Migration Networks Pattern of China’s Floating Population from the Perspective of Complex Network

Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the eastern coastal areas to the inland,the migration direction and pattern of the floating population have undergone certain changes.Using the 2017 China Migrants Dynamic Survey(CMDS),excluding Hong Kong,Macao,and Taiwan regions of China,organized by China’s National Health Commission,the relationship matrix of the floating population is constructed according to the inflow place of the interviewees and their outflow place(the location of the registered residence)in the questionnaire survey.We then apply the complex network model to analyze the migration direction and network pattern of China’s floating population from the city scale.The migration network shows an obvious hierarchical agglomeration.The first-,second-,third-and fourth-tier distribution cities are municipalities directly under the central government,provincial capital cities,major cities in the central and western regions and ordinary cities in all provinces,respectively.The migration trend is from the central and western regions to the eastern coastal areas.The migration network has‘small world’characteristics,forming nine communities.It shows that most node cities in the same community are closely linked and geographically close,indicating that the migration network of floating population is still affected by geographical proximity.Narrowing the urban-rural and regional differences will promote the rational distribution this population.It is necessary to strengthen the reform of the registered residence system,so that the floating population can enjoy urban public services comparable to other populations,and allow migrants to live and work in peace.

Spatial Morphology Evolution Characteristics Analysis of the Resident Population Distribution in Henan, China

The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of a better life society, and promotion of regional economic development. Based on the resident population statistics data of Henan province from 2006 to 2021, with county as the basic study unit, the paper studies the spatial morphology characteristics and its evolution patterns of resident population distribution, by using spatial analysis methods such as population distribution center, standard deviation ellipse, and spatial auto correlation analysis. The results show that: the resident population spatial distribution shows unbalanced state, the population agglomeration areas mainly distribute in the northeast part and north part, where the resident population growth rate is significantly higher than other regions, over time, this trend is gradually becoming significant. The resident population distribution has a trend of centripetal concentration, with the degree and trend of centripetal gradually strengthening. The resident population distribution has obvious directional characteristics, but the significance is not high, the weighted resident population average center is approximately located at (4.13740˚N, 113.8935˚E), and the azimuth of the distribution axis is approximately 11.19˚. The population distribution has obvious agglomeration characteristics, with the built-up areas of Zhengzhou and Luoyang as their centers, where have a significant siphon effect on the surrounding population. The southern and southwestern regions in the province form a relatively stable belt area of Low-Low agglomeration areas.

Early life migration and population discrimination of the small yellow croaker Larimichthys polyactis from the Yellow Sea: inferences from otolith Sr/Ca ratios

The small yellow croaker Larimichthys polyactis is a benthic marine fish species of high ecological and commercial importance and is widely distributed in the northwestern Pacifi c Ocean,especially in the Chinese coastal waters of the Bohai,Yellow,and East China Seas.As a highly migratory species,the whole life migration of L.polyactis has been intensively studied.However,knowledge about its early life migration is scarce,and population divisions are inconsistent,limiting the ability of fishery scientists and administrators to evaluate the design and potential benefits of thorough conservation and resource-management strategies.In the present study,otolith Sr/Ca was analyzed to investigate the early migratory patterns and discriminate the populations of L.polyactis in the Yellow Sea,including two spawning groups and one overwintering group.The variation in Sr/Ca ratios of ontogenetic growth zones,including the nucleus(N),larval(L),metamorphosis(M),juvenile(J),and edge(E)zones,was measured by electron probe microanalysis.The variation in Sr/Ca ratios in early developmental growth zones was generally characterized by an evident downward trend from the N to J zone,which suggests that the early migratory pattern of L.polyactis might be from inshore to nearshore water.Canonical discriminant analysis,based on the otolith Sr/Ca ratios of the N,L,M,and J zones,allowed the successful discrimination of the two populations,namely,the northern and southern Yellow Sea groups,whose diff erences were mainly reflected in the L and J zones.Compared with previous studies,the traditional geographic boundaries(34°N)separating these two populations might be moving northward.The application of otolith Sr/Ca ratios based on ontogenetic stage could improve our understanding of the migration and population discrimination of L.polyactis from the Yellow Sea.

