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SIRS epidemic modeling using fractional-ordered differential equations:Role of fear effect

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International Journal of Biomathematics 2024年第5期17卷 79-100页

作者： Shiv Mangal O.P.Misra Joydip Dhar school of Mathematics and Allied sciences Jiwaji University GwaliorMadhya PradeshIndia Department of Mathematics Post Graduate College BinaMadhya PradeshIndia Department of Applied sciences Atal Bihari Vajpayee-Indian Institute of Information Technology and Management GwaliorMadhya PradeshIndia

In this paper,an SIRS epidemic model using Grunwald-Letnikov fractional-order derivative is formulated with the help of a nonlinear system of fractional differential equations to analyze the effects of fear in the population during the outbreak of deadly infectious *** criteria for the spread or extinction of the disease are derived and discussed on the basis of the basic reproduction *** condition for the existence of Hopf bifurcation is discussed considering fractional order as a bifurcation ***,using the Grunwald-Letnikov approximation,the simulation is carried out to confirm the validity of analytic results *** the real data of COVID-19 in India recorded during the second wave from 15 May 2021 to 15 December 2021,we estimate the model parameters and find that the fractional-order model gives the closer forecast of the disease than the classical *** the analytical results and numerical simulations presented in this study suggest different policies for controlling or eradicating many infectious diseases.

关键词： SIRS epidemic model fear effect Mittag-Leffler function Hopf bifurcation parameter estimation

Interannual evolution of the chemical composition,sources and processes of PM_(2.5)in Chengdu,China:Insights from observations in four winters

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Journal of environmental sciences 2024年第4期138卷 32-45页

作者： Junke Zhang Jiaqi Li Yunfei Su Chunying Chen Luyao Chen Xiaojuan Huang Fangzheng Wang Yawen Huang Gehui Wang Faculty of Geosciences and environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Department of environmental Science&Engineering Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3)Fudan UniversityShanghai 200438China Key Lab of Geographic information Science of the Ministry of Education School of Geographic SciencesEast China Normal UniversityShanghai 200241China

The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also *** studied the interannual variation of PM_(2.5)in Chengdu,one of the most heavily polluted megacities in southwest China,during the most polluted season(winter).Our results show that the mass concentrations of PM_(2.5)decreased significantly year-by-year,from 195.8±91.0μg/m~3in winter 2016 to 96.1±39.3μg/m^(3)in winter *** mass concentrations of organic matter(OM),SO_()4^(2-),NH_(4)^(+)and NO_(3)^(-)decreased by 49.6%,57.1%,49.7% and 28.7%,*** differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO_(3)^(-)and there was a larger contribution from mobile *** contribution of OM and NO_(3)^(-)not only increased with increasing levels of pollution,but also increased year-by-year at the same level of *** sources of PM_(2.5)were identified:combustion sources,vehicular emissions,dust and secondary *** aerosols made the highest contribution and increased year-by-year,from 40.6%in winter 2016 to 46.3% in winter *** contrast,the contribution from combustion sources decreased from 14.4% to 8.7%.Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants(e.g.,OM and NO_(3)^(-))and sources(secondary aerosols and vehicular emissions)in future policies for the reduction of pollution in Chengdu during the winter months.

关键词： PM_(2.5) Chemical composition Sources Interannual evolution Winter Chengdu

Gradient coil design with enhanced shielding constraint for a cryogen-free superconducting MRI system

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Magnetic Resonance Letters 2024年第1期4卷 1-9页

作者： Yaohui Wang Weimin Wang Hui Liu Shunzhong Chen Feng Liu Qiuliang Wang Institute of Electrical Engineering Chinese Academy of SciencesBeijing100190China school of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing100049China school of Electronics&Institute of Biomedical Engineering Peking University&Shenzhen Graduate SchoolShenzhen518055China school of information Technology and Electrical Engineering The University of QueenslandSt LuciaBrisbaneQLD4072Australia

The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI *** this study,we present an enhanced shielding method incorporating a regionalized stray field constraining *** optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by *** real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent *** findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.

