• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.3
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• pp.223-232
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• 1998

The main experiment related to this report was undertaken to assess the effects of two rates of $Ca(OH)_2$ (0, 250 kg/10a only at establishment) and five rates of $N-P_20_5-K_20$ (0-0-0, 0-10-10, 6-15-15, 12-20-20, 24-25-20 kg/10a/year) on the pasture establishment, forage yield and quality, and vegetation etc. After this 10-year main e experiment pasture had been used to assess the effects of the above treaments on the soil characteristics in oversown hilly pasture of a grass-clover sward. soil properties of mutual ratios of exchangeable cations at d different soil depth, and the visible characteristics of soil conservation obtained are summarized as follows; 1. Compared with the properties of soil fertility and the level for the likelihood grass tetany, the mutual ratios of exchangeable cations in soils; Ca:Mg:K(% of CEC), Ca:Mg:K(K=I), $K/\sqrt{Ca+Mg}$, Mg/K, K/Mg, and Ca/Mg, were discussed at different soil depth. Before and after experiment, these ratios were generally unbalance and unsuitable, and were rather worsened in the order of Mg>Ca>K under the conditions of liming and NPK fertilization without Mg. 2. The ratios of Ca and Ca/Mg were increaby liming, whereas it of $K/\sqrt{Ca+Mg}$ was redused. The ratios of K and $K/\sqrt{Ca+Mg}$ in control and the heavy fertillization of NPK(especially N) were rather lowered than those in the low and medium fertilizations of NPK. 3. The prperties of consevation were closely related with the forage productivity/vegetation rates, as affected by liming and the application rates of NPK. In control of NPK, It was shown to be the worst soil conservation; severly eroded(3rd grade), exporsure of subsoil, redish brown in soil colour, and 18.8% of cobble and stony in covering rate. 4. The improvement of soil conservation was greatly enhanced by increasing the NPK rate. In the medium and heavy fertilizations of NPK, it was shown to be the favorable improvement of soil conservation; slightly eroded(lst grade), covered with humus layer/grass residues in surface soil, dark brown in surface soil colour, under 1% of cobble and stony in covering rate. The increasing of legume yield/vegetation rate by liming rather enhanced the soil conservation of grassland.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.568-578
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• 2019

The nymphal development of the potato aphid, Macrosiphum euphorbiae (Thomas), was studied at seven constant temperatures (12.5, 15.0, 17.5, 20.0, 22.5, 25.0, and 27.5±1℃), 65±5% relative humidity (RH), and 16:8 h light/dark photoperiods. The developmental investigation of M. euphorbiae was separated into two steps, the 1^st through 2^nd and the 3^rd through 4^th stages. The mortality was under 10% at six temperatures. However, it was 53.0% at 27.5℃. The developmental time of the entire nymph stage was 15.5 days at 15.0℃, 6.7 days at 25.0℃, and 9.7 days at 27.5℃. In the immature stage, the lower threshold temperature of the larvae was 2.6℃ and the thermal constant was 144.5 DD. In our analysis of the temperature-development experiment, the Logan-6 model equation was most appropriate for the non-linear regression models (r²=0.99). When the distribution completion model of each development stage of M. euphorbiae larvae was applied to the 2-parameter and 3-parameter Weibull functions, each of the model's goodness of fit was very similar (r²=0.92 and 0.93, respectively). The adult longevity decreased as the temperature increased but the total fecundity of the females at each temperature was highest at 20℃. The life table parameters were calculated using the whole lifespan periods of M. euphorbiae at the above six temperatures. The net reproduction rate (R₀) was highest at 20.0℃(63.2). The intrinsic rate of increase (r_m) was highest at 25℃(1.393). The finite rate of doubling time (D_t) was the shortest at 25.0℃(2.091). The finite rate of increase (λ) was also the highest at 25.0℃(1.393). The mean generation time(T) was the shortest at 25.0℃(9.929).