Migration Laws of Floating Population in Mianyang

Based on the overall analysis of the floating population among big and medium-sized cities in China,this paper, by means of statistics and questionnaires, makes a systematical study on the migratory features of the floating population in Mianyang, its employment structure, migrating causes and channels. According to the findings, the author finds a fact that with the strategy of Western Development, and with the construction of science and technology city of Mianyang, the migrating in Mianyang conforms to the general patterns of the migration, which has happened in those big and medium-sized cities in China.In addition,the city has a new but unique feature — economic factor, as the driving force of population migration, is quite distinct from that of those citiesin eastern areas of China.

ON THE RELATIONSHIP BETWEEN MARRIAGE AND POPULATION MIGRATION IN CHINA

As a constant and active factor affecting population migration, marriage has long been neglected. This paper brings to light of the social significance of marriage migration and makes an inquiry into its characteristics, patterns and mechanism. It is thought the marriage plays an important role in hastening population migration. While compared with other forms of population migration, marriage migration is distinctive, showing its own characteristics, such as irreversibility in direction, shorter distance, age long continuity, regional dispersal, gentler fluctuation in number, sexual imbalance, and multiple factors at work. Although the manifestation of marriage migration is complicated, its patterns are clear, that is: pattern 1, women to men’s habitation; pattern 2, men to women’s habitation; and pattern 3, men and women to a third place. It is thought that both the characters and the patterns of marriage migration are determined by its mechanism, because marriage migration is not only a kind of biological action but also a kind of social action, the former of which determines whether it happens, while the latter of which determines how it does. The difference of men’s and women’s social status, that of cities and country, and that of developed and backward areas may result in abnormality of marriage migration, while the socio biological feedback of sexual imbalance and regional environmental deterioration can give rise to some self adjusting mechanism. In the end of the paper, based on a sample analysis, it concludes four tendencies towards marriage migration in China: (1) pair migration is emerging; (2) the changing trend of urban and rural regional relationship of marriage is contrary; (3) urban “island effect” in marriage is weakening; and (4) the potential energy between developed and less developed areas is still strong.

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.

The Empirical Analysis on the Dynamic Effect of Rural-urban Migration on the Consumption Growth of Residents in China——Based on Varying Parameter State-space Model

The research constructed varying parameter state-space model and per- formed estimation on dynamic relationship between urban-rural migration and aggre- gate consumption expenditure on basis of dual economic structure. The results showed that urban consumption growth made the most contribution to aggregate consumption growth, followed by urban-rural migration caused consumption. The role of rural consumption growth kept stable, but consumption caused by population growth was decreasing. Therefore, China consumption growth mainly relies on urban consumption expenditure and urban-rural migration.

Rural-urban Migration, Rural Household Income and Local Geographical Contexts——A Case of Northwestern Guangxi, China

This paper aims to examine New Economics of Labor Migration (NELM) in the northwestern Guangxi, China and investigate the relationships among rural-urban migration, rural household income and local geographical contexts. Stratified sampling and typical case study were adopted and 236 questionnaires were collected from four vil- lages, Daxin, Lixin, Longhe and Yongchang. We analyzed the rural-urban migration rate, household income and local geographical factors, focusing on the ratio of remittance income to total household income. Data descriptions and sta- tistical methods, such as Pearson Chi-square test, Contingency coefficient, Eta, Pearson correlation coefficient, t-test, multiple comparisons (LSD test, Tamhane T2, Dunnett T3 and Dunnet C test) were used. The results are as follows. Rural households’ income is diversified in survey villages so the motivation of rural-urban migration in the study area can be partly explained by NELM. The migration rate of households (the percentage of households with migrants in survey households) in survey villages varies from 50% to 86%, while the proportion of remittance income to house- hold income is in the range of 30% to 80%. In the village of Yongchang, with the least average arable land area per household, the remittance income plays a vital role in household income (80%). And the statistical findings show that the proportion is significantly and negatively correlated with arable land area per household. The conclusion is that di- rect effect of migration, i.e., the contribution of remittance to household income, is negatively correlated with the con- tribution of resources to local income.

