• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.320-330
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• 2006

An integrated health of a lotic ecosystem, Cho River, was evaluated by various approaches such as conventional water quality analysis, physical assessments of Qualitative Habitat Evaluation Index (QHEI), and the bioassay of Index of Biological Integrity (IBI) durin August${\sim}$September 2005. The IBI model used in the study was based on original multivariate metric model and then modified the metric attributes of the model for the regional application. Physical habitat health, based on the QHEI, was estimated using eleven metrics. During the study, values of IBI model averaged 36, which was judged as 'fair' to 'good' conditions. Spatial variations in the model values were evident: the headwater site (S1) was estimated as 48, indicating an 'excellent' condition, and the other sites were estimated 32${\sim}$38, 'good' condition. Values of the QHEI in the all sites averaged 148, which is judged as a good condition. The QHEI values varied from 120 (fair condition) to 199 (excellent condition) depending on the location of the stream. Site 5 (S5) was estimated as 'fair${\sim}$good' condition, while Site 7 (S7) was estimated as 'excellent' condition. The biological health, based on the IBI, reflected the habitat health. However, chemical conditions in terms of pH, turbidity, electric conductivity, dissolved oxygen (DO) did not make a difference in the biological health because of minor chemical differences among the locations.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.77-93
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• 2000

Field survey on the spatio-temporal distribution of water quality and chlorophyll a concentration, and the environmental factors on the variation of phytoplankton biomass were carried out at the 23 stations for four seasons in the Shiahae, southwestern coast of Korean Peninsula from February to October in 1995. I made an analysis on biological factor as chlorophyll a concentration as well as environmental factors such as water temperature, salinity and nutrients; ammonia, nitrite, nitrate, dissolved inorganic nitrogen, phosphate, N/P ratio, silicate and Si/P ratio. The waters in the Shiahae were not stratified due to the tidal mixing and high velocity of tidal current. And the high productivity in photic layer were supported by high nutrients concentration from freshwater on lands and bottom waters The low depth of transparency in the Shiahae had a bad influence upon primary production and marine biology. In Shiahae had a sufficient nutrients for primary production during a year. Especially dissolved inorganic nitrogen and silicate were high, the other side, phosphate was low. The source of nutrients in summer and silicate supply depend on input of freshwater from lands, the other side, dissolved inorganic nitrogen and phosphate were depend on rather supplied from bottom layer by the mixing and input of seawater from outside than input of freshwater from lands. Phosphate seemed to become a limiting nutrient for the primary production at all area of Shiahae in winter and at the northern parts in other seasons. However, dissolved inorganic nitrogen seemed to do it at the southern parts in other seasons except winter. Silicate didn't become a limiting nutrient for diatoms in Shiahae. Phytoplankton biomass as measured by chlorophyll a concentration was very high all the year round, it was controlled by the combination of the several environmental factors, especially of nitrogen, phosphorus and the physical factors such as light intensity. [Spatio-temporal distribution, Seasonal fluctuation, Nnutrients, Chlorophyll a, Environmental factors, Nutrient source, Limiting Nutrient, Light, Shiahae] .

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.247-253
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• 2008

This study was performed to evaluate change of lipid oxidation, microbes, and color of chicken meat containing 6, 8, and 10% of water uptake rate(WUR) during cold storage. pH of chicken containing 6, 8, and 10% of WUR showed 6.00, 6.04, and 6.05%, at day 3, respectively. Lightness($L^*$) of chicken containing 6, 8, and 10% of WUR was 73.40, 75.27, and 75.31, at day 3, respectively. Redness($a^*$) of chicken with 10% of WUR was 2.52, which was the highest value, while no difference was found between chicken with 6 and 8% of WUR. Yellowness($b^*$) of chicken containing 6, 8, and 10% of WUR was 4.31, 4.33, and 4.36. Thiobarbituric acid reactive substances(TBARS) value of chicken containing 6, 8, and 10% of WUR was 0.107, 0.104, and 0.113 mg malondialdehyde/kg meat. The higher WUR, the higher TBARS value was shown. Total microbial number of chicken with 6, 8, and 10% of WUR was 4.04, 4.12, and 4.56 $log\;CFU/cm^2$ at day 3. E. coli of chicken with 6, 8, and 10% of WUR was 0.93, 1.40, and 1.28 $log\;CFU/cm^2$. From this result high WUR increases $L^*$ value, TBARS, and microbes of chicken meat during storage. Therefore, lower WUR would be beneficial to extend shelf life of chicken meat during storage.

