• Parasites, Hosts and Diseases
• /
• v.59 no.2
• /
• pp.121-129
• /
• 2021

We aimed to explore the population dynamics of snail in 3 sites of the White Nile in Sudan. More specifically, we aimed to investigate the annual patterns of snail populations that act as intermediate hosts of schistosomes and monthly snail infection rates and ecological characteristics presumably related to snail populations. We collected snails for 1 year monthly at 3 different shore sites in the vicinity of El Shajara along the White Nile river in Khartoum State, Sudan. In addition, we measured air and water temperatures, water turbidities, vegetation coverages, and water depths and current speeds. Most of the collected snails were Biomphalaria pfeifferi and Bulinus truncatus. The population densities of snails and their infection rates varied across survey sites. The collected snails liberated S. mansoni and S. haematobium cercariae as well as Amphistome and Echinostome cercariae. Infected snails were found during March-June. The ecological characteristics found to be associated with the absence of snails population were: high turbidity, deep water, low vegetation coverage (near absence of vegetation), high water temperature, and high current speed. To our knowledge, this is the first longitudinal study of the snail population and ecological characteristics in the main basin of the White Nile river.

• Journal of the Korean Institute of Rural Architecture
• /
• v.23 no.2
• /
• pp.9-16
• /
• 2021

The purpose of this study is to maintain the existing characteristics of the city by utilizing the physical decline status and floating population in small and medium cities residential areas. In addition, it intends to present the direction of flexible urban regeneration and maintenance by reflecting regional characteristics and current status. A total of three data were used in this study. Building data, floating population data, and census output area data were used. Building data and floating population data were classified into five classes. The graded data were joined to the census output area data and analyzed by overlapping the two data. As a result of analysis of 17 residential areas in 5 small and medium cities in Jeollanam-do, 4 types, 2 management models, and 4 indicators could be presented by grade and regional characteristics. This study is meaningful in that it is possible to plan regionally customized urban regeneration/maintenance management plans and projects through the typology of the current status and characteristics of the region, which is an important step in the bottom-up form.

• Korea journal of population studies
• /
• v.19 no.2
• /
• pp.77-105
• /
• 1996

The rural problems which we are facing start from the extremely small sized population and the skewed population structure by age and sex. Thus we analyzed the change of the rural population. And we analyzed the recent return migration to the rural areas by comparing the recent in-migrants with out-migrants to rural areas. And by analyzing the rural village survey data which was to show the current characteristics of rural population, we found out the effects of the in-migrants to the rural areas and predicted the futures of rural villages by characteristics. The changes of rural population composition by age was very clear. As the out-migrants towards cities carried on, the population composition of young children aged 0~4 years was low and the aged became thick. The proportion of the population aged 0~4 years was 45.1% of the total population in 1970 and dropped down to 20.4% in 1995, which is predicted to become under 20% from now on. In the same period(1970~1995), the population aged 65 years and over rose from 4.2% to 11.9%. In 1960, before industrialization, the proportion of the population aged 0~4 years in rural areas was higher than that of cities. As the rural young population continuously moves to cities it became lower than that in urban areas from 1975 and the gap grew till 1990. But the proportion of rural population aged 0~4 years in 1995 became 6.2% and the gap reduced. We can say this is the change of the characteristics of in-migrants and out-migrants in the rural areas. Also considering the composition of the population by age group moving from urban to rural area in the late 1980s, 51.8% of the total migrants concentrates upon age group of 20~34 years and these people's educational level was higher than that of out-migrants to urban areas. This fact predicted the changes of the rural population, and the results will turn out as a change in the rural society. However, after comparing the population structure between the pure rural village of Boeun-gun and suburban village of Paju-gun which was agriculture centered village but recently changed rapidly, the recent change of the rural population structure which the in-migrants to rural areas becomes younger is just a phenomenon in the suburban rural areas, not the change of the total rural areas in general. From the characteristics of the population structure of rural village from the field survey on these villages, we can see that in the pure rural villages without any effects from cities the regidents are highly aged, while industrialization and urbanization are making a progress in suburban villages. Therefore, the recent partial change of the rural population structure and the change of characteristics of the in-migrants toward rural areas is effecting and being effected by the population change of areas like suburban rural villages. Although there are return migrants to rural areas to change their jobs into agriculture, this is too minor to appear as a statistic effect.

