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Empirical likelihood-based inference in a partially linear model for longitudinal data

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Science china Mathematics 2008年第1期51卷 115-130页

作者： xue liugen~(1+) & zhu lixing~2 1 college of applied sciences, beijing university of technology, beijing 100022, china 2 Department of Mathematics, Hong Kong Baptist university, Hong Kong, china college of applied sciences Beijing University of Technology Beijing 100022 China Department of Mathematics Hong Kong Baptist University Hong Kong China

A partially linear model with longitudinal data is considered, empirical likelihood to infer- ence for the regression coefficients and the baseline function is investigated, the empirical log-likelihood ratios is proven to be asymptotically chi-squared, and the corresponding confidence regions for the pa- rameters of interest are then constructed. Also by the empirical likelihood ratio functions, we can obtain the maximum empirical likelihood estimates of the regression coefficients and the baseline function, and prove the asymptotic normality. The numerical results are conducted to compare the performance of the empirical likelihood and the normal approximation-based method, and a real example is analysed.

关键词： partially linear model empirical likelihood confidence region longitudinal data 62G05 62G15 62G20

Cu(Ⅱ) Potentiation of Alzheimer Aβ1-40 Cytotoxicity and Transition on its Secondary Structure

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Acta Biochimica et Biophysica Sinica 2006年第11期38卷 765-772页

作者： xue-Ling DAI~1 Ya-Xuan SUN~2 Zhao-Feng JIANG~2* 1 college of Life Science,Capital Normal university,beijing 100037,china 2 college of applied sciences and Humanities,beijing Union university,beijing 100083,china college of Life Science Capital Normal UniversityBeijing 100037 China college of applied sciences and Humanities Beijing Union UniversityBeijing 100083 China

Mounting evidence has shown that dyshomeostasis of the redox-active biometals such as Cuand Fe can lead to oxidative stress,which plays a key role in the neuropathology of Alzheimer's disease（AD）.Here we demonstrate that with the formation of Cu（Ⅱ）·Aβ1-40 complexes,copper markedly potentiatesthe neurotoxicity exhibited by β-amyloid peptide （Aβ）.A greater amount of hydrogen peroxide was releasedwhen Cu（Ⅱ）·Aβ1-40 complexes was added to the xanthine oxidase/xanthine system detected by potassiumiodide *** bound to Aβ1-40 was observed by electron paramagnetic resonance（EPR） *** dichroism （CD） studies indicated that copper chelation could cause a structuraltransition of Aβ.The addition of copper to Aβ introduced an increase on β-sheet as well as α-helix,whichmay be responsible for the aggregation of Aβ.We hypothesized that Aβ aggregation induced by copper maybe responsible for local injury in *** interaction between Cu2+and Aβ also provides a possible mechanismfor the enrichment of metal ions in amyloid plaques in the AD brain.

关键词： Alzheimer’s disease Cu(Ⅱ)·Aβ1-40 complex neuron injury Aβ secondary structure

ASYMPTOTIC PROPERTIES OF ESTIMATORS IN PARTIALLY LINEAR SINGLE-INDEX MODEL FOR LONGITUDINAL DATA

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Acta Mathematica Scientia 2010年第3期30卷 677-687页

作者：田萍杨林薛留根 Department of Mathematics Xuchang University college of applied sciences Beijing University of Technology

In this article, a partially linear single-index model /or longitudinal data is investigated. The generalized penalized spline least squares estimates of the unknown parameters are suggested. All parameters can be estimated simultaneously by the proposed method while the feature of longitudinal data is considered. The existence, strong consistency and asymptotic normality of the estimators are proved under suitable conditions. A simulation study is conducted to investigate the finite sample performance of the proposed method. Our approach can also be used to study the pure single-index model for longitudinal data.

关键词： Longitudinal data partially linear single-index model penalized spline strong consistency asymptotic normality

Synergistic governance:china's roadmap to improved health through climate and clean air actions

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Environmental Science and Ecotechnology 2024年第4期20卷 14-15页

作者： Tao xue Tong zhu Institute of Reproductive and Child Health National Health Commission Key Laboratory of Reproductive Health and Department of Epidemiology and BiostatisticsMinistry of Education Key Laboratory of Epidemiology of Major Diseases(PKU)School of Public HealthPeking University Health Science CentreBeijingChina SKL-ESPC and SEPKL-AERM College of Environmental Sciences and EngineeringCenter for Environment and HealthPeking UniversityBeijing100871China

The COP28's inaugural Health Day highlighted the growing recognition of the connection between climate and health,while china's State Council released its third air quality action plan aiming at ongoing health *** Synergetic Roadmap project[1],which aims to track china's progress towards carbon neutrality and clean air,provides valuable insights to answer a set of intriguing questions concerning environmental health determinants,their source sectors,and the methods for harmonizing disparate actions to maximize health gain.

