• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.267-275
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• 2000

In an effort to assess the reliability of satellite altimeter system, we conducted a comparative analysis of sea level data that were collected using the TOPEX/POSEIDON (T/P) altimeter and the 10 tide gauge (TG) stations in the satellite passing track. The analysis was made using data sets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Because of strong tidal activity in the study area, treatment of tidal errors is a very critical step in data processing. Hence in the computation of dynamic heights from the Tn data, we adapted the procedures of Park and Gamberoni (1995) to reduce errors associated with it. When these T/P data were treated, the alias periods of M$_2$, S$_2$, and K$_1$ constitutions were found at 62.1, 58.7, and 173 days. The compatibility of the T/P and TG data sets were examined at various filtering periods. The results indicate that the low-frequency signal of Tn data can be interpreted more safely with longer filtering periods (such as up to the maximum selected values of 200 days). When RMS errors for 200-day low-pass filter period was compared among the whole 10 tidal stations, the values spanned in the range of 2.8 to 6.7 cm. The results of correlation analysis at this filtering period also showed a strong agreement between the Tn and TG data sets over the whole stations investigated (e.g., P values consistently less than 0.0001). According to our analysis, we conclude that the analysis of surface sea level using satellite altimeter data can be made safely and reasonably long filtering periods such as 200 days.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.208-215
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• 2000

The estimated total material transports through the Cheju Strait using all data which investigated in 1997 and 1999 are as follows; A large amount of suspended sediments and dissovted inorganic nutrients are carried tothe South Sea through the Cheju Strait by a persistent eastward flow (Cheju Current) from the Y311ow Sea andthe East China Sea. The annual material Oanspous by the Cheju Current are as follows; 22.9${\times}$10$^6$ ton yr$^{-1}$(SS), 0.52${\times}$10$^{10}$ mol yr$^{-1}$ (NH$_4\;^+$), 6.05${\times}$10$^{10}$ mol yr$^{-1}$ (NO$_3\;^-$), 0.36${\times}$10$^{10}$ mol yr$^{-1}$ (PO$_4\;^{3-}$), 10.27${\times}$10$^{10}$ mol yr$^{-1}$ (Si(OH)$_4$). The annual suspended sediment flux per water transport in the Cheju Strait (44.48${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$) is about 1.7 larger than that in the Korean Strait (26.08${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$). The annual nitrate flux per water transport (11.60${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) is about 1.2 larger than that in the Korean Strait (9.72${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) and 2/3 of that by Kuroshio in the East China Sea (18.55${\times}$10$^{10}$ ton yr$^{-1}$ Sv$^{-1}$). It suggests that chemical rich Cheju Current will play a significant role in the biogeochemical processes in the South Sea where the huge land-based waste are introduced.

• Journal of Chest Surgery
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• v.37 no.6
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• pp.492-498
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• 2004

Background: In this study, we investigated the risk factors for the development or progression of aortic regurgitation(AR) in patients with type I ventricular septal defect (VSD) to determine the optimal surgical timing and strategy. Material and Method: Three-hundred and ten patients with type I VSD with or without AR were included. The mean of age was 73.7$\pm$114.7 (1-737) months. One hundred and eighty six patients (60%) had no AR, 83 (27%) had mild AR, 25 (8%) had moderate AR and 16 (5%) had severe AR. Aortic valve was repaired in 5 patients and replaced in 11 patients with closure of VSD in the first operation. Four patients required redo aortic valve repair and 11 patients required redo aortic valve replacement. Age at operation, association with aortic valve prolapse, Qp/Qs, systolic pulmonary arterial pressure, VSD size and systolic pulmonary artery to aortic pressure ratio(s[PAP/AP］) were included as risk factors analysis for the development of AR. The long-term result of aortic valve repair and aortic valve replacement were compared. Result: Older age at operation, association with aortic valve prolapse, high Qp/Qs, and s[PAP/AP] were identified as risk factors for the development of AR (p<0.05, Table 2). The older the patient at the time of operation, the higher the severity of preoperative AR and the incidence of postoperative AR (p<0.05, Table 1, Fig. 1). For the older patients at operation, aortic valve repair had higher occurrence of AR compared to those who had aortic valve replacement (p<0.05, Fig. 2). Conclusion: From the result of this study, we can concluded that early primary repair is recommended to decrease the progression of AR. Aortic valve repair is not always a satisfactory option to correct the aortic valve pathology, which may suggest that aortic valve replacement should be considered when indicated.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.209-216
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• 2000