• Journal of radiological science and technology
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• v.34 no.3
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• pp.239-244
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• 2011

In this study, we evaluated diffusion weighted imaging (DWI) to investigate whether the DWI parameters can predict characteristic parameters on pathologic specimens of tumor or not. CFPAC-1 was injected subcutaneously on the back flank of athymic nude mice (n=13) then two tumors were initiated on each mouse (2${\times}$13=26 tumors). The mice were sacrificed to make specimen immediately after initial MR imaging then were compared with the MR image. A dedicated high-field (7T) small-animal MR scanner was used for image acquisitions. A T1 and T2 weighted axial image using RARE technique was acquired to measure the T2 values and tumor size. DWI MR was performed for calculating ADC values. To evaluate tumor cellularity and determine the levels of MVD, tumor cells were excised and processed for H-E staining and immunostaining using CD31. T2 values and ADC values were computed and analyzed for each half of the tumors and compared to the correlated specimens slide. Median ADC within each half of mass was compared to the cellularity and MVD in the correlated area of pathologic slide. The mean of ADC value is $0.7327{\times}10^{-3}$ $mm^2/s$ and standard deviation is $0.1075{\times}10^{-3}$ $mm^2/s$. There is a linear relationship between ADC value and tumor necrosis (R2=0.697, p< 0.001). DW image parameters including the ADC values can be utilized as surrogate markers to assess intratumoral neoangiogenesis and change of the internal structure of tumor cells.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.179-188
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• 1994

This study was conducted to investigate the distribution of potassium fractions and to establish the soil chemical indices for assessing potassium availability in upland soil. Soil samples were collected from 66 vegetable crop fields of Chungbuk Jungweon, Jeonbuk Imsil and Kyengbuk Euiseong and these samples were analyzed water soluble(W. S. -K), exchangeable(Exch. -K) and nonexchangeable potassium(Nonex. -K). The distribution of potassium fractions was examined for soils having different physico-chemical properties and compared with the soil parameters related to the potassium availability. 1. The distribution ranges of W.S.-K, Exch.-K and Nonex.-K were 0.07~1.42, 0.27~2.30, and 0.84~4.74me/100g, and average contents of relevent fractions were 0.40, 1.03 and 2.37me/100g respectively. 2. Contents of W.S.-K and Exch.-K were decreased with increasing soil pH, CEC, Exch. Ca and Exch. Mg contents but Nonex. -K showed a low correlationship with these factors. 3. Exch.-K content slightly inereased with increasing clay content, while W.S.-K and Nonex. -K contents were grandually decreased with clay contents. 4. The relationship between W.S.-K and Exch.-K was significant and W.S.-K was released from soil at 0.23me/100g content of Exch.-K 5. Contents of W.S-K and Exch.-K showed high correlationship with soil chemical parameters such as ratio of exchangeable cations(K/Ca+Mg), ratio of exchangeable cation equivalent[$K/{\sqrt{Ca+Mg}}:(me/100g)^{1/2}$], potassium exchangeable free energy(${\Delta}F=RT$ 1n $K/{\sqrt{Ca+Mg}}$ : calories/mole) and saturation percentage of potassium($Exch.K/CEC{\times}100$), and these factors were considered to be good parameters for assessing soil potassium availability.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.983-991
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• 2012

