• Journal of Aquaculture
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• v.4 no.2
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• pp.97-110
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• 1991

This study was undertaken to understand the seasonal changes of hormone levels such as luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol-$17{\beta}$, serum components such as albumin, total protein and triglycerides, and GSI of rainbow trout (Onco-rhynchus mykiss) under the normal-light circumstances. LH levels were the highest in November whereas FSH levels were decreased progressively from October to February. Serum GTH, such as LH and FSH, levels were low immediately after egg-stripping and were significantly increased in the summer in association with the initiation of vitellogenesis. Serum albumin, total protein, and triglycerides were significantly increased in August in association with initiation of vitellogenesis and were peak in November prior to egg-stripping. Oocyte growth, measured by oocyte diameter and GSI, was significantly increased in August and showed the highest value in January. Correlation coefficients of serum LH with FSH and estradiol-$17{\beta}$ were +0.844 and +0.947, respectively. Correlation coefficients of estradiol-$17{\beta}$ with albumin and total protein were +0.634 and +0.859, respectively. Correlation coefficients of serum estradiol-$17{\beta}$ with triglycerides and GSI were +0.673 and +0.694, respectively. Probably by positive feedback mechanism, LH, FSH and estradiol-$17{\beta}$ appeared to stimulate to liver to secrete albumin, total protein and triglycerides for vitellosenesis.

• Clinical and Experimental Pediatrics
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• v.46 no.1
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• pp.42-50
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• 2003

Purpose : The acute respiratory distress syndrome(ARDS), an acute form of severe alveolar-capillary injury evolving after a direct or indirect lung insult is thought to be a common cause of respiratory failure though not many clinical studies on the subject have been made yet. Methods : Between January 1992 and December 2001, we conducted a retrospective study on 33 children who fulfilled the definition of the ARDS recommended by the American-European Consensus Conference in 1994. Results : A total of 33 patients(20 boys and 13 girls) were selected. Their age ranged from 4 months to 12 years with seven children younger than 1 year. The overall mortality rate was 78.8% and no significant difference was noted based on age or sex. Concerning seasonal variation, incidence of the ARDS increased in spring, especially in May(21.2%). Pneumonia(66.7%) was found to be the most common risk factor of the ARDS followed by sepsis(24.2%) and aspiration(3.0%). In immune compromised children(six cases), including a recipient of bone marrow transplantation, the mortality rate was 100%. Compared with children with multiple organ failure recording a 83.3% mortality rate, those with isolated respiratory failure, showed a lower mortality rate of 33.3%, although stastistically insignificant. Between survivor and non-survivor groups, significant differences were shown in hematocrit, $PaO_2$, $PaCO_2$, PEEP, and $PaO_2/FiO_2$ on the seventh day after the onset of the ARDS. Conclusion : According to our study, respiratory failure proved to have a great effect on mortality rate in the ARDS. More aggressive intervention and further studies on this subject should be done to improve the survival rate.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.69-83
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• 2006

This experiment was conducted to investigate effects of application of diluted and undiluted cattle slurry with water on seasonal and annual dry matter yields and feed values of tall fescue in the uncultivated rice paddy and it was compared with chemical fertilizer. Annual dry matter yields for diluted (average 6.43 ton DM/ha) and undiluted (average 6.56 ton DM/ha) cattle slurry were significantly higher (p<0.05) than those of no fertilizer (3.82 ton DM/ha). This trend was much more conspicuous in treatments applied in spring. In chemical fertilizer treatments, fertilizers with P and K (6.12 ton DM/ha), and P, K and N (10.13 ton DM/ha) had significantly (p<0.05) higher dry matter yields compared with no fertilizer. However, annual dry matter yields for treatments of P and K mixture tended to be lower than those of cattle slurry applications. The efficiency of DM production for inorganic nitrogen in chemical fertilizers annually averaged 26.7kg DM/kg N. In terms of cutting frequencies, it was highest in 2nd growth followed by 1st and 3rd growth. On the other hand, efficiencies of annual DM production of nitrogen for diluted and undiluted cattle slurry were 18.3 and 17.4 kg DM/kg N, respectively, especially, highest in 2nd growth. While, efficiencies of DM production for cattle slurry versus for inorganic nitrogen were 68.5 (undiluted) and 65.2% (diluted), respectively. For annual crude protein contents of tall fescue, no fertilization (11.5%) was significantly higher than chemical fertilizer, but that was lower than cattle slurry ($12.4{\sim}12.6%$) diluted with water. on the contrary, no fertilizers had significantly lower NDF (64.1%) and ADF (37.2%) contents than those of any other treatments, but their RFV (87.0) was significantly higher (p<0.05) than other treatments. The application of cattle slurry and their dilution significantly increased yields of crude protein and total digestible nutrients compared with no and/or P and K fertilizers (p<0.05). This trend was more conspicuous in cattle slurry applied in the early spring.

