• Journal of Ecology and Environment
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• v.38 no.4
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• pp.493-503
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• 2015

This study analyzed how spatial distribution of Himantormia lugubris is affected by the microenvironment in the Antarctic Specially Protected Area (ASPA) No. 171 located in the Barton Peninsula of King George Island that belongs to the maritime Antarctic. In order to determine the population structure of H. lugubris growing in Baekje Hill within ASPA No. 171, we counted the individuals of different size groups after dividing the population into 5 growth stages according to mean diameter as follows: ≤ 1 cm, 1-3 cm, 3-5 cm, 5-10 cm, and ≥ 10 cm. The count of H. lugubris individuals in each growth stage was converted into its percentage with respect to the entire population, which yielded the finding that stages 1 through 5 accounted for 32.8%, 25.3%, 15.9%, 22.5%, and 3.5%, respectively. This suggests that the population of H. lugubris in ASPA No. 171 has a stable reverse J-shaped population structure, with the younger individuals outnumbering mature ones. The mean density of H. lugubris was 17.6/0.25 m², mean canopy cover 13.3%, and the mean dry weight 37.8 g/0.25 m². It began to produce spore in the sizes over 3 cm, and most individuals measuring 5-10 cm were adults with sexually mature apothecia. The spatial distribution of H. lugubris was highly heterogeneous. The major factors influencing its distribution and performance were found to be the period covered by snow, wind direction, moisture, size of the substrate, and canopy cover of Usnea spp. Based on these factors, we constructed a prediction model for estimating the spatial distribution of H. lugubris. Conclusively, the major factors for the spatial distribution of H. lugubris were snow, wind, substrate and the competition with Usnea spp. These results are important for understanding of the distribution in the maritime Antarctic and evolution of H. lugubris that claims a unique life history and ecological niche.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.259-266
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• 1993

This experiment was carried out to the effect of population densities on the growth reproduction, cast production of the earthworm and chemical composition of worm casts. The population densities of 50, 100, 150, 200 and 250 individuals of the earthworm fed with cow manure was studied in rearing box($6,400cm^3$) and fertility stage during a period of 60 days. The results were summarized as follows 1. Survival rates(SR) of the earthworms had significantly positive correlated with increasing rate(IR). But, survival rates(SR) and increasing rate(IR) had significantly negative correlated with reproductive efficiency(RE). 2. The ranges of optimum population densities estimated were $42.7cm^3-128.0cm^3/worm$. 3. The cast production estimated were 36.5mg-80.9mg/day/worm grown in optimum population densities(50-150 worms/$6,400cm^3$). 4. The earthworm castings are an excellent soil conditioning material with a high chemical composition and their physical properties.

• Korean Journal of Plant Taxonomy
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• v.53 no.1
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• pp.1-8
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• 2023

Sustainable habitats play a significant role in determining the survival and habitat preservation of endangered species. To conserve the endangered species Iris dichotoma Pall. and its habitat in Taeanhaean National Park, we collected seeds from a natural population and germinated and propagated them in a greenhouse. In 2019, the propagated individuals of I. dichotoma were transplanted at two study sites in Taeanhaean National Park. After conservation translocation, annual monitoring was conducted from 2020 to 2022, and factors related to the survival and growth of I. dichotoma (clonal propagation rate [%], the flowering rate [%], the population density [individual/m²], the maximum leaf bundle length [height; cm], the maximum leaf bundle width [cm], and the pedicel length [cm]) were measured. According to the results of the monitoring of the flowering and fruiting periods for three years after transplantation, 82.4% of individuals in total were found to have survived. During 2020 to 2022, the mean population density (individual/m²) increased from 0.36 to 0.42 and the size of the leaf bundle length and the width both decreased compared to the corresponding figures in 2019 (p < 0.05). According to the findings here, the transplanted population of I. dichotoma is considered to have adapted successfully to its new site in Taeanhaean National Park.

• Korea journal of population studies
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• v.18 no.2
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• pp.70-97
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• 1995

The main purpose of this paper is to analyze the trend of urbanization and population distribution in North Korea. Although North Korean data lack comparable details, attention has been given to the comparison of urban system between North and South Korea. In North Korea, the pace of urbanization was most rapid just after the Korean War, from 1954 to 1960. However, the pace slowed down markedly in the early 1970s and has remained sluggish since then. North Korea is currently much less urbanized than South Korea. As specific features of urbanization in North Korea, emergence of new cities along inland borders, prominence of intermediate-sized cities, and sudden population growth of major cities due to boundary expansion are stressed. Available demographic data also indicate an overwhelming primacy of Pyongyang Municipality in the urban system, and rapid growth of satellite cities in the west-central region. It appears that, in North Korea, urbanization process has been a product of the government's development policies rather than individual's socioeconomic motivation to migrate urbanward. Finally, migration issues after unification of the Korean Peninsula and related problems are discussed in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.94-98
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• 1982

