• Journal of Ecology and Environment
• /
• v.46 no.1
• /
• pp.1-7
• /
• 2022

Background: In this study, we proposed that the population dynamics of non-native red-eared sliders (Trachemys scripta elegans) depends on the species' habitat extension and survivorship. We used a logistic equation with time-dependent habitat carrying capacity. In detail, the present carrying capacity depends on the red-eared slider population of the previous year. Anthropogenic activities such as the abandonment of previously captive red-eared sliders or the release due to religion customs would supply new habitats to the species. Therefore we assumed that anthropogenic spread increases the habitat carrying capacity. Based on the urbanization increase rate of 3% in Korea from 1980 to 2000, we assumed an annual spread of 3% to simulate the population dynamics of the red-eared slider. In addition, the effect on the population of an increase of natural habitats due to migration was simulated. Results: The close relationship between the distributions of non-native red-eared sliders and of urbanized areas demonstrates that urbanization plays an important role in providing new habitats for released individuals. Depending on the survivorship, the population of the red-eared slider in Korea increased 1.826 to 3.577 times between 1980 and 2000. To control population growth, it is necessary to reduce carrying capacity by reducing habitat expansion through prohibition of release into the wild ecosystem and careful managements of the wetland or artificial ponds. Changes in the habitat carrying capacity showed that the population fluctuated every other year. However, after several years, it converged to a consistent value which depended on the survivorship. Further, our results showed that if red-eared sliders expand their habitat by natural migration, their population can increase to a greater number than when they have a 99% survivorship in a fixed habitat. Conclusions: Further introductions of red-eared sliders into wetlands or artificial ponds should be prohibited and managed to prevent future spread of the species. Moreover, it is important to reduce the species' survivorship by restoring disturbed ecosystems and maintaining healthy ecosystems.

• Journal of Preventive Medicine and Public Health
• /
• v.7 no.1
• /
• pp.197-201
• /
• 1974

The rapid economic development of Korea since 1960 has also brought a rapid urbanization process, and recently many rural areas have begun to show actual depopulation, in which particularly the young, productive and high educated groups are leaving for cities. More than 70% of migrators go to large cities such as Seoul, Pusan and Taegu. Their main motives for migration are to seek a job in urban areas. The study showed following results; The rate of migration a year was 1% of total population. Regarding the age of migrators belong to between 10-39 years old, especially migrator aged 10-29 years are comprised 87%. The educational level of migrators was a little higher than that of the residents. Considering the sibling order of migrators, the traditional value system for first son seemed to change. Concerning the place of destination, more than 70% of migrators moved to large cities such as Seoul. Pusan and Taegu. The main motivation of migration was to seek a job in urban areas. The occupation at the place of destination were factory workers, employee at company, students, salesmen, farmers and public officials in that order.

• Communications for Statistical Applications and Methods
• /
• v.27 no.3
• /
• pp.385-395
• /
• 2020

We present a new maximum likelihood approach to estimate demographic history using genomic data sampled from two populations. A demographic model such as an isolation-with-migration (IM) model explains the genetic divergence of two populations split away from their common ancestral population. The standard probability model for an IM model contains a latent variable called genealogy that represents gene-specific evolutionary paths and links the genetic data to the IM model. Under an IM model, a genealogy consists of two kinds of evolutionary paths of genetic data: vertical inheritance paths (coalescent events) through generations and horizontal paths (migration events) between populations. The computational complexity of the IM model inference is one of the major limitations to analyze genomic data. We propose a fast maximum likelihood approach to estimate IM models from genomic data. The first step analyzes genomic data and maximizes the likelihood of a coalescent tree that contains vertical paths of genealogy. The second step analyzes the estimated coalescent trees and finds the parameter values of an IM model, which maximizes the distribution of the coalescent trees after taking account of possible migration events. We evaluate the performance of the new method by analyses of simulated data and genomic data from two subspecies of common chimpanzees in Africa.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.11
• /
• pp.4597-4601
• /
• 2015