关键词： MRI Gradient coil Superconducting magnet Cryogen-free Magnetic shielding

Your personal choices in transportation and food are important for lowering carbon emissions

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Frontiers of environmental Science & Engineering 2024年第6期18卷 27-32页

作者： Bruce Logan Fang Zhang Wulin Yang Le Shi Institute of Energy and the Environment The Pennsylvania State UniversityUniversity ParkPA 16802USA school of Environment Tsinghua UniversityBeijing 100084China College of environmental sciences and Engineering Peking UniversityBeijing 100871China College of environmental and Resource sciences Zhejiang UniversityHangzhou 310058China

There is a global need to reduce greenhouse gas emissions to limit the extent of climate change.A better understanding of how our own activities and lifestyle influence our energy use and carbon emissions can help us enable changes in activities that can lead to reductions in carbon *** we discuss an approach based on examining carbon emissions from the perspective of the unit C,where 1 C is the CO_(2)from food a person would on average eat every *** approach shows that total CO_(2)emissions in China,normalized by the population,is 22.5 C while carbon emissions for a person in the US is 43.9 C.A better appreciation of our own energy use can be obtained by calculating carbon emissions from our own activities in units of C,for example for driving a car gasoline or electric vehicle a certain number of kilometers,using electricity for our homes,and eating different *** this information,we can see how our carbon emissions compare to national averages in different countries and make decisions that could lower our personal CO_(2)emissions.

关键词： Carbon dioxide Climate change Daily energy Greenhouse gas

Study on Quantitative Precipitation Estimation by Polarimetric Radar Using Deep Learning

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Advances in Atmospheric sciences 2024年第6期41卷 1147-1160页

作者： Jiang HUANGFU Zhiqun HU Jiafeng ZHENG Lirong WANG Yongjie ZHU State Key Lab of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Meteorological observatory of Jiangxi Province Nanchang 330096China Hebei Meteorological Disaster Prevention and environmental Meteorological Center Shijiazhuang 050021China school of Atmospheric sciences Chengdu University of Information TechnologyChengdu 610225China

Accurate radar quantitative precipitation estimation(QPE)plays an essential role in disaster prevention and *** this paper,two deep learning-based QPE networks including a single-parameter network and a multi-parameter network are ***,a self-defined loss function(SLF)is proposed during *** dataset includes Shijiazhuang S-band dual polarimetric radar(CINRAD/SAD)data and rain gauge data within the radar’s 100-km detection range during the flood season of 2021 in North *** that the specific propagation phase shift(KDP)has a roughly linear relationship with the precipitation intensity,KDP is set to 0.5°km^(-1 )as a threshold value to divide all the rain data(AR)into a heavy rain(HR)and light rain(LR)***,12 deep learning-based QPE models are trained according to the input radar parameters,the precipitation datasets,and whether an SLF was adopted,*** results suggest that the effects of QPE after distinguishing rainfall intensity are better than those without distinguishing,and the effects of using SLF are better than those that used MSE as a loss function.A Z-R relationship and a ZH-KDP-R synthesis method are compared with deep learning-based *** mean relative errors(MRE)of AR models using SLF are improved by 61.90%,51.21%,and 56.34%compared with the Z-R relational method,and by 38.63%,42.55%,and 47.49%compared with the synthesis ***,the models are further evaluated in three precipitation processes,which manifest that the deep learning-based models have significant advantages over the traditional empirical formula methods.

关键词： polarimetric radar quantitative precipitation estimation deep learning single-parameter network multi-parameter network

Differences in spring precipitation over southern China associated with multiyear La Ni?a events

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Acta Oceanologica Sinica 2024年第2期43卷 1-10页

作者： Guangliang Li Licheng Feng Wei Zhuang Fei Liu Ronghua Zhang Cuijuan Sui National Marine environmental Forecasting Center Ministry of Natural ResourcesBeijing 100081China State Key Laboratory of Marine environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Key Laboratory of Tropical Atmosphere-Ocean System of Ministry of Education/school of Atmospheric sciences Sun Yat-Sen UniversityZhuhai 519082China school of Marine sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Composite analyses were performed in this study to reveal the difference in spring precipitation over southern China during multiyear La Ni?a events during 1901 to 2015. It was found that there is significantly below-normal precipitation during the first boreal spring, but above-normal precipitation during the second year. The difference in spring precipitation over southern China is correlative to the variation in western North Pacific anomalous cyclone(WNPC), which can in turn be attributed to the different sea surface temperature anomaly(SSTA) over the Tropical Pacific. The remote forcing of negative SSTA in the equatorial central and eastern Pacific and the local air-sea interaction in the western North Pacific are the usual causes of WNPC formation and *** in the first spring is stronger than those in the second spring. As a result, the intensity of WNPC in the first year is stronger, which is more likely to reduce the moisture in southern China by changing the moisture transport, leading to prolonged precipitation deficits over southern China. However, the tropical SSTA signals in the second year are too weak to induce the formation and maintenance of WNPC and the below-normal precipitation over southern China. Thus, the variation in tropical SSTA signals between two consecutive springs during multiyear La Ni?a events leads to obvious differences in the spatial pattern of precipitation anomaly in southern China by causing the different WNPC response.

