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On tail behavior of nonlinear autoregressive functional conditional heteroscedastic model with heavy-tailed innovations

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Science China Mathematics 2005年第9期48卷 1169-1181页

作者： pan Jiazhu wu Guangxu LMAM and School of Mathematical Sciences Peking University Beijing 100871 China LMAM and School of Mathematical Sciences Peking University Beijing 100871 China

We study the tail probability of the stationary distribution of nonparametric nonlinear autoregressive functional conditional heteroscedastic (NARFCH) model with heavytailed innovations. Our result shows that the tail of the stationary marginal distribution of an NARFCH series is heavily dependent on its conditional variance. When the innovations are heavy-tailed, the tail of the stationary marginal distribution of the series will become heavier or thinner than that of its innovations. We give some specific formulas to show how the increment or decrement of tail heaviness depends on the assumption on the conditional variance function. Some examples are given.

关键词： tail probability, stationary distribution, nonlinear AR model, nonlinear autoregressive functional conditional heteroscedastic model, heavy-tailed distribution.

Emerging roles of circular RNAs in stem cells

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Genes & Diseases 2023年第5期10卷 1920-1936页

作者： Mengru Wang Juan wu pan wu Yuhong Li Department of Cell Biology Army Medical UniversityChongqing 400038China

Circular RNAs (circRNAs) are a novel class of noncoding RNAs that widely exist in eukaryotes. As a new focus in the field of molecular regulation, circRNAs have attracted much attention in recent years. Previous studies have confirmed that circRNAs are associated with many physiological and pathological processes. CircRNAs also participate in the regulation of stem cells. Stem cells have the properties of self-renewal and differentiation, which make stem cell therapy popular. CircRNAs may serve as new targets in stem cell therapy due to their regulation in stem cells. However, the underlying relationships between circRNAs and stem cells are still being explored. In this review, we briefly summarize the effects of circRNAs on stem cells, in the context of biological activities, aging and apoptosis, and aberrant changes. Moreover, we also examine the biological roles of stem cell-derived exosomal circRNAs. We believe our review will provide insights into the effects of circRNAs on stem cells.

关键词： Circular RNA Differentiation Proliferation Stem cell Stem cell-derived exosomes

Carbon dioxide partial pressure and its diffusion flux in karst surface aquatic ecosystems:a review

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Acta Geochimica 2023年第5期42卷 943-960页

作者： Xingxing Cao Qixin wu Wanfa Wang pan wu College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and Environment Ministry of EducationGuizhou UniversityGuiyang 550025China

Carbon dioxide(CO_(2))emissions from aquatic ecosystems are an important component of the karst carbon cycle process and also a key indicator for assessing the effect of karst carbon *** paper reviewed the CO_(2)partial pressure(pCO_(2))and its diffusion flux(FCO_(2))in karst surface aquatic ecosystems,mainly rivers,lakes,and reservoirs,and their influencing factors summarized the methods for monitoring CO_(2)emissions in karst aquatic ecosystems and discussed their adaptation conditions in karst *** pCO_(2)and FCO_(2)decreased in the order of rivers>reservoirs>lakes,and the values in karst lakes were eventually significantly lower than those in global *** pCO_(2)and FCO_(2)of karst aquatic ecosystems had patterns of variation with diurnal,seasonal,water depth and hydrological cycles,and spatial and temporal *** sources of CO_(2)in karst waters are influenced by both internal and external sources,and the key spatial and temporal factors affecting the CO_(2)emissions from karst rivers,lakes,and reservoirs were determined in terms of physicochemical indicators,biological factors,and bio-genic elements;additionally,the process of human activity interference on CO_(2)emissions was ***,a conceptual model illustrating the impacts of urban devel-opment,agriculture,mining,and dam construction on the CO_(2)emissions at the karst surface aquatic ecosystem is ***,based on the disadvantages existing in current research,we proposed several important research fields related to CO_(2)emissions from karst surface aquatic ecosystems.