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.349-354
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• 1974

Survey results concerning the general information on health status of 7,050 inhabitants (1,141 households) which have been selected within Keumsan Gun, Chung Choung Nam Do area are as follws: 1. The average family size is $6.18{\pm}2.17$ persons per household. Tertiary sex ratio is 105.5 population composition of Kumsan Gun shown a pyramidal form consisting of 51.6% of the inhabitants under 20 years of age. 2. Rate of illiteracy amounts to 12.1% and only 4.1% of villagers were graduated from high schools, 80% of the inhabitants have some kind of jobs: 46.1% of them are engaged in agriculture, 95.2% of villagers have their own houses, and remaining 4.8% do not have their own. 3. 72% of households made use of health services provided provided by health centre or subcentres during a period of 1 year from April 1, 1973 to March 31, 1974. 26.8% of them visited health centre of sub-centres 2-4 times annually for the following purposes: 1) Vaccination: 35.7% 2) Diagnosis or treatment: 26.7% 3) Family planning: 24.1% 4) Maternal and child health: 10.5% 4. Utilization rate of health facilities is on an average 4.4 times per household and 0.75 times per capita. 5. Birth rate in the area is 1.91% and death rate is 0.75%, indicating the natural increase rate is only 1.16% that is lower than the nationwide rate of 1.8-2.2% in 1970 and 1.5-1.9% in 1973. 6. 37.7% of fertile women (20-40 years old) in the area are still unmarried, Fertility rate is the highest in the age group of 63-40 years old showing a value of 17.1%. 7. The unmarried population in this area amounts to 61.4% : 61.4% in male and 57.6% in female. 8. Number of inhaibtants who practice family planning is 612 persons(22.6%) among the married (2.771). This value consists of 8.3% of married males and 34.8% of married females. Only 16.0% of the people who put family planning in practice undergo permanent contraceptive methods and remaining 84.0% of them do temporary measures. 9. Only 57.7% of the subjects took vaccinations as follows: 1) B.C.G. vaccination: 82.7% 2) D.P.T. vaccination: 76.2% 3) Poliomyelitis vaccination: 67.9% 4) Smallpox vaccination: 62.6% 10. In the utilization of medical facilities in case of sickness drug stores (32.15%) comes first and hospitals or clinics (28.65%), health centre of health sub-centres (17.96%), herb drug stores (7.36%) and herb gerneral practioners (6.31%), etc., in decreasing order. Sickness that people living in this area suffer from are neuralgia, disease digestive troubles, respiratory diseases and skin lesions, etc.

• Korean Journal of Environment and Ecology
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• v.21 no.6
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• pp.544-553
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• 2007

This study is focused on the cultivation of seedlings and cuttings of roundleaf chastetree(Vitex rotundifolia L. f.) according to the sorts of soil and fertilization methods. The results are summarized as follows: When roundleaf chastetree seedlings(aged 1-0) and cuttings(aged 1-0) were cultivated in three different kinds of soil- sand, granite soil, and yellow silt- without any fertilization, 70% of the seedlings survived in sand and granite soil, and 35% did in yellow silt; 90% of the cuttings survived in granite soil and 80% did in sand and yellow silt. The general growth of both seedlings and cuttings was good in granite soil, and sand but relatively inferior in yellow silt. Seedlings showed good stem growth while cuttings had fine root growth. In case of cultivation of seedlings with different kinds and quantities of fertilizer adjusted and with granite soil as basic soil, seedlings and cuttings survived in the experimental section where only the organic fertilizer was used as basic fertilization; in contrast, seedlings grown in the experimental section were all dead where both inorganic and liquefied fertilizer were used. Cuttings showed considerably higher survival rates than seedlings at the experimental fertilization section; particularly, the survival rate of cuttings was twice as much as that of seedlings at the experimental section with low fertilization. This study results revealed that cuttings are desirable than seedlings in general rootage, growth, adaptability to soil, and cuttings have lower demand for soil fertility in time of growing roundleaf chastetree saplings.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.291-295
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• 2019

