Spatiotemporal analysis of COVID-19 risk in Guangdong Province based on population migration

Population migration,especially population inflow from epidemic areas,is a key source of the risk related to the coronavirus disease 2019(COVID-19)epidemic.This paper selects Guangdong Province,China,for a case study.It utilizes big data on population migration and the geospatial analysis technique to develop a model to achieve spatiotemporal analysis of COVID-19 risk.The model takes into consideration the risk differential between the source cities of population migration as well as the heterogeneity in the socioeconomic characteristics of the destination cities of population migration.It further incorporates a time-lag process based on the time distribution of the onset of the imported cases.In theory,the model will be able to predict the evolutional trend and spatial distribution of the COVID-19 risk for a certain time period in the future and provide support for advanced planning and targeted prevention measures.The research findings indicate the following:(1)The COVID-19 epidemic in Guangdong Province reached a turning point on January 29,2020,after which it showed a gradual decreasing trend.(2)Based on the time-lag analysis of the onset of the imported cases,it is common fora time interval to exist between case importation and illness onset,and the proportion of the cases with an interval of 1-14 days is relatively high.(3)There is evident spatial heterogeneity in the epidemic risk;the risk varies significantly between different areas based on their imported risk,susceptibility risk,and ability to prevent the spread.(4)The degree of connectedness and the scale of population migration between Guangdong’s prefecture-level cities and their counterparts in the source regions of the epidemic,as well as the transportation and location factors of the cities in Guangdong,have a significant impact on the risk classification of the cities in Guangdong.The first-tier cities-Shenzhen and Guangzhou-are high-risk regions.The cities in the Pearl River Delta that are adjacent to Shenzhen and Guangzhou,including Dongguan,Foshan,Huizhou,Zhuhai,Zhongshan,are medium-risk cities.The eastern,northern,and western parts of Guangdong,which are outside of the metropolitan areas of the Pearl River Delta,are considered to have low risks.Therefore,the government should develop prevention and control measures that are specific to different regions based on their risk classification to enable targeted prevention and ensure the smooth operation of society.

Population migration across the Qinghai-Tibet Plateau:Spatiotemporal patterns and driving factors

Developing a comprehensive understanding of inter-city interactions is crucial for regional planning.We therefore examined spatiotemporal patterns of population migration across the Qinghai-Tibet Plateau(QTP)using migration big data from Tencent for the period between 2015 and 2019.We initially used decomposition and breakpoint detection methods to examine time-series migration data and to identify the two seasons with the strongest and weakest population migration levels,between June 18th and August 18th and between October 8th and February 15th,respectively.Population migration within the former period was 2.03 times that seen in the latter.We then used a variety of network analysis methods to examine population flow directions as well as the importance of each individual city in migration.The two capital cities on the QTP,Lhasa and Xining,form centers for population migration and are also transfer hubs through which migrants from other cities off the plateau enter and leave this region.Data show that these two cities contribute more than 35%of total population migration.The majority of migrants tend to move within the province,particularly during the weakest migration season.We also utilized interactive relationship force and radiation models to examine the interaction strength and the radiating energy of each individual city.Results show that Lhasa and Xining exhibit the strongest interactions with other cities and have the largest radiating energies.Indeed,the radiating energy of the QTP cities correlates with their gross domestic product(GDP)(Pearson correlation coefficient:0.754 in the weakest migration season,WMS versus 0.737 in the strongest migration season,SMS),while changes in radiating energy correlate with the tourism-related revenue(Pearson correlation coefficient:0.685).These outcomes suggest that level of economic development and level of tourism are the two most important factors driving the QTP population migration.The results of this analysis provide critical clarification guidance regarding huge QTP development differences.

Association between population migration and epidemic control of coronavirus disease 2019

Dear Editor,In January 2020,a widespread outbreak of coronavirus disease 2019(COVID-19)occurred after the beginning of the largest annual migration in China,which is known as the Spring Festival migration.Starting in January 20,2020,the Chinese government took a series of unprecedented measures to contain the spread of COVID-19.Because of the role of Wuhan as a central transportation hub.