关键词： Karst area River Lake Reservoir Partial pressure of CO_(2) CO_(2)diffusion flux

Mg^(2+) improves biomass production from soybean wastewater using purple non-sulfur bacteria

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Journal of Environmental Sciences 2015年第2期27卷 43-46页

作者： pan wu Guangming Zhang Jianzheng Li State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology School of Environment & Resource Renmin University of China

Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria（PNSB）. This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2＋under the light-anaerobic condition. Results showed that with the optimal Mg2＋dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand（COD） removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2＋could promote the content of bacteriochlorophyll in photosynthesis because Mg2＋is the bacteriochlorophyll active center, and thus improved adenosine triphosphate（ATP） production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials（biomass yield） and COD removal, leading to more biomass production. With 10 mg/L Mg2＋, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.

关键词： Purple non-sulfur bacteria Mg2+ Biomass resource Soybean wastewater Photosynthesis

Chitosan nanoparticles crosslinked by glycidoxypropyltrimethoxysilane for pH triggered release of protein

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Chinese Chemical Letters 2009年第1期20卷 79-83页

作者： Ai wu pan Bei Bei wu Jian Min wu Department of Chemistry Zhejiang University Hangzhou 310027 China Hospital of Zhefiang University Hangzhou 310058 China

pH-responsive-chitosan nanoparticles for the control release of protein drug were prepared by combining two-step crosslinking method, in which chitosan was subsequently crosslinked by sodium tripolyphosphate （TPP） and glycidoxypropyltrimethoxysilane （GPTMS）. Compared with TPP crosslinked chitosan particles, the two-step crosslinked nanoparticles were not only pH-responsive but also more stable in wide pH range. Fluorescein isothiocyanate （FITC） labeled anti-human-IgG antibody was used as a model protein drug for evaluating the control release profile of the nano-carrier. The amount of released antibody increased from 5.6% to 50% when the pH of solution shifted from 7.4 to 6.0. The results suggest the possible application of the nanoparticles as pH- responsive drug delivery materials.

关键词： Chitosan Nanoparticles pH-response Drug delivery Controlled release Protein

Element geochemical characteristics of a soil profile developed on dolostone in central Guizhou, southern China: implications for parent materials

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Acta Geochimica 2016年第4期35卷 445-462页

作者： Xingxing Cao pan wu Zhenxing Cao College of Resource and Environmental Engineering Guizhou University Graduate School of Science and Technology Shizuoka University

This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province(southern China). The chemical weathering characteristics of the studied profile were investigated and the inheritance relationships between the terra rossa and overlying strata were discussed. The results show that there is no remarkable variation in the major elements and weathering indices from the rock–soil interface to the topsoil, indicating that the studied profile was not typical for in situ crustal chemical weathering. The terra rossa were mainly composed of Si O_2, Al_2O_3 and Fe_2O_3. Compared with the insoluble residues and overlying strata, the terra rossa are characterized by an enrichment of Y and Cs and depletion of Ba and Sr. The subsoil shows a notable Ce negative anomaly, characterized by heavy rare earth element enrichment(L/H = 1.55–3.74), whereas the topsoil shows a positive Ce anomaly with light rare earth element enrichment(L/H = 5.93–9.14). According to Laterite-forming capacity estimates, the terra rossa could not have only been formed from acid-insoluble residues from the bedrock; Al_2O_3 versus Fe_2O_3and Nb plotted against Ta show significant positive correlations between the terra rossa and overlying strata. The Eu/Eu* versusGd_N/Yb_Nand ternary diagrams for Sc, Th, Zr, and Ta suggest that the overlying strata could also provide parent materials for the genesis of terra rossa.

