• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.87-97
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• 1995

Acute and chronic toxicity of phenol on the mortality, long-term survival and respiration rates of the mysid, Archaeomysis kokuboi adult and juvenile were examined. This experiment was condurted by static bioassay procedure with the different salinity at $25^{\circ}C$ In lethal test, the test animals were exposed to 6 different phenol concentrations to determine $LC_{50}$ and I$LT_{50}$ (median lethal concentration and time) values. The $LC_{50}$ values with the exposure time for the mysid adult ranged from 31.31ppm to 1.49ppm phenol and for the mysid juvenile ranged from 6.90ppm to 0.26ppm in all experimental groups. Mortality was increased with the decrease of salinity, The $96hr-LC_{50}$ values at 16, 24 and $32\%o$ salinity for the mysid adult were 1.49, 2.71 and 4.53ppm phenol, white the values for the mysid juvenile were 0.26, 0.56 and 0.71ppm, respectively. The ratios of $96hr-LC_{50}$ values for the mysid adult to those for the mysid juvenile at 16, 24 and $32\%p$ salinity were 5.73, 4.84 and 6.38, respectively. The mysid juveniles were more sensitive to phenol than the mysid adults. Compared $LT_{50}$ values for the mysid adult with those for the mysid juvenile, the $LT_{50}$ values for the mysid adult ranged from 384.7 to 29.0 hours at 1.7-127ppm phenol concentrations and for the mysid juvenile ranged from 132.2 to 18.7 hours at 0.5~6.Oppm phenol concentrations. The lowest $LT_{50}$ values for the mysid adult and juvenile were showed at the combination of the highest experimental concentration of phenol and the lowest experimental salinity. The mysid juveniles showed lower $LT_{50}$ values than those of adults. The chronic effects of phenol on the mysid at the sublethal effective concentration of phenol were lower in the $32\%o$ salinitr group than 16 or $24\%o$ salinity groups. Oxygen consumption rates of the mysid adult were decreased with the increase of phenol concentration and exposure time, and decreased significantly in lower salinity at the same concentration or phenol.

• Korean Journal of Organic Agriculture
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• v.24 no.3
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• pp.557-570
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• 2016

Growth of 6-year old 'Niitaka' pear (Pyrus pyrifolia Nakai) trees and control of insect and disease occurrences were compared between fermented soybean extracts and rain-shelter system for two years. Foliar application of fermented soybean extracts was applied at 6 times as a pre-experiment in the open-field in 2013, with a rain-shelter system in 2014. Fermented soybean extract treatment increased foliar concentrations of approximately 0.46% T-N, 0.17% K, 0.19% Ca, and 0.06% Mg in 2013 compared to the control, with similar macro-nutrients between the control and soybean extract treatment observed in 2014. Rain-shelter system increased foliar concentrations of T-N, Ca, and Mg compared to the open-field. There were no significantly different between the control and soybean extract treatment for number of leaves per fruit, leaf dry weight, phytotoxicity, and completed shoot growth on August during the two years. Rain-shelter system increased leaf dry weight and did not affect phytotoxicity in the leaves. Fruit quality parameters were mostly similar to control and soybean extract treatment for two years, with higher fruit firmness observed for soybean extract treatment. Rain-shelter system advanced 4 days of harvest dates, and increased approximately 7.0 ton fruit yield per ha, 20 g mean fruit weight, and fruit soluble solid contents compared to open-field in 2014. Soybean extract treatment little suppressed occurrence of disease and insect on the leaves and fruits in both years. Rain-shelter system increased occurrence of Venturia nashicola on the leaves and to 63.8% of Gymnosporangium asiaticum on the fruits in 2014. Strong winds and storms in May elevated relative humidity in the rain-shelter system and caused high infection of the disease occurrence, requiring for an additional green control method. Soybean extract treatment little affected tree growth and would have initiated for a long-term study to evaluate tree physiological characteristics. Rain-shelter system improved fruit productivity and advanced harvest dates, which could have been more effective facility at a Thanks Giving Day between middle and end of September.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.106-116
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• 2005