Economic Growth, Demographic Change and Rural-Urban Migration in China

Is China able to maintain fast growth after three decades？ This paper tries to answer this question by： 1） arguing that factors contributed to sustained long-run growth at supply side;2） focusing on contributions of demographic dividend especially that of rural-urban migration;and 3） analyzing rural demographic change with information collected through village-wide household survey.Policy alternatives to realize remaining potential demographic dividend are proposed based on the analysis of changing rural demographic structure.

Rural-urban Migration,Rural Household Income and Sustainable Development in Rural Areas of China

The objective of this paper is to investigate the rela- tionships among rural-urban migration,rural household income and sustainable development in rural areas of China.The typical case study is done and 288 questionnaires are collected from five villages in Hebei and Guangxi provinces,China.The migration and remittance status,household income and sustainable devel- opment of rural areas are analyzed on the basis of questionnaires. Rural-urban migration is becoming a part of routine life in rural areas.And remittance is an important component in rural house- hold income.Rural-urban migration increases the arable land area per labor,which releases the tight human-land relationship in villages.In total,the migration increases the rural household in- come and accelerates the sustainable development of rural areas.

Monitoring population dynamics of the migratory Red-crowned Crane (Grus japonensis) at Shuangtaihekou National Nature Reserve,northeastern China,from 1991 to 2012

We studied migratory Red-crowned cranes from 1991-2012 in order to track population dynamics and trends for these cranes over time at Shuangtaihekou,northeastern China.Our results show that the earliest arrival date of the Red-crowned Crane (Grus japonensis) was usually around 1 March in the spring and the latest departure date of the cranes around 8 November.The peak period for the number of cranes observed in the spring was 10-20 March over these 22 years.The staging period in the spring is about 25 days.Comparing the highest number of Red-crowned cranes observed in the spring,the migratory population was around 400 birds in the 1990s,then,increased to over 800 birds in 2000.For a short while,the population maintained itself around 600-800 birds.After that,the population started to decline,until during the most recent years,we observed around 400 birds at peak times of each season.Our results match a similar population change pattern observed in the wintering area for a western population,which has been declining since 2000.There is an urgent need to reinforce protection and management,as well as to maintain and improve the quality of their habitats.

Reconstruct recent multi-population migration history by using identical-by-descent sharing

Identical-by-descent(IBD)is a fundamental genomic characteristic in population genetics and has been widely used for population history reconstruction.However,limited by the nature of IBD,which could only capture the relationship between two individuals/haplotypes,existing IBD-based history inference is constrained to two populations.In this study,we propose a framework by leveraging IBD sharing in multipopulation and develop a method,MatrixiBD,to reconstruct recent multi-population migration history.Specifically,we employ the structured coalescent theory to precisely model the genealogical process and then estimate the IBD sharing across multiple populations.Within our model,we establish a theoretical connection between migration history and IBD sharing.Our method is rigorously evaluated through simulations,revealing its remarkable accuracy and robustness.Furthermore,we apply MatrixiBD to Central and South Asia in the Human Genome Diversity Project and successfully reconstruct the recent migration history of three closely related populations in South Asia.By taking into account the IBD sharing across multiple populations simultaneously,MatrixlBD enables us to attain clearer and more comprehensive insights into the history of regions characterized by complex migration dynamics,providing a holistic perspective on intricate patterns embedded within the recent population migration history.

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.

