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  1. Article ; Online: Exploring the effect of ecological land structure on PM2.5

    Yang Wang / Min Wang / Yingmei Wu / Guiquan Sun

    Environment International, Vol 174, Iss , Pp 107889- (2023)

    A panel data study based on 277 prefecture-level cities in China

    2023  

    Abstract: In the context of serious urban air pollution and limited land resources, it is important to understand the environmental value of ecological land. Previous studies focused mostly on the effectiveness of a particular type of green space or the total ... ...

    Abstract In the context of serious urban air pollution and limited land resources, it is important to understand the environmental value of ecological land. Previous studies focused mostly on the effectiveness of a particular type of green space or the total amount of ecological land on PM2.5 and have rarely analyzed the association between ecological land structure and PM2.5 systematically and quantitatively. Therefore, we took 277 cities in China as an example, comprehensively compared the results of different models, and selected a spatial Durbin model using time-fixed effects to dissect the degree of influence of ecological land and different land types within it on PM2.5. The urban ecological land use structure was closely related to PM2.5, and the higher the proportion of ecological land use was, the lower the PM2.5. The degree and direction of influence of different types of land functions within ecological land on PM2.5 differed, with forests, shrubs, and grasslands causing a weakening impact on PM2.5, while wetlands and waters did not have a weakening role. The degree of reduction of PM2.5 by a single type of ecological land was significantly smaller than that by a composite type of ecological land. Green space should be comprehensively considered, designed and adjusted in urban planning to continuously optimize the ecological spatial structure, increase landscape diversity and maximize ecological benefits. The findings of this study help with exploring the effects of land use structure under the goal-oriented control of air pollution and provide theoretical reference and decision-making support for formulating precise air pollution control policies and optimizing the spatial development of national land.
    Keywords Ecological land structure ; PM2.5 ; Ecological effects ; Air pollution ; Spatial Durbin model ; Environmental sciences ; GE1-350
    Subject code 710 ; 910
    Language English
    Publishing date 2023-04-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Data-Driven Artificial Intelligence Model of Meteorological Elements Influence on Vegetation Coverage in North China

    Huimin Bai / Zhiqiang Gong / Guiquan Sun / Li Li

    Remote Sensing, Vol 14, Iss 1307, p

    2022  Volume 1307

    Abstract: Based on remote sensing data of vegetation coverage, observation data of basic meteorological elements, and support vector machine (SVM) method, this study develops an analysis model of meteorological elements influence on vegetation coverage (MEVC). The ...

    Abstract Based on remote sensing data of vegetation coverage, observation data of basic meteorological elements, and support vector machine (SVM) method, this study develops an analysis model of meteorological elements influence on vegetation coverage (MEVC). The variations for the vegetation coverage changes are identified utilizing five meteorological elements (temperature, precipitation, relative humidity, sunshine hour, and ground temperature) in the SVM model. The performance of the SVM model is also evaluated on simulating vegetation coverage anomaly change by comparing with statistical model multiple linear regression (MLR) and partial least squares (PLS)-based models. The symbol agreement rates (SAR) of simulations produced by MLR, PLS, and SVM models are 55%, 57%, and 66%, respectively. The SVM model shows obviously better performance than PLS and MLR models in simulating meteorological elements-related interannual variation of vegetation coverage in North China. Therefore, the introduction of the intelligent analysis method in term of SVM in model development has certain advantages in studying the internal impact of meteorological elements on regional vegetation coverage. It can also be further applied to predict the future vegetation anomaly change.
    Keywords support vector machine ; meteorological element ; vegetation coverage ; machine learning ; model ; Science ; Q
    Subject code 910
    Language English
    Publishing date 2022-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Analysis of a multi patch dynamical model about cattle brucellosis

    Juan Zhang / Shigui Ruan / Guiquan Sun / Xiangdong Sun / Zhen Jin

    Journal of Shanghai Normal University (Natural Sciences), Vol 43, Iss 5, Pp 441-

    2014  Volume 455

    Abstract: The dissemination of cattle brucellosis in Zhejiang province of China can be attributed to the transport of cattle between cities within the province． In this paper，an n-patch dynamical model is proposed to study the effect of cattle dispersal on ... ...