This experiment was conducted to investigate available extraction capacity and potential mobility of heavy metal according to the distribution property and contamination level of heavy metals in soils and to suggest a reform measure of soil environment assessment methodology applied with soil quality and the official soil heavy metal test methods in domestic and foreign countries. The soils were collected from the natural forest paddy with long-term application of same type fertilizer, and paddies near metal mine and industrial complex. The post-treatment methods of soil were partial extraction, acid digestion and sequential extraction methods. For the heavy metal contents with different soil properties, it was shown that their natural forest and paddy soil were slightly low and similar to the general paddy soil, while their paddies near metal mine and industrial complex were higher than the standard level of Soil Environment Protection Act. Heavy metal concentrations in the soils with different soil properties had difference between $HNO_3\;and\;HNO_3+HCl$ extractant by US-EPA 3051a method. There were highly significant positive relationships in both two methods. It was appeared that the higher extractable concentration ratio with 0.1N-HCl to total heavy metal content with $HNO_3+HCl$ extractant the greater total heavy metal content. There were highly significant positive correlationship between total heavy metal content and extractable content with 0.1N-HCl. For extractable capacity of soil extractable solution compared to the total heavy metal content it was appeared that it extractable method with 0.1N-HCl was higher than those with EDTA and DTPA. In extractable ratio with 0.1N-HCl in the contaminated paddy soils near mine and industrial complex, it was shown that the lower soil pH, the higher total heavy metal content. The order of a potential mobility coefficient by distribution of heavy metal content with ie different typies in the soil was Cd>Ni>Zn>Cu>Pb. It could be known that contamination characteristics of heavy metals with different types of soils were affected by different heavy metal components, contamination degree and soil chemical properties, and heavy metal concentration with different extractable methods had great variations with adjacent environment. To be compared with assessment methodology of soil environment impact at domestic and foreign countries with our results, it might be considered that there was necessary to make a single analysis method based on total heavy metal content with environmental overloading concept because of various analysis methods for total heavy metal content and present analysis method with great variation according to soil environment. In spite of showing higher concentration of heavy metal with acidic digestion than the extractable method, it might be considered that there is need to be adjusted the national standard of soil heavy metal contamination.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.250-257
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• 1997

Stem diameter and shoot fresh weight of tomato grown in greenhouse were measured non-destructively at 10 minutes interval from 1 to 16 July, 1996 with displacement detector using strain gauges and with suspension-type load cell, respectively, and simultaneously were measured soil water potential, transpiration and solar radiation. Ample water was irrigated before experiment, and thereafter, irrigations were made on the next morning when visual symptoms of wilting appeared. Shoot fresh weight and stem diameter showed very similar patterns in diurnal changes which are characterized by predawn maximum and afternoon minimum and in long- term evolutions, suggesting that stem diameter shrinkage and expansion are closely related to plant water content and growth, respectively, Shoot weight and stem diameter reached minimum values a little later than the time on which transpiration showed maximum. The daily net gains of fresh weight(DG) and stem diameter(DI) showed significantly Positive correlations with solar radiation in those days on which plants were not water-stressed. However, Dl and DG on those days of water stress showed much lower values than expected from the relationships between solar radiation and them. Transpiration was much lower than the expected potential transpiration on 10 July, implying that plants were water-stressed. In this case water stress was not detected from visual symptom of wilting and/or soil water potential, but was able to be identified by the lower DI and DG than the expected. The maximum contraction of stem diameter(MC) and the maximum loss of fresh weight(ML) during daytime showed significantly positive correlations with solar radiation in those days on which plants were not water-stressed and were observed greater than expected from the relationships on severely water-stressed days. But mild water stress could not be discernable by ML and MC. It would be concluded that the daily net gains of fresh weight and/or stem diameter could be used as criteria for diagnosing the water status of tomato and for triggoring the onset of irrigation in automatic system.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.161-167
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• 2011

The soil moisture has an important effect on growth and development of highbush blueberry (HB), mainly because the root system, devoid of root hairs, is superficial. Moreover, the texture and organic matter content of Korean soil is different from the main producing counties, such as USA and Canada. To facilitate the growth and development of HB and long-term maintenance of productivity, the research related to soil moisture condition in Korea should be the priority. This study was performed to investigate the growth properties of the HB in various soil moisture conditions in order to determine the irrigation trigger point and optimum soil water potential. The texture of soil used in this experiment was loam. For the experiments, the soil was mixed with peatmoss at a rates 30% (v/v). Irrigation was scheduled at -3, -4, -5, -8, -15 and -22 kPa soil water potential then investigated leaf macronutrient, bush growth, and fruit properties. The leaf K content of HB showed the same trend in the soil water potential, but Leaf P and Mg content was highest in -5 and -22 kPa, respectively. The productivity and growth amount of HB showed the peak at the range of -4~-8 kPa as normal distribution pattern, and greatly decreased at above -15 kPa. Total dry weight and Cane diameter were highest at -4 kPa, plant width, fruit weight and yield were highest at -5 kPa, and plant height, cane number and shoot tension were highest at -8 kPa. Soluble solids content showed same trend in the soil water potential, but titratable acidity, anthocyanins and total polyphenols were not significantly different. Therefore, the optimal soil water potential for the development and a maximum production of HB were a range of -4~-8 kPa, and the recommended ideal irrigation trigger point was within -15 kPa.