Mechanism of Population Migration and Tendency of Urbanization in Labor Export Regions Based on the Push-and-Pull Model:A Case Study of Huaiyuan County in Northern Anhui Province

Surplus rural workers seek employment through inter-provincial migration, which was once a path to urbanization in labor export regions, and contributed a lot to the economic and social development of both the labor export regions and labor import regions. But in recent years the labor shortage in eastern regions indicates new changes of the Chinese population structure and migration. Based on the macro statistical analysis and f ield survey, this paper analyzes Huaiyuan County in northern Anhui Province by using the push-and-pull model as the analytical framework. Then it explores the mechanism of population migration and the tendency of urbanization from the aspects of the pull from labor import regions and the push from labor export regions. The study shows that both the pull from labor import regions and the push from labor export regions are decreasing, and reverse population migration may occur. Therefore, to accommodate such changes, labor export regions should transfer from "Laborers Migrating for Employment" to "Industry Transfer for Laborers" to promote healthy urbanization. Finally, it proposes further discussions in combination with the National New Urbanization Plan(2014 – 2020).

Correlation of the epidemic spread of COVID-19 and urban population migration in the major cities of Hubei Province, China

This study analyses the relationship between the epidemic spread of COVID-19 and urban population migration in Hubei Province,China.Based on an improved gravity model,the population inflow numbers for each city from 10 January to 23 February are estimated.A correlation analysis is done to reveal the impact of population inflow on the number of infected people in the 14 days after 23 January,the day Wuhan was locked down.The results show that:(i)the population outflow from Wuhan was mostly distributed between Xiaogan,Huanggang,Ezhou and Huangshi in Hubei Province;(ii)the number of accumulated confirmed patients is closely associated with inflows from Wuhan,which displayed by correlation coefficient 1 with a mean of 0.88 and a maximum of 0.93.Meanwhile,there is a weak correlation between the number of people that came from cities except Wuhan and accumulated confirmed patients,which indicated by correlation coefficient 2 with a mean of 0.65 and a maximum of 0.75;and(iii)the total population inflow is a greater predictor of epidemic spread than the population inflow from Wuhan.

Population Migration and Urbanization——Notes on the seminar on the Chinese population migration and urbanization

The academic seminar on China’s pop-ulation migration and urbanization was heldin Beijing from December 14 to 17,1987.More than 100 population and economicworkers and workers in related fields fromdifferent scientific research and educationalinstitutions and executive departments allover the country took part in the seminar.Over 70 papers were presented at the semi-nar.

Regularity of population occurrence and migration in the oriental armyworm, Mythimna separata(Walker)

The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much of the uniquely difficult aspects of managing M.separata arises from its long-distance migratory behavior.For example,direction and timing of winds from its overwintering regions in the south largely determine where and when large influxes of migrants arrive in the north to oviposit,making prediction of infestations difficult.

Specialization and Coordination: New Paradigm, Theory, and Path for Regional Development

In its new development stage,China seeks to derive new dynamism from reform and opening up at a higher level to boost consumption and services.This process coincides with a further differentiation of comparative advantages across regions.Economic activity and population will continue to concentrate in clusters in coastal and central cities amid a continuous outflow of population from remote areas.Development expansion from coastal to interior regions and from central cities to the periphery will promote a new regional development paradigm of“dual centers and periphery”.Therefore,China’s regional development strategy should follow the new theory of seeking relative equilibrium amid development,identify regions of population inflow and outflow,and explore a new development path of regional specialization and coordination.By deepening market reforms and increasing central government coordination,the country is poised to improve the spatial allocation of resources and unleash institutional dividends in the process of developing a unified national market.

Impacts of Rural-urban Migration on Food Consumption

Due to limitation of resource conditions,rural-urban migration leads to increased food consumption and aggravates the tight balance between food supply and demand.This issue has attracted increasing attention.This paper analyzed the food consumption level and structure of migrant workers,changes in food consumption before and after entering the city,the change range of food consumption and the main influencing factors.Data analysis indicated that there are large differences in the quantity and structure of food consumption of migrant workers in different industries and regions.Migrant workers whose food consumption increased after entering the city were more than those whose food consumption decreased.The increase in income and the management of food provided by work units are the main factors influencing the increase in food consumption.

Population synthesis of planet formation using a torque formula with dynamic effects

Population synthesis studies into planet formation have suggested that distributions consistent with observations can only be reproduced if the actual Type Ⅰ migration timescale is at least an order of magnitude longer than that deduced from linear theories.Although past studies considered the effect of the Type I migration of protoplanetary embryos,in most cases they used a conventional formula based on static torques in isothermal disks,and employed a reduction factor to account for uncertainty in the mechanism details.However,in addition to static torques,a migrating planet experiences dynamic torques that are proportional to the migration rate.These dynamic torques can impact on planet migration and predicted planetary populations.In this study,we derived a new torque formula for Type Ⅰ migration by taking into account dynamic corrections.This formula was used to perform population synthesis simulations with and without the effect of dynamic torques.In many cases,inward migration was slowed significantly by the dynamic effects.For the static torque case,gas giant formation was effectively suppressed by Type I migration;however,when dynamic effects were considered,a substantial fraction of cores survived and grew into gas giants.

