper, we are interested in investigating the causal relationships among futures sugar prices in the Zhengzhou futures exchange market （ZF）, the spot sugar prices in Zhengzhou （ZS） and the futures sugar prices in New York futures exchange market （NF）. A useful tool called Bayesian network is introduced to analyze the problem. Since there are only three variables in our Bayesian network, the algorithm is straightforward： we display all the 25 possible network structures and adopt certain scoring metrics to evaluate them. We applied five different scoring metrics in total. Firstly, for each metric, we obtained 24 scores, each calculated from one of the 24 possible structures i.e. a Directed Acyclic Graph （DAG）. Then we eliminated the network structure which represents the independence of the three variables according to our prior knowledge concerning the futures sugar market. After that, the optimal network structure which implies the causal relationships was selected according to the corresponding scoring metric. Finally, after comparing the results from different scoring metrics, we obtained the relatively affirmative conclusion that ZS causes ZF from both the Bayesian Dirichlet （BD） metric, Bayesian Dirichlet-Akaike Information Criterion （BD-AIC） metric, Bayesian Dirichlet-Bayesian Information Criterion （BD-BIC） metric and Bayesian Information Criterion （BIC） metric. The conclusions that NF causes ZF and ZF causes ZS from the Akaike Information Criterion （AIC） metric and ZF causes ZS from the BIC metric were useful and significant to our investigation.

关键词： causal relationship Bayesian network BD metric AIC metric BIC metric

Learning Dynamic Causal Relationships Among Sugar Prices

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2017年第3期33卷 809-818页

作者： Jing XU xing-wei tong Fang WANG Jian-ping CHEN School of Statistics University of International Business and EconomicsBeijing 100029China School of Statistics Beijing Normal UniversityBeijing 100875China COFCO Tunhe Co. LtdUrumqiXinjiang 830000China

In this paper, we are interested in exploring the dynamic causal relationships among two sets of three variables in different quarters. One set is futures sugar closing price in Zhengzhou futures exchange market （ZC）, spot sugar price in Zhengzhou （ZS） and futures sugar closing price in New York futures exchange market（NC） and the other includes futures sugar opening price in Zhengzhou （ZO）, ZS and NC. For each quarter, we first use Bayesian model selection to obtain the optimal causal graph with the highest BD scores and then use Bayesian model averaging approach to explore the causal relationship between every two variables. From the real data analysis, the two conclusions almost coincide, which shows that the two methods are practical.

关键词： Bayesian Network dynamic causal relationships Bayesian model selection Bayesian model averaging

Semiparametric Analysis of Longitudinal Data with Informative Observation Times

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2011年第1期27卷 29-42页

作者： Liu-quan Sun Xiao-yun Mu Zhi-hua Sun xing-wei tong Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of mathematical Sciences Beijing Normal University Beijing 100875 China

In many longitudinal studies, observation times as well as censoring times may be correlated with longitudinal responses. This paper considers a multiplicative random effects model for the longitudinal response where these correlations may exist and a joint modeling approach is proposed via a shared latent variable. For inference about regression parameters, estimating equation approaches are developed and asymptotic properties of the proposed estimators are established. The finite sample behavior of the methods is examined through simulation studies and an application to a data set from a bladder cancer study is provided for illustration.

关键词： Estimating equations Informative observation times Joint modeling Latent variables,Longitudinal data

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 587-597页

作者： tong Li Hui-Min xing Hai-Dong Qian Qiao Gao Sheng-Lan Xu Hua Ma Zai-Long Chi State Key Laboratory of Ophthalmology Optometry and Visual ScienceEye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina National Clinical Research Center for Ocular Diseases Eye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina

Several studies have found that transplantation of neural progenitor cells(NPCs)promotes the survival of injured ***,a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical *** extracellular vesicles(sEVs)contain bioactive molecules for neuronal protection and *** studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye *** this study,we intravitreally transplanted sEVs derived from human induced pluripotent stem cells(hiPSCs)and hiPSCs-differentiated NPCs(hiPSC-NPC)in a mouse model of optic nerve *** results show that these intravitreally injected sEVs were ingested by retinal cells,especially those localized in the ganglion cell *** with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration,and regulated the retinal microenvironment by inhibiting excessive activation of *** analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells,which had protective effects on RGCs after optic nerve *** findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

关键词： exosome miRNA neural progenitor cell neurodegeneration neuroinflammation neuroprotection optic nerve crush optic neuropathy retinal ganglion cell small extracellular vesicles

Targeting Epac2 and GluA3-containing AMPARs:a novel therapeutic strategy for Alzheimer's disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第11期20卷 3223-3224页

作者： tong Zhang Martina Schmidt Department of Molecular Pharmacology Groningen Research Institute of PharmacyUniversity of GroningenGroningenThe Netherlands School of Pharmacy Tianjin Medical UniversityTianjinChina

Alzheimer's disease(AD)is a neurodegenerative disease that manifests progressive decline in memory and *** the early stage of AD,memory retrieval is impaired preceding memory acquisition and consolidation(Roy et al.,2016).Prior to the onset of symptoms,pathological amyloid-β(Aβ)plagues and tau protein tangles accumulate in extracellular and intracellular spaces,respectively,leading to *** these hallmark pathologies,Aβ is proposed to be the primary etiology by triggering a cascade of pathogenic events,including neuroinflammation,oxidative stress,tau hyperphosphorylation,synaptic/neuronal dysfunction,and neuronal death(Zhang et al.,2023b).

关键词： Alzheimer impaired Aβ