关键词： Terra rossa Dolomite Parent materials Guizhou China

A New Comparison Theorem of Multidimensional BSDEs

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Acta Mathematicae Applicatae Sinica 2015年第1期31卷 131-138页

作者： pan-yu wu Zeng-jing CHEN Qilu Securities Institute for Financial Studies Shandong University School of Mathematics Shandong University

In this paper, we first study a property about the generator g of Backward Stochastic Differential Equation （BSDE） when the price of contingent claims can be represented by a multidimensional BSDE in the no-arbitrage financial market. Furthermore, motivated by the behavior of agents in finance market, we introduce a new total order q on Rn and obtain a necessary and sufficient condition for comparison theorem of multidimensional BSDEs under this order. We also give some further results for q

关键词： backward stochastic differential equation comparison theorem viability property

Assessment for soil loss by using a scheme of alterative sub-models based on the RUSLE in a Karst Basin of Southwest China

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Journal of Integrative Agriculture 2017年第2期16卷 377-388页

作者： CHEN Hao Takashi Oguchi wu pan School of Political Science and Public Administration Huaqiao University Quanzhou 362021 P.R. China Department of Natural Environment Studies The University of Tokyo Kashiwa 277-8568 Japan Center for Spatial Information Science The University of Tokyo Kashiwa 277-8568 Japan College of Resources and Environmental Engineering Guizhou University Guiyang 550025 P.R. China

Accurate assessment of soil loss caused by rainfall is essential for natural and agricultural resources management. Soil erosion directly affects the environment and human sustainability. In this work, the empirical and contemporary model of revised universal soil loss equation （RUSLE） was applied for simulating the soil erosion rate in a karst catchment using remote sensing data and geographical information systems. A scheme of alterative sub-models was adopted to calculate the rainfall erosivity （R）, soil erodibility （K）, slope length and steepness （LS）, cover management （C） and conservation practice （P） factors in the geographic information system （GIS） environment. A map showing the potential of soil erosion rate was produced by the RUSLE and it indicated the severe soil erosion in the study area. Six classes of erosion rate are distinguished from the map： 1） minimal, 2） low, 3） medium, 4） high, 5） very high, and 6） extremely high. The RUSLE gave a mean annual erosion rate of 30.24 Mg ha-1 yr-1 from the 1980s to 2000s. The mean annual erosion rate obtained using RUSLE is consistent with the result of previous research based on in situ measurement from 1980 to 2009. The high performance of the RUSLE model indicates the reliability of the sub-models and possibility of applying the RUSLE on quantitative estimation. The result of the RUSLE model is sensitive to the slope steepness, slope length, vegetation factors and digital elevation model （DEM） resolution. The study suggests that attention should be given to the topographic factors and DEM resolution when applying the RUSLE on quantitative estimation of soil loss.

关键词： soil erosion RUSLE GIS Karst Basin

Boosting extraction of Pb in contaminated soil via interfacial solar evaporation of multifunctional sponge

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Green Energy & Environment 2023年第5期8卷 1459-1468页

作者： pan wu Xuan wu Yida Wang Jingyuan Zhao Haolan Xu Gary Owens Future Industries Institute UniSA STEMUniversity of South AustraliaMawson Lakes CampusSA 5095Australia

Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant *** the recent advance in photothermal technology,a functional sponge was prepared by coating a sodium alginate(SA)impregnated sponge with a surface layer of reduced graphene oxide(rGO)to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar *** SA loaded sponge had a Pb adsorption capacity of 107.4 mg g^(-1).Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m^(-2)h^(-1)in soil media under one sun illumination and with a wind velocity of 2 m s^(-1).Over 12 continuous days of indoor evaporation testing,the Pb extraction efficiency was increased by 22.0%under 1 sun illumination relative to that observed without ***,Pb extraction was further improved by 48.9%under outdoor evaporation conditions compared to indoor ***,this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation,which should also be applicable to a variety of other environmental contaminants.

关键词： Photothermal materials Interfacial solar evaporation Reduced graphene oxide Pb extraction Soil remediation