• Clinical and Experimental Reproductive Medicine
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• v.18 no.1
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• pp.63-71
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• 1991

To establish the normal fertile range in the results of the sperm zona-free hamster ova penetration assay (SPA) in Korean male, SPA using the low temperature ($4^{\circ}C$) capacitation in TEST-yolk buffer (TYB) was performed in 67 fertile and 26 infertile men. Sperm parameters in routine semen analysis were also checked and compared with the results of SPA. Sperm concentration, motility and motility index (MI) were significantly higher in fertile group compared with infertile group: $96.0{\pm}46.6$ vs $43.6{\pm}31.9{\times}10^6/ml$, $65.5{\pm}14.8%$ vs $45.8{\pm}23.6%$ and $46.31{\pm}13.29$ vs 27.40{\pm}17.98$, respectively. In fertile group, the hamster ova penetration rate (PR) was $98.5{\pm}5.0%$ (80%-100%), and the penetration index (mean penetrations per ovum, PI) was $9.59{\pm}6.35$(3.1-29.0). All the fertile men showed PI>3.0. In infertile group, PR was $24.6{\pm}24.8%$ (0%-70%), and PI was $0.40{\pm}0.42$ (0-1.3). Both PR and PI were significantly lower in infertile group. There was a significant correlation beween PI and sperm motility or MI, respectively, in fertile group whereas there was no correlation in infertile group. These data suggest that SPA using the low temperature capacitation in TYB can be a valuable diagnostic tool for the assessment of male fertility in vitro and provide an important supplement to the traditional tests of sperm quality.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.280-287
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• 1997

This study was carried out to investigate agricultural status and soil fertility of Bonghwang-cheon watershed area which is located at Chodong-myeon, Milyang-si. The acreage of arable land was about 1,209ha, and the population was 3,706 people. Out of total arable land, paddy was 64.4%, upland 19.6% and orchard 16.0%. Chicken was the largest in the number of livestock and poultry, but pig seems to contribute most severly to water pollution. The geology in the lower stream was alluvium but andesite and derivated materials from it were occupied most upland areas. Tuff was scattered in the small area near by the alluvium of Nakdong river, and diorite and granodiorite were located at the low hill and mountains respectivately. The principal paddy soils in the area were Geumgog, Jisan and Imgog series etc of fine loamy on sloped valleys and fans. The Pyeongtaeg series, fine silty family of imperfectly drained on plain was irrigated by Chodong reservoir. The clayey Honam series on alluvium was distributed along the low hill while Gyuam series, coarse silty alluvial soil way close to Nakdong river. In chemical properties of soils, the vinyl house soils were higher in EC, and orchard soils in OM, $P_2O_5$, exchangeable canons than other soils.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.1-17
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• 1991

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.161-169
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• 2013

This study was carried out to examine characteristics of physical and chemical current status and problems of Salix spp. communities based on growth characteristics by tree age and height of the tree species in around Namgang Dam reservoir area. Tree density in 4 survey areas was 5,284 trees/ha, but all areas need to control high tree density. Tree crown area in 4 survey areas was 9,786.4 $m^2/ha$ and crown area of Salix spp. was the most dominant among tree species in watershed of the Jinyang lake. Mean soil depth in 4 survey areas was 65.5 cm higher in the sedimental deposit soil (78 cm) than in forest soil (12.5 cm) near the watershed. Soil bulk density was also higher in the sedimental deposit soil than in forest soil because of poor porosity in the sandy sediment. Soil pH was higher in sedimental deposit soil (A, B horizon:pH 6.7) than in forest soil (A horizon:pH 5.3; B horizon:pH 5.2) because of originated from non-point source polution and detergent of domestic sewage. The results suggest that growth of Salix spp. could be poor because of low fertility with low cation exchange capacity in sedimental deposit soil.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.76-82
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• 2019

BACKGROUND: For sustainable agriculture, there are various agricultural practices including low input. Over the last few decades high input of chemical fertilizer and compounds results in environmental pollution and deterioration of soil fertility. Soybean (Glycine max L.) is well known eco-friendly crop due to their symbionts. Soybean has a relationship with nitrogen fixation bacteria called rhizobia. In this research work, we investigated effects of soybean cultivation on soil microorganism activities. METHODS AND RESULTS: Experiments were conducted in pots and potato cultivation was used as reference. Soil chemical properties were analyzed considering soil nutrient over cropping period. For the soil microbial community analysis, dehydrogenase activity analysis (DHA) analyzed along with denaturing gradient gel electrophoresis. The results showed that higher soil organic matter in the soybean cultivation soil than in the potato cultivation soil. Available $P_2O_5$ concentration increased gradually in both pots but showed higher value in the potato cultivation soil. DHA value implying microbial activities showed higher value in the soybean cultivation soil over all cropping period. CONCLUSION: The cause of high microbial activity in the soybean cultivation soil was considered to the effects of some specific microorganisms related to soybean cultivation. Therefore, the availability of soybean cultivation for sustainable agriculture should be encouraged in terms of microorganism community activity in soil.

• Korean Journal of Psychosomatic Medicine
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• v.30 no.2
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• pp.99-111
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• 2022

Akey factor in evolution is reproduction, which is also a major concern in medicine. Evolutionists have proposed many theories and hypotheses to explain the low fertility rates of modern industrial societies, which are contrary to maximization of biological fitness. Given that childbirth is the most significant factor affecting reproductive fitness, it is likely that a variety of psychological modules related to childbirth behavior and intention evolved over time. Several evolutionary psychological modules have been proposed in relation to reproduction, including sexual desire, status-seeking, a need for nurturing, and the desire for children. Previously adaptive psychological modules may now be expressed maladaptively due to the discrepancy between the Environment of Evolutionary Adaptedness (EEA) and the environment of modern industrial society. Several evolutionary ecological factors influence childbirth intention in modern society, including individual personality factors, childhood life history experiences, and socioecological factors throughout reproductive life. By focusing on mental, social, and ecological factors, this review examines several hypothetical models relating to evolutionary psychological factors and childbirth decisions in modern industrial society, as well as a possible explanation for the low birth rate.

• Korea Science and Art Forum
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• v.31
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• pp.355-365
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• 2017

The future population of Korea is expected to reach the second highest level in the world by 2060 for the elderly. It is because of the rapid development of low fertility and medical technology. The burden of society for the elderly is expected to increase steadily. The elderly person firstly appears functional disorder. They have low ability in memory and in cognitive will be. Their activities are therefore limited. And economic production capacity is sharply reduced. Self-sufficiency is a difficult situation. They need help in economic and social aspects. Products for them need research and development. The elderly have a Mild Cognitive Impairment(MCI) stage with poor cognitive abilities. It is effective to combine pharmacological and non-pharmacological treatment methods for people with mild cognitive impairment. The effects of non-pharmacological treatments on music have been proven. This paper is a study on the appearance from the viewpoint of design in the development of ancillary instruments using music therapy techniques with Digital Convergence. For this study, we investigated the preference for external appearance of mild cognitive impairment. Two times surveys were conducted. As a result, the design of home care product for the hard cognitive impaired was different from that of a conventional game machine or set top box. It should be designed according to the user's special circumstances. They are memory and cognitive abilities. Products that meet physical and mental changes must be developed.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.4
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• pp.235-244
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• 1976

Following results are obtained by re-evaluating N. P. K. and soil improvement trials conducted from 1964 to 1969 in valley paddy soils in rolling lands (Jisan-series, imperfectly drained and Yongji-series, moderately well drained). 1. Average grain yield of rice in no fertilizer plots and the highest yield plots for Yongji-series (31 experiments) were 319 and 507kg/10a respectively, and that of Jisan-series (15 experiments) were 396 and 567kg/10a respectively. The fertility difference between two series may have been a result of the cultivation history. Jisan-series is a mature soil which has a long cultivation history and Yongji-series is sub-mature soil 2. Soil chemical characteristics for Jisan-series are charaterized by 12.8meq/100g in CEC, 6.5meq/100g in exchangeable Ca, 3.9% in OM, and 64 ppm in available $P_2O_5$ For Yongji-series they were 10.4meq/100g in CEC, 4.7meq/100g in exchangeable Ca, 3.2% in OM and 103ppm in available $P_2O_5$. 3. Deep plowing and application of organic matter and lime are expected to be effective in increasing fertility level of soils of Yongji-series. The same will be effective in some soils of Jisan series where the fertility level is low. 4. Jisan-series shows high response to nitrogen, while Yongji series shows sharp decrease in rice yield at the high levels of nitrogen. Both series, however, showed high response to nitrogen only when the OM level was higher than 3%. 5. The optimum level of nitrogen was 8~9kg for Jisan-series, and 10~11kg/10a for Yongji-series. The yield increase per kg of applied nitrogen was 12kg for Jisan-series and 13kg for Yongji series. 6. The optimum level of phosphorus at the optimum level of nitrogen was 6kg/10a for Yongji-series and 3kg/10a for Jisan-series. The optimum level of phosphorus, however, was different depending upon the nitrogen level. It was assumed that Yongji-series required more fertilizer (available $P_2O_5$ was 110ppm) than Jisan-series (available $P_2O_5$ was 64ppm) because the availability of P was higher in Jisan-series than Yongji-series due to the severe reduction of Jisan-series. 7. The response of potassium was also depending upon the nitrogen level. In Yongji-series the potassium response at 8kg/10a nitrogen level decreased with increasing levels of potassium, but the higher level of introgen, potassium response was also higher. In Jisan-series potassium response was recognized at all nitrogen levels. The optimum level of potassium at the optimum level of nitrogen was 8kg/10a in both serieses. 8. The reasonable ratio of NPK fertilizer seems to be 1:0.6:0.6:for Yongji-series and 1:0.4:1 for Jisan-series as N:$P_2O_5$:K.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.134-142
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• 1991

Since IR8, the first high-yielding rice cultivar characterised by semidwarf and high-tillering, was released in 1966, rice yields during the last two decades have apparently reached a plateau and subsequent efforts to further improve yielding ability have not resulted in visible gains. At this point of time, a new ideotype of rice plant would be necessary to increase grain yield potential. This experiment was conducted to investigate the yield contribution of different tillers within a plant in relation to an ideo type of rice plant. A low-tillering, large panicled IR25588 was compared with a high-tillering, small panicled IR58. Based on spikelet number and grain weight per panicle, the top six panicles in both low- and high-tillering cultivarswere significantly bigger than those in the other panicles. The top six panicles were M, PI, P2, P3, P4 and S1P2 in both cultivars. Their tillers had 100% probability of occurring. The top six tillers were characterised by earlier initiation and heading, longer growth duration, greater leaf area. and heavier culm and total dry weight per tiller. The top six panicles, based on grain weight was mainly due to higher spikelet number per panicle with little differences in 1,000 grain weight and percent fertility. They had also a greater number of high -density grains. The top six panicles were significantly bigger than the rest of the panicles in both low- and high-tilliering types suggesting that a new rice ideotype having six or fewer potential tillers or panicles per paint with 200 to 250 spikelets per panicle (a low-tillering, paicle weight type) may help increase grain yield potential since they have been shown to be superior physio-morphologically to the rest of the tillers.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.25-35
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• 1981

Some physical and chemical properties of forest soils in Korea were analyzed for providing the reasonable management methods of forest lands, Among 375 soil series surveyed until 1979, 93 soil series of forest soils were classified and analyzed according to their characteristics. Firstly soil data were classified into 5 categories by weathered products and secondly were classified and analyzed by parent rocks. The results are as follows: 1) In forest soils characterized by weathered products volcanic ash soils were proved to be the most fertile and alluvial soils were turned out to be the most infertile soils. Residual soils on mountain and hill were mostly on the average in all kinds of soil properties analyzed except total soil depth. 2) Igneous rocks developed rather infertile soils containing large amount of organic matter and available $P_2O_5$ with relatively deep soil depth and strong acidity. On the other hand sedimentary rocks produced rather shallow soils containing small amount of organic matter and available $P_2O_5$ but they were relatively fertile with weak acidity. 3) Among igneous rocks basalt and trachyte produced very fertile soils and granite and andesite produced slightly infertile soils. 4) Among sedimentary rocks limestone soils had high fertility neutral in acidity but low amount of available $P_2O_5$ 6) Alluvial sand produced generally very infertile soils with great soil depth comparing with the arable alluvial land with high fertility.