What Influences The Family Migration Decision of China’s New Generation Rural-urban Migrants? A Multilevel Logistic Regression Analysis

The massive scale of new-generation rural-urban migrants in China has attracted extensive scholarly attention in recent years.While previous studies on China’s rural migrant workers focus on migrants’settlement intentions,migrants’family migration decision-making and the intergenerational differences between the old-generation migrants and new-generation migrants are underexplored.Based on the data of the 2017 China Migrants Dynamic Survey,this paper adopts a multilevel logistic regression approach to explore family and destination factors influencing the family migration decisions of China’s new generation of rural migrant workers.The empirical results reveal that both the migrants’family and destination attributes significantly influence their family migration decision.The demographic and socioeconomic characteristics of the family have been pivotal factors underlying the family migration decision of China’s new generation rural-urban migrants,while 16.9%of the chances are explained by between-destination differences.Self-employed migrants with housing properties in host cities,long migration duration and high-income levels are more likely to migrate with their family members.Yet,the possibility of family migration is found to be significantly and negatively correlated with the age,education level,number of children and inter-provincial mobility of the new generation of migrant workers.In addition,new-generation rural-urban migrants’family migration is more likely to be found in cities with service-oriented industry structures,better environmental quality,and higher hukou barriers which is possibly related to more job opportunities.These research findings not only complement the existing literature on China’s new generation of rural urban migrants,but also have important policy implications for reforming the hukou system and enhancing social integration of the rural-to-urban migrant population.

Effects of population aging on the mortality burden of related cancers in urban and rural areas of China, 2004–2017: a population-based study

Objective:China is a developing country with urban–rural disparities and accelerating population aging.Therefore,quantifying the effects of population aging on the cancer mortality burden is urgently needed.Methods:Using data from China’s death surveillance datasets(2004–2017),we decomposed and quantified the effects of population aging and factor variations on cancer mortality rates in urban and rural China during 2004–2017 through a decomposition method.R ratios were used to assess the extent of the mortality decreases attributable to factor variations offsetting the increases attributable to population aging for 4 aging-related cancers(lung,colorectal,esophageal,and stomach cancer).Results:Overall,population aging has led to continued increases in cancer mortality rates in China during 2004–2017(mortality rates attributable to population aging:8.63/100,000 for urban men,4.21/100,000 for urban women,11.95/100,000 for rural men,and 5.66/100,000 for rural women).The 4 cancers displayed 3 patterns.The mortality rates from lung cancer in rural China and from colorectal cancer nationwide increased because of both population aging and factor variations.Population aging was primarily responsible for the growing mortality due to lung cancer in urban areas.However,for esophageal and stomach cancer,the effect of population aging was not dominant,thus resulting in decreases in mortality rates.Conclusions:Health resource allocation should prioritize areas or cancers more adversely affected by population aging.The burden of cancer will continue to increase in the future,because of rapid population aging,but can still be offset or even reversed with enhanced cancer control and prevention.

Analysis on the migration of first-generation Mythimna separata(Walker) in China in 2013

Mythimna separata（Walker） is an important pest which can cause serious damages to cereal crops. In the past two decades, several heavy outbreaks have taken place in northern China. In order to develop a fine-scale method of forecasting outbreaks, population data were collected in northern China using searchlight traps and ground light traps. A background weather pattern analysis and trajectory analysis were performed via the Weather Research and Forecast（WRF） and FLEXPART models. Our results showed that heavy migration of first-generation M. separata appeared in northern China in 2013. In Yanqing District, Beijing, the cumulative number of captured adults in searchlight traps was around 250000 and the daily maximum for trapped moths was 86000. During the peak period, the majority of M. separata moths arrived after 00：00 every night. The sex ratio（female：male） at each monitoring site was greater than 1 and greatly fluctuated with population dynamics. During the migration peak, prevailing downdraft winds benefited M. separata moths to land passively. Trajectory simulation showed that immigrants were from Anhui, Jiangsu and Hubei provinces and most of them could continue to fly into the northeastern regions of China. These results provide technical support for fine-scale forecasting of the outbreak of M. separata at meso-and micro-scale.