This study was carried out to investigate the effects of breed, age of boar, season, parity and mating system on boar semen characteristics and fertilizing capacity. A total of 4181 sows and 199 boars of Durocs (D), Landraces (L), and Yorkshires (Y) were used for this experiment at Darby Artificicial Insemination Center from 1996 through 1999. Semen volume per ejaculate was largest in Landrace (266.8 $m\ell$), followed by Yorkshire, and was smallest in Duroc. Sperm motility did not show significant differences among the above breeds. Sperm concentration was lowest in Landrace (4.7$\times$10$^{9}$ sperm/$m\ell$) and was highest in Duroc (5.7$\times$10$^{9}$ sperm/$m\ell$). Semen volume per ejaculate according to the age of boars was largest at the age of 2 years, followed by the age of 4 and 3 years, and was smallest at the age of I year. Semen volume per ejaculate according to the season in boars was largest in winter (228.6 $m\ell$), followed by autumn and summer, and was smallest in spring. Sperm concentration was highest in spring (5.9$\times$10$^{9}$ sperm/$m\ell$), followed by summer and winter, and was lowest in autumn. The average litter weight at birth did not show any differences according to the mating type. But the number of pigs born alive per litter was largest (9.5 pigs) in the natural mating ＋ artificial insemination group, followed by the artificial insemination group (9.2 pigs), and was smallest (8.9 pigs) in the natural mating group (P＜0.01). The average litter weight at birth and number of pigs born alive per litter did not show any differences between the natural mating and artificial insemination. The L (♀)$\times$Y (♂) and L (♀)$\times$L (♂) matings show $\varepsilon$ d higher average litter weight at birth and number of pigs born alive per litter than the Y (♀) $\times$ Y (♂) and Y (♀) $\times$ L (♂) matings. The pigs in the 2~6th parities had higher average litter weight at birth and number of pigs born alive per litter than those in the 1 st and 7~9th parities.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.171-178
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• 2000

To improve the pig farm management and efficiency of swine industry by inducing the farrowing to day-time from night, In the first experiment, reproduction records of purebred and crossbred pigs were collected and analyzed to estimate the $\varepsilon$ ffec 잉 of factors affecting day and night farrowing. The general linear model was used to estimate the least square means of the factors affecting various reproductive characteristics. And also, chi-square tests were used to examine the independence of the reproductive traits and environmental factors using the SAS (1992). The comparisons between pure and crossbred pigs for total number born, percentage of number born alive, gestation length, time length for farrowing were determined. The results indicated that the gestation length of crossbred (115.11 d) was slightly longer than that of purebred (114.89 d, p＜0.05). For the seasonal effects on total number born, the largest was found in spring and no differences were found among summer, fall and winter. The average gestation length was 1 day longer in spring and winter than in summer and fall. The total number born and number born alive were smaller in first, second, and greater or equal to sixth parity than other parities. And also, the percentage of no. born alive was least in greater or equal to sixth parity. For the effect of mating methods, natural and artificial insemination, on total number born and number born alive, no differences between the two methods were found. However, the percentage of number born alive for natural mating was 98.06% and was higher than artificial insemination(93.75%). The time length for farrowing was I hour were found for the 6 hrs of farrowing time. In general situation of pig farms, day-time farrowing was 34.8% and night farrowing was 65.2%, indicating that night farrowing was almost double of the night farrowing.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.113-120
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• 2006

This study was conducted to select the optimum seed mixture for beef cattle (Hanwoo) grazing in middle mountain area at 450m from sea level during 2 years from October 1, 1999. Seed mixtures were composed of four different treatment according to main species such as orchardgrass (T1), perennial ryegrass (T2), timothy (T3) and Italian ryegrass (T4). Grass composition rate of different seed mixtures was decreased mostly at first year of grazing, like 44.9% of orchardgrass in T1 plot, 27.6% of perennial ryegrass in T2 plot, 40.9% of timothy in T3 plot and 40.7% of Italian ryegrass in T4 plot, respectively. Main species in seed mixture were decreased in grazing pasture, but kentucky bluegrass and tall fescue were increased in all plots. Italian ryegrass in T4 plot was well grown in early grown stage and inhibited the growth of other grass species, and 44.2% of Italian ryegrass was maintained in second year in the grazing plot. Average dry matter yields of first you showed 6,673 kg/ha and second year was 10,177 kg/ha. Average TDN yields of different seed mixtures were 6,399 kg/ha in T1, 7,769 kg/ha in T2, 4,383 kg/ha in T3 and 7,146 kg/ha in T4 plot. Average herbage dry matter intakes by different seed mixtures during 2 years were 5,937 kg/ha in T1, 6,375 kg/ha in T2, 4,925 kg/ha in T3 and 6,456 kg/ha in T4. This result indicated that perennial ryegrass would recommended in main species of Hanwoo grazing pasture.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.37-55
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• 2000

Two-dimensional numerical experiments and field surveys have been conducted to clarify some environmental variations in the flow and sedimentation in the adjacent seas after the construction of a tidal embankment. Velocities of flow and water levels in the bay decreased after the construction of the barrage. When the freshwater was instantly released into the bay, the conditions of flow were unaltered, with the exception of a minor variation in velocities and tidal levels around the sluices at the ebb flow. The computational results showed that freshwater released at the low water reached the outside of the bay and then returned to the inside with the tidal currents at the high water. The front sea regions of the embankment had a variety of sedimentary phases such as a clayish silt, a silty clay and a sandy clayish silt. However, a clayish silt was prevalent in the middle of the bay. On the other hand, the skewness, which reflects the behaviour of sediments, was $\{pm}0.1$ at the front regions of the embankment while it was more than ±0.3 in the middle of the bay. Analytical results of drilling samples acquired from the front of the sluice gates showed that the lower part of the sediments consists of very fine silty or clayish grains. The upper surface layer consisted of shellfish, such as oyster or barnacle with a thickness of 40～50 cm. Therefore, it seemed that the lower part of the sediments would have been one of intertidal zones prior to the embankment construction while the upper shellfish layer would have been debris of shellfish farms formed in the adjacent seas after the construction of the embankment. This shows the difference of sedimentary phases reflected the influence of a tidal embankment construction.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.3-12
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• 2000