These days, agricultural products cultivated in facilities occupy the highest percentage of agricultural output price. Specifically cucumbers have been one of the crops that farmers prefer to growing, because their prices were high. However, cucumber crop is sensitive to the soil and environments and it requires the exact crop management. In order to establish cultivation techniques for cucumbers, the current situation of cucumber cultivation was surveyed from ten cucumber farmlands; five farmlands of cucumber cultivation in forcing and five of semi-forcing practicing systems, respectably. The soil conditions were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy in soil texture family. Soil was managed with deep plowing combined with application of basal fertilizers such as compost, rice straw, oil cake, wood chip and chemical fertilizer. The whole soil was prepared in uniformly with rotary. Three major nutrients ($N-P_2O_5-K_2O$)of basal application were 815-464-529 kg $ha^{-1}$ in forcing and 197-135-151 kg $ha^{-1}$ in semi-forcing cultivation. Top dressing of fertilizer was supplied in fertigation system of macro and micro elements in 2~3 day interval with water irrigation. The average yields of cucumbers were $168t\;ha^{-1}$ with 381,000 thousand won $ha^{-1}$ in average gross profit (AGP) in forcing cultivation and $115t\;ha^{-1}$ with 177,000 thousand won $ha^{-1}$ in AGP in semi-forcing cultivation. Cucumber production during the winter season was considered to increase the gross profit because cucumber price tends to stay in high level during this time. The accumulation of soil chemicals like EC, available $P_2O_5$ and exchangeable cations could be controlled by rice straw application. The rice straw application increased soil temperature during the winter season, in exchange of soil air, and in extension of plant roots. In addition, the rice straw application somewhat affected decrease of salts accumulation.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.200-208
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• 2010

The objectives of this study were to evaluate no-tillage cover crop cropping systems for organic farming in paddy. The experiment was performed at Ihyeon series (silt loam: 9.1% sand, 73.0% silt and 17.9% clay) which affected by different management practices. Planthopper population per 20 plant was significantly higher 65.3 for conventional tillage with chemical compounds (control) compared with 3.4~9.6 for no-tillage treatments (without rice straw or green manure, amended with rice straw, hairy vetch, rape, rye, and Chinese milk vetch). Also, disease severity of sheath blight was significantly higher 10.5% for control compared to 0.7~2.9% for no-tillage treatments. Four weed species, namely Monochoria vaginalis, Ludwigia prostrata, Rotala indica, and Aneilema keisak occurred in no-tillage paddy, whereas Monochoria vaginalis occurred in control only. The pH, available phosphate, and microbial biomass C in paddy were steeply decreased in response to submerging, but increased at first heading stage. Soil $NH_4$-N content at first heading stage was significantly higher in no-tillage treatments compared with control. The grain yield was significantly higher in 4.30 Mg $ha^{-1}$ for control than other treatments. Meanwhile, rice productivity was significantly higher in 2.69 Mg $ha^{-1}$ for no-tillage amended with Chinese milk vetch compared to other no-tillage treatments. The number of panicle per plant, grain number perpanicle, and percent ripened grain were highly related for increasing the yield of rice. These results show that Chinese milk vetch was optimum cover crop for organic farming in no-tillage paddy.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.115-120
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• 1999

This experiment was carried out to investigate the effects of additives on the quality of alfalfa(Medicago sativa L.) silage at the forage experimental field, National Livestock Research Institute, RDA, Suwon in 1996. The experiment was arranged in a randomized block design with three replications. The treatments consisted of different additives(control, formic acid, molasses, inoculant A and inoculant B). Crude protein(CP) and Nitrogen free extract(NFE) content of alfalfa silage with additives were higher compared with those obtained control, but Crude ash(CA) and Crude fiber(CF) content of control(11.5 and 39.6%) were higher than those of additive treated plots. ADF and NDF contents of control silage were the highest as 36.2 and 48.6%, respectively, and increased by 4% compared with those obtained before ensiling. The acidity(pH) of control was the highest(5.45), but the lowest in inoculant A(4.32). Inoculant teratment significantly reduced acidity of silage compared with control. DM content of control silage was the lowest but DM loss of control silage was higher than that of additive treated silage. Ammonia-N content was the highest at formic acid treatment and level of Lactobacillus was decreased at control and formic acid treated silage. Total organic acid and lactic acid content of inoculant A and inoculant B were higher than those of other treated plots. The results of this study indicate that the treatment of LAB(Lactic acid bacteria) could be recommended as producing high quality of alfalfa silage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.2
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• pp.113-126
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• 1988

