• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.3
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• pp.88-102
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• 2017

Long-term changes in bathymetry and grain size of surface sediments were investigated for understanding depositional sedimentary environments in the channelized Yeongsan River Estuary, Korea. The results revealed that an average depth of the estuary had decreased up to 2.1 m from 1982 to 2006, while it had increased to 0.3 m from 2006 to 2012. The rapid decrease of the water depth from 1982 to 2006 was due to the vast deposition of mud caused by the change of water course and flow velocity after the estuary was dammed. Meanwhile the increase of the water depth from 2006 to 2012 may be associated with multiple erosional processes, including a dredging at the southern part of the estuary and other erosions from the dike sluice expansion work. Considering the water-depth change and tidal-level variation in the study area, an depositional rate in the estuary is estimated to be 8~9 cm/yr for the last 2 decades (1982~2006). The sediments of Yeongsan River Estuary are largely composed of silt-clay mixtures: overall, silt is distributed mainly in the shallow area of the estuary edge, while clay is confined to the deep area of the estuary center. Mean grain size of the sediments is 6.0 Ø on average in 1997, 7.8 Ø on average in 2005 and 7.7 Ø on average in 2012, respectively, suggesting that the sediments became finer due to the increase of silt and clay contents in 1997~2005. Furthermore, several lines of evidences, including the comparison between the amounts of the sediment influx discharged from the Yeongsan River and the sediments in the estuary, and the changes in distribution pattern of silt and clay contents implying that they moved from offshore to estuary dike, indicate that the mud sediments are originated mainly from the offshore, not from the river.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.148-155
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• 2024

This study investigated the ecological characteristics of Odontobutis platycephala at Jaho stream from January to December 2022. The riverbed structure of the species' habitat was rich in cobble and pebble. The water was deep, ranging from 22 to 153 cm, with an average of 64 cm, and the stream velocity was rapid at 0.89 (0.42-1.46) m/sec. The ratio of females to males was 1:1.02, and the total length of collected individuals ranged from 38 to 156 mm. The age according to the total length frequency distribution as of May indicated that the group with a total length of 38-69 mm was one year old, the group with 60-99 mm was two years old, the group with 100-139 mm was three years old, and the group 140-156 mm was four years or older. As a secondary gender characteristic, the genital papilla was cylindrical in females and cone-shaped with a pointed tip in males. Some females with a length ranging from 60 to 69 mm and all females 70 mm or longer were sexually mature. Some males with a length ranging from 70 to 79 mm and all males 80 mm or longer were sexually mature. The spawning season was from May to July, and the water temperature was between 17 ℃ and 28 ℃ during that period. The prosperous spawning season was June (24 ℃). The average number of eggs in the ovaries was 988 (284-2,722) per mature female, and the mature eggs were yellowish and spherical with a mean diameter of 1.46 (1.19-1.71) mm. The correlation between total length and body weight is BW=0.00000006TL^3.12 with the constant a as 0.00000006 and the parameter b as 3.12. The mean condition factor (K) was 1.44 (0.96-2.26), and the slope was negative at -0.0007

• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.298-305
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• 2005

Purpose : We performed this study to evaluate the mean serum levels of insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein(IGFBP)-2 and IGFBP-3 in healthy Korean children according to age and sex. Methods : Ninety two healthy children, consisting of 42 boys and 50 girls, were classified into five groups according to age : neonate; infancy; early childhood; late childhood; and adolescence. We measured serum levels of IGF-I, IGFBP-2 and IGFBP-3 by enzyme-linked immunosorbent assay(ELISA) and analysed the serum levels according to sex and age group. Results : For boys, the mean serum levels of IGF-I(ng/mL) in neonate, infancy, early childhood, late childhood and adolescence were $41.1{\pm}3.6$, $70.9{\pm}33.7$, $103.5{\pm}97.2$, $89.8{\pm}46.5$ and $51.4{\pm}27.8$, respectively. Those of IGFBP-2(ng/mL) were $8.2{\pm}3.4$, $5.8{\pm}0.4$, $9.3{\pm}4.0$, $9.5{\pm}1.1$ and $7.0{\pm}0.5$, respectively. Those of IGFBP-3(ng/mL) were $559.2{\pm}215.2$, $1,333.3{\pm}692.5$, $2,254.6{\pm}1,513.8$, $2,447.1{\pm}1,464.2$, $1,533.6{\pm}807.4$, respectively. For girls, the mean serum levels of IGF-I(ng/mL) according to five age groups were $53.3{\pm}9.5$, $99.3{\pm}45.8$, $69.6{\pm}51.1$, $106.2{\pm}67.0$ and $145.1{\pm}127.8$, respectively. Those of IGFBP-2 (ng/mL) were $9.1{\pm}7.4$, $5.3{\pm}0.9$, $6.9{\pm}2.0$, $10.5{\pm}3.0$ and $7.9{\pm}1.3$, respectively. Those of IGFBP-3(ng/mL) were $858.2{\pm}433.4$, $1,834.8{\pm}851.3$, $1,404.3{\pm}570.2$, $2,203.5{\pm}899.4$ and $2,029.3{\pm}1,316.7$, respectively. There were significant positive correlations observed between IGF-I and IGFBP-3 levels(r=0.589, P=0.000). Conclusion : IGF-I and IGFBP-3 levels increased as children get older. The peak level of IGFBP-3 was observed in late childhood for both boys and girls, suggesting a current trend of children reaching peak growth velocity before adolescence. The IGFBP-2 level was higher in neonates compare to infancy, suggesting that IGFBP-2 is an important substance for fetal growth.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.75-82
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• 1999

