• Mycobiology
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• v.33 no.4
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• pp.188-193
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• 2005

Twenty nine samples of pigeon droppings (n = 12) and soil contaminated with avian excreta (n = 19), collected from different sites in Busan, were examined for isolation and characterization of Cryptococcus neoformans. Of these samples, 5 strains of C. neoformans were recovered from pigeon droppings (5/12 : 41.7%). All isolates were belonged to C. neoformans var. grubii (serotype A). The extracellular enzyme activities of the strains by using the API-ZYM system showed two different enzymatic patterns. The genetic variability among C. neoformans isolates was analyzed by random amplified polymorphic DNA (RAPD) using three 10-mer primers. Two different RAPD patterns, which clearly distinguished the isolates, were identified. Analysis of RAPD patterns provided a good characterization of environmental strains of C. neoformans serotype A as a heterogeneous group and were in good agreement with enzymatic profiles.

• Journal of Species Research
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• v.9 no.4
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• pp.462-466
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• 2020

Testate amoebae are easily recognized as their characteristic shells from other protistan groups. They in which more than 1,900 species have been recorded are mixture of heterogeneous groups mainly composed of Amoebozoa and Cercozoa. In Korea, 74 species of testate amoebae have been recorded since late 1980s. Here I report a list of 12 unrecorded species of testate amoebae from Korea which were discovered during 2016-2018: Arcella crenulata Deflandre, 1928; Centropyxis cassis(Wallich, 1864); C. delicatula Penard, 1902; C. hirsuta Deflander, 1929; C. orbicularis Deflandre, 1929; C. sylvatica (Deflandre, 1929); Cyclopyxis eurystoma Deflandre, 1929; C. intermedia Kufferath, 1932; C. kahli(Deflandre, 1929); Difflugia diafana Vucetich, 1987; D. manicata Penard, 1902; Awerintzewia cyclostoma Schoutenden, 1906. As a result the fauna of testate amoebae in Korea is composed of 86 species. There are still much more species remained to be discovered in Korea. The faunal studies on testate amoebae will provide us valuable information about freshwater and soil environments.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1512-1517
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• 2008

Laboratory column tests were conducted in this study using $Cl^-$ tracers on Jumunjin sand to analyze contaminant transport in mixed contaminated soils. Results obtained from clean soils and soils containing residual diesel verified heterogeneous distribution of residual diesel, and clear acceleration of solute movement. In addition, asymmetric breakthrough curves indicated development of immobile region where solute movement becomes stagnant and creates tailing phenomenon.

• Korean Journal of Microbiology
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• v.21 no.4
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• pp.238-244
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• 1983

In order to obtain Ti plasmid which may be used in genetic engineering of higher plants, virulent Agrobacterium tumefaciens were isolated from soil with selective medium. For their identification, morphological and cultural characteristics were investigated in parallel with physiological and turnorigenesis test. 14 strains were isolated from various regions in Korea. 3 of them were identified as biotype 1 and the others were so heterogeneous that they are not yet conformed to any biotypes. However, Ti plasmid was isolated from A. tumefaciens KU 14 strain, one of the above mentioned 14 strains.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.759-768
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• 2015

The ground motions of large dimensional structures such as long span bridges at different stations during an earthquake, are inevitably different, which is known as the ground motion spatial variation effect. There are many causes that may result in the spatial variability in seismic ground motion, e.g., the wave passage effect due to the different arrival times of waves at different locations; the loss of coherency due to seismic waves scattering in the heterogeneous medium of the ground; the site amplification effect owing to different local soil properties. In previous researches, the site amplification effects have not been considered or considered by a single-layered soil model only. In this study, however, the ground motion amplification and filtering effects are evaluated by multi-layered soil model. Spatially varying ground motion at the sites with different number of layers, depths, and soil characteristics are generated and the variation characteristics of ground motion time histories according to the correlation of coherency loss function and soil conditions are evaluated. For the bridge system composed of two unit bridges, seismic behavior characteristics are analyzed using the generated seismic waves as input ground motion. Especially, relative displacement due to coherency loss and site effect which can cause the unseating and pounding between girders are evaluated. As a result, considering the soil conditions of each site are always important and should not be neglected for an accurate structural response analysis.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.107-116
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• 2020