Paralytic shellfish poison(PSP) accmulate in shellfish as a result of feeding toxic dinoflagellates. The shellfish do not seem to be harmed by the toxins, but become toxic to humans and other animals that feed on them. The purpose of this study was to investigate the distribution and changes of PSP by species of shellfish, collected area and collected month. Also, the correlation between PSP and toxic dinoflagellate, Protogonyaulax tamarensis, was investigated. Five hundred and six samples of 13 kinds of shellfish for PSP bioassay were collected at the shellfish growing area of Pusan, Masan, Chungmu, $Samch\check{o}npo, Y\check{o}su, Mokpo and Daech\check{o}n$ located in South Korea during the study period from May, 1985 to Octcber, 1987. Most of the samples submitted were free from PSP except sea mussel, short - necked clam and ark shell. Among the intoxicated samples, PSP was most often detected in sea mussel. PSP was detected mainly in spring$(February\~May)$ in the southern coast of Korea. In case of Pusan, exceptionally, toxic sea mussel have been found even June and July in 1987. The toxicity score of toxic shellfishes examined was ranged from 23.44 to $150.26{\mu}g/100g$ of edible meat and toxicity of sea mussel was higher than other toxic shellfishes. By the study of anatomical distribution of PSP in sea mussel collected at Masan in Febuary and March, 1986, the toxin accumulated in digestive gland was about $70\%$ of all. There was no significant correlation between toxicity of sea mussel and cell numbers of P. tamarensis that one of the causitive organism of PSP during the studying period in Masan area. There was almost no difference in toxicity of sea mussel by water depth of collection, but toxicity of surface shellfish was a little higher than those of 3.5, and 7.0m depth.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.109-119
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• 2006

This study investigated the effect of artificially enhanced mesozooplankton on the phytoplankton dynamics during fall blooming period using a mesocosm in Jangmok bay located in the Southern Sea of Korea in 2001. The four bags with 2,500 liter seawater containment were directly filled with the ambient water. And then, abundances of mesozooplankton in two experimental bags were treated 6 times higher than those in control bags by towing with net($300{\mu}m$) through the ambient water. Phytoplankton community between control and experimental bags were not significantly different in terms of chlorophyll-a(chl-a) concentration and standing crop (one-way ANOVA, p>0.05) during the study period. Initial high standing crop and chl-a concentration of phytoplankton drastically decreased and remained low until the end of the experiment in all bags. Diatoms, accounting for most of the phytoplankton community, consisted of Skeletonema costatum, Pseudo-nitzschia seriata, Chaetoceros curvisetus, Ch. debilis, Cerataulina pelagica, Thalassiosira pacifica, Cylindrotheca closterium, and Leptocylindrus danicus. Noctiluca scintillans dominated the temporal variation of mesozooplankton abundances, which peaked on Day 10 in the control and experimental bags, while the next dominant copepods showed their peak on Day 7. Shortly after mesozooplankton addition, copepod abundance in the experimental bags was obviously higher than that in the control bags on Day 1, however, it became similar to that in the control bags during the remnant period. It was supported by the higher abundance and length of both ctenophores and hydromedusae in experimental bags relative to the control bags. However, the cascading trophic effect, commonly leading to re-increase of phytoplankton abundance, was not found in the experimental bags, indicating that copepods were not able to control the phytoplankton in the bags based on the low grazing rate of Acartia erythraea. Besides that, rapidly sunken diatoms in the absence of natural turbulence as well as N-limited condition likely contributed the no occurrence of re-increased phytoplankton in the experimental bags.