• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.406-418
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• 2021

This study was conducted to evaluate optimal storage techniques for bare root plants and container seedlings of Quercus variabilis and Zelkova serrata in order to maintain high quality of seedlings until planting. Refrigerated storage treatments were given at two temperatures (-2℃ [freezing] and 2℃ [cooling]) for nine different durations (0, 15, 30, 60, 120, 180, 240, 300, and 360 days after storage). We analyzed total nonstructural carbohydrate (TNC) content and measured shoot moisture content (SMC) during the storage stage and survival rate (SR) and dry weight during the planting stage of seedlings. The TNC content and SMC of the seedlings of the two species decreased with an increase in storage duration. The TNC content of seedlings rapidly decreased after 180~240 days of storage. The TNC reduction rate in the freezing treatment was lower than that in the cooling treatment. Also, with an increase in the storage duration of the two species, the SMC reduction rate in the cooling treatment increased in comparison with that in the freezing treatment. In both the species, the SR after planting decreased rapidly after 60 days of cooling storage and 180 days of freezing storage, respectively. The SR after planting was less than 60% when the TNC content for both the species dropped below 20 mg g^-1. In addition, the SR was lower than 80% when SMC measured before storage decreased by approximately 30% and 20% for Q. variabilis and Z. serrata, respectively. Our results suggest that cooling (1~2℃) storage is recommended for a short-term period (2 months or less), whereas freezing (-2~-4℃) storage is suitable for longer periods (2~6 months). These optimal storage techniques, allied with seedling harvesting and handling systems, will improve the quality of seedling production in nursery stages and increase seedling growth performances in plantations.

• The Korean Journal of Malacology
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• v.30 no.2
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• pp.107-116
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• 2014

Gonadal development and maturation mechanism were studied on the freshwater marsh clam Corbicula papyracea (Heude), which is the endangered species in Korea. The specimens were collected in the rearing ponds and waterway of NFRDI in Gapyeong-gun, Gyeonggi-do from January to December 2004, and then investigated by condition factor, relative growth, gonadal development phases and gonad histological characters based on 30-50 individuals every month. Comparing with the freshwater marsh clam, C. papyracea is small, light olive brown shell and violet interior. The hermaphrodite individuals of C. papyracea take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The average water temperature of inhabit area was in range of $1.8-27.0^{\circ}C$ and usually took great effects on the gonad maturation of C. papyracea. The condition factor ranged from 0.14 to 0.21 throughout the year, which was the lowest during winter season (December-February), and gradually increased to the highest value of 0.21 in May. The ratio of meat weight to total weight was 25.9-38.7%, indicating the similar trend with condition factor. The highest values of condition factor and the ratio of meat weight appeared 1-2 months later than gonadosomatic index reached the peak value, it was probably because that the ovoviviparous eggs would spend a long period before hatching from the foster-sack in the gills. To synthesize the characters of meat weight, condition factor and gonad development by histological study, reproductive cycle of C. papyracea could be divided into five successive stages: multiplicative stage (December to February), growing stage (February to May), mature stage (June to August), spawning stage (August to November), recovery stage (November to December). The smallest shell length of matured C. papyracea was 12.6 mm, and individuals, larger than 16 mm, was formed the nursery in the gills.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.25 no.1
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• pp.1-5
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• 2014

In order to resolve the decline in population due to low birthrates, the South Korean government is expanding its free child care policies with an increased budget. In anticipating the effects and problems of our system, it will be worthy of attention to refer to the child care systems of other countries. In this paper, we reviewed the past and present policies and the current situation of the child care system in North Korea. North Korea started its free child care system earlier than that of South Korea, for the purpose of utilizing the women's labor force and rearing children to be revolutionary men of Juche type (Kimilsungism), in order to construct a communistic society. 'Child Care Education Law', which is the legal foundation of the child care system, regulates institutions for nursery schools and kindergarten and informs people that the country is responsible for support of child care. Despite their interest and progress in both quantity and quality in the child care system until the 1980s, the free child care system was partially disrupted, and discrepancies between ideology and actual situation were revealed due to economic difficulties from the 1990s. Because people's survival and physical health have been threatened, it is barely possible to find any study investigating the effect of institutional child care from early childhood and the instillation of unique ideology by group education from the preschool period on mental health.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.1-10
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• 1984