• Journal of Aquaculture
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• v.18 no.3
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• pp.147-153
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• 2005

The objective of this study is to elucidate the growth pattern of dark-banded rockfish, Sebastes inermis Cuvier, produced by aquaculture in Korea. Larvae from 250 maternal full-sibs were reared until 1,350 days after parturition. During the rearing period, growth equations on days after parturition (X) to the total length (TL) and body weight (BW) were estimated as TL=0.0217X $(r^2=0.8867)$ and $BW=0.0001X^2+0.0713X\;(r^2=0.9858)$, respectively. The relationship between BW and TL was $BW=0.0072TL^{3.4373}\;(r^2=0.9945)$. An increases in the eye diameter (ED) of dark-banded rockfish larvae on days after parturition (X) could be expressed as $ED=-2E-5X^2+0.0326X\;(r^2=0.9886)$. Relative growth equations on TL to head length (HL), snout length (SL), ED and postorbital head length (PHL) were calculated as $HL=0.2652TL\;(r^2=0.9758),\;SL=0.0613TL\;(r^2=0.9602),\;ED=0.0752TL\;(r^2=0.9715)$ and $PHL=0.2652TL\;(r^2=0.9501)$, respectively. Since there were few reports on the long-term growth experiment of this species due to difficulties in rearing techniques, results of this study would give a useful information to the biology and commercial culture techniques of dark-banded rockfish.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.63-64
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• 1996

The nature of distant faint blue field galaxies remains a mystery, despite the fact that much attention has been devoted to this subject in the last decade. Galaxy counts, particularly those in the optical and near ultraviolet bandpasses, have been demonstrated to be well in excess of those expected in the 'no-evolution' scenario. This has usually been taken to imply that galaxies were brighter in the past, presumably due to a higher rate of star formation. More recently, redshift surveys of galaxies as faint as B$\~$24 have shown that the mean redshift of faint blue galaxies is lower than that predicted by standard evolutionary models (de-signed to fit the galaxy counts). The galaxy number count data and redshift data suggest that evolutionary effects are most prominent at the faint end of the galaxy luminosity function. While these data constrain the form of evolution of the overall luminosity function, they do not constrain evolution in individual galaxies. We are carrying out a series of observations as part of a long-term program aimed at a better understanding of the nature and amount of luminosity evolution in individual galaxies. Our study uses the luminosity-linewidth relation (Tully-Fisher relation) for disk galaxies as a tool to study luminosity evolution. Several studies of a related nature are being carried out by other groups. A specific experiment to test a 'no-evolution' hypothesis is presented here. We have used the AUTOFIB multifibre spectro-graph on the 4-metre Anglo-Australian Telescope (AAT) and the Rutgers Fabry-Perot imager on the Cerro Tolalo lnteramerican Observatory (CTIO) 4-metre tele-scope to measure the internal kinematics of a representative sample of faint blue field galaxies in the red-shift range z = 0.15-0.4. The emission line profiles of [OII] and [OIII] in a typical sample galaxy are significantly broader than the instrumental resolution (100-120 km $s^{-l}$), and it is possible to make a reliable de-termination of the linewidth. Detailed and realistic simulations based on the properties of nearby, low-luminosity spirals are used to convert the measured linewidth into an estimate of the characteristic rotation speed, making statistical corrections for the effects of inclination, non-uniform distribution of ionized gas, rotation curve shape, finite fibre aperture, etc.. The (corrected) mean characteristic rotation speed for our distant galaxy sample is compared to the mean rotation speed of local galaxies of comparable blue luminosity and colour. The typical galaxy in our distant sample has a B-band luminosity of about 0.25 L$\ast$ and a colour that corresponds to the Sb-Sd/Im range of Hub-ble types. Details of the AUTOFIB fibre spectroscopic study are described by Rix et al. (1996). Follow-up deep near infrared imaging with the 10-metre Keck tele-scope+ NIRC combination and high angular resolution imaging with the Hubble Space Telescope's WFPC2 are being used to determine the structural and orientation parameters of galaxies on an individual basis. This information is being combined with the spatially resolved CTIO Fabry-Perot data to study the internal kinematics of distant galaxies (Ing et al. 1996). The two main questions addressed by these (preliminary studies) are: 1. Do galaxies of a given luminosity and colour have the same characteristic rotation speed in the distant and local Universe? The distant galaxies in our AUTOFIB sample have a mean characteristic rotation speed of $\~$70 km $s^{-l}$ after correction for measurement bias (Fig. 1); this is inconsistent with the characteristic rotation speed of local galaxies of comparable photometric proper-ties (105 km $s^{-l}$) at the > $99\%$ significance level (Fig. 2). A straightforward explanation for this discrepancy is that faint blue galaxies were about 1-1.5 mag brighter (in the B band) at z $\~$ 0.25 than their present-day counterparts. 2. What is the nature of the internal kinematics of faint field galaxies? The linewidths of these faint galaxies appear to be dominated by the global disk rotation. The larger galaxies in our sample are about 2"-.5" in diameter so one can get direct insight into the nature of their internal velocity field from the $\~$ I" seeing CTIO Fabry-Perot data. A montage of Fabry-Perot data is shown in Fig. 3. The linewidths are too large (by. $5\sigma$) to be caused by turbulence in giant HII regions.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.361-371
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• 2005