This study was carried out to examine the effect of day/nignt temperatures during seedling culture on the vegetative and reproductive growth of Lycopersicum esculentum ‘Seokwang’. The study was consisted of two culture stages, plug seedling production in the growth chamber and hydroponic culture of the plant in a glasshouse. Experiments were replicated over time. The germinated seedlings were raised for 33 days (experiment 1) and 35 days (experiment 2) in 4 growth chambers, each with day/night temperatures of either $25^{\circ}C$/$25^{\circ}C$, 16$^{\circ}C$/16$^{\circ}C$, 16$^{\circ}C$/$25^{\circ}C$ or $25^{\circ}C$/16$^{\circ}C$. Cool-white fluorescent lamps provided 140$\mu$mol.m$^{-2}$ .s$^{-1}$ light for 12h each day. In the second experiment, all chambers were supplied with 1000$\mu$mol.mol$^{-1}$ CO$_{2}$ during the photoperiod and had an air velocity of 0.3m.s$^{-1}$ and relative humidity of 80%. Plug seedlings raised were transplanted to rockwool slabs in a glasshouse and were grown hydroponically using the same nutrient solutions used for seedling culture for 37 days (experiment 1) and 35 days (experiment 2). Plant height was affected more by mean daily temperature than by interaction of day and night temperatures. Plant height was the highest in 16/16$^{\circ}C$ treatment. Leaf count was not affected by day and night temperatures, and the chlorophyll concentration was the highest in 16/$25^{\circ}C$ treatment. Fresh and dry weights of stem tended to be greater in treatments of constant day and night temperature. The number of node on which first and second flower clusters were set was significantly higher in 25/$25^{\circ}C$ treatment than in the other treatments. Days to flower of the first flower on the first flower cluster were the greatest in 25/$25^{\circ}C$ and the least in 16/$25^{\circ}C$ treatment. Vegetative and reproductive growth, such as height, fresh and dry weights, days to flower, and nodes of the 1st and 2nd flower cluster set were affected by day/night temperatures.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.922-929
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• 2009

Purpose : The aim was to investigate the clinical characteristics and responses to growth hormone (GH) therapy in children with attenuated growth who showed normal GH responses to GH stimulation tests (GHST). Methods : The study included 39 patients with height velocity (HV) of less than 4 cm/yr and normal GHST results. Clinical characteristics of patients were analyzed retrospectively. Results : Eleven were born as small for gestational age (SGA) and 28 as appropriate for age (AGA). In the SGA group, the standard deviation score (SDS) of age and height measured at their first visit was significantly low. Sixteen patients were treated with GH and six of 23 without GH therapy were followed for 1 year after GHST. The mean (range) of HV was 7.7 (4.9 to 11.1) cm/yr in patients with GH therapy and 3.7 (2.7 to 4.5) cm/yr in those without GH therapy, which was statistically significant (P<0.001). In the GH-treated group, HV and difference in height SDS during the treatment increased significantly (P<0.001; P< 0.001, respectively). HV increased after 1 year of GH therapy in the SGA and AGA groups (SGA, P=0.043; AGA, P=0.003). The level of Insulin-like growth factor-I was significantly lower in GH-treated patients with height SDS <-3 than those with ${\geq}3$ (P=0.023). Conclusion : In children with growth failure and normal GHST, HV increases significantly by short-term GH therapy. The assessment of long-term effects of GH therapy is necessary. Moreover, further studies should be considered to evaluate the GH-IGF-I axis due to the possibility of GH insensitivity syndrome.