    Abstract The dissemination of cattle brucellosis in Zhejiang province of China can be attributed to the transport of cattle between cities within the province． In this paper，an n-patch dynamical model is proposed to study the effect of cattle dispersal on brucellosis spread． Theoretically，we analyze the dynamical behavior of the muti-patch model． For the 2-patch submodel，sensitivity analyses of the basic reproduction number Ｒ0 and the number of the infectious cattle in term of model parameters are carried out． By numerical analysis，it is obtained that the dispersal of susceptible cattle between patches and the centralization of infected cattle to the large scale patch can alleviate the epidemic and are in favor of the control of disease in the whole region．
    Keywords brucellosis; cattle; n-patch model; dispersal ; Science (General) ; Q1-390
    Language Chinese
    Publishing date 2014-10-01T00:00:00Z
    Publisher Academic Journals Center of Shanghai Normal University
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Analysis of a multi patch dynamical model about cattle brucellosis

    Juan Zhang / Shigui Ruan / Guiquan Sun / Xiangdong Sun / Zhen Jin

    Journal of Shanghai Normal University (Natural Sciences), Vol 43, Iss 5, Pp 441-

    2014  Volume 455

    Abstract: The dissemination of cattle brucellosis in Zhejiang province of China can be attributed to the transport of cattle between cities within the province. In this paper,an n-patch dynamical model is proposed to study the effect of cattle dispersal on ... ...

    Abstract The dissemination of cattle brucellosis in Zhejiang province of China can be attributed to the transport of cattle between cities within the province. In this paper,an n-patch dynamical model is proposed to study the effect of cattle dispersal on brucellosis spread. Theoretically, we analyze the dynamical behavior of the muti-patch model. For the 2-patch submodel, sensitivity analyses of the basic reproduction number R 0 and the number of the infectious cattle in term of model parameters are carried out. By numerical analysis, it is obtained that the dispersal of susceptible cattle between patches and the centralization of infected cattle to the large scale patch can alleviate the epidemic and are in favor of the control of disease in the whole region.
    Keywords brucellosis ; cattle ; n -patch model ; dispersal ; Science (General) ; Q1-390
    Language English
    Publishing date 2014-10-01T00:00:00Z
    Publisher Academic Journals Center of Shanghai Normal University
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Stability Analysis of an HIV/AIDS Dynamics Model with Drug Resistance

    Qianqian Li / Shengshan Cao / Xiao Chen / Guiquan Sun / Yunxi Liu / Zhongwei Jia

    Discrete Dynamics in Nature and Society, Vol

    2012  Volume 2012

    Abstract: A mathematical model of HIV/AIDS transmission incorporating treatment and drug resistance was built in this study. We firstly calculated the threshold value of the basic reproductive number (R0) by the next generation matrix and then analyzed stability ... ...

    Abstract A mathematical model of HIV/AIDS transmission incorporating treatment and drug resistance was built in this study. We firstly calculated the threshold value of the basic reproductive number (R0) by the next generation matrix and then analyzed stability of two equilibriums by constructing Lyapunov function. When R0<1, the system was globally asymptotically stable and converged to the disease-free equilibrium. Otherwise, the system had a unique endemic equilibrium which was also globally asymptotically stable. While an antiretroviral drug tried to reduce the infection rate and prolong the patients’ survival, drug resistance was neutralizing the effects of treatment in fact.
    Keywords Mathematics ; QA1-939 ; Social sciences (General) ; H1-99
    Language English
    Publishing date 2012-01-01T00:00:00Z
    Publisher Hindawi Publishing Corporation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Modeling Transmission of Tuberculosis with MDR and Undetected Cases

    Yongqi Liu / Zhendong Sun / Guiquan Sun / Qiu Zhong / Li Jiang / Lin Zhou / Yupeng Qiao / Zhongwei Jia

    Discrete Dynamics in Nature and Society, Vol

    2011  Volume 2011

    Keywords Social sciences (General) ; H1-99 ; Social Sciences ; H ; DOAJ:Social Sciences ; Mathematics ; QA1-939 ; Science ; Q ; DOAJ:Mathematics ; DOAJ:Mathematics and Statistics
    Language English
    Publishing date 2011-01-01T00:00:00Z
    Publisher Hindawi Publishing Corporation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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