• Journal of Korean Society of Rural Planning
• /
• v.25 no.4
• /
• pp.99-107
• /
• 2019

This paper analyzed the characteristics of population change from 2000 to 2018 in 466 mountainous areas using resident registration data from the Ministry of the Interior and Safety, and projected the population in those areas through 2050 with the cohort change ratio method. The population had dramatically decreased from 2000 to 2009. With the slowing population decrease after 2010, the population has increased gradually since 2014. Especially the population of ages over 65 in 2018 had increased 34% compared to 2000, while the working age population had decreased 29%. This shows that population aging becomes serious problems in the mountainous area. Assuming the cohort change ratios from 2010 to 2015 and child-woman ratio in 2015 remain constant, it appeared that the projected population of the mountainous area dropped to 1.26 million in 2030 and 820,000 in 2050. It is expected to have a population with an inverted pyramid structure showing a gender imbalance with more females in 60's and 70's. Although it continues to show the recent population growth in mountainous area, population in mountainous area is expected to consistently decrease. Therefore, it is required to develop policies and strategies to promote an influx of people into mountainous area for maintaining functionality and sustainability of mountainous areas.

• Korean Journal of Ichthyology
• /
• v.22 no.4
• /
• pp.249-255
• /
• 2010

Ecological characteristics of landlocked and anadromous populations of Hypomesus nipponensis were investigated from December 2008 to April 2009 in the Soyangho (landlocked population) and Hyangho (anadromous population). Morphological differences between the landlocked and anadromous populations were not found. The spawning season was March in the Soyangho and late February in the Hyangho. Individuals of both populations were sexually mature at sizes over 60 mm total length. Gonadosomatic index of the landlocked population (female: 20.5%, male: 3.7%) was higher than in the anadromous population (female: 17.4%, male: 3.3%). Number of eggs in the ovaries was greater in the anadromous Hyangho (7,325) population and fewer in the Soyangho (4,902) population; this corresponded to the greater total length in the former. Condition factor was 0.6 (0.49~0.74) in the Soyangho population and 0.7 (0.47~0.76) in the Hyangho population. Stomach contents of H. nipponensis consisted mainly of zooplankton and aquatic insects, and the size of prey was larger in the Hyangho population than in the Soyangho population.

• Korea journal of population studies
• /
• v.24 no.2
• /
• pp.117-147
• /
• 2001

The main purpose of this paper is to analyze sex and age composition of the 1994 North Korean census data. First this paper describes the background information concerning the first population census ever taken in North Korea since the separation of the North and South. It utilizes the available data to explain the trend and current population status of North Korea. The focus of this research is to point out and analyze the problems in the sex and age composition of the North Korean census data. One of the most striking characteristics of the census data is that an enormous portion of the young male population was excluded from the census counts. Such omissions are strongly suggested by a incredible drop in sex ratios for the age groups of 16 to 25. In addition, the total sum of the population by age groups turns out to be substantially smaller than the total sum of the population by geographical regions. The total discrepancy amounts to 691 thousand. Along with sex ratios and age ratios, Myers indices, UN age-sex accuracy indices, indices of relative difference, and indices of dissimilarity are calculated to analyze the characteristics and accuracy of sex and age composition in the North Korean census data. Finally, this paper readjusts the sex and age composition of the 1994 census data, and attempts to produce a more accurate population of North Korea.

• Journal of Ecology and Environment
• /
• v.38 no.2
• /
• pp.195-211
• /
• 2015

The objectives of this research were to determine mean and maximum tolerance ranges of Carassius auratus ($C_a$) and Cyprinus carpio ($C_c$) populations on various physico-chemical parameters and ecological indicator metrics. Little is known about chemical tolerance ranges of the two species, even though these species are widely distributed species in aquatic ecosystems. Maximum tolerance ranges of $C_a$-population to total nitrogen (TN) and total phosphorus (TP) were $20.3mgL^{-1}$ and $2.0mgL^{-1}$, respectively. Optimal ranges of TN and TP in the $C_a$-population were $1.7-5.0mgL^{-1}$ and $0.06-0.30mgL^{-1}$, respectively. Such nutrient regimes of the $C_a$-population were evaluated as hypereutrophy, indicating high tolerance limits. The $C_c$-population had similar ecological characteristics to $C_a$-population, but the mean tolerance ranges of TN, TP, BOD, and COD were significantly (p < 0.05) greater than the $C_a$-population. Ecological patterns of trophic composition and tolerance guilds in the $C_a$-population were similar to those of the $C_c$-population. The model value of Index of Biological Integrity (IBI) of the habitat where C. auratus and C. carpio co-occurred averaged $15.0{\pm}4.3$ and $12.9{\pm}3.6$, respectively. Based on the modified criteria of the United States Environmental Protection Agency (Klemm et al. 1993), it indicated poor ecological health of both species. These results suggest that both species are highly tolerant to chemical and physical habitat conditions of waterbodies, and that the chemical tolerance range of $C_c$-population was higher than $C_a$-population.