Translocality:A Re-recognition of Locality in Western Geography

Translocality,as a re-recognition of locality in western Geography,has gradually become an important theoretical framework for understanding the increasingly interconnected global world.By focusing on sorting out the context and main topics of current western geography on translocality research,it reached the following conclusions.(i)From the perspective of geography,translocality research can be roughly divided into initial development stage,stable development stage and high-speed development stage.(ii)Existing studies on migration,urbanization,and social resilience form the knowledge base for translocality research from the perspective of geography.Migration,mobility,and politics are hot topics of translocality research.(iii)Current issues mainly focus on the characteristics of translocal behavior,the impact of translocal behavior,translocal circular flow and gender research in translocal behavior.Based on this,it proposed the important trends that translocality research in China needs to pay attention.

China's long-term low carbon transition pathway under the urbanization process

This study develops a comprehensive analysis framework and socio-economic energy system model that interlinks demographic change and energy system in order to analyze the urbanization process and its relation with China's long-term CO2 emissions trend as China'economy enters the“new normal”stage.The results show that,around 300 million people are expected to migrate from rural areas to urban areas by 2050 following a trend,in which people are moving gradually from small and medium city groups to large and super city groups.The migration trend together with the improvement in living standard will promote China's infrastructure construction,industry production,and energy service demand growth.Under the Business as Usual(BAU)scenario,total primary energy consumption in China will reach 8.4 Gtce by 2050,energyrelated CO2 emissions will increase to 17.6 Gt,which is 83%higher than the 2013 level.While in the Low Carbon Transition(LCT)scenario with technology innovation,the total primary energy demand for China in 2050 could be controlled at^6 Gtce;CO2 emissions would peak during 2020—2025,and be reduced by 78%by 2050 compared to the BAU scenario.In the transition process,non-fossil fuel power generation and energy efficiency technologies have the largest mitigation potentials.Industry and power sectors would peak first before 2020,followed by the building and transport sectors which are projected to peak around 2030.The total additional capital investment required for LCT would account for 1.5%of GDP.Therefore,it is technologically and economically feasible for China to implement new urbanization strategy.

A Simple Discussion on the Supply and Demand of Water Resources in the Western Region of China

We are accustomed to solve the problem of the water scarcity in the western region by the thought of increasing the effective supply of water to meet the needs of Go-west Campaign. After introducing the dynamic equilibrium principle on supply and demand in economy, we find that we should solve the problem of the water scarcity in the western region through reducing total demand to achieve the dynamic equilibrium of supply and demand. Finally water resources in the western region can be enlarged by an accumulated way.

人口流动视角下的耕地利用行为及其影响因素研究

Due to rapid socio-economic development and urban-rural integration,the rural population is increasingly moving away from the primary industry,leading to a noticeable transformation of rural farmland use.This paper analyzed the changes in farmland use and the mechanisms in 213 villages of Longxi county,China in 2020,using multiple linear regression models,based on the aforementioned situation.Analysis revealed main findings:(1)Male and young and middle-aged emigration levels are concentrated in areas with higher and lower values,the emigration of talent is more evenly distributed.Overall,male emigration rates were high in all directions and low in the central area,whereas the young and middle-aged emigration rates exhibited a pattern of high loss in the north and south extremes,and low loss in the central area.The emigration of talent demonstrated a pattern of low losses to the east and high losses to the west of the G30 national highway.(2)Primary farmland use behavior was self-cultivation,then abandonment and finally transfer,with over 60%of the total area in 179 villages used for self-cultivation compared to less than 5%in 164 villages allocated for transfer,while less than 30%of the area in 179 villages was abandoned.(3)Significant differences were observed in the factors that influenced various farmland use behaviors,emigration of male,young and middle-aged and talent were the common influencing factors observed among all three types of farmland uses.The loss of males,young and middle-aged had a significant association with reduced self-cultivation while the emigration of talent led to an increase in self-cultivation use.Increased emigration of all three population constituencies significantly increased farmland transfer and abandonment.The conclusions carry significant theoretical and practical implications for enhancing the coordination of rural human-land relationships and improvement of the understanding of the relationship between population migration and farmland use.