BACKGROUND: Mixed cropping of hairy vetch and Barley is widely used as a green manure for reducing chemical fertilizers while maintaining soil fertility in paddy soil. We investigated the effect of Molybdenum (Mo) fertilizer on vetch N₂ fixation, biomass production and transfer N from vetch to barley under a hairy vetch-barley mixed cropping system. METHODS AND RESULTS: The barley and hairy vetch were sowed at a rate of 135 and 23 kg/ha, respectively, without chemical fertilizer application but with Mo fertilizer at 0, 0.5, 1.0, 2.0, and 4.0 kg/ha as a treatment. The percentage of hairy vetch N derived from air N₂ fixation (%Ndfa) and N transfer from hairy vetch to barley (%Ndfv) was determined by the ¹⁵N natural abundance method. Although application of Mo at 2.0 kg/ha significantly increased biomass of both barley and hairy vetch, the biomass was decreased at application of Mo 4.0 kg/ha. At the application of Mo 2.0 kg/ha, the percentage of Ndfa and Ndfv was 81.7 and 53.9, respectively, which are significantly higher than that of the treatments without Mo. CONCLUSION: These results highlight that application of Mo fertilizer can be an effective measures to improve N fixation in hairy vetch and biomass production in both barley and hairy vetch.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.4
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• pp.207-213
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• 2017

Objective: This study investigated the prevalence of infections with human papillomavirus, Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, and Mycoplasma genitalium in the semen of Korean infertile couples and their associations with sperm quality. Methods: Semen specimens were collected from 400 men who underwent a fertility evaluation. Infection with above five pathogens was assessed in each specimen. Sperm quality was compared in the pathogen-infected group and the non-infected group. Results: The infection rates of human papillomavirus, C. trachomatis, U. urealyticum, M. hominis, and M. genitalium in the study subjects were 1.57%, 0.79%, 16.80%, 4.46%, and 1.31%, respectively. The rate of morphological normality in the U. urealyticum-infected group was significantly lower than in those not infected with U. urealyticum. In a subgroup analysis of normozoospermic samples, the semen volume and the total sperm count in the pathogen-infected group were significantly lower than in the non-infected group. Conclusion: Our results suggest that infection with U. urealyticum alone and any of the five sexually transmitted infections are likely to affect sperm morphology and semen volume, respectively.

• The Korean Journal of Applied Statistics
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• v.28 no.4
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• pp.663-683
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• 2015

The change of the population pyramid due to low fertility and rapid aging threatens the financial sustainability of National Health Insurance. We construct statistical models for prevalence rates and medical expenses using National Health Insurance Service (NHIS) sample cohort data from 2002-2013. We then project yearly expenditures and income of national health insurance until 2060 that considers various assumptions in regards to future population structure and economic conditions. We adopt a VECM-LC model for prevalence rates and the double exponentially smoothing method for the per capita co-payment of healthcare expense (in which the two models are institution-disease-sex-age specific) to project of national health insurance expenditures. We accommodate various assumptions of economic situations provided by the national assembly and government to produce a financial projection for national health insurance. Two assumptions of dependents ratios are used for the projection of national health insurance income to conduct two future population structures by the two assumptions of aging progresses and various assumptions on economic circumstances as in the expenditure projection. The health care deficit is projected to be 20-30 trillion won by 2030 and 40-70 trillion won by 2060 in 2015 constant price.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.33-40
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• 2010