• Journal of Fashion Business
• /
• v.18 no.4
• /
• pp.153-167
• /
• 2014

In this study, changes in the timing of puberty physicality and mentality and beauty characteristics of high school students were characterized for high school students and the general high school population in order to distinguish between interest and beauty and beauty products and beauty behavior for comparative analysis. First, for beauty characteristics of high school students and the general high school population, differences in beauty action and beauty characteristics of high school students were higher than this beauty behavior. Secondly, for the high school students and high school beauty characteristics of general high school population for beauty and beauty products, the difference between interest and multi-functional beauty products that characterize high school students has beauty and beauty products with multi-functional beauty products interest being high. Third, high school students and high school beauty characterize the general high school population of beauty is different from behaviors on its factors with common factors including the psychological gratification 'for reasons of appearance management looks for reasons that do not' have time to manage the response. Two groups of factors that characterize the differences in appearance and beauty as areason to manage high school students interested in the 'style' order, high school students do not manage reasons for lack of interest in the 'general' as a response. Beauty characteristics of high school students in the beauty, beauty products, and products demonstrated a multi-functional information gathering with lots of attention, and much ability can have an active beauty behavior. The general high school population lacks the ability to gather information in accordance with interested beauty behavior being passive. The two groups and beauty behavior patterns of consumption could see that a difference occurred.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.26 no.4
• /
• pp.173-187
• /
• 2023

In an era of population decline, depopulated regions facing challenges in attracting inbound population migration must enhance urban vitality through the attraction of living populations. This study focuses on Busan, a city experiencing population decline, comparing the spatiotemporal distribution characteristics of registered residents and living populations in various administrative districts (Eup-Myeon-Dong) using mobile communication big data. Administrative districts are typified based on population change patterns, and regional characteristics are analyzed using indicators related to urban decline and vitality. Spatiotemporal distribution analysis reveals generally similar density patterns between registered residents and living populations; however, a distinctive feature is observed in the city center areas where the density of registered residents is low, while the density of living populations is high. Divergent trends in spatial patterns of change between registered residents and living populations show clusters of registered population decline in low-density areas and clusters of living population decline in high-density areas. Areas adjacent to declining living populations exhibit large clusters of population changes, indicating a spillover effect from high-density to neighboring areas. Typification results reveal that, even in areas with a decline in registered residents, there is active population influx due to commuting or visiting. These areas sustain an increase in the number of businesses, confirming the presence of industrial and economic growth. However, approximately 47% of administrative districts in Busan are experiencing a decline in both registered residents and living populations, indicating ongoing regional decline. Urgent measures are needed for enhancing urban vitality. The study emphasizes the necessity of utilizing living population data as an urban planning indicator, considering the increasing limit distance of urban activities and growing interregional interaction due to advancements in transportation and communication.

• Journal of Cadastre & Land InformatiX
• /
• v.49 no.1
• /
• pp.123-144
• /
• 2019

The purpose of this study is to grasp factors the increasing population growth rate of the region through the regional and housing market characteristics. This paper has used multiple regression as the dependent variable (average of the population growth rate of 85cities during the last five years) and the independent variables analyzed the regional and housing market characteristics on the average. The results of the analysis, The regional and housing market variables that have had a significant impact on the regional population growth rate over the last five years are birth rate, employment rate, production available population growth rate, apartment rate, resale rights rate, and apartment turnover rate and the number of businesses per thousand and has decreased. In other words, The regions where the population increased by region for the last five years were the ones with the transfer of public institutions (innovation cities) and land development among the Seoul metropolitan area and non-Seoul metropolitan area excluding Seoul and metropolitan cities. The results of this study is intentional to suggest Policy point of view for the balanced regional development presented at the government level for other the metropolitan area, such as the small and medium cities that are undergoing population decline.