• Journal of Embryo Transfer
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• v.28 no.1
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• pp.19-24
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• 2013

This study assesses of efficiency of oocyte recovery and in vitro development for during the non breeding season in goat. Thirty-four matured goats, maintained in a pen under natural day length and fed hay ad libitum, were pretreated with progestagen implanted CIDR for 10 days. Superovulation treatment of the goats received twice daily intramuscular injections of a total of 70 mg FSH for 3 days from Day 8 of CIDR. All the gonadotropin treated goats were injected with 10 mg $PGF_2{\alpha}$ on Day 8 and 400~600 IU hCG in the afternoon on Day 10. Oocytes were recovered by follicle aspiration or oviduct flushing at 35 to 40 h after hCG injection through mid-ventral incision. The in vivo matured oocytes were activated by ionomycin (5 min) and 6-DMAP (3.5~4 h). The activated oocytes were cultured in mSOF medium containing 0.8% BSA at $38.5^{\circ}C$ in an atmosphere of 5% $CO_2$, 5% $O_2$, 90% $N_2$ for 7~8 days. There was no significant difference in the mean number of CL and in vivo matured and follicular oocytes recovered. But, quality of I+II grade follicular oocytes was lower (p<0.05) in the prepubertal goat (25.0%) than the adults (52.4%). The same results were also observed in the cleavage and blastocyst rate of activated oocytes. The clavage and blastocyst rate from prepubertal derived oocytes were lower (p<0.05) in the prepubertal goat (54.5%, 23.3%) than the adult goat (86.8%, 46.6%). Considering overall these results, we suggest that maturation of donor goats is a major factor affecting recovered oocytes quality and in vitro development of activated goat oocytes. There was no significant difference in oocyte quality between seasonal treatments.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.13-19
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• 2000

Seasonal variations of dominant algae species and the effects of these algae on coagulation and filteration of water treatment were investigated at Chilseo water treatment plant in downstream of Nakdong river from January in 1995 to Desember of 1998. The water quality of Nakdong river was found to be a hyper eutrophic state during the investigation periods. In the measurement, Chlorophyll-a contents ranged $20.7{\sim}180.9{\mu}g/l$ and total nitrogen contents(T-N) and total phosphorus contents(T-P) exceeded more than 3.4mg/l and 0.1mg/l, respectively. The changes in dominant algae species was in the order of Stepanodiscus sp., Asterionella sp., Melosira sp., Microcystis sp. and Synedra sp. from spring to winter. Microcystis sp. especially, was blooming during summer and Synedra sp. and Stepanodiscus sp. during winter. Although most diatomous algae appeared in the water treatment process caused filter clogging and reduced efficiency of coagulation and sedimentation, Synedra sp. and Stepanodiscus sp were revealed as the main trouble algae. Malfunction of water treatment process caused by Synedra sp. and Stepanodiscus sp. started at the algae concentrations of 800cells/ml and 1,820cells/ml, respectively. When chlorophyll-a content was $18.9{\mu}g/l$, the optimum amounts of coagulant were found to be 40mg/l of Alum and 16mg/l of PACS. Under condition of chlorophyll-a content of $154.1{\mu}g/l$, addition of Alum at the level of 75mg/l and PACS at the level of 35mg/l showed the lowest turibidity. The result indicates that increased amounts of the coagulants should be added for a better water treatment as chlorophyll-a contents increased. Addition of Alum at the amount of 60mg/l and 30mg/l of PACS removed Stepanodiscus sp. algae at the rate of 85% and 83%, respectively. In case of Synedra sp., 50mg/l of Alum and 25mg/l of PACS showed removal rates of 79% and 81%, respectively. Synedra sp. algae at the standing crops of 1,500cells/ml started filter clogging and a filtering process was completely inhibited after 8 hours. At this situation the filter clogging by Synedra sp. algae occurred at the depth of 5cm from the top anthracite layer. On the other, other algae did filter clogging at the depth of 10cm.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.35-41
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• 2008

