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persistence of Organic Pesticide HCH in Waters

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Meteorological and Environmental Research 2014年第3期5卷 42-45页

作者： Yang Dongfang Zhu Sixi Wang Fengyou Wang Yi Yang Xiuqin Research Center for Karst Wetland Ecology Guizhou Minzu University College of Chemistry and Environmental Science Guizhou Minzu University North China Sea Environmental Monitoring Center State Oceanic Administration

[Objective]The research aimed to study HCH persistence in Jiaozhou Bay.[Method]Based on the investigation data in Jiaozhou Bay in April,August,September and October of 1989,we analyzed the source,distribution and migration status of HCH in sea area of Jiaozhou Bay.By using structural model of HCH environmental background value in Jiaozhou Bay,basic background value,input amount of terrestrial runoff and environmental background value of HCH in Jiaozhou Bay were calculated.[Result]Basic background value of HCH in water area of Jiaozhou Bay was 0.012 7μg/L,HCH input amount of terrestrial runoff was during 0-0.057 1μg/L,HCH content input by ocean current was 0μg/L.Then,environmental background value of HCH in water area of Jiaozhou Bay was during 0.012 7-0.069 8μg/L.[Conclusion]HCH needed long time migrating from land to sea bottom,and experienced terrestrial migration process,water migration process,settlement process and biological migration cycle process.In these migration processes,HCH was persistent,and always caused threats and harms on organism.

关键词： HCH persistence Environmental background value Biological migration cycle Jiaozhou Bay China

persistence of Anti-SARS-CoV-2 IgM Antibody up to 8 Months Post-COVID-19

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Case Reports in Clinical Medicine 2021年第9期10卷 227-231页

作者： Carlos David A. Bichara Ednelza S. G. Amoras Gergiane L. Vaz Cléa N. C. Bichara Isabella P. C. Amaral Amaral Antonio C. R. Vallinoto Laboratório de Virologia Instituto de Ciências Biológicas Universidade Federal do Pará (UFPA) Belém Brasil Amaral Costa Medicina Diagnóstica Belém Brasil Faculdade de Medicina Centro de Ciências Biológicas e da Saúde Universidade do Estado do Pará (UEPA) Belém Brasil Programa de Pós-Graduaç ã o em Biologia de Agentes Infecciosos e Parasitários Instituto de Ciências Biológicas Universidade Federal do Pará (UFPA) Belém Brasil

Here, we present a longitudinal analysis of two patients who recovered from COVID-19 more than 8 months prior but showed persistent serological detection of anti-SARS-CoV-2 IgM. We still do not know the exact reason for this prolonged persistence of IgM in these patients. To our knowledge, these are the first reports of IgM persistence in the context of SARS-CoV-2 infection and point to the need for no longer using IgM as a diagnostic criterion for acute or recent COVID-19. One should opt for gold standard molecular methodologies due to their high sensitivity and specificity.

关键词： COVID-19 SARS-CoV-2 Antibodies IgM persistence

Sorption and desorption behavior of residual antidepressants and caffeine in freshwater sediment and sewage sludge

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International Journal of Sediment Research 2022年第3期37卷 346-354页

作者： Ismael Laurindo Costa Junior Christiane Schinneider Machado Adelmo Lowe Pletsch Yohandra Reyes Torres Department of Chemistry Federal University of Technology-Paraná (UTFPR) Department of Chemistry State University of Midwest (UNICENTRO)

The use of antidepressants is widespread in modern times. Thus, they present a potential risk for ecosystems due to occurrence in domestic sewage containing unaltered metabolites and structures, even after the treatment plants have processed the sewage. The current research investigated the sorption and desorption of antidepressants(citalopram, venlafaxine, fluoxetine, sertraline, and amitriptyline) and caffeine from freshwater sediment and sewage sludge. The samples of freshwater sediment were collected in a river spring in an area with few anthropogenic sources of pollution and samples of sewage sludge were taken from stabilization ponds of a sewage treatment. The matrices were mainly composed of organic fractions, sediment of humic nature, and aliphatic biomolecules in sludges. The presence of silt and clay in the sediment proved to be important for the sorption process when compared to the flocs and colloidal structure of the sludge. The kinetic study indicated pseudo-first order behavior. The Freundlich isotherm was satisfactorily used in the interpretation of sorption and desorption for all analytes and matrices. The high percentages obtained for desorption suggest analyte mobility, which is more intense in the sludge than in the sediment since each matrix has a different composition. It can be considered that the information obtained here reinforces the ecotoxicological concern with respect to pharmacological residues in the environment, as processes of retention by sorption in the sludge and the sediment have been confirmed, as well as the preferential partition of some analytes by the aqueous phase.