关键词： concerning neutral clean

Adjoint method for the optimum planning of industrial pollutant sources

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Science china Earth sciences 2005年第8期48卷 1270-1279页

作者： LIU Feng1,2, HU Fei2 & zhu Jiang2 1. college of Environmental sciences, Peking university, beijing 100871, china 2. LAPC, Institute of Atmospheric Physics, Chinese Academy of sciences, beijing 100029, china 1. college of Environmental sciences Peking University 100871 Beijing China 2. LAPC Institute of Atmospheric Physics Chinese Academy of Sciences 100029 Beijing China

The optimum planning of industrial pollutant sources, which optimizes the economic object without violating environmental constraints, is an important and hard task to be conquered. In this paper, an adjoint method is developed to solve the problem. The penalty function is in-troduced to deal with the environmental inequality constraints, and Lagrange function is con-structed to derive the adjoint equation and the gradient of the object function. In this means, the gradient of the object function can be calculated by solving the adjoint equation, and the infor-mation from the gradient is used to make the object function descend and approach to an optimal solution after some iterations. A two-dimensional, simplified model is used for numerical experi-ments. The theoretical derivations are verified by the results of the experiments. Furthermore, the adjoint method is shown to be of excellent convergence and efficiency, which is adaptive to the fast development of air quality numerical models and super computers.

关键词： optimum planning, industrial pollutant sources, adjoint equation, penalty function, gradient.

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

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Science china(Physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2, DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, xue Qikun1 & ZHANG Ze2, 4 1. State Key Laboratory for Surface Physics, Institute of Physics, Chinese Academy of sciences, beijing 100080, china 2. Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of sciences, beijing 100080, china 3. college of Physics and Engineering, Qufu Normal university, Qufu 273165, china 4. beijing university of technology, beijing 100022, china 1. State Key Laboratory for Surface Physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 2. college of Physics and Engineering Qufu Normal University 273165 Qufu China 3. Laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences 100080 Beijing China 4. beijing university of technology 100022 Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Size-dependent hydroxyl radicals generation induced by SiO_2 ultra-fine particles: The role of surface iron

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Science china Chemistry 2009年第7期52卷 1033-1041页

作者： SHANG Yu1, zhu Tong1, LI Yi1,2 & ZHAO JinCai3 1 college of Environmental sciences and Engineering, Peking university, beijing 100871, china 2 Chinese Academy of Meteorological sciences, beijing 100871, china 3 Institute of Chemistry, Chinese Academy of sciences, beijing 100871, china 1. college of Environmental sciences and Engineering Peking University Beijing 100871 China 2. Chinese Academy of Meteorological sciences Beijing 100871 China 3. Institute of Chemistry Chinese Academy of Sciences Beijing 100871 China

Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM10). The ultra-fine fraction of PM10 has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 14, 100, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 14 nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.812, p1). Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

关键词： ultra-fine particles nano-particles ·OH oxidative stress size-effect

3D building modeling,organization and application in digital city system

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中国科学：技术科学英文版 2010年第S1期53卷 134-142页

作者： YANG xue 1,WENG JingNong 1,2,XIA YuBin 2,WU Lun 3 & SUI ZhengWei 3 1 college of Software,Beihang university,beijing 100191,china 2 college of Computer,Beihang university,beijing 100191,china 3 Institute of Remote Sensing and GIS,Peking university,beijing 100871,china Beihang Univ Coll Software Beijing 100191 Peoples R China Beihang Univ Coll Comp Beijing 100191 Peoples R China Peking Univ Inst Remote Sensing & GIS Beijing 100871 Peoples R China

The real world is a three-dimensional(3D)space requiring that 3D geospatial information applications be developed in alignment with the observer’s visual and perceptive ***,3D building model data are required in a wide range of areas such as urban planning,environmental protection,real estate management and emergency *** the same time,the development of Web service[LU1]technologies allows the possibility of the widely distributed 3D geospatial data on the web.3D city building model with its related information is an important part in the construction of a digital city system,and has become a staple resource on the web *** view of the hierarchical representation of a 3D building model,an abstract of a 3D building model based on structure details is studied,and a novel representation approach named 3D transparent building hierarchical model is presented in this *** approach fully uses both the existing 3D modeling technologies and CAD constructing mapping *** the spatial relationship description,structural components inside a building can be represented and integrated as hierarchical models in a unified 3D *** addition,based on the characteristics of the 3D building model data,a service-oriented architecture and Web service technologies for 3D city building models are *** aim of the approach is that 3D city building models can be used as a kind of data resource service on the web,and can also exist independently in various different web applications.

关键词： 3D modeling 3D transparent building hierarchical models china Star web services

Health-oriented strategies are needed to optimize china’s 2025 clean air action plan

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Science Bulletin 2024年第13期69卷 2007-2008页

作者： Tao xue Ning Kang Wei Wan Tong zhu Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health and Department of Epidemiology and Biostatistics/Ministry of Education Key Laboratory of Epidemiology of Major Diseases(PKU) School of Public HealthPeking University Health Science CentreBeijing 100191China State Environmental Protection Key Laboratory of Atmospheric Exposure and Health Risk Management Center for Environment and HealthPeking UniversityBeijing 100871China Advanced Institute of Information technology Peking UniversityHangzhou 311215China Clean Air Asia Beijing 100600China college of Environmental sciences and Engineering Peking UniversityBeijing 100871China

Recently,china’s State Council issued the Continuous Improvement of Air Quality Action Plan(hereafter,the third action plan),which follows the Air Pollution Prevention and Control Action Plan(2013–2017)(hereafter,the first action plan)and the Three-Year Action Plan for Winning the Blue Sky Defense Battle(2018–2020)(hereafter the second action plan).The first two action plans yielded nationwide health benefits[1–3],from improving lung function[4]to saving medical expenditures[5].Based on our previous estimates[6],due to reductions in the fine particulate matter(PM2.5)level,implementation of the first and second action plans was expected to increase life expectancy by 2.11 and 3.68 months.

关键词： action hereafter nationwide