关键词： multiyear La Nina precipitation anomaly anomalous western North Pacific cyclone southern China

Interdecadal Change of the Relationship between Early Summer Precipitation over Northeast China and Spring Land Surface Thermal Anomalies in West Asia

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Journal of Meteorological Research 2024年第4期38卷 720-732页

作者： Hongjun SUN Haishan CHEN Xinguan DU Yinshuo DONG Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)Nanjing University of Information Science&TechnologyNanjing 210044 school of Atmospheric sciences Nanjing University of Information Science&TechnologyNanjing 210044

Recent studies have suggested a close relationship between early summer precipitation over Northeast China and spring land surface thermal anomalies in West ***,is this relationship the same over the multidecadal timescale? This study aims to identify the long-term variation in this relationship and the accompanying atmospheric circulation anomalies by using singular value decomposition,correlation analysis,and linear regression based on the ECMWF Reanalysis v5(ERA5) atmospheric data,ERA-Land reanalysis,and CN05 gridded observations during1961–2020(60 yr).It is found that an interdecadal transition of the relationship between the spring surface temperature/thermal anomalies in West Asia and early summer precipitation over Northeast China occurred around 1990,and the temperature–rainfall relationship intensified after *** on the Mann–Kendall test,the study period was divided into P1(1961–1990) and P2(1991–2020).Further analysis indicated significant differences in the corresponding atmospheric circulation before and after the interdecadal *** P2,spring land surface warming in West Asia corresponded to a significantly enhanced early summer Circumglobal Teleconnection(CGT),which in turn suppressed the Northeast China cold vortex(NECV).The changes in circulation patterns further resulted in weakened moisture transport,strengthened subsidence,reduced precipitation triggering,and eventually,weakened ***,the results suggest that the interdecadal transition of the relationship and the changes in the corresponding atmospheric circulation may be related to activities of the westerly jet *** second principal component(PC2) mode of empirical orthogonal function(EOF) of zonal wind in June over Asia demonstrated a pattern similar to that of the atmospheric circulation corresponding to land surface thermal *** addition,during P2,the PC2 mode of the westerly jet stream in June showed a strong positive correlation

关键词： land–atmosphere interaction interdecadal variation land surface surface temperature

Drug-induced mucosal alterations observed during esophagogastroduodenoscopy

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World Journal of Gastroenterology 2024年第16期30卷 2220-2232页

作者： Masaya Iwamuro Seiji Kawano Motoyuki Otsuka Department of Gastroenterology and Hepatology Okayama University Graduate School of MedicineDentistryand Pharmaceutical SciencesOkayama 700-8558Japan

Several features of drug-induced mucosal alterations have been observed in the upper gastrointestinal tract,i.e.,the esophagus,stomach,and *** include pill-induced esophagitis,desquamative esophagitis,worsening of gastroesophageal reflux,chemotherapy-induced esophagitis,proton pump inhibitor-induced gastric mucosal changes,medication-induced gastric erosions and ulcers,pseudomelanosis of the stomach,olmesartan-related gastric mucosal inflammation,lanthanum deposition in the stomach,zinc acetate hydrate tabletinduced gastric ulcer,immune-related adverse event gastritis,olmesartan-associated sprue-like enteropathy,pseudomelanosis of the duodenum,and lanthanum deposition in the *** endoscopists,acquiring accurate knowledge regarding these diverse drug-induced mucosal alterations is crucial not only for the correct diagnosis of these lesions but also for differential diag-nosis of other *** minireview aims to provide essential information on druginduced mucosal alterations observed on esophagogastroduodenoscopy,along with representative endoscopic images.

关键词： Diagnosis Esophagogastroduodenoscopy Non-neoplastic lesions Esophageal lesions Gastric lesions Duodenal lesions

Properties and Characteristics of Certain Subclass of Close-to-Convex Harmonic Mappings

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Journal of Mathematical Research with Applications 2024年第5期 648-658页

作者： Jiong SHI Zhigang WANG Xiaoyuan WANG school of Mathematics and Statistics Changsha University of Science and Technology school of Mathematics and Statistics Hunan First Normal University school of Mathematics and Statistics Nanjing University of Science and Technology graduate school of information sciences Tohoku University

In this paper, we study a subclass of close-to-convex harmonic mappings whose analytic parts are starlike mappings. We derive some properties and characteristics for this class, such as the bounds of Toeplitz determin...

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