This paper proposes a new time-varying parameter distributed lag(DL)model.In contrast to the existing methods,which assume parameters to be random walks or regime shifts,our method allows time-varying coefficients of ...This paper proposes a new time-varying parameter distributed lag(DL)model.In contrast to the existing methods,which assume parameters to be random walks or regime shifts,our method allows time-varying coefficients of lagged explanatory variables to be conditional on past information.Furthermore,a test for constant-parameter DL model is introduced.The model is then applied to examine time-varying causal effect of inventory on crude oil price and forecast weekly crude oil price.Time-varying causal effect of US commercial crude oil inventory on crude oil price return is presented.In particular,the causal effect of inventory is occasionally positive,which is contrary to some previous research.It’s also shown that the proposed model yields the best in and out-of-sample performances compared to seven alternative models including RW,ARMA,VAR,DL,autoregressive-distributed lag(ADL),time-varying parameter ADL(TVP-ADL)and DCB(dynamic conditional beta)models.展开更多
目的探讨昼夜温差(diurnal temperature range,DTR)影响慢性肾脏病(chronic kidney diseases,CKD)日住院人次的影响。方法收集2019年1月1日至2020年12月31日乌鲁木齐市4所三甲医院、4所二甲医院、1所一甲医院CKD日住院人次数据,同期气...目的探讨昼夜温差(diurnal temperature range,DTR)影响慢性肾脏病(chronic kidney diseases,CKD)日住院人次的影响。方法收集2019年1月1日至2020年12月31日乌鲁木齐市4所三甲医院、4所二甲医院、1所一甲医院CKD日住院人次数据,同期气象及污染物数据来自于乌鲁木齐市主城区的6个国控监测点,采用分布滞后非线性模型,控制星期几效应、假期效应、长期时间趋势及其它因素,分析DTR与CKD日住院人次的关系。结果CKD日住院人次与DTR(滞后0~21 d)的暴露-反应曲线呈“N”形,CKD患者住院风险随DTR的升高呈先上升后下降趋势。低度和高度DTR对CKD患者住院的影响存在一定的滞后效应,中度DTR对住院影响较小;DTR=5℃时,单日效应出现在第3天[RR=1.081,95%CI(1.020,1.145),P<0.05],最大效应出现在第21天[RR=1.090,95%CI(1.014,1.173),P<0.05];高度DTR=14℃(P_(95))时,单日效应出现在第4天[RR=1.086,95%CI(1.007,1.172),P<0.05],最大效应出现在第5天[RR=1.089,95%CI(1.009,1.176),P<0.05],累积滞后均暂未发现有统计学差异。男性和年龄<65岁的CKD患者更易受到DTR的影响,寒冷季节和四季更替时DTR变化对CKD患者住院的影响更大。结论男性与<65岁CKD患者更易受到DTR的影响,在寒冷季节和四季交替DTR变化时更应重点保护易感人群免受DTR的影响。展开更多
Objective:To assess the correlation between atmospheric pollutants,meteorological factors,and emergency department visits for respiratory diseases in Haikou City.Methods:Daily data on atmospheric pollutants,meteorolog...Objective:To assess the correlation between atmospheric pollutants,meteorological factors,and emergency department visits for respiratory diseases in Haikou City.Methods:Daily data on atmospheric pollutants,meteorological factors,and emergency department visits for respiratory diseases in Haikou City from 2018 to 2021 were collected.The Spearman rank correlation test was used to analyze the correlation,and a distributed lag non-linear model was employed to analyze the health effects and lag impacts of environmental factors.Subgroup analyses were conducted based on sex and age.Results:According to the criteria of International Classification of Diseases(ICD-10:J00-J99),a total of 221913 cases were included,accounting for 21.3%of the total emergency department visits in Haikou City.For every 1℃increase in temperature,the risk of emergency department visits increased by 1.029%(95%CI 1.016%-1.042%).Relative humidity greater than 80%reduced the risk of visits,while higher atmospheric pressure(>1010 hpa)also decreased the likelihood of daily emergency department visits.Higher concentrations of PM2.5(30-50μg/m^(3)),PM10(>60μg/m^(3)),and O_(3)(75-125μg/m^(3))were associated with increased visits.Higher temperatures(>25℃)have a greater impact on females and children aged 0-14 years,while males are more sensitive to low atmospheric pressure.Individuals aged 65 and above exhibited increased sensitivity to O_(3)concentration,and the effects of PM2.5,PM10,and O_(3)are more pronounced in individuals over 14 years old.Conclusions:Short-term exposure to high temperatures,particulate matter pollutants(PM_(2.5)and PM_(10)),and ozone(O_(3))is associated with increased emergency department visits for respiratory diseases.展开更多
目的本研究探索亚热带地区的热浪定义,系统评估热浪对福建省心血管疾病(cardiovascular disease,CVD)及其亚型死亡率的影响。方法收集2007-2015年福建省9个市66854例心血管疾病死亡数,联合分布滞后非线性模型(distributed lag non-linea...目的本研究探索亚热带地区的热浪定义,系统评估热浪对福建省心血管疾病(cardiovascular disease,CVD)及其亚型死亡率的影响。方法收集2007-2015年福建省9个市66854例心血管疾病死亡数,联合分布滞后非线性模型(distributed lag non-linear model,DLNM)和类泊松回归模型评估热浪对各个市每日心血管疾病死亡的影响,然后用多元Meta分析计算综合效应。按CVD亚型、性别、年龄、婚姻和教育水平进行分层分析。结果热浪定义为连续≥4天日平均温度≥P 95拟合心血管疾病死亡的模型最佳。热浪效应是急剧的,热浪发生当天对CVD死亡的相对危险度为1.06(95%CI:1.01~1.12)、滞后1天为1.04(95%CI:1.00~1.07)、累计滞后0-1天相对危险度为1.10(95%CI:1.05~1.16)。热浪增加缺血性心脏病、慢性缺血性心脏病、脑血管疾病的死亡率,累计滞后0-1天的相对危险度分别为1.13(95%CI:1.04~1.23)、1.24(95%CI:1.08~1.43)和1.09(95%CI:1.02~1.16)。此外,≥65岁人群更容易受到热浪效应的影响。结论本研究认为在福建省热浪最佳定义为连续≥4天且日平均温度≥P 95,在该定义下热浪会增加CVD、缺血性心脏病、慢性缺血性心脏病、脑血管疾病的死亡率。此外,≥65岁人群是热浪对心血管疾病死亡效应的脆弱人群。展开更多