Two fast-growing clones 65-29-19 and 66-6-8 and two less fast-growing clones 66-14-29 and 66-14-99 were compared at intensively cultured plots to identify what morphological characters are related to fast growth and high biomass yield of Populus alba ${\times}$ Populus glandulosa $F_1$. The plantations were established in the spring of 1982 and 1983 at the Seoul National University nursery in Suweon. Differences in dry matter production were found among two-year-old clones but not, among one-year-old clones. Highly significant correlations were found between total leaf area per tree and total dry weight per tree and between total branch length per tree and total dry weight per tree for two-year-old clones. This relation was more obvious during the late growing season. Morphological characters desirable for producing high biomass identified in fast-growing clones were as follows; high shoot-root ratio, high leaf surface area per tree, long leaf retention period, and many small leaves and compact crown architecture in the upper portion of true crown.

• Research in Plant Disease
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• v.16 no.3
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• pp.279-284
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• 2010

Clubroot caused by Plasmodiophora brassicae is a widespread disease that causes serious problems in many brassica growing areas. To establish more simple and reliable clubroot screening method of Chinese cabbage to P. brassicae using soil-drenching inoculation, the development of clubroot on Chinese cabbage according to several conditions such as soil type, inoculum concentration of P. brassicae GN-1 (race 9), plant growth stage and incubation period was studied. In a commercial horticulture nursery media soil (CNS), disease severity of the seedling according to inoculum concentration increased in a dose-dependent manner, but did not in mixture of CNS and upland soil (1:1, v/v). To facilitate and acquire precise result of resistance screening of Chinese cabbage to clubroot, 10-day-old seedlings should be inoculated by drenching the spore suspension of P. brassicae to give inoculum density of $4.0{\times}10^8$ spores/pot. To develop the disease, the inoculated seedlings were incubated in a growth chamber at $20^{\circ}C$ for 3 days, and then cultivated in a greenhouse ($25{\pm}5^{\circ}C$) for five weeks. Under the optimum conditions, 25 clubroot-resistant (CR) and 3 clubroot-susceptible (CS) cultivars were tested for resistance to P. brassicae. All CR cultivars showed very clear resistance response, on the other hand all CS cultivars severly infected with the pathogen. The results suggest that this method is efficient screening method of Chinese cabbage for resistance to clubroot disease.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.11
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• pp.1496-1502
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• 2010

Two experiments were conducted to evaluate the effects of diet complexity and fermented soy protein on growth performance and amino acid digestibility. In Exp. 1, a total of 120 crossbred weanling pigs ($5.68{\pm}0.80\;kg$ BW) were randomly allocated into 4 treatments. Each treatment had 6 replicate pens comprising 5 pigs in each replicate. Experimental diets consisted of simple (soybean meal as protein source) and complex (soybean meal, rice protein concentrate, potato protein concentrate and fish meal as protein sources) diets; each diet contained 0 or 5% fermented soy protein (FSP), respectively. Dietary treatments included: i) simple diet; ii) simple diet with 5% FSP; iii) complex diet; iv) complex diet with 5% FSP. Pigs were provided each experimental diet for 20 d (phase 1) and then fed the same common diet for 10 d (phase 2). During days 0-10, pigs fed FSP diets had greater ADG than those fed non-FSP diets (p<0.05). G/F in FSP treatments was significantly higher than that in non-FSP treatments (p<0.05) from days 0 to 10. Throughout the overall period, G/F was greater in FSP treatments compared with non-FSP treatments (p<0.05). On d 10, N digestibility was higher in pigs fed FSP diets than in those fed non-FSP diets (p<0.05). Diet complexity did not affect growth performance and nutrient digestibility (p>0.05) in this experiment. In Exp 2, 12 ileal-cannulated, weanling barrows were housed in individual metabolism crates and randomly assigned to 1 of 4 treatments (same as Exp. 1) by using a $4{\times}4$ Latin square design. Among the essential amino acids, apparent ileal digestibility (AID) of Met and Val were increased in pigs fed FSP diets compared with those fed non-FSP diets (p<0.05). AID of Met, Phe and total essential amino acids were higher in pigs fed complex diets than in those fed simple diets (p<0.05). Among the non-essential amino acids, AID of Ala in FSP treatments was greater than that in non-FSP treatments (p<0.05). In addition, Asp, Cys, Glu, Pro, Ser and total non-essential amino acid digestibilities in pigs fed complex diets were higher compared with those fed simple diets (p<0.05). Interaction was observed in AID of Met, Asp and Pro. In conclusion, these results indicated that feeding of 5% FSP to nursery pigs improved feed efficiency and AID of amino acids, and diet complexity did not maximize the growth performance of pigs in the subsequent phase.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.112-117
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• 2002