Spatio-temporal evolution of population and urbanization in the countries along the Belt and Road 1950–2050

This paper uses data for the period 1950-2050 compiled by the United Nations Population Division together with methods including spatial autocorrelation analysis, hie- rarchical cluster analysis and the standard deviational ellipse, to analyze the spatio-temporal evolution of population and urbanization in the 75 countries located along the routes of the Silk Road Economic Belt and the 21st-century Maritime Silk Road, to identify future popula- tion growth and urbanization hotspots. The results reveal the following： First, in 2015, the majority of Belt and Road countries in Europe, South Asia and Southeast Asia had high population densities, whereas most countries in Central Asia, North Africa and West Asia, as well as Russia and Mongolia, had low population densities; the majority of countries in South Asia, Southeast Asia, Central Asia, West Asia and North Africa had rapid population growth, whereas many countries in Europe had negative population growth; and five Belt and Road countries are in the initial stage of urbanization, 44 countries are in the acceleration stage of urbanization, and 26 are in the terminal stage of urbanization. Second, in the century from 1950 to 2050, the mean center of the study area＇s population is consistently located in the border region between India and China. Prior to 2000, the trajectory of the mean center was from northwest to southeast, but from 2000 it is on a southward trajectory, as the population of the study area becomes more concentrated. Future population growth hotspots are predicted to be in South Asia, West Asia and Southeast Asia, and hotspot countries for the period 2015-2030 include India, China, Pakistan and Indonesia, though China will move into nega- tive population growth after 2030. Third, the overall urban population of Belt and Road coun- tries increased from 22% in 1950 to 49% in 2015, and it is expected to gradually catch up with the world average, reaching 64% in 2050. The different levels of urbanization in different countries display significant spatial dependency, and in the hundred-year period under con-sideration, this dependency increases before eventually weakening. Fourth, between 2015 and 2030, urban population hotspots will include Thailand, China, Laos and Albania, while Kuwait, Cyprus, Qatar and Estonia will be urban ＂coldspots.＂ Fifth, there were 293 cities with populations over 1 million located along the Belt and Road in 2015, but that number Js ex- pected to increase to 377 by 2030. Of those, 43 will be in China, with many of the others located in India, Indonesia and the eastern Mediterranean.

The trends of migration in China, 1949-2019

Based on relevant policy documents and census data,the authors analyze the characteristics and trends of China’s population migration since the founding of People’s Republic of China(PRC)in 1949.The study finds that over the past 70 years,population migration in China has exhibited distinct stage-specific characteristics.From the founding of PRC to the period of reform and opening-up that got underway in 1978,China witnessed a shift from free population movement to restricted population movement,as well as a shift from population movement driven by the recovery of national economy to that driven by political reasons.With the launch of the reform and opening-up policy,China’s population migration entered an entirely new stage of development,exhibiting the following trends:(1)population migration was highly active,and there were changes in the size of the migrant population;(2)with regard to the direction of migration,rural to urban migration remained the dominant pattern,but the proportion of urban to urban migrants also rose;(3)with regard to the choice of destination,inter-provincial migrants were increasingly concentrated in the coastal areas of Eastern China,whilst the large cities in the Central and Western China were more favored by intra-provincial migrants;(4)the distances inter-provincial migrants traveled increased;(5)migration was motivated mainly by economic factors,yet the importance of social factors was on the rise;and(6)the educational level of migrants went up significantly and the sex ratio gradually became balanced.Accordingly,we must gain a deeper understanding of the trends and characteristics of population migration,taking into consideration the interrelationship between population migration and socioeconomic development.To begin,the equalization of basic public services and thorough-going reform of the household registration system can contribute to the development of a new urbanization strategy.