关键词： Emerging pollutants Drugs persistence Partition Mobility Sorption

A regime-switching stochastic SIR epidemic model with a saturated incidence and limited medical resources

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生物数学学报:英文版 2023年第7期16卷 91-110页

作者： Wei Wei Wei Xu Jiankang Liu Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 ShaanciP.R.China

The stochastic switching SIR epidemic model with saturated incidence and limited medical treatment is investigated in this paper.By using Lyapunov methods and Ito formula,we first prove that the system has a unique global positive solution with any positive initial value.Then combining inequality technique and the ergodic property of Markov switching,the suficient conditions for extinction and persistence in the mean of the disease are established.The results demonstrate that increasing medical resources and improving supply efficiency can accelerate the transition from the persistent state to the extinct state.Meanwhile,the high incidence rate will slow down the extinction of the disease.Specially,the switching noise can induce the system to toggle between the extinct and persistent states.Finally,some numerical simulations are carried out to confirm the analytical results.

关键词： Epidemic model extinction persistence Markov switching saturated incidence

Threshold dynamics of a cooperation-diffusion-advection model in open advective environments

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International Journal of Biomathematics 2023年第4期16卷 209-227页

作者： Qinglan Liu Guohong Zhang Xiaoli Wang School of Mathematics and Statistics Southwest University Chongqing 400715P.R.China

This paper is concerned with a Lotka-Volterra cooperation-reaction-diffusion-advection model in open advective environments.It is found that there are two critical advection rates,which classify the dynamic behavior of this system into three different scenarios,namely,(i)both species go extinct;(ii)one species survives in the long run,the other goes extinct and(ii)both species can persistently survive.The theoretical results provide some interesting highlights in ecological protection in streams and rivers.

关键词： Cooperation-diffusion-advection open advective environments persistence extinction threshold dynamics

Extreme parameter sensitivity of transient persistence in spatially coupled ecological systems

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Theoretical & Applied Mechanics Letters 2011年第6期1卷 51-56页

作者： Lin Du, Wei Xu,) and Zhanguo Li Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710072, China Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 China

This paper investigates persistence of transient dynamics depending on parameters in spatially coupled ecological systems. We emphasis that the persistence time can be obtained by populations of species or Lyapunov exponents of transient dynamics. It is found that extreme sensitive dependence of persistence on parameters occurs commonly in ecological models. A non-zero uncertainty exponent is used to characterize the high sensitivity in a reasonable parameter region. The result of a small uncertainty exponent indicates a fractal structure of transient persistence in the two-dimensional parameter space. In spite of different methods of measurement, the fractal dimensions have a good consistency. Since populations of natural communities with many coupled oscillators are often affected by disturbance of migration rates, the large probability of error in estimating persistence of transients should be concerned.

关键词： transient dynamics predator-prey systems persistence sensitivity uncertainty exponents fractal dimensions

BOUNDEDNESS, persistence　AND　ASYMPTOTIC SATBILITY ON　 THE　 DELAY　DIFFERENCE　 EQUATION　 x——(n+1) = f(x_n, x_(n-1),…, x_(n-k))

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Annals of Differential Equations 1999年第1期15卷 38-47页

作者：欧春华唐衡生罗蔚

In this paper we investigate the boundedness, persistence and asymptoticbehavior of the positive solution of the equation xn+1 = f(xn , xn- 1,… , xn-k)and its special cases.

关键词： differcnce equation persistence asymptotic stabilityAMS Subject Classification 39A10

INFLUENCE OF SOIL MOISTURE AND VEGETATION ON CLIMATE (Ⅰ)——THEORETICAL ANALYSIS TO persistence OF SHORT-TERM CLIMATE ANOMALIES

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Science China Chemistry 1992年第12期35卷 1485-1493页

作者：刘永强叶笃正季劲钧 Institute of Atmospheric Physics Academia Sinica Beijing 100080 PRC

Influence of soil moisture and vegetation on persistence of short-term climate anomalies isanalyzed theoretically through a heat and water balance model in coupled air-land system.It is shown that the soil hydrologic condition, rather than the soil thermal situation, is adominant factor in maintenance of climatic anomalies. The persistence of climate anomaliesis dependent largely on the capacity of water and heat exchange on the land surface. The cli-mate anomalies would persist longer for less soil moisture or vegetation cover. Furthermore,compared with humid areas, the climate anomalies persist longer in an arid climate envi-ronment.

关键词： soil moisture vegetation persistence of climate anomalies theoretical analysis

Influence of Soil Moisture and Vegetation on Climate (Ⅱ)——Numerical Experiments on persistence of Short-term Climatic Anomalies

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Science China Chemistry 1993年第1期36卷 102-109页

作者：刘永强叶笃正季劲钧 Institute of Atmospheric Physics Academia Sinica Beijing 100080 PRC

Numerical experiments on the influence of soil moisture and vegetation on the persistence of short-term climatic anomalies are performed with a vertical one-dimensional climate model in the atmosphere-soil-vegetation system.The experimental results indicate that, as shown by theoretical analysis in Part Ⅰ of this paper,soil hydrology is crucially important for maintenance of short-term climatic anomalies over land areas. Possible physical process concerned with impact of soil moisture and vegetation on the persistence is further discussed.

关键词： soil moisture vegetation persistence of climatic anomalies numerical experiments.