This study was conducted to induce the optimal composting conditions of pig manure mixed with sawdust and dried paper-mill sludge in the composting for production of high quality compost. Pig manure contains high water content and How C/N ratio because of comparatively high nitrogen content than sawdust and dried paper-mill sludge. Therefore the addition of dried paper-mill sludge and sawdust to the raw materials helps controlling the C/N and the water content of compost pile. The composting system used in the experiment was agitated static bed system. The physical properties of the mixed raw materials was not good at the working conditions in the early stage of composting. The temperature of compost heap reaches at $60^{\circ}C$within 5 day after starting composting in P-2 treatment mixed with pig manure and sawdust(56.6 : 43.4). Then the water content of P-2 was 58%. The pH in all treatments were slowly decreased as the composting was proceeded. Although the changes of T-C and T-N were not extended because of the short composting experiment period. Reduction rates of T-C in treatments were 5-12% without special difference. By considering the efficiency of composting in each of five treatments with pig manure the optimal water contents was about 57% level. Mixing a sawdust as a bulking agent was more positive than dried paper-mill sludge from a viewpoint of compost quality.

• Women's Health Nursing
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• v.2 no.2
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• pp.182-201
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• 1996

The purpose of this study is to examine a married nurse's experience of child rearing through being applied to phenomenological research method. By exchanging their experiences, helping and understanding one another, married nurses can work with delight considering their own present job as their lifelong job. In addition this study can help single nurses overcome the female crises such as marriage, childbirth, and child rearing they will experience in the future. The subjects of this research was 26 married nurses who work for a university hospital in affiliation in Seoul and have children. The period of materials collection was from Feb. 1st to Mar. 3, 1995. The method of materials collection was primarily to write down a questionary with openhearted contents. In collecting it, the respondents were allowed to say at their pleasure through further interview. The materials were analyzed by Giorgi's phenomenological analysis method. The findings of this study are as follows ; 1) The responses of married nurses' experience of child rearing-[pleasure] [family solidarity] [maternal-infant attachment] [understanding] [toilsome]-were induced. That is, at once affirmative experience and hard experience coexisted. 2) The method of married nurses' child rearing-[rearing politely] [raising understanding] [having the sense of family community] [rearing with praying the heart] [careless]-were induced. 3) The support system of married nurses' child rearing-[having help family] [having help from others]-were induced. According to the above findings, the married nursed showed affirmative responses about their experience of child rearing, but at the same time they expressed painful when stayed apart from their children on account of their job or when their children were sick. In the method of child rearing, they tried to grow their children polite because there was much time for them to stay apart from their children. And they tried to give a better explanation in order that their children can have an independence spirit. They tended to compensate through frequent physical touch with their children. As the support system of married nurses' child rearing, they asked their parents or their parents-in-law to take care of their children, hired a nursery governess in their houses, or used a children's home, if they can't afford to. That is, the only one who has a firm sense of her profession, tries to inspire her accomplishment, and is receiving her husband' love and understanding is considered to perform two things simultaneously with harmony, having an recognition of lifelong job. Suggestions 1. The method to solve mental troubles on child rearing should be groped. 2. Their economical burden should be reduced by establishing children's home in their working places, and the increase of maternal-infant interaction should be contrived. 3. The chance of education should be offered in order that married nurses themselves might inspire self-conceit and professionalism on clinical nursing. 4. The familiar mood should be created through planning the programs to be accompanied with children as an annual event in hospital. 5. The part-time nurse system should be suggested to utilize. 6. The system of circulation working should be converted into the system of fixing working according to the characteristic of each department. 7. Programs for special activities such as learning foreign languages and computer should be supported positively.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.252-261
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• 2008