Nutrient Enrichment Bioassays (NEBs) were conducted in the laboratory during June $22{\sim}28$, 2006 in order to determine primary limiting factor on the phytoplankton growth. For the NEBs, the water was sampled using a 10L polyethylene-lined container and dispensed into 2.5L container in the laboratory. The algal growths response in the control (C) and three treatments of phosphorus (P), 2-fold phosphorus (2P), and nitrate nitrogen $(NO_3-N)$ were monitored during 7 days. In the cubitainers which were spiked as P (T1) and 2P (T2) Chl-${\alpha}$ concentrations were decreased during the test period and the final concentrations was low than initial values. However, Chl-${\alpha}$ in the cubitainers which were spiked as $NO_3$(T3) and $P+NO_3$(T4) showed significant increases compared to the initial values, indicating that in the short-term experiments, nitrogen seemed to be a primary limiting nutrient during the periods of NEBs experiment. Long-term ambient nutrient data of TP and TN, and TN:TP mass ratios, however, showed a potential phosphorus limitation on phytoplankton growth and previous other researchers showed a variations of limiting nutrients by nitrogen or phosphorus depending on the seasons sampled and locations. In this study nitrogen as primary limiting nutrient in the NEBs seem to be an seasonal effect rather than the consistent nitrogen limitation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.179-184
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• 1986

The pot trial was carried out to investigate the influence of soil temperature on the growth and dry matter accumulation in sorghum cv. Pioneer 931 and corn cv. Suweon 19 during their growing season in 1985. Soil temperature maintained with low ($22.3^{\circ}C$), natural($25.9^{\circ}C$) and high temperature($30.5^{\circ}C$) over 24 hour. The results are summarized as follows; 1. Growth of sorghum plants was associated with increasing of soil temperature, while that of corn was reduced under high temperature($30.5^{\circ}C$). The highest plant height of corn was found at natural temperature($25.9^{\circ}C$). Sorghum had higher growth rate than corn plants in all temperature levels. 2. Assimirable leaf areas of the plants were greately increased under high temperature both in sorghum and corn. Sorghum plants maintained almost same levels of leaf area during maturity stage, but those of corn were markedly decreased after mild stage. 3. The highest rates of photosynthesis were found at nature' soil temperature ($25.9^{\circ}C$) both in sorghum($1.619mg/s/m^2$) and corn plants($1.084mg/s/m^2$). Under high temperature($30.5^{\circ}C$) the photosynthesis rates of the plants were decreased to about 1.553 mg and 0.404 mg for sorghum and corn, respectively. Low temperature ($22.3^{\circ}C$) produced only a value of 0.775 mg for sorghum and 0.048 mg for corn. 4. Seasonal dry matter accumulation of sorghum increased in the order of high>natural>low soil temperature, but that of corn increased in the order of natural>high>low soil temperature, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.7-14
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• 2020