Combining vacuum preloading technology and electroosmosis can improve the treatment effect of soft soil foundation by utilizing the advantages of both methods.Many studies indicate that the soil electrical potential i...Combining vacuum preloading technology and electroosmosis can improve the treatment effect of soft soil foundation by utilizing the advantages of both methods.Many studies indicate that the soil electrical potential is non-linearly distributed in the treatment process by the combined method.However,in the previous theoretical study,the non-linear-distribution impacts of soil’s electrical potential on soft soil foundation treatment have not been considered.It is always assumed to be linear distribution,which is different from the experimental results.In this paper,the coupling consolidation model of this technology under the two-dimensional plane strain condition is initially established;and the well resistance effect,the vacuum load decreasing along the soil depth and the non-linear variation of electrical potential in the soil are considered.Then,the analytical solutions of the average excess pore water pressure and soil’s consolidation degree in the anode affected area are acquired based on the soil’s electrical potential distribution.Finally,the rationality of the analytical solution is testified by conducting an experimental model test,which proves the scientificity of the analytical solution.The analytical solution is adopted to better predict the dissipation of excess pore water pressure and soil consolidation degree when using the combined technology.This study can provide a reference with more accuracy for the engineering practices of this combined technology in the future.展开更多
Objective This study aimed to determine the spatiotemporal distribution and epidemiological characteristics of hospital admissions for carbon monoxide poisoning(COP)in Guangdong,China,from 2013 to 2020.Methods Data on...Objective This study aimed to determine the spatiotemporal distribution and epidemiological characteristics of hospital admissions for carbon monoxide poisoning(COP)in Guangdong,China,from 2013 to 2020.Methods Data on age-and sex-specific numbers of hospital admissions due to COP in Guangdong(2013-2020)were collected.Daily temperatures were downloaded through the China Meteorological Data Sharing Service System.We analyzed temporal trends through time series decomposition and used spatial autocorrelation analysis to detect spatial clustering.The distributed lag nonlinear model was used to quantify the effects of temperature.Results There were 48,854 COP admissions over the study period.The sex ratio(male to female)was1:1.74.The concentration ratios(M)ranged from 0.73-0.82.The highest risk occurred in January(season index=3.59).Most cases were concentrated in the northern mountainous areas of Guangdong with high-high clustering.COP in the study region showed significant spatial autocorrelation,and the global Moran’s I value of average annual hospital admission rates for COP was 0.447(P<0.05).Low temperatures were associated with high hospital admission rates for COP,with a lag lasting 7 days.With a lag of 0 days,the effects of low temperatures[5th(12℃)]on COP were 2.24-3.81,as compared with the reference temperature[median(24℃)].Conclusion COP in Guangdong province showed significant temporal and spatial heterogeneity.Low temperature was associated with a high risk of COP,and the influence had a lag lasting 7 days.展开更多
基金National Natural Science Foundation of China(71871213)。
文摘This paper proposes a new time-varying parameter distributed lag(DL)model.In contrast to the existing methods,which assume parameters to be random walks or regime shifts,our method allows time-varying coefficients of lagged explanatory variables to be conditional on past information.Furthermore,a test for constant-parameter DL model is introduced.The model is then applied to examine time-varying causal effect of inventory on crude oil price and forecast weekly crude oil price.Time-varying causal effect of US commercial crude oil inventory on crude oil price return is presented.In particular,the causal effect of inventory is occasionally positive,which is contrary to some previous research.It’s also shown that the proposed model yields the best in and out-of-sample performances compared to seven alternative models including RW,ARMA,VAR,DL,autoregressive-distributed lag(ADL),time-varying parameter ADL(TVP-ADL)and DCB(dynamic conditional beta)models.