• Journal of Aquaculture
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• v.5 no.1
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• pp.93-108
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• 1992

This study was conducted to understand the variation of suspended matters in coastal waters of Cheju Island. Water sampling was carried out at 22 stations along the coast of this island from March 1988 to November 1989. Analyzed and/or observed items were water temperature, salinity, total solids (TS), total dissolved solids (TDS), volatile suspended solids (VSS), and fixed suspended solids (FSS). Inter-relationships between wind velocity, precipitation and total suspended solids (TSS) were also investigated. More windy days prevail in winter season (December, January and February) in Cheju Island. Thirty-six points seven percent of total windy days of a year appeared in this season. The rate of windy days in spring was $27.3\%$ and those in summer and fall were $17.9{\%}$ each. From February to July, the heaviest precipitation was observed in the southeastern area and that from August to January was observed in the eastern part of this island. TS and TDS were firmly related with the fluctuation of salinity. Therefore, there were higher in spring and lower in summer. The highest TSS (7.73 $mg/{\ell}$) was observed in February and was the lowest (4.73 $mg/{\ell}$) in September. Annual mean value of TSS was 6.3$mg/{\ell}$. The highest VSS (2.03 $mg/{\ell}$) was observed in July and lowest (1.42 $mg/{\ell}$) in September. The percentage of VSS per 755 was $30.6{\%}$ in average that was not much higher level compared to the other polluted areas. This value became higher in summer (av. $34.17{\%}$) and lower in winter (av. $24.2{\%}$). Fluctuation of TSS was mainly related with the freshwate. discharge, tidal action, and re-suspension of bottom sediments by the wind waves. Therefore, TSS concentration was low in summer and hish in winter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1278-1286
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• 2008

The effect of Tween 20 addition on changes in the stability of methylcellulose (MC) emulsions (1 wt% MC, 10 wt% n-tetradecane, 20 mM bis-tris buffer, pH 7) was investigated by creaming stability and orthokinetic stability measurements. In the case of MC emulsions containing varying amounts of oil (1$\sim$30 wt%) and no Tween 20 added, creaming stability, judged by mean migration velocity of fat globules ($V_m$), was found to depend on droplet size: the larger the droplet size, the worse the stability [$V_m$: 0.326 $\mu$m $min^{-1}$ ($d_{32}$: 0.32 $\mu$m) ${\rightarrow}V_m$: 0.551 $\mu$m $min^{-1}$ ($d_{32}$: 0.53 $\mu$m)]. With Tween 20, creaming stability was found to be worse than the one without Tween 20, except for MC emulsion containing 0.2 wt% Tween 20. In addition, cream stability was the lowest with the lowest concentration of Tween 20 and a tendency to recover with increasing Tween 20 concentration [$V_m$: 0.598 $\mu$m $min^{-1}$ (0.01 wt%)${\rightarrow}V_m$: 0.389 $\mu$m $min^{-1}$ (0.2 wt%)] was found. From viscosity measurement for aqueous bulk phase of MC emulsions, such a change in the creaming stability was found to coincide well with the results of viscosity measurement. Therefore, it was reasonable to say that creaming stability of MC emulsions containing Tween 20 depended on MC concentration in aqueous bulk phase, which was in turn varied by competitive adsorption between MC and Tween 20 at the oil droplet surface. In case of orthokinetic stability, judged by destabilization time ($t_d$), it was found that the addition of Tween 20 resulted in lowered stability with more pronounce tendency at higher concentrations [$t_d$: 160 min (0.03 wt%)${\rightarrow}t_d$: 100 min (0.2 wt%)]. Moreover, combined with previous results, the orthokinetic stability of MC emulsions containing Tween 20 was found to be exponentially proportional to MC load. In conclusion, competitive adsorption between MC and Tween 20 may affect the stability properties of MC emulsion to varying extents, depending on the concentration of Tween 20.