In this study, the production of transgenic goats using sperm to integrate exogenous DNA and artificial insemination (AI) was carried out and the technical protocols for sperm-mediated gene transfer (SMGT) in the goat were optimized. The standard sperm parameters and the ability to bind foreign genes were assessed to select suitable sperm donor bucks. A total of 134 oestrous does were divided into 4 groups and inseminated using different methods and sperm numbers. The does of Groups I to III were inseminated with fresh semen ($1-2\times10^{7}$ and $10^{6}$ sperm) or frozen-thawed semen ($10^{6}$ sperm), respectively, through conventional intra-cervical AI, and the does of Group IV with frozen-thawed semen ($10^{6}$ sperm) through intrauterine AI. Total genomic DNAs were extracted from ear biopsies of the offspring. The presence of $pEGFP-N_{1}$ DNA was screened by PCR and then by Southern blotting analysis. A total of 76 live kids were produced and 8 kids were tested transgene positive on the basis of agarose gel electrophoresis of the PCR-amplified fragment. Southern blotting analysis of the samples showed 5 positive kids. A transgenic ratio of 10.53% was detected using PCR and 6.58% using Southern blotting. The positive kid rate assayed by PCR and Southern blotting of frozen-thawed goat semen was 3.61% and 9.27% higher than that of untreated semen. The results show that transgenic goats can be produced efficiently by the method of artificial insemination using sperm cells to integrate the exogenous DNA and intrauterine insemination allowed low numbers of DNA-transfected spermatozoa to be used, with satisfactory fertility.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.231-238
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• 2014

BACKGROUND: Biochar (BC) has a great potential for enhancing soil fertility and carbon sequestration while facilitating beneficial waste disposition. Therefore, it is essential to assess and mitigate any inadvertent consequences associated with soil biochar amendment. Earthworm activity is very vital in the soil system, yet there are a limited number of studies that have examined their impact resulting from biochar application to soil. METHODS AND RESULTS: In this study, the survival, growth, reproductive tests, and oxidative DNA damage tests (measured by 8-hydroxydeoxyguanosine (8-OHdG) and catalase (CAT) activities) to assess the potential toxicity to earthworm Eisenia fetida in artificial soil amended with BCs were investigated. The BCs derived from perilla meal, sesame meal, and pumpkin seed were pyrolyzed at 300 and $550^{\circ}C$, and then amended with soil at a rate of 5%. All the earthworms survived, but lost weight compared to control soil after 28 day incubation period. Moreover, the BC-amended soils did not significantly affect the cocoon numbers of earthworms. Slightly higher concentrations of 8-OHdG and CAT were observed in earthworms present in BC-treated soil than those in control soil. Furthermore, the 8-OHdG concentrations in the soil amended with BC produced at $550^{\circ}C$ were greater than those at $300^{\circ}C$, and it slightly decreased as the incubation time increased. CONCLUSION: These observations could be due to higher contents of toxic metal(loid)s and also higher pH in BCs pyrolyzed at $550^{\circ}C$ than $300^{\circ}C$. While BC is efficiently being used in agricultural fields, this study suggests that it is required to assess the unintended negative impacts of BC on soil ecosystems.

• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.267-271
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• 1995

To improve regeneration efficiency of Brassica campestris ssp. pekinensis (chinese cabbage) in vitro, the effect of ehtylene inhibitors [AgNO$_3$ and silver thiosulfate (STS)] and optimal age of explantse were investigated. On the effect of ethylene inhibitors either 100 $\mu$M of AgNO$_3$ or 5 $\mu$M of STS enhanced shoot regeneration from cotyledons when it was added in basal shoot induction media(MS salts, B5 vitamine, sucrose 2%, BA 2.0mg/L, NAA 1.0mg/L). But at higher concentrations, AgNO$_3$ induced abnormal shoots, and STS greatly reduced regeneration frequency. On the other hand, the maximum regeneration rate was obtained from the cotyledons taken from 3-day old seedlings. However there was no distinctive effect among the containers used for cultivation. The most optimal condition of root induction was a minimal Murashige and Skoog media containing 0.1 mg/L NAA. In order to induce bolting and flowering from in vitro regenerated chinese cabbage, the plant were healed at 4$^{\circ}C$ for weeks in a cold chamber. When they were planted in pots, the plane produced phenotipically normal flowers and seeds. The overall results suggest that ethylene inhibitors promote regeneration of shoot from cotyledons of chinese cabbage without alleviating fertility.