Background: Macrophage migration inhibitory factor (MIF) -173G/C (rs755622) gene polymorphism has been associated with cancer risk. Previous studies have revealed that MIF -173G/C gene polymorphism may increase cancer in the Chinese population, while results of individual published studies remain inconsistent and inconclusive.We performed this meta-analysis to derive a more precise estimation of the relationship. Materials and Methods: We conducted a search on PubMed, Embase, MEDLINE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), Wanfang, Weipu on Dec 31, 2014.Odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the association. A total of eight studies including 2,186 cases and 2,285 controls were involved in this meta-analysis. Results: The pooled results indicated the significant association between MIF -173G/C polymorphism and the risk of cancer for Chinese population (CC + CG vs GG: OR=1.14, 95%CI=1.02-127, pheterogeneity<0.01; P=0.023; CC vs CG+GG: OR=1.12, 95%CI=1.02-1.23, pheterogeneity<001; P=0.017;CC vs GG: OR=1.18, 95%CI=1.04-1.33, pheterogeneity<001; P=0.008; CG vs GG:OR=1.03, 95%CI=0.91-1.15, pheterogeneity<001; P=0.656; C vs G:OR=1.24, 95%CI=1.14-1.25, pheterogeneity<001; P<001). Subgroup analysis showed that in patients with "solid tumors", heterogeneity was very large (OR=0.94,95%CI=0.83-1.06,pheterogeneity=0.044; p=0.297). Within "non-solid tumors", the association became even stronger (OR=6.62, 95 % CI=4.32-10.14, pheterogeneity<0.001; p<0.001). Conclusions: This study suggested that MIF -173G/C gene polymorphism may increase increase cancer in the Chinese population.Furthermore, more larger sample and representative population-based casees and well-matched controls are needed to validate our results.

• Journal of the Korean association of regional geographers
• /
• v.22 no.1
• /
• pp.120-134
• /
• 2016

This study aims to investigate the hierarchical stepwise migration and its influences on regions (metropolitan areas, cities and counties of Korea administrative district) through analyzing the city rank-size and the changes of natural increase of population. The result shows that the inter-regional migration has been associated to the decrease of the population and the decline of NIR in the regions where outflows have been persisted. Also, theses demographic events have sequentially occurred through the hierarchy of settlement system: gradually from rural (gun) and lower ranked regions in the system of city rank-size, to urban (si) and regions in the high ranks in the system. Based on the result of this study, it is possible to understand and expect the major origins of inter-regional migration, the presence of the hierarchical stepwise migration and most significantly, the spatial expansion of depopulation problems.

• The Journal of Korean-Japanese National Studies
• /
• no.34
• /
• pp.77-123
• /
• 2018

The liberated korea has the estimated population 16 million in 1945, and added 2.5 million just after an year. The korean repatriates returned by way of 2 main routes. The returnees, Wol-Nam-Min(former residents in north korea), and repatriates from Manchuria came into south korea over the 38th division line. The other repatriates from japanese islands and pacific areas came into Busan port and the vicinity. The repatriates who returned from the China and the Japanese islands made up about 80% of the total added population. However, the influx of overseas repatriates who explosively increased between 1945 and 1946, declined abruptly in April of 1946, and at last illegal re-emigration group to Manchuria and Japan Appeared, who had repatriated from those areas. This study deals with the "re-migration phenomenon of 1946" in korea, mainly focuses on 1) the motivation for those who decided to remigrate, their prospects of resettlement in Manchuria and post war japan after re-migration, 2) the structural problems of the Korean society in 1946-1947, and 3) the social recognition for the people who letf for Manchuria and Japan. This study proved the cause and background of re-migration phenomenon. The Manchuria case, the local authorities wanted farmers and peasants who could cultivate the abandoned land which had been originally pioneered and reclaimed by korean poor peasants, who repatriated to korean peninsula. On the other hand, the korean repatriates had a hard time in tenanting farmland, and so much difficulty in getting farming tools including fertilizer. That's why they left korea for Manchuria again. The Japanese case, the korean repatriates had a tough life owing to the restriction of properties left in japan, while the inflation and food shortage in korea got worse and worst. Accordingly, many koreans tried illegal entrance into post war japan. This study is a part of clarifying the universality and specificity of post war repatriation and migration issues developed in the south Korea. Through this study, we can find how difficult it is for newly liberated areas to accommodate repatriates and make them ordinary nationals in harmonic way with successful social integration. and we can observe the social aspect and administrative ability of newly liberated south korea in detail, Because the present korea has faced with so many problems connected with immigration workers and re-setting with korean communities abroad, we should introspect these historical experience of our own.

• Korea journal of population studies
• /
• v.12 no.1
• /
• pp.74-85
• /
• 1989

Ascertaining the actual growth rate of the population is an issue that has generated a lot of arguments amongst various scholars in the process of determining the actual census count. As such, this has had a pronounced effect in the determination of the actual growth rates for different urban populations in the country. But the effect centres much when it comes to accurately determining the major components or the factors contributing to the rapid growth of urban populations. The problem of rapid population growth centres much on its effects on the available basic social services and amenities provided for the people in these areas. Factors such as levels of medical knowledge and services, nutrition, quantity and quality of housing etc. to some extent influence the quality and duration of lives of the people. As such, their importance cannot be overemphasized when dealing with the issue of population growth. The study aims to examine the rate of population growth in the Federal Capital City, Abuja with respect to the available public provision of basic social services among other objectives. The findings from the data obtained from the Population Survey conducted in the city in 1985 show that the health care facilities available in the capital city are grossly inadequate to serve the entire inhabitants of the city. Moreso, the volume of in-migration into the city also compounds the health problems facing the city. The conclusion is that there is need for more resources to be allocated to the health sector to guarantee adequate and functional health care services in the city.