Impacts of Migration on Urban Environmental Pollutant Emissions in China: A Comparative Perspective

In recent years,researchers have devoted considerable attention to identifying the causes of urban environmental pollution.To determine whether migrant populations significantly affect urban environments,we examined the relationship between urban environmental pollutant emissions and migrant populations at the prefectural level using data obtained for 90 Chinese cities evidencing net in-migration.By dividing the permanent populations of these cities into natives and migrants in relation to the population structure,we constructed an improved Stochastic Impacts by Regression on Population,Affluence and Technology model(STIRPAT)that included not only environmental pollutant emission variables but also variables on the cities’attributes.We subsequently conducted detailed analyses of the results of the models to assess the impacts of natives and migrants on environmental pollutant emissions.The main findings of our study were as follows:1)Migrant populations have significant impacts on environmental emissions both in terms of their size and concentration.Specifically,migrant populations have negative impacts on Air Quality Index(AQI)as well as PM2.5 emissions and positive impacts on emissions of NO2 and CO2.2)The impacts of migrant populations on urban environmental pollutant emissions were 8 to 30 times weaker than that of local populations.3)Urban environmental pollutant emissions in different cities differ significantly according to variations in the industrial structures,public transportation facilities,and population densities.

Pairwise Shared Genealogical Ancestry in Structured Populations

Simulation was used to investigate the effects of population structure and migration on metrics of pairwise shared ancestry. Random and hierarchical structures, or migration geometries, were examined. Compared to panmictic populations, progress to all qualitative metrics of pairwise ancestry is delayed in structured populations. However, unless migration is very low, the time required is generally less than triple and often less than twice that required in a panmictic population of the same total size. Population structure also increases, to a similar degree, the time required for a population-wide most recent common ancestor (MRCA). As a result, the relationships between various qualitative metrics of pairwise shared ancestry and MRCA time are relatively unaffected by population structure. For example, the mean time to most recent shared ancestor (MRSA) with global sampling of pairs is 40% - 50% of the MRCA time for almost all simulated structures and migration levels. Quantitative pairwise genealogical overlap is strongly affected by population structure. With global sampling, pairwise quantitative overlap never approaches 1.0, as it does in panmictic populations;and instead eventually becomes stationary at much lower values. Possible implications of the present results for human pairwise shared ancestry are discussed. For globally sampled pairs, the longest time to most recent shared ancestor (MRSA) for humans is suggested to be approximately 2100 years before the present. If generation time is 30 years, then all humans are 69th, or closer, cousins. For people with recent European ancestry, the MRSA time may be only half as long, about 1000 years.

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.

Microgeographic Variation and Inter-Riffle Migration of <i>Rhinichthys atratulus</i>(Pisces: Cyprinidae) in a Small Connecticut Stream, United States

We examined the genetic diversity on a microgeographic scale of Rhinichthys atratulus (Eastern Blacknose Dace) in Allyn Brook, a small tributary in the upper Coginchaug River drainage in Connecticut. By looking at gene flow on a microgeographic scale among populations that had no physical barriers to migration, we tested the null hypothesis that the populations should be homogeneous. We resolved seven polymorphic microsatellite loci and one mitochondrial gene, nd2, in three adjacent populations (<0.5 km) in Allyn Brook and compared these populations to the two closest populations (>5 km) in the Coginchaug River. A dam from the 1920’s in lower Allyn Brook has isolated Allyn-Brook populations from Coginchaug-River populations. Allyn Brook was selected because there are only three riffle habitats in the brook and, therefore, there can be no immigration from upstream populations. Each population has private (i.e., unique) alleles and haplotypes, and there are significant genetic differences between all sites. The Allyn Brook populations are almost as different from one another as they are from the distant populations in the Coginchaug River from which they have been isolated for more than 80 years. These results point to in situ evolution and little migration or gene flow among populations on a microgeographic scale. This raises interesting questions for conservation of genetic diversity of stream fishes.