基金the National Natural Science Foundation of China(No:81960351)Research Foundation for Advanced Talents of Hainan(No:822RC835)Province Natural Science Key Foundation of Hainan(No:ZDYF 2019125).
文摘Objective:To assess the correlation between atmospheric pollutants,meteorological factors,and emergency department visits for respiratory diseases in Haikou City.Methods:Daily data on atmospheric pollutants,meteorological factors,and emergency department visits for respiratory diseases in Haikou City from 2018 to 2021 were collected.The Spearman rank correlation test was used to analyze the correlation,and a distributed lag non-linear model was employed to analyze the health effects and lag impacts of environmental factors.Subgroup analyses were conducted based on sex and age.Results:According to the criteria of International Classification of Diseases(ICD-10:J00-J99),a total of 221913 cases were included,accounting for 21.3%of the total emergency department visits in Haikou City.For every 1℃increase in temperature,the risk of emergency department visits increased by 1.029%(95%CI 1.016%-1.042%).Relative humidity greater than 80%reduced the risk of visits,while higher atmospheric pressure(>1010 hpa)also decreased the likelihood of daily emergency department visits.Higher concentrations of PM2.5(30-50μg/m^(3)),PM10(>60μg/m^(3)),and O_(3)(75-125μg/m^(3))were associated with increased visits.Higher temperatures(>25℃)have a greater impact on females and children aged 0-14 years,while males are more sensitive to low atmospheric pressure.Individuals aged 65 and above exhibited increased sensitivity to O_(3)concentration,and the effects of PM2.5,PM10,and O_(3)are more pronounced in individuals over 14 years old.Conclusions:Short-term exposure to high temperatures,particulate matter pollutants(PM_(2.5)and PM_(10)),and ozone(O_(3))is associated with increased emergency department visits for respiratory diseases.
基金Project(51979087)supported by the National Natural Science Foundation of ChinaProject(BK20180776)supported by the Jiangsu Natural Science Foundation,ChinaProject(202006710002)supported by the China Scholarship Council。
文摘Combining vacuum preloading technology and electroosmosis can improve the treatment effect of soft soil foundation by utilizing the advantages of both methods.Many studies indicate that the soil electrical potential is non-linearly distributed in the treatment process by the combined method.However,in the previous theoretical study,the non-linear-distribution impacts of soil’s electrical potential on soft soil foundation treatment have not been considered.It is always assumed to be linear distribution,which is different from the experimental results.In this paper,the coupling consolidation model of this technology under the two-dimensional plane strain condition is initially established;and the well resistance effect,the vacuum load decreasing along the soil depth and the non-linear variation of electrical potential in the soil are considered.Then,the analytical solutions of the average excess pore water pressure and soil’s consolidation degree in the anode affected area are acquired based on the soil’s electrical potential distribution.Finally,the rationality of the analytical solution is testified by conducting an experimental model test,which proves the scientificity of the analytical solution.The analytical solution is adopted to better predict the dissipation of excess pore water pressure and soil consolidation degree when using the combined technology.This study can provide a reference with more accuracy for the engineering practices of this combined technology in the future.
基金supported by National Institute for Occupational Health and Poison Control,Chinese Center for Disease Control and Prevention Chemical Poisoning Treatment base and Health Emergency Team Operation[131031109000160007]
文摘Objective This study aimed to determine the spatiotemporal distribution and epidemiological characteristics of hospital admissions for carbon monoxide poisoning(COP)in Guangdong,China,from 2013 to 2020.Methods Data on age-and sex-specific numbers of hospital admissions due to COP in Guangdong(2013-2020)were collected.Daily temperatures were downloaded through the China Meteorological Data Sharing Service System.We analyzed temporal trends through time series decomposition and used spatial autocorrelation analysis to detect spatial clustering.The distributed lag nonlinear model was used to quantify the effects of temperature.Results There were 48,854 COP admissions over the study period.The sex ratio(male to female)was1:1.74.The concentration ratios(M)ranged from 0.73-0.82.The highest risk occurred in January(season index=3.59).Most cases were concentrated in the northern mountainous areas of Guangdong with high-high clustering.COP in the study region showed significant spatial autocorrelation,and the global Moran’s I value of average annual hospital admission rates for COP was 0.447(P<0.05).Low temperatures were associated with high hospital admission rates for COP,with a lag lasting 7 days.With a lag of 0 days,the effects of low temperatures[5th(12℃)]on COP were 2.24-3.81,as compared with the reference temperature[median(24℃)].Conclusion COP in Guangdong province showed significant temporal and spatial heterogeneity.Low temperature was associated with a high risk of COP,and the influence had a lag lasting 7 days.