In this data paper, we share the dataset obtained during 2019 from the test-bed to develop soil moisture estimation technology for upland fields, which was built in Seosan and Taean, South Korea on May 3. T his dataset includes various eco-hydro-meteorological variables such as soil moisture, evapotranspiration, precipitation, radiation, temperature, humidity, and vegetation indices from the test-bed nearby the Automated Agricultural Observing System (AAOS) in Seosan operated by the Korea Meteorological Administration. T here are three remarkable points of the dataset: (1) It can be utilized to develop and evaluate spatial scaling technology of soil moisture because the areal measurement with wide spatial representativeness using a COSMIC-ray neutron sensor as well as the point measurement using frequency/time domain reflectometry (FDR/TDR) sensors were conducted simultaneously, (2) it can be used to enhance understanding of how soil moisture and crop growth interact with each other because crop growth was also monitored using the Smart Surface Sensing System (4S), and (3) it is possible to evaluate the surface water balance by measuring evapotranspiration using an eddy covariance system.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.2
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• pp.90-99
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• 1994

Heterogeneous hydraulic conductivity in a flow domain is generated under the assumption that it is a random variable with a lognormal, spatially-correlated distribution. The hydraulic head and the conductivity in a groundwater flow system are represented as a stochastic process. The method of Monte Carlo Simulation (MCS) and the finite element method (FEM) are used to determine the statistics of the head and the logconductivity. The second moments of the head and the logconductivity indicate that the cross-covariance of the logconductivity with the head has characteristic distribution patterns depending on the properties of sources, boundary conditions, head gradients, and correlation scales. The negative cross-correlation outlines a weak-response zone where the flow system is weakly responding to a stress change in the flow domain. The stochastic approach has a potential to quantitatively delineate the zone of influence through computations of the cross-covariance distribution.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.4
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• pp.180-187
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• 1999

Transmissivity is often estimated from specific capacity data because of the expense of conducting standard aquifer test to obtain transmissivity and the relative availability of specific capacity data. Most often, analytic expression relating specific capacity to transmissivity derived by Theis (1963). Brown (1963). and Logan (1964) are used in this analysis. The analytic solution typically used to predict transmissivity from specific capacity in alluvial aquifers assuming influence radius and/or storage coefficient of the aquifers. But those do not agree well with the measured transmissivity in fractured rock aquifers and in heterogeneous aquifers. Razack-Huntely (199l). Huntely-Steffey (1992). and Mace (1997) proposed emphirical rotations between specific capacity and transmissivity in heterogeneous alluvial aquifers. fractured rock aquifers, and karst aquifers. This study focuses on comparison between transmissivity and specific capacity data in volcanic rock aquifers of Jeju Island. Emphirical relation between the log of transmissivity and the log of specific capacity suggests they no linearly related (correlation coefficient 0.951) and the width of $\pm$0.25 log cycles in transmissivity includes 96.6% of data.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.1-8
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• 2006

The objective of this study is to assess impacts of sorption heterogeneity on the transport of leachate leaked from unlined landfill sites and is accomplished by examining the results from a series of Monte-Carlo simulations. For random distribution coefficient ($K_{d}$) fields with four different levels of heterogeneity ranging from homogeneous to highly heterogeneous, the transport of leachate was investigated by linking a saturated flow model with a contaminant transport model. Impacts of a chemical heterogeneity were evaluated using point statistics values such as mean, standard deviation, and coefficient of variation of the concentration obtained at monitoring wells from 100 Monte-Carlo trials. Inspection of point statistics shows that the distribution of distribution coefficient in the landfill site proves to be an important parameter in controlling leachate concentrations. In comparison to homogeneous sorption, heterogeneous $K_{d^-}$ fields produce the variability in the leachate concentration for different realizations. The variability increases significantly as the variance in the $K_{d^-}$ field and the travel time between source and monitoring well increase. These outcomes indicate that use of a constant homogeneous $K_{d}$ value for predicting the transport of leachate can result in significant error, especially when variability in $K_{d}$ is high.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.91-95
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• 2004

For the detection of the oil-degrading bacterium, Nocardia sp. Hl7-1, inoculated during the bioremediation of oil-contaminated soil, a species-specific primer was constructed based on the 16S rDNA sequence of this strain. Two forward primers and two reverse primers were designed and tested against both closely and distantly related bacterial strains. All the primers designed were specific to the Nocardia sp. H17-1. Particularly, primer sets NH169F-NH972R and NH575F-NH972R could be used to detect 50 fg of template DNA and TEX>$1.2${\times}$10^4$ CFU/g of sandy soil. These two PCR primer sets successfully detected the H 17-1 strain in the oil-con-laminated soil samples containing heterogeneous DNA. We also conformed the primer specificity by restriction-enzyme cleavage of the PCR products and denaturing gradient gel electrophoresis.