The field surveys and the measurements of seawater temperatures were conducted every month from 1997 to 1999, and the distributions of seawater temperature were simulated and reproduced by a three dimensional hydrodynamic numerical model over the southern waters of Cheju island. In order to estimate the marine environmental capacity for the reception of the heat loads of cooling water discharged from Hwasoon Thermal Power Plant(HTPP) in the study area, the simulations for predicting the situation of unfavorable environment in which marine organisms might not be satisfied with change in seawater temperature were peformed using a three dimensional hydrodynamic numerical model by controlling quantitatively the heat loads of cooling water from HTPP Currently, HTPP discharges cooling water of 35.9℃ into the sea as much as 112,800m³/day in summer. As the results of simulations, the more the heat loads from the power plant increase, the more increase the seawater temperatures around the water areas adjacent to the power plant. In case the heat loads of cooling water from HTPP become about 5 times as high as the present loads, seawater temperatures at near-shore waters adjacent to HTPP appear to be increased to the extent of 0.5℃ above the existing seawater temperature in summer. The marine environmental capacity for the reception of thermal discharge from HTPP is estimated to be about 530×10/sup 6/kcal/day which is equivalent to the increase of a factor of 2 in the temperature of cooling water without any change in the discharge rate of cooling water or which is equivalent to the increase of a factor of 4.6 in the discharge rate of cooling water without any change in the temperature of cooling water. Comparing the case of the increase in the discharge rate of cooling water with the case of the increase in the temperature of cooling water on the basis of the same heat loads of 530×10/sup 6/kal/day, the former case is expected to increase seawater temperature a little higher and to extend the area affected by heat loads a little broader.

• Clinical and Experimental Pediatrics
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• v.46 no.9
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• pp.865-870
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• 2003

Purpose : We measured the umbilical cord arterial concentrations of isoprostane($8-iso-PGF_{2{\alpha}}$) and intended to decide whether the umbilical cord arterial concentrations of isoprostane could be used as a useful parameter for lipid peroxidation in newborn infants. Methods : The isoprostane and malondialdehyde(MDA) concentrations of the umbilical cord were measured by enzyme immunoassay and TBARS(thiobarbituric acid reactive substance) assay in 33 preterm and 28 term infants, respectively. The concentrations of isoprostane and MDA were compared between preterm infants and term infants, and were analysed for association with perinatal risk factors and neonatal complications. Results : Umbilical cord arterial concentrations of isoprostane were $704.7{\pm}635.6pg/mL$ and $421.9{\pm}306.5pg/mL$ in preterm and term infants, respectively. Umbilical cord arterial concentrations of MDA were $44.0{\pm}22.9{\mu}M/L$ and $26.2{\pm}10.7{\mu}M/L$ in preterm and term infants, respectively. Umbilical cord arterial concentrations of isoprostane and MDA in preterm infants were significantly higher than those in term infants(P<0.05). The umbilical cord arterial concentrations of isoprostane were significantly associated with perinatal risk factors such as fetal distress, oligohydramnios, and breech delivery in preterm infants and pregnancy-induced hypertension in term infants(P<0.05). Conclusion : Umbilical cord arterial concentrations of isoprostane in preterm infants were higher than those in term infants, and those are significantly associated with some perinatal risk factors.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1253-1259
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• 2003

Backgroud : Seizures in the neonate are relatively common and their clinical features are different from those in children and adults. The study aimed to provide the clinical profiles of neonatal seizure in our hospital. Methods : A total of 41 newborns with seizures were enrolled in this study over a period of three years. They were evaluated with special reference to risk factors, neurologic examinations, laboratory data, neuroimaging studies, EEG findings, seizure types, response to treatment, and prognosis, etc. Results : The average age at onset of seizures was $6.1{\pm}4.6days$ and the majority of patients(42%) had multifocal clonic seizure and 24% had subtle seizure. Factors that are known to increase risk of neonatal seizures include abnormal delivery history, birth asphyxia, and electrolyte imbalance, etc. However, they remain obscure in about 20% of cases. More than 50 percent showed abnormal lesions on neuroimaging studies such as brain hemorrhage, periventricular leukomalacia, brain infarction, cortical dysplasia, hydrocephalus, etc. and 17 out of 32 patients showed abnormal electroencephalographic patterns. Phenobarbital was tried as a first line antiepileptic drug and phenytoin was added if it failed to control seizures. The treatments were terminated in the majority of patients during the hospital stay. The overall prognosis was relatively good except for those with abnormal EEG background or congenital central nervous system malformations. Conclusion : Neonatal seizures may permanently disrupt brain development. Better understanding of their clinical profiles and appropriate management may lead to a reduction in neurological disability in later childhood.