This study was conducted to find out the effects of seed mixture using new domestic grass varieties orchardgrass 'Onnuri' and tall fescue 'Greenmaster' on botanical composition and dry matter productivity from 2015 to 2018 in oversown hilly pasture, the central northern area of Korea. This experiment was consisted of 4 mixed grasses (Treatment 1 : tall fescue oriented mixture with imported varieties; Treatment 2 : orchardgrass oriented mixture with imported varieties; Treatment 3 : orchardgrass oriented mixture with domestic varieties, Treatment 4 : tall fescue oriented mixture with domestic varieties). Evaluation of seasonal changes in botanical composition of pasture showed that orchardgrass was the highest in all treatments, ranging from 46 to 89% and Kentucky bluegrass was the second highest in all treatments. Treatment 3 (7,633 kg ha^-1) and Treatment 4 (7,570 kg ha^-1), mixed grasses using domestic varieties, were showed the highest dry matter yield than Treatment 1(6,950 kg ha^-1) and Treatment 2 (6,934 kg ha^-1), which were mixed grasses using introduced varieties. Therefore, these results showed that the orchard grass oriented grasses mixture with domestic varieties was good for grassland vegetation and productivity in oversown hilly pasture, the central northern area of Korea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.149-160
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• 2007

KoFlux Gwangneung Supersite comprises complex topography and diverse vegetation types (and structures), which necessitate complementary multi-disciplinary measurements to understand energy and matter exchange. Here, we report the results of this ongoing research with special focuses on carbon/water budgets in Gwangneung forest, implications of inter-dependency between water and carbon cycles, and the importance of hydrology in carbon cycling under monsoon climate. Comprehensive biometric and chamber measurements indicated the mean annual net ecosystem productivity (NEP) of this forest to be ${\sim}2.6\;t\;C\;ha^{-1}y^{-1}$. In conjunction with the tower flux measurement, the preliminary carbon budget suggests the Gwangneung forest to be an important sink for atmospheric $CO_2$. The catchment scale water budget indicated that $30\sim40%$ of annual precipitation was apportioned to evapotranspiration (ET). The growing season average of the water use efficiency (WUE), determined from leaf carbon isotope ratios of representative tree species, was about $12{\mu}mol\;CO_2/mmol\;H_2O$ with noticeable seasonal variations. Such information on ET and WUE can be used to constrain the catchment scale carbon uptake. Inter-annual variations in tree ring growth and soil respiration rates correlated with the magnitude and the pattern of precipitation during the growing season, which requires further investigation of the effect of a monsoon climate on the catchment carbon cycle. Additionally, we examine whether structural and functional units exist in this catchment by characterizing the spatial heterogeneity of the study site, which will provide the linkage between different spatial and temporal scale measurements.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.887-898
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• 2007

A physically based semi-distributed model, SWAT was applied to the Chungju Dam upstream watershed in order to investigate the spatial and temporal characteristics of watershed sediment yields. For this, general features of the SWAT and sediment simulation algorithm within the model were described briefly, and watershed sediment modeling system was constructed after calibration and validation of parameters related to the runoff and sediment. With this modeling system, temporal and spatial variation of soil loss and sediment yields according to watershed scales, land uses, and reaches was analyzed. Sediment yield rates with drainage areas resulted in $0.5{\sim}0.6ton/ha/yr$ excluding some upstream sub-watersheds and showed around 0.51 ton/ha/yr above the areas of $1,000km^2$. Annual average soil loss according to land use represented the higher values in upland areas, but relatively lower in paddy and forest areas which were similar to the previous results from other researchers. Among the upstream reaches, Pyeongchanggang and Jucheongang showed higher sediment yields which was thought to be caused by larger area and higher fraction of upland than other upstream sub-areas. Monthly sediment yields at the main outlet showed same trend with seasonal rainfall distribution, that is, approximately 62% of annual yield was generated during July to August and the amount was about 208 ton/yr. From the results, we could obtain the uniform value of sediment yield rate and could roughly evaluate the effect of soil loss with land uses, and also could analyze the temporal and spatial characteristics of sediment yields from each reach and monthly variation for the Chungju Dam upstream watershed.