To understand the growth pattern of ginseng plant under shading, the vertical distribution of leaf area, leaf area index (LAI) and specific leaf weight (SLW) and changes in light intensity as affected by planting position were investigated in 3 to 5 years old ginseng plant populations. Light intensity was vertically lowest at about 10cm above the ground and became low at the rear planting position in 3-year-old population. When culturing bed (96cm in width) were divided into three parts at intervals of 32cm from front to rear, the leaf area in 3-year-old population was largest in middle 1/3 part of planting bed. Light intensity affected the SLW positively, but LAI showed no distinct difference among planting positions. The light environment of 4-year-old population was worse than that of 3-year-old population and leaf area and LAI differed greatly among planting positions. In 5-year-old population, leaf dry weight and leaf area of furrow part (that is, the amount of leaves protruded from the plants which were planted in 1st, 2nd or 3rd lines into the furrow) increased. The dry weights of leaves and stem increased considerably as plant became aged, and were distributed mainly in upper layer.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.141-147
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• 2000

This study was carried out to investigate the population changes of Liriomyza trijolii (Burgess) on chrysanthemum and its relationship to plant growth and damages. In spring culture of chrysanthemum, L. trifolii adults begun to be attracted by the yellow sticky trap from early May and maintained high population until the middle of July. Larval density increased gradually from late May and reached peak in early July. In autumn culture, the population density of adult was lower than that of spring culture but the number of adult was great in late September and the middle of October. This trend was similar to that of larval stage. Damaged leaves by larva could be found from 4 weeks after transplanting and its rate was low until 5 weeks but increased abruptly after 6 weeks and maintained 70% level until flowering stage in spring culture. Damaged leaves increased with plant growth in some varieties tested in this experiment.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.368-374
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• 2012

BACKGROUND: The urgency of feeding the world's growing population while combating soil pollution, salinization and desertification requires suitable biotechnology not only to improve crop productivity but also to improve soil health through interactions of soil nutrient and soil microorganism. Interest in the utilization of microbial fertilizer has increased. A principle of nature farming is to produce abundant and healthy crops without using chemical fertilizer and pesticides, and without interrupting the natural ecosystem. Beneficial microorganisms may provide supplemental nutrients in the soil, promote crop growth, and enhance plant resistance against pathogenic microorganisms. We mixed beneficial microorganisms such as Bacillus sp. Han-5 with anti-fungal activities, Trichoderma harziaum, Trichoderma longibrachiatum with organic material degrading activity, Actinomycetes bovis with antibiotic production and Pseudomonas sp. with nitrogen fixation. This study was carried out to investigate the mixtures on the soil microflora and soil chemical properties and the effect on the growth of lettuce and cucumber under greenhouse conditions. METHODS AND RESULTS: The microbial mixtures were used with each of organic fertilizer, swine manure and organic+swine manure and compared in regard to changes in soil chemical properties, soil microflora properties and crop growth. At 50 days after the treatment of microorganism mixtures, the pH improved from 5.8 to 6.3, and the EC, $NO_3$-Na and K decreased by 52.4%, 60.5% and 29.3%, respectively. The available $P_2O_5$ and $SiO_2$ increased by 25.9% and 21.2%, respectively. Otherwise, the population density of fluorescent Pseudomonas sp. was accelerated and the growth of vegetables increased. Moreover, the population density of E. coli and Fusarium sp., decreased remarkably. The ratio of bacteria to fungi (B/F) and the ratio of Actinomycetes bovis to fungi (A/F) increased 2.3 (from 272.2 to 624.4) and 1.7 times (from 38.3 to 64), respectively. Furthermore, the growth and yield of cucumber and lettuce significantly increased by the treatment of microorganism mixtures. CONCLUSION(S): These results suggest that the treatment of microorganism mixtures improved the chemical properties and the microflora of soil and the crop growth. Therefore, it is concluded that the microorganism mixtures could be good alternative soil amendments to restore soil nutrients and soil microflora.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.188-193
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• 1998

The authors examined the variations of environmental factors, the distributions of cyanobacteria, heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica according to development and extinction of cyanobacterial bloom at a site in Daechung Dam reservoir. And certified the relationship between each other. Water temperature variated in a typical pattern. pH and concentrations of dissolved oxygen and chlorophylla was high in bloom period, and lowered with the decline of bloom. Phosphorus played as a growth-limiting factor at this study site. Total nitrogen concentration increased during blooming period, which indicated that nitrogen has been fixed by aquatic organisms such as cyanobacteria. Cyanobacteria distributed from June 17, and such cyanobacterial species as Anabaena spp., Aphanizomenon spp., Microcystis spp., Oscillatoria spp. and Phormidium spp. was detected during study period. Anabaena spp. distributed relatively highly distributed from July 23 to September 22, and disappeared completely at September 29. Heterotrophic bacterial and cyanobacterial populations varied inverse-proportionally. There was a relevancy between the variations of Anabaena spp., heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica. Microorganisms that inhibit the growth of Anabaena cylindrica distributed from early growth phase of Anabaena spp. population to immediately after the extinction of Anabaena spp. With the population of Anabaena cylindrica growth-inhibiting microorganisms decreasing, increases of heterotrophic bacterial population followed it. Thease results indicate that microorganisms have a part in the extinction of cyanobacterial bloom, especially at its destroying period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.567-577
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• 1996

This study is to estimate population ecological parameters, including growth parameters, survival rates, instantaneous coefficients of natural and fishing mortalities, and age at first capture, as well as growth rates at age of the hairtail, Trichiurus lepturus Linne in Korean waters. For describing the growth of the hairtail, three growth models were fitted, and the von Bertalanffy growth model was adopted for the purpose of the further stock assessment work. The von Bertalanffy growth parameters estimated from a nonlinear regression using EXCEL Solver were $L_\infty=46.01cm$, K=0.3868, and $t_0=-0.3220$. Annual survival rate (S) of the hairtail was estimated to be 0.277 (variance=0.00035) and the instantaneous coefficient of natural mortality (M) was estimated to be 0.441/year. Instantaneous coefficient of fishing mortality (F) for the recent years was calculated as 0.843/year, implying an impact from fishing about two times greater than that of natural mortality. The age at first capture $(t_c)$ was estimated to be 0.787 years, which is much younger age than $50\%$ mature age. Finally, the growth rates at age were estimated.

• Journal of Korean Academy of Nursing
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• v.5 no.1
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• pp.112-132
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• 1975

When Korean family planning services began as a part of the National Policy in 1962, the annual population growth was 3.0%. This growth rate has been decreased to 2.0% during last ten year period. And it seems imperative that all hospitals, as well as related organizations, should participate in family planning in order to contribute to achieving the National goal of 1.5% population growth by 1976, the end of the Third Five Year Economic Development Plan. Nurses should be considered the most important human resources in charge of the core of family planning services in any setting. For the family planning services in the general hospital setting, nurses as a core members contribute much as change agent, motivators, counsellors, educators etc. A nurse can work with patients and their relatives when she is equipped with relevant knowledge and skills. Fur the more family planning cannot be ignored even in hospital setting where more comprehensive nursing care is needed Thus, the general objective of this study is to provide baseline data for better programming of In-service education in family planning so that effective hospital family planning nursing services can be made a part of comprehensive nursing care contributing to the national population program and human welfare. In order to meet the general objective, this study has the following specific objectives : 1. To find out the general characteristics of the clinical nurses working in Y Hospital 2. To evaluate their attitudes and practices of family planning 3. To assess their knowledge, attitudes and practices of population and family planning as professional nurses. 4. To examine and compare data collecting methods for the planning of an In-service Educational Program 5. To explore the contents to be included in this In-service Education Program. The study population randomly selected one hundred nurses working in Y Hospital A cross-sectional survey with questionnaires developed for this study was chosen for the study method. To collect reliable data, the questionnaires were distributed to and answered by the study population in a controlled situation. X²test and t-test was employed in analyzing the data. The findings of this study are as follows: 1. Y Hospital nurses had a lower ideal number of children (X=2.02) and showed no strong preference for male children, and 74% of them expressed the desire to use permanent methods of birth control 2. of this thirty Y Hospital nurses who were married 66.7% stated they were already practicing contraceptive methods. Most of them preferred male methods of contraception. 3. According to objective evaluation about knowledge of various aspects of population and family planning, respondents from collegiate programs significantly knew better the subjects on the average than did respondents from diploma programs of nursing. 4. There was a marked difference in the results of self-evaluation and objective evaluation in their family planning knowledge. It was found that the self-evaluation family planning knowledge seemed to be unreliable. Accordingly, the objective test methods appeared to be more reliable in the evaluation of knowledge levels. 5. The subject areas needed to be included in In-service education for the Hospital family planning services in Y Hospital are 1) rhythm methods, 2) tubal-legation, 3) family planning effects of contraceptives, 4) population growth, 5) demographic traction, 6) population structure and 7) infant mortality facts. In addition, 1) various oral contraceptives, 2) basal temperature method, 3) laparoscopic female sterilization, 4) interfering factors of family planning, 5) anatomy and physiology of the female reproductive organs were additional areas to be taught to respondents from 3-year diploma schools of nursing. Demographic transition was one subject area in which the four-year graduates need further study. 6. Population problems guidance and counselling in family planning instruction in the theory and practice of contraceptives should be included in future In-service Education Programs in order to provide more effective hospital Family Planning Services, stated 77.0% of the respondents.