• The Korean Journal of Food And Nutrition
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• v.16 no.3
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• pp.171-179
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• 2003

In order to investigate the effects of pickle carrier on physico-chemical characteristics of seasoning chicken products, chicken were cured in seasoning containing 100 ppm germanium water, green tea, water soluble mineral and mixtures(100 ppm germanium water+green tea+water soluble mineral) after addition of 0.1% concentration to the weight of chicken. The determination of pH, salt and sugar contents were carried out, according to curing time. The salt content showed 1.11 %, 1.21 % in cured at 24 hours in control of breast and leg, irrespective of chicken parts, in which showed 19.94 brix, 18.89 brix in sugar content, respectively. These results mean that breast and leg meat added with natural extracts and functional water showed higher sugar content than that of control, in which revealed shortening of curing time by increasing penetrating velocity of salt and sugar content. Thus, salt and sugar content tended to be increased as the curing time of pickle carrier were extended in seasoning chicken after dipping in pickle containing water soluble mineral ions for 6 hours. The seasoning chicken treated with natural extracts and functional water showed a lower than that of control in hardness, irrespective of chicken parts. Overall, the seasoning chicken treated with natural extracts and functional water showed a low TBARS value and Log CFU/g, in which revealed antioxidative and antimicrobial activity. The sensory evaluations of seasoning chicken added with natural extracts and functional water containing water-soluble mineral ions were not significantly different(P<0.05). The glutamic acid among free amino acid contents showed a high in seasoning chicken treated with green tea, compared to control. This amino acid played a important role in taste of seasoning meat. The doneness appearance in seasoning chicken added with natural extracts and functional water containing water-soluble mineral ions tended to not be different, compared to those of control. These results revealed that seasoning chicken added with natural extracts and functional water containing water-soluble mineral ions would be attractive in fast food market on the basis of improvement of tenderness, shortening of curing time and uniformity of roasting appearance in seasoning chicken.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.4
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• pp.206-216
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• 2017

The temporal distribution of the turbulence kinetic energy (TKE) and the vertical component of Reynolds stresses ($-{\bar{u^{\prime}w^{\prime}}}$) was measured during one wave period under high wave energy conditions. The wave data were obtained at Hujeong Beach in the east coast of Korea at January 14~18 of 2017 when an extratropical cyclone was developed in the East Sea. Among the whole thousands of waves measured during the period, hundreds of regular waves that had with similar pattern were selected for the analysis in order to give three representing mean wave patterns using the ensemble average technique. The turbulence properties were then estimated based on the selected wave data. It is interesting to find out that $-{\bar{u^{\prime}w^{\prime}}}$ has one clear peak near the time of flow reversal while TKE has two peaks at the corresponding times of maximum cross-shore velocity magnitudes. The distinguished pattern of Reynolds stress indicates that vertical fluxes of such properties as suspended sediments may be enhanced at the time when the horizontal flow direction is reversed to disturb the flows, supporting the turbulence convection process proposed by Nielsen (1992). The characteristic patterns of turbulence properties are examined using the CADMAS-SURF Reynolds-Averaged Navier-Stokes (RANS) model. Although the model can reasonably simulate the distribution of TKE pattern, it fails to produce the $-{\bar{u^{\prime}w^{\prime}}}$ peak at the time of flow reversal, which indicates that the application of RANS model is limited in the prediction of some turbulence properties such as Reynolds stresses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.700-707
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• 1997

In order to express exactly the total resistance of bottom trawl nets subjected simultaneously to the water flow and the bottom friction, the influence of frictional force was added to the formular for the flow resistance of trawl nets obtained by previous papev and the experimental data obtained by other investigators were analyzed by the formula. The analyzation produced the total resistance R (kg) expressed as $$R=4.5(\frac{S_n}{S_m})^{1.2}S\;v^{-1.8}+20(Bv)^{1.1}$$ where $S(m^2)$ was the wall area of nets, $S_m\;(m^2)$ the cross-sectional area of net mouths, $S_n\;(m^2)$ the area of nets projected to the plane perpendicular to the water flow, B (m) the made-up circumference at the fore edge of bag parts, and v(m/sec) the dragging velocity. From the viewpoint that expressing R in the form of $R=kSv^2$ was a usual practice, however, the resistant coefficient $k(kg{\cdot}sec^2/m^4)$ was compared with the factors influencing it by reusing the experimental data. The comparison gave that the coefficient k might be expressed approximately as a function of BL only and so the resistance R (kg) as $$R=18{\alpha}B^{0.5}L\;v^{1.5}$$ where L (m) was the made-up total length of nets and $\alpha=S/BL$. But the values of a in the nets did not deviate largely from their mean, 0.48, for all the nets and so the general expression of R (kg) for all the bottom trawl nets could be written as $$R=9\;B^{0.5}\;L\;v^{1.5}$$.