• Journal of the Korean Geographical Society
• /
• v.36 no.4
• /
• pp.356-381
• /
• 2001

This study has three objectives. One of them is to debate on the incompatible Neo-Malthusianism and Comucopianism, which give us a comparative gauge for analysis of the population elements in Korea and Japan. The other is to investigate how a variety of population elements are related to specific regions, Korea and Japan. And the last is to compare and analyze the residential preference pattems and the degree of care for the future life for the aged over 50 ages. Various elements in population show that Japan is of type superior to Korea, and that the gap between two countries is getting narrow every year. Wiber's migration expectancy is much higher in Kwangiu-si and Chollanam-do than in Hiroshima-ken. Burial customs in funeral ceremony has been vanished in Japan, but only 30 percents in Korea is crematory. This burial customs being much stiff existent in Korea, the effect of the population decrease caused by the death is reduced. A case study through questionnaire on the residential preference patterns for the aged over 50 years old shows that Japanese than Korean are more dependent on their sons and daughters, and ‘loneliness of solitary life’is the first reason in both countries. The degree of care for the future life is also remarkably higher in Japanese than in Korean. These are related in various ways to their ages, scholarships and local areas(si or gun). A general cognition in which the shortage of labour forces comes into existence in aged society is of misconception, because it comes from taking labour forces away from the aged, not from being old society. Even a minute population change is worth notice since the inertia law is also applied to the population phenomenon. Malthusinism hold fairly good even now, and the notion is very important in which population, resources and environmental problems are no longer personal or a regional matters, but the global family's issues.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.6 no.1_2
• /
• pp.49-57
• /
• 1973

Based on the fork length data of 1960 and on the fishery statistical data of 1968, 1970 and 1971, a research was made on the migration of the Pacific saury in the waters off the eastern coast of Korea. The population is divided into four groups in terms of size as shown in Fig. 5. The four groups demonstrate more or less different pattern of migration, both temporally and spatially. Northward migration is brought out in order of size, i. e., the smaller move northward earlier than the larger do, and the order is reverse in the case of southward migration. The migration routes of each size group are presented in Fig. 8. Whether the fish takes its course to the north or the south, its distribution centroid within the fishing grounds is traced in general following the line between $130^{\circ}$ and $130^{\circ}$130^{\circ$x. long., although longitudinally a pronounced annual bias is found in its month position. The moving pattern of the distribution centroid is assumed to be related with the abundance of each group to a considerable extent.

• Land and Housing Review
• /
• v.11 no.1
• /
• pp.21-38
• /
• 2020

This study examined the population movement of the young generation in accordance with the characteristics of housing market focusing on the housing problem of youth issues. Targeting 64 local governments in the seoul metropolitan area, the temporal range was decided as 2015. Setting up the rising population in 19-34 as a dependent variable, supposing that each age group shows different characteristics, it was divided into age groups in 19~34, 19~29, and 25~34. The population movement of the young generation in accordance with the characteristics of housing market was considered through the multiple regression analysis. In the results, the population movement of the young generation was influenced by the change in detached multi-family housing and the rate of housing supply. The increase of detached multi-family housing promoted the population inflow of the young generation while the population movement of the young generation was disturbed by the rising rate of housing supply. Also, when the local characteristics are not controlled, the young generation hesitates to enter the region where relatively high rent should be paid while the new housing supply focusing on apartment is hard to be selected by the young generation for residence because of the size and price. The population movement of the young generation looked quite different in each age group. The population inflow of the young generation in 19~29 was influenced when there were many officetels and non-apartments on top of detached multi-family housing. On the contrary, the population movement of the young generation in 25~34 was significantly influenced by the increase of the whole size of completed apartment area. Even though it was not the research subject of this study, among control variables, the financial independence and daily average number of get-on/off had effects on the movement of the young generation. It means that the housing type preferred by college students and social novices is different from the housing type preferred by the group with experiences in marriage and childbirth within the same young generation. Thus, it would be necessary to divide the purposes of policies for each subject when executing the youth housing policies.