Air pollutant emissions induced by rural-to-urban migration during China's urbanization(2005-2015)

As the world's most populous country,China has witnessed rapid urbanization in recent decades,with population migration from rural to urban(RU)regions as the major driving force.Due to the large gap between rural and urban consumption and investment level,large-scale RU migration impacts air pollutant emissions and creates extra uncertainties for air quality improvement.Here,we integrated population migration assessment,an environmentally extended inputeoutput model and structural decomposition analysis to evaluate the NOx,SO2 and primary PM2.5 emissions induced by RU migration during China's urbanization from 2005 to 2015.The results show that RU migration increased air pollutant emissions,while the increases in NOx and SO2 emissions peaked in approximately 2010 at 2.4 Mt and 2.2 Mt,accounting for 9.2%and 8.7%of the national emissions,respectively.The primary PM2.5 emissions induced by RU migration also peaked in approximately 2012 at 0.3 Mt,accounting for 2.8%of the national emissions.The indirect emissions embodied in consumption and investment increased,while household direct emissions decreased.The widening gap between urban and rural investment and consumption exerted a major increasing effect on migration-induced emissions;in contrast,the falling emission intensity contributed the most to the decreasing effect benefitting from end-of-pipe control technology applications as well as improving energy efficiency.The peak of air pollutant emissions induced by RU migration indicates that although urbanization currently creates extra environmental pressure in China,it is possible to reconcile urbanization and air quality improvement in the future with updating urbanization and air pollution control policies.

Genetic investigation of haemoglobinopathies in a large cohort of asymptomatic individuals reveals a higher carrier rate for b-thalassaemia in Sichuan Province (Southwestern China)

The incidence of haemoglobinopathy is high in China,especially south of the Yangtze River.However,the exact status of haemoglobinopathy in Sichuan is unknown.To carry out a detailed research of haemoglobinopathy in individuals living in Sichuan,13,298 subjects without clinical symptoms who were living in Sichuan Province,with an age distribution of 5e73 years,were included in this study.Between March 2014 and July 2017,these subjects received examinations at the Medical Lab of Chengdu Women’s&Children’s Central Hospital.Mean corpuscular volume(MCV)<82 fL or mean corpuscular haemoglobin(MCH)<27 pg was used to indicate haemoglobinopathy carriers.Abnormal haemoglobin was screened by electrophoresis,and genes were sequenced to identify genotypes.Genotype diagnosis of alpha-and beta-thalassaemia was carried out by using PCR and shunt hybridization.There were 638 suspected haemoglobinopathy carriers(4.80%,638/13,298).DNA sequencing identified 6 subjects with abnormal haemoglobin genotypes and 15 subjects with Hb E.The frequency of heterozygosity for thalassaemia was 4.12%(1.48%for α-thalassaemia and 2.61%for β-thalassaemia)in Sichuan Province.The mutation spectrum of α-thalassaemia consisted of the five most common mutations:–^(SEA),-α^(3.7),-α^(4.2),α^(CS),and α^(QS).Seven types of β-thalassaemia mutation were found in this study:CD41-42(-TTCT)was the most frequent(28.47%),followed by 17(A>T),28(A>G),and IVS-Ⅱ-654(C>T).The main abnormal haemoglobin genotype(HbE)and thalassaemia genotype(–^(SEA),CD41-42(-TTCT))were consistent with those in other regions of China,but the carrier rate of β-thalassaemia in Sichuan was higher than that of α-thalassaemia.

The settlement intention of urban-to-urban migrants in China:Spatial differences and driving factors

China has entered the middle-to-late stage of urbanization.The scale of urbanto-urban migrants,which more refers to the urban-to-urban floating population(UUFP)across China,has significantly increased.UUFP settlement intention is a crucial issue for urbanization development.This study examines the spatial pattern and factors influencing the settlement intention of the UUFP in China based on data obtained through its dynamic monitoring in 2017 and the binary logistic model.The results show that most members of the UUFP were married,older,better educated,and had a higher income than the average person with extensive migration experience.We correlated a high settlement intention with developed economies,coastal areas,good environmental conditions,and more amenities in cities such as Beijing,Tianjin,Shanghai,and Zhuhai.Amenities were more impactful on settlement intention than economic factors,from individual and regional perspectives.The UUFP more often sought equality of education for children and social integration in its choices of destinations.However,the distance was not a hindrance to intention to settle but played a substantial role in influencing it.We suggest optimizing the stock of the UUFP in large cities,improving public education services,and promoting remote urbanization.Likewise,industrial transfer and enhanced public resources may ease the pressure of large UUFP flows into large cities.

ANALYSIS OF REGIONAL ECONOMY GROWTH WITH THE THEORY OF DIFFERENTIAL SYSTEM DYNAMICS

In order to describe the interrelation forces among different regions during the economic growth, this paper introduces and analyzes the dynamical system model with the theory of differential systems dynamics. A practical example based on a simplified model is given to analyze the dynamical process of Sichuan economy growth.