The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.484-492
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• 2012

The present study aimed to investigate the effect of static magnetic field (SMF) on the growth and physiological characteristics of common indoor plant species. Five foliage plant species, Spathiphyllum spp., Ardisia pusilla DC., Syngonium podophyllum, Peperomia pereskiifolia, and Pilea cadierei were potted into plastic pot equipped with round type anisotropic sintered NdFeB permanent magnet inside the pot. The surface magnetic flux density of each magnet was 3,500 G. After 6 months of growth period, the biomass accumulations of Spathiphyllum, A. pusilla, and P. cadierei under SMF were statistically higher than those of controls. Tissue water content also increased under the influence of SMF in most species. The photosynthetic rate of Spathiphyllum under SMF significantly increased but other species showed no significant difference compared with control. Although there was no significant increase in the photosynthetic rates of A. pusilla, and P. cadierei, they showed remarkable increase in total fresh weight under SMF. This suggests that the demand of assimilates for normal metabolism could be decreased under magnetic influence and thereby biomass accumulation could be more favored. But this is not always true for all plant species because P. pereskiifolia in this experiment, showed no changes in both photosynthetic rate and biomass accumulation. Leaf nitrogen and chlorophyll contents were enhanced significantly in most plant species under influence of SMF. Chlorophyll a/b ratio also increased by SMF. Although there might be a limitation depending on plant species, these results suggest that long-term exposure to SMF might allow plant to have an enhanced acclimation capacity against environmental fluctuations and optimal application of SMF could increase the practical use of indoor plants such as an attempt to improve indoor air quality.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.376-383
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• 2003

To utilize composts more efficiently, combining composts with fertilizer to meet crop requirements is an appealing alternative. A pot experiment was conducted to study the effect of application rate of composted pig manure blended with fertilizer on the availability and loss of fertilizer-N. Chinese cabbage (Brassica campestris L. cv. Samjin) plants were cultivated for 30 and 60 days. 15N-Labeled urea ($5.24\;^{15}N\;atom\;%$) was added to soil at $450mg\;N\;kg^{-1}$, and unlabeled compost ($0.37\;^{15}N\;atom\;%$) was added at 0, 200, 400, and $600mg\;N\;kg^{-1}$. The amount of plant-N derived from urea was not affected by compost application at rate of $200mg\;N\;kg^{-1}$. However, compost application at 400 and $600mg\;N\;kg^{-1}$ significantly (P<0.05) increased plant assimilation of N from urea irrespective of sampling time, probably because of physicochemical changes in the soil properties allowing urea-N to be assimilated more efficiently. The amount of immobilized urea-N increased with increasing rate of compost application at both growth periods, as the results of increased microbial activities using organic C in the compost. Total recovery of urea-N (as percentage of added N) by Chinese cabbage and soil also increased with increasing rate of compost from 71.5 to 95.6% and from 67.0 to 88.2% at the 30- and 60-days of growth, respectively. These results suggest that increasing rate of compost blending increases plant uptake of fertilizer-N and enhances immobilization of fertilizer-N, which leads to decrease in loss of fertilizer-N. However, information about the fate of immobilized N during future crop cultivation is necessary to verify long-term effect of compost blending.