Two experiments were conducted to compare the effects of feeding organic acids and antibiotic growth promoters in weaned pigs. In Exp. 1, 96 nursery pigs (Large White$\times$Landrace; initial weight $7.80{\pm}0.07kg$) were randomly allotted into one of four dietary treatments. Pigs in treatment 1 were fed a complex starter diet. Treatments 2 to 4 were the same as treatment 1 but supplemented with antibiotics (200 ppm chlortetracycline plus 60 ppm Lincospectin), 0.5% potassium diformate or 0.5% dry organic acid blend ACTIVATE Starter DA (ASD). During the 4-week post-weaning period, pigs fed ASD or antibiotics had better gain (p = 0.03) and feed efficiency (p = 0.04) than pigs fed the control diet. On d 14 post-weaning, pigs fed the control diet had the lowest fecal lactobacilli count among all dietary treatments (p = 0.02), whereas pigs fed ASD or antibiotics had a trend for lower fecal E. coli count compared to the control pigs (p = 0.08). Serum insulin-like growth factor-1 (IGF-1) of pigs fed ASD did not differ from pigs fed the control diet (p>0.05) at d 14 after weaning. In Exp. 2, 24 weaned pigs (Large White$\times$Long White; initial weight $5.94{\pm}0.33kg$) were allotted into four groups and housed individually. Pigs were fed a control diet or diets supplemented with antibiotics (100 ppm colistin sulfate, 50 ppm Kitasamycin plus 60 ppm Olaquindox), 0.5% or 1% ASD. All pigs were orally challenged with E. coli $K88^+$ on d 5. During d 5 to 14 after challenge, pigs fed antibiotics, 0.5% or 1% ASD had better gain (p = 0.01) and feed efficiency (p = 0.03) than pigs fed the control diet. On d 14, compared to the control pigs, pigs fed 0.5% ASD had higher lactobacilli in the duodenum and pigs fed 1% ASD and antibiotics had a trend for higher lactobacilli in the ileum (p = 0.08). Pigs fed antibiotics, 0.5% or 1% ASD diets tended to have decreased ileal E. coli count compared to those fed the control diet (p = 0.08). Serum interleukin-6 and cortisol and digesta pH values were not affected by treatment or time. These results indicate that feeding ASD can improve the growth performance of weaning pigs, mainly via modulating intestinal microflora populations without affecting gastrointestinal pH or immune indices.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.1
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• pp.31-44
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• 2020

Accelerators that invest in early startups, as well as nursery and overall management, have recently emerged as "key players" in the startup ecosystem. This can be proved by the case where the number of domestic accelerators registered in the Korean Ministry of SMEs and Startups has recently reached 208. Accelerators provide the necessary education for early-stage companies, including guidance for a certain period of time, and support startups in ways such as demo days to attract subsequent investment after the seed investment. There is not much research in academia about what factors impact on these accelerators when making investment decisions at the time of seed investment. In this study, we checked the meaning and function of the accelerator and tried to analyze what factors affect on accelerators when making a decision to invest in startups. The research method is based on a literature survey of previous studies on investment decision-making factors of venture capital and angel investors, and a lens model and judgment analysis method through empirical research targeting 43 accelerator investment decision-makers. Empirical analysis shows that accelerators have three of the key factors to consider when choosing the first startup to invest and educate; entrepreneurs' entrepreneurial traits, their product and service expertise and a potential return on success. This will provide an opportunity for early startups to gain strategic access to accelerators when they need money or need a structured educational program. Also, the results obtained through this research will be a kind of guideline for startups to attract accelerators' investment. The significance of this study is that discriminatory evidence was presented on the accelerator determinants of investment, and it would be